Citations 

Citation for entire document:
 

Whitall, D., L.J. Bauer, C. Sherman, K. Edwards, A. Mason, T. Pait, and C. Caldow. 2013. Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration. NOAA Technical Memorandum
 

NOS NCCOS 176. Prepared by the NCCOS Center for Coastal Monitoring and Assessment Biogeography 

Branch. Silver Spring, MD. 169 pp.
 

Example citation for an individual chapter:
 

Bauer, L.J., K. Edwards and C. Caldow. 2013. Baseline Characterization of Fish Communities and Associated Benthic Habitats in the Guánica Bay Region of Southwest Puerto Rico. pp. 5-62. In Whitall,D., L.J. Bauer, 

C. Sherman, K. Edwards, A. Mason, T. Pait, and C. Caldow. 2013. Baseline Assessment of Guánica Bay, 

Puerto Rico in Support of Watershed Restoration. NOAA Technical Memorandum NOS NCCOS 176. Prepared by the NCCOS Center for Coastal Monitoring and Assessment Biogeography Branch. Silver Spring, 

MD. 169 pp. 

Acknowledgements 

The authors would like to thank the many contributors to this report. Their efforts to review, edit, design and 

format the document are greatly appreciated. Many thanks to: Captain Angel Nazario of the vessel Aquanauta and his assistant Joel (Joito) Rivera for getting us safely to and from our sites. Kimberly Roberson, Simon 

Pittman, and Randy Clark assisted in the collection of field data. Thanks to Chris Jeffrey, Simon Pittman, 

Sean Griffin, Christine Addison Buckel, Reni Garcia-Sais, Suzanne Bricker, Greg Piniak, David Sotomayor, 

Luis Perez, Paul Sturm, Alicia Clarke, JamisonHiggins, Kevin McMahon and Tracy Gill for providing useful 

comments and editorial assistance. 

The covers for this document were designed and created by Gini Kennedy. Cover photos were provided 

by the National Centers for Coastal Ocean Science (NCCOS). This work was funded NOAA’s Coral Reef 

Conservation Program, with personnel support from NOAA’s NCCOS and NOAA’s Restoration Center. 

Government contract labor was provided by CSS-Dynamac, Fairfax, VA under NOAA contract number 

#DG133C11CO0019. 

Mention of trade names or commercial products does not constitute endorsement or recommendation for 

their use by the United States government. 
Baseline Assessment of Guánica Bay, Puerto Rico in 

Support of Watershed Restoration
 

Prepared by:
 

Center for Coastal Monitoring and Assessment (CCMA)
 

NOAA National Centers for Coastal Ocean Science (NCCOS)
 

Silver Spring, MD
 

USA
 

December 2013
 

Authors
 

David Whitall
 

Laurie J. Bauer 

Clark Sherman

 Kimberly Edwards

 Andrew Mason

 Tony Pait
 

Chris Caldow
 

NOAA Technical Memorandum NOS NCCOS 176 

United States Department National Oceanic and National 

of Commerce Atmospheric Administration Ocean Service 

Penny Pritzker 

Secretary 

Kathryn Sullivan 

Acting Administrator 

Holly Bamford 

Assistant Administrator 

About this doCument 

This document presents a comprehensive overview of results from a recent baseline assessment of Guánica 

Bay, Puerto Rico and its surrounding coral reef ecosystem. The report details: (1) a biogeographic assessment of the coral reef ecosystem outside the bay; (2) contaminant (e.g., PAHs, PCBs, pesticides, heavy metals) magnitudes and distributions in surface sediments (inside the bay, outside the bay and in the watershed 

streams) and in coral tissues (mustard hill coral, Porites astreoides); and (3) spatial and temporal patterns 

in sedimentation rates and surface water nutrient concentrations. 

The efforts discussed here were led by the National Centers for Coastal Ocean Science (NCCOS), with 

significant participation from partners, both internal to NOAA (e.g., Coral Reef Conservation Program) and 

external to NOAA (e.g., University of Puerto Rico). NCCOS has been proactive in collaborating with other 

NOAA line offices as well as federal, state and nongovernmental organization partners to maximize costsharing efforts and reach its goals. Their efforts and extramural funding has made it possible to complete 

areas that would have otherwise been unobtainable through federal funding alone. 

Live hyperlinks to related products (indicated by blue, underlined text) are embedded throughout this report 

and are accessible when viewing this document as a PDF. For more information about this report and others 

like it, please visit the NCCOS web site, http://coastalscience.noaa.gov/, or direct comments to: 

mark monaco, Phd, director 

Center for Coastal Monitoring and Assessment 

NOAA National Centers for Coastal Ocean Science 

Telephone: 301.713.3020 x160 

E-mail: Mark.Monaco@noaa.gov 

david Whitall, Phd 

National Centers for Coastal Ocean Science 

Center for Coastal Monitoring and Assessment 

(301) 713-3028 x138 

Dave.Whitall@noaa.gov 
 

 

 

 

 

tAble of Contents 

executive summary i
 David Whitall 

Chapter 1: Introduction and Background 1
 David Whitall, Laurie Bauer and Lia Brune 

Background 1
 

Study Area 1
 

Previous Studies 3
 

Management Actions 3
 

Study Objectives 3
 

References 4
 

Chapter 2: Fish Communities and Associated Benthic Habitats in the Guánica Bay Region of 

Southwest Puerto Rico 5
 Laurie Bauer, Kimberly Edwards and Chris Caldow 

Background 5
 

Methods 6
 

Data Analysis 9
 

Results and Discussion 10
 

Conclusions 57
 

References 60
 

Chapter 3: Contaminants in Surficial Sediments and Coral Tissues of Guánica Bay 63
 David Whitall, Andrew Mason, Lia Brune, Anthony Pait, Michael Fulton, Ed Wirth, Lisa Vandiver and Matthew Poti 

Contaminant Background 63
 

Major and Trace Elements 65
 

Methods 66
 

Statistical Analysis 68
 

Contaminant Results and Discussion 69
 

Conclusions 98
 

References 99
 

Chapter 4: Terrigenous Sedimentation Patterns at Reefs Adjacent to the 

Guánica Bay Watershed 103
 Clark Sherman, Raquel Hernandez, Yahaira Hutchinson and David Whitall 

Background 103
 

Methodology 103
 

Results 104
 

Discussion 108
 

Conclusions 110
 

References 112
 
 

tAble of Contents 

Chapter 5: Spatial and Temporal Variability in Surface Water Nutrients in and around 

Guánica Bay, Puerto Rico 113
 David Whitall and Clark Sherman 

Background 113
 

Methods 113
 

Results and Discussion 115
 

Conclusions 130
 

References 131
 

Chapter 6: Conclusions 133
 David Whitall and Laurie Bauer 

Appendix A 135
 

Appendix b 145
 

Appendix C 163
 

Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

i Executive Summary

eXeCutiVe summARY 

David Whitall1 

Guánica Bay is a major estuary on the 

southwest coast of Puerto Rico. Significant 

coral reef ecosystems are present outside 

the bay. These valuable habitats may be 

impacted by transport of sediments, nutrients and contaminants from the watershed, 

through the bay and into the offshore waters. The National Oceanic and Atmospheric 

Administration’s (NOAA) National Centers 

for Coastal Ocean Science (NCCOS), in 

consultation with local and regional experts, 

conducted an interdisciplinary assessment 

of coral reef ecosystems, contaminants, 

sedimentation rates and nutrient distribution patterns in and around Guánica Bay. 

This work was conducted using many of the 

same protocols as ongoing monitoring work 

underway elsewhere in the U.S. Caribbean 

and has enabled comparisons among coral 

reef ecosystems between this study and 

other locations in the region. 

This characterization of Guánica marine 

ecosystems establishes benchmark conditions that can be used for comparative documentation of future change, including possible negative outcomes due to 

future land use change, or improvement in environmental conditions arising from management actions. 

This report is organized into six chapters that represent a suite of interrelated studies. Chapter 1 provides a short introduction to the study area. Chapter 2 is focused on biogeographic assessments and benthic mapping of the study area, 

including new surveys of fish, marine debris and reef communities on hardbottom habitats in the study area. Chapter 3 

quantifies the distribution and magnitude of a suite of contaminants (e.g., heavy metals, PAHs, PCBs, pesticides) in both 

surface sediments and coral tissues. Chapter 4 presents results of sedimentation measurements in and outside of the 

bay. Chapter 5 examines the distribution of nutrients in in the bay, offshore from the bay and in the watershed. Chapter 6 

is a brief summary discussion that highlights key findings of the entire suite of studies. 

The main findings of each chapter are as follows: 

Chapter 1: Introduction 

•	 Historical agricultural land use (sugar cane farming) has given way to a mosaic of land use types. Current 

land use consists of agriculture, including coffee farming in the mountains, small urban areas and forest. 

•	 Human alteration of the hydrology of the watershed via irrigation and drainage projects has resulted in a 

complex water cycle within the watershed. 

•	 Offshore marine ecosystem features include both emergent and submergent reefs, seagrass beds, mangrove islands and fringing mangroves. 

•	 The general long shore current direction is east to west. 

Chapter 2: Fish Communities and Associated Benthic Habitats in the Guánica Bay Region of Southwest Puerto Rico 

•	 Coral cover was generally low across the study region. 

•	 Gorgonian, sea grass and coral cover were higher in the La Parguera region, to the west of the study area. 

•	 The study region in Guánica Bay had lower coral cover than other studies in the region. 

Guánica Bay, a major estuary in southwest Puerto Rico, is home to many species 

of coral, fish, seagrass and invertebrates. Photo: NCCOS. 

1. NOAA/NOS/NCCOS 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

ii Executive Summary

Chapter 3: Contaminants in Surficial Sediments and Coral Tissues of Guánica Bay
	

•	 Surface sediment samples demonstrated unusually high concentrations of total chlordane, total PCBs, nickel 

and chromium. 

•	 A variety of other contaminants (total DDT, total PAHs, arsenic, copper, mercury and zinc) were also at levels 

which may indicate sediment toxicity. 

•	 Elevated concentrations of pollutants were generally limited to inside the bay, although several contaminants 

(chlordane, PCBs, chromium) were elevated outside the bay as well. 

•	 With the exception of chromium, all of these contaminants were detected in coral tissues mustard hill coral, 

(Porites asteroides), although it is unclear at what level these contaminants affect coral health. 

Chapter 4: Terrigenous Sedimentation Patterns at Reefs Adjacent to the Guánica Bay Watershed 

•	 Sediment trap accumulation rates vary both spatially and temporally. 

•	 The composition of the deposited material remains fairly constant, independent of sedimentation rate. This 

indicates that re-suspension of sediments is likely very important in this system. 

•	 No east-west pattern in sedimentation rates was observed. 

Chapter 5: Spatial and Temporal Variability in Surface Water Nutrients in and around Guánica Bay, Puerto Rico 

•	 Observed nutrient concentrations suggest a strong watershed source of nutrients with dilution as nutrients 

move into the bay and offshore. 

•	 Phosphorus rarely exceeded previously published threshold values for coral impact; however, approximately 

10% of the observations had DIN values which exceeded this proposed threshold. 

•	 In general, there was no obvious nutrient spike related to the wastewater treatment plant (WWTP) in the 

bay. On one occasion the site closest to the WWTP had an anomalously high nitrogen value, suggesting that 

something unusual may have occurred around that time, but that was an isolated incident. 

Chapter 6: Conclusions 

•	 This suite of environmental data (biological and stressors) represents an important baseline against which 

future change can be measured. Change might occur due to human induced degradation (e.g., due to 

coastal development) or due to improvements associated with management actions. 

•	 Further monitoring and assessments are needed to detect changes in the ecosystem over a variety of time 

scales ranging from relatively short-term responses in sediment loading, to potentially decadal-long recovery 

processes for reef systems. 
Baseline Assessment of Guanica Bay, Puerto Rico in Support of Watershed Restoration

1 Introduction

Chapter 1: introduction and background 

David Whitall1, Laurie Bauer1,2 and Lia Brune1 

bACkgRound 

Coral reefs are among the largest and most biologically diverse ecosystems on the planet. Reefs provide a variety of 

goods and services to people, such as seafood, shoreline protection, recreation and tourism, new medicines, and aesthetics (Burke and Maidens, 2004; Dixon, 1998; Moberg and Folke, 1999). Costanza et al. (1997) found that globally 

these ecosystem services are valued at $US 375 billion per year. 

Yet, over half of the world’s coral reefs are threatened by human activity (Bryant et al., 1998). Increased runoff of sediment, nutrients and pollutants has been correlated to the degradation of coral reefs (Fabricius, 2005). In the Caribbean, it 

is estimated that one third of coral reefs are threatened by land-based sources of pollution, much of which is exacerbated 

by coastal development (Burke and Maidens, 2004; Moberg and Folke, 1999). Although pollution is a known cause of 

the decline of coral reefs, details of the relationship between contaminants and corals are not well understood. There are 

currently no established thresholds for individual pollution stressors indicating concentration limits above which adverse 

biological effects or the potential for effects occur in coral tissues. 

This study presents a baseline assessment of the biological resources of coral reefs off the coast of Guánica Bay, Puerto 

Rico, as well as the magnitude and spatial distribution of pollutant stressors (sediments, nutrients, contaminants) to this 

system. This information will provide ecosystem managers a reference point against which to evaluate the success of upland watershed restoration efforts and best management practices (e.g., those planned by the NOAA Restoration Center, 

USDA Natural Resource Conservation Service and non-governmental organizations.) This baseline assessment supports 

the Guánica Bay Watershed Management Plan which was created in response to the U.S. Coral Reef Task Force Local 

Action Strategy for Puerto Rico. The plan addresses land-based sources of pollution and proposes methods to reduce the 

loss of coral reefs through implementing effective watershed management planning (CWP, 2008). 

studY AReA 

Marine Ecosystem

The study area encompasses Guanica Bay itself and the coral reef ecosystems located offshore. The bay is approximately 3 km long and 2.5 km wide, at its widest point. The mouth of the bay is relatively narrow (less than 1 km), which 

influences the exchange with the open ocean. There are no living reefs within the bay. The coral reef ecosystem of this 

region is a complex spatial mosaic of habitat types including extensive coral reefs, submerged aquatic vegetation and 

mangroves, which in turn support diverse fish communities (Pittman et al., 2010). The shelf within the marine study area 

is three to four kilometers wide and average water depth is 12 meters. Both emergent and submergent reefs separate 

the inner shelf from the outer shelf. Sea grass beds and both fringing mangroves and mangrove islands are scattered 

throughout the study area (Bauer et al., 2012; Kendall et al., 2001). The predominant long shore flow of the area is east 

to west (CFMC, 1998). A sediment plume originating from Guánica Bay and flowing to the west is commonly observed on 

satellite imagery. 

Watershed Hydrology

Guánica Bay is located on the coast of southwestern Puerto Rico in the Guánica municipality (Figure 1.1). The bay is fed 

directly by one river, the Rio Loco, which runs year round, but exhibits high flows during the rainy season. In the 1950s, 

the Southwest Water Project increased the drainage area of the watershed through a series of reservoirs, canals and 

hydroelectric plants. Consequently, the Guánica watershed actually encompasses five basins and associated reservoirs: 

Lago Yahuecas, Lago Guayo, Lago Prieto, Lago Luccheti and Lago Loco, as well as the Lajas Irrigation Canal within the 

Lajas Valley Agricultural Reserve (CWP, 2008). This water diversion system persists today, moving water from the upper watershed to the Lajas Valley to the west. This system not only provides agricultural irrigation water, it also provides 

drinking water to the municipalities of Sabana Grande, Cabo Rojo, San Germán and Lajas. Drainage canals also move 

water, primarily originating from overland runoff, to the east where the drainage canal re-joins the Rio Loco just upstream 

of its entry point into the bay. The Guánica Lagoon, previously situated to the north of the bay, was historically the largest freshwater lagoon in Puerto Rico and may have served as a natural filter and sediment sink prior to the discharge of 

the Rio Loco into the bay. Following alterations by the Southwest Water Project, a large portion of the Lajas Valley (over 

20,000 hectares; Sotomayor and Pérez, 2011) including the lagoon and its surrounding wetlands system, was drained for 

agricultural use. 

1. NOAA/NOS/NCCOS

2. CSS-Dynamac, Fairfax, VA 
Baseline Assessment of Guanica Bay, Puerto Rico in Support of Watershed Restoration

2 Introduction

Figure 1.1. Location of Guanica Bay, Puerto Rico. 

Watershed Land Use 

Land use in the Guánica Bay/Rio Loco watershed has changed over time (CWP, 2008). Historically, sugar cane, coffee, 

tobacco and sustenance crops were grown in Lajas Valley. Agricultural production has declined since the 1950s due to a 

shift in government policy and a move towards small industry. This led to the abandonment of farmlands, most of which 

became pastureland or urban areas (Cramer and Hobbs, 2007). This conversion of land use from forested to agricultural, 

and then to urban development has contributed significantly to the increased nutrient and sediment loads, the latter of 

which can lead to decreases in water clarity, along the shelf of southwest Puerto Rico (Larsen and Webb, 2009). A movement from shade-grown to sun-grown coffee cultivation in Puerto Rico began around the same time period in efforts to 

increase yields. The sun-grown cultivation method requires more chemical inputs than shade-grown coffee and causes 

higher runoff due to the lack of canopy cover (Perfecto et al.,1996). Returning to shade-grown coffee cultivation is one 

of many watershed management practices proposed as part of the Guánica Bay Watershed Management Plan. Other 

methods for reducing sediment load (e.g., hydroseeding, stream bank stabilization) are also being considered. Increasing 

urban and industrial developments around Guánica Bay, as well as further upland, have led to increased pollutant and 

nutrient loadings entering the bay via storm water runoff and wastewater effluent (Warne et al., 2005). 

Current land use in the watershed includes 48% forested, 43% agriculture and 9% urban (CWP, 2008). The Guánica State 

Forest (Bosque Estatal de Guánica) and UNESCO Biosphere Reserve extends to the west and east of Guánica Bay. The 

northern area of the watershed is generally mountainous and is characterized by a mix of forested and agricultural lands, 

including coffee plantations, which may be especially important in terms of sediment loss. Closer to the coast, the Lajas 

Valley Agricultural Reserve extends north of Guánica Bay to the southwest corner of the island. There are two sewagetreatment plants in the tidal areas of the Guánica watershed (CWP, 2008). The largest of these is located on the eastern 

shore of the bay and discharges its treated effluent into the bay. This facility has tertiary treatment capabilities. Guánica 

Bay is bordered by the municipality of Guánica, which encompasses the coastal towns of Guánica and Ensenada. The 

municipality has a population of approximately 22,000 and the regions surrounding Guánica Bay have historically been 

home to various industries including sugar processing, textiles and fertilizer mixing (U.S. Census Bureau, 2003). 

Increased sediment and nutrient discharge into the Rio Loco and ultimately to Guánica Bay’s near shore reefs is attributed to land use changes (Warne et al., 2005). The conversion of upland forested lands to agriculture and man-made 

canals has altered the natural hydrology of the watershed causing upland soil erosion, in-stream channel erosion, loss of 

lagoons and the downstream transport of sediment (CWP, 2008). A study by Larsen and Santiago-Roman (2001) showed 

that large quantities of sediment from upland hill-slopes were deposited in lower hill-slopes and stream valleys all across 

Puerto Rico during the agriculture peak of the mid twentieth century. Larsen and Santiago-Roman (2001) estimated that 

this stored sediment would be available for dispersal for a century or more, and has the potential to reach the offshore 

coral reef systems via riverine transport and export from the bay. 
Baseline Assessment of Guanica Bay, Puerto Rico in Support of Watershed Restoration

3 Introduction

PReVious studies 

The land use practices and watershed changes outlined above have resulted in large amounts of sediment being distributed in the Rio Loco river valley (CWP, 2008). Storm events and seasonal flooding also transport large amounts of sediment to the coastal waters. Previous work has indicated that contaminant levels are higher in Guánica Bay compared to 

the surrounding area (Pait et al., 2008; Pait et al., 2009). In particular, concentrations of PCBs (polychlorinated biphenyls) 

and DDT (dichlorodiphenyltrichloroethane) in sediment samples from within the bay were above established guideline 

levels that are frequently associated with toxic effects to the biota (Pait, 2008). In addition, among coral tissue mustard 

hill coral, (Porites astreoides) samples collected from southwest Puerto Rico, levels of these same contaminant classes 

were highest in samples taken closest to Guánica Bay, and there was evidence of a downstream gradient moving away 

from the bay (Pait et al. et al., 2009). 

mAnAgement ACtions 

The threats of upstream watershed practices to coral reefs and the nearshore marine environment have been gaining 

recognition. Guánica Bay and the adjacent marine waters have been identified as a “management priority area” by the 

Commonwealth of Puerto Rico and NOAA’s Coral Reef Conservation Program (Commonwealth of Puerto Rico and NOAA 

CRCP, 2010) and as a U.S. Coral Reef Task Force Priority Watershed (USCRTF, 2011). In a recent Guánica Bay watershed management plan, several critical issues were outlined in regards to land-based sources of pollution (CWP, 2008). 

These include: upland erosion from coffee agriculture, filling of reservoirs with sediment, in-stream channel erosion, loss 

of historical Guánica lagoon, legacy contaminants and sewage treatment (CWP, 2008). The plan recommended several 

management actions that could be taken to reduce impacts of land-based sources of pollution, which form the basis of 

Guánica watershed restoration efforts. The Guánica watershed restoration project is a multi-disciplinary, multi-faceted 

effort with numerous federal and territorial partners, including the NOAA National Centers for Coastal Ocean Science 

(NCCOS) COAST and Biogeography Branches, Coral Reef Conservation Program, Restoration Center, USDA’s Natural 

Resources Conservation Service and multiple non-governmental organizations. Current and proposed restoration projects in the watershed include the restoration of the historic Guánica Lagoon and adjacent coastal wetlands, conversion of 

sun-grown to shade-grown coffee, sewage treatment upgrades and stabilization of the Rio Loco river channel. A primary 

objective of these restoration activities is to reduce nutrient and sediment loading into the marine environment, with the 

ultimate goal of improving coral reef health. 

studY objeCtiVes 

In order to measure the effectiveness of restoration efforts, it is critical that baseline data be collected with which potential 

future changes can be quantified. The objective of the ecological characterization of the Guánica Bay region is to conduct 

a baseline assessment with which the success of these efforts can be evaluated. 

The objectives of this assessment are to: 

1.	 Characterize fish and benthic communities of the Guánica Bay region, and compare these metrics with 

the neighboring La Parguera study area, which has been monitored by NOAA since 2001 (Pittman et al., 

2010). 

2.	 Measure the spatial and temporal differences in sedimentation (flux and sediment characteristics) to the 

reefs, and identify potential drivers (e.g., precipitation, wave height). 

3.	 Quantify how organic and inorganic contaminants in surface sediments and coral tissues mustard hill 

coral vary spatially across the study area, and how the magnitudes of those concentrations compare to 

previously published sediment quality guidelines and regional/national historic values. 

4.	 Determine the spatiotemporal variability in surface water nutrient concentrations in the watershed, bay 

and reef systems, including the relationship with land use and precipitation. 

These data will serve as a baseline with which to compare potential changes following restoration of the Guánica Bay 

watershed. In future years, follow up assessments will be necessary to track these changes, and determine the efficacy 

of management efforts. 
Baseline Assessment of Guanica Bay, Puerto Rico in Support of Watershed Restoration

4 Introduction

RefeRenCes 

Bauer, L.J., K. Edwards, K.K.W. Roberson, M.S. Kendall, S. Tormay, and T.A. Battista. 2012. Shallow-water benthic habitats of Southwest Puerto Rico. NOAA Technical Memorandum NOAA NOS NCCOS 155. Silver Spring, MD. 

Bryant, D., L. Burke,J. McManus, M. Spalding. 1998. Reefs at Risk: A Map-based Indicator of Threats to the World’s Coral Reefs. World 

Resources Institute, Washington, DC.. 

Burke, L. and J. Maidens. Reefs at risk in the Caribbean. 2004. World Resources Institute. Washington, D.C. 

Caribbean Fishery Management Council (CFMC). 1998. Essential fish habitat (EFH) generic amendment to the fisheries management 

plans (FMPs) of the U.S. Caribbean including a draft environmental Assessment: Volume 1. San Juan, PR. 

Costanza, R. R. d’Arge, R. de Groot, S. Farber, M. Grasso, B. Hannon, K. Limburg, S. Naeem, R. V. O’Neill, J. Paruelo, R. G. Raskin, 

P. Sutton, and M. van den Belt. 1997. The value of the world’s ecosystem services and natural capital. Nature. 387: 253-260. 

Cramer, V. and Hobbs, R. 2007. Old fields: Dynamics and Restoration of abandoned farmland. Island Press, Washington, D.C. 

Center for Watershed Protection (CWP). 2008. Guanica Bay Watershed Management Plan. NOAA Coral Reef Program and DRNA, 

Puerto Rico. http://www.cwp.org/online-watershed-library/cat_view/64-manuals-and-plans/81-watershed-management-plansand-guidance 

Commonwealth of Puerto Rico and NOAA Coral Reef Conservation Program. 2010. Puerto Rico’s Coral Reef Management Priorities. 

NOAA. Silver Spring, MD.. 

Dixon, J. A. 1998. Economic values of coral reef: what are the issues?” in Hatziolos, M.E., et al. (eds.) Coral reefs: challenges and opportunities for sustainable management. World Bank, Washington, pp. 157–162. 

Fabricius, K.E.. 2005. Effects of terrestrial runoff on the ecology of corals and coral reefs: review and synthesis. Mar. Poll. Bull. 50: 

125–146. 

Kendall, M.S., C.R. Kruer, K.R. Buja, J.D. Christensen, M. Finkbeiner, M.E. Monaco. 2011. Methods used to map benthic habitats of 

Puerto Rico and the US Virgin Islands. National Oceanic and Atmospheric Administration, National Ocean Service, Biogeography Team 

Technical Report, Silver Spring, MD. 

Larsen, M.C. and A. Santiago-Román. 2001. Geomorphic Processes and Riverine Habitat Mass wasting and sediment storage in a 

small montane watershed: an extreme case of anthropogenic disturbance in the humid tropics. American Geophysical Union Monograph Series. 

Larsen, M.C. and R.M. Webb. 2009. Potential Effects of Runoff, Fluvial Sediment, and Nutrient Discharges on the Coral Reefs of 

Puerto Rico. Journal of Coastal Research. 25:189-208. 

Moberg, F. and C. Folke. Ecological goods and services of coral reef ecosystems. Ecological Economics 1999. 29: 215-233. 

Pait, A.S., D.R. Whitall, C.F.G. Jeffrey, C. Caldow, A.L. Mason, G.G. Lauenstein, and J.D. Christensen. 2008. Chemical contamination 

in southwest Puerto Rico: an assessment of organic contaminants in near shore sediments. Mar. Poll. Bull. 56:580-606. 

Pait, A.S.,C.F.G Jeffrey, C. Caldow, D.R. Whitall, S.I. Hartwell, A.L. Mason and J.D. Christensen. 2009. Chemical Contaminants in the 

Coral Porites astreoides from Southwest Puerto Rico. NOS NCCOS 91. NOAA/NOS/Center for Coastal Monitoring and Assessment. 

Silver Spring, MD. 

Perfecto, I., R.A. Rice, R. Greenberg, R. and M.E. Van der Voort. 1996. Shade Coffee: A Disappearing Refuge for Biodiversity. BioScience. 46: 598-608. 

Pittman, S.J. , S.D. Hile, C.F.G. Jeffrey, R. Clark, K. Woody, B.D. Herlach, C. Caldow, M.E. Monaco, and R. Appeldoorn. 2010. Coral 

reef ecosystems of Reserva Natural La Parguera (Puerto Rico): Spatial and temporal patterns in fish and benthic communities (2001-

2007). NOAA Technical Memorandum NOS NCCOS 107. Silver Spring, MD. 

Sotomayor-Ramírez, D. and L. Pérez-Alegría. 2011. An assessment of agricultural activities in the eastern portion of the Lajas Valley 

Agricultural Reserve, within Lajas and Guánica municipalities. University of Puerto Rico, Mayagüez, Agricultural Experiment Station, 

Unpublished Manuscript. 16 pp, with appendices. 

U.S. Census Bureau. (2003). U.S. Census Bureau http://www.census.gov/popest/archives/2000s/vintage_2002/PRM-EST2002-01. 

html 

U.S. Coral Reef Task Force. 2011. U.S. Coral Reef Task Force Resolution 25.1. http://www.coralreef.gov/meeting25/pdf/resolution.pdf 

Warne, A.G., R.M.T. Webb, M.C. Larsen. Water, sediment, and nutrient discharge characteristics in rivers of PR and their potential 

influence on coral reefs. USGS Sci. Inv. Report 2005-5206. Reston, VA. 2005. 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

5 Fish and Benthic Communities 

Chapter 2: fish Communities and Associated benthic habitats 

in the guánica bay Region of southwest Puerto Rico 

Laurie Bauer1,2,3, Kimberly Edwards1,2 and Chris Caldow1 

bACkgRound 

The goal of this component of the baseline assessment is to provide a spatially-explicit characterization of fish and benthic 

communities in the marine ecosystem adjacent to Guánica Bay. The approach to characterizing the marine resources of 

the region included two complimentary components. Recently, an updated fine-scale benthic habitat map for southwest 

Puerto Rico, including Guánica Bay, was completed (Bauer et al., 2012). This marks the second such effort NOAA has 

conducted to map shallow water marine benthic habitats of this region. Components of the new mapping product that 

mark an improvement over NOAA’s previous digital maps (Kendall et al., 2001) include an expanded habitat classification scheme, smaller minimum mapping unit and more recent aerial imagery. In addition, within the extent used for this 

mapping effort, a larger total area was mapped than in the previous mapping effort. For example, some areas that were 

mapped as unknown in the previous effort were able to be delineated in the new map due to better remote sensing imagery. 

Southwest Puerto Rico is represented by a diverse array of benthic habitats. The spatial distribution of two of the mapped 

attributes, major geomorphological structure type and dominant biological cover, are displayed in Figures 2.1 and 2.2. 

Unconsolidated sediments (sand and mud) are most common in the nearshore environment, including Guánica Bay and 

the La Parguera lagoon (Figure 2.1). Portions of the protected shoreline and offshore cayes are lined with mangroves. 

Seagrass beds of various patchiness levels are also common in the nearshore areas (Figure 2.2). An extensive reef complex, a mix of both low rugosity (e.g., pavement) and high rugosity (aggregate reef, spur and groove) hardbottom, ranges 

the entire length of the bank-shelf in southwest Puerto Rico. Algae, which includes both macroalgae and turf algae, was 

most often the dominant biological cover on coral reef and hardbottom habitats. While live coral was rarely mapped as the 

major cover, there were exceptions. High density finger coral (Porites porites) fields were occastionally present in back 

reef/reef flat environments, including south of Cayos de Caña Gorda. 

The new benthic habitat map serves as a current snapshot of the extent of marine benthic habitats in the region and will 

support the management and conservation of the watershed and coastal marine waters of Guánica and greater southwest Puerto Rico. Future mapping of southwest Puerto Rico can be used to monitor changes in the benthic habitats in the 

La Parguera/Guánica region following restoration efforts in the Guánica Bay watershed. One of the major goals of these 

restoration efforts is to reduce input of sediments, nutrients and contaminants into the marine environment. Reduction in 

these terruginous inputs could have several potential effects on the marine habitats. For example, improved water clarity 

would likely benefit growth of seagrass and corals. 

Figure 2.1. Detailed geomorphological structure in the Guánica/La Parguera study area (Bauer et al., 2012). 

1. NOAA/NOS/NCCOS/ CCMA Biogeography Branch

2. CSS-Dynamac, Fairfax, VA 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Fish and Benthic Communities 

67°9'0"W 67°6'0"W 67°3'0"W 67°0'0"W 66°57'0"W 66°54'0"W 66°51'0"W 

17°51'0"N 17°54'0"N 17°57'0"N

Biological Cover 

20 2.5 5 

Kilometers 

10 

Algae, Continuous (90% - 100%) 

Algae, Patchy (50% - <90%) 

Algae, Patchy (10% - <50%) 

Live Coral, Continuous (90% - 100%) 

Live Coral, Patchy (50% - <90%) 

Mangrove, Continuous (90% - 100%) 

Mangrove, Patchy (50% - <90%) 

67°9'0"W 67°6'0"W 67°3'0"W 67°0'0"W 66°57'0"W 

Mangrove, Patchy (10% - <50%)
 

No Cover, Continuous (90% - 100%)
 

Seagrass, Continuous (90% - 100%)
 

Seagrass, Patchy (50% - <90%)
 

Seagrass, Patchy (10% - <50%)
 

Unknown, Unknown
 

66°54'0"W 66°51'0"W 

17°51'0"N 17°54'0"N 17°57'0"N 

Figure 2.2. Major biological cover in the Guánica/La Parguera study area (Bauer et al., 2012). 

More details on the methods and classification scheme used to create the benthic habitat map can be found in Bauer et 

al. (2012). Here, we expand on the recent mapping efforts by presenting baseline data on fish and benthic communities. 

It is anticipated that additional monitoring will be conducted following the implementation of the restoration activities to 

assess potential changes in benthic cover, population estimates and size spectra of fish over time. 

Since 2001, the National Centers for Coastal Ocean Science (NCCOS) Biogeography Branch has worked to characterize, monitor and assess the status of the marine environment in neighboring La Parguera, Puerto Rico, located west 

(downstream) of Guánica Bay (Pittman et al., 2010). The area is designated as a natural reserve by the Puerto Rico 

Department of Natural and Environmental Resources. While it is important to characterize habitats and fish communities 

in close proximity to Guánica Bay, it is important to note that the La Parguera region is, with respect to circulation patterns and pollutant transport, an extension of this same system. The prevailing surface currents are driven by the trade 

winds and flow westward, meaning that effluent from Guánica Bay flows downstream towards La Parguera. Hence, the 

La Parguera region likely serves as a sink for land-based sources of pollution discharged from Guánica Bay. Due to this 

oceanographic connectivity, the La Parguera region was also included in this assessment and potential differences between the two regions were explored. 

The objectives of this assessment are to: 

1. Characterize fish and benthic communities of the Guánica Bay region. This data will serve as a baseline with 

which to compare potential changes following restoration of the Guánica Bay watershed. 

2. Compare fish and benthic community metrics in the Guánica Bay study area with the neighboring La Parguera study area. 

methods 

Site Selection 

Using NOAA’s established Coral Reef Ecosystem Monitoring protocols (e.g., Pittman et al., 2008 and 2010), field surveys 

were conducted in August 2010 to characterize the fish communities and associated habitats in the Guánica Bay marine 

ecosystem. Sites were selected using a random-stratified survey design with habitat type (coral reef and hardbottom, 

unconsolidated sediments, mangrove) and geographic region (west, central, east of Guánica) as the main strata. The 

geographic strata were previously designated by the NCCOS COAST Branch for nutrient and contaminant sampling 

(Chapters 3 and 4). The eastern most strata is located upstream of the Guánica Bay outlet, while the central and western 

strata are located downstream of the bay (Figure 2.3). Although sample size in the initial baseline assessment was not 

large enough to make robust statistical comparisons between the three regions, they are noted here for consistency with 

COAST’s complimentary sampling efforts and will be used for qualitative descriptions of patterns across the study region. 

As more surveys are conducted over time, the increased sample size will enable more comprehensive statistical comparisons between the three geographic strata. 

Guánica Bay itself was not included in the survey area due to poor visibility, rendering it unsuitable for visual survey methods. To effectively survey fish using the underwater visual methods, it is necessary that the divers have a minimum of 2 

m visibility. During previous dives within the bay, it was determined that visibility was consistently below this threshold. 

6 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

7 Fish and Benthic Communities 

 

La Parguera 

Guanica 

(West) 

Guanica 

(Central) 

Guanica 

(East) 

Coral Reef and Hardbottom 

Unconsolidated sediment 

Mangrove 

Guanica 

La Parguera 2 Not surveyed 0 1.5 3 6

Kilometers 

Figure 2.3. Guánica and La Parguera study areas and benthic habitat strata used to stratify surveys of benthic habitat composition, 

fish communities and marine debris. 

The number of sites selected within each strata was determined based on logistics and results from statistical analyses 

of variance (Menza et al., 2006). As the new benthic habitat map (Bauer et al., 2012) was not completed at the time, the 

previous NOAA benthic habitat map (Kendall et al., 2001) was used as the basis for site stratification. The “coral reef and 

hardbottom” strata comprised bedrock, pavement, rubble and coral reef, while the “unconsolidated sediments” stratum 

comprised submerged aquatic vegetation, as well as uncolonized sand and mud. The “mangrove” stratum comprised the 

seaward edge of mangrove habitat able to be surveyed with these visual underwater survey methods. 

This designated Guánica study area outlined above overlaps with the La Parguera study region that has been monitored 

since 2001 (Pittman et al., 2010). Data from the La Parguera region considered for this report includes data collected 

in both August of 2010 and in the previous two summer missions (August 2008-2009). Data from winter missions were 

not considered as several metrics exhibit seasonal variation (Pittman et al., 2010). For the purposes of this report, the 

“overlap” area will be considered part of the Guánica Bay study region. The La Parguera study area will refer only to the 

area west of the Guánica study area boundary (Figure 2.3). Data collected prior to 2008 was summarized in Pittman et 

al. (2010). 

Field methods 

The surveys of benthic habitats, fish communities, marine debris and macroinvertebrates were conducted within a 25x4 m 

transect (100 m2

), along a random heading. 

Two divers performed the survey at each 

site (Figure 2.4a-c). One diver was responsible for visual counts and size estimation 

of fish species. The second diver quantified 

benthic habitat composition, macroinvertebrates and marine debris. These established monitoring protocols have been used 

monitor La Parguera and other locations 

within NOAA’s Caribbean Coral Reef Ecosystem Monitoring Project (Pittman et al., 

2008; Pittman et al., 2010). The standardized protocols allow for comparisons to be 

a) b) 

0 4 m 

c) c) 

5 10

Transect tape 

15 20 25 m

1-m2 quadrat 

5 m 

made between different areas. In addition, Figure 2.4a-c. Divers collecting data on a) habitat and b) fish composition, and c) 

the protocols include measurement of nu- schematic representation of the placement of the 1 m2 quadrat along a 25 m tranmerous variables that would be of interest sect tape during fish and benthic community surveys.

to monitor over time to evaluate changes 

following the reduction in the input of land-based sources of pollution to the marine environment. 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Fish and Benthic Communities 

Benthic Habitat Composition 

The habitat diver first assigned an over- Table 2.1. Abiotic and biotic variables measured in five quadrats along fish tranall bottom type (i.e., hardbottom, unconbenthic Variables measurements 

Cover

 (%) 

height 

(cm) 

Abundance

 (#) 

Abiotic

Hardbottom X X

Sand X

Rubble X

Fine sediment/silt X

Rugosity

Water depth 

Biotic

Corals (by species) X

Macroalgae X X

Seagrass (by species) X X

Gorgonians

Sea rods, whips and plumes X X X

Sea fans X X X

Encrusting form X

Sponges

Barrel, tubes, rope, vase X X X

Encrusting form X

Other benthic macrofauna

Anemonies and hydroids X X

Tunicates and zoanthids X

Mangroves

Prop roots X

Prop roots colonized by algae X

Prop roots colonized by sponges X

Prop roots colonized by other biota X 

sects. 

solidated sediments or mangrove) to each 

transect based on in situ observation. Data 

on the percent cover of abiotic and biotic 

composition at each survey site were recorded within five 1 m2 quadrats placed 

randomly along the 25x4 m transect so that 

one quadrat falls within every 5 m interval 

along the transect. The quadrat was placed 

at each randomly chosen meter mark and 

systematically alternated from side to side 

along the transect tape (Figure 2.4c). Several variables were measured to characterize benthic composition and structure 

(Table 2.1). The quadrat was divided into 

100 smaller 10x10 cm squares with string 

(1 small square = 1% cover) to help the 

diver with estimation of percent cover. Percent cover was determined by looking at the 

quadrat from above and visually estimating 

percent cover in a two-dimensional plane. 

The information recorded included: 

Abiotic cover - the percent cover (to the 

nearest 1%) of four abiotic substrate categories (hardbottom, sand, rubble, fine sediments/silt) was estimated within each 1 m2 

quadrat. The maximum height of the hardbottom was also measured. 

Biotic cover - the percent cover (to the nearest 0.1%) of algae, seagrass, live corals, 

sponges, gorgonians and other biota was 

estimated within each 1 m2 quadrat. Taxa 

were identified to the following levels: stony 

coral-species, seagrass-species, algaemorphological group, sponge-morphological group and gorgonians-morphological 

group (Table 2.1). For stony and fire corals, the percentage of bleached coral and 

diseased/dead coral was estimated to the 

nearest 0.1%. In addition, the presence of 

elkhorn coral (Acropora palmata) or staghorn coral (A. cervicornis) either within the transect area (100 m2) or the vicinity 

of the sample site was also noted by the divers. 

Maximum canopy height - the maximum height of sponges, gorgonians and soft algal groups was recorded to the nearest 

1 cm in each quadrat. 

Number of individuals - the number of individual upright sponges, gorgonians, non-encrusting anemones and non-encrusting hydroids was recorded in each quadrat. 

Rugosity – for hardbottom sites, rugosity was measured by placing a 6 m chain at two randomly selected positions, ensuring no overlap, along the 25 m belt transect. The chain was positioned along the centerline of the transect such that it followed the substrate’s relief. The straight-line horizontal distance covered by the chain was measured. An index of rugosity 

(R) was calculated as the ratio of contoured surface distance (d) to linear distance (L = 6m) using R=1−d/L. 

Mangrove Habitat Data 

At mangrove sites, the survey was conducted along the edge of the mangrove canopy. The transect was laid out as close 

to the prop roots and as far into the mangroves as possible, up to 2 m, and then out to the edge of the mangrove overhang 

such that the total area surveyed was still 100 m2

. In this case, some of the survey sites fell on seagrass habitat. This is 

allowed as the mangrove habitat is defined as a transition zone habitat. Habitat metrics above were collected along with 

additional mangrove data, including: number of prop roots, number of prop roots colonized by algae, number of prop roots 

colonized by sponges and number of prop roots colonized by other biota (tunicates, anemones, zooanthids, etc.). 

8 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

9 Fish and Benthic Communities 

Macroinvertebrate Counts 

The habitat diver counted the abundance of spiny lobsters (Panulirus argus), long-spined urchins (Diadema antillarum) 

and the abundance/maturity of queen conchs (Strombus gigas) within the 25x4 m transect at each site. The maturity of 

each conch was determined by the presence (mature) or absence (immature) of a flared lip. 

Fish Census 

Fish surveys were conducted along the 25x4 m transect (100 m2) using a fixed survey duration (15 minutes) regardless of 

habitat type or complexity. The number of individuals per species was recorded in 5 cm size class increments up to 35 cm 

using visual estimation of fork length. If the individual could not be identified to species, they were identified to the extent 

possible (i.e., genus or family). Individuals greater than 35 cm were recorded as an estimate of the actual fork length to 

the nearest centimeter. 

Marine Debris 

The number and type of marine debris within the 100 m2 transect were recorded. Marine debris size and the area of habitat it affected were estimated. Any flora or fauna that were colonizing the debris item were noted. 

dAtA AnAlYsis 

Benthic Habitat 

While many benthic variables were measured during the surveys, data analyses for this report focused primarily on describing differences among major habitat types and broad-scale spatial patterns in the percent cover of the sessile biotic 

components as described in Table 2.1. Quadrat measurements along each transect were averaged and cumulative coral 

species richness was calculated for each site. Average site values were used to calculate means and standard errors 

of measured variables for each habitat type (coral reef and hardbottom, unconsolidated sediment, mangrove) and study 

area (La Parguera, Guánica) combination. In addition, data were plotted in ArcGIS (v9.3, ESRI) to examine broad spatial 

patterns in the benthic cover variables. For the above analyses and summary statistics, all 2008-2010 data from within 

the La Parguera study area were used to provide a detailed site characterization. 

Select habitat metrics were tested to identify potential differences between the Guánica and La Parguera study areas. For 

these tests, a random subset of sites within the La Parguera study area was selected so that the sample size for each bottom type was equal to that of the Guánica study area. Prior to this analysis, we tested the assumption that benthic cover 

metrics did not differ significantly over the three years of the La Parguera dataset. As the majority of metrics did not vary 

significantly over this time period, we determined that using a subset of data for statistical tests would not introduce significant bias into the analysis. As the assumption of normality was not met for most variables, non-parametric WilcoxonMann-Whitney tests were used to test differences between study areas (SAS v9.1.3.) Tests were conducted separately for 

individual strata, as hardbottom, mangrove and unconsolidated sediments generally have distinct benthic communities. 

Further analysis was used to explore possible connections between coral variables and the distance from the mouth of 

Guánica Bay. The in-water distance between each survey location and the bay mouth was calculated using the cost distance raster tool in ArcGIS. Because assumptions of normality could not be met a Spearman’s nonparametric correlation 

test was used to test for associations between distance and percent live coral cover, coral species richness and percent 

gorgonian cover. 

Fish Assemblages 

A summary table of all species observed in this characterization across the entire sampling domain was created (see 

Appendix A, Table A.1). Habitat-wide estimates for community metrics (total density, total biomasss, species richness, 

Shannon diversity, and density and biomass of trophic groups) were computed for the Guánica and La Parguera study 

areas employing methods described by Cochran (1977)1

. Percent occurrence, mean density and biomass (per 100 m2) 

and corresponding standard errors (SE) were calculated for each species. Trophic groups include piscivores, herbivores, 

invertivores and zooplanktivores and were defined for each species based on diet information from Randall (1967). It is 

important to note that these groups are not mutually exclusive because many fish species can be classified into two or 

more of these groups based on diet. In those circumstances the trophic group was assigned based on the dominant diet 

component. Biomass was calculated using published length-weight relationships based on the formula: 

W = aLb, 

where L is length in centimeters and W is weight in grams. The midpoint of each size class was used for L values, and 

the actual length was used for fish >35 cm. For fish in the 0-5 cm size class, 3 cm was used as the mid-point because we 

do not typically observe fish <1 cm. Values for the a and b coefficients were obtained from FishBase (Froese and Pauly, 

2008). Biomass for species with no published length-weight relationships was calculated using terms for the closest congener with most similar morphology. 

1

Small baitfish (i.e., Families Atherinidae, Clupeidae) were omitted from the analysis when calculating overall mean density and biomass and in testing differences between total density and biomass as occasional large schools of small baitfish can highly skew density 

and biomass estimates in mangrove habitat. 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

10 Fish and Benthic Communities 

Species diversity was calculated using the Shannon Index (H’), a measure that incorporates both richness and evenness: 

H’ = Σipi(logepi) 

where pi is the relative abundance of each species. 

Data were plotted in ArcGIS to examine broad spatial patterns in the fish metrics. In addition, select families and species 

of commercial and/or ecological interest were selected for further examination. For each species/family, a summary of the 

species distribution, size frequency, and mean density and biomass by habitat type and study area was calculated. Age 

class (juveniles/sub-adults and adult) was identified based on mean length at maturity as identified by FishBase (Froese 

and Pauly, 2008), García-Cagide et al. (1994) and Ault et al. (2008). Where length at maturity was unknown, one-third of 

maximum size was used as a proxy as in Pittman et al. (2008, 2010). For the above analyses and summary statistics, all 

2008-2010 data from within the La Parguera study area were used to provide a detailed site characterization. 

Community metrics and the select families/species were compared between the Guánica and La Parguera study area by 

habitat type to characterize any potential differences between the two regions1. As in the benthic habitat analysis, we ran 

a preliminary analysis to test whether fish species metrics varied significantly by years within the La Parguera dataset. 

For the majority of species, no significant differences among years were detected. Consequently, the previously selected 

random subset of sites within the La Parguera study area was used so that the sample size for each bottom type was 

equal to that of the Guánica study area. As the assumption of normality was not met for most variables, non-parametric 

Wilcoxon-Mann-Whitney tests were used to test differences between study areas (SAS v9.1.3). 

Differences and similarities in species composition were further examined using multivariate statistical techniques (Primer 

v.6; Clarke and Warwick, 2001). Data were square-root transformed prior to analysis, and one outlier site was removed 

due to extremely low fish abundance (n=1 fish). Data were arranged in a species abundance by site data matrix, which 

was used to construct a triangular matrix of the percentage similarity in community composition between all pairs of sites 

using the Bray-Curtis Coefficient. The coefficient is a measure of how similar samples are to each other, ranging from 0% 

(complete dissimilarity) to 100% (complete similarity). Next, non-metric multidimensional scaling (nMDS) was used to 

place samples in a two-dimensional configuration such that the rank order of the distances between the samples agreed 

with the rank-order of the similarities from the Bray-Curtis matrix. Sites were coded by bottom type and geographic study 

area (La Parguera, Guánica) for examination of visual patterns of similarities between sites. These factors were also used 

to test for significant differences in similarity using Analysis of Similarities (ANOSIM), a multivariate, non-parametric version of ANOVA. 

Results And disCussion 

Benthic Habitat 

Abiotic Composition 

Within the Guánica study area, a total of 61 

sites were surveyed: 30 on hardbottom, 22 

on unconsolidated sediments and nine in 

mangrove (Figure 2.5). Three sites identified as hardbottom based on habitat maps 

(Kendall et al., 2001) were designated as 

unconsolidated sediment by the survey 

diver and were subsequently grouped with 

the unconsolidated sediment surveys in the 

data analysis. 

A total of 188 sites were surveyed during 

the summer seasons of 2008-2010 in the 

La Parguera study area, and were comprised of the following: 97 hardbottom, 67 

unconsolidated sediments and 24 mangrove (Figure 2.5). Nine sites originally 

stratified as hardbottom were designated 

as unconsolidated sediment by the diver, 

and were subsequently grouped with the 

unconsolidated sediment surveys in the 

data analysis. Conversely, one site stratified 

as an unconsolidated sediment was designated as hardbottom by the diver and was 

subsequently grouped with the hardbottom 

surveys in the analysis. 

Figure 2.5. Site locations of surveys of benthic habitat composition, fish communities and marine debris. Data include the August 2010 survey in the Guánica study 

area (N=61) and August 2008-2010 surveys in the La Parguera study area (N=188). 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Fish and Benthic Communities 

Figure 2.6. Mean (±SE) percent cover of abiotic substrate across hardbottom, unconsolidated sediment, and mangrove surveys in the a) Guánica and b) La Parguera study areas. 

0.0 

10.0 

20.0 

30.0 

40.0 

50.0 

60.0 

70.0 

80.0 

90.0 

100.0 

Hardbottom Rubble Sand Fine sediment 

Percent cover 

Hardbottom Unconsolidated Sediment Mangrove 

0.0 

10.0 

20.0 

30.0 

40.0 

50.0 

60.0 

70.0 

80.0 

90.0 

100.0 

Hardbottom Rubble Sand Fine sediment 

Percent cover 

Hardbottom Unconsolidated Sediment Mangrove 

a) 

b) 

Abiotic composition varied across habitat types but were similar between the two 

study areas of similar habitat types. (Figure 

2.6a and b). Surveys conducted on hardbottom habitat in both the Guánica and La 

Parguera study areas were predominantly 

composed of hard substrate, or hardbottom, 

with small amounts of rubble and sand present, and were devoid of fine sediments. The 

majority of surveys conducted on unconsolidated sediment habitat were dominated 

by sand and fine sediment. Hardbottom or 

rubble substrates were recorded during a 

few unconsolidated sediment surveys in the 

Guánica (n=3 of 22) and and La Parguera 

study areas (n=6 of 67). Most mangrove 

sites were characterized by sand and fine 

sediments, with occasional small amounts 

of rubble. 

Biotic Composition Overview 

Here broad information on the habitat 

groups in both study areas are examined. 

In subsequent sections, variability of species composition, cover, and diversity within 

and among habitat groups are covered in 

more detail. Among hardbottom sites (Figure 2.7a), algae accounted for the highest 

mean percent cover in the Guánica study 

area (mean ± SE: 65.3 ± 4.2%), followed 

by soft corals (3.6 ± 1.0%), sponges (3.4 ± 

0.5%) and hard coral (2.2 ± 0.4%). Bare, uncolonized substrate averaged 25.0 ± 4.8%. 

Algae also accounted for the highest mean 

percent cover in the La Parguera study area 

(61.1 ± 2.2%), followed by soft corals (6.0 

± 0.8%), hard corals (4.0 ± 0.4%) and low 

amounts of sponges (2.0 ± 0.2%). Similar to 

the Guánica study area, bare, uncolonized substrate averaged 26.0± 2.4%. 

Unconsolidated sediment sites (Figure 2.7b) were characterized by an assemblage of submerged aquatic vegetation and 

low levels of benthic fauna. Seagrass accounted for the highest mean percent cover among the unconsolidated sediment 

sites in the Guánica study area (8.2 ± 3.2%), followed by algae (5.2 ± 1.2%). All remaining benthic groups surveyed were 

present in low amounts (<1%). Bare substrate averaged 86.4 (±3.4%). Within the La Parguera study area unconsolidated 

sediment surveys, seagrass (17.4 ± 2.5%) and algae (12.4 ± 2.1%) also dominated the benthos, with the remaining categories in low amounts as seen in the Guánica study area. Bare substrate averaged 69.4 (± 3.0%). 

Algae was the dominant benthic cover on substrates in mangrove habitat within the Guánica study area (Figure 2.7c; 57.4 

± 10.9%) with variable amounts of seagrass present (3.6 ± 2.0%). Bare substrate averaged 38.5 (± 10.9%). Similarly, in 

mangrove surveys within the La Parguera study area, algae was the dominant cover type (63.0 ± 5.9%), followed by low 

amounts of seagrass (0.8 ± 0.5%). Bare substrate averaged 35.8 (± 5.7%). 

Hard Coral Composition 

Percent scleractinian coral in the Guánica study area ranged from 0-10.76% (Figure 2.8). The site with the highest coral 

cover was located nearshore in 5 meters of water, while sites with moderate cover (3.1-6%) were located almost exclusively in the deeper waters of the outer shelf. The coral community in the Guánica study area was comprised of 21 species, with species richness varying from 0-10 species/site (Figure 2.9). Located on the outer reef edge, the site with the 

highest coral species richness (10 species/site) had low-moderate coral cover. Within hardbottom surveys, massive starlet coral (Siderastrea siderea) represented the species of highest coral cover (0.5 ± 0.1%) followed by mustard hill coral 

0.4 ± 0.1%, Figure 2.10a and Figure 2.11). All other species observed averaged <0.3% cover (Figure 2.10a). Bleached 

coral was present in small amounts (≤0.1%) in one-fifth (six out of 30) of the surveys in hardbottom habitat. Reef rugosity 

measured on hardbottom sites ranged from 0-0.42, averaging 0.05 (± 0.01). Sites with the highest values were generally 

located on offshore reefs near the shelf edge and on sloping fore reefs seaward of the lagoon (Figure 2.12). 

11 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Fish and Benthic Communities 

Within the La Parguera study area, percent 

scleractinian coral ranged from 0-18.5% 

(Figure 2.8). Coral cover generally increased with distance from shore. The site 

with the highest coral cover (18.5%) was 

located on the outer shelf in 22 meters of 

water. Over the three years considered in 

this analysis (2008-2010), 37 species were 

recorded within the La Parguera study area, 

with species richness ranging from 0-12 

species/site (Figure 2.9). The boulder star 

coral (Montastrea annularis) complex was 

the dominant scleractinian species in the 

La Parguera study area (1.4 ± 0.2%), while 

all remaining species observed averaged 

<0.5% cover (Figure 2.10b). Little incidence 

of bleached coral was reported (mean ± SE 

= 0.01 ± 0.0%). Reef rugosity averaged 0.20 

(± 0.02) and ranged from 0-0.47, with higher 

values located on mid-outer shelf reefs (Figure 2.12). 

On hardbottom habitats, percent cover of 

scleractinian coral and coral species richness were significantly greater in the La Parguera study area compared to the Guánica 

study area (Table 2.2). Further, percent live 

coral cover was significantly correlated with 

distance from the mouth of Guánica Bay 

(Spearman’s Rho=0.19, p=0.036). Coral 

species richness also showed a positive 

correlation with increasing distance from the 

bay, but the statistical significance for this 

metric was marginal (Speaman’s Rho=0.16, 

p=0.068). Reef rugosity did not vary significantly between the two study areas. Figure 2.7. Mean (±SE) percent cover of major cover groups in a) hardbottom habitat, b) unconsolidated sediment habitat and c) mangrove habitats in Guánica and 

La Parguera study areas. 

0 

10 

20 

30 

40 

50 

60 

70 

80 

Percent cover 

A) hardbottom Guanica 

Parguera 

0 

10 

20 

30 

40 

50 

60 

70 

80 

Percent cover 

C) mangrove 

Guanica 

Parguera 

0 

10 

20 

30 

40 

50 

60 

70 

80 

Percent cover 

b) unconsolidated sediments 

Guanica 

Parguera 

12 

Figure 2.8. Percent cover of scleractinian corals. 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Fish and Benthic Communities 

Figure 2.9. Coral species richness. 

Staghorn coral and elkhorn coral 2 

are each listed as threatened coral a) 1.8 

1.6 species under the Endangered 

Species Act (USFWS, 1973). 

Mean cover of both species was 

estimated at <1% within both study

areas. In the Guánica study area, 

Percent cover 

1.4 

1.2 

1 

0.8 

0.6 

elkhorn coral was present in the 0.4 

0.2 

quadrat survey at one site and was 

not reported from any additional 

sites, while staghorn coral was 

present in two quadrat surveys 

and noted within the vicinity at two 

additional sites. In the La Parguera 

study area, only staghorn coral 

was observed. This species was 

recorded within quadrats at four 

surveyed sites and was observed 

anecdotally in the surrounding area 

of an additional two survey sites. It 

is important to note that this study’s 

0 

Guanica Coral Species-hardbottom habitat only 

b) 2 

1.8 

1.6 

1.4 

1.2 

Percent cover 

methods were not designed specifically to detect Acropora species. 

1 

0.8 

0.6 

0.4 

Hydrocorals (Millepora sp.) and 0.2 

other invertebrates (see Table 2.1) 0 

were present in low amounts in 

both study areas (<0.3%). Zoanthid cover was primarily limited to 

hardbottom sites in both study areas with the highest mean cover 

observed on the mid-shelf reefs 

of the La Parguera study area and Parguera Coral Species-hardbottom habitat only 

Figure 2.10. Mean (±SE) percent cover of scleractinian coral species in the a) Guánica study on a nearshore forereef site near area and b) La Parguera study area. Playa Santa within the Guánica 

study area (Figure 2.13). Zooanthid cover averaged 0.4 (± 0.02)% on hardbottom within the Guánica study area and 0.5 (± 0.01)% in the La Parguera study area. 

13 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

14 Fish and Benthic Communities 

Figure 2.11. Coral species observed in the surveys in southwest Puerto Rico. From left to right: elkhorn coral, boulder star coral complex, pillar coral and mustard hill coral. 

Figure 2.12. Mean rugosity (hardbottom sites only). 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Fish and Benthic Communities 

Table 2.2. Results of nonparametric analysis (Wilcoxon-Mann Whitney) for benthic habitat metrics between the Guánica and La Parguera study area. As described in the methods, a random subset of the La Parguera (2008-2010) dataset was used. An asterisk (*) 

Indicates a significant difference at the α=0.05 level. 

hardbottom 

metric Z p-value 

% Live coral 2.37 0.018* 

Coral species richness 1.99 0.046* 

% Gorgonians 2.52 0.011* 

% Sponge -2.59 0.010* 

% Macroalgae -0.82 0.412 

% Turf algae -2.17 0.030* 

% Crustose/coralline algae (CCA) -0.90 0.370 

% Filamentous algae/Cyanobacteria 3.82 <0.001* 

% Zooanthids -0.51 0.611 

Rugosity 0.68 0.499 

unconsolidated sediment 

metric Z p-value 

% Sponge 2.45 0.014* 

% Seagrass 2.09 0.037* 

% Macroalgae 1.44 0.149 

% Filamentous algae/Cyanobacteria -1.14 0.253 

mangrove 

metric Z p-value 

% Seagrass -0.90 0.366 

% Macroalgae 0.27 0.791 

% Filamentous algae/Cyanobacteria 0.18 0.860 

Figure 2.13. Percent cover of zooanthids. 

15 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

16 Fish and Benthic Communities 

Gorgonian Composition 

Gorgonian cover ranged from 0-24.6% in the Guánica study area (Figure 2.14). Sea plumes/rods/whips were the dominant gorgonian morphological cover across hardbottom surveys (2.6 ± 0.6%), followed by sea fans (0.6 ± 0.3%), and 

encrusting gorgonians (0.3 ± 0.2%). Highest cover was observed both at a nearshore location on fore reef, as well as 

offshore near the shelf edge. 

Gorgonian cover ranged from 0-57.8% in the La Parguera study area (Figure 2.14). Sites on aggregate reef adjacent to 

the cays within the mid shelf region of the La Parguera study area exhibited the highest gorgonian cover. Sea plumes/ 

rods/whips were the dominant gorgonian morphological cover on hardbottom sites (4.3 ± 0.7%), followed by encrusting 

gorgonians (1.0 ± 0.2%) and sea fan (0.7 ± 0.2%). 

Gorgonians were rarely observed on soft bottom or mangrove habitats so further investigation was conducted only with 

hardbottom sites. Results of the Wilcoxon-Mann-Whitney test indicate that total gorgonian cover was significantly greater 

on hardbottom in the La Parguera study area (Table 2.2). Further, gorgonian cover was positively correlated with distance 

from the mouth of Guánica Bay (Spearman’s Rho=0.21, p=0.017). 

Figure 2.14. Percent cover of gorgonians. 

Sponge Composition 

Sponge cover ranged from 0-13.3% in the Guánica study area, with the highest values on offshore hardbottom sites 

(Figure 2.15). Barrel/tube/vase sponge morphology accounted for the majority of sponge cover on hardbottom sites (2.3 

± 0.4%), followed by encrusting sponge (1.0 ± 0.2%). On unconsolidated sediment sites, each sponge morphology was 

present in very low amounts (<1%). 

Sponge cover ranged from 0-11.6% in the La Parguera study area and did not exhibit distinctive spatial patterns (Figure 

2.15). Sites with the highest sponge cover were situated in both inshore and offshore locations. Barrel/tube/vase sponge 

morphology dominated on hardbottom (1.1 ± 0.01%), followed by encrusting sponges (0.9 ± 0.1%). 

On hardbottom, percent cover of sponges was significantly greater in surveys within the Guánica study area compared 

to La Parguera (Table 2.2). On unconsolidated sediments, the pattern was reversed, with higher cover within the La Parguera study area. 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

17 Fish and Benthic Communities 

Figure 2.15. Percent cover of sponges. 

Algae and Seagrass Composition 

Algae was present in virtually all survey transects in the Guánica study area in various morphological forms. Macroalgal 

cover ranged from 0-78.0% and was present across all habitats (Figure 2.16). The site with the highest macroalgal cover 

in the Guánica study area was a mangrove site east of Bahia Montalvo. Mean macroalgal cover was higher, but more 

variable, in mangrove (21.8 ± 10.6%) than hardbottom habitats (18.7 ± 3.1%), and overall low across unconsolidated 

sediment surveys (3.3 ± 0.8%). Turf algae was a ubiquitous component of the reef community, ranging from 0-89.2% and 

averaging 43.3 (± 4.2)% across hardbottom habitat (Figure 2.17). Crustose coralline algae (CCA) was typically present in 

small amounts (ranging from 0-10.8%) and was primarily observed at hardbottom sites further offshore in the outer shelf 

region (Figure 2.18). Filamentous algae/cyanobacteria generally exhibited highest cover in mangroves (Figure 2.19), 

averaging 35.3 (±11.7)% across mangrove surveys but only 1.4 (±0.3)% and 1.4 (±0.9)% across hardbottom and unconsolidated sediment surveys, respectively. 

Figure 2.16. Percent cover of macroalgae. 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

18 Fish and Benthic Communities 

Algal cover patterns were similar in the La Parguera study area. Macroalgae was distributed across all areas, with percent 

cover ranging from 0-84.8% (Figure 2.16). The site with the highest macroalgal cover was a mangrove site west of the La 

Parguera waterfront. Macroalgal cover averaged 20.1 (± 2.2)% across hardbottom surveys, with more moderate amounts 

in mangrove and unconsolidated sediment habitats (10.5 ± 3.0% and 9.4 ± 1.9%, respectively). Turf algae ranged from 

0-80.8% and averaged 31.7 (± 2.5%) across hardbottom surveys (Figure 2.17). CCA was primarily restricted to hardbottom habitat (Figure 2.18), where it ranged from 0-9.4% and averaged 1.5 (±0.2)%. Cover values in the higher end of the 

range were generally located on the mid-outer shelf. Filamentous algae/cyanobacteria ranged from 0-99.4% and were 

most common in mangrove surveys, but there were occasionally moderate amounts on hardbottom (Figure 2.19). Mean 

cover was 51.1 (±7.0)% in mangrove, 7.8 (±1.3)% on hardbottom and 0.9 (±0.4)% on unconsolidated sediments. 

There were two notable differences in algal cover between the two study areas. On hardbottom habitat, turf algae was 

significantly higher in the Guánica study area while filamentous/cyanobacteria was significantly higher in the La Parguera 

study area (Table 2.2). 

Figure 2.17. Percent cover of turf algae. 

Figure 2.18. Percent cover of crustose coralline algae (CCA). 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

19 Fish and Benthic Communities 

Seagrass cover in the Guánica study area ranged from 0-57.6% and was highest in the inshore waters on unconsolidated 

sediment sites, particularly east of Guánica Bay and north of Cayos de Caña Gorda (Figure 2.20). Turtle grass (Thalassia testudinum) was the dominant species of seagrass on unconsolidated sediment sites in the Guánica study area (5.7 

± 3.1%), followed by paddle grass (Halophila decipiens) (1.8 ± 0.7%), shoal grass (Haldoule wrightii) (1.8 ± 0.1%) and 

manatee grass (Syringodium filiforme) (0.5 ± 0.3%; Figure 2.21 and Figure 2.22). Seagrass amounts were lower in mangrove habitat, where total seagrass cover averaged 3.6 (± 2.0)% and was present primarily as turtle grass (Figure 2.7c). 

In the La Parguera study area, seagrass cover ranged from 0-71.8% and was also highest in nearshore and lagoonal 

habitats Figure 2.20). Turtle grass was the dominant species of seagrass on unconsolidated sediment sites, 

averaging 12.6 (± 2.5%; Figure 2.21), followed by H. decipens (4.8 ± 1.3%). Turtle grass was the primary species in 

shallow, near-shore waters, while H. decipens exhibited higher cover in the deeper waters seaward of the mangrove 

cayes. Both shoal grass and manatee grass were less common and generally present in small amounts (<1% cover). 

Figure 2.19. Percent cover of filamentous algae (FA) and cyanobacteria (CB). 

Figure 2.20. Percent cover of seagrass. 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Fish and Benthic Communities 

There was a significantly greater amount of 

seagrass on the unconsolidated sediment 

sites of the La Parguera study area compared to the Guánica study area (Table 2.2). 

Some of the differences may be attributed 

to the inherent geomorphological differences between the two study areas. The La 

Parguera study area contains a much larger 

protected lagoonal area, spanning almost 

the entire width of the study area. In the 

Guánica study area, protected lagoons are 

located at the western end of the study area 

(contiguous form the La Parguera study 

area) and to the east of Guánica Bay, where 

the highest seagrass cover values were observed in this study. The area in between 

these two lagoonal features is less protected and much more exposed to waves and 

currents. Immediately south and west of 

Guánica Bay, there is an expanse of sand/ 

mud that has patchy seagrass or has been 

mapped as having no appreciable cover 

Percent cover (%) 

16

14

12

10

8

6

4

2

0

Guanica 

Parguera 

Thalassia Syringodium Halophila Halodule wrightii 

testudinum filiforme decipiens 

Figure 2.21. Mean percent cover of each seagrass species in unconsolidated sediments sites in the Guánica and La Parguera study areas. 

(Bauer et al., 2012). Whether this pattern has been influenced by exposure to sediment runoff from the bay, dredging of 

the shipping channel or other anthropogenic influences is unknown. 

Figure 2.22. Seagrass species documented in Guánica and La Parguera surveys. 

Macroinvertebrates 

A total of 24 Queen conch (Eustrombus gigas) were reported between the two study areas (Figure 2.23), including 18 

individuals from the Guánica study area, three of which were mature, and six individuals from the La Parguera study area, 

two of which were mature. A total of seven lobsters (Panularis argus) were reported between the two study areas, only 

one of which was observed within the Guánica study area. This individual was observed in a survey transect close to the 

shelf edge (Figure 2.24). Of the remaining six lobsters seen in the La Parguera study area, five were observed at a single 

mangrove site. All long-spined urchins (Diadema antillarium) were observed within the La Parguera study area; no longspined urchins were observed in the Guánica study area surveys (Figure 2.25). 

Marine Debris 

A total of 94 marine debris items were found among the field surveys of the Guánica and La Parguera study areas (Table 

2.3). The absolute number of debris items within a transect area (100 m2

) ranged from 0-11. Debris was present at a total 

of 29 sample sites, five in the Guánica study area (8% of sites) and 24 in the La Parguera study area (13% of sites). Derelict fishing gear accounted for 11% of the reported debris, half of which was attributed to derelict traps or trap material. 

The majority of the debris items were non-fishing related debris (88%), including cans, bottles and tires. Other non-fishing 

related items included items such as: plastic bags, a plastic tricycle and a visor. The majority of the marine debris items 

were found along the shoreline and in the mangrove cays of La Parguera (Figure 2.26). The few debris items seen in 

Guánica were confined to the shoreline and nearshore cays. Only a select few items were found on the outer shelf of La 

Parguera, and included a relic fish pot, derelict trap material and two glass bottles (Table 2.3). 

20 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

21 Fish and Benthic Communities 

Figure 2.23. Spatial distribution of Queen conch (Eustrombus gigas). 

Figure 2.24. Spatial distribution of spiny lobster (Panularis argus). 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

22 Fish and Benthic Communities 

Figure 2.25. Spatial distribution of long spined urchin (Diadema antillarium). 

Figure 2.26. Spatial distribution of marine debris. 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Fish and Benthic Communities 

Table 2.3. Frequency of debris types pooled across all Guánica and La Parguera survey sites. 

debris type total number % of total debris 

Fishing line/reel 3 3.2 

Derelict trap/materials 6 6.4 

Net 2 2.1 

total gear pieces 11 11.7 

Cans 28 29.8 

Bottles 26 27.7 

Rope 2 2.1 

Tires 2 2.1 

Other 25 26.6 

total non-gear 83 88.3 

total debris 94 100 

fish Assemblages

The fish community observed in the 2010 Guánica study area consisted of 36 taxonomic families and 119 species, while 

the La Parguera study area was represented by 43 families and 165 species over the 2008-2010 time period. Fish species richness ranged from 1 to 38 species per site (100 m2

) and was highest on hardbottom sites, especially close to the 

shelf edge, followed by mangrove (Figure 2.27a and Figure 2.28). Unconsolidated sediments were typified by lower species richness. Shannon diversity, which is a product of richness and evenness, followed similar trends (Figure 2.27b and 

Figure 2.29); however, diversity was significantly greater on hardbottom within the La Parguera study area compared to 

hardbottom within the Guánica study area (Table 2.4). 

Mangrove sites typically exhibited the highest total fish density; however this was largely due to the presence of schooling 

round herring (Jenkensia spp.) and other small unidentified clupeiids, which can be orders of magnitude greater (100s– 

1,000s) than the next most abundant fish. Following removal of these small baitfish, mean fish density in mangrove was 

slightly lower compared with hardbottom, although typically more variable (Figure 2.27c). In the Guánica study area, the 

hardbottom survey sites situated on the southern portion of the shelf generally exhibited the highest density (Figure 2.30). 

Lowest density was typically observed on unconsolidated sediments, particularly at unvegetated sites. Similar patterns 

0 

0.5 

1 

1.5 

2 

2.5 

3 

Hardbottom Mangrove Unconsolidated 

Sediments 

Mean Shannon diversity (/100 m2 )

Guanica 

Parguera 

0 

5 

10 

15 

20 

25 

Hardbottom Mangrove Unconsolidated 

Sediments 

Mean species richness (/100 m2 ) 

Guanica 

Parguera 

0 

20 

40 

60 

80 

100 

120 

140 

Hardbottom Mangrove Unconsolidated 

Sediments 

Mean density (#/100 m2 ) 

0 

1000 

2000 

3000 

4000 

5000 

6000 

7000 

8000 

9000 

Hardbottom Mangrove Unconsolidated 

Sediments 

Mean biomass (g/100 m2 ) 

a) b) 

c) d) 

Figure 2.27. Mean (±SE) fish species a) richness, b) Shannon diversity, c) density and d) biomass by habitat type and study area. 

23 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

24 Fish and Benthic Communities 

were evident in La Parguera study area, with a concentration of high species richness sites near the outer reef edge; however some areas of moderate to high species richness were also found inshore of the reef edge on hardbottom habitats. 

Highest levels of biomass generally occurred on hardbottom, particularly offshore near the shelf edge (Figure 2.27d and 

Figure 2.31). Within the Guánica study area, three out of the five sites with the greatest biomass were located in the fareastern strata. Unconsolidated sediments were characterized by lowest mean biomass. Higher biomass was recorded at 

a few unconsolidated sediment sites, often when pelagic species such as great barracuda (Sphyraena barracuda), southern stingray (Dasyatis americana) or blue runner (Caranx cryos) passed through a transect. No significant differences 

were detected in density and biomass metrics between the two study areas (Table 2.4) for all three habitat types/strata. 

Figure 2.28. Fish species richness. 

Figure 2.29. Fish species diversity. 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Fish and Benthic Communities 

The nMDS and ANOSIM analyses further indicate that fish assemblages in southwest Puerto Rico differ by bottom type, 

but are similar between the two study areas. There was a clear separation of fish communities between hardbottom, 

unconsolidated sediment and mangrove surveys (Figure 2.32). Mangrove and hardbottom sites tended to be highly 

clustered, indicating a high degree of similarity in species composition among sites within each respective habitat type. 

In contrast, unconsolidated sediment sites tended to be more dispersed, indicating more dissimilarity among sites within 

this group. While sites within this bottom type were generally characterized by low overall abundance, they often varied in 

their species composition. Within bottom types, there was not a distinct separation of sites between the La Parguera and 

Guánica study areas. The results of the ANOSIM test also indicate that there was a statistically significant difference in 

community composition among the three bottom types (R=0.664, p<0.001), but the effect of study area was not significant 

(R=0.111, p<0.50). 

Table 2.4. Results of nonparametric analysis (Wilcoxon-Mann Whitney) for fish community metrics between the Guánica and La Parguera study areas. As described in the methods, a random subset of the La Parguera (2008-2010) dataset was used. Bold text with an 

asterisk (*) indicates a significant difference at the α=0.05 level. 

metric hardbottom mangrove unconsolidated 

sediments 

Z p-value Z p-value Z p-value 

Total density 1.14 0.255 0.88 0.377 -0.90 0.366 

Total biomass 1.06 0.290 0.62 0.536 0.27 0.787 

Species richness -1.08 0.279 1.25 0.210 -1.34 0.180 

Shannon diversity -2.11 0.035* 0.00 1.000 -1.04 0.296 

Herbivore density 0.33 0.739 0.40 0.689 -2.31 0.021* 

Invertivore density 2.27 0.023* -0.31 0.757 -0.68 0.495 

Piscivore density 1.11 0.269 1.46 0.143 -0.82 0.413 

Planktivore density -1.96 0.050* 1.18 0.237 -0.36 0.716 

Herbivore biomass -0.42 0.673 -0.97 0.331 -1.21 0.225 

Invertivore biomass 1.81 0.070 -1.15 0.251 0.11 0.916 

Piscivore biomass 1.77 0.077 0.88 0.377 -0.86 0.391 

Planktivore biomass -1.44 0.150 0.91 0.363 -0.35 0.726 

Grouper (Serranidae) density 1.00 0.317 0.89 0.374 -1.40 0.162 

Grouper (Serranidae) biomass 0.82 0.410 0.89 0.374 -1.40 0.162 

Cephalopholis fulva density 2.43 0.015* 0.00 1.000 0.00 1.000 

Cephalopholis fulva biomass 2.27 0.023* 0.00 1.000 0.00 1.000 

Cephalopholis cruentata density 0.12 0.907 0.89 0.374 -1.40 0.162 

Cephalopholis cruentata biomass 0.37 0.711 0.89 0.374 -1.40 0.162 

Snappers (Lutjanidae) density -1.35 0.177 -1.02 0.308 0.54 0.590 

Snappers (Lutjanidae) biomass -0.46 0.644 0.09 0.930 0.00 1.000 

Lutjanus apodus density 0.42 0.671 0.36 0.722 0.00 1.000 

Lutjanus apodus biomass 0.33 0.740 1.06 0.289 0.00 1.000 

Lutjanus synagris density 0.57 0.570 0.89 0.374 1.89 0.059 

Lutjanus synagris biomass 0.61 0.544 0.89 0.374 1.68 0.094 

Lutjanus griseus density 0.00 1.000 -1.44 0.151 0.00 1.000 

Lutjanus griseus biomass 0.00 1.000 -0.18 0.859 0.00 1.000 

Ocyurus chrysurus density -1.99 0.046* -1.77 0.077 -1.00 0.315 

Ocyurus chrysurus biomass -1.18 0.239 -1.77 0.077 -0.97 0.331 

Grunts (Haemulidae) density 0.42 0.673 -0.88 0.377 -0.50 0.619 

Grunts (Haemulidae) biomass 0.78 0.436 -2.03 0.042* -0.58 0.560 

Haemulon flavolineatum desnity 0.88 0.378 0.98 0.328 0.00 1.000 

Haemulon flavolineatum biomass 0.72 0.470 0.00 1.000 0.00 1.000 

Haemulon sciurus density 1.31 0.189 0.00 1.000 0.00 1.000 

Haemulon sciurus biomass 1.26 0.208 -1.95 0.052 0.00 1.000 

Haemulon plumierii density 0.59 0.557 0.61 0.540 -1.40 0.162 

25 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Fish and Benthic Communities 

Table 2.4 (continued). Results of nonparametric analysis (Wilcoxon-Mann Whitney) for fish community metrics between the Guánica 

and La Parguera study areas. As described in the methods, a random subset of the La Parguera (2008-2010) dataset was used. Bold 

text with an asterisk (*) indicates a significant difference at the α=0.05 level. 

metric hardbottom mangrove unconsolidated 

sediments 

Z p-value Z p-value Z p-value 

Haemulon plumierii biomass 0.62 0.537 0.61 0.540 -1.40 0.162 

Haemulon aurolineatum density 0.48 0.633 -0.89 0.374 -0.95 0.340 

Haemulon aurolineatum biomass 0.45 0.655 -0.89 0.374 -0.95 0.340 

Surgeonfish (Acanthuridae) density 1.05 0.295 1.10 0.273 -0.02 0.981 

Surgeonfish (Acanthuridae) biomass -0.53 0.594 1.21 0.225 0.02 0.981 

Acanthurus bahianus density 0.39 0.699 -0.89 0.374 0.56 0.572 

Acanthurus bahianus biomass -1.40 0.162 -0.89 0.374 0.62 0.537 

Acanthurus coeruleus density 1.04 0.300 1.37 0.169 -0.95 0.340 

Acanthurus coeruleus biomass 1.22 0.223 1.37 0.169 -0.95 0.340 

Parrotfish (Scaridae) density -4.20 <0.001* 1.32 0.187 -1.74 0.081 

Parrotfish (Scaridae) biomass -2.22 0.027* 0.64 0.524 -1.28 0.200 

Scarus iseri density -3.15 0.002* 1.61 0.108 -0.99 0.323 

Scarus iseri biomass -3.12 0.002* 1.71 0.088 -0.94 0.347 

Sparisoma aurofrenatum density -2.59 0.010* 0.00 1.000 0.00 1.000 

Sparisoma aurofrenatum biomass -2.14 0.033* 0.00 1.000 -0.07 0.944 

Sparisoma viride density -1.21 0.225 0.61 0.540 0.00 1.000 

Sparisoma viride biomass -0.92 0.360 0.54 0.587 0.00 1.000 

Wrasses (Labridae) density 2.80 0.005* 1.77 0.077 1.30 0.195 

Wrasses (Labridae) biomass 2.74 0.006* 1.77 0.077 2.05 0.040* 

Goatfish (Mullidae) density -1.61 0.107 0.00 1.000 -2.05 0.041* 

Goatfish (Mullidae) biomass -1.43 0.154 0.00 1.000 -2.05 0.041* 

Damselfish (Pomacentridae) density 3.15 0.002* 0.62 0.534 -0.92 0.355 

Damselfish (Pomacentridae) biomass 0.33 0.739 0.53 0.596 -0.92 0.355 

26 

Figure 2.30. Total fish density. 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

27 Fish and Benthic Communities 

Figure 2.31. Total fish biomass. 

Figure 2.32. Non-metric multidimensional (nMDS) scaling ordination based on between site similarity composition 

using fish abundance data. Sites are color-coded by habitat type and study area. 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Fish and Benthic Communities 

Trophic Groups, Families and Species 

Biomass and abundance were distributed unevenly throughout trophic groups (Figures 2.33-2.36). On hardbottom and 

unconsolidated sediments, biomass and density were greatest for herbivores and invertivores (see Appendix A, Tables 

A.1 and A.2) for species list by trophic guild; Figure 2.33 and Figure 2.34). Mean herbivore abundance and particularly 

biomass were markedly higher on hardbottom than the other bottom types (Figure 2.33). In particular, the highest values 

of herbivore biomass were observed on hardbottom along the outer shelf. Herbivore density on unconsolidated sediments 

varied significantly between the two study areas (Table 2.4) with higher values in the La Parguera study area. Mean herbivore density in mangrove habitat was over three times greater in the La Parguera study area compared to the Guánica 

study area, but there was no significant difference between the study areas due to high variability between sites (Table 2.4). 

a) 

0 

20 

40 

60 

80 

100 

120 

140 

160 

Mean density (#/100 m2 ) 

Hardbottom Mangrove Unconsolidated 

Sediments 

Guanica 

Parguera 

b) 

0 

500 

1000 

1500 

2000 

2500 

3000 

3500 

Mean biomass (#/100 m2 ) 

Hardbottom Mangrove Unconsolidated 

Sediments 

Guanica 

Parguera 

c) 

Figure 2.33. a) Spatial distribution, b) mean (±SE) density by habitat and c) mean (±SE) biomass by habitat of herbivores. 

28 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Fish and Benthic Communities 

Invertivores (I; see Appendix A, Tables A.1, A.2 for complete list) were distributed throughout the study area, with the 

highest levels observed on hardbottom and in mangrove habitat (Figure 2.34). Results of the non-parametric Wilcoxon 

tests indicate that density of invertivores were significantly greater in hardbottom surveys within the Guánica study area 

compared to the La Parguera study area (Table 2.4). This was partly attributed to several sites on the outer shelf in the 

Guánica study area that were characterized by high densities of a number of invertivore species. 

a) 

0 

10 

20 

30 

40 

50 

60 

70 

80 

90 

100 

Mean density (#/100 m2 ) 

Hardbottom Mangrove Unconsolidated 

Sediments 

Guanica 

Parguera 

b) 

0 

500 

1000 

1500 

2000 

2500 

3000 

3500 

Mean biomass (#/100 m2 ) 

Hardbottom Mangrove Unconsolidated 

Sediments 

Guanica 

Parguera 

c) 

Figure 2.34. a) Spatial distribution, b) mean (±SE) density by habitat and c) mean (±SE) biomass by habitat of invertivores. 

29 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Fish and Benthic Communities 

Piscivores (P; see Appendix A, Tables A.1, A.2 for complete list) constituted a small percentage of total fish abundance, 

but made up a greater proportion of the biomass (Figure 2.35). Piscivores were most abundant in mangroves, but individuals were generally juveniles. A few unconsolidated sediment sites exhibited high biomass due to the presence of species such as Great barracuda and Carangidae (jack) species. In mangrove habitats, planktivores exhibited highest mean 

density and variability due to occasional large schools of small clupeids (Figure 2.36). 

a) 

0 

5 

10 

15 

20 

25 

Mean density (#/100 m2 ) 

Hardbottom Mangrove Unconsolidated Sediments 

Guanica 

Parguera 

b) 

0 

500 

1000 

1500 

2000 

2500 

3000 

Mean biomass (#/100 m2 ) 

Hardbottom Mangrove Unconsolidated 

Sediments 

Guanica 

Parguera c) 

Figure 2.35. a) Spatial distribution, b) mean (±SE) density by habitat and c) mean (±SE) biomass by habitat of piscivores. 

For each bottom type and study area, rankings of families with the highest mean abundance and biomass are presented 

in Figures 2.37 and 2.38. Wrasse (Labridae), damselfish (Pomacentridae) and parrotfish (Scaridae) families were most 

numerically abundant on hardbottom habitats in both the Guánica and La Parguera study areas; although their rankings 

differed between study areas (Figure 2.37a-b). Top-ranked families differed for biomass between study areas. Parrotfish 

ranked highest in terms of biomass in the La Parguera study area, followed by surgeonfishes (Acanthuridae; Figure 

2.38b). The three families that accounted for the highest proportional biomass in the Guánica study area were triggerfishes (Balistidae), jacks (Carangidae) and grunts (Haemulidae; Figure 2.38a). All three families exhibited high between 

site variability. 

Within mangrove habitats of both study areas, small schooling fishes in the Clupeidae family were patchily abundant 

and accounted for the highest mean density, particularly in the Guánica study area (Figure 2.37c-d). Snappers (Family 

Lutjanidae) accounted for the highest mean biomass in both study areas, followed by grunts (Family Haemulidae; Figure 2.38c-d). In addition, barracudas (Family Sphyraenidae) were commonly observed in mangrove and mean biomass 

ranked fourth and third among family groups in the Guánica and La Parguera study areas, respectively. 

30 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Fish and Benthic Communities 

a) 

2000 

2500 

2 ) 0 m

Guanica 

Parguera b) 

300 

350 

400 

0 m

Guanica 

Parguera c) 

0 

500 

1000 

1500 

Mean density (#/10

Hardbottom Mangrove Unconsolidated 

Sediments 

0 

50 

100 

150 

200 

250 

Mean biomass (#/10 2 ) 

Hardbottom Mangrove Unconsolidated 

Sediments 

Figure 2.36. a) Spatial distribution, b) mean (±SE) density by habitat and c) mean (±SE) biomass by habitat of planktivores. 

Mean density and biomass of family groups were typically variable on unconsolidated sediments. Grunts accounted for 

the highest mean density in the Guánica study area, while silversides (Atherinidae) dominated in the La Parguera study 

area with a high standardd error (Figure 2.37e-f). Larger-bodied families Sphyraenidae, Dasyatidae (stingrays) and Carangidae, though infrequently observed, accounted for the highest mean biomass in the Guánica study area, while stingrays were not observed on surveys within the La Parguera study area (Figure 2.38e-f). 

31 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Fish and Benthic Communities 

0 

5 

10 

15 

20 

25 

30 

35 

40 

45 

50 

Mean density (#/100 m2 ) 

a) hardbottom (guanica) 

Guanica 

0 

500 

1000 

1500 

2000 

2500 

3000 

Mean density (#/100 m2 ) 

c) mangrove (guanica) 

Guanica 

0 

2 

4 

6 

8 

10 

12 

Mean density (#/100 m2 ) 

e) unconsolidated sediments (guanica) 

Guanica 

0 

5 

10 

15 

20 

25 

30 

Mean density (#/100 m2 ) 

b) hardbottom (la Parguera) 

Parguera 

0 

50 

100 

150 

200 

250 

300 

350 

400 

450 

500 

Mean density (#/100 m2 ) 

d) mangrove (la Parguera) 

Parguera 

0 

5 

10 

15 

20 

25 

30 

35 

40 

Mean density (#/100 m2 ) 

f) unconsolidated sediments (la Parguera) 

Parguera 

Figure 2.37. Mean (±SE) density of the major (top ten) fish families by habitat and study area. 

32 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Fish and Benthic Communities 

0 

500 

1000 

1500 

2000 

2500 

Mean biomass (g/100 m2 ) 

a) hardbottom (guanica) 

Guanica 

0 

200 

400 

600 

800 

1000 

1200 

1400 

1600 

Mean biomass (g/100 m2) 

c) mangrove (guanica) 

Guanica 

0 

200 

400 

600 

800 

1000 

1200 

1400 

1600 

Mean biomass (g/100 m2 ) 

e) unconsolidated sediments (guanica) 

Guanica 

0 

200 

400 

600 

800 

1000 

1200 

Mean biomass (g/100 m2 ) 

b) hardbottom (la Parguera) 

Parguera 

0 

200 

400 

600 

800 

1000 

1200 

1400 

Mean biomass (g/100 m2 ) 

d) mangrove (la Parguera) 

Parguera 

0 

200 

400 

600 

800 

1000 

1200 

Mean biomass (g/100 m2 ) 

f) unconsolidated sediments (la Parguera) 

Parguera 

Figure 2.38. Mean (±SE) biomass of the major (top ten) fish families by habitat and study area. 

33 
0

2

4

6

8

10

12

Hardbottom Mangrove Unconsolidated

Sediments

Mean density (#/100 m2)

Guanica

Parguera

0

100

200

300

400

500

600

700

Hardbottom Mangrove Unconsolidated

Sediments

Mean biomass (#/100 m2)

Guanica

Parguera

0

10

20

30

40

50

60

70

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35

Frequency (%)

0

2

4

6

8

10

12

Hardbottom Mangrove Unconsolidated

Sediments

Mean density (#/100 m2)

Guanica

Parguera

0

100

200

300

400

500

600

700

Hardbottom Mangrove Unconsolidated

Sediments

Mean biomass (#/100 m2)

0

10

20

30

40

50

60

70

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35

Frequency (%)

Guanica

Parguera

Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Fish and Benthic Communities 

Groupers (Serranidae) 

Groupers (Cephalopholis and Epinephelus spp.) were infrequent, primarily small in size and were almost exclusively 

found on hardbottom (Figure 2.39). In both study areas, most grouper individuals belonged to three species: coney (C. 

fulva), graysby (C. cruentata) and red hind (E. guttatus). In addition, one Nassau grouper (E. striatus) was documented 

in the La Parguera study area, while three rock hind (E. adscensionis) were observed in the Guánica study area. Across 

the region, the vast majority of individuals were observed on hardbottom, particularly near the shelf edge (Figure 2.39). 

While more grouper were observed in Guánica than La Parguera, grouper density and biomass were not significantly different between the two study areas (Table 2.4). Species of the genus Myctoperca were conspicuously absent from both 

study areas. 

a) 

0 

0.2 

0.4 

0.6 

0.8 

1 

1.2 

1.4 

1.6 

1.8 

Mean density (#/100 m2 ) 0 

5 

10 

15 

20 

25 

30 

35 

40 

45 

50 

Frequency (%) 

Hardbottom 

0-5 5-10 10-15 

Mangrove 

15-20 20-25 

Unconsolidated 

Sediments 

Guanica 

Parguera 

25-30 30-35 >35 

Guanica 

Parguera 

b) 

d) 

0 

20 

40 

60 

80 

100 

120 

140 

Mean biomass (#/100 m2 ) 

Hardbottom Mangrove Unconsolidated 

Sediments 

Guanica 

Parguera 

c) 

34 

Figure 2.39. a) Spatial distribution, b) mean (±SE) density by habitat, c) mean (±SE) biomass by habitat and d) size (cm) frequency of 

groupers (Family Serranidae). 
0

2

4

6

8

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12

Hardbottom Mangrove Unconsolidated

Sediments

Mean density (#/100 m2)

0

100

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700

Hardbottom Mangrove Unconsolidated

Sediments

Mean biomass (#/100 m2)

Guanica

Parguera

0

10

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30

40

50

60

70

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35

Frequency (%)

Guanica

Parguera

0

2

4

6

8

10

12

Hardbottom Mangrove Unconsolidated

Sediments

Mean density (#/100 m2)

Guanica

Parguera

0

100

200

300

400

500

600

700

Hardbottom Mangrove Unconsolidated

Sediments

Mean biomass (#/100 m2)

Guanica

Parguera

0

10

20

30

40

50

60

70

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35

Frequency (%)

0

2

4

6

8

10

12

Hardbottom Mangrove Unconsolidated

Sediments

Mean density (#/100 m2)

Guanica

Parguera

0

100

200

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400

500

600

700

Hardbottom Mangrove Unconsolidated

Sediments

Mean biomass (#/100 m2)

0

10

20

30

40

50

60

70

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35

Frequency (%)

Guanica

Parguera

0

2

4

6

8

10

12

Hardbottom Mangrove Unconsolidated

Sediments

Mean density (#/100 m2)

0

100

200

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Hardbottom Mangrove Unconsolidated

Sediments

Mean biomass (#/100 m2)

Guanica

Parguera

0

10

20

30

40

50

60

70

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35

Frequency (%)

Guanica

Parguera

Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Fish and Benthic Communities 

Coney was the most abundant grouper species observed in the study and was found exclusively on hardbottom. This 

species exhibited a strong spatial pattern; the majority of individuals were located offshore close to the shelf edge (Figure 

2.40). The majority of individuals were small adults. The species was sighted more frequently in the Guánica study area 

and results of a non-parametric Wilcoxon-Mann Whitney test indicate abundance and biomass were significantly greater 

in the Guánica study area (Table 2.4). This may be at least partly due to the species preference for shelf edge environments which was under-sampled in the La Parguera study area because the 2001 map did not extend to the shelf edge. 

a) 

0 

0.2 

0.4 

0.6 

0.8 

1 

1.2 

Mean density (#/100 m2) 

0 

10 

20 

30 

40 

50 

60 

Frequency (%) 

Hardbottom 

0-5 5-10 10-15 

Juveniles/subadults 

Mangrove 

15-20 20-25 

Guanica 

Parguera 

Unconsolidated 

Sediments 

25-30 30-35 >35 

Guanica 

Parguera 

b) 

d) 

Guanica 

Parguera 

0 

10 

20 

30 

40 

50 

60 

70 

80 

90 

100 

Mean biomass (#/100 m2) 

Hardbottom Mangrove Unconsolidated 

Sediments 

Guanica 

Parguera 

c) 

Figure 2.40. a) Spatial distribution, b) mean (±SE) density by habitat c) mean (±SE) biomass by habitat and d) size (cm) frequency of 

coney (Cephalopholis fulva). 

35 
0

2

4

6

8

10

12

Hardbottom Mangrove Unconsolidated

Sediments

Mean density (#/100 m2)

Guanica

Parguera

0

100

200

300

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500

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700

Hardbottom Mangrove Unconsolidated

Sediments

Mean biomass (#/100 m2)

Guanica

Parguera

0

10

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50

60

70

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35

Frequency (%)

0

2

4

6

8

10

12

Hardbottom Mangrove Unconsolidated

Sediments

Mean density (#/100 m2)

0

100

200

300

400

500

600

700

Hardbottom Mangrove Unconsolidated

Sediments

Mean biomass (#/100 m2)

Guanica

Parguera

0

10

20

30

40

50

60

70

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35

Frequency (%)

Guanica

Parguera

0

2

4

6

8

10

12

Hardbottom Mangrove Unconsolidated

Sediments

Mean density (#/100 m2)

Guanica

Parguera

0

100

200

300

400

500

600

700

Hardbottom Mangrove Unconsolidated

Sediments

Mean biomass (#/100 m2)

0

10

20

30

40

50

60

70

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35

Frequency (%)

Guanica

Parguera

0

2

4

6

8

10

12

Hardbottom Mangrove Unconsolidated

Sediments

Mean density (#/100 m2)

Guanica

Parguera

0

100

200

300

400

500

600

700

Hardbottom Mangrove Unconsolidated

Sediments

Mean biomass (#/100 m2)

Guanica

Parguera

0

10

20

30

40

50

60

70

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35

Frequency (%)

Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Fish and Benthic Communities 

Graysby exhibited a similar spatial pattern to coney except that the species was occasionally observed in nearshore 

mangrove and unconsolidated sediment habitats in addition to hardbottom farther out on the shelf. Biomass and density 

did not differ significantly between study areas in the three surveyed habitats (Figure 2.41b-c and Table 2.4). The species 

was absent from survey sites in the eastern portion of the Guánica study area (Figure 2.41). The majority of individuals 

were subadults and small adults (Figure 2.41d). Red hind was infrequently observed, sighted in 4% and 5% of survey 

transects in the La Parguera and Guánica study areas, respectively. The species was found exclusively on hardbottom. 

a) 

0 

0.05 

0.1 

0.15 

0.2 

0.25 

0.3 

0.35 

0.4 

0.45 

Mean density (#/100 m2 ) 0 

10 

20 

30 

40 

50 

60 

Frequency (%) 

Hardbottom 

0-5 5-10 10-15 

Juveniles/subadults 

Mangrove 

15-20 20-25 

Guanica 

Parguer d) 

Unconsolidated 

Sediments 

25-30 30-35 >35 

Guanica 

Parguera b) 

Guanicaa 

Parguera d) 

0 

5 

10 

15 

20 

25 

30 

Mean biomass (#/100 m2 ) 

Hardbottom Mangrove Unconsolidated 

Sediments 

Guanica 

Parguera 

c) 

36 

Figure 2.41. a) Spatial distribution, b) mean (±SE) density by habitat, c) mean (±SE) biomass by habitat and d) size (cm) frequency of

graysby (Cephalopholis cruentata). 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Fish and Benthic Communities 

Snappers (Lutjanidae) 

Snappers were detected across the shelf in all investigated habitats but were most abundant in mangroves (Figure 

2.42a-b). However, as described below, distribution varied by species and lifestage. The lowest biomass was observed 

over unconsolidated sediments (Figure 2.42c). Within the two study areas, eight Lutjanid species were documented, with 

schoolmaster (Lutjanus apodus), yellowtail (Ocyurus chrysurus), lane (L. synagris) and gray snappers (L. griseus) accounting for the majority of observations (98%). The remaining species were infrequently sighted (Appendix A, Tables A.1, 

A.2). Lutjanidae size frequency was skewed toward smaller size classes (<15 cm; Figure 2.42d). 

a) 

0 

5 

10 

15 

20 

25 

Mean density (#/100 m2 ) 

0 

5 

10 

15 

20 

25 

30 

35 

Frequency (%) 

Hardbottom Mangrove 

0-5 5-10 10-15 15-20 20-25 

Unconsolidated 

Sediments 

Guanica 

Parguera 

25-30 30-35 >35 

Guanica 

Parguera 

b) 

d) 

0 

200 

400 

600 

800 

1000 

1200 

1400 

1600 

Mean biomass (#/100 m2 ) 

Hardbottom Mangrove Unconsolidated 

Sediments 

Guanica 

Parguera c) 

Figure 2.42. a) Spatial distribution, b) mean (±SE) density by habitat, c) mean (±SE) biomass by habitat and d) size (cm) frequency of 

snappers (Family Lutjanidae). 

37 
0

2

4

6

8

10

12

Hardbottom Mangrove Unconsolidated

Sediments

Mean density (#/100 m2)

0

100

200

300

400

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600

700

Hardbottom Mangrove Unconsolidated

Sediments

Mean biomass (#/100 m2)

Guanica

Parguera

0

10

20

30

40

50

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70

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35

Frequency (%)

Guanica

Parguera

0

2

4

6

8

10

12

Hardbottom Mangrove Unconsolidated

Sediments

Mean density (#/100 m2)

Guanica

Parguera

0

100

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500

600

700

Hardbottom Mangrove Unconsolidated

Sediments

Mean biomass (#/100 m2)

Guanica

Parguera

0

10

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30

40

50

60

70

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35

Frequency (%)

0

2

4

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12

Hardbottom Mangrove Unconsolidated

Sediments

Mean density (#/100 m2)

Guanica

Parguera

0

100

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700

Hardbottom Mangrove Unconsolidated

Sediments

Mean biomass (#/100 m2)

0

10

20

30

40

50

60

70

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35

Frequency (%)

Guanica

Parguera

Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Fish and Benthic Communities 

Schoolmaster were observed at 21% and 19% of survey transects within the Guánica and La Parguera study areas, respectively. They were most abundant in nearshore mangrove fringes and cays (Figure 2.43a-b). A few individuals were 

observed on offshore hardbottom habitat, while none were observed on unconsolidated sediments. In both study areas, 

the majority of schoolmaster (>90%) were juveniles/subadults (Figure 2.43d). With the exception of one hardbottom site, 

all adult-sized individuals, about 7% of the total, were located on mangrove habitat. 

0 

2 

4 

6 

8 

10 

12 

14 

16 

18 

Hardbottom Mangrove Unconsolidated 

Sediments 

Mean density (#/100 m2 ) 

Guanica 

Parguera 

0 

100 

200 

300 

400 

500 

600 

700 

800 

900 

Hardbottom Mangrove Unconsolidated 

Sediments 

Mean biomass (#/100 m2 ) 

0 

5 

10 

15 

20 

25 

30 

35 

40 

45 

50 

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35 

Frequency (%) 

Juveniles/subadults 

Guanica 

Parguera 

Guanica 

Parguera 

Guanica 

Parguera 

a)

b) c)

d)

38 

Figure 2.43. a) Spatial distribution, b) mean (±SE) density by habitat, c) mean (±SE) biomass by habitat and d) size (cm) frequency of 

schoolmaster (Lutjanus apodus). 
0

2

4

6

8

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12

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Sediments

Mean density (#/100 m2)

0

100

200

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700

Hardbottom Mangrove Unconsolidated

Sediments

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Guanica

Parguera

0

10

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30

40

50

60

70

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35

Frequency (%)

Guanica

Parguera

0

2

4

6

8

10

12

Hardbottom Mangrove Unconsolidated

Sediments

Mean density (#/100 m2)

Guanica

Parguera

0

100

200

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400

500

600

700

Hardbottom Mangrove Unconsolidated

Sediments

Mean biomass (#/100 m2)

Guanica

Parguera

0

10

20

30

40

50

60

70

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35

Frequency (%) 0

2

4

6

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10

12

Hardbottom Mangrove Unconsolidated

Sediments

Mean density (#/100 m2)

Guanica

Parguera

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Sediments

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0

10

20

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40

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0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35

Frequency (%)

Guanica

Parguera

Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Fish and Benthic Communities 

Lane snapper were observed in 26% of survey transects in the Guánica study area and 9% of sites within the La Parguera study area. The majority of sightings occurred on unconsolidated sediment habitat (Figure 2.44a,b). The species 

was generally observed in small numbers, but on one survey transect in the Guánica studya area, 29 individuals were 

observed. There were no significant differences in density or biomass between the two study areas (Table 2.4). In both 

study areas, the vast majority of individuals were juveniles in the two smallest size classes (0-5 and 5-10 cm). Only one 

adult was recorded in Guánica and no adults in La Parguera (Figure 2.44d). 

a)

0 

0.5 

1 

1.5 

2 

2.5 

3 

3.5 

4 

4.5 

5 

Mean density (#/100 m2 ) 

0 

10 

20 

30 

40 

50 

60 

70 

80 

90 

Frequency (%) 

Hardbottom Mangrove 

0-5 5-10 10-15 15-20 20-25 

Juveniles/subadults 

Unconsolidated 

Sediments 

G nica 

Par era 

25-30 30-35 >35 

Guauanica 

Parguguera 

Guanica 

Parguera 

b)

d)

0 

5 

10 

15 

20 

25 

30 

Mean biomass (#/100 m2 ) 

Hardbottom Mangrove Unconsolidated 

Sediments 

Guanica 

Parguera c)

Figure 2.44. a) Spatial distribution, b) mean (±SE) density by habitat, c) mean (±SE) biomass by habitat and d) size (cm) frequency of

lane snapper (Lutjanus synagris). 

39 
0

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Sediments

Mean density (#/100 m2)

0

100

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Hardbottom Mangrove Unconsolidated

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Guanica

Parguera

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Guanica

Parguera

0

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Sediments

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Guanica

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Hardbottom Mangrove Unconsolidated

Sediments

Mean biomass (#/100 m2)

0

10

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70

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35

Frequency (%)

Guanica

Parguera

Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Fish and Benthic Communities 

Gray snapper was observed with similar frequency in both study areas (Guánica: 11% of surveys, La Parguera: 10% of 

surveys) and were exclusively associated with mangrove fringes and cays in both study area (Figure 2.45a,b). The three 

sites with the highest biomass were located in the fringing mangroves in the western portion of the La Parguera study 

area, similar to what was observed by Pittman et al. (2010). Observed individuals were comprised primarily of juveniles/ 

sub-adults, but several adults were observed in both study areas (Figure 2.45d). 

a) 

0 

1 

2 

3 

4 

5 

6 

Mean density (#/100 m2 ) 

0 

10 

20 

30 

40 

50 

60 

Frequency (%) 

Hardbottom Mangrove 

0-5 5-10 10-15 15-20 20-25 

Juveniles/subadults 

Unconsolidated 

Sediments 

Guanica 

Parguera 

25-30 30-35 >35 

Guanica 

Parguera 

Guanica 

Parguera 

b) 

d) 

0 

100 

200 

300 

400 

500 

600 

700 

800 

Mean biomass (#/100 m2 ) 

Hardbottom Mangrove Unconsolidated 

Sediments 

Guanica 

Parguera 

c) 

40 

Figure 2.45. a) Spatial distribution, b) mean (±SE) density by habitat, c) mean (±SE) biomass by habitat and d) size (cm) frequency of 

gray snapper (Lutjanus griseus). 
0

2

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Sediments

Mean density (#/100 m2)

0

100

200

300

400

500

600

700

Hardbottom Mangrove Unconsolidated

Sediments

Mean biomass (#/100 m2)

Guanica

Parguera

0

10

20

30

40

50

60

70

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35

Frequency (%)

Guanica

Parguera

0

2

4

6

8

10

12

Hardbottom Mangrove Unconsolidated

Sediments

Mean density (#/100 m2)

Guanica

Parguera

0

100

200

300

400

500

600

700

Hardbottom Mangrove Unconsolidated

Sediments

Mean biomass (#/100 m2)

Guanica

Parguera

0

10

20

30

40

50

60

70

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35

Frequency (%)

0

2

4

6

8

10

12

Hardbottom Mangrove Unconsolidated

Sediments

Mean density (#/100 m2)

Guanica

Parguera

0

100

200

300

400

500

600

700

Hardbottom Mangrove Unconsolidated

Sediments

Mean biomass (#/100 m2)

0

10

20

30

40

50

60

70

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35

Frequency (%)

Guanica

Parguera

Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Fish and Benthic Communities 

Mean density of yellowtail snapper was highest on hardbottom, followed by unconsolidated sediments. Mean biomass 

was also highest on hardbottom. The species was absent from mangroves in Guánica (Figure 2.46a,b). The sites with the 

highest abundance and biomass were located in the La Parguera study area. Mean density was higher in the La Parguera 

study area for all three habitats. Results in the nonparametric test indicated a significant difference in density between the 

two study areas on hardbottom habitat, but not the other two habitats (Table 2.4). This may be due to the high variability 

exhibited in both study areas. The majority of individuals were juveniles/subadults, particularly those associated with unconsolidated sediments (Figure 2.46d). Thirteen percent of yellowtail snapper present on hardbottom were small-sized 

adults between 20 and 30 cm. 

0 

0.2 

0.4 

0.6 

0.8 

1 

1.2 

1.4 

1.6 

1.8 

2 

Hardbottom Mangrove Unconsolidated 

Sediments 

Mean density (#/100 m2) 

Guanica 

Parguera 

0 

20 

40 

60 

80 

100 

120 

140 

160 

180 

200 

Hardbottom Mangrove Unconsolidated 

Sediments 

Mean biomass (#/100 m2 ) 

0 

5 

10 

15 

20 

25 

30 

35 

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35 

Frequency (%) 

Juveniles/subadults 

Guanica 

Parguera 

Guanica 

Parguera 

Guanica 

Parguera 

c) 

a) 

b) 

d) 

Figure 2.46. a) Spatial distribution, b) mean (±SE) density by habitat, c) mean (±SE) biomass by habitat and d) size (cm) frequency of

yellowtail snapper (Ocyurus chrysurus). 

41 
0

2

4

6

8

10

12

Hardbottom Mangrove Unconsolidated

Sediments

Mean density (#/100 m2)

0

100

200

300

400

500

600

700

Hardbottom Mangrove Unconsolidated

Sediments

Mean biomass (#/100 m2)

Guanica

Parguera

0

10

20

30

40

50

60

70

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35

Frequency (%)

Guanica

Parguera

0

2

4

6

8

10

12

Hardbottom Mangrove Unconsolidated

Sediments

Mean density (#/100 m2)

Guanica

Parguera

0

100

200

300

400

500

600

700

Hardbottom Mangrove Unconsolidated

Sediments

Mean biomass (#/100 m2)

Guanica

Parguera

0

10

20

30

40

50

60

70

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35

Frequency (%) 0

2

4

6

8

10

12

Hardbottom Mangrove Unconsolidated

Sediments

Mean density (#/100 m2)

Guanica

Parguera

0

100

200

300

400

500

600

700

Hardbottom Mangrove Unconsolidated

Sediments

Mean biomass (#/100 m2)

0

10

20

30

40

50

60

70

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35

Frequency (%)

Guanica

Parguera

Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Fish and Benthic Communities 

Grunts (Haemulidae) 

Fishes in the grunt family were present in all habitat types. Mangrove habitat had the highest mean density in both study 

areas, while hardbottom and unconsolidated sediment habitats exhibited similar density levels (Figure 2.47b and Table 

2.4). In the Guánica study area, biomass was highly variable on hardbottom habitat due to higher than average concentrations of grunt biomass at four survey sites near the shelf edge. The family was represented by 10 species (Appendix 

A,Tables A.1, A.2). French grunt (Haemulon flavolineatum), bluestriped grunt (H. sciurus), white grunt (H. plumierri) and 

tomtates (H. aurolineatum) were most frequently sighted and had the highest mean abundance and biomass of the 

Haemulid species. Porkfish (Anisotremus virginicus) and the remaining Haemulid species were observed less frequently 

(Appendix A, Tables A.1, A.2). Approximately one-third of observed grunts in the Guánica study area were small juveniles 

that could not be identified to the species level, compared to 56% of those in the La Parguera study area. These juveniles 

were present across all nearshore habitats but were particularly associated with mangroves and unconsolidated sediments (e.g., seagrass beds). 

a) 

0 

10 

20 

30 

40 

50 

60 

70 

80 

Mean density (#/100 m2 ) 

0 

10 

20 

30 

40 

50 

60 

Frequency (%) 

Hardbottom 

0-5 5-10 10-15 

Mangrove 

15-20 20-25 

Unconsolidated 

Sediments 

25-30 30-35 >35 

Guanica 

Parguera 

Guanica 

Parguera 

Guanica 

Parguera 

b) 

d) 

0 

200 

400 

600 

800 

1000 

1200 

1400 

Mean biomass (#/100 m2) 

Hardbottom Mangrove Unconsolidated 

Sediments 

Guanica 

Parguera 

Guanica 

Parguera c) 

42 

Figure 2.47. a) Spatial distribution, b) mean (±SE) density by habitat, c) mean (±SE) biomass by habitat and d) size (cm) frequency of 

grunts (Family Haemulidae). 
0

2

4

6

8

10

12

Hardbottom Mangrove Unconsolidated

Sediments

Mean density (#/100 m2)

0

100

200

300

400

500

600

700

Hardbottom Mangrove Unconsolidated

Sediments

Mean biomass (#/100 m2)

Guanica

Parguera

0

10

20

30

40

50

60

70

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35

Frequency (%)

Guanica

Parguera

0

2

4

6

8

10

12

Hardbottom Mangrove Unconsolidated

Sediments

Mean density (#/100 m2)

Guanica

Parguera

0

100

200

300

400

500

600

700

Hardbottom Mangrove Unconsolidated

Sediments

Mean biomass (#/100 m2)

Guanica

Parguera

0

10

20

30

40

50

60

70

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35

Frequency (%)

Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Fish and Benthic Communities 

French grunt was present in 39% and 29% of sites within the Guánica and La Parguera study areas, respectively. The 

species was most commonly observed on hardbottom and mangrove habitats and were nearly absent in unconsolidated 

sediments across the study area (Figure 2.48). While mean density was highest in mangroves, they were highly variability 

and the majority of individuals were small juveniles, particularly within the Guánica study area. In contrast, a larger range 

of sizes were present on hardbottom habitat, although sub-adults and small adults were most common. The site with the 

highest abundance (355 juveniles) was located in mangrove habitat within the La Parguera study area, while the site with 

the highest biomass was located on hardbottom near the shelf edge in the Guánica study area. 

a) 

0 

5 

10 

15 

20 

25 

30 

35 

40 

Mean density (#/100 m2 ) 0 

10 

20 

30 

40 

50 

60 

70 

80 

Frequency (%) 

Hardbottom 

0-5 5-10 10-15 

Juveniles/subadults 

Mangrove 

15-20 20-25 

Unconsolidated 

Sediments 

25-30 30-35 >35 

Guanica 

Parguera 

Guanica 

Parguera 

b) 

d) 

0 

50 

100 

150 

200 

250 

300 

350 

400 

450 

500 

Mean biomass (#/100 m2 ) 

Hardbottom Mangrove Unconsolidated 

Sediments 

Guanica 

Parguera 

c) 

Figure 2.48. a) Spatial distribution, b) mean (±SE) density by habitat, c) mean (±SE) biomass by habitat and d) size (cm) frequency of 

French grunt (Haemulon flavolineatum). 

43 
0

2

4

6

8

10

12

Hardbottom Mangrove Unconsolidated

Sediments

Mean density (#/100 m2)

0

100

200

300

400

500

600

700

Hardbottom Mangrove Unconsolidated

Sediments

Mean biomass (#/100 m2)

Guanica

Parguera

0

10

20

30

40

50

60

70

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35

Frequency (%)

Guanica

Parguera

0

2

4

6

8

10

12

Hardbottom Mangrove Unconsolidated

Sediments

Mean density (#/100 m2)

Guanica

Parguera

0

100

200

300

400

500

600

700

Hardbottom Mangrove Unconsolidated

Sediments

Mean biomass (#/100 m2)

Guanica

Parguera

0

10

20

30

40

50

60

70

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35

Frequency (%)

0

2

4

6

8

10

12

Hardbottom Mangrove Unconsolidated

Sediments

Mean density (#/100 m2)

Guanica

Parguera

0

100

200

300

400

500

600

700

Hardbottom Mangrove Unconsolidated

Sediments

Mean biomass (#/100 m2)

0

10

20

30

40

50

60

70

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35

Frequency (%)

Guanica

Parguera

Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Fish and Benthic Communities 

Bluestriped grunt was sighted in 20% and 18% of surveys within the Guánica and La Parguera study areas, respectively. 

The species was most abundant in mangrove habitat; similarly biomass was also highest in mangrove habitat within the 

La Parguera study area (Figure 2.49a-c). Within the Guánica study area, mean biomass was similar on hardbottom and 

mangrove and exhibited high spatial variability. While all size classes were present in mangroves, juveniles/sub-adults 

were most common. Hardbottom was typically inhabited by the larger size classes. 

a) 

0 

2 

4 

6 

8 

10 

12 

14 

16 

Mean density (#/100 m2 ) 

0 

5 

10 

15 

20 

25 

30 

35 

Frequency (%) 

Hardbottom 

0-5 5-10 10-15 

Juveniles/subadults 

Mangrove 

15-20 20-25 

Unconsolidated 

Sediments 

25-30 30-35 >35 

Guanica 

Parguera 

Guanica 

Parguera 

b) 

d) 

0 

100 

200 

300 

400 

500 

600 

Mean biomass (#/100 m2 ) 

Hardbottom Mangrove Unconsolidated 

Sediments 

Guanica 

Parguera 

c) 

44 

Figure 2.49. a) Spatial distribution, b) mean (±SE) density by habitat, c) mean (±SE) biomass by habitat and d) size (cm) frequency of 

bluestriped grunt (Haemulon sciurus). 
0

2

4

6

8

10

12

Hardbottom Mangrove Unconsolidated

Sediments

Mean density (#/100 m2)

0

100

200

300

400

500

600

700

Hardbottom Mangrove Unconsolidated

Sediments

Mean biomass (#/100 m2)

Guanica

Parguera

0

10

20

30

40

50

60

70

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35

Frequency (%)

Guanica

Parguera

0

2

4

6

8

10

12

Hardbottom Mangrove Unconsolidated

Sediments

Mean density (#/100 m2)

Guanica

Parguera

0

100

200

300

400

500

600

700

Hardbottom Mangrove Unconsolidated

Sediments

Mean biomass (#/100 m2)

Guanica

Parguera

0

10

20

30

40

50

60

70

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35

Frequency (%)

0

2

4

6

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10

12

Hardbottom Mangrove Unconsolidated

Sediments

Mean density (#/100 m2)

Guanica

Parguera

0

100

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400

500

600

700

Hardbottom Mangrove Unconsolidated

Sediments

Mean biomass (#/100 m2)

0

10

20

30

40

50

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70

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35

Frequency (%)

Guanica

Parguera

Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Fish and Benthic Communities 

White grunt was present across all bottom types in the La Parguera study area and only on hardbottom and mangrove 

habitats within the Guánica study area (Figure 2.50). Small juveniles were most common in mangrove habitat, but in 

lower densities than the previously described grunt species. In the La Parguera study area, the majority of individuals 

were juveniles/subadults. In contrast, a larger proportion of observed fish, about 60% of the total, were adult-sized in the 

Guánica study area. 

a) 

0 

0.1 

0.2 

0.3 

0.4 

0.5 

0.6 

0.7 

0.8 

0.9 

1 

Mean density (#/100 m2 ) 0 

5 

10 

15 

20 

25 

30 

35 

40 

45 

Frequency (%) 

Hardbottom 

0-5 5-10 10-15 

Juveniles/subadults 

Mangrove 

15-20 20-25 

Unconsolidated 

Sediments 

25-30 30-35 >35 

Guanica 

Parguera 

Guanica 

Parguera 

b) 

d) 

0 

20 

40 

60 

80 

100 

120 

140 

160 

180 

Mean biomass (#/100 m2) 

Hardbottom Mangrove Unconsolidated 

Sediments 

Guanica 

Parguera c) 

Figure 2.50. a) Spatial distribution, b) mean (±SE) density by habitat, c) mean (±SE) biomass by habitat and d) size (cm) frequency of 

white grunt (Haemulon plumierii). 

45 
0

2

4

6

8

10

12

Hardbottom Mangrove Unconsolidated

Sediments

Mean density (#/100 m2)

0

100

200

300

400

500

600

700

Hardbottom Mangrove Unconsolidated

Sediments

Mean biomass (#/100 m2)

Guanica

Parguera

0

10

20

30

40

50

60

70

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35

Frequency (%)

Guanica

Parguera

0

2

4

6

8

10

12

Hardbottom Mangrove Unconsolidated

Sediments

Mean density (#/100 m2)

Guanica

Parguera

0

100

200

300

400

500

600

700

Hardbottom Mangrove Unconsolidated

Sediments

Mean biomass (#/100 m2)

Guanica

Parguera

0

10

20

30

40

50

60

70

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35

Frequency (%)

0

2

4

6

8

10

12

Hardbottom Mangrove Unconsolidated

Sediments

Mean density (#/100 m2)

Guanica

Parguera

0

100

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300

400

500

600

700

Hardbottom Mangrove Unconsolidated

Sediments

Mean biomass (#/100 m2)

0

10

20

30

40

50

60

70

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35

Frequency (%)

Guanica

Parguera

Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Fish and Benthic Communities 

In the Guánica study area, tomate was only documented at three hardbottom sites near the shelf edge, whereas in the La 

Parguera study area the species was observed at multiple sites spanning the shelf and bottom types, including nearshore 

and lagoon areas. The species was generally observed at low densities and biomass, with the exception of two offshore 

hardbottom sites where 17 and 49 individuals were observed (Figure 2.51a-c). There was no significant difference in 

biomass or density between study areas for the three surveyed habitats (Table 2.4). The majority of observed individuals 

were sub- adults/small adults, with few small juveniles or large adults (Figure 2.51d). 

0 

0.2 

0.4 

0.6 

0.8 

1 

1.2 

1.4 

1.6 

Hardbottom Mangrove Unconsolidated 

Sediments 

Mean density (#/100 m2 ) 

0 

20 

40 

60 

80 

100 

120 

140 

160 

Hardbottom Mangrove Unconsolidated 

Sediments 

Mean biomass (#/100 m2 ) 

0 

10 

20 

30 

40 

50 

60 

70 

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35 

Frequency (%) 

Juveniles/subadults 

Guanica 

Parguera 

Guanica 

Parguera 

Guanica 

Parguera 

c) 

a) 

b) 

d) 

46 

Figure 2.51. a) Spatial distribution, b) mean (±SE) density by habitat, c) mean (±SE) biomass by habitat and d) size (cm) frequency 

of tomtate (Haemulon aurolineatum). 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Fish and Benthic Communities 

Surgeonfish (Acanthuridae) 

Surgeonfish (acanthurids) were present in all three habitat types but most abundant in hardbottom habitats (Figure 2.52). 

In the Guánica study area in particular, fish in the family were more prevalent on the outer shelf than at hardbottom 

sites in the shallow lagoonal areas. Although sites with the highest abundance were observed in the La Parguera study 

area, mean density and biomass were not significantly different between the two regions (Table 2.4). Ocean surgeonfish 

(Acanthurus bahianus) and blue tang (A. coeruleus) were the most frequently observed species in both study areas, while 

doctorfish (A. chirirgus) were less common (Appendix A, Tables A.1, A.2). 

a) 

0 

2 

4 

6 

8 

10 

12 

Mean density (#/100 m2 ) 0 

10 

20 

30 

40 

50 

60 

70 

Frequency (%) 

Hardbottom Mangrove 

0-5 5-10 10-15 15-20 20-25 

Unconsolidated 

Sediments 

Guanica 

Parguera 

25-30 30-35 >35 

Guanica 

Parguera 

b) 

d) 

0 

100 

200 

300 

400 

500 

600 

700 

Mean biomass (#/100 m2 ) 

Hardbottom Mangrove Unconsolidated 

Sediments 

Guanica 

Parguera c) 

Figure 2.52. a) Spatial distribution, b) mean (±SE) density by habitat, c) mean (±SE) biomass by habitat and d) size (cm) frequency of 

surgeonfishes (Family Acanthuridae). 

47 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Fish and Benthic Communities 

Ocean surgeonfish were documented in 39% and 43% of surveys within the Guánica and La Parguera study areas, 

respectively. The species was observed across the study area, but species density and biomass were highest on hardbottom habitat outside lagoonal areas (Figure 2.53a-c). The majority of individuals in both study areas were juveniles/ 

sub-adults (Figure 2.53d). 

a) 

0 

1 

2 

3 

4 

5 

6 

7 

8 

Mean density (#/100 m2 ) 

0 

10 

20 

30 

40 

50 

60 

70 

Frequency (%) 

Hardbottom 

0-5 5-10 10-15 

Juveniles/subadults 

Mangrove 

15-20 20-25 

Unconsolidated 

Sediments 

Guanica 

Parguera 

25-30 30-35 >35 

Guanica 

Parguera 

b) 

d) 

0 

50 

100 

150 

200 

250 

300 

350 

Mean biomass (#/100 m2 ) 

Hardbottom Mangrove Unconsolidated 

Sediments 

Guanica 

Parguera c) 

48 

Figure 2.53. a) Spatial distribution, b) mean (±SE) density by habitat, c) mean (±SE) biomass by habitat and d) size (cm) frequency of 

ocean surgeonfish (Acanthurus bahianus). 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Fish and Benthic Communities 

Blue tang occurred in 30% and 27% of surveys within the Guánica and La Parguera stuyd areas, respectively, and exhibited a similar distribution to ocean surgeonfish (Figure 2.54). The species was absent from mangrove habitat in the La 

Parguera study area and from unconsolidated sediment surveys in the Guánica study area. The majority of individuals 

were small adults (10-20 cm in total length), with fewer numbers of small juveniles or large adults (Figure 2.54d). 

0 

0.5 

1 

1.5 

2 

2.5 

3 

3.5 

4 

4.5 

Hardbottom Mangrove Unconsolidated 

Sediments 

Mean density (#/100 m2) 

Guanica 

Parguera 

0 

50 

100 

150 

200 

250 

300 

350 

Hardbottom Mangrove Unconsolidated 

Sediments 

Mean biomass (#/100 m2 ) 

Guanica 

Parguera 

0 

10 

20 

30 

40 

50 

60 

70 

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35 

Frequency (%) 

Guanica 

Parguera 

Juveniles/subadults 

c) 

a) 

b) 

d) 

Figure 2.54. a) Spatial distribution, b) mean (±SE) density by habitat, c) mean (±SE) biomass by habitat and d) size (cm) frequency 

of blue tang (Acanthurus coeruleus). 

49 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Fish and Benthic Communities 

Parrotfish (Scaridae) 

Parrotfishes (Family Scaridae) were a common component of the southwest Puerto Rico fish community. The family was 

represented by 11 species, nine of which were present in both study areas and two of which were only recorded in the 

La Parguera study area (Appendix A, Tables A.1, A.2). In both areas, the species with the highest site frequency, density 

and biomass were striped parrotfish (Scarus iseri), redband parrotfish (Sparisoma aurofrenatum), princess parrotfish 

(Sc. taeniopterus) and stoplight parrotfish (Sp. viride). Larger-bodied species, such as midnight parrotfish (Sc. coeruleus) 

and rainbow parrotfish (Sc. guacamaia), were absent from both study areas. Highest levels of density and biomass were 

generally observed on hardbottom habitat, with variable density in mangrove habitats (Figure 2.55a-c). Generally small 

juveniles were prevalent in mangroves (Figure 2.55d), hence biomass in this habitat was relatively low. On hardbottom, 

Scaridae biomass and density were significantly greater in La Parguera than the Guánica study area (Table 2.4). In the La 

Parguera study area, 42% of the hardbottom sites had a parrotfish density >25 individuals/100 m2, compared to only 7% 

of sites within the Guánica study area. In La Parguera, these “high” density sites were distributed across the shelf, while 

in Guánica they were restricted to the shelf edge (Figure 2.55a). 

a) 

20 

25 

30 

2 ) #/100 m

Guanica 

Parguera b) 

800 

1000 

1200 

#/100 m

Guanica 

Parguera c) 

0 

5 

10 

15

Mean density (

0 

200 

400 

600 

Mean biomass ( 2 ) 

Hardbottom Mangrove Unconsolidated 

Sediments 

Hardbottom Mangrove Unconsolidated 

Sediments 

60 

50 

Guanica 

Parguera d) 

40

(%) 30 Frequency 

20 

0 

10 

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35 

50 

Figure 2.55. a) Spatial distribution, b) mean (±SE) density by habitat, c) mean (±SE) biomass by habitat and d) size (cm) frequency of 

parrotfish (Family Scaridae). 
0

2

4

6

8

10

12

Hardbottom Mangrove Unconsolidated

Sediments

Mean density (#/100 m2)

0

100

200

300

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700

Hardbottom Mangrove Unconsolidated

Sediments

Mean biomass (#/100 m2)

Guanica

Parguera

0

10

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40

50

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70

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35

Frequency (%)

Guanica

Parguera

0

2

4

6

8

10

12

Hardbottom Mangrove Unconsolidated

Sediments

Mean density (#/100 m2)

Guanica

Parguera

0

100

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400

500

600

700

Hardbottom Mangrove Unconsolidated

Sediments

Mean biomass (#/100 m2)

Guanica

Parguera

0

10

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40

50

60

70

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35

Frequency (%)

0

2

4

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10

12

Hardbottom Mangrove Unconsolidated

Sediments

Mean density (#/100 m2)

Guanica

Parguera

0

100

200

300

400

500

600

700

Hardbottom Mangrove Unconsolidated

Sediments

Mean biomass (#/100 m2)

0

10

20

30

40

50

60

70

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35

Frequency (%)

Guanica

Parguera

Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Fish and Benthic Communities 

Striped parrotfish were present in 26% and 49% of surveys within the Guánica and La Parguera study areas, respectively. 

On hardbottom habitats, the species exhibited significantly higher density and biomass in the La Parguera study area 

(Table 2.4). There was an opposite trend in mangrove habitat, where the species exhibited higher density and biomass 

in the Guánica study area, however these differences were not statistically significant (Table 2.4 and Figure 2.56b,c). 

This species was largely limited to offshore hardbottom and nearshore mangroves in the Guánica study area, while in La 

Parguera it was distributed across the mid-outer shelf, primarily in hardbottom habitats (Figure 2.56a). In Guánica, the 

majority of individuals (>80%) were small juveniles (<5 cm), most of which were observed in mangrove habitat (Figure 

2.56d). In contrast, the size distribution in the La Parguera study area included greater proportions of larger juveniles and 

small adults. 

a) 

0 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

Mean density (#/100 m2 ) 0 

5 

10 

15 

20 

25 

30 

35 

40 

Frequency (%) 

Hardbottom 

0-5 5-10 10-15 

Juveniles/subadults 

Mangrove 

15-20 20-25 

Unconsolidated 

Sediments 

25-30 30-35 >35 

Guanica 

Parguera 

Guanica 

Parguera 

b) 

d) 

0 

50 

100 

150 

200 

250 

300 

Mean biomass (#/100 m2 ) 

Hardbottom Mangrove Unconsolidated 

Sediments 

Guanica 

Parguera 

c) 

Figure 2.56. a) Spatial distribution, b) mean (±SE) density by habitat, c) mean (±SE) biomass by habitat and d) size (cm) frequency of 

striped parrotfish (Scarus iseri). 

51 
0

2

4

6

8

10

12

Hardbottom Mangrove Unconsolidated

Sediments

Mean density (#/100 m2)

0

100

200

300

400

500

600

700

Hardbottom Mangrove Unconsolidated

Sediments

Mean biomass (#/100 m2)

Guanica

Parguera

0

10

20

30

40

50

60

70

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35

Frequency (%)

Guanica

Parguera

0

2

4

6

8

10

12

Hardbottom Mangrove Unconsolidated

Sediments

Mean density (#/100 m2)

Guanica

Parguera

0

100

200

300

400

500

600

700

Hardbottom Mangrove Unconsolidated

Sediments

Mean biomass (#/100 m2)

Guanica

Parguera

0

10

20

30

40

50

60

70

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35

Frequency (%)

0

2

4

6

8

10

12

Hardbottom Mangrove Unconsolidated

Sediments

Mean density (#/100 m2)

Guanica

Parguera

0

100

200

300

400

500

600

700

Hardbottom Mangrove Unconsolidated

Sediments

Mean biomass (#/100 m2)

0

10

20

30

40

50

60

70

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35

Frequency (%)

Guanica

Parguera

Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Fish and Benthic Communities 

Redband parrotfish were sighted in about 50% of survey transects in both study areas. However, similar to the previous 

species, density and biomass on hardbottom were significantly greater in the La Parguera study area compared to the 

Guánica study area (Table 2.4). Redband parrotfish were uncommon on unconsolidated sediment and mangrove habitats 

(Figure 2.57a,b). In both study areas, the size distribution was skewed towards the smaller size classes (0-10 cm total 

length) while 30% and 40% of individuals were small adults in the Guánica and La Parguera study areas, respectively 

(Figure 2.57d). 

a) 

0 

1 

2 

3 

4 

5 

6 

7 

8 

9 

10 

Mean density (#/100 m2 ) 

0 

5 

10 

15 

20 

25 

30 

35 

40 

Frequency (%) 

Hardbottom 

0-5 5-10 10-15 

Juveniles/subadults 

Mangrove 

15-20 20-25 

Unconsolidated 

Sediments 

25-30 30-35 >35 

b) 

d) 

Guanica 

Parguera 

Guanica 

Parguera 

0 

50 

100 

150 

200 

250 

300 

Mean biomass (#/100 m2 ) 

Hardbottom Mangrove Unconsolidated 

Sediments 

c) Guanica 

Parguera 

52 

Figure 2.57. a) Spatial distribution, b) mean (±SE) density by habitat, c) mean (±SE) biomass by habitat and d) size (cm) frequency of 

redband parrotfish (Sparisoma aurofrenatum). 
0

2

4

6

8

10

12

Hardbottom Mangrove Unconsolidated

Sediments

Mean density (#/100 m2)

Guanica

Parguera

0

100

200

300

400

500

600

700

Hardbottom Mangrove Unconsolidated

Sediments

Mean biomass (#/100 m2)

Guanica

Parguera

0

10

20

30

40

50

60

70

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35

Frequency (%) 0

2

4

6

8

10

12

Hardbottom Mangrove Unconsolidated

Sediments

Mean density (#/100 m2)

Guanica

Parguera

0

100

200

300

400

500

600

700

Hardbottom Mangrove Unconsolidated

Sediments

Mean biomass (#/100 m2)

0

10

20

30

40

50

60

70

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35

Frequency (%)

Guanica

Parguera

Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Fish and Benthic Communities 

Stoplight parrotfish were observed in all three habitats but exhibited highest abundance and biomass on hardbottom 

habitat (Figure 2.58a-c). Species density was greater on hardbottom within the La Parguera study area compared to 

Guánica, but the nonparametric tests indicated no statistical difference in density or biomass between the two study areas 

(Table 2.4). The size distribution was more heterogeneous than the previous two parrotfish species, with a mix of small 

juveniles-small adults (Figure 2.58d). In addition, three large adults (40 cm total length) were observed in the La Parguera 

study area. 

a) 

0 

0.5 

1 

1.5 

2 

2.5 

3 

3.5 

Mean density (#/100 m2 ) 

0 

5 

10 

15 

20 

25 

30 

35 

40 

Frequency (%) 

Hardbottom 

0-5 5-10 10-15 

Juveniles/subadults 

Mangrove 

15-20 20-25 

Unconsolidated 

Sediments 

Guanica 

Parguera 

25-30 30-35 >35 

b) 

d) Guanica 

Parguera 

0 

50 

100 

150 

200 

250 

300 

350 

400 

450 

Mean biomass (#/100 m2 ) 

Hardbottom Mangrove 

c) 

Unconsolidated 

Sediments 

Guanica 

Parguera 

Figure 2.58. a) Spatial distribution, b) mean (±SE) density by habitat, c) mean (±SE) biomass by habitat and d) size (cm) frequency of 

stoplight parrotfish (Sparisoma viride). 

53 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Fish and Benthic Communities 

Wrasses (Labridae) 

Wrasses were commonly sighted, occurring in 77% and 64% of surveys in the Guánica and La Parguera study areas, 

respectively, and nearly all hardbottom surveys. Although observed throughout the study area, sites with the highest 

densities tended to be located on the mid-outer shelf (Figure 2.59a). On hardbottom, there was a statistical difference in 

abundance and biomass between the two study areas (Table 2.4) with the Guánica study area exhibiting higher levels of 

abundance and biomass (Figure 2.59b,c). The family was represented by 13 species, 10 of which were observed in both 

study areas (Appendix A, Tables A.1, A.2). Two additional species were sighted only in the La Parguera study area and 

one was unique to the Guánica study area. Bluehead (Thalassoma bifasciatum) was the most abundant species in both 

study areas. Hogfish (Lachnolaimus maximus), an economically important species in Puerto Rico, were present in only 

one survey transect in the Guánica study area and a handful of survey transects in the La Parguera study area. The size 

distribution skewed towards the smaller size classes (Figure 2.59d) because small-bodied wrasse species were most 

abundant. 

a) 

0 

5 

10 

15 

20 

25 

30 

35 

40 

45 

50 

Mean density (#/100 m2 )

0 

10 

20 

30 

40 

50 

60 

70 

Frequency (%) 

Hardbottom Mangrove 

0-5 5-10 10-15 15-20 20-25 

Unconsolidated 

Sediments 

Guanica 

Parguera 

25-30 30-35 >35 

Guanica 

Parguera 

b) 

d) 

0 

50 

100 

150 

200 

250 

300 

350 

Mean biomass (#/100 m2 )

Hardbottom Mangrove Unconsolidated 

Sediments 

Guanica 

Parguera c) 

54 

Figure 2.59. a) Spatial distribution, b) mean (±SE) density by habitat, c) mean (±SE) biomass by habitat and d) size (cm) frequency of 

wrasses (Family Labridae). 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Fish and Benthic Communities 

Goatfishes (Mullidae) 

Fishes of the Family Mullidae were present in 8% and 20% of survey transects within the Guánica and La Parguera study 

areas, respectively. The family was represented by two species, spotted goatfish (Pseudupeneus maculatus) and yellow 

goatfish (Mulloidichthys martinicus). In the Guánica study area, the family was only observed on hardbottom and generally in low numbers, with the exception of two offshore hardbottom surveys where larger groups of yellow goatfish were 

observed (Figure 2.60a). In the La Parguera study area, most occurrences of mullids also occurred on hardbottom in the 

mid-outer shelf. The size distribution varied slightly between the two study areas; the majority of individuals in the Guánica 

study area were within the 20-25 cm size class, while the majority of individuals observed in the La Parguera study area 

were 10-20 cm in length (Figure 2.60d). 

a) 

0 

0.5 

1 

1.5 

2 

2.5 

Mean density (#/100 m2 ) 0 

10 

20 

30 

40 

50 

60 

70 

80 

90 

Frequency (%) 

Hardbottom 

0-5 5-10 10-15 

Mangrove 

15-20 20-25 

Unconsolidated 

Sediments 

Guanica 

Parguera 

25-30 30-35 >35 

Guanica 

Parguera 

b) 

d) 

0 

100 

200 

300 

400 

500 

600 

Mean biomass (#/100 m2 )

Hardbottom Mangrove Unconsolidated 

Sediments 

Guanica 

Parguera c) 

Figure 2.60. a) Spatial distribution, b) mean (±SE) density by habitat, c) mean (±SE) biomass by habitat and d) size (cm) frequency of 

goatfish (Family Mullidae). 

55 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Fish and Benthic Communities 

Damselfishes (Pomacentridae) 

Damselfishes were present across all bottom types, occurring in 61% and 76% of surveys within the Guánica and La Parguera study areas, respectively. Highest densities and biomass were observed on hardbottom, with intermediate levels 

in mangrove habitat (Figure 2.61a-c). The family was represented by 11 species, with nine common to both study areas 

and two observed only in the La Parguera study area (Appendix A ,Tables A.1, A.2). Frequently observed species included the bicolor damselfish (Stegastes partitus) and beaugregory (S. leucostictus). On hardbottom, damselfishes were 

significantly more abundant within the Guánica study area (Table 2.4). This was likely due to large numbers of bicolor 

damselfish at several locations on the outer shelf in the Guánica study area. However, biomass did not vary significantly 

between the two study regions. 

0 

5 

10 

15 

20 

25 

30 

35 

Hardbottom Mangrove Unconsolidated 

Sediments 

Mean density (#/100 m2 ) 

Guanica 

Parguera 

0 

20 

40 

60 

80 

100 

120 

140 

160 

Hardbottom Mangrove Unconsolidated 

Sediments 

Mean biomass (#/100 m2 )

Guanica 

Parguera 

0 

10 

20 

30 

40 

50 

60 

70 

80 

0-5 5-10 10-15 15-20 20-25 25-30 30-35 >35 

Frequency (%) 

Guanica 

Parguera 

a) 

b) c) 

d) 

56 

Figure 2.61. a) Spatial distribution, b) mean (±SE) density by habitat, c) mean (±SE) biomass by habitat and d) size (cm) frequency of 

damselfishes (Family Pomacentridae). 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

57 Fish and Benthic Communities 

ConClusions 

The results of this study provide a baseline characterization of the fish and benthic communities of Guánica Bay to assess the efficacy of the watershed restoration efforts. Comparisons were made in the metrics between the Guánica and 

La Parguera study areas to investigate potential differences in the adjacent regions. For the purposes of this study, the 

region of southwest Puerto Rico was treated as two study areas; however the Guánica and La Parguera study areas are 

effectively part of the same continuous system. The prevailing surface currents are driven by the trade winds and flow 

westward, meaning that effluent from Guánica Bay flows downstream towards the La Parguera region. In addition, the 

new benthic habitat map of southwest Puerto Rico includes a region south of the current La Parguera study area that was 

previously unmapped (Bauer et al., 2012). This area contains 28 km2 of coral reef and hardbottom extending out to the 

shelf edge, about one-third of which is high rugosity spur and groove structure. It is recommended that the entire system, 

including this newly mapped area, continue to be monitored in future sampling efforts. 

While most metrics observed in this study were similar between the two regions, there is some evidence that the Guánica 

study area is more degraded than La Parguera. While coral cover was generally low across the entire study region, it 

was significantly higher in the La Parguera study area. Gorgonian and seagrass cover were similarly higher in the La 

Parguera study area. Differences in benthic habitat composition may be a factor influencing these differences. However, 

previous work also indicates that levels of some contaminants exhibit a downstream gradient with higher levels near the 

mouth of Guánica Bay (see Chapter 3 in this document; Pait et al., 2009). Linkages between chemical contaminants and 

coral health are poorly understood (Pait et al., 2009) and understanding these cause and effect relationships are critical 

to effective management and restoration practices. 

Recent local studies highlight changes in the Guánica marine benthic community over time. Garcia-Sais et al. (2001) 

conducted a baseline assessment of the marine fauna at three locations southeast of Guánica Bay, moving west to east: 

Cayo Coral, Cayo de Cana Gorda and Punta Ventana. The community was dominated by gorgonians and soft corals, with 

high hard coral cover, averaging ≥25% at all three locations (Garcia-Sais et al., 2001). While these reefs were selected for 

a specific study purpose and may not be representative of the region as a whole, they recorded higher coral cover than 

was observed at any site within our Guánica study area (maximum 18.5%). Since the initial baseline survey conducted 

by Garcia et al. (2001), long-term monitoring has been conducted at their western most site, Cayo Coral. Percent hard 

coral cover decreased from a mean of 25.3% in 1999 to 8.9% in 2008, for an overall reduction of ~65% (Garcia-Sais et 

al., 2008b). In a subsequent survey, live coral cover had slightly increased to 10.0% (Garcia-Sais et al., 2009). Boulder 

star coral in particular showed marketed decline over this time period. 

As mentioned previously, while this is the first time that the Caribbean Coral Reef Ecosystem Monitoring Program study 

has extended as far east as Guánica Bay, the La Parguera region has been monitored one to two times/year since 2001. 

Pittman et al. (2010) conducted an analysis of fish and benthic data from La Parguera spanning from 2001-2007. This 

study noted a decrease in live scleractinian coral cover in comparison to the long-term average in Pittman et al. (2010). 

Coral cover averaged 5.3 ± 0.3% over the 2001-2007 time period, and exhibited a decreasing trend over time. By 2007, 

mean coral estimates were <5% cover (Pittman et al., 2010). Our results indicate that coral cover has continued to decline 

within the La Parguera region (4.0 ± 0.4% in the current study’s La Parguera study area from 2008-2010) and is even 

lower in the Guánica study area (2.2 ± 0.4%). 

According to Morelock et al. (2001), the Guánica Bay region historically has lower coral cover compared to La Parguera. 

Morelock et al. (2001) used photo transects to monitor coral cover along the southwest reefs of Puerto Rico, including 

Guánica, over a 20-year period starting in the late 1970s. They reported mean maximum coral cover at <10% on the 

Guánica shelf reefs and ~20% on the shelf edge reefs, with lowest cover present at Cayo Cana Gorda near the mouth of 

Guánica Bay. The data also showed declining trends in coral cover within the region, particularly from 1988-1999 due to 

increased sediment and nutrient loading from the bay. Warne et al. (2005) estimated the sediment discharge to the bay 

at 1,000-4,300 m tons/km2

 for the south coast of Puerto Rico, making the Guánica Bay/Rio Loco watershed one of the 

highest sources of sediment discharge around the island and the site of degraded reefs. 

A recent meta-analysis indicated that live coral cover in the Caribbean has declined by 80% over the last three decades 

(Gardner et al., 2003) which has subsequently led to a “flattening,” or decline in rugosity, of reefs over time (Alvarez-Filip 

et al., 2009). Elkhorn and staghorn coral, which were formerly dominant reef builders in shallow and intermediate forereef 

communities, respectively, have been devastated by white-band disease (Aronson and Precht, 2001). In Puerto Rico, 

recovery from the initial 1980s disease outbreak has been limited and Acroporid populations have declined significantly 

at locations island-wide where they were formerly abundant (Weil et al., 2002). Similarly, Acroporid species were sighted 

infrequently in this study. 

Boulder star coral, another major reef-building coral, has also experienced widespread declines (Edmonds and Elahi, 

2007), while the relative abundance of smaller, “weedy” species such as mustard hill coral has increased (Green et al. 

2008). While the boulder star coral complex was the number one and number four ranked species in terms of percent 

cover in the Guánica and La Parguera study areas, respectively, mean cover of this species was low, especially in the 

Guánica study area. Mustard hill coral ranked second in terms of percent cover in both study areas. Puerto Rican reefs 

also experienced additional declines in coral cover following a 2005 bleaching event (García-Sais et al., 2008a). 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Fish and Benthic Communities 

Comparisons across studies are confounded by sampling strategies and make it difficult to identify true environmental 

changes. Using data collected by the NCCOS Biogeography Branch, including the aforementioned Pittman et al. (2010), 

allows for more accurate regional comparisons on benthic cover over time due to the standardized survey methodology. 

Since 2001, the NCCOS Biogeography Branch has regularly monitored habitat and fish communities using the same survey methodology in other U.S. Caribbean locations, including the Buck Island Reef National Monument in St. Croix, U.S. 

Virgin Islands (Pittman et al., 2008), Vieques, Puerto Rico (Bauer and Kendall, 2010) and the Jobos Bay region (Bauer 

et al., 2011). Comparatively, reef and hardbottom benthic communities in the Guánica Bay have lower mean coral cover 

than other regions of Puerto Rico and the U.S. Virgin Islands (2.2%). Similar to the Pittman et al. (2010) assessment in 

La Parguera, hard coral cover in St. Croix averaged 5.6 ± 0.5% over 2001-2006 (Pittman et al., 2008). In Vieques, coral 

cover from a 2007 survey averaged 3.4 ± 0.5% (Bauer and Kendall, 2010), while in the Jobos Bay 2009 survey, coral 

cover averaged 6.5 (±1.2)% (Bauer et al., 2011). At all of these locations, turf algae and macroalgae were the dominant 

benthic cover types on reef and hardbottom. 

Both live coral cover and gorgonian cover were significantly higher in the La Parguera study area compared to Guánica, 

and both metrics were positively correlated with distance from the mouth of Guánica Bay. While correlation alone does 

not imply causation, more work is warranted to investigate whether there is a relationship between watershed variables 

and benthic cover metrics. In Palau, coral metrics (coral cover, richness and density) were positively related to distance 

from embayments and negatively related to increasing suspended solids (Golbuu et al., 2011). 

Fish communities were similar between the Table 2.5. Area summary of detailed geomorphological structure within the Guánica 

two study areas, with a few exceptions. On and La Parguera study areas from the new southwest Puerto Rico benthic habitat 

map (Bauer et al., 2012). hardbottom habitats, parrotfish were significantly more abundant in the La Parguera 

study area, while wrasses and damselfish 

were significantly more abundant in the 

Guánica study area. Parrotfish abundance 

and biomass were particularly low in areas 

south and east of Guánica Bay. The reasons behind this pattern are unknown but 

could be influenced by a number of factors, 

including species competition, differences 

in habitat type, and local fishing pressure. 

In the Guánica study area, pavement is 

the dominant hardbottom type, comprising 30.7% of the total area and three-fifths 

of the total hardbottom (Table 2.5). Higher 

complexity aggregate reef, in contrast, 

comprised only 13% of the total hardbottom 

within the Guánica study area. In contrast, 

within the La Parguera study area, high rugosity reef types (aggregate reef, spur and 

groove, patch reefs) altogether comprised 

~48% of the total hardbottom. Density of total Scaridae was positively correlated with 

fine-scale rugosity measurements from this 

study (Spearman’s Rho = 0.47, p<0.0001). 

Previous studies have also shown positive relationships between topographic complexity and parrotfish metrics, including overall parrotfish biomass (Pittman et al., 2009), Scarus iserti abundance (Mumby and Wabnitz, 2002) and Sc. taeniopterus distribution (Pittman and Brown, 2011). However, despite the differences in composition of detailed hardbottom 

detailed geomorphological 

structure 

guánica 

study Area 

la Parguera 

study Area 

Area 

(km2

) 

Percent 

of Area 

Area 

(km2) 

Percent 

of Area 

Aggregate Reef 5 6.7 13 12.4 

Aggregated Patch Reefs 2 2.6 7 6.1 

Individual Patch Reef 1 1.1 1 1.0 

Mud 6 7.8 24 22.2 

Pavement 23 30.7 7 6.5 

Pavement with Sand Channels 5 6.0 16 14.7 

Reef Rubble 2 2.5 2 2.1 

Rock/Boulder 0.1 0.1 0.01 0.0 

Sand 25 33.1 32 29.5 

Sand with Scattered Coral and 

Rock 

6 7.9 4 3.7 

Spur and Groove 1 1.5 2 1.8 

total 76 100 108 100 

structure, mean fine-scale rugosity was similar on hardbottom sites between the two study areas. Further data collection 

may elucidate whether the patterns observed here are persistent over time or were an anomaly. 

Pittman et al. (2010) provides a summary and analysis of the fish community data in La Parguera from 2001-2007. Due 

to the similarity in the two study areas, interannual trends observed in the La Parguera study area may be indicative of 

patterns in the Guánica region. While overall grouper biomass was significantly lower in 2007 compared to 2001, other 

metrics, including species richness, total biomass, total grouper abundance, graysby abundance and biomass, and parrotfish abundance and biomass increased over the same time period (Pittman et al., 2010). The increase in small-bodied 

groupers such as graysby were thought to be influenced by the decline of larger bodied grouper species (Pittman et al., 

2010), as in Stallings (2008). Similar to Pittman et al. (2010), in this study the dominant Serranid species included graysby 

and coney, and a few red hind and rock hind. 

However, as Pittman et al. (2010) note, it is likely that the most significant ecosystem changes occurred prior to the start of 

the monitoring in 2001. The U.S. Caribbean has been subject to region-wide stresses that have affected the wider Caribbean in the last few decades, including a widespread die-off of long-spined urchin in the 1980s, mass Acropora species 

mortality due to white band disease, coral bleaching, overfishing, and tropical cyclones. Caribbean region-wide declines 

58 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

59 Fish and Benthic Communities 

in fish abundance have been documented (Paddack et al., 2009). Hence, while one of our objectives is to conduct a 

“baseline” assessment of the Guánica Bay region, it is important to note that this is relative to current conditions. The lack 

of historical quantitative data leads to a “shifting baseline” away from “pristine” conditions over time (Pauly, 1995; Jackson 

et al., 2001). 

This project represents a unique opportunity to assess the effect of restoration activities on a coral reef ecosystem. 

Similar efforts that also seek to reduce degradation of reef environments are underway in Hawaii (Conservation Reserve 

Enhancement Program, http://www.fsa.usda.gov/) and Micronesia (Richmond et al., 2007). The proposed restoration 

activities, particularly the restoration of the Guánica lagoon, have a common goal of reducing anthropogenic inputs to 

the marine environment. Hence, it is likely that the most immediate benefits of restoration will be reduced sediment and 

nutrient loads in the upper reaches of the watershed closest to the sediment source, followed by reduced loadings into 

the bay and surrounding environment. 

While there is little in the literature that demonstrates the effects of restoration efforts on a reef ecosystem, it is possible 

that the reduction in stressor inputs will have a positive impact on coral reef health. For example, one potential effect is 

that reduced nutrient inputs could lead to a decline in cover of algal groups. Both macroalgae and cyanobacteria have 

been shown to inhibit coral recruitment (Kuffner et al., 2006), so reduction of these groups could, in theory, improve coral 

recruitment over time. Sediment runoff from the terrestrial environment, which is often accompanied by nutrients and a 

variety of land-based contaminants, has been found to have several negative impacts on hard corals, including direct 

smothering and light reduction due to turbidity. This can lead to decreased photosynthesis, growth, reproduction and recruitment rates, although the effects vary among coral species, sediment types, and environmental conditions (Rogers, 

1990; Fabricius, 2005). A coral’s ability to compensate for elevated turbidity is related to water depth such that in turbid 

environments, coral growth is restricted to shallower water (Yentsch et al., 2002). Although more research has been conducted regarding hard corals’ sensitivity to sedimentation, octocorals are also sensitive to sediments (Riegl and Branch, 

1995). While the effects of sedimentation on coral reef fishes are not well known, recent experimental work indicated that, 

as suspended sediment concentrations increase, larval damselfish are less able to discriminate between preferred settlement sites (Wenger et al., 2011). Hence, decreased sediment and associated nutrients/contaminants may reduce stress 

on fish and benthic biota. 

However, it is also possible that improvement to biological metrics such as live coral cover and fish abundance may ultimately require a reduction in multiple stressors, many of which are present at not only local but also regional and global 

scales (e.g., climate change, ocean acidification, overfishing). While land-based sources of pollution are widely attributed 

to be a contributing factor to coral reef decline (e.g., Warne et al., 2005; Waddell and Clarke, 2008), identifying the relative contribution of individual anthropogenic activities to reef degradation is challenging (Downs et al., 2005; Fabricius, 

2005; Wolanski et al., 2009). Even prior to widespread coral dieoff in the 1980s, the reefs in Guánica were reported to be 

in poorer condition than nearby La Parguera (Goenaga and Cintron, 1979; Morelock et al., 2001). Whether reduced sediment inputs alone are enough to foster improvements to coral health in the Guánica region are unknown. 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

60 Fish and Benthic Communities 

RefeRenCes 

Alvarez-Filip, L., N.K. Dulvy, J.A. Gill, I.M. Côte, and A.R. Watkinson. 2009. Flattening of Caribbean coral reefs: region-wide declines in 

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Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Contaminants 

Chapter 3: Contaminants in Surficial Sediments

and Coral tissues of guánica bay 

David Whitall1, Andrew Mason1, Lia Brune1,Anthony Pait1, 

Michael Fulton1, Ed Wirth1, Lisa Vandiver2 and Matthew Poti1,3
 

ContAminAnt bACkgRound 

Chemical Contaminants Analyzed

Since 1986, NOAA’s National Status and Trends (NS&T) Program has monitored and assessed the nation’s estuarine and 

coastal waters for chemical contaminants in a variety of matrices (e.g., bivalve tissues, sediments). Characterization of 

contaminants in coral reefs by NS&T began in 2005. The suite of chemical contaminants routinely analyzed by NS&T and 

analyzed in the coral tissue and sediment samples for this project is shown in Table 3.1. The analytes include 58 polycyclic 

aromatic hydrocarbons (PAHs), 31 organochlorine pesticides, 38 polychlorinated biphenyls (PCBs), four butyltins, and 16 

trace and major elements. All samples were analyzed using NS&T standard protocols. The analytical protocols have been 

published previously (Kimbrough et al., 2006; Kimbrough and Lauenstein, 2006). The nature, sources and environmental 

significance of each of the contaminant classes analyzed for this project are discussed below. 

Table 3.1 List of analytes. 

PAhs - low molecular Weight PAhs - high molecular Weight PCbs organochlorine 

Pesticides 

Naphthalene* Fluoranthene* PCB8/5 Aldrin 

1-Methylnaphthalene* Pyrene* PCB18 Dieldrin 

2-Methylnaphthalene* C1-Fluoranthenes/Pyrenes PCB28 Endrin 

2,6-Dimethylnaphthalene* C2-Fluoranthenes/Pyrenes PCB29 Heptachlor 

1,6,7-Trimethylnaphthalene* C3-Fluoranthenes/Pyrenes PCB31 Heptachlor-Epoxide 

C1-Naphthalenes Naphthobenzothiophene PCB44 Oxychlordane 

C2-Naphthalenes C1-Naphthobenzothiophenes PCB45 Alpha-Chlordane 

C3-Naphthalenes C2-Naphthobenzothiophenes PCB49 Gamma-Chlordane 

C4-Naphthalenes C3-Naphthobenzothiophenes PCB52 Trans-Nonachlor 

Benzothiophene Benz(a)anthracene* PCB56/60 Cis-Nonachlor 

C1-Benzothiophenes Chrysene* PCB66 Alpha-HCH 

C2-Benzothiophenes C1-Chrysenes PCB70 Beta-HCH 

C3-Benzothiophenes C2-Chrysenes PCB74/61 Delta-HCH 

Biphenyl* C3-Chrysenes PCB87/115 Gamma-HCH 

Acenaphthylene* C4-Chrysenes PCB95 2,4'-DDT 

Acenaphthene* Benzo(b)fluoranthene* PCB99 4,4'-DDT 

Dibenzofuran Benzo(k)fluoranthene* PCB101/90 2,4'-DDD 

Fluorene* Benzo(e)pyrene* PCB105 4,4'-DDD 

C1-Fluorenes Benzo(a)pyrene* PCB110/77 2,4'-DDE 

C2-Fluorenes Perylene* PCB118 4,4'-DDE 

C3-Fluorenes Indeno(1,2,3-c,d)pyrene* PCB128 DDMU 

Anthracene* Dibenzo(a,h)anthracene* PCB138/160 1,2,3,4-Tetrachlorobenzene 

Phenanthrene* C1-Dibenzo(a,h)anthracenes PCB146 1,2,4,5-Tetrachlorobenzene 

1-Methylphenanthrene* C2-Dibenzo(a,h)anthracenes PCB149/123 Hexachlorobenzene 

C1-Phenanthrene/Anthracenes C3-Dibenzo(a,h)anthracenes PCB151 Pentachloroanisole 

C2-Phenanthrene/Anthracenes Benzo(g,h,i)perylene* PCB153/132 Pentachlorobenzene 

C3-Phenanthrene/Anthracenes PCB156/171/202 Endosulfan II 

1. NOAA/NOS/NCCOS

2. Earth Resources Technology Incorporated, Contractor to NOAA, National Marine Fisheries Service, Restoration Center

3. CSS-Dynamac, Fairfax, VA 

63 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Contaminants 

Table 3.1 (continued). List of analytes. 

PAhs - low molecular Weight PAhs - high molecular Weight PCbs organochlorine 

Pesticides 

C4-Phenanthrene/Anthracenes Trace Elements PCB158 Endosulfan I 

Dibenzothiophene Aluminum PCB170/190 Endosulfan Sulfate 

C1-Dibenzothiophenes Antimony PCB174 Mirex 

C2-Dibenzothiophenes Arsenic PCB180 Chlorpyrifos 

C3-Dibenzothiophenes Cadmium PCB183 

Chromium PCB187 Butyltins 

Copper PCB194 Monobutyltin 

Iron PCB195/208 Dibutyltin 

Lead PCB199 Tributyltin 

Manganese PCB201/157/173 Tetrabutyltin 

Mercury PCB206 

Nickel PCB209 

Selenium 

Silver 

Tin 

Zinc 

*Compounds used in the calculation of total PAHs 

PAHs = polycyclic aromatic hydrocarbons; PCBs = polychlorinated biphenyls 

Polycyclic aromatic hydrocarbons (PAHs) 

PAHs are associated with the use and combustion of fossil fuels and other organic materials (e.g., wood). Natural sources 

of PAHs include forest fires and volcanoes. The PAHs analyzed in this study are two to six ring aromatic compounds. 

Environmental Effects of PAHs 

Although an extensive amount of research has been done on the accumulation and effects of PAHs on aquatic organisms, 

relatively few studies have been conducted to address the effects of PAHs on corals. Hydrophobic in nature, PAHs readily 

accumulate in marine organisms through direct exposure (e.g., body surface, gills) or through the food chain (Neff,1985). 

PAH exposure has been associated with oxidative stress, immune system and endocrine system problems and developmental abnormalities in marine organisms (Hylland, 2006). 

Furthermore, a number of individual PAHs including benzo[a]pyrene, benz[a]anthracene, chrysene, benzo[b]fluoranthene, benzo[k]fluoranthene, dibenzo[a,h]anthracene and indeno[1,2,3-c,d]pyrene have been identified as likely carcinogens (USDHHS, 1995). The carcinogenic potential of PAHs in marine organisms is associated with their metabolic 

breakdown, which generates reactive epoxides that can bind to cellular components such as DNA (Hylland, 2006; Neff, 

1985). In addition to accumulating in the coral tissues themselves, PAHs can also affect the zooxanthellae, the symbiotic 

photosynthetic dinoflagellate algae found within coral tissues. Bioaccumulation appears to be related to the lipid content 

of both the coral and the algae (Kennedy et al., 1992). Accumulation of PAHs by corals is not an impact by itself; however, 

the accumulation of a chemical contaminant in an organism increases the likelihood of adverse effects. Solbakken et al. 

(1984) demonstrated that both phenanthrene and naphthalene were accumulated by the brain coral (Diploria strigosa) 

and green cactus coral (Madracis decatis), and that the lower molecular weight naphthalene was eliminated at a higher 

rate than phenanthrene (Solbakken et al., 1984). Fluoranthene and pyrene can be toxic to adult corals, particularly in the 

presence of increased ultraviolet radiation (i.e., phototoxicity; Peachey and Crosby, 1996; Guzman-Martinez et al., 2007). 

Polychlorinated biphenyls (PCBs)

PCBs are a class of synthetic organic compounds that have been used in a wide range of applications ranging from electrical transformers and capacitors, to hydraulic and heat transfer fluids, to pesticides and paints. Although no longer manufactured in the U.S., environmental contamination by PCBs is still a potential problem in many environmental systems due 

to PCBs’ environmental persistence and tendency to bioaccumulate. In some cases, use of equipment containing PCBs 

(e.g., railroad locomotive transformers) is still permitted (CFR, 1998). The structure of PCBs includes a biphenyl ring 

structure (two benzene rings with a carbon to carbon bond) and chlorine atoms, the latter of which varies in both number 

and location on the rings. There are 209 PCB congeners (structures) possible. 

64 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

65 Contaminants 

Environmental Effects of PCBs 

Exposure to PCBs has been linked to reduced growth, reproductive impairment and vertebral abnormalities in fish 

(EPA,1997). Solbakken et al. (1984) quantified the bioconcentration of radiolabeled hexaPCB (2,4,5,2’,4’,5’-hexachlorobiphenyl) in coral. The PCB was rapidly accumulated in brain coral and green cactus coral. However, depuration proceeded 

at a slow rate; after 275 days nearly 33% of the original radioactivity from the PCB remained in the coral, suggesting that 

PCBs are quite persistent in coral tissues. 

Organochlorine Pesticides

For this study, a total of 31 organochlorine pesticides were analyzed in the sediment and coral samples (Table 3. 1). From 

the 1950s to the early 1970s, a series of chlorine containing hydrocarbon insecticides were used to control mosquitoes 

and agricultural pests. One of the best known of these pesticides used during this time period was dichlorodiphenyltrichloroethane, more commonly known as DDT. Before DDT was banned in 1972, an estimated 1.35 billion pounds of DDT 

were applied in the U.S., the majority of which was applied to cotton crops (EPA, 2009). Organochlorine pesticides, including DDT, are of great environmental concern due to their environmental persistence, potential to bioaccumulate, and 

toxicity to non-target organisms. These concerns led to their ban in the U.S., but because of their persistence and heavy 

use in the past, residues of many organochlorine pesticides can be found in the environment, including biota. Other pesticides quantified in this study include: Hexachlorocyclohexane (HCH), chlordane, chlorobenzenes, aldrin, dieldrin, endrin, 

chlorpyrifos, mirex and endosulfans. 

Environmental Effects of Organochlorine Pesticides 

Organochlorine pesticides primarily act on biota as neurotoxins. Like PCBs, DDT has also been shown to be endocrine 

disruptors. DDT and its metabolite DDE have been specifically linked to eggshell thinning in birds, particularly raptors. 

A number of organochlorine pesticides are also toxic to aquatic life including crayfish, shrimp and some species of fish. 

Butyltins

Butyltins (mono-, di-,tri- and tetrabutyltins) have a range of uses from biocides to catalysts to glass coatings. In the 1950s, 

tributyltin, or TBT, was first shown to have properties as an effective biocide (Bennett, 1996). Beginning in the late 1960s, 

TBT was incorporated into a very effective antifoulant paint system, quickly becoming one of the most effective paints ever 

used on boat hulls (Birchenough et al., 2002). TBT was utilized in a polymer boat paint system that released the biocide 

at a constant, slow rate, which effectively controlled hull fouling organisms such as barnacles, mussels, weeds and algae 

(Bennett, 1996). In the aquatic environment, TBT experiences both photodegradation and microbial metabolism (Bennett, 

1996). The breakdown process involves sequential debutylization resulting in dibutyltin, monobutyltin and finally inorganic 

tin (Batley, 1996). The half-life of TBT (i.e., the amount of time needed to convert half of the TBT to dibutyltin) in natural 

waters has been experimentally determined to be on the order of days; further degradation to monobutyltin takes approximately a month (Batley, 1996). Experiments with aerobic sediments have shown that the half-life of TBT is similar to that 

measured in the water column. In anoxic sediments, however, the half-life of TBT is considerably longer, on the order of 

two to four years (Batley, 1996). 

Environmental Effects of TBT 

TBT in the aquatic environment has been associated with endocrine disruption, specifically an imposex condition in marine gastropod mollusks. Beginning in 1989 in the U.S., the use of TBT as an antifouling agent was banned on vessels 

smaller than 25 m in length (Gibbs and Bryan, 1996). Negri et al. (2002) investigated the effects of TBT in sediments 

from a shipwreck, on the coral Acropora microphthalma from the Great Barrier Reef in Australia. Sediments originally 

contained approximately 160 μg/g TBT. Even when diluted to 5% of the original TBT concentration, successful settlement 

of coral larvae in the laboratory was inhibited. 

mAjoR And tRACe elements 

A total of 16 trace and major elements were measured in sediments, and 14 in coral tissues for this project (Table 3.1). 

Most of these elements are metals, however, antimony, arsenic and silicon are metalloids; selenium is a nonmetal. All occur naturally to some extent in the environment. Aluminum, iron and silicon are major crustal elements (i.e. components 

of the earth’s crust). Some trace and major elements in the appropriate concentrations are biologically essential. As their 

name implies, trace elements such as chromium, cadmium, lead and nickel occur at lower concentrations in crustal material than aluminum, iron and silicon; however, mining and manufacturing processes along with the use and disposal of 

products containing trace elements can result in elevated concentrations in the environment. 

Environmental Effects of Trace Elements 

A number of trace elements are toxic at low concentrations. Cadmium, used in metal plating, solders and batteries, has 

been shown to impair development and reproduction in several invertebrate species, and impedes the ability to osmoregulate in herring larvae (USDHHS, 1999; Eisler, 1985). Mercury is volatile and can enter the atmosphere through processes including mining, manufacturing, combustion of coal and volcanic eruptions, then returning to earth as atmospheric 

deposition. Effects of mercury on copepods include reduced growth and reproductive rates (Eisler, 1987). Chromium can 

enter the environment through oil and coal combustion, and various industrial waste streams (textiles and leather produc­
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

66 Contaminants 

tion, electroplating). Chromium has been shown to reduce survival and fecundity in the cladoceran Daphnia magna, and 

reduced growth in fingerling chinook salmon (Oncorhynchus tshawytscha; Eisler 1986). Copper has a number of uses 

such as in antifouling paints, wood preservatives, heat exchangers in power plants, electrical wires, coinage and agriculture. Although a biologically essential element, elevated levels of copper can impact aquatic organisms, including adverse 

effects on reproduction and development in mysid shrimp (Eisler, 1998). In corals, Reichelt-Brushett and Harrison (2005) 

found that a copper concentration of 20 μg/L significantly reduced fertilization success in lesser star coral (Goniastrea 

aspera). At copper concentrations at or above 75 μg/L, fertilization success was reduced to 1% or less. Fertilization success was also significantly reduced in the stagehorn coral (Acropora longicyathus) at 24 μg/L, a similar concentration level 

to when effects were observed in lesser star coral. 

Additional Data 

Sediment samples were also analyzed for total organic carbon (TOC) and grain size. These two pieces of ancillary data 

are important for assessing the potential for accumulation of contaminants in sediments. In general, for freshwater, estuarine and coastal waters, a positive correlation exists between sediment TOC and chemical contaminants, particularly 

organic contaminants (Shine and Wallace, 2000; Hassett et al., 1980). Sediment grain size is also an important characteristic that can influence contaminant concentrations. Organic contaminants, as well as a number of metals bind to 

the smaller silt and clay grain size fractions of sediments, due to the larger surface areas of these fractions. The charge 

characteristics of clays (small size fraction) lend themselves to preferential attachment of trace and major elements. 

The bacteria Clostridium perfringens, often used as an indicator of sewage, was analyzed in the sediments collected. This 

anaerobic, gram positive staining rod-shaped bacteria frequently occurs in the intestines of humans as well as in domestic 

and wild animals. 

Coral tissues were analyzed for lipid content. Tissues with higher lipid content have the potential to sequester more lipophilic compounds, such as organic contaminants. 

methods 

Sampling Design

In order to assess the overall contaminant 

condition of the ecosystem, and to be able 

to make geographically explicit conclusions 

about how pollutants vary spatially, a stratified random sampling design was utilized. 

Using this approach, all areas had an equal 

chance of being selected as a sampling site. 

Sediment strata were constructed from existing benthic habitat maps and included all 

non-hard bottom sediments. Six geographic 

strata were initially articulated for sediment 

sampling: three within the bay (North Bay, 

Central Bay, South Bay) and three immediately offshore from the bay (west offshore, 

central offshore, east offshore). In each of 

these six strata, five sites were randomly 

selected (Figure 3.1). If a site could not be 

sampled (e.g., if the site was inaccessible) a 

pre-selected randomly determined alternate 

site from within that strata was sampled. 

Additionally, three targeted sediment sites 

were selected in the watershed. These sites 

included: a site as close to the mouth of 

the Rio Loco as could be safely sampled, a 

site on the main stem of the Rio Loco and a 

site on the agricultural canal that drains the 

Lajas Valley to the west of the Rio Loco (Figure 3.1). These sites could not be randomly 

selected due to site access considerations; 

the exact location of these sites was determined by where stream access was logistically possible. Thirty-three sediment sites 

were sampled in June 2009. In order to better understand potential watershed sources 

Figure 3.1. Sediment sampling sites from June, 2009. Sites were selected in six 

geographic strata (yellow polygons) in a stratified random design with the exception 

of the three watershed sites which were targeted. 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

67 Contaminants 

of contaminants, additional stream samples 

were collected in February 2013 (Appendix 

B, Figure B.14). 

Coral sampling strata had the same geographic boundaries as the three offshore 

strata as the sediment sampling, but for the 

hardbottom areas. Live coral is not present 

in sufficient quantities within the bay in order to sample the bay. Within each stratum, 

five sites were randomly selected from hard 

bottom habitat areas using existing habitat maps (Figure 3.2). If a site could not be 

sampled (e.g., due to a lack of coral, or the 

site being inaccessible) a pre-selected randomly determined alternate site from within 

that strata was sampled. Mustard hill coral 

(Porites astreoides) was chosen for this 

study as it is a common species of coral 

in the Caribbean (Humann and DeLoach, 

2002), and is easy to find on hard bottom 

portions of the study area. Colonies of mustard hill coral are generally massive but are 

often found as encrusting forms, particularly 

in shallow, surging waters (Veron, 2000). 

Previous studies (Pait et al., 2009; Bauer 

and Kendall, 2010; Whitall et al., 2011) also quantified contaminants in P. astreoides in other systems in Puerto Rico, 

which allows for comparison across the region. Coral tissue was collected from 15 sites in June 2009. 

Materials and Methods 

Sediment samples were collected using standard NOAA NS&T Program protocols (Lauenstein and Cantillo, 1998). Briefly, a Ponar sediment grab was deployed to collect the sediment samples. Rocks, large coral or shell fragments or bits of 

seagrass were removed. If an individual grab did not result in 200-300 g of sediment, a second grab was collected and 

composited with material from the first grab. If enough sediment had not been collected after three deployments of the 

grab, the site was abandoned and the boat moved on to an alternate, randomly preselected site. 

To avoid contamination of samples by equipment and cross contamination between samples, visible sediment was removed from the grab with a brush, then all sampling equipment was rinsed with acetone followed by site water just prior 

to use. Field personnel handling the samples wore disposable nitrile gloves. The top 3 cm of sediment were collected from 

the sediment grab using a Kynar-coated sediment scoop. Sediments were placed into a certified clean (IChem®) 250 ml 

labeled jar, capped and then placed on ice in a cooler. Sediments for grain size analysis were placed in a Whirl-Pak® bag, 

sealed and placed on ice in a cooler. After returning from the field each day, sediment samples were frozen (-15°C) and 

the Whirl-Pak® bags used for grain size analysis were refrigerated (4°C), to avoid altering the grain size structure of the 

sediment that could occur during freezing. Targeted watershed sites were sampled in the same fashion, with the exception that samples were taken by hand (i.e., sediment was scooped into jars) rather than using a dredge. 

The coral samples were taken by NOAA SCUBA divers using a hammer and titanium punch. Titanium was used as it was 

not a target trace element for this project. Prior to each use, the punch was rinsed with acetone and site water to minimize 

cross-contamination between sites. 

Divers collecting the coral samples also wore disposable nitrile gloves. The diver hammered the titanium punch into the 

coral head which produced a coral core with a diameter of approximately 1.5 cm and a similar core length. Approximately 

20 cores were taken at each site and placed underwater in an IChem® certified clean 250 ml jar and then capped. The 

jar was brought to the surface, drained of water and placed on ice. At the end of each day, the samples were placed in a 

freezer (-15°C). At the end of the mission, samples were shipped overnight to the laboratory for analysis. 

Field researchers measured a suite of water parameters (dissolved oxygen, temperature, salinity and conductivity) at 

each coral site using a YSI® salinity/conductivity/temperature meter. The instrument probe was submerged to a depth of 

approximately 0.5 m. Strong offshore currents prevented the measurement of bottom water parameters. Unfortunately, 

due to equipment failure during the sampling mission, YSI data are not available for the sediment sites. 

PAHs were analyzed in the laboratory using gas chromatography/mass spectrometry in the selected ion monitoring mode 

(Kimbrough et al., 2006). Selected chlorinated organics (PCBs and pesticides) were analyzed using gas chromatography/ 

electron capture detection (Kimbrough et al., 2006). Butyltins were analyzed using gas chromatography/flame photometric detection (Kimbrough et al., 2006). 

Figure 3.2. Coral (mustard hill coral, Porites astreoides) sampling sites from June, 

2009. Sites were selected in three geographic strata (yellow polygons) in a stratified 

random design. 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Contaminants 

Silver, cadmium, copper, lead, antimony and tin were analyzed using inductively coupled plasma - mass spectrometry. 

Aluminum, arsenic, chromium, iron, manganese, nickel, silicon and zinc were analyzed using inductively coupled plasma 

- optical emission spectrometry. Mercury was analyzed using cold vapor - atomic absorption spectrometry. Selenium 

was analyzed using atomic fluorescence spectrometry (Kimbrough and Lauenstein et al., 2006). For each element, total 

elemental concentration (i.e. sum of all oxidation states) was measured. 

TOC was quantified via high temperature combustion and subsequent quantification of the CO2 produced (McDonald et 

al., 2006). Grain size analysis was carried out using a series of sieving and settling techniques (McDonald et al., 2006). 

To assess the presence of viable C. perfringens, sediment extracts were plated on growth medium and the number of 

colonies that developed were counted. 

stAtistiCAl AnAlYsis 

All contaminant data were analyzed using JMP® statistical software. The data were first tested for normality using the 

Shapiro-Wilk test. The data were not normally distributed. A non-parametric multiple comparisons test (Dunn Method 

for Joint Ranking, α=0.05) was used to evaluate differences between strata. The three watershed sites were targeted 

rather than randomly selected; these values were included in the summary statistics for the entire study area, but were 

not included in the analysis of strata. Spearman Rank correlations (α=0.05) were examined to evaluate the relationships 

between variables. 

Providing Context for Results

In addition to comparing contamination Table 3. 2. Sediment Quality Guidelines (Long and Morgan, 1990). 

results between strata, there are several 

other ways to evaluate the relative level of 

contamination of Guánica Bay and the surrounding reef ecosystems. First, and most 

simply, these findings can be compared to 

the contaminant concentrations in other 

studies in Puerto Rico. Second, when the 

values for Guánica Bay were found to be 

high compared to the rest of the region, the 

findings can be placed in a national context 

by comparing the results to a national dataset, such as NOAA’s NS&T Program, which 

includes sediment chemistry data from over 

300 coastal sites throughout the U.S. Finally, the degree of sediment contamination in 

Guánica Bay can be assessed using NOAA’s numerical sediment quality guidelines 

(SQG) known as ERL (effects range-low) 

and ERM (effects range-median) developed 

by Long and Morgan (1990) and Long et al. 

Contaminant effects Range-low effects Range-median 

Total PAHs (ng/g) 4,022 44,792 

Total PCBs (ng/g) 22.7 180 

Total DDT (ng/g) 1.58 46.1 

Ag (μg/g) 1 3.7 

As (μg/g) 8.2 70 

Cd (μg/g) 1.2 9.6 

Cr (μg/g) 81 370 

Cu (μg/g) 34 270 

Hg (μg/g) 0.15 0.71 

Ni (μg/g) 20.9 51.6 

Pb (μg/g) 46.7 NA 

Zn (μg/g) 150 410 

(1995). The SQG value was not defined for all analytes; existing values are presented in Table 3. 2. These guidelines are 

statistically derived levels of contamination above which toxic effects would be expected to be observed in benthic organisms with at least a 50% frequency (ERM), and below which effects were rarely (<10 %) expected (ERL). Unfortunately, 

threshold values are not available for coral body burdens; coral tissue concentrations were compared to other studies in 

the region. 

68 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Contaminants 

ContAminAnt Results And disCussion 

Organics 

PAHs in Sediments 

Concentrations of total PAHs (sum of 58 

PAHs measured in this study) in sediments 

ranged from 0.6 ng/g to 4,664 ng/g (Figure 

3.3), with a mean of 614.8 ng/g (Table 3.3). 

The PAH concentrations measured in this 

study are within the range of PAH values 

measured in sediments in other locations 

in Puerto Rico (Table 3.4). When comparing measured concentrations to published 

sediment quality guidelines, total PAHs exceeded the ERL at three sites in the bay. 

No sites exceeded the ERM. The three sites 

exceeding the ERL are in the Central Bay 

and North Bay strata. There are a number 

of active boat docks near these sites which 

may be a source of PAHs. Concentrations of 

total PAHs in the North Bay and Central Bay 

are significantly greater than concentrations 

in the central offshore and eastern offshore 

strata (Dunn Method, α=0.05). The ratios 

of phenanthrene-to-anthracene (P/A) and 

fluoranthene-to-pyrene (F/P) have been 

used as a screening tool to assess the relative contributions of pyrogenic (combustionrelated) versus petrogenic (uncombusted) 

sources of PAHs (Budzinski et al., 1997). 

Higher levels of uncombusted PAHs would 

be more indicative of the presence of spilled 

fuels such as gasoline, or oil. P/A ratios 

less than 10 are more indicative of pyrogenic sources; F/P ratios greater than one 

are also thought to be associated with pyrogenic sources. F/P ratios are close to or 

greater than one at the majority of sites (20 

of 33) suggesting that, in the study area as a whole, uncombusted sources are more important than combusted sources 

of PAHs. There was a well documented oil spill in the area in August of 2007 (Coast Guard News, 2007), which may be a 

source of some of these PAHs and in conjunction with PAHs from small boat traffic, could explain these patterns. 

Table 3. 3. Summary statistics for organic contaminants quantified in sediments in Guánica Bay. Units are ng/g (butyltins are expressed 

as ng Sn/g). 

Figure 3.3. Concentrations of total PAHs in sediments. Red indicates an exceedance 

of the ERL. 

Analyte mean median min max stdev 

Total PAHs 614.829 74.000 0.637 4663.143 1272.227 

Total DDTs 10.132 0.423 0.000 69.246 18.714 

Total PCBs 336.068 24.345 0.113 3059.902 661.813 

Total HCH 0.056 0.042 0.000 0.253 0.057 

Total Chlordane 0.491 0.047 0.000 7.393 1.335 

Monobutyltin 0.160 0.000 0.000 0.930 0.232 

Dibutyltin 0.135 0.143 0.000 0.790 0.163 

Tributyltin 0.079 0.000 0.000 1.190 0.261 

69 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Contaminants 

Table 3.4. Comparison of Guánica sediment findings (mean and maxima) with three other study sites in Puerto Rico: southwest Puerto 

Rico (SW PR; Pait et al., 2007), Jobos Bay (Whitall et al., 2011) and Vieques (Pait et al., 2010). Italics denote instances where Guánica 

was higher than other studies. All raw data from these studies is also available on the NOAA NS&T data server (http://egisws02.nos.

noaa.gov/nsandt/). Unless otherwise noted, units of organic pollutants are ng/g; units of trace elements are ng/g. 

mean max 

Guánica sW PR jobos Vieques Guánica sW PR jobos Vieques 

Total DDT 10.13 2.10 0.54 23.61 69.25 46.93 3.28 1,273.66 

Total PAHs 614.8 80.6 1,061.7 52.3 4,663.1 911.2 14,249.9 370.3 

Total PCBs 336.07 75.31 2.09 0.45 3,059.90 1,970.28 19.24 4.85 

Total HCH 0.056 0.043 0.047 0.070 0.253 0.685 0.698 1.807 

Total Chlordane 0.49 0.15 0.21 0.04 7.39 2.54 2.21 0.67 

TBT (ng Sn/g) 0.16 0.01 0.56 0.04 0.93 0.29 10.91 1.23 

DBT (ng Sn/g) 0.14 0.16 0.45 0.26 0.79 0.55 3.78 1.27 

MBT (ng Sn/g) 0.08 0.39 0.66 0.29 1.19 1.54 6.60 2.67 

Ag 0.019 0.002 0.118 0.103 0.174 0.081 0.219 0.575 

Al 23,880 5,983 39,138 35,532 62,800 66,600 73,700 118,000 

As 4.77 1.73 12.59 4.37 12.80 10.30 28.10 15.40 

Cd 0.017 0.009 0.008 0.133 0.108 0.223 0.174 1.920 

Cr 286.46 31.17 18.20 22.45 1,930.00 440.00 29.80 178.00 

Cu 29.18 5.21 33.83 25.91 102.00 80.60 73.70 103.00 

Fe 27431 5,210 26,565 17611 94,000 58,900 50,500 50700 

Hg 0.039 0.004 0.043 0.019 0.186 0.095 0.144 0.112 

Mn 469.63 109.40 510.56 300.91 2,020.00 774.00 1,130.00 967.00 

Ni 228.71 26.56 10.96 7.80 709.00 442.00 31.00 38.30 

Pb 6.08 1.93 7.15 5.42 31.90 13.70 16.70 17.60 

Sb 0.14 0.09 0.22 0.23 0.43 0.33 0.59 1.19 

Se 0.15 0.17 0.33 0.26 0.51 0.43 1.56 1.20 

Si 84,726 18,885 127,849 118,243 220,000 187,000 235,000 451,000 

Sn 0.83 0.21 1.13 0.66 3.93 2.93 2.74 17.10 

Zn 46.71 7.99 54.21 34.36 153.00 90.70 117.00 130.00 

70 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Contaminants 

PAHs in Coral Tissue 

Concentrations of total PAHs in coral tissues 

ranged from 2.4 ng/g to 8.7 ng/g (Figure 

3.4) with a mean of 4.35 ng/g (Table 3.5), 

which is orders of magnitude lower than values observed in the sediments. The PAH 

concentrations measured in this study are 

within the range of PAH values measured 

in corals in other locations in Puerto Rico 

(Table 3.6), although values in this study are 

lower than what was observed farther to the 

west in La Parguera (Pait et al., 2008). No 

statistically significant differences existed 

between the strata (Dunn Method, α=0.05). 

The coral sampling site with the highest 

recorded concentration of total PAHs was 

located near the mouth of Guánica Bay at 

a concentration of 8.7 ng/g. Elevated concentrations around southwest Puerto Rico 

may be due to the high intensity recreational 

boating and storm water from urban areas 

near the coast. More research is needed to 

understand the uptake and accumulation of 

PAHs in corals in order to accurately determine sources and impacts of PAH contaminants. 

Figure 3.4. Concentrations of total PAHs in coral (Porites astreoides). 

Table 3.5. Summary statistics for organic contaminants quantified in corals in 

Guánica Bay. Units are ng/g (butyltins are expressed as ng Sn/g). 

Analyte mean median min max stdev 

Total PAHs 4.353 3.8 2.4 8.7 1.587 

Total DDT 0.055 0 0 0.28 0.099 

Total PCB 0.464 0.1299 0 3.52 0.9 

Total HCH 0.094 0 0 3.52 0.9 

Total Chlordane 0.038 0 0 0.52 0.133 

Monobutyltin 0 0 0 0 0 

Dibutyltin 0 0 0 0 0 

Tributyltin 0 0 0 0 0 

71 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Contaminants 

 

Table 3.6. Comparison of Guánica coral tissue findings (mean and maximum) with three other study sites in Puerto Rico: southwest 

Puerto Rico (SW PR; Pait et al., 2007), Jobos Bay (Whitall et al., 2011) and Vieques (Pait et al., 2010). Italics denote instances where 

Guánica was higher than other studies. All raw data from these studies is also available on the NOAA NS&T data server (http://

egisws02.nos.noaa.gov/nsandt/). Units of organic pollutants are ng/g; units of trace elements are μg/g. 

mean maximum 

Guánica sW PR jobos bay Vieques Guánica sW PR jobos bay Vieques 

Total DDT 0.06 0.08 0.04 0.13 0.28 0.62 0.60 2.26 

Total PAHs 4.353 41.91 4.58 15.00 8.700 154.00 6.40 21.50 

Total PCBs 0.464 1.016 0.120 0.229 3.518 5.390 0.623 1.711 

Total HCH 0.09 0 0 0 1.28 0 0 0.05 

Total Chlordane 0.04 0 0 0.12 0.52 0 0 0.81 

Ag 0.004 0 0 0.013 0.055 0.094 0 0.033 

Al 68.51 37.80 177.69 30.75 140.00 82.20 333.00 103.00 

As 1.42 0 1.68 0.24 2.37 0 2.44 3.42 

Cd 0.27 0 0.25 0.19 0.33 0 0.31 0.29 

Cr 0 0 0 0.18 0 0 0 1.09 

Cu 22.47 2.06 50.30 0.76 76.90 3.54 97.20 6.51 

Fe 100.73 90.80 212.13 51.20 480.00 353.00 480.00 526.00 

Hg 0 0 0 <0.001 0 0 0 0 

Mn 10.48 3.01 13.33 2.66 21.20 5.36 24.60 8.24 

Ni 4.66 1.32 3.13 0.90 11.60 2.70 6.84 8.09 

Pb 0.13 0 1.43 0.07 0.32 0.07 12.50 0.17 

Se 0.19 0.05 0.18 0.10 0.25 0.37 0.26 0.34 

Sn 0.07 0.02 0.01 0.25 0.27 0.14 0.10 0.40 

Zn 9.42 6.09 8.59 3.43 25.20 18.30 16.90 15.20 

PCBs in Sediments 

Concentrations of total PCBs (sum of 38 PCB 

congeners analyzed) in sediments ranged 

from 2.27 ng/g to 3,860 ng/g (Figure 3.5) 

with a mean of 424.6 ng/g (Table 3. 3). This 

is markedly higher than sediment concentrations measured in other studies in Puerto Rico 

(Table 3.4). Because NOAA’s NS&T Program 

has been monitoring contaminants, including 

PCBs, in the environment since 1986, the high 

concentrations observed in this study can be 

put in national and historical context. A number of individual PCB congener concentrations 

measured in the Guánica Bay area (including 

two sites in the bay measured as part of Pait 

et al., 2008) were in the top 10% of all measured sediment concentrations (nationwide, 

since 1986). Additionally, for some additional 

congeners the concentrations measured in 

this study were among the top ten highest individual values ever measured by NS&T (Table 

3.7). PCB146, PCB194 and PCB199 were especially high, with sites from Guánica Bay representing seven of the highest 10 values ever 

measured for those congeners. It is clear that 

sediment PCB concentrations in Guánica Bay 

are very high, not only for the region, for the 

nation as well. PCBs are one of the few analytes where there is strong evidence of transport 

from the bay to the offshore area, with higher

 offshore concentrations to the west, as would Figure 3.5. Concentrations of total PCBs in sediments. Red indicates an be expected with the predominant longshore exceedance of the ERL. Red stars indicate exceedance of ERM. 

72 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Contaminants 

current direction. Statistically, total PCB concentrations in the Central Bay are greater than central offshore and eastern 

offshore, and the North Bay concentrations are greater than the eastern offshore stratum (Dunn Method, α=0.05). 

Table 3.7. Comparison of individual PCB congeners from Guánica Bay with national historic sediment values from NOAA’s NS&T program. All NS&T sediment data for each congener were ranked and the frequency of Guánica data points occurring the top 10% and 

top 10 individual values is presented here. Also shown are the highest ever reported value for each congener. All raw data is available 

on the NOAA NS&T data server (http://egisws02.nos.noaa.gov/nsandt/). 

Analyte # in top 10 # in top 10% highest Value nationwide highest Value location 

PCB146 7 23 26.42 Guánica Bay 

PCB199 7 13 20.95 Guánica Bay 

PCB194 7 19 35.27 Guánica Bay 

PCB183 5 22 27.61 Guánica Bay 

PCB151 5 19 39.38 Guánica Bay 

PCB156_171_202 4 17 22.93 Guánica Bay 

PCB158 4 17 21.8 San Diego Bay 

PCB174 3 15 38.02 Guánica Bay 

PCB99 3 13 135.325 Lake Michigan 

PCB29 2 14 27.82 Lake Erie 

PCB49 2 22 795.859 Lake Michigan 

PCB149_123 2 14 120 San Diego Bay 

PCB31 1 22 1464.887 Lake Michigan 

PCB87_115 1 14 82.02 Lake Michigan 

PCB74_61 1 13 499.914 Lake Michigan 

PCB95 1 11 145 San Diego Bay 

PCB187 1 11 186.3 Tampa Bay 

PCB180 1 12 350 Puget Sound 

PCB52 1 8 996 Tampa Bay 

PCB153_132_168 1 6 570.9 Tampa Bay 

PCB70 0 14 585.736 Lake Michigan 

PCB56_60 0 12 474.747 Lake Michigan 

PCB45 0 8 37.589 Lake Michigan 

PCB8_5 0 15 596.22 Lake Michigan 

PCB201_173_157 0 14 13.4 San Diego Bay 

PCB195_208 0 14 260 Puget Sound 

PCB110_77 0 8 325.543 Lake Michigan 

PCB28 0 13 1118.705 Lake Michigan 

PCB18 0 13 588.921 Lake Michigan 

PCB170_190 0 12 314.63 Delaware Bay 

PCB138_160 0 10 706.4 Tampa Bay 

PCB101_90 0 6 406 Boston Harbor 

PCB118 0 8 382 Boston Harbor 

PCB66 0 7 427.551 Lake Michigan 

PCB206 0 7 612.639 St. Simon Sound (GA) 

PCB128 0 6 238.5 Tampa Bay 

PCB44 0 3 394.022 Lake Michigan 

PCB105 0 2 696.9 Tampa Bay 

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Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

74 Contaminants 

PCBs in Coral Tissues 

Concentrations of total PCBs in coral tissues 

ranged from below limits of detection to 3.52 

ng/g (Figure 3.6) with a mean of 0.464 ng/g 

(Table 3. 5), which is orders of magnitude 

lower than the concentrations measured in 

sediments. The measured mean coral concentration of total PCBs in sampled coral 

tissues is consistent with concentrations 

found in other reefs of Puerto Rico, despite 

the fact that PCBs in sediments are very 

high in Guánica compared to other systems 

in the region. Both previous studies (Pait et 

al., 2008) and coral and sediment data from 

this study suggest a possible downstream 

concentration gradient of PCBs moving 

from Guánica Bay westward, but this does 

not appear to be resulting in unusually high 

PCB uptake by corals. There were no statistically significant differences between sampling strata for PCBs in coral tissues (Dunn 

Method, α=0.05). 

There is no obvious source of PCBs in the 

watershed. Because PCBs have historically 

been used for a wide variety of applications 

(e.g. electrical applications, hydraulic fluids, 

pesticides), it may be difficult to identify the 

original source of these high levels of pollution. Figure 3.6. Concentrations of total PCBs in coral (Porites astreoides). 

DDT in Sediment 

Concentrations of total DDT (sum of parent 

compound and its degradation products, 

DDD and DDE) in sediments ranged from 

below detection limits to 69.25 ng/g (Figure 3.7), with a mean of 10.13 ng/g (Table 

3.3). These observed concentrations are 

somewhat higher than observed in other locations on the south coast of Puerto Rico, 

but are lower than the highest values measured in the region (Vieques, Puerto Rico; 

see Table 3.4). When comparing measured 

concentration to published sediment quality guidelines, total DDT exceeded the ERL 

at 15 sites, and exceeded the ERM at two 

sites. Exceedances were limited to strata within the bay, but every site within the 

bay exceeded the ERL. Statistically, total 

DDT concentrations in the Central Bay are 

greater than central offshore and eastern 

offshore, and the North Bay concentrations 

are greater than the eastern offshore stratum (Dunn Method, α=0.05). While not included in the statistical analysis, concentrations at the watershed sites were relatively 

low when compared with the bay. This is relatively unexpected as the watershed should 

have historically been a source of DDT (see 

additional discussion of watershed sites below). 

Because the measurement of total DDT is 

made up of both the parent isomers and 

degradation products, the ratio of parent Figure 3.7. Concentrations of total DDT in sediments. Red indicates an exceedance 

of the ERL. Red stars indicate exceedance of ERM. 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

75 Contaminants 

compounds to degradation products can 

provide some insight into the relative age 

or “freshness” of the DDT present. Total 

DDT concentrations containing higher ratios of the parent compound are more likely 

to be recently introduced into the environment. The sites with the highest total DDT 

concentrations were made up primarily of 

degradation products. Parent material was 

more prevalent at two sites in the watershed (WS107, WS108) and two sites offshore (CO078a and WO101a), which had 

greater than two-third parent material. The 

sites with high parent material had relatively 

low concentrations so it is possible that this 

represents areas of slow DDT degradation, 

rather than a “new” source of DDT, such as 

a leaking container or illegal use. 

DDT in Coral Tissue 

Concentrations of total DDT in coral tissues 

ranged from below detection limits to 0.28 

ng/g (Figure 3.8), with a mean of 0.06 ng/g 

(Table 3.5) which is two orders of magnitude 

lower than concentrations observed in the 

sediments. These observed concentrations 

are similar to concentrations observed in 

coral tissues in other locations on the south 

coast of Puerto Rico, but are lower than the 

highest values measured in the region (Vieques, Puerto Rico; see Table 3.6). No statistically significant differences in concentrations were observed between the three 

strata (Dunn Method, α=0.05). 

A negative correlation was found between DDT concentration in coral tissues and longitude, further suggesting that DDT 

concentrations increase from east to west (Spearman Rho = -0.6096). Futher study is needed to link near shore oceanographic current data with contaminant data to understand how these pollutants are moving in the near coastal zone. 

Despite the fact that DDT was banned in the United States in 1972, it is not surprising that it continues to be found in the 

environment. The agricultural use of banned organochlorines have been found throughout the Caribbean region until 

the late 1990s (Alegria et al., 2000). Due to the long time period required for sediment to flush out of the Guánica Bay/ 

Rio Loco watershed and the general environmental persistance of the breakdown products, DDT used in agriculture will 

continue to persist in the environment (Larsen and Santiago-Roman, 2001). Furthermore, the transport and atmospheric 

deposition of African dust in the Caribbean has been noted as a potential source of organochlorine pesticides such as 

DDT (Nipper et al., 2006). 

Figure 3.8. Concentrations of total DDT in coral (Porites astreoides). 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

76 Contaminants 

HCH in Sediments 

Sediment concentrations of total HCH 

ranged from below limits of detection to 0.25 

ng/g (Figure 3.9), with a mean of 0.06 ng/g 

(Table 3.3). This is similar to what has been 

observed in other studies in Puerto Rico 

(Table 3.4). No sediment quality guidelines 

exist for HCH. There were not statistically 

significant differences between the strata, 

although some of the higher individual values occurred offshore (Figure 3.9), in contrast to what was observed with most other 

contaminants. 

HCH in Coral Tissues 

Total HCH in coral tissues ranged from below limits of detection to 1.28 ng/g (Figure 

3.10) with a mean of 0.09 ng/g (Table 3.3). 

Coral tissue concentrations from study sites 

to the east (Jobos Bay) and west (La Parguera) did not contain any detectable HCH 

concentrations (Pait et al., 2009; Whitall et 

al., 2011). A study conducted in Vieques 

detected a mean HCH concentration of 

0.00346 ng/g in coral tissues (Pait et al., 

2010; Table 3.6). There are no statistically 

significant differences between the strata 

(Dunn Method, α=0.05). This environmentally persistent insecticide may be present in 

the system due to historical use in upland 

agriculture and transported to the reefs via 

Rio Loco discharge into Guánica Bay. 

Chlordane in Sediments 

Concentration of total chlordane ranged 

from below detection levels to 7.39 ng/g 

(Figure 3.11) with a mean of 0.49 ng/g 

(Table 3.3). This is higher than previously 

observed in other regions of Puerto Rico 

(Table 3.4). When compared with historical, 

national sediment concentrations from the 

NS&T program two chemical compounds 

that make up total chlordane (cis-nonachlor 

and oxychlordane) had two sites each in the 

top 10% of all historically measured values, 

and a third chlordane compound (heptachlor) had one site that was in the top 10 

values ever measured nationally. Overall, 

17 sites exceeded the ERL, including one 

site in the North Bay which exceeded the 

ERM. Most of the sites exceeding SQG 

were in the bay, but there were three sites 

offshore (central and western strata) which 

exceeded the ERL. This was one of only a 

few contaminants for which high concentrations were observed offshore. There are no 

statistically significant differences between 

the strata (Dunn Method, α=0.05). 

Figure 3.9. Concentrations of total HCH in sediments. 

Figure 3.10. Concentrations of total HCH in coral (Porites astreoides). 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

77 Contaminants 

Chlordane in Coral Tissues 

Chlordane was detected at low levels in 

coral samples, ranging from below levels of 

detection to 0.52 ng/g (Figure 3.12) with a 

mean total concentration of 0.04 ng/g (Table 

3.4). Chlordane isomers alpha-chlordane 

and oxychlordane were both detected in 

this study. There are no statistically significant differences between the strata (Dunn 

Method, α=0.05). Previous coral contaminant studies east and west of Guánica Bay 

did not detect chlordane in coral tissue samples (Table 3.6; Pait et al., 2009). A contaminant study of corals in Vieques, Puerto Rico 

measured a mean chlordane concentration 

of 0.12 ng/g (Table 3.6; Pait et al., 2010). 

Although restricted in 1983 and banned in 

1988, chlordane was widely used in the 

U.S. prior to the ban and is environmentally 

persistent. 

Other Pesticides in Sediments 

Other pesticides or pesticide degradation 

products that were detected in sediments 

included: aldrin, dieldrin, endrin, tetrachlorobenzene, pentachlorobenzene, hexachlorobenzene, pentachloroanisole, endosulfan 

II, endosulfan sulfate, chlorpyrifos and mire. 

Spatial distribution of these contaminants 

are shown in Figures B.1 to B.11 in Appendix 

B. There are two isomers of tetrachlorobenzene; only the 1,2,3,4-tetrachlorobenzene 

isomer was detected in this study. Endosulfan I was not detected at any sites. With 

a few exceptions (discussed below), these 

detections were at a few sites, primarily in 

the bay and watershed, and at relatively low 

concentrations. 

Endosulfan sulfate was only detected at two 

sites (one in the watershed and one in the 

North Bay), but these concentrations were 

both above the NS&T national mean (0.14 

ng/g). Chlorpyrifos was only detected at 5 

sites, but three of these sites were above 

the NS&T national mean (0.15 ng/g). Pentachloroanisole, a degradation product of 

the fungicide pentachlorophenol, was the 

most widely distributed of these compounds 

and had numerous observations above the 

NS&T national mean (0.07 ng/g). Hexachlorobenzene was also detected at a 11 of 

33 sites, including three sites (one each in 

western offshore, central offshore and Central Bay strata) which exceeded the national 

NS&T average (0.65 n/g). These pesticides 

include legacy fungicides and insecticides 

that persist in the environment despite their 

use being phased out. 

Figure 3.11. Concentrations of total chlordane in sediments. Red indicates an 

exceedance of the ERL. 

Figure 3.12. Concentrations of total chlordane in coral (Porites astreoides). 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

78 Contaminants 

Butyltins in Sediments 

Tributyltin (TBT) in sediments ranged from 

below limits of detection to 0.93 ng/g (Figure 3.13), with a mean of 0.16 ng Sn/g. TBT 

breakdown products (dibutyltin (DBT) and 

monobutyltin (MBT)) were also detected in 

similar concentrations (Table 3.3). There are 

no statistically significant differences between the strata (Dunn Method, α=0.05) for 

MBT or DBT. Concentrations of TBT in the 

Central Bay are greater than the North Bay, 

central offshore and western offshore strata. 

These concentrations are within the range 

of what was observed in southwest Puerto 

Rico and Vieques, but lower than observed 

in Jobos Bay (Table 3.4). Tetrabutyltin was 

not detected in sediments at any sites. Butyltins were not well correlated with elemental 

tin, suggesting that elemental tin originates 

from a source other than the breakdown of 

organotins. 

Butyltins in Coral Tissues 

No butyltins were detected in coral tissues 

at any site (data not shown). Butyltins have 

been previously been detected in coral tissues in other locations in the region (Pait et 

al., 2007; Pait et al., 2010). 

Figure 3.13. Concentrations of TBT in sediments. 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Contaminants 

Guánica Bay Metals

Sixteen trace and major elements were analyzed in sediments collected from Guánica 

Bay and the surrounding coastal area. A 

summary of the means and standard errors for the elements are shown in Table 

3.1. The highest mean concentrations of 

all trace and major elements are those of 

silicon (73,832 μg/g), iron (22,821 μg/g) and 

aluminum (21,101 μg/g). Aluminum, iron 

and silicon are all common elements in the 

earth’s crust, and as such it is not surprising to see higher concentrations of these 

elements relative to the other 13 trace or 

major elements. This is comparable with 

results from Vieques, Puerto Rico (Pait et 

al., 2010), which found that mean concentrations of the three highest trace or major 

elements in sediments were aluminum, iron 

and silicon, respectively. 

A discussion of six elements, arsenic, chromium, copper, mercury, nickel and zinc in 

sediments follows. Brief summaries of the 

remaining 10 elements are also provided. 

Arsenic in Sediments 

Concentrations of arsenic in the sediments 

of Guánica Bay ranged from 1.28 μg/g to 

12.80 μg/g (Figure 3.14), with a mean of 

4.77 μg/g (Table 3.8), which is within the 

range of values observed for other systems 

in Puerto Rico (Table 3.4). There were three 

sites that exceeded the ERL (8.2 μg/g). No 

sediments analyzed in this study exceeded 

the ERM for arsenic. 

The highest arsenic sediment concentration of 12.8 μg/g was found in the Central Bay at site CB011. Along with CB011, 

Central Bay sites CB013 and CB015 (10.4 and 8.35 μg/g respectively) represented the highest concentrations of arsenic 

in the bay. 

Table 3.8. Summary statistics of trace elements in sediments in Guánica Bay. 

Figure 3.14. Concentrations of arsenic in sediments. Red indicates an exceedance 

of the ERL. 

element mean median min max st dev 

Ag 0.02 0 0 0.17 0.04 

Al 23,880 7,820 613 62,800 24,689 

As 4.77 4.14 1.28 12.80 2.73 

Cd 0.02 0 0 0.11 0.03 

Cr 286.46 71.50 3.48 1,930.00 422.96 

Cu 29.18 8.98 0.89 102.00 31.72 

Fe 27,431 8,400 705 94,000 29,331 

Hg 0.04 0.02 0 0.19 0.05 

Mn 470 402 38 2,020 435 

Ni 228.71 57.70 4.88 709.00 262.90 

Pb 6.08 2.93 0.20 31.90 7.21 

Sb 0.14 0.07 0 0.43 0.16 

Se 0.15 0.11 0 0.51 0.17 

Si 84,726 30,900 2,090 220,000 88,497 

Sn 0.83 0 0 3.93 1.12 

Zn 46.71 19.70 2.21 153.00 47.26 

79 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Contaminants 

Statistically, the Central Bay had higher 

arsenic concentrations than the western 

and eastern offshore strata (Dunn Method, 

α=0.05). 

Arsenic in Coral Tissues 

Arsenic concentrations in coral tissues 

ranged from 0.91 μg/g to 2.37 μg/g (Figure 

3.15), with a mean of 1.42 μg/g (Table 3.9). 

This is similar to what has been observed 

in other systems in Puerto Rico (Table 3.6). 

There were no statistically significant differences between strata for arsenic (Dunn 

Method, α=0.05). In addition to natural 

(crustal) sources, arsenic can enter the 

coastal environment from a variety of sources including treated wood, insecticides and 

herbicides, all of which may be contributing 

to the arsenic budget of Guánica Bay. 

Table 3.9. Summary statistics of trace elements in coral tissues in Guánica Bay. 

Figure 3.15. Concentrations of arsenic in coral (Porites astreoides). 

mean median min max st dev 

Ag 0.004 0 0 0.055 0.014 

Al 68.51 50.50 24.00 140.00 37.84 

As 1.42 1.31 0.91 2.37 0.44 

Cd 0.27 0.29 0 0.33 0.08 

Cr 0 0 0 0 0 

Cu 22.47 16.00 0 76.90 20.18 

Fe 100.73 59.30 28.90 480.00 113.95 

Hg 0.002 0.002 0.001 0.004 0.001 

Mn 10.48 8.66 3.73 21.20 5.48 

Ni 4.66 4.79 0.68 11.60 2.83 

Pb 0.13 0.12 0.07 0.32 0.06 

Se 0.19 0.20 0.13 0.25 0.04 

Sn 0.07 0 0 0.27 0.10 

Zn 9.42 10.30 1.82 25.20 6.41 

80 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

81 Contaminants 

Chromium in Sediments 

The mean concentration of chromium found 

in the sediments of Guánica Bay ranged 

from 3.48 μg/g to 1930 μg/g (Figure 3.16) 

with a mean of 286.5 μg/g (Table 3.8). The 

three highest concentrations of chromium 

for this study were all found at the watershed sites with the highest concentration 

being 1,930 μg/g found at site WS108. This 

is an order of magnitude higher than what 

has been measured in other sites in Puerto 

Rico (Table 3.4). When comparing chromium data from this study with historical data 

from NOAA’s NS&T Program it is noted that 

13 sites from the bay and the watershed 

were in the top 10% of all measured sediment chromium concentrations (nationwide, 

since 1986). One sediment chromium value 

from Guánica Bay (western most watershed 

site) was among the top 10 highest individual values ever measured by NS&T. It is clear 

that sediment chromium concentrations in 

Guánica Bay are very high, not only for the 

region, for the nation as well. Sixteen of the 

33 sites analyzed for this study exceeded 

the ERL for chromium. Twelve sites met 

or exceeded the ERM of 370 μg/g with the 

highest concentration exceeding the ERM 

by a factor of five. 

Statistically, the North Bay had higher chromium concentrations than the western and 

eastern offshore strata; the Central Bay had 

higher concentrations than the eastern offshore stratum (Dunn Method, α=0.05). 

Chromium in Coral Tissues 

Chromium was not detected in any of the 

coral samples around Guánica Bay (detection limit 0.102 μg/g; data not shown). Coral samples around Jobos Bay and 

southwest Puerto Rico (Whitall et al., 2011, Pait et al., 2007) also did not detect chromium although a study in Vieques, 

an island off the eastern coast of Puerto Rico, measured a mean chromium concentration of 0.18 μg/g (Table 3.6; Pait et 

al., 2009; Pait et al., 2010). 

The apparent disconnect between extremely high sediment chromium concentrations and concentrations in coral tissues 

below limits of detection, in combination with the spatial pattern of chromium in sediments, suggests that chromium pollution is, in general, not reaching the offshore coral reef systems. More research is needed (e.g., water circulation differences between sites) in order to understand this pattern. Chromium in the environment more commonly comes from point 

sources (discussed below) rather than non-point sources. 

Figure 3.16. Concentrations of chromium in sediments. Red indicates an exceedance 

of the ERL. Red stars indicate exceedance of ERM. 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

82 Contaminants 

Copper in Sediments 

Copper concentrations in sediments ranged 

from 0.89 μg/g to 102 μg/g (Figure 3.17), 

with a mean concentration of 29.18 μg/g 

(Table 3.9), which is similar to what has 

been observed in other studies in Puerto 

Rico (Table 3.6). The three highest copper 

concentrations detected in Guánica Bay 

were all located in the North and Central 

Bay with the highest concentration being 

102 μg/g at CB012. 

Thirteen sites in Guánica Bay exceeded the 

ERL (34 μg/g). No sites exceeded the ERM. 

All of these exceedances were in the bay or 

in the watershed. 

Statistically, the North Bay had higher copper concentrations than all of the offshore 

strata; the Central Bay had higher concentrations than the central offshore stratum 

(Dunn Method, α=0.05). 

Copper in Coral Tissues 

Copper concentrations in coral tissues 

ranged from below limits of detection to 

76.9 μg/g (Figure 3.18), with a mean of 22.5 

μg/g (Table 3.9) which is within the range of 

values observed in other systems in Puerto 

Rico (Table 3.6). There were no statistically significant differences between strata 

for copper concentrations in coral tissues 

(Dunn Method, α=0.05). 

Non-point sources of copper include agricultural pesticides, anti-fouling boat paint 

and dust from automobile brake pads all of 

which may contribute to the copper budget 

of the Guánica system. 

Figure 3.17. Concentrations of copper in sediments. Red indicates an exceedance 

of the ERL. 

Figure 3.18. Concentrations of copper in coral (Porites astreoides). 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

83 Contaminants 

Mercury in Sediments 

Detected concentrations of mercury from 

Guánica Bay sediments ranged from 0.001 

μg/g to 0.186 μg/g (Figure 3.19), with a 

mean of 0.04 μg/g (Table 3.8), which is 

similar to what has been measured in other 

studies in Puerto Rico (Table 3.4). The highest concentration of mercury in sediments 

in Guánica Bay was 0.1860 μg/g at site 

CB012. The Central Bay accounted for four 

of the top five concentrations of mercury in 

the study area. 

Two sites in the Central Bay exceeded the 

ERL (0.15 μg/g). No sites exceeded the 

ERM. Statistically, the Central Bay had 

higher mercury concentrations than all of 

the offshore strata; the North Bay had higher concentrations than the eastern offshore 

stratum (Dunn Method, α=0.05). 

Mercury in Coral Tissues 

Mercury concentrations in coral tissues 

ranged from below 0.001 to 0.004 μg/g (Figure 3.20), with a mean of 0.002 μg/g (Table 3.9), which is similar to what has been 

measured at other locations in Puerto Rico 

(Table 3.6). There were not statistically significant differences between strata for mercury concentrations in coral tissue (Dunn 

Method, α=0.05). Atmospheric deposition 

may be an important non-point source of Hg 

in this system. 

of the ERL.

Figure 3.19. Concentrations of mercury in sediments. Red indicates an exceedance 

Figure 3.20. Concentrations of mercury in coral (Porites astreoides). 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

84 Contaminants 

Nickel in Sediments 

Concentrations of nickel detected in the 

sediments of Guánica Bay ranged from 

4.88 to 709 μg/g (Figure 3.21), with a mean 

of 228.71 μg/g (Table 3.8), which is an order 

of magnitude higher than nickel sediment 

values observed elsewhere in the region 

(Table 3.4). In order to put this in a national 

and historical context, these values were 

compared with NOAA NS&T sediment data. 

Including two sites in Guánica Bay from a 

previous study (Pait et al., 2007), 19 sites 

from the bay and the watershed were in the 

top 10% of all measured sediment nickel 

concentrations (nationwide, since 1986). 

The 14 highest individual values ever measured by NS&T were from Guánica Bay. 

It is clear that sediment nickel concentrations in Guánica Bay are very high, not only 

for the region, for the nation as well. The 

two highest concentrations of nickel in this 

study were detected in the sediments of 

the watershed at sites WS107 and WS108 

(708 and 709 μg/g respectively). The North 

Bay had the highest nickel concentrations 

for non-watershed sites in the study area 

with four of the top five highest detections. 

Statistically, the North Bay had higher nickel concentrations than all of the offshore 

strata; the Central Bay had higher concentrations than the central offshore stratum 

(Dunn Method, α=0.05). 

Seventeen of 33 sites in this study exceeded 

the ERM (51.6 μg/g) and an additional two 

sites exceeded the ERL (20.9 μg/g), meaning that almost 60% of the sites samples in 

this region have the possibility of sediment 

toxicity due to nickel. These exceedances 

were primarily in the bay and watershed, although one site in the central offshore stratum exceeded the ERM. 

Statistically, the North Bay had higher nickel 

concentrations than the western and eastern offshore strata; the Central Bay had 

higher concentrations than the eastern offshore stratum (Dunn Method, α=0.05). 

Nickel in Coral Tissues 

Concentrations of nickel in coral tissues 

ranged from 0.68 μg/g to 11.6 μg/g (Figure 

3.22), with a mean of 4.66 μg/g (Table 3.9), 

which is an order of magnitude higher than 

observed in coral tissues in other studies 

in Puerto Rico (Table 3.6). There were no 

statistically significant differences between 

strata (Dunn Method, α=0.05). Levels of 

nickel observed in coral tissues, in combination with the observed high sediment 

nickel concentrations, suggests that the 

nickel pollution coming from the bay (via the 

watershed) is reaching the coral reef ecosystem offshore and being incorporated into 

the tissues above levels that would be assoFigure 3.21. Concentrations of nickel in sediments. Red indicates an exceedance 

of the ERL. Red stars indicate exceedance of ERM. 

Figure 3.22. Concentrations of nickel in coral (mustard hill coral). 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

85 Contaminants 

ciated with normal crustal erosion. Potential 

point sources of nickel are discussed later 

in the chapter. It is not clear what the likely 

physiological impact elevated nickel might 

have on corals; more research is needed to 

determine potential thresholds above which 

organismal harm is likely. 

Zinc in Sediments 

Detected concentrations of zinc in the sediments of Guánica Bay ranged from 2.21 

μg/g to 153 μg/g (Figure 3.23), with a mean 

concentration of 46.71 μg/g (Table 3.8), 

which is slightly higher than other observed 

values for the region (Table 3.4). Site 

WS108 (153 μg/g) exceeded the ERL (150 

μg/g). All other sites sampled for zinc in this 

study were below established guidelines. 

Two of the five highest concentrations of 

zinc were found at the watershed sites 

WS108 (153 μg/g) and WS106 (108 μg/g). 

The remaining three were found at CB012 

(117 μg/g), NB003 (113 μg/g), and CB015 

(104 μg/g). Statistically, the North Bay had 

higher zinc concentrations than any of the 

offshore strata; the Central Bay had higher 

concentrations than the central and western 

offshore strata (Dunn Method, α=0.05). 

Zinc in Coral Tissues 

Zinc concentrations in coral tissues ranged 

from 1.82 μg/g to 25.2 μg/g (Figure 3.24), 

with a mean of 9.42 μg/g (Table 3.9). This 

is similar to what has been observed in 

other sites in the region (Table 3.6). There 

were no statistically significant differences between strata for zinc (Dunn Method, 

α=0.05). Automobiles (i.e., tire dust) may be 

an important non-point source of zinc to this 

system (Councell et al., 2004). 

Figure 3.23. Concentrations of zinc in sediments. Red indicates an exceedance of 

the ERL. 

Figure 3.24. Concentrations of zinc in coral (Porites astreoides). 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

86 Contaminants 

Other Trace and Major Elements

Ten other trace and major elements were 

analyzed as part of this study in Guánica 

Bay. Some of the results are briefly summarized below. 

Aluminum 

The highest concentration of aluminum detected in this study is from the North Bay site 

NB003 (62,800 μg/g, Figure 3.25), and the 

mean was 23,880 μg/g (Table 3.8), which is 

similar to what has been observed in other 

sites in the region (Table 3.4). Statistically, 

the North Bay had higher aluminum concentrations than any of the offshore strata 

(Dunn Method, α=0.05). 

Aluminum in Coral Tissues 

Aluminum was detected in coral tissues at 

values orders of magnitude lower than observed in the sediments (Figure 3.26), with 

a mean of 68.51 μg/g (Table 3.9) and at 

similar levels to what has been observed 

elsewhere in the region (Table 3.6). There 

are no statistically significant differences 

between strata for aluminum (Dunn Method, α=0.05). 

Figure 3.25. Concentrations of aluminum in sediments. 

Figure 3.26. Concentrations of aluminum in coral (mustard hill coral). 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

87 Contaminants 

Antimony in Sediments 

Concentration of antimony in Guánica Bay 

sediments is ranged from below limits of 

detection to 0.433 μg/g (Figure 3.27), with 

a mean of 0.143 μg/g (Table 3.8), which is 

similar to what has been observed at other 

sites in the region (Table 3.4). The highest 

concentration of antimony detected is 0.433 

μg/g at the North Bay site NB005. Statistically, the North Bay had higher antimony 

concentrations than any of the offshore 

strata and the South Bay stratum (Dunn 

Method, α=0.05). 

Antimony in Coral Tissues 

Antimony was not measured in coral tissues. 

Cadmium in Sediments 

Concentrations of cadmium in sediments 

from Guánica Bay ranged from below detection limits to 0.108 μg/g (Figure 3.28), 

with a mean of 0.017 μg/g (Table 3.8), 

which is within the range of values observed within the region (Table 3.4). No 

Guánica Bay sediment sites exceeded any 

thresholds or guidelines for cadmium. The 

highest observed concentration was found 

at watershed site WS106. The three watershed sites represented three of the top 

four detected concentrations of cadmium in 

Guánica Bay. There are no significant differences between strata for cadmium (Dunn 

Method, α=0.05). 

Figure 3.27. Concentrations of antimony in sediments. 

Figure 3.28. Concentrations of cadmium in sediments. 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

88 Contaminants 

Cadmium in Coral Tissues 

Cadmium concentrations in coral tissues 

ranged from below limits of detection to 

0.33 μg/g (Figure 3.29), with a mean of 

0.269 μg/g (Table 3.9), which is similar to 

what has been observed in other studies in 

the region (Table 3.6). There were no statistically significant differences between strata 

for cadmium in coral tissues (Dunn Method, 

α=0.05). 

Iron in Sediments 

The highest concentration of iron detected in this study is from the watershed site 

WS108 (62,800 μg/g, Figure 3.30), and the 

mean was 27,431 μg/g (Table 3.8) which is 

on the high end of what has been observed 

in other sites in the region (Table 3. 4), but 

not unusually high compared to historical 

NS&T national data. The three watershed 

sites represented three of the top five detections of iron for this study. Statistically, 

the North Bay had higher iron concentrations than any of the offshore strata (Dunn 

Method, α=0.05). 

Figure 3.29. Concentrations of cadmium in coral (mustard hill coral). 

Figure 3.30. Concentrations of iron in sediments. 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

89 Contaminants 

Iron in Coral Tissues 

Iron was detected in coral tissues at values 

orders of magnitude lower than observed in 

the sediments (Figure 3.31), with a mean of 

100.73 μg/g (Table 3.9) and at similar levels to what has been observed elsewhere in 

the region (Table 3.6). There are no statistically significant differences between strata 

for iron (Dunn Method, α=0.05). 

Lead in Sediments 

The highest concentration of lead detected 

in the sediments of Guánica Bay is 31.9 μg/g 

found at the Central Bay site CB012 (Figure 3.32). The mean concentration of lead 

was 6.08 μg/g (Table 3.8), which is within 

the range of values reported for the region 

(Table 3.4). The Central Bay accounted for 

the top three lead concentrations detected 

in this study. No sediment sites from Guánica Bay exceeded any thresholds or guidelines for lead. Statistically, the Central Bay 

had higher lead concentrations than any of 

the offshore strata, while the North Bay had 

higher concentrations than the eastern offshore stratum (Dunn Method, α=0.05). 

Figure 3.31. Concentrations of iron in coral (mustard hill coral). 

Figure 3.32. Concentrations of lead in sediments. 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

90 Contaminants 

Lead in Coral Tissues 

Lead was detected in coral tissues at values 

orders of magnitude lower than observed in 

the sediments (Figure 3.33, Table 3.9), and 

at similar levels to what has been observed 

elsewhere in the region (Table 3.6). There 

are no statistically significant differences 

between strata for lead (Dunn Method, 

α=0.05). 

Manganese in Sediments 

The highest concentration of manganese 

detected was 2,020 μg/g at the watershed 

site WS108 (Figure 3.34). The mean concentration of manganese in the sediments 

of Guánica Bay is 469.63 μg/g (Table 3.8) 

which is higher than observed at other sites 

in the region (Table 3.4) and slightly higher than the NS&T national mean (425.82 

μg/g). The three watershed sites represented three of the top five detections of manganese for this study. Statistically, the Central 

Bay had higher manganese concentrations 

than any of the offshore strata (Dunn Method, α=0.05). 

Figure 3.33. Concentrations of lead in coral (mustard hill coral). 

Figure 3.34. Concentrations of manganese in sediments. 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

91 Contaminants 

Manganese in Coral Tissues 

Manganese was detected in coral tissues 

at values orders of magnitude lower than 

observed in the sediments (Figure 3.35), 

with a mean of 10.48 μg/g (Table 3.9) and 

at similar levels to what has been observed 

elsewhere in the region (Table 3.6). There 

are no statistically significant differences 

between strata for manganese (Dunn Method, α=0.05). 

Selenium in Sediments 

The highest concentration of selenium detected in sediments from Guánica Bay is 

0.512 μg/g at the Central Bay site CB012 

(Figure 3.36). The mean concentration of 

selenium is 0.154 μg/g (Table 3.8), which 

is similar to what has been observed by 

other sites in the region (Table 3.4). Selenium concentrations are higher in the north 

stratum than the eastern offshore stratum 

(Dunn Method, α=0.05). 

Figure 3.35. Concentrations of manganese in coral (mustard hill coral). 

Figure 3.36. Concentrations of selenium in sediments. 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

92 Contaminants 

Selenium in Coral Tissues 

Selenium was detected in coral tissues at 

values orders of magnitude lower than observed in the sediments (Figure 3.37), with 

a mean of 0.19 μg/g (Table 3.9), which is 

similar to levels that have been observed 

elsewhere in the region (Table 3.6). There 

are no statistically significant differences 

between strata for selenium (Dunn Method, 

α=0.05). 

Silicon in Sediments 

The highest concentration of silicon detected is 220,000 μg/g at North Bay site NB05 

(Figure 3.38). The mean concentration of 

silicon in the sediments of Guánica Bay is 

84,726 μg/g (Table 3.8), which is within the 

range of values observed elsewhere in the 

region (Table 3.4). Statistically, the North 

Bay had higher silicon concentrations than 

any of the offshore strata and the Central 

Bay is higher than eastern offshore (Dunn 

Method, α=0.05). 

Silicon in Coral Tissues 

Silicon was not measured in coral tissues. 

Figure 3.37. Concentrations of selenium in coral (mustard hill coral). 

Figure 3.38. Concentrations of silicon in sediments. 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

93 Contaminants 

Silver in Sediments 

The highest concentration of silver detected in 

the sediments of Guánica Bay is 0.174 μg/g at 

North Bay site NB01 (Figure 3.39). The mean 

concentration of silver is 0.019 μg/g (Table 

3.8), which is within the range of reported values for the region (Table 3.4). No sediment 

sites in Guánica Bay exceeded any thresholds 

or guidelines for silver. There are no significant differences between any strata for silver 

concentrations in this study (Dunn Method, 

α=0.05). 

Silver in Coral Tissues 

Silver was detected in coral tissues at values 

lower than observed in the sediments (Figure 

3.40), with a mean of 0.004 μg/g (Table 3.9) 

which are similar levels to what has been observed elsewhere in the region (Table 3.6). 

There are no statistically significant differences between strata for silver (Dunn Method, 

α=0.05). 

Figure 3.39. Concentrations of silver in sediments. 

Figure 3.40. Concentrations of silver in coral (Porites astreoides). 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

94 Contaminants 

Tin in Sediments 

The highest concentration of tin detected in 

this study is 3.93 μg/g at the watershed site 

WS108 (Figure 3.41). The mean concentration of tin in Guánica Bay sediments is 0.830 

μg/g (Table 3.8), which is similar to what 

has been observed elsewhere in the region 

(Table 3.4). Tin concentrations are higher in 

the North Bay and Central Bay strata when 

compared with the central and western offshore strata (Dunn Method, α=0.05). 

Tin in Coral Tissues 

Concentrations of tin in coral tissues were 

lower than concentrations observed in sediments, with a mean of 0.07 μg/g (Table 3.9), 

which is similar to what has been reported 

for other systems in the region (Table 3.6). 

Tin was detected in coral tissues only in the 

central stratum (i.e., immediately offshore 

from the Bay; Figure 3.42). Interestingly, tin 

was the only contaminant for which there is 

a statistically significant difference between 

strata for corals (Dunn Method, α=0.05), but 

it is likely because of the prevalence of nondetects in the eastern and western strata 

rather than unusually high tin in the central 

stratum. 

Figure 3.41. Concentrations of tin in sediments. 

Figure 3.42. Concentrations of tin in coral (mustard hill coral). 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

95 Contaminants 

Sewage Indicators in Sediments 

C. perfrigens was detected in 23 of 33 sediment samples collected, including every 

site in the bay and watershed, with a maximum of 3311 CFU/g (colony forming units 

per gram) at a site in the North Bay (Figure 

3.43) and a mean of 454 CFU/g. All sites with 

detections were relatively close to shore. 

Statistically, C. perfrigens was higher in the 

North Bay and Central Bay than eastern 

offshore and western offshore strata (Dunn 

Method, α=0.05). This is a similar range of 

values that has been reported elsewhere 

in Puerto Rico (Pait et al., 2007; Pait et al., 

2010). Sources of the elevated levels of C. 

perfringens would include wastewater treatment plants (WWTP) or septic systems that 

discharge to Guánica Bay or the Rio Loco, 

along with possible animal sources from agriculture in the Lajas Valley. 

Although C. perfringens is a common cause 

of foodborne illnesses, no health guidelines 

exist for concentrations of C. perfringens in 

sediments. A more severe form of the disease is often fatal and results from ingesting 

large numbers of the active bacteria. This 

pathogen also has the capability of forming 

spores which can persist in soils and sediments in areas subject to human and animal fecal pollution. 

Relationship of Contaminants with Grain Size, Total Organic Carbon and Lipid Content

None of the sediment contaminants measured in this study were well correlated (Spearman correlation) with percent 

total organic carbon (TOC). This is somewhat surprising given the tendency for contaminants, especially organics, to 

bind to sediments with higher organic content. Conversely, all sediment contaminants, with the exception of cadmium, 

HCH, monobutyltin and dibutlytin, are significantly correlated with grain size (percent fine, defined as sum of silt and clay 

fractions). However, correlation coefficients (Spearman ρ) are only above 0.7 for mercury, lead, PAHs, chlordane, PCBs 

and PAHs, indicating that these analytes are well correlated with grain size. When this subset of analytes is normalized 

to grain size, the statistical analysis of differences between strata changes; specifically, there are far fewer differences 

between the strata (mercury, lead and chlordane have no statistically significant differences between strata). While this 

highlights the importance of grain size in understanding spatial patterns, it is important to consider that from an ecological 

response perspective, higher concentrations, whether driven by grain size or some other pattern, can be detrimental to 

organisms in the ecosystem. Coral tissue contaminants were not significantly correlated with tissue lipid content (Spearman, α=0.05). 

Surface Water Temperature, Salinity and Dissolved Oxygen

Surface water YSI data (temperature, salinity and dissolved oxygen) for the coral sampling sites are shown in Table 3.11. 

There is very little variability between sites for these three parameters indicating fairly uniform offshore surface water 

characteristics. The only difference between strata is for temperature, for which the western strata is significant cooler 

than the central strata (Dunn Method, α=0.05). The measurements in the western strata were made in the early morning, 

whereas the measurements in the central strata were made mid-day. This suggests that radiant heating of the surface 

water explains this observed difference. 

Interpretation of Watershed Sites

Caution must be used when interpreting observed concentrations of contaminants in the three watershed sites from 2009 

(Figure 3.1) and the supplemental watershed sites from 2013 (see Appendix B, Figure B.12). First, these sites were not 

randomly selected and therefore cannot be included in the statistical analysis by strata of the sites selected via stratified 

Figure 3.43. Concentrations of C. perfringens in sediments. 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Contaminants 

ρ=0.96 

random design. Second, these sites repre- Table 3.11. YSI data from coral sampling sites (depth=0.5 m). 

sent a very different hydrologic environment 

than the sites in the bay and offshore. It 

is not clear to what extent deposited sediments are retained at these sites; based on 

field observations, it seems likely that some 

of the stream sites are probably scoured 

during large storm events. The site closest 

to the mouth of the Rio Loco (i.e., the farthest downstream watershed site) is more 

likely to be a depositional area which may 

retain significant sediments and associated 

contaminants. Additionally, it is tidally influenced, and its contaminant concentration 

may reflect both watershed inputs, as well 

as reverse flow from the bay. Presence of 

contaminants in the stream sites may shed 

some light on where pollutants are originating from, but these sites, in the absence of 

other information about pollutant sources, 

cannot provide definitive information. Results for selected analytes from the supplemental sampling are shown in Appendix B 

(Figures B.13-B.18). Chlordane is widely 

distributed in the watershed (Appendix B, 

site strata do temp salinity Conductivity 

CC056 Central 5.92 29.1 34.4 56.6 

CC057 Central 6.13 28.7 34.2 52.1 

CC058 Central 5.79 28.9 34.4 52.3 

CC060 Central 6.13 29 34.2 55.9 

CC061a Central 6.04 29 34.1 55.8 

EC031 Eastern 5.89 28.7 34.5 55.2 

EC032 Eastern 6.11 28.5 34.3 55.7 

EC034 Eastern 5.89 28.5 34.5 55.8 

EC041a Eastern 5.91 28.4 34.3 55.7 

EC045a Eastern 5.51 28.6 34.5 56.1 

WC081 Western 6.1 28.8 34.2 52.2 

WC082 Western 7.04 28.1 34.4 52.3 

WC083 Western 6.04 28.1 34.4 55.5 

WC084 Western 5.91 28.2 34.5 55.8 

WC085 Western 5.85 27.8 34.5 52.7 

Figure B.13). This is likely due to its wide use as an insecticide, including for termites, combined with its environmental 

persistence. PCBs do not appear to be coming from the watershed (Appendix B, Figure B.14). It is not clear if there is 

a near bay source of PCBs that is leaching into the bay via the stormwater outflow pipes or via groundwater, or if these 

stream values represent contamination present in the bay being transported to these sites via tidal actions. Similarly, DDT 

does not appear to have a strong watershed stream source (Appendix B, Figure B.15), which is surprising given its historical widespread use in agriculture and for mosquito control. Nickel (Appendix B, Figure B.16) and chromium (Appendix B, 

Figure B.17) are quite elevated across the watershed which suggests some sort of diffuse, or possibly natural source of 

these metals. Geological characterizations of southwest Puerto Rico have identified stream sediment anomalies for both 

nickel and chromium (USGS, 1998). This is attributed to these metals natural presence in the characteristic geology of 

the area (podiform chromite terrane). It is possible that anthropogenically enhanced erosion is exacerbating naturally high 

metals levels, resulting in the usually high marine sediment metals concentrations for nickel and chromium. Zinc is high 

near the outflow pipes near the bay (Appendix B, Figure B.18) which may be indicative of an urban automobile source 

(i.e., car tire dust; Councell et al., 2004). 

Potential Point Sources of Pollutants in 

the Watershed 100000 

Pollutant specific non-point sources are 90000 discussed above. A review of U.S. EPA National Pollution Discharge Elimination Sys- 80000 

tem permits for the subwatersheds of the 70000 study region does not point to any obvious 

dischargers that could explain the elevated 

levels of pollution in this study area (USEPA, 2013). All of the permitted dischargers 

within the watershed are drinking water and 

iron (ug/g) 60000 

50000 

40000 

wastewater treatment plant facilities, none 

of which have discharged large amounts 30000 

of metals or organic pollutants. There is 20000 an active landfill in the eastern portion of 

the study area (Figure 3.1) which could be 10000 

a source of a variety of pollutants. Historically, there was a chemical plant (Gonzalez 0 

0 10000 20000 30000 40000 50000 60000 70000 

Chemical Industries), which manufactured Aluminum (ug/g) 

ammonia fertilizer and sulfuric acid (Chem. 

Eng. News, 1957). While it is possible that Figure 3.44. Correlation of sediment aluminum concentrations with sediment iron 

concentrations. ρ value is Spearman rho (α=0.05). this production facility contributed to the pollution legacy of the bay, there is no obvious, 

documented link between these products and the type of pollution observed in this system.
 

96 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Contaminants 

800 

Additionally, because the bay is oriented 

on a north-south axis, latitude was used 

as a proxy for relative strength of water- 700 

shed source/dilution within the bay. In other 600 words, within the watershed and bay, if the 

watershed was a strong source of an indi- 500 

ρ=0.92 

vidual pollutant it would be expected that 

the more northerly sites would be most impacted by watershed and the more southerly 

sites less so (due to dilution). Latitude was 

nickel (ug/g) 400 

300 significantly but weakly correlated (Spearman, ρ=0.48) with the sewage indicator C. 

perfringens, suggesting a watershed-based 

source of sewage, rather than discharges 

200 

from boats. Latitude was also significantly 

correlated with concentration (Spearman, 

α=0.05) for all metals except silver, arsenic, 

100 

0 

0 10000 20000 30000 40000 50000 60000 70000 

lead, selenium and mercury, suggesting a 

strong watershed source of these metals. 

The strongest relationships were for iron 

(ρ=0.87), silicon (ρ=0.80), nickel (ρ=0.85), 

chromium (ρ=0.84) and zinc (ρ=0.78). However, because metals are naturally occurring 

in the earth’s crust, it is unclear if these are 

Aluminum (ug/g) 

Figure 3.45. Correlation of sediment aluminum concentrations with sediment nickel 

concentrations. Red diamonds indicate higher than expected (relative to aluminum) 

concentrations of nickel. ρ value is Spearman rho (α=0.05). 

2500 

natural or anthropogenic sources. Another 

way to potentially examine the nature of the 

source of these metals is to look at the ra­ 2000 

tio of each metal to aluminum, the primary 

element in the earth’s crust and generally 

not considered to be a pollutant. If a metal 

is well correlated with aluminum, it is more 

likely to have a natural (erosion) source 

(see also Apeti et al., 2012). All metals with 

the exception of silver were significantly correlated with aluminum (Spearman, α=0.05). 

Chromium (ug/g) 1500 

1000 

ρ=0.90 

0 10000 20000 30000 40000 50000 60000 70000 

Elements which make up large portions of 500 

the earth’s crust (e.g. silicon and iron) are 

especially well correlated with aluminum 

(e.g., Figure 3.44). Other metals, such as 0 

nickel and chromium, were also well correlated with aluminum, although sites with dis- Aluminum (ug/g) proportionately high concentrations (relative 

to aluminum were observed (Figures 3.45 Figure 3.46. Correlation of sediment aluminum concentrations with sediment 

and 3.46). These “outliers” may represent chromium concentrations. Red diamonds indicate higher than expected (relative to 

anthropogenic sources of these metals are aluminum) concentrations of chromium. ρ value is Spearman rho (α=0.05). 

prevalent at those sites. 

Fate of Contaminants from Guánica Bay

In general, pollutant levels were highest inside the bay itself and lower offshore. In order to test if the easterly flow from 

Guánica Bay is having a pollutant impact to the west, multivariate nonparametric tests were conducted correlating contaminant concentration in sediments (offshore strata only) and corals to longitude (i.e., long shore position). In general, 

contaminant distributions were not well correlated with longitude (Spearman α=0.05). A negative correlation was found 

between DDT in coral tissue concentration and longitude, suggesting that DDT concentrations increase from east to west 

(Spearman Rho = -0.6096). However, this pattern was not observed in sediment data. It is possible that offshore currents 

are sufficient to “flush” the offshore sediment system frequently; whereas pollutants can accumulate in the bay because 

it is not as exposed to ocean currents. 

Ecological Significance of Findings

Since trace elements occur naturally in the environment, including some which are micronutrients for many organisms, 

the mere presence of trace elements in corals tissues may or may not represent a stressor to the coral. However, organic 

contaminants serve no positive purpose in coral physiology. At best, the organic pollutants might not harm the corals in 

small concentrations, but at worst these may represent serious stress to coral health and physiology. 

97 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

98 Contaminants 

While some studies exist linking specific contaminants to deleterious effects in corals (e.g., Solbakken et al., 1984; 

Peachey and Crosby, 1996; Reichelt-Brushett and Harrison, 2005; Guzman-Martinez et al., 2007), further research is 

needed to link observed contaminants in coral tissues with sub-lethal responses in the coral. This might be accomplished 

by ecotoxicological studies in coral mesocosm experimental facilities, or in the field with genetic analysis of stressor 

genes in combination with field measurements of contamination (e.g., Edge et al., 2005). 

In the absence of experimental ecotoxicological studies on the causal relationships between contaminants and coral 

reef communities, a number of multivariate statistical methods could be used to examine the correlational relationships 

between contaminants and the biological communities (e.g., fish and corals) they may impact. Among these methods are 

regression-based techniques to model the response of biological variables (e.g., species presence/absence, abundance, 

biomass) to contaminants as well as classification and ordination methods (see Legendre and Legendre, 1998 for detailed descriptions of many of these methods). 

These multivariate statistical methods generally require spatially and temporally co-located environmental and species 

sample data. Although co-located data (or even approximately co-located within the range of spatial autocorrelation) was 

not available from the contaminant and biological datasets described in this chapter and in Chapter 2, respectively, as an 

exploratory analysis a simple correlation analysis was performed using contaminant sample data and modeled predictions of biological data at the locations of the contaminant samples. Although not statistically robust, this was intended as 

a demonstration of the type of analysis that could be performed with co-located data. Geostatistical methods were used 

to generate continuous gridded model predictions at 30m horizontal grid resolution for fish biomass, fish abundance, fish 

species richness, fish diversity, total coral and coral species richness from the point sample data in the dataset presented 

in Chapter 2. Geostatistical methods are based on the premise that neighboring samples are more similar than those farther apart and that the spatial structure of the data (spatial autocorrelation) can be estimated, modeled and used to make 

predictions at locations that have not been sampled (Cressie, 1993). For each of the biological variables, spatial autocorrelation in the point sample data was quantified and modeled using semivariogram analysis. Fitted semivariogram model 

parameters were used to perform ordinary kriging of the sample data. Values for each of the biological variables were 

then extracted from the model predictions at the locations of contaminant sample data, and Pearson’s product-moment 

correlation coefficients were calculated for each biological variable-contaminant pair and tested for statistical significance 

(α=0.05). As an example of the potential utility of this type of analysis, the tests showed a relatively strong (r >0.6) negative 

relationship between total PCBs and all the biological variables except fish biomass and diversity. 

It is important to note, however, that a number of statistical assumptions are violated in using values extracted from the 

modeled biological datasets to perform correlation analysis in this manner and that the datasets generated by geostatistical methods represent statistical model predictions, and as such may vary greatly in their accuracy and may or may 

not reflect actual conditions at any given location. At the same time, this exploratory analysis suggested some potential 

relationships between contaminants and coral reef communities that could be further explored through the collection of 

additional and spatially and temporally co-located data. In addition, semivariogram analysis of the sample datasets can 

inform future survey design by indicating the range of spatial autocorrelation in the variables of interest. 

ConClusions 

Overall, the chemical contamination of Guánica Bay is higher than what has been observed in other systems in Puerto 

Rico. For some analytes, the bay is polluted relative to national historic sediment values. High levels of pollution are generally limited to inside the bay itself. While there is evidence of transport of pollutants to the offshore coral reef ecosystem, 

contaminant concentrations in coral tissues in this study were consistent with concentrations seen in other regions of 

Puerto Rico. 

There are a variety of potential sources of pollution to Guánica Bay (e.g., WWTP, landfill, legacy industries, agriculture, 

boating, impervious surface runoff), but there is no one “smoking gun” which identifies any one source of primary concern. 

This speaks to the need for an integrated management strategy which addresses multiple sources of land-based pollu­
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

99 Contaminants 

 

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US Geological Survey (USGS). 1998. Geology, Geochemistry, Geophysics, Mineral Occurrences and Mineral Resource Assessment 

for the Commonwealth of Puerto Rico. Open File Report 98-38. http://pubs.usgs.gov/of/1998/of98-038/ Accessed 7/31/2013. 

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Chapter 4: terrigenous sedimentation Patterns at Reefs 

Adjacent to the guánica bay Watershed
 

Clark Sherman1,3, Raquel Hernandez1, Yahaira Hutchinson1 and David Whitall2 

bACkgRound 

Increased terrestrial runoff due to coastal development and watershed land-use changes is one of the primary threats to 

coral reef ecosystems worldwide (Burke et al., 2011). Elevated sedimentation levels have been linked to several types 

of reef degradation including fewer coral species, less live cover, reduced recruitment, lower growth rates and calcification, altered species composition and lower rates of reef accretion (ISRS, 2004; Rogers, 1990). Sedimentation can cause 

burial and smothering of corals and tissue necrosis (Erftemeijer et al., 2012). Increased terrestrial runoff into Guánica 

Bay and adjacent coastal waters is a primary concern of the Guánica Bay Watershed Management Plan (CWP, 2008). 

The work presented here is a component of a larger effort to characterize reef communities and the chemical/biological 

stressors affecting them in order to inform decision-making, as well as serve as a baseline to quantify the effectiveness 

of implemented watershed restoration efforts. This work specifically seeks to address project needs by determining the 

composition and accumulation rates of terrigenous materials accumulating in Guánica Bay and on adjacent reefs. 

methodologY 

Study Area

The study area encompasses Guánica 

Bay (approximately 17° 57’ N, 66° 54.4’ W, 

mouth of bay) and adjacent nearshore reefs 

in southwest Puerto Rico (Figure 4.1). The 

insular shelf here extends ~3 to 5 km offshore before dropping steeply to oceanic 

depths from the shelf break at a depth of 

~20 m. The shelf contains both emergent 

and submerged linear reefs oriented roughly parallel to shore and rising from depths of 

~10-20 m. The reefs are separated by open 

sandy and hardbottom areas (Kendall et al., 

2001). In order to assess the influence of 

Guánica Bay on the sedimentary dynamics 

of adjacent reefs, nine reef sites were selected along an ~14 km long, shore-parallel 

transect roughly centered on the mouth of 

the bay. In addition, two (non-reef) sites 

were chosen to characterize sedimentary 

dynamics of Guánica Bay itself. These are 

sites S01 at the mouth of the Rio Loco where 

it empties into Guánica Bay and site S02 at 

the mouth of Guánica Bay where it opens 

into adjacent coastal waters. The study area 

was divided into four strata based on proximity to the bay. These are Bay (sites S01 

and S02), East (sites S08, S09 and S10), 

South (sites S06, S07 and S11) and West 

(sites S03, S04 and S05). 

Sediment Traps

Sediment traps were clear plastic tubes 30-cm high with an internal diameter of 6.4 cm (Figure 4.2). Tops of the traps 

were covered with a 1 cm2 nylon mesh to prevent entry of small fish and invertebrates. Traps were secured with plastic 

cable ties to steel rods that were driven into the hard reef surface. Due to the soft mud and sand substrate at the Bay sites 

(S01 and S02), the steel rods were attached to a plastic crate that was anchored to the seafloor with a cinder block. In 

all cases, the traps were situated so that the tops of the traps were ~60 cm above the surrounding seafloor. Similar traps 

and techniques have been used in previous studies (e.g., Bothner et al., 2006; Storlazzi et al., 2009). At reef sites, a pair 

Figure 4.1. Map of study area showing location of sediment traps. Study area is 

divided into four strata based on proximity to Guánica Bay. These are Bay, East, 

South and West. 

1. University of Puerto Rico, Mayaguez

2. NOAA/NOS/NCCOS

3. Corresponding author, clark.sherman@upr.edu 

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of duplicate sediment traps was placed at 

a depth of ~10 m. At three of the reef sites 

(S04, S07 and S10), an additional pair of 

traps was placed at a depth of ~5 m and are 

designated as S04S, S07S and S10S, respectively. At the Bay sites, traps were situated at depths of 2 m (S01) and 8 m (S02). 

Traps were collected and processed monthly from August 2009 through July 2012. In 

some cases, weather or other logistical 

issues did not allow for the usual monthly 

collection and the traps were collected after 

an approximately two-month sampling interval. This includes December 2009-January 

2010, August-September 2011, April-May 

2012 and June-July 2012. 

Laboratory Analyses

In the laboratory, material from one trap of 

each duplicate pair was separated by wet 

sieving into a coarse/sand fraction (>63 μm) 

and fine/mud fraction (<63 μm). Samples 

from all traps (sieved and unseived) were 

oven dried at 60°C and dry weight was determined. Monthly totals were taken as the average of each pair of traps. Trap accumulation rates were determined as 

total weight (mg)/area of trap opening (cm2

)/number of days in the field and expressed as mg cm-2 d-1. A subset of samples 

was ground in an agate mortar for compositional analyses. Bulk carbon composition, including total carbon, total inorganic 

carbon and total organic carbon, was determined by carbon coulometry techniques (Engleman et al., 1985) conducted at 

the Limnological Research Center/National Lacustrine Core Facility, University of Minnesota – Twin Cities. Coulometric 

results were converted to percent calcium carbonate, percent organic material and percent other/terrigenous material. 

Wave and Rainfall Data 

Wave data are from the Caribbean Coastal Ocean Observing System Ponce Buoy located at 17° 51.61 ́N, 66° 31.42 ́W, 

~42 km southeast of the mouth of Guánica Bay. From this data set, average daily wave heights were determined for each 

sampling interval over the study period from August 2009 - July 2012. Gaps in wave data are due to technical issues or 

servicing of the buoy. Rainfall data were collected at the Isla Magueyes Marine Laboratories in La Parguera, Puerto Rico, 

~15 km west of the mouth of Guánica Bay. Data were taken from climatological records kept by the Bio-Optical Oceanography Laboratory, Department of Marine Sciences, University of Puerto Rico at Mayagüez. Total rainfall was determined 

for each sampling interval over the study period from August 2009 - July 2012. 

Statistical Analysis

Because the data was not normally distributed (Shapiro-Wilk test), non-parametric 

techniques (Dunn Method, α=0.05) were 

used to examine statistical differences between the strata. 

Results 

Trap accumulation data for the entire sampling period of August 2009 through July 

2012 are presented here. Bulk compositional data are presented only for the period of 

August 2009 through May 2011. 

Average Bulk Composition

Average composition of trap sediments in 

terms of percent calcium carbonate, percent 

organic material and percent terrigenous 

material is shown in Figures 4.3 and 4.4. 

Not surprisingly, the Bay sites consistently 

have higher percentages of terrigenous material than the reef sites, though there is a 

Figure 4.2. Simple tube traps used to collect suspended sediments. Sediment traps 

were clear plastic tubes 30-cm high with an internal diameter of 6.4 cm. Tops of 

the traps were covered with a 1 cm2 nylon mesh to prevent entry of small fish and 

invertebrates. Traps were secured with plastic cable ties to steel rods that were 

driven into the hard reef surface. Traps were situated so that the tops of the traps 

were ~60 cm above the surrounding seafloor. 

Figure 4.3. Average bulk composition of trap sediments from August 2009 through 

May 2011 given in weight percent calcium carbonate, organic material and 

terrigenous material for the coarse (>63 μm) and fine fractions (<63 μm). 

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considerable difference in composition between the two bay sites (S01 and S02). In 

all cases, the fine fraction (<63 μm) contains 

a higher percentage of terrigenous material. 

Organic contents are low, typically less than 

10% with an average of ~5%. Site S01 near 

the mouth of the Rio Loco in Guánica Bay 

has the highest average terrigenous content 

at ~87%, with the remainder roughly equally 

split between carbonate and organic material. In contrast, Site S02 at the mouth of 

Guánica Bay has an average terrigenous 

content of ~30%, with calcium carbonate 

and organic contents of ~65% and ~5%, 

respectively. Reef sites have an average 

percent terrigenous material that ranges 

from ~21% to 28%, with averages of 24% 

at East sites (S08, S09 and S10), 26% at 

South sites (S07, S06 and S11) and 23% at 

West sites (S03, S04 and S05). The remainder consists primarily of calcium carbonate 

(aragonite and magnesium calcite), representing in situ production, with an average 

of only ~5% organic material. 

Average Trap Accumulation Rates

Trap accumulation rates are highly variable 

on both spatial and temporal scales. Average accumulations rates are shown in Figures 4.4 and 4.5. Over the entire sampling 

period of August 2009 through July 2012 

(Figure 4.5), the Bay sites had average trap 

accumulation rates of 22 mg cm-2 d-1 (S01) 

d-1 and 25 mg cm-2 (S02), with 80-90% of 

this being fine-grained material (<63 μm). 

In general, these rates are higher than average accumulation rates at the reef sites 

over the same period, though two of the reef 

sites (S06 and S10) had average rates that 

met or exceeded those measured in the bay. 

Reef sites had average trap accumulation 

rates that ranged from 3 to 28 mg cm-2 d-1, 

with averages of 11 mg cm-2 d-1 at East sites 

(S08, S09 and S10), 18 mg cm-2 d-1 at South 

sites (S07, S06 and S11) and 8 mg cm-2 d-1 

at West sites (S03, S04 and S05). Trap sediments at South and West sites consisted of considerably more fine-grained 

material averaging 74% and 80%, respectively, while trap sediment at East sites averaged 54% fine-grained material. 

Temporal Patterns

Temporal patterns in trap accumulation and composition are shown in Figures 4.6 to 4.12. Figure 4.6 compares trap 

accumulation over time between the two Bay sites, S01 (Rio Loco mouth) and S02 (Guánica Bay mouth). Although the 

patterns are similar, there is not a consistent relationship between the two sites, indicating that separate drivers are affecting sedimentary dynamics at these sites. Terrigenous content at the river mouth is very uniform and remains within 

a few percent of the average value of 87% (Figure 4.7). Terrigenous content at the bay mouth is more variable ranging 

from 22-41%, but in most cases is very close to the average of 30%. Figure 4.8 and 4.9 provide more detail on sedimentary dynamics at the mouth of Guánica Bay (site S02), the pathway through which sediments from the bay must travel 

to reach adjacent reefs. In most cases, increases in trap accumulation correspond with decreases in the percentage of 

fine-grained material (Figure 4.8). This suggests that peaks in trap accumulation are associated with high-energy events 

during which fine-grained material is not able to settle. In general, trap accumulation and terrigenous accumulation (trap 

accumulation rate multiplied by percent terrigenous material) vary together (Figure 4.9). In contrast, the percent terrigenous typically decreases during peaks in trap accumulation. Thus, increases in trap accumulation do not necessarily 

correspond to increases in the relative amount of terrigenous material. 

Figure 4.4. Average trap accumulation from August 2009 through May 2011, 

showing percent terrigenous material. 

Figure 4.5. Average trap accumulation rate from August 2009 through July 2012, 

showing percentages of coarse-(>63 μm) and fine-grained (<63 μm) material. 

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Figure 4.6. Trap accumulation rates by month from August 2009 Figure 4.7. Percent terrigenous accumulation by month from 

through July 2012 for the two Bay sites, S01 at the mouth of Rio August 2009 through May 2011 for the two Bay sites, S01 at the 

Loco and S02 at the mouth of Guánica Bay. mouth of Rio Loco and S02 at the mouth of Guánica Bay. 

Figure 4.8. Comparison of trap accumulation rate with percent 

fine-grained material (<63 μm) by month from August 2009 

through July 2012 for site S02 at the mouth of Guánica Bay. Note 

that increases in trap accumulation are typically associated with a 

decrease in the percentage of fine-grained material. 

Figure 4.9. Comparison of total trap accumulation rate, terrigenous 

accumulation rate and percent terrigenous material by month 

from August 2009 through May 2011 for site S02 at the mouth of 

Guánica Bay. Note that total and terrigenous accumulation rates 

vary together, while increases in trap accumulation rate are typically 

associated with decreases in percent terrigenous material. 

Figure 4.10. Comparison of average trap accumulation rates by 

month for the four different strata of the study area (Bay, East, 

South and West). Note that the reef sites (East, South and West) 

exhibit similar temporal patterns, while the Bay sites behave 

somewhat differently. The record is punctuated by several highmagnitude events, most notably October 2010, July 2011 and 

June-July 2012. 

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Table 4.1. Results of Dunn Method (α=0.05) to determine differences between strata for total sedimentation rate and terrigenous 

sedimentation rate. Note: p-values in italics denote statistical significance. 

Variable stratum stratum p-Value 

Sedimentation Rate River Mouth East <0.001 

Sedimentation Rate River Mouth Central 0.004859 

Sedimentation Rate West East 1 

Sedimentation Rate River Mouth Bay Mouth 1 

Sedimentation Rate West Central 0.303524 

Sedimentation Rate East Central 0.079343 

Sedimentation Rate Central Bay Mouth 0.003877 

Sedimentation Rate West Bay Mouth <0.001 

Sedimentation Rate West River Mouth <0.001 

Sedimentation Rate East Bay Mouth <0.001 

Terrigenous sedimentation rate River Mouth East <0.001 

Terrigenous sedimentation rate River Mouth Central <0.001 

Terrigenous sedimentation rate River Mouth Bay Mouth 0.772657 

Terrigenous sedimentation rate West East 1 

Terrigenous sedimentation rate West Central 0.058889 

Terrigenous sedimentation rate East Central 0.024139 

Terrigenous sedimentation rate Central Bay Mouth 0.012323 

Terrigenous sedimentation rate West Bay Mouth <0.001 

Terrigenous sedimentation rate East Bay Mouth <0.001 

Terrigenous sedimentation rate West River Mouth <0.001 

Figure 4.10 compares trap accumulation 

rates among the four strata of the study 

area. Table 4.1 shows the statistical differences (Dunn Method, α=0.05) between the 

strata. Reef sites (East, South and West) 

exhibit a very similar temporal pattern with 

concomitant increases and decreases in 

trap accumulation, indicating a uniform driver of sedimentary dynamics among the reef 

sites. The Bay stratum displays a slightly 

different temporal pattern and there is not 

a consistent temporal relationship between 

the Bay and the reef sites. East and West 

sites generally have similar accumulation 

rates and remain below ~10 mg cm-2 d-1 

much of the time. South sites display a similar temporal pattern in accumulation to the 

other reef sites, but typically record higher 

rates. The record is punctuated by several 

high-magnitude events with accumulation 

rates that, in some cases, are an order of 

magnitude higher than the long-term average, most notably October 2010, July 2011 

and June-July 2012. 

To examine sedimentary dynamics at reef sites in more detail, results from the South sector are shown in Figures 4.11 

and 4.12. These are representative of sedimentary dynamics at the other reef sites. At the South sites, over much of the 

study period, trap accumulation remains close to or below the long-term average of ~18 mg cm-2 d-1. The exceptionally 

high rates recorded during October 2010 greatly affect the long-term average. Removing this one event from the record 

would reduce the long-term average by about 27% down to ~ 13 mg cm-2 d-1. Peaks in trap accumulation (e.g., October 

2010, July 2011 and June-July 2012) are associated with decreases in percent fine material (Figure 4.11). As with site 

S02 at the mouth of Guánica Bay (Figure 4.8), this indicates that these exceptionally high accumulation rates are associated with high-energy events during which fine-grained material is not able to settle. In general, total trap accumulation 

and terrigenous accumulation vary directly together (Figure 4.12). In contrast, the percent terrigenous has more of an inFigure 4.11. Comparison of trap accumulation rate with percent fine-grained material 

(<63 μm) by month from August 2009 through July 2012 for South sites (S06, S07, 

S07S and S11). Note that increases in trap accumulation are typically associated 

with a decrease in the percentage of fine-grained material. 

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verse relationship with total trap accumulation. Peaks in trap accumulation are associated with decreases in percent terrigenous 

(e.g., October 2010), while the highest percent terrigenous values are associated with 

relatively low (below average) accumulation 

rates. In addition, while accumulation rates 

are highly variable, the percent terrigenous 

material is relatively uniform, remaining 

within ~3% of the long-term average over 

most of the record. 

disCussion 

Results of a three-year sediment-trap study 

establish an important baseline of spatial 

and temporal trends in sediment accumulation rates and composition at nearshore 

reefs adjacent to the Guánica Bay watershed. In general, Bay sites (S01 and S02) 

had higher accumulation rates and a higher 

percentage of terrigenous material than the 

reef sites (Figures 4.4 and 4.5). While terrigenous content at the mouth of the Rio Loco 

(S01) was fairly uniform and remained within a few percent of the average value of 87%, terrigenous content at the mouth 

of Guánica Bay (S02) was more variable and considerably lower, ranging from 22-41%, but in most cases remaining close 

to the average of 30% (Figure 4.7). This marked decrease in terrigenous content from the mouth of the Rio Loco to the 

mouth of Guánica Bay is likely a function of two factors. First, it indicates that Guánica Bay serves as an important sink of 

terrigenous materials delivered to the coast by the Rio Loco. Second, the composition of sediments accumulating at the 

mouth of the bay is greatly affected by in situ production of carbonate sediments on the insular shelf. In addition, because 

site S02 is situated within the primary conduit through which terrigenous sediments from the bay must pass to reach 

adjacent reefs, the composition of trap sediments at S02 represents an upper end number of what would be expected at 

adjacent reefs. That is, reef sites would not be expected to receive sediments with a terrigenous content above ~30%, 

the average at site S02. Indeed, all reef sites have average terrigenous contents below 30%, ranging from 21% to 28%. 

All reef sites exhibit similar temporal patterns of trap accumulation rates (Figure 4.10), indicating that they are responding 

to the same driver (or drivers) of sedimentary dynamics. The similarity of these long-term records also indicates that the 

sediment traps were recording actual trends in sedimentary dynamics and not isolated occurrences at an individual site. 

Among the reef sites, South sites (S06, S07 and S11) generally have higher average trap accumulation rates and higher 

percent terrigenous material than East and West sites (Figures 4.4 and 4.5). This is consistent with their location just to 

the west of the mouth of Guánica Bay and mean westward flowing coastal currents along the shelf (Warne et al., 2005). 

Average trap accumulation rates and percent terrigenous material among the reef sites are comparable to, but slightly 

higher than accumulation rates and percent terrigenous material measured at inner- and middle-shelf reefs off La Parguera, a few kilometers to the west of Guánica (Hernandez et al., 2009). This is consistent with the reefs off La Parguera 

being further removed from terrestrial influence with no major river inputs (Hernandez et al., 2009; Warne et al., 2005). 

However, because different types of sediment traps were used for the La Parguera study, it is difficult to directly compare 

these results (Storlazzi et al., 2011). 

Average chronic sedimentation rates of 10 mg cm-2 d-1 have been proposed as a threshold for initiating stress responses 

in coral reefs including fewer coral species, reduced live coral cover, lower growth rates and slower rates of reef accretion 

(Rogers, 1990). Pastorok and Bilyard (1985) suggested that rates of 10-50 mg cm-2 d-1 could be considered as moderate 

to severe. However, other studies indicate that some corals and reefs can tolerate sedimentation rates >400 mg cm-2 d-1 

(Erftemeijer et al., 2012 and references therein). Still, studies by Nemeth and Nowlis (2001) and Smith et al. (2008) in 

the U.S. Virgin Islands lend support to 10 mg cm-2 d-1 as a reasonable “working” threshold for the region and to increased 

sedimentation as a primary driver of reef degradation at nearshore sites. In the current study, all South sites have average 

trap accumulation rates in excess of 10 mg cm-2 d-1 and, thus, may be considered at least moderately sediment stressed. 

In contrast, most East and West sites have average trap accumulation rates below 10 mg cm-2 d-1. Only site S10 in the 

East sector and S03 in the West have average trap accumulation rates above 10 mg cm-2 d-1. 

Trap accumulation rates are highly variable on both spatial and temporal scales and can range by an order of magnitude 

from one monthly sampling interval to the next. In contrast, sediment composition remains relatively uniform over time 

(Figures 4.9, 4.10 and 4.12). The rough inverse relationship between trap accumulation rate and percent fine-grained material (Figures 4.8 and 4.11) suggests that elevated trap accumulation rates are associated with high-energy events, such 

as wave events that can resuspend large amounts of bottom sediments. Terrigenous accumulation rates vary directly with 

Figure 4.12. Comparison of total trap accumulation rate, terrigenous accumulation 

rate and percent terrigenous material by month from August 2009 through May 

2011 for South sites (S06, S07, S07S and S11). Note that total and terrigenous 

accumulation rates vary together, while increases in trap accumulation rate are 

typically associated decreases in percent terrigenous material. 

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total trap accumulation. While terrigenous accumulation rates are variable over time, the percentage of terrigenous material remains fairly constant, or deceases slightly during peak accumulation events (Figure 4.13). Even the percentage of 

terrigenous material in the fine fraction remains relatively constant over time. Thus, peaks in trap accumulation rates do 

not correspond to increases in the relative amount of terrigenous material in trap sediments, i.e., they do not correspond 

to influxes of new terrigenous material. Similar temporal patterns in accumulation rates among the sites without corresponding changes in composition of sediments point to resuspension of bottom sediments by wave action as a primary 

driver of sedimentary dynamics at these reefs. This is further supported by comparison of trap accumulation rates with 

rainfall and wave height records (Figure 4.14). 

Figure 4.13. Terrigenous accumulation rates by month in the four 

strata of the study area from August 2009 through May 2011 (top). 

Percent terrigenous accumulation by month in the four strata of the 

study area from August 2009 through May 2011 (center). Percent 

terrigenous accumulation in the fine fraction (<63 μm) by month 

in the four strata of the study area from August 2009 through May 

2011(bottom). Note that while terrigenous accumulation rates are 

variable, the percentage of terrigenous accumulation remains 

quite constant both in the whole sample and in the fine fraction. 

320 

300 2009 2010 2011 2012 

280 Rain (mm) 

260 

240 

) mm

220 

200 

all (

180 

ainf

160 

ly r

140 

120 

Total Month

100 

80 

60 

40 

20 

0 

2.5 

2009 2010 2011 2012 

Avg Wv Ht 

2 

m) ight (

Max 

1.5 

Wave he

1

Average Daily 

0.5 Min 

0 

170 

160 2009 2010 2011 2012 

140 

150 Bay Total Rate 

East Total Rate 

South Total Rate 

130 West Total Rate 

120 

te Ra

110 

100 

-1 -2 day 

tion 

90 

ula

80 

um

cm mg 

70 

60 

Trap Acc

50 

40 

30 

20 

10 

0 

A S O N DJ F M A M J J A S O N D J F M A M J J AS O N D J F M AM JJ 

Figure 4.14. Total rainfall during each of the sampling intervals 

from August 2009 through July 2012 (top). Average daily wave 

height during each of the sampling intervals from August 2009 

through July 2012 (center). Solid line shows average daily wave 

height during each sampling interval. Vertical bars show range of 

average daily waves heights during each interval. Average trap 

accumulation rates by month for the four different strata of the 

study area (Bay, East, South and West; bottom). Note that highmagnitude events in October 2010, July 2011 and June-July 2012 

correlate with the three highest (max) values of average daily 

wave height, each greater than 2 m. 

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Three notable peaks in trap accumulation occur in October 2010, July 2011 and June-July 2012. While these are intervals 

of moderate to high rainfall, they do not stand out in the rainfall record and other intervals with similar or higher levels of 

rainfall do not correspond to such high peaks in trap accumulation. When compared to the wave height record, the peaks 

in trap accumulation in October 2010, July 2011 and June-July 2012 correspond to the three highest values of average 

daily wave height recorded over the three-year study period, each over 2 m. 

When assessing the degree to which a 

reef is potentially influenced by terrigenous 

sedimentation, it is important to consider in 

conjunction both total sediment accumulation and the percentage of terrigenous 

material (Figure 4.15). Reefs negatively 

impacted by terrigenous sedimentation 

would be expected to plot towards the upper right in Figure 4.15, i.e., they would be 

experiencing both high sediment accumulation rates along with a high percentage of 

terrigenous material in the sediment. Note 

that site S02 at the mouth of Guánica Bay 

plots furthest to the right with the highest 

percentage of terrigenous material as well 

as a high average accumulation rate, which 

is consistent with this site’s location. All reef 

sites plot to the left of S02. Sites S07 and 

S07S (S07S are shallow traps at 5 m water 

depth, just adjacent to S07) plot closest to 

S02 consistent with their close proximity to 

the mouth of Guánica Bay and indicative of 

terrigenous sediment stress. Site S06 also 

plots in the upper right, suggestive of terrigenous sediment stress and consistent with 

its location just down current from the mouth 

of Guánica Bay. It has the highest average 

accumulation rate with a moderate percentage of terrigenous material. Together, these 

factors result in S06 having the highest average terrigenous accumulation rate of the 

reef sites. Among the other reef sites spatial 

(i.e., east-west) trends are not readily apparent as plotted in Figure 4.15. 

Guánica Bay is certainly a source of terrigenous materials to the adjacent coastal ocean. Observations by field personnel 

during the course of the study frequently included visible plumes of turbid water exiting the bay, and this is reinforced by 

the high terrigenous content of those sites closest to the mouth of the bay, i.e., S02, S07 and S07S. The lack of consistent 

east-west trends among the other sites in either trap accumulation rates or percent terrigenous material is suggestive 

of several causative factors. First, the Guánica coast is an open, energetic and well-mixed system. Terrestrial inputs are 

quickly diluted by the large reservoir of shelf sediments. Terrigenous influx events are difficult to identify with sediment 

traps, because these events are typically coincident with storms and high waves when traps are primarily collecting resuspended, well-mixed sediments. Second, the assumption of relatively uniform westerly flow along the Guánica shelf may 

be overly simplistic. Terrigenous materials exiting Guánica Bay may be being transported in multiple directions, which 

would account for the lack of east-west trends relative to the mouth of the bay. However, this would suggest a general 

decrease in relative amounts of terrigenous materials with distance from the bay, which is not evident in trap samples. 

Finally, it is estimated that 1,000 to 4,300 t km-2 yr-1 of suspended sediment are discharged to coastal waters of south/ 

southwestern Puerto Rico, much of this delivered to the coast east of Guánica (Warne et al., 2005). Prevailing flow along 

the insular shelf could transport this material westward and constitute an important source of terrigenous sediments 

reaching the reefs off Guánica. 

ConClusions 

The Guánica coastline is an open, energetic and well-mixed system. Sediment trap accumulation rates are highly variable on both spatial and temporal scales. Low-frequency, high-magnitude, resuspension events are extremely important 

components of the sedimentary dynamics of these reefs. Sediment composition remains fairly uniform on both spatial 

and temporal scales. Spikes in the percentage terrigenous material (i.e., terrigenous influx events) are not evident. The 

uniform composition of trap sediments regardless of trap accumulation rate indicates that resuspension of bottom sediFigure 4.15. Average trap accumulation versus percent terrigenous material at all 

reef sites and at the mouth of Guánica Bay (S02). The arrow indicate potential for 

increased stress due to terrigenous sedimentation. Sites that plot in the upper right 

of the graph are exposed to higher level of terrigenous accumulation. 

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Sedimentation

ments is a primary driver of trap accumulation rates and patterns. Those sites closest to Guánica Bay show higher trap 

accumulation rates and percentage terrigenous material. However, there are no consistent east-west trends in either trap 

accumulation rates or percent terrigenous material, with respect to proximity to the bay. While Guánica Bay is a local 

source of terrigenous materials it is not necessarily the sole or primary source. Other up-current sources to the east are 

likely equally important. 

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Engleman, E.E., L.L. Jackson, and D.R. Norton. 1985. Determination of carbonate carbon in geological materials by coulometric titration. Chemical Geology 53: 125.
 

Erftemeijer, P.L.A., B. Riegl, B.W. Hoeksema, and P.A. Todd. 2012. Environmental impacts of dredging and other sediment disturbances on corals: A review. Marine Pollution Bulletin 64: 1737-1765.
 

Hernandez, R., C. Sherman, E. Weil, and P. Yoshioka. 2009. Spatial and temporal patterns in reef sediment accumulation and composition, southwestern insular shelf of Puerto Rico. Caribbean Journal of Science 45: 138-150.
 

ISRS (International Society for Reef Studies). 2004. The effects of terrestrial runoff of sediments, nutrients and other pollutants on coral 

reefs. International Society for Reef Studies. 18 pp.
 

Kendall, M.S., M.E. Monaco, K.R. Buja, J.D. Christensen, C.R. Kruer, M. Finkbeiner, and R.A. Warner. 2001. Methods used to map the 

benthic habitats of Puerto Rico and the U.S. Virgin Islands. NOAA National Ocean Service, Silver Spring, MD. 44 pp. 

Nemeth, R.S. and J.S. Nowlis. 2001. Monitoring the effects of land development on the near-shore reef environment of St. Thomas, 

USVI. Bulletin of Marine Science 69: 759-775.
 

Pastorok, R.A. and G.R. Bilyard. 1985. Effects of sewage pollution on coral-reef communities. Marine Ecology Progress Series 21: 

175-189. 

Rogers, C.S. 1990. Responses of coral reefs and reef organisms to sedimentation. Marine Ecology Progress Series 62: 185-202.
 

Smith, T.B., R.S. Nemeth, J. Blondeau, J.M. Calnan, E. Kadison, and S. Herzlieb. 2008. Assessing coral reef health across onshore to 

offshore stress gradients in the US Virgin Islands. Marine Pollution Bulletin 56: 1983.
 

Storlazzi, C., M. Field, and M. Bothner. 2011. The use (and misuse) of sediment traps in coral reef environments: theory, observations, 

and suggested protocols. Coral Reefs 30: 23-38.
 

Storlazzi, C.D., M.E. Field, M.H. Bothner, M.K. Presto, and A.E. Draut. 2009. Sedimentation processes in a coral reef embayment: 

Hanalei Bay, Kauai. Marine Geology 264: 140.
 

Warne, A.G., R.M.T. Webb, and M.T. Larsen. 2005. Water, sediment, and nutrient discharge characteristics of rivers in Puerto Rico, and 

their potential influence on coral reefs, U.S. Geological Survey Scientific Investigations Report 2005-5206. 58 pp. 

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Nutrients 

Chapter 5: spatial and temporal Variability in 

surface Water nutrients in and around guánica bay, Puerto Rico
 

David Whitall1,3 and Clark Sherman2 

bACkgRound 

Primary productivity in marine systems is most often limited by nitrogen, but phosphorus can be co-limiting under certain 

circumstances. Estuarine and coastal systems can vary from nitrogen limitation to phosphorus limitation over space and 

time. Nutrient enrichment can result in algal blooms, changes in algal community composition (including increasing occurrence and extent of harmful algal blooms) and increases in hypoxia/anoxia (Bricker et al., 2007). 

In tropical systems, excess nutrient loads can cause increases in macroalgal growth and can have deleterious effects on 

corals, such as macroalgae outcompeting and overgrowing corals. Furthermore, nitrogen and phosphorus can impact 

corals directly by lowering fertilization success (Harrison and Ward, 2001), and reducing both photosynthesis and calcification rates (Marubini and Davis, 1996). Useful reviews summarizing the biogeochemistry of nitrogen and phosphorus in 

coral systems have been previously published (e.g., McCook, 1999; Bell, 1992). 

Land-based contributions of nutrients to coastal systems originate from a variety of sources. Phosphorus and reactive 

nitrogen can enter the environment from chemical fertilizers (agriculture, lawns, golf courses), industrial sources, animal 

waste and human waste (Galloway et al., 2003). Additionally, nitrogen can be contributed from biological nitrogen fixation 

and atmospheric nitrogen deposition (originating from fossil fuel combustion and ammonia volatilization from agriculture; 

Mathews et al., 2002). 

Although a comprehensive watershed nutrient budget is beyond the scope of this study, both human waste and agriculture are potentially important sources of new nutrients to Guánica Bay. There are two wastewater treatment plant (WWTP) 

facilities in the study area. The primary facility, Puerto Rico Aqueduct and Sewer Authority Guánica Sewage Treatment 

Plant, is located on the eastern shore of the bay. Plans are being considered to add additional households to the WWTP 

inflow. It employs tertiary treatment, which removes a large portion of the nitrogen from the waste stream. A second, much 

smaller WWTP sits on the coast to the east of the bay. It treats waste from public facilities at a beach access and likely 

represents only minor nutrient inputs to the coastal system.
 

Agriculture in the watershed includes low density pasture land, a variety of crop lands and coffee farms (see further discussion in Chapter 1).
 

Objectives

The goals of this portion of the baseline assessment of Guánica Bay were to:
 

1.	 quantify magnitude and spatiotemporal variability of surface water nutrients in the bay and the offshore coral 

reef ecosystem; 

2.	 establish a baseline of nutrient conditions against which to measure changes in the future; and 

3.	 link observed concentrations of nutrients to hydrologic forcing factors and possible nutrient sources. 

methods 

Nutrient Sampling

Eighteen sites were randomly selected from six geographic strata (three sites per strata, Figure 5.1). From 2009 to 2012, 

each of these sites was visited monthly to collect surface water grab samples. Additionally, two targeted sites in the bay, 

mouth of Rio Loco (N31) and mouth of bay (N32), and three targeted riverine sites in the watershed were sampled: the 

southernmost site (N31) being close to the outflow point of the river into the bay, the westernmost site (N33) which is on 

the agricultural drainage canal upstream from where it joins the Rio Loco, and the northernmost site which is on the main 

stem of the Rio Loco (N34; Figure 5.1). The targeted sites were selected in order to capture nutrient signals at hydrologically important locations, i.e., mouth of river, mouth of bay, the drainage canal and the mainstem of the Rio Loco. Watershed sites were targeted rather than random due to logistical considerations regarding site access. 

1. NOAA/NOS/NCCOS

2. Department of Marine Sciences, University of Puerto Rico – Mayaguez,

3. Corresponding author: dave.whitall@noaa.gov 

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Nutrient samples were collected in high density polyethylene bottles from 0.1 m below 

the surface. At extremely shallow sites (e.g., 

riverine sites at lower flows), samples were 

taken at half the distance to the bottom. In 

this situation, care was taken to exclude 

sediment from the samples. Bottles were 

rinsed three times with site water prior to 

sampling. Nitrile or latex gloves were worn 

by field personnel to avoid contamination of 

the samples during handling. Samples were 

stored on ice, in the dark while in the field 

and frozen at -20°C upon returning to the 

lab and not thawed until immediately prior 

to analysis. Samples were not filtered so 

that total nutrient levels could be analyzed, 

rather than only dissolved levels. 

Analytical Methods Used for the 

Analysis of Nutrients in Water 

Nutrient laboratory analyses were performed at a contract lab (Geochemical and 

Environmental Research Group, Texas 

A&M University). Water samples were analyzed for a standard suite of nutrient analytes: nitrate (NO3

-

), nitrite (NO2

-

), orthophosphate (HPO4

=), ammonium (NH4

+), urea 

((NH2)2CO), total nitrogen and total phosphorus (Table 5.1). 

Nitrate and nitrite analyses were based on 

the methodology of Armstrong et al. (1967). 

Orthophosphate was measured using the 

methodology of Bernhardt and Wilhelms 

(1967) with the modification of hydrazine 

as reductant. Silicate determination was accomplished using the methods of Armstrong 

et al. (1967) using stannous chloride. Ammonium analysis was based on the method 

of Harwood and Kuhn (1970) using dichloro-isocyanurate as the oxidizer. Urea was 

measured using diacetyl-monoximine and 

themicarbozide. The total concentrations of 

nitrogen and phosphorus were determined 

after an initial decomposition step. This 

method involves persulfate oxidation while 

heating the sample in an autoclave (115°C, 20 minutes; Hansen and Koroleff, 1999). After oxidation of the samples, nutrient determination was conducted on the Technicon II analyzer for nitrate and orthophosphate. 

Analyte method 

detection 

Limit (μM) 

method 

detection 

limit (mg/l) 

standard 

Range (μM) 

standard Range 

(mg/l) 

NO3 

- 0.177 0.010 3.85 - 30.14 0.23 - 1.86 

NO2 

- 0.010 0.0004 0.09 - 0.72 0.006 - 0.033 

HPO4 

= 0.030 0.002 0.35 - 2.18 0.021 - 0.21 

HSIO3 

- 0.155 0.014 4.05 - 30.08 0.25 - 2.80 

NH4 

+ 0.070 0.001 0.42 - 3.44 0.026 - 0.062 

Urea 0.205 0.012 0.59 - 4.42 0.036 - 0.265 

Statistical Analysis of Data

Data were analyzed using JMP® statistical software. The data were first tested for normality using the Shapiro-Wilk test. 

Because the data were not normally distributed, non-parametric statistical tests were used; a Dunn’s multiple comparison 

test was used to examine differences between sites, seasons and years. Spearman’s rank correlation coefficient test 

was used to examine relationships between analytes. Because they were not randomly selected, targeted sites were not 

included in analyses of differences between strata, but were included in correlative analyses and in summary statistics 

because they help to characterize the overall status of the system. 

Figure 5.1. Map of sampling sites. 

Table 5.1. Details on analytical methods for nutrients. Units are expressed as mgN/L or mg-P/L. 

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Nutrients 

Results And disCussion 

Summary Statistics

Summary statistics (mean, median, maximum, minimum, standard deviation) for 

each analyte are presented in Table 5.2. 

These statistics are inclusive of the five 

targeted sites. These values are similar 

to what has been observed in other comparable studies in Puerto Rico (Table 5.3). 

Watershed sites presented in this study had 

higher concentrations than data collected 

for Jobos Bay and southwest Puerto Rico, 

but those studies did not include any sites 

in the watershed, so this is not surprising. 

Table 5.2. Summary statistics for nutrient analytes across all sites. Units are 

expressed as mg-N/L or mg-P/L. 

mean median stdev max min 

NO3 

-

+NO2 

- 0.14 0.01 0.32 3.68 0.00 

NH4 

+ 0.05 0.01 0.23 6.45 0.00 

Urea 0.01 0.00 0.02 0.42 0.00 

Total N 0.46 0.28 0.56 10.94 0.01 

HPO4 

= 0.05 0.01 0.11 1.48 0.00 

Total P 0.08 0.03 0.14 1.95 0.00 

Table 5.3. Comparison with other sites in Puerto Rico. Vieques data from Whitall et al., 2010; Jobos data from Whitall et al., 2011. Units 

are expressed as mg-N/L or mg-P/L. 

guánica Vieques jobos 

mean median stdev max mean stdev max mean stdev max 

NH4 

+ 0.05 0.01 0.23 6.45 0.00 0.00 0.01 No data No data No data 

Urea 0.01 0.00 0.02 0.42 0.01 0.00 0.03 No data No data No data 

Oxidized N 0.14 0.01 0.32 3.68 0.00 0.00 0.00 0.01 0.01 0.12 

Total N 0.46 0.28 0.56 10.94 0.13 0.23 2.77 No data No data No data 

HPO4 

= 0.05 0.01 0.11 1.48 0.00 0.00 0.01 0.01 0.01 0.17 

Total P 0.08 0.03 0.14 1.95 0.01 0.00 0.01 No data No data No data 

Spatial Patterns

Spatial patterns for mean and maximum 

values for each analyte are shown in Figure 

5.2 through 5.13. In general, data show a 

pattern of dilution, with the highest concentrations for all analytes occurring in the watershed and becoming diluted as they move 

into the bay, and further diluted offshore 

(Figures 5.14 through 5.16). This suggests 

that the watershed, rather than the near bay 

environment, is the primary source of nutrients to the system. Measurements of flux 

values of nutrients were beyond the scope 

of this study, but if there were strong sources of nutrients being discharged directly into 

the bay, this clear pattern of dilution shown 

by the concentration data would not be as 

well defined. One exception to this pattern 

of observations was for nitrate/nitrite which 

had a high maximum value observed near 

the WWTP. This elevated value occurred 

on one date in 2011, and appears to be an 

aberration, i.e. this was the only date during 

the study period that this occurred. It is not 

known what caused this spike, but it is possible that there was an event at the WWTP 

that caused a temporary spike in oxidized 

nitrogen outflow. 

Offshore nutrient patterns do not suggest a 

strong downstream (east to west) gradient 

as might be expected, with the prevailing 

current structure moving along shore from 

east to west. There were no significant differences among the three offshore strata (Dunn’s test, α=0.05). 

Figure 5.2. Oxidized nitrogen (nitrate plus nitrite as mg-N/L) mean concentrations. 

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116 

Figure 5.3. Oxidized nitrogen (nitrate plus nitrite as mg-N/L) maximum concentrations. 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Nutrients 

Figure 5.4. Ammonium mean concentrations (as mg-N/L). 

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118 

Figure 5.5. Ammonium maximum concentrations (as mg-N/L). 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Nutrients 

Figure 5.6. Urea mean concentrations (as mg-N/L). 

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120 

Figure 5.7. Urea maximum concentrations (as mg-N/L). 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Nutrients 

Figure 5.8. Total nitrogen mean concentrations (as mg-N/L). 

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122 

Figure 5.9. Total nitrogen maximum concentrations (as mg-N/L). 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Nutrients 

Figure 5.10. Orthophosphate mean concentrations (as mg-P/L). 

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124 

Figure 5.11. Orthophosphate maximum concentrations (as mg-P/L). 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Nutrients 

Figure 5.12. Total phosphorus mean concentrations (as mg-P/L). 

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126 

Figure 5.13. Total phosphorus maximum concentrations (as mg-P/L). 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Nutrients 

Figure 5.14. Total nitrogen and oxidized nitrogen (nitrate plus 

nitrite, as mg-N/L) means and standard deviations by geographic 

area. 

0 

0.2 

0.4 

0.6 

0.8 

1 

1.2 

1.4 

1.6 

1.8 

2 

Watershed Bay Offshore 

Total N 

NO3-+NO2­

mg-n/l 

Figure 5.15. Ammonium and urea means and standard deviations 

(as mg-N/L) by geographic area. 

0 

0.05 

0.1 

0.15 

0.2 

0.25 

0.3 

0.35 

Watershed Bay Offshore 

NH4+ 

Urea 

mg-n/l 

0 

0.05 

0.1 

0.15 

0.2 

0.25 

0.3 

0.35 

0.4 

0.45 

0.5 

Watershed Bay Offshore 

Total P 

HPO4= 

mg-P/l 

Figure 5.16. Total phosphorus and orthophosphate means and 

standard deviations (as mg-P/L) by geographic area. 

For every analyte except nitrate/nitrite, there were statistically significant differences between all individual bay strata and 

all individual offshore strata, as well as differences between the North Bay/Central Bay strata and the South Bay. In all 

cases the northern strata were higher than the southern strata (e.g., Central Bay is greater than South Bay). The majority 

of these statistical relationships were very strong (p<0.001). For nitrate/nitrite differences existed only between the North 

Bay and the South Bay and offshore strata, with the North Bay being higher. A matrix of statistical comparisons between 

strata is shown in Table 5.4. 

Temporal Patterns

There are statistically significant differences between the sampling years for all analytes. Seasonally, urea, ammonium 

and orthophosphate were all statistically higher during the rainy season than during the dry season (Wilcoxon test α=0.05). 

This is expected because, while oxidized nitrate percolates quickly to groundwater, urea, ammonia and phosphorus fluxes 

are driven more by surface water runoff, which is tightly linked to precipitation. 

Relationship Between Analytes

Spearman’s rank correlation coefficient test showed that, beyond analytes which are autocorrelated (e.g., ammonium and 

total nitrogen), ammonium, urea and orthophosphorus were significantly (α=0.05) and strongly (ρ>0.70) correlated with 

each other. This is not surprising because these nutrients are most strongly associated with runoff, as opposed to oxidized 

forms of nitrogen that tend to percolate to groundwater. 

Relationship with Precipitation

Because riverine flow values were not available, nutrient flux could not be calculated. However, nutrient concentrations 

may be compared to precipitation, as a proxy for flow. Relating precipitation (and by proxy overland flow and riverine 

inputs) to stream and marine nutrient data for Guánica is complicated by the large degree to which the hydrology of the 

system has been altered by humans. In addition to there being a time lag between when rains fall in the upper watershed 

and when nutrients are delivered to the bay, there are also lags due to the reservoirs in the upper watershed, and the 

diversion of water from the mainstem of the Rio Loco to the Lajas valley (see further discussion in Chapter 1). 

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Nutrients 

Table 5.4. Results of Dunn Test (α=0.05) comparing nutrient concentrations between strata. 

Analyte strata strata p Value 

HPO4= Offshore East Bay North < 0.001 

HPO4= Offshore West Bay North < 0.001 

HPO4= Offshore Central Bay North < 0.001 

HPO4= Offshore East Bay Central < 0.001 

HPO4= Offshore West Bay Central < 0.001 

HPO4= Offshore Central Bay Central < 0.001 

HPO4= Offshore East Bay South < 0.001 

HPO4= Offshore West Bay South < 0.001 

HPO4= Offshore Central Bay South < 0.001 

HPO4= Bay South Bay North < 0.001 

HPO4= Bay South Bay Central 0.0028 

Total P Offshore East Bay North < 0.001 

Total P Offshore Central Bay North < 0.001 

Total P Offshore West Bay North < 0.001 

Total P Offshore East Bay Central < 0.001 

Total P Offshore Central Bay Central < 0.001 

Total P Offshore West Bay Central < 0.001 

Total P Offshore East Bay South < 0.001 

Total P Offshore Central Bay South < 0.001 

Total P Bay South Bay North < 0.001 

Total P Offshore West Bay South < 0.001 

Total P Bay South Bay Central 0.0010 

NH4+ Offshore West Bay North < 0.001 

NH4+ Offshore Central Bay North < 0.001 

NH4+ Offshore East Bay North < 0.001 

NH4+ Offshore West Bay Central < 0.001 

NH4+ Offshore Central Bay Central < 0.001 

NH4+ Offshore East Bay Central < 0.001 

NH4+ Bay South Bay North < 0.001 

NH4+ Offshore West Bay South < 0.001 

NH4+ Offshore Central Bay South < 0.001 

NH4+ Offshore East Bay South < 0.001 

NH4+ Bay South Bay Central < 0.001 

NO3-+NO2­ Offshore West Bay North < 0.001 

NO3-+NO2­ Offshore East Bay North 0.0013 

NO3-+NO2­ Bay South Bay North 0.0019 

NO3-+NO2­ Offshore Central Bay North 0.0020 

Total N Offshore Central Bay North < 0.001 

Total N Offshore East Bay North < 0.001 

Total N Offshore West Bay North < 0.001 

Total N Offshore Central Bay Central < 0.001 

Total N Offshore East Bay Central < 0.001 

Total N Offshore West Bay Central < 0.001 

Total N Offshore Central Bay South < 0.001 

Total N Bay South Bay North < 0.001 

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Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Nutrients 

Table 5.4 (continued). Results of Dunn Test (α=0.05) comparing nutrient concentrations between strata. 

Analyte strata strata p Value 

Total N Offshore East Bay South < 0.001 

Total N Offshore West Bay South < 0.001 

Total N Bay South Bay Central < 0.001 

Urea Offshore Central Bay North < 0.001 

Urea Offshore East Bay North < 0.001 

Urea Offshore West Bay North < 0.001 

Urea Offshore Central Bay Central < 0.001 

Urea Offshore East Bay Central < 0.001 

Urea Offshore West Bay Central < 0.001 

Urea Bay South Bay North < 0.001 

Urea Offshore Central Bay South < 0.001 

Urea Bay South Bay Central 0.0016 

Urea Offshore East Bay South 0.0120 

Urea Offshore West Bay South 0.0139 

Urea Bay North Bay Central 0.0312 

In order to minimize the confounding nature of the altered hydrology, a coastal rain gauge was desirable for comparison 

with nutrient concentrations. The coastal rain gauge with the most complete data set during the study period was located 

at the University of Puerto Rico Marine Lab in Lajas (UPR, 2013). A suite of time series graphs are presented in Appendix 

C. A representative graph for each analyte from each stratum is presented (42 graphs total). In general, the coastal precipitation values track relatively well with nutrient concentrations. While not all large precipitation events result in a nutrient spike, it is rare to see a nutrient spike without a corresponding precipitation event. One notable example of such an 

exception occurred on 17 March 2011, when an anomalously high nitrate+nitrite value was observed at site N23, which is 

located near the WWTP (Appendix C, Figure C.25). This concentration was an order of magnitude higher than was what 

typically measured at that site, and while it is unclear what caused this spike, it is possible that it is related to some sort of 

incident at the WWTP. This was the only sampling date that demonstrated a high value at this site. Event based sampling 

(i.e. storm flow sampling) in future studies would further clarify the relationship between precipitation events and nutrient 

concentrations. 

Impact to Coral Reefs

Lapointe (1997) previously proposed nutrient threshold values for coral reefs. This previous work postulated that for reefs 

in Florida, 0.014 mg/L inorganic nitrogen (DIN) and 0.031 mg/L soluble reactive phosphorus (SRP) were the thresholds 

above which coral reefs are impacted adversely. In the offshore waters, where coral reefs currently exist, inorganic phosphorus values exceeded this threshold on two sampling dates: 10 July 2009, at sites N12 and N27, and on 9 September 

2009 at site N29. This suggests that coral reefs in this system are rarely exposed to SRP values that would be indicative 

of problems with macroalgae. DIN, on the other hand, exceeded the proposed threshold at the offshore sites for approximately 10% of the data points. There were 88 data points (out of 878) with a DIN value of greater than 0.014 mg/L. 

Every offshore site had at least one sampling date with a DIN concentration greater than 0.014 mg/L. Sites in the central 

stratum had more frequent exceedances, with site N27 having the most frequent (18 times) high DIN. A similar number 

of average monthly exceedances occurred during the wet and the dry seasons. This may be due to a source which does 

not vary much through time (e.g., groundwater discharge) or may be confounded by other seasonal forcing factors (e.g., 

physical oceanography). Regardless, these high DIN values suggest that corals may be at risk from high nutrient levels. 

Implications for Watershed Management

The observed patterns in nutrient concentrations suggest that lower watershed point sources (i.e., the WWTP) are not the 

dominant source of nutrients to the system. This is not to say that the WWTP isn’t an important source of nutrients, but 

it needs to be considered along with sources of nitrogen from farther up in the watershed. Agricultural fertilizer use and 

houses with septic systems are likely other major sources of nutrients. Nitrogen may also be introduced into the system 

by natural biological nitrogen fixation or by anthropogenically enhanced atmospheric nitrogen deposition. Because nutrients, especially nitrogen, are multi-source pollutants, a comprehensive nutrient management strategy that targets multiple sources of nutrient inputs is required. Additional data, including additional spatial coverage and flow measurements, 

would shed additional light on nutrient dynamics in this system. 

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Nutrients 

ConClusions 

These data demonstrate that nutrients are reaching the bay via surface runoff and/or groundwater discharge. These pathways of transport may be of concern to nutrient sensitive offshore coral reef ecosystems. 

These data make up part of a larger baseline assessment of this system (see Chapters 2, 3 and 4 of this report), which will 

be used to evaluate the planning for and efficacy of implementation of watershed best management practices. The water 

quality parameters discussed here will likely respond very quickly to changes in the watershed, making them especially 

useful for documenting short term changes to the system. 

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Nutrients 

RefeRenCes 

Armstrong, F. A. J., C. R. Stearns and J. D. H. Strickland. 1967. The measurement of upwelling and subsequent biological processes 

by means of the Technicon AutoAnalyzerTM and associated equipment. Deep-Sea Res. 14(3): 381-389. 

Bell, P.R.F. 1992. Eutrophication and coral reefs: Some examples in the Great Barrier Reef lagoon. Water Research 26: 553-568. 

Bernhardt, H. and A. Wilhelms. 1967. The continuous determination of low level iron, soluble phosphate and total phosphate with the 

Autoanalyzer. Technicon Symposium. 

Bricker, S., B. Longstaff, W. Dennison, A. Jones, K. Boicourt, C. Wicks and J. Woerner. 2007. Effects of Nutrient Enrichment in the Nation’s Estuaries: A Decade of Change, National Estuarine Eutrophication Assessment Update. NOAA Coastal Ocean Program Decision 

Analysis Series No. 26. National Centers for Coastal Ocean Science, Silver Spring, MD. 322 pp. 

Galloway J.N., J.D. Aber, J.W. Erisman, S.P. Seitzinger, R.H. Howarth, E.B. Cowling and B.J. Cosby. 2003. The nitrogen cascade. 

BioScience 53: 341-356. 

Hansen, H.P. and F. Koroleff. 1999. Determination of nutrients. In:Grasshoff, K., K. Kremling, M. Ehrhardt (eds.). Methods of Seawater 

Analysis, 3rd ed. Wiley-VCH, Weinheim, ISBN:3-527-29589-5pp. 159– 228. 

Harrison, P.L. and S. Ward. 2001. Elevated levels of nitrogen and phosphorus reduce fertilisation success of gametes from scleractinian reef corals. Marine Biology 139: 1057-1068. 

Harwood, J. E. and A. L. Kuhn (1970). “A colorimetric method for ammonia in natural waters.” Water Research 4: 805 - 811. 

Lapointe, B.E. 1997. Nutrient thresholds for bottom-up control of macroalgal blooms on coral reefs in Jamaica and southeast Florida. 

Limnol. Ocean 42: 1119-1131. 

Marubini, F. and P.S. Davies. 1996. Nitrate increases zooxanthellae population density and reduces skeletogenesis in corals. Marine 

Biology 127: 319-328. 

Mathews, L.G, F.R. Homans and K.W. Easter. 2002. Estimating the benefits of phosphorus pollution reductions: An application in the 

Minnesota River. Journal of the American Water Resources Association 38: 1217-1223. 

McCook, L.J. 1999. Macroalgae, nutrients and phase shifts on coral reefs: scientific issues and management consequences for the 

Great Barrier Reef. Coral Reefs 18: 357-367. 

University of Puerto Rico. 2013. Bio-optical Oceangraphy Laboratory Weather Dataset. http://bio-optics.uprm.edu/weather.html Accessed 8/19/2013. 

Whitall, D.R., A.L. Mason, A.S. Pait, V Ransibrahmanakul and J.D. Christensen. 2010. Characterization of Spatial and Temporal Nutrient Dynamics. pp. 151-168. In: Bauer and Kendall (eds.), An Ecological Characterization of the Marine Resources of Vieques, Puerto 

Rico Part II: Field Studies of Habitats, Nutrients, Contaminants, Fish, and Benthic Communities. NOAA Technical Memorandum NOS 

NCCOS 110. Silver Spring, MD. 174 pp. 

Whitall, D.R., B.M. Costa, L.J. Bauer, A. Dieppa, and S.D. Hile (eds.). 2011. A Baseline Assessment of the Ecological Resources of 

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131 

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133 Integration and Conclusions 

Chapter 6: Conclusions 

David Whitall1 and Laurie Bauer1,2 

This study represents an interdisciplinary data set that enhances our understanding of the ecosystems in and around 

Guánica Bay, Puerto Rico. These data will serve as a useful baseline against which to measure future change. Change in 

a system, including assessment of management efficacy, cannot be measured without this type of baseline study. Different environmental parameters have the potential to change at different rates. For example, water quality may change in 

response to management activities rather quickly (on the order of weeks to months), whereas, metrics of coral reef health 

(e.g., percent live coral) may respond much more slowly (years to decades). Future monitoring and assessments need to 

take this into account in order to adequately track change. 

While coral cover was generally low across the entire study region, there is some evidence that the Guánica study region 

is more degraded that the La Parguera region to the west. Percent cover of hard corals, gorgonians and seagrass were 

higher in the La Parguera study area compared to Guánica. Fish community metrics were generally similar between the 

two regions, although there were some differences in species and family composition. It is not well known how sediment, 

nutrients and toxins are affecting coral and fish communities, and understanding these cause and effect relationships are 

critical to effective management and restoration practices. It is possible that distance from Guánica Bay, which is fairly 

polluted, may partially explain these differences. 

Numerous analytes (total chlordane, total DDT, total PAHs, total PCBs, arsenic, chromium, copper, mercury, nickel and 

zinc) were measured at levels in sediments that suggest possible toxicity to benthic infauna. Several analytes (PCBs, 

nickel, chromium, chlordane) were extremely high compared to values measured elsewhere in the U.S. Many of these 

pollutants were detected in coral tissues, although at lower concentrations than observed in the sediments. Because contaminant threshold values do not exist for coral, it is unclear what effect the observed contaminant levels might have on 

coral health. Although the highest level of contamination was observed inside the bay (i.e., away from the reefs), the mangrove areas around the bay are important nursery habitats for a variety of fish species. Future studies should consider fish 

tissue contaminants to assess whether there is an ecological or seafood safety issue related to contaminants in the bay. 

Sediment trap accumulation rates are spatiotemporally variable, with accumulated sediment composition (i.e., terrigenous versus carbonate) being relatively uniform. Sediment re-suspension is likely very important in this system and while 

Guánica Bay is likely an important sediment source, other up current sources may be important as well. 

Surface water nutrient values measured in the study area were similar to values observed elsewhere in the coastal waters 

of Puerto Rico. In general, nutrient concentrations were highest in the watershed, and concentrations decreased with dilution into the bay and offshore. Nutrient concentrations track fairly well with precipitation patterns, with higher phosphorus, 

ammonium and urea concentrations during the wet season. In offshore waters, phosphorus rarely exceeded previously 

proposed coral health thresholds; whereas, nitrogen exceeded thresholds 10% of the time. 

Although there is no singular stressor or response variable that captures the relationship between pollution and ecosystem health for this system, the preponderance of evidence presented in this report suggests that this system is experiencing anthropogenic stress, which may be resulting in coral decline. 

This suite of environmental data (biological and stressors) represent an important baseline against which to measure 

future change, such as improvements due to watershed restoration, or degradation due to further development in the 

area. Further monitoring and assessments are needed in order to detect changes in the ecosystem over a variety of time 

scales ranging from relatively short-term responses in sediment loading, to potentially decadal-long recovery processes 

for reef systems. 

1. NOAA/NOS/NCCOS COAST

2. CSS-Dynamac, Fairfax, VA 

Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Appendix A

Appendix A 

Table A.1. Mean species site frequency, density, and biomass for fish species observed within the Guánica study area in the 2010 

survey. 

species Common name family trophic 

group 

% of 

surveys 

mean 

density (se) 

mean 

biomass (se) 

Abudefduf saxatilis Sergeant major Pomacentridae I 11% 0.27 (0.15) 10.37 (6.17) 

Acanthurus bahianus Ocean surgeonfish Acanthuridae H 39% 3.08 (0.48) 122.86 (29.85) 

Acanthurus chirurgus Doctorfish Acanthuridae H 11% 0.49 (0.24) 19.93 (8.09) 

Acanthurus coeruleus Blue tang Acanthuridae H 30% 1 (0.29) 125.76 (45.16) 

Anisotremus 

virginicus 

Porkfish Haemulidae I 10% 0.28 (0.17) 76.62 (58.44) 

Archosargus

rhomboidalis 

Sea bream Sparidae H 7% 0.14 (0.14) 28.29 (28.16) 

Aulostomus 

maculatus 

Trumpetfish Aulostomidae P 5% 0.05 (0.03) 6.58 (4.59) 

Balistes vetula Queen triggerfish Balistidae I 13% 0.24 (0.08) 160.15 (63.17) 

Bathygobious 

soporator 

Frillfin goby Gobiidae I 2% 0.00 (0.00) 0.00 (0.00) 

Belonidae sp. Needlefish family sp. Belonidae P 5% 0.00 (0.00) 0.00 (0.00) 

Bodianus rufus Spanish hogfish Labridae I 7% 0.1 (0.05) 11.22 (6.79) 

Calamus calamus Saucereye porgy Sparidae I 10% 0.12 (0.05) 17.36 (7.27) 

Cantherhines 

macrocerus 

American whitespotted

filefish 

Monacanthidae I 2% 0.02 (0.02) 1.85 (1.86) 

Cantherhines pullus Orangespotted filefish Monacanthidae I 3% 0.04 (0.02) 1.65 (1.15) 

Canthigaster rostrata Sharpnose puffer Tetraodontidae I 20% 0.33 (0.09) 2.44 (0.86) 

Carangoides ruber Bar jack Carangidae P 11% 1.04 (0.82) 18.26 (14.06) 

Caranx crysos Blue runner Carangidae P 5% 0.29 (0.2) 104.37 (75.97) 

Caranx latus Horse-eye jack Carangidae P 2% 0.00 (0.00) 0.44 (0.44) 

Caranx sp. Jack sp. Carangidae P 2% 0.1 (0.1) 597.46 (598.23) 

Cephalopholis 

cruentata 

Graysby Serranidae P 11% 0.14 (0.06) 8.52 (4.96) 

Cephalopholis fulva Coney Serranidae I 15% 0.41 (0.12) 37.02 (12.1) 

Chaetodon 

capistratus 

Foureye butterflyfish Chaetodontidae I 44% 1.14 (0.21) 25.48 (5.23) 

Chaetodon ocellatus Spotfin butterflyfish Chaetodontidae I 3% 0.05 (0.04) 4.69 (3.31) 

Chaetodon 

sedentarius 

Reef butterflyfish Chaetodontidae I 2% 0.02 (0.02) 0.07 (0.07) 

Chaetodon striatus Banded butterflyfish Chaetodontidae I 25% 0.55 (0.11) 29.66 (8.9) 

Chromis cyanea Blue chromis Pomacentridae PL 8% 1.58 (0.76) 4.16 (2.07) 

Chromis multilineata Brown chromis Pomacentridae I 2% 0.07 (0.07) 0.33 (0.33) 

Clupeidae sp. Herring family sp. Clupeidae PL 7% 0.24 (0.12) 0.01 (0.01) 

Coryphopterus dicrus Colon goby Gobiidae I 3% 0.18 (0.15) 0.23 (0.17) 

Coryphopterus

glaucofraenum 

Bridled goby Gobiidae I 18% 0.74 (0.32) 1.65 (0.66) 

Cosmocampus

elucens 

Shortfin pipefish Syngnathidae PL 3% 0.04 (0.03) 0.15 (0.11) 

Cryptotomus roseus Bluelip parrotfish Scaridae H 8% 0.31 (0.19) 0.77 (0.41) 

Ctenogobius

saepepallens 

Dash goby Gobiidae I 2% 0.02 (0.02) 0.06 (0.06) 

Dasyatis americana Southern stingray Dasyatidae I 2% 0.02 (0.02) 137.41 (137.11) 

Elacatinus evelynae Sharknose goby Gobiidae I 10% 0.22 (0.10) 0.38 (0.14) 

135 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Appendix A

Table A.1 (continued). Mean species site frequency, density, and biomass for fish species observed within the Guánica study area in 

the 2010 survey. 

species Common name family trophic 

group 

% of 

surveys 

mean 

density (se) 

mean 

biomass (se) 

Epinephelus

adscensionis 

Rock hind Serranidae I 2% 0.05 (0.05) 0.75 (0.75) 

Epinephelus guttatus Red hind Serranidae I 5% 0.05 (0.03) 7.02 (4.58) 

Equetus punctatus Spotted drum Sciaenidae I 2% 0.02 (0.02) 0.07 (0.07) 

Eucinostomus gula Silver jenny Gerreidae I 8% 0.55 (0.34) 9.6 (5.93) 

Eucinostomus 

melanopterus 

Flagfin mojarra Gerreidae I 11% 0.33 (0.24) 0.93 (0.76) 

Gerres cinereus Yellowfin mojarra Gerreidae I 15% 0.10 (0.07) 0.59 (0.37) 

Ginglymostoma

cirratum 

Nurse shark Ginglymostomatidae I 2% 0.02 (0.02) 0.05 (0.05) 

Gnatholepis

thompsoni 

Goldspot goby Gobiidae H 15% 0.83 (0.62) 1.42 (0.53) 

Gramma loreto Fairy basslet Grammatidae I 2% 0.12 (0.12) 0.09 (0.10) 

Haemulon 

aurolineatum 

Tomtate Haemulidae I 5% 0.42 (0.3) 38.6 (33.48) 

Haemulon 

chrysargyreum 

Haemulon flavolineatum 

Smallmouth grunt 

French grunt 

Haemulidae 

Haemulidae 

I 

I 

3% 

39% 

0.04 (0.03) 

1.01 (0.52) 

0.73 (0.67) 

139.02 (104.99) 

Haemulon parra Sailors choice Haemulidae I 3% 0.00 (0.00) 0.02 (0.02) 

Haemulon plumierii White grunt Haemulidae I 21% 0.28 (0.08) 60.32 (28.19) 

Haemulon sciurus Bluestriped grunt Haemulidae I 20% 0.56 (0.29) 145.58 (78.78) 

Haemulon sp. Grunt sp. Haemulidae I 11% 3.39 (1.85) 7.21 (5.86) 

Halichoeres bivittatus Slippery dick Labridae I 44% 3.44 (0.73) 17.8 (4.2) 

Halichoeres 

cyanocephalus 

Yellowcheek 

wrasse 

Labridae P 2% 0.02 (0.02) 0.15 (0.15) 

Halichoeres garnoti Yellowhead 

wrasse 

Labridae I 41% 3.27 (0.72) 24.92 (6.05) 

Halichoeres 

maculipinna 

Clown wrasse Labridae I 16% 0.42 (0.14) 2.87 (1.34) 

Halichoeres poeyi Blackear wrasse Labridae I 13% 0.64 (0.3) 2.32 (0.96) 

Halichoeres radiatus Puddingwife Labridae I 7% 0.07 (0.03) 0.53 (0.26) 

Heteroconger

longissimus 

Brown garden eel Congridae PL 3% 0.57 (0.42) 19.28 (18.75) 

Holacanthus ciliaris Queen angelfish Pomacanthidae I 7% 0.07 (0.03) 21.05 (11.18) 

Holacanthus tricolor Rock beauty Pomacanthidae I 5% 0.05 (0.03) 2.19 (1.47) 

Holocentrus 

adscensionis 

Squirrelfish Holocentridae I 23% 0.48 (0.13) 43.75 (16.69) 

Holocentrus rufus Longspine

squirrelfish 

Holocentridae I 16% 0.41 (0.15) 33.62 (14.35) 

Hypoplectrus chlorurus Yellowtail hamlet Serranidae I 2% 0.02 (0.02) 0.32 (0.32) 

Jenkinsia sp. Herring species Clupeidae PL 8% 2.09 (1.50) 0.10 (0.07) 

Lachnolaimus maximus Hogfish Labridae I 2% 0.02 (0.02) 2.14 (2.14) 

Lactophrys triqueter 

Lutjanus apodus 

Smooth trunkfish 

Schoolmaster 

Ostraciidae 

Lutjanidae 

I 

P 

5% 

21% 

0.05 (0.03) 

0.16 (0.08) 

5.31 (3.37) 

7.41 (3.42) 

Lutjanus cyanopterus Cubera snapper Lutjanidae P 3% 0.02 (0.02) 46.1 (46.09) 

Lutjanus griseus Gray snapper Lutjanidae I 11% 0.00 (0.00) 0.69 (0.33) 

Lutjanus jocu Dog snapper Lutjanidae P 2% 0.00 (0.00) 0.01 (0.01) 

Lutjanus mahogoni Mahogany 

snapper 

Lutjanidae P 5% 0.05 (0.03) 5.26 (3.84) 

136 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Appendix A

Table A.1 (continued). Mean species site frequency, density, and biomass for fish species observed within the Guánica study area in 

the 2010 survey. 

species Common name family trophic 

group 

% of 

surveys 

mean 

density (se) 

mean 

biomass (se) 

Lutjanus synagris Lane snapper Lutjanidae I 26% 1.28 (0.68) 11.3 (5.52) 

Malacanthus plumieri Sand tilefish Malacanthidae I 8% 0.1 (0.05) 28.18 (16.55) 

Malacoctenus 

triangulatus 

Saddled blenny Labrisomidae I 11% 0.12 (0.04) 0.46 (0.17) 

Melichthys niger Black durgon Balistidae H 16% 1.34 (0.78) 543.86 (466.47) 

Microgobius carri Seminole goby Gobiidae H 2% 0.03 (0.03) 0.06 (0.06) 

Microgobius signatus Microgobius signatus Gobiidae H 2% 0.07 (0.07) 0.09 (0.09) 

Microspathodon

chrysurus 

Yellowtail 

damselfish 

Pomacentridae H 5% 0.2 (0.15) 6 (3.93) 

Monacanthus ciliatus Fringed filefish Monacanthidae H 2% 0.02 (0.02) 0.05 (0.06) 

Monacanthus tuckeri Slender filefish Monacanthidae PL 2% 0.02 (0.02) 0.43 (0.43) 

Mulloidichthys

martinicus 

Yellow goatfish Mullidae I 3% 0.62 (0.46) 158.05 (112.56) 

Myripristis jacobus Blackbar soldierfish Holocentridae I 8% 0.31 (0.17) 40.98 (22.4) 

Nes longus Orangespotted goby Gobiidae H 7% 1.37 (0.72) 3.77 (1.9) 

Ocyurus chrysurus Yellowtail snapper Lutjanidae PL 26% 0.79 (0.24) 66.77 (29.02) 

Ophioblennius

macclurei 

Redlip blenny Blenniidae H 5% 0.27 (0.21) 1 (0.72) 

Opistognathus aurifrons Yellowhead jawfish Opistognathidae PL 5% 0.3 (0.2) 1.57 (0.9) 

Pareques acuminatus Highhat Sciaenidae I 3% 0.03 (0.02) 1.56 (1.41) 

Pomacanthus arcuatus Gray angelfish Pomacanthidae I 7% 0.17 (0.08) 98.32 (49.59) 

Pomacanthus paru French angelfish Pomacanthidae I 2% 0.02 (0.02) 0.09 (0.09) 

Pseudupeneus

maculatus 

Spotted goatfish Mullidae I 5% 0.05 (0.03) 3.61 (2.26) 

Ptereleotris helenae Hovering goby Microdesmidae PL 3% 0.16 (0.14) 0.16 (0.12) 

Pterois volitans Red lionfish Scorpaenidae P 2% 0.02 (0.02) 2.27 (2.27) 

Rypticus saponaceus Greater soapfish Serranidae I 2% 0.02 (0.02) 1.55 (1.55) 

Scarus iseri Striped parrotfish Scaridae H 26% 0.92 (0.29) 15.31 (8.92) 

Scarus taeniopterus Princess parrotfish Scaridae H 16% 1.98 (1) 84.02 (36.58) 

Scarus vetula Queen parrotfish Scaridae H 2% 0.02 (0.02) 3.73 (3.72) 

Scorpaena plumieri 

Serranus baldwini 

Spotted scorpionfish 

Lantern bass 

Scorpaenidae 

Serranidae 

I 

P 

2% 

15% 

0.02 (0.02) 

0.49 (0.2) 

2.11 (2.11) 

1.71 (0.82) 

Serranus tabacarius Tobaccofish Serranidae P 5% 0.06 (0.03) 0.38 (0.22) 

Serranus tigrinus Harlequin bass Serranidae I 21% 1.05 (0.68) 2.77 (0.82) 

Serranus tortugarum Chalk bass Serranidae PL 8% 0.79 (0.41) 0.77 (0.36) 

Sparisoma atomarium Greenblotch parrotfish Scaridae H 7% 0.09 (0.05) 0.52 (0.29) 

Sparisoma

aurofrenatum 

Redband parrotfish Scaridae H 49% 3.1 (0.34) 72.32 (15.26) 

Sparisoma radians Bucktooth parrotfish Scaridae H 13% 0.45 (0.24) 0.96 (0.58) 

Sparisoma rubripinne Yellowtail parrotfish Scaridae H 3% 0.04 (0.03) 3.77 (2.61) 

Sparisoma sp. Parrotfish sp. Scaridae H 3% 0.05 (0.05) 0.42 (0.42) 

Sparisoma viride Stoplight parrotfish Scaridae H 28% 0.5 (0.12) 89.48 (32.75) 

Sphoeroides

testudineus 

Checkered puffer Tetraodontidae I 3% 0.00 (0.00) 0.06 (0.05) 

Sphyraena barracuda Great barracuda Sphyraenidae P 20% 0.07 (0.03) 402.29 (333.89) 

137 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Appendix A

Table A.1 (continued). Mean species site frequency, density, and biomass for fish species observed within the Guánica study area in 

the 2010 survey. 

species Common name family trophic 

group 

% of 

surveys 

mean 

density (se) 

mean 

biomass (se) 

Stegastes diencaeus Longfin damselfish Pomacentridae H 7% 0.02 (0.02) 0.08 (0.06) 

Stegastes leucostictus Beaugregory Pomacentridae I 18% 0.18 (0.08) 1.09 (0.5) 

Stegastes partitus Bicolor damselfish Pomacentridae H 44% 11.02 (1.45) 32.98 (11) 

Stegastes planifrons Threespot damselfish Pomacentridae I 7% 0.43 (0.41) 3.73 (3.48) 

Stegastes variabilis Cocoa damselfish Pomacentridae H 2% 0.02 (0.02) 0.23 (0.23) 

Synodus intermedius Sand diver Synodontidae P 2% 0.02 (0.02) 0.13 (0.13) 

Thalassoma bifasciatum Bluehead Labridae I 39% 13.6 (2.44) 22.87 (9.93) 

Xyrichtys martinicensis Rosy razorfish Labridae I 5% 0.19 (0.13) 0.74 (0.58) 

Xyrichtys novacula Pearly razorFish Labridae I 2% 0.07 (0.07) 0.13 (0.13) 

Xyrichtys splendens Green razorfish Labridae I 21% 1.27 (0.47) 4.83 (1.84) 

138 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Appendix A

Table A.2. Mean species site frequency, density, and biomass for fish species observed within the La Parguera study area in the August 2008-2010 surveys. 

species Common name family trophic 

group 

% of 

surveys 

mean 

density (se) 

mean 

biomass (se) 

Abudefduf saxatilis Sergeant major Pomacentridae I 7% 0.02 (0.01) 0.37 (0.29) 

Abudefduf taurus Night sergeant Pomacentridae H 1% 0.01 (0.01) 0.24 (0.24) 

Acanthemblemaria 

maria 

Secretary blenny Chaenopsidae PL 1% 0.01 (0.01) <0.01 (<0.01) 

Acanthemblemaria 

sp. 

Tube Blenny sp. Chaenopsidae PL 1% 0.01 (0.01) <0.01 (<0.01) 

Acanthostracion 

quadricornis 

Scrawled cowfish Ostraciidae I 1% 0.01 (0.01) 0.04 (0.04) 

Acanthurus bahianus Ocean surgeonfish Acanthuridae H 43% 2.48 (0.3) 148.7 (18.29) 

Acanthurus chirurgus Doctorfish Acanthuridae H 12% 0.5 (0.14) 23.37 (6.02) 

Acanthurus coeruleus Blue tang Acanthuridae H 27% 1.53 (0.53) 87.63 (32.03) 

Amblycirrhitus pinos Redspotted hawkfish Cirrhitidae I 1% 0.01 (0.01) 0.01 (0.01) 

Anisotremus 

virginicus 

Porkfish Haemulidae I 6% 0.04 (0.02) 3.22 (1.78) 

Archosargus

rhomboidalis 

Sea bream Sparidae H 5% <0.01 (<0.01) 0.23 (0.12) 

Atherinomorus sp. Silverside sp. Atherinidae H 4% 130.91 (121.98) 34.55 (32.19) 

Aulostomus 

maculatus 

Trumpetfish Aulostomidae P 3% 0.03 (0.01) 1.78 (0.92) 

Balistes vetula Queen triggerfish Balistidae I 12% 0.15 (0.03) 110.02 (26.14) 

Bodianus rufus Spanish hogfish Labridae I 1% 0.01 (0.01) 1.07 (1.03) 

Bollmannia 

boqueronensis 

White-eye goby Gobiidae H 3% 0.07 (0.03) 0.34 (0.15) 

Bothus lunatus Platefish Bothidae P 1% 0.01 (0.01) 0.07 (0.07) 

Calamus calamus Saucereye porgy Sparidae I 4% 0.06 (0.02) 6.59 (2.68) 

Calamus penna Sheepshead porgy Sparidae I 1% 0.01 (0.01) 0.54 (0.55) 

Calamus pennatula Pluma porgy Sparidae I 3% 0.04 (0.02) 7.69 (3.78) 

Calamus sp. Porgy sp. Sparidae I 1% 0.01 (0.01) 0.65 (0.65) 

Cantherhines pullus Orangespotted filefish Monacanthidae I 1% 0.01 (0.01) 0.55 (0.55) 

Canthigaster rostrata Sharpnose puffer Tetraodontidae I 27% 0.42 (0.06) 0.76 (0.15) 

Carangoides ruber Bar jack Carangidae P 10% 1.05 (0.44) 26.85 (15.97) 

Caranx crysos Blue runner Carangidae P 3% 0.44 (0.27) 262.9 (243.54) 

Cephalopholis 

cruentata 

Graysby Serranidae P 13% 0.19 (0.05) 11.26 (3.49) 

Cephalopholis fulva Coney Serranidae I 5% 0.06 (0.02) 7.89 (3.8) 

Chaenopsis limbaughi Yellowface pikeblenny Chaenopsidae I 1% 0.01 (0.01) <0.01 (<0.01) 

Chaenopsis sp. Pikeblenny sp. Chaenopsidae I 1% 0.01 (0.01) 0.08 (0.06) 

Chaetodon 

capistratus 

Foureye butterflyfish Chaetodontidae I 49% 1.45 (0.13) 21.19 (2.02) 

Chaetodon ocellatus Spotfin butterflyfish Chaetodontidae I 1% 0.01 (0.01) 0.02 (0.02) 

Chaetodon striatus Banded butterflyfish Chaetodontidae I 4% 0.07 (0.03) 1.4 (0.56) 

Chromis cyanea Blue chromis Pomacentridae PL 12% 0.95 (0.26) 2.17 (0.57) 

Chromis multilineata Brown chromis Pomacentridae I 2% 0.1 (0.08) 0.42 (0.34) 

Clepticus parrae Creole wrasse Labridae PL 4% 0.7 (0.34) 62.32 (48.12) 

Clupeidae sp. Clupidae family sp. Clupeidae PL 3% 0.63 (0.36) 0.03 (0.02) 

Coryphopterus dicrus Colon goby Gobiidae I 10% 0.21 (0.06) 0.32 (0.09) 

Coryphopterus

eidolon 

Pallid goby Gobiidae H 2% 0.06 (0.04) 0.08 (0.05) 

139 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Appendix A

Table A.2 (continued). Mean species site frequency, density, and biomass for fish species observed within the La Parguera study area 

in the August 2008-2010 surveys. 

species Common name family trophic 

group 

% of 

surveys 

mean 

density (se) 

mean 

biomass (se) 

Coryphopterus 

glaucofraenum 

Bridled goby Gobiidae I 30% 2.16 (0.52) 1.89 (0.39) 

Coryphopterus 

lipernes 

Peppermint goby Gobiidae I 3% 0.09 (0.05) 0.09 (0.04) 

Coryphopterus 

personatus/hyalinus 

Masked/glass goby Gobiidae I 10% 2.17 (0.81) 1.62 (0.56) 

Cryptotomus roseus Bluelip parrotfish Scaridae H 13% 0.45 (0.13) 1.58 (0.59) 

Ctenogobius 

saepepallens 

Dash goby Gobiidae I 3% 0.09 (0.04) 0.07 (0.04) 

Decapterus macarellus Mackerel scad Carangidae PL 2% 1.04 (0.62) 22.98 (12.11) 

Decapterus sp. Scad sp. Carangidae PL 1% 0.07 (0.07) 1.12 (1.12) 

Diplectrum bivittatum Dwarf sand perch Serranidae P 1% 0.01 (0.01) 0.02 (0.02) 

Echeneis naucrates Sharksucker Echeneidae PL 1% 0.03 (0.02) 1.79 (1.52) 

Elacatinus chancei Shortstripe goby Gobiidae I 1% 0.01 (0.01) <0.01 (<0.01) 

Elacatinus dilepis 

Elacatinus evelynae 

Orangesided goby 

Sharknose goby 

Gobiidae 

Gobiidae 

I 

I 

1% 

16% 

0.02 (0.02) 

0.33 (0.06) 

0.02 (0.02) 

0.2 (0.05) 

Epinephelus guttatus Red hind Serranidae I 4% 0.05 (0.02) 9.48 (3.94) 

Epinephelus striatus Nassau grouper Serranidae P 1% 0.01 (0.01) 5.32 (5.32) 

Equetus punctatus Spotted drum Sciaenidae I 1% 0.02 (0.02) 0.1 (0.09) 

Eucinostomus gula Silver jenny Gerreidae I 2% 0.02 (0.02) 0.78 (0.66) 

Eucinostomus 

melanopterus 

Flagfin mojarra Gerreidae I 9% 0.19 (0.16) 0.12 (0.08) 

Eucinostomus sp. Mojarra sp. Gerreidae I 1% 0.07 (0.07) 0.1 (0.1) 

Euthynnus alletteratus Little tuny Scombridae P 1% 0.03 (0.03) 31.28 (31.35) 

Gerres cinereus Yellowfin mojarra Gerreidae I 10% 0.05 (0.02) 0.44 (0.24) 

Gnatholepis thompsoni Goldspot goby Gobiidae H 14% 0.73 (0.18) 0.3 (0.07) 

Gobiidae sp. Goby sp. Gobiidae I 1% 0.02 (0.02) 0.01 (0.01) 

Gramma loreto Fairy basslet Grammatidae I 8% 0.57 (0.19) 0.34 (0.1) 

Haemulon aurolineatum Tomtate Haemulidae I 10% 0.51 (0.27) 18.9 (9.06) 

Haemulon carbonarium Caesar grunt Haemulidae I 2% 0.07 (0.05) 3.75 (2.82) 

Haemulon 

chrysargyreum 

Smallmouth grunt Haemulidae I 1% 0.01 (0.01) 0.18 (0.17) 

Haemulon 

flavolineatum 

French grunt Haemulidae I 29% 0.73 (0.22) 45.4 (12.14) 

Haemulon 

macrostomum 

Spanish grunt Haemulidae I 1% 0.01 (0.01) 0.02 (0.02) 

Haemulon parra Sailors choice Haemulidae I 2% <0.01 (<0.01) 0.07 (0.05) 

Haemulon plumierii White grunt Haemulidae I 15% 0.53 (0.19) 34.05 (8.56) 

Haemulon sciurus Bluestriped grunt Haemulidae I 18% 0.18 (0.06) 23.41 (6.54) 

Haemulon striatum Striped grunt Haemulidae I 1% 0.01 (0.01) 0.25 (0.25) 

Haemulon sp. Grunt sp. Haemulidae I 18% 4.88 (1.54) 2.91 (1.03) 

Halichoeres bivittatus Slippery dick Labridae I 28% 1.99 (0.36) 10.73 (2.07) 

Halichoeres garnoti Yellowhead wrasse Labridae I 40% 2.98 (0.29) 27.15 (3.35) 

Halichoeres 

maculipinna 

Clown wrasse Labridae I 10% 0.2 (0.06) 0.29 (0.08) 

Halichoeres pictus Rainbow wrasse Labridae I 1% 0.01 (0.01) 0.03 (0.03) 

Halichoeres poeyi Blackear wrasse Labridae I 16% 0.39 (0.09) 1.87 (0.55) 

140 
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Appendix A

Table A.2 (continued). Mean species site frequency, density, and biomass for fish species observed within the La Parguera study area 

in the August 2008-2010 surveys. 

species Common name family trophic 

group 

% of 

surveys 

mean 

density (se) 

mean 

biomass (se) 

Halichoeres radiatus Puddingwife Labridae I 5% 0.06 (0.02) 1.02 (0.5) 

Heteroconger longissimus Brown garden eel Congridae PL 4% 1.46 (0.65) 64.93 (29.62) 

Heteropriacanthus 

cruentatus 

Glasseye snapper Priacanthidae PL 1% 0.01 (0.01) 0.21 (0.21) 

Holacanthus tricolor Rock beauty Pomacanthidae I 7% 0.11 (0.03) 7.56 (2.59) 

Holocentrus adscensionis Squirrelfish Holocentridae I 7% 0.1 (0.03) 6.44 (2.52) 

Holocentrus rufus Longspine 

squirrelfish 

Holocentridae I 31% 0.46 (0.05) 34.47 (4.13) 

Hypoplectrus chlorurus Yellowtail hamlet Serranidae I 9% 0.13 (0.04) 1.18 (0.46) 

Hypoplectrus guttavarius Shy hamlet Serranidae I 1% 0.01 (0.01) 0.06 (0.04) 

Hypoplectrus indigo Indigo hamlet Serranidae I 2% 0.02 (0.01) 0.06 (0.04) 

Hypoplectrus nigricans Black hamlet Serranidae I 2% 0.02 (0.01) 0.12 (0.06) 

Hypoplectrus puella Barred hamlet Serranidae I 12% 0.17 (0.04) 0.98 (0.25) 

Hypoplectrus unicolor Butter hamlet Serranidae I 10% 0.12 (0.03) 0.85 (0.28) 

Hypoplectrus sp. Hamlet sp. Serranidae I 6% 0.1 (0.03) 0.22 (0.09) 

Inermia vittata Boga Inermiidae PL 1% 0.01 (0.01) 0.15 (0.15) 

Jenkinsia sp. Herring sp. Clupeidae PL 2% 0.36 (0.27) 0.02 (0.01) 

Lachnolaimus maximus Hogfish Labridae I 4% 0.04 (0.02) 2 (0.86) 

Lactophrys bicaudalis Spotted trunkfish Ostraciidae I 2% 0.02 (0.01) 0.43 (0.31) 

Lactophrys trigonus Trunkfish Ostraciidae I 1% 0.01 (0.01) 1.36 (0.97) 

Lonchopisthus micrognathus Swordtail jawfish Opistognathidae P 3% 0.05 (0.02) 0.31 (0.14) 

Lutjanus analis Mutton snapper Lutjanidae I 1% 0.01 (0.01) 11.68 (11.68) 

Lutjanus apodus Schoolmaster Lutjanidae P 19% 0.25 (0.12) 16.73 (6.61) 

Lutjanus cyanopterus Cubera snapper Lutjanidae P 1% <0.01 (<0.01) 0.11 (0.11) 

Lutjanus griseus Gray snapper Lutjanidae I 10% 0.01 (<0.01) 1.56 (0.53) 

Lutjanus jocu Dog snapper Lutjanidae P 1% 0.01 (0.01) 0.47 (0.45) 

Lutjanus mahogoni 

Lutjanus synagris 

Mahogany snapper 

Lane snapper 

Lutjanidae 

Lutjanidae 

P 

I 

1% 

9% 

0.02 (0.02) 

0.3 (0.11) 

7.54 (7.54) 

4.52 (1.6) 

Malacanthus plumieri Sand tilefish Malacanthidae I 3% 0.04 (0.02) 10.01 (4.41) 

Malacoctenus boehlkei Diamond blenny Labrisomidae I 2% 0.02 (0.01) 0.02 (0.02) 

Malacoctenus macropus Rosy blenny Labrisomidae I 3% 0.04 (0.02) 0.03 (0.01) 

Malacoctenus triangulatus Saddled blenny Labrisomidae I 2% 0.02 (0.01) 0.06 (0.03) 

Malacoctenus sp. Scaly Blenny sp. Labrisomidae I 1% 0.01 (0.01) <0.01 (<0.01) 

Melichthys niger Black durgon Balistidae H 1% 0.04 (0.04) 24.72 (18.85) 

Microgobius carri Seminole goby Gobiidae H 1% 0.01 (0.01) 0.02 (0.02) 

Microgobius signatus Microgobius 

signatus 

Gobiidae H 1% 0.04 (0.03) 0.01 (0.01) 

Microspathodon chrysurus Yellowtail damselfish Pomacentridae H 14% 0.35 (0.11) 20.46 (5.58) 

Monacanthus ciliatus Fringed filefish Monacanthidae H 1% 0.01 (0.01) 0.01 (<0.01) 

Monacanthus tuckeri Slender filefish Monacanthidae PL 1% 0.01 (0.01) 0.01 (0.01) 

Mulloidichthys martinicus Yellow goatfish Mullidae I 3% 0.09 (0.05) 8.69 (5.5) 

Myripristis jacobus Blackbar soldierfish Holocentridae I 3% 0.05 (0.02) 4.28 (1.93) 

Neoniphon marianus Longjaw squirrelfish Holocentridae I 2% 0.03 (0.01) 0.62 (0.41) 

141 
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Appendix A

Table A.2 (continued). Mean species site frequency, density, and biomass for fish species observed within the La Parguera study area 

in the August 2008-2010 surveys. 

species Common name family trophic 

group 

% of 

surveys 

mean 

density (se) 

mean 

biomass (se) 

Nes longus Orangespotted goby Gobiidae H 14% 1.65 (0.42) 6 (1.76) 

Ocyurus chrysurus Yellowtail snapper Lutjanidae PL 38% 1.29 (0.22) 57.45 (13.64) 

Ophioblennius macclurei Redlip blenny Blenniidae H 2% 0.02 (0.01) 0.05 (0.04) 

Opistognathus aurifrons Yellowhead jawfish Opistognathidae PL 9% 0.32 (0.09) 0.56 (0.19) 

Opistognathus 

macrognathus 

Banded jawfish Opistognathidae P 1% 0.01 (0.01) 0.04 (0.04) 

Oxyurichthys stigmalophius Spotfin goby Gobiidae H 1% 0.01 (0.01) <0.01 (<0.01) 

Paradiplogrammus bairdi Lancer dragonet Callionymidae I 2% 0.05 (0.02) 0.06 (0.03) 

Pareques acuminatus Highhat Sciaenidae I 1% 0.01 (0.01) <0.01 (<0.01) 

Pomacanthus arcuatus Gray angelfish Pomacanthidae I 8% 0.09 (0.02) 47.47 (16.21) 

Pomacanthus paru French angelfish Pomacanthidae I 1% 0.02 (0.02) 1.84 (1.81) 

Prognathodes aculeatus Longsnout 

butterflyfish 

Chaetodontidae I 1% 0.01 (0.01) 0.07 (0.07) 

Pseudupeneus maculatus Spotted goatfish Mullidae I 18% 0.27 (0.05) 16.03 (4.04) 

Ptereleotris helenae Hovering goby Microdesmidae PL 2% 0.05 (0.03) 0.27 (0.21) 

Sargocentron vexillarium Dusky squirrelfish Holocentridae I 1% 0.01 (0.01) 0.2 (0.2) 

Scarus guacamaia Rainbow parrotfish Scaridae H 1% <0.01 (<0.01) 0.03 (0.03) 

Scarus iseri Striped parrotfish Scaridae H 49% 6.16 (1.11) 93.15 (16.04) 

Scarus taeniopterus Princess parrotfish Scaridae H 34% 2.79 (0.38) 94 (14.34) 

Scarus vetula Queen parrotfish Scaridae H 2% 0.03 (0.02) 0.58 (0.34) 

Scomberomorus regalis Cero Scombridae P 1% 0.02 (0.02) 19.95 (14.13) 

Scorpaena plumieri Spotted 

scorpionfish 

Scorpaenidae I 1% 0.01 (0.01) 0.59 (0.59) 

Serranus baldwini Lantern bass Serranidae P 5% 0.1 (0.03) 0.1 (0.04) 

Serranus flaviventris Twinspot bass Serranidae P 1% 0.01 (0.01) 0.03 (0.03) 

Serranus tabacarius Tobaccofish Serranidae P 9% 0.15 (0.04) 0.28 (0.08) 

Serranus tigrinus Harlequin bass Serranidae I 15% 0.29 (0.05) 1.43 (0.3) 

Serranus tortugarum Chalk bass Serranidae PL 6% 0.49 (0.21) 0.35 (0.12) 

Sparisoma atomarium Greenblotch 

parrotfish 

Scaridae H 17% 0.55 (0.13) 0.63 (0.2) 

Sparisoma aurofrenatum Redband parrotfish Scaridae H 50% 4.22 (0.29) 117.71 (11.01) 

Sparisoma chrysopterum Redtail parrotfish Scaridae H 1% 0.02 (0.01) 6.44 (4.78) 

Sparisoma radians Bucktooth 

parrotfish 

Scaridae H 19% 1.44 (0.3) 1.49 (0.43) 

Sparisoma rubripinne Yellowtail parrotfish Scaridae H 4% 0.07 (0.04) 10.33 (7.73) 

Sparisoma sp. Parrotfish sp. Scaridae H 2% 0.04 (0.03) 0.05 (0.04) 

Sparisoma viride Stoplight parrotfish Scaridae H 35% 1.5 (0.2) 172.66 (30.64) 

Sphoeroides spengleri Bandtail puffer Tetraodontidae I 3% 0.03 (0.01) 0.15 (0.1) 

Sphoeroides testudineus Checkered puffer Tetraodontidae I 5% 0.02 (0.01) 0.2 (0.09) 

Sphyraena barracuda Great barracuda Sphyraenidae P 12% 0.03 (0.01) 102.34 (90.65) 

Stegastes adustus Dusky damselfish Pomacentridae H 5% 0.84 (0.38) 6.94 (3.49) 

Stegastes diencaeus Longfin damselfish Pomacentridae H 7% 0.37 (0.14) 2.33 (0.98) 

Stegastes leucostictus Beaugregory Pomacentridae I 30% 1 (0.27) 4.87 (1.03) 

Stegastes partitus Bicolor damselfish Pomacentridae H 44% 3.35 (0.35) 6.46 (1.73) 

Stegastes planifrons Threespot damselfish Pomacentridae I 8% 0.5 (0.19) 4.88 (1.76) 

Stegastes variabilis Cocoa damselfish Pomacentridae H 19% 0.6 (0.13) 5.63 (1.22) 

142 
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Appendix A

Table A.2 (continued). Mean species site frequency, density, and biomass for fish species observed within the La Parguera study area 

in the August 2008-2010 surveys. 

species Common name family trophic 

group 

% of 

surveys 

mean 

density (se) 

mean 

biomass (se) 

Syacium sp. Sand Flounder sp. Paralichthyidae I 1% 0.01 (0.01) <0.01 (<0.01) 

Syngathus dawsoni NOT RECORDED Syngnathidae I 1% 0.01 (0.01) 0.01 (0.01) 

Synodus foetens Inshore lizardfish Synodontidae P 1% 0.01 (0.01) <0.01 (<0.01) 

Synodus intermedius Sand diver Synodontidae P 3% 0.03 (0.01) 0.21 (0.12) 

Thalassoma bifasciatum Bluehead Labridae I 43% 6.62 (0.81) 6.8 (1.56) 

Xyrichtys martinicensis Rosy razorfish Labridae I 3% 0.2 (0.1) 0.36 (0.21) 

Xyrichtys novacula Pearly razorFish Labridae I 1% 0.01 (0.01) 0.03 (0.03) 

Xyrichtys splendens Green razorfish Labridae I 1% 0.01 (0.01) 0.02 (0.02) 

143 

Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Appendix B

Appendix b
 

Figure B.1. Concentrations of aldrin (ng/g) in sediments. 

145 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Appendix B

146 

Figure B.2. Concentrations of dieldrin (ng/g) in sediments. 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Appendix B

Figure B.3. Concentrations of endrin (ng/g) in sediments. 

147 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Appendix B

148 

Figure B.4. Concentrations of tetrachlorobenzen (ng/g) in sediments. 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Appendix B

Figure B.5. Concentrations of pentachlorobenzene (ng/g) in sediments. 

149 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Appendix B

150 

Figure B.6. Concentrations of hexachlorobenzene (ng/g) in sediments. 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Appendix B

Figure B.7. Concentrations of pentachloroanisole (ng/g) in sediments. 

151 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Appendix B

152 

Figure B.8. Concentrations of endosulfan II (ng/g) in sediments. 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Appendix B

Figure B.9. Concentrations of endosulfan sulfate (ng/g) in sediments. 

153 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Appendix B

154 

Figure B.10. Concentrations of chlorpyrifos (ng/g) in sediments. 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Appendix B

Figure B.11. Concentrations of mirex (ng/g) in sediments. 

155 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Appendix B

156 

Figure B.12. Supplemental watershed sampling sites. 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Appendix B

Figure B.13. Concentrations of total chlordane (ng/g) in watershed sediments. 

157 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Appendix B

158 

Figure B.14. Concentrations of total PCBs (ng/g) in watershed sediments. 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Appendix B

Figure B.15. Concentrations of total DDTs (ng/g) in watershed sediments. 

159 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Appendix B

160 

Figure B.16. Concentrations of nickel (μg/g) in watershed sediments. 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Appendix B

Figure B.17. Concentrations of chromium (μg/g) in watershed sediments. 

161 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Appendix B

162 

Figure B.18. Concentrations of zinc (μg/g) in watershed sediments. 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Appendix C 

0.006 

0.008 

0.01 

0.002 

0.003 

0.004 

0.005 

0.014 

mg-P/L mg-N/L mg-N/L 

0.01 

07/01/2009 07/01/2009 07/01/2009

08/26/2009 08/26/2009 08/26/2009

10/21/2009 10/21/2009 10/21/2009

12/16/2009 12/16/2009 12/16/2009

Appendix C 

NH4+ rain (mm) NO3-+NO2- rain (mm) 0.02 120 

0.016 120 0.018 

0.014 100 0.016 100 

0.012 0.014 80 80 

40 40 0.006 

0.004 0.004 20 20 0.002 0.002 

0 0 0 0

Figure C.1. Time series of precipitation (Lajas) and oxidized Figure C.2. Time series of precipitation (Lajas) and ammonium nitrogen (nitrate plus nitrite) concentrations from N13 (Offshore concentrations from N13 (Offshore East strata). East strata).
	

Urea rain (mm) Total N rain (mm) 0.007 120 0.45 120 

0.4 0.006 100 100 

0.35 

40 

60 

0.2 

0.15 40

0.1 

0.001 20 

0.05 

20 

0 0 0 0 

Figure C.3. Time series of precipitation (Lajas) and urea Figure C.4. Time series of precipitation (Lajas) and total nitrogen 

concentrations from N13 (Offshore East strata). concentrations from N13 (Offshore East strata). 

HPO4= Total P rain (mm) rain (mm) 0.018 120 0.08 120 

0.016 0.07 100 100 

60 

0.008 

0.03 

0.006 40 40

0.02 0.004 

20 20 0.01 0.002 

0 0 0 0

Figure C.5. Time series of precipitation (Lajas) and orthophosphate Figure C.6. Time series of precipitation (Lajas) and total phosphorus 

concentrations from N13 (Offshore East strata). concentrations from N13 (Offshore East strata). mm 02/10/2010 04/10/2010 06/06/2010 08/01/2010 09/26/2010 11/21/2010 01/16/2011 03/13/2011 05/08/2011 07/03/2011 08/28/2011 10/23/2011 12/19/2011 02/15/2012 04/11/2012 06/07/2012 08/05/2012 

0.012 80 02/10/2010 04/10/2010 06/06/2010 08/01/2010 09/26/2010 11/21/2010 01/16/2011 03/13/2011 05/08/2011 07/03/2011 08/28/2011 10/23/2011 12/19/2011 02/15/2012 04/11/2012 06/07/2012 08/05/2012 

60 

80 

02/10/201004/10/201006/06/201008/01/201009/26/201011/21/201001/16/201103/13/201105/08/201107/03/201108/28/201110/23/201112/19/201102/15/201204/11/201206/07/201208/05/2012 

60 

mm 

mm 

mg-P/L mg-N/L mg-P/l 

07/01/200908/22/200910/13/200912/04/200901/25/201003/20/201005/13/201007/04/201008/25/201010/16/201012/07/201001/28/201103/21/201105/12/201107/03/201108/24/201110/15/201112/06/201101/28/2012

0.25 

0.3 80 07/01/2009 08/24/2009 10/17/2009 12/10/2009 02/02/2010 03/30/2010 05/25/2010 07/18/2010 09/10/2010 11/03/2010 12/27/2010 02/19/2011 04/14/2011 06/07/2011 07/31/2011 09/23/2011 11/16/2011 01/10/2012

0.008 

0.01 60 

0.012 

07/01/200908/26/200910/21/200912/16/200902/10/201004/10/201006/06/201008/01/201009/26/201011/21/201001/16/201103/13/201105/08/201107/03/201108/28/201110/23/201112/19/201102/15/2012

0.04 60 

0.05 

0.06 

80 

04/11/2012 03/22/2012 03/06/201206/07/201208/05/2012 

05/13/2012 04/29/201207/07/2012 06/24/201208/30/2012 08/20/2012 

mm 

mm mm 

163 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Appendix C

60 

0.01 

0.006 

0.004 

0.002 

mg-P/L mg-N/L mg-N/L 

0.1 

0.15 

07/01/2009 07/01/2009

07/01/200908/26/2009

08/26/2009 08/26/2009 10/21/200910/21/2009 10/21/2009 12/16/2009

0.02 

0 0 0 

Figure C.11. Time series of precipitation (Lajas) and orthophosphate Figure C.12. Time series of precipitation (Lajas) and total 

concentrations from N17 (Offshore West strata). phosphorus concentrations from N17 (Offshore West strata). 

20 

0.06 

0.04 

0.08 

40 

0.25 

NO3-+NO2­ rain (mm) 

120 0.025 

NH4+ rain (mm) 120 

0.2 100 0.02 100 

80 80 

Figure C.7. Time series of precipitation (Lajas) and oxidized Figure C.8. Time series of precipitation (Lajas) and ammonium

nitrogen (nitrate plus nitrite) concentrations from N17 (Offshore concentrations from N17 (Offshore West strata).
	

West strata).
	

Urea rain (mm) Total N rain (mm) 

0.6 120 0.025 120 

0.5 100 100 0.02 

60 

0.01 0.2 40 

0.005 0.1 20 20 

0 0 0 0 

Figure C.9. Time series of precipitation (Lajas) 

concentrations from N17 (Offshore West strata). 

and urea Figure C.10. Time series of precipitation (Lajas) and total nitrogen 

concentrations from N17 (Offshore West strata). 

0.012 

0.014 

HPO4= rain (mm) 

100 

120 

0.16 

0.18 

0.2 

Total P rain (mm) 

100 

120 

0.14 

mm 

40 40 

0.05 20 0.005 20 

0 0 0 0 12/16/2009 02/10/2010 04/10/2010 06/06/2010 08/01/2010 09/26/2010 11/21/2010 01/16/2011 03/13/2011 05/08/2011 07/03/2011 08/28/2011 10/23/2011 12/19/2011 02/15/2012 04/11/2012 06/07/2012 08/05/2012 

0.008 

60 

80 

12/16/200902/10/201004/10/201006/06/201008/01/201009/26/201011/21/201001/16/201103/13/201105/08/201107/03/201108/28/201110/23/201112/19/201102/15/201204/11/201206/07/201208/05/2012 

80 

0.015 

02/10/201004/10/201006/06/201008/01/201009/26/201011/21/201001/16/201103/13/201105/08/201107/03/201108/28/201110/23/201112/19/201102/15/201204/11/201206/07/201208/05/2012 

mm

mg-P/L mg-N/L 

07/01/200908/26/200910/21/200912/16/200902/10/201004/10/201006/06/201008/01/201009/26/201011/21/201001/16/201103/13/201105/08/201107/03/201108/28/201110/23/201112/19/2011

0.1 

0.12 

07/01/200908/26/200910/21/200912/16/200902/10/201004/10/201006/06/201008/01/201009/26/201011/21/201001/16/201103/13/201105/08/201107/03/201108/28/201110/23/201112/19/2011

0.3 

0.4 

07/01/200908/26/200910/21/200912/16/200902/10/201004/10/201006/06/201008/01/201009/26/201011/21/201001/16/201103/13/201105/08/201107/03/201108/28/201110/23/201112/19/2011

60 

mm

mg-N/L 

0.01 

0.015 

02/15/201204/11/2012

02/15/2012 02/15/2012

06/07/201208/05/2012 

04/11/2012 04/11/201206/07/2012 06/07/201208/05/2012 08/05/2012 

mm mm mm 

164 

0 

20 

40 

60 

80 

40 

60 

80 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Appendix C 

0.2 

0.25 

0.3 80 

mm

80 

0.015 

0.45 

NO3-+NO2­ rain (mm) 

120 0.025 

NH4+ rain (mm) 

120 

0.4 

0.35 

100 

0.02 100 

0.15 40 

0.01 

40 

0.05 

0.1 

20 0.005 20 

0 0 0 0 

Figure C.13. Time series of precipitation (Lajas) and oxidized Figure C.14. Time series of precipitation (Lajas) and ammonium

nitrogen (nitrate plus nitrite) concentrations from N28 (Offshore concentrations from N28 (Offshore Central strata).

Central strata).
	

Urea rain (mm) Total N rain (mm) 

0.5 120 0.016 120 

0.45 

0.014 100 100 0.4 

0.012 

0.008 60 

0.002 

0.004 

0.006 

20 

40 

0.05 

0.1 

0.15 

0.2 

20 

40 

0 0 0 0 

Figure C.15. Time series of precipitation (Lajas) and urea Figure C.16. Time series of precipitation (Lajas) and total nitrogen 

concentrations from N28 (Offshore Central strata). concentrations from N28 (Offshore Central strata). 

HPO4= Total P rain (mm) rain (mm) 0.03 120 0.08 120 

0.07 

0.025 100 100 

0.06 

0.01 40 

0.03 40 

0.02 

0.005 20 20 0.01 

0 0 0 0

mg-P/L 

mg-N/L mg-N/L 

0.015 60 

0.02 80 07/01/2009 08/26/2009 10/21/2009 12/16/2009 02/10/2010 04/10/2010 06/06/2010 08/01/2010 09/26/2010 11/21/2010 01/16/2011 03/13/2011 05/08/2011 07/03/2011 08/28/2011 10/23/2011 12/19/2011 02/15/2012 04/11/2012 06/07/2012 08/05/2012 

80 0.01 07/01/2009 08/26/2009 10/21/2009 12/16/2009 02/10/2010 04/10/2010 06/06/2010 08/01/2010 09/26/2010 11/21/2010 01/16/2011 03/13/2011 05/08/2011 07/03/2011 08/28/2011 10/23/2011 12/19/2011 02/15/2012 04/11/2012 06/07/2012 08/05/2012 

60 

mm 

mm 

mg-P/L mg-N/L mg-N/L 

0.3 

0.25 60 

0.35 80 07/01/2009 08/26/2009 10/21/2009 12/16/2009 02/10/2010 04/10/2010 06/06/2010 08/01/2010 09/26/2010 11/21/2010 01/16/2011 03/13/2011 05/08/2011 07/03/2011 08/28/2011 10/23/2011 12/19/2011 02/15/2012 04/11/2012 06/07/2012 08/05/2012 

60 

0.04 60 

0.05 

07/01/200908/26/200910/21/200912/16/200902/10/201004/10/201006/06/201008/01/201009/26/201011/21/201001/16/201103/13/201105/08/201107/03/201108/28/201110/23/201112/19/201102/15/201204/11/201206/07/2012

80 08/05/2012 

mm 

mm mm 

Figure C.17. Time series of precipitation (Lajas) and orthophosphate Figure C.18. Time series of precipitation (Lajas) and total 

concentrations from N28 (Offshore Central strata). phosphorus concentrations from N28 (Offshore Central strata). 07/01/2009 08/26/2009 10/21/2009 12/16/2009 02/10/2010 04/10/2010 06/06/2010 08/01/2010 09/26/2010 11/21/2010 01/16/2011 03/13/2011 05/08/2011 07/03/2011 08/28/2011 10/23/2011 12/19/2011 02/15/2012 04/11/2012 06/07/2012 08/05/2012 07/01/2009 08/29/2009 10/27/2009 12/25/2009 02/23/2010 04/25/2010 06/24/2010 08/22/2010 10/20/2010 12/18/2010 02/15/2011 04/15/2011 06/13/2011 08/11/2011 10/09/2011 12/07/2011 02/05/2012 04/06/2012 06/05/2012 08/06/2012 

165 
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Appendix C

60 

80 0.5 80 

0.1 

0.12 

0.8 

NO3-+NO2­ rain (mm) 

120 0.18 

NH4+ rain (mm) 120 

0.6 

0.7 100 

0.14 

0.16 

100 

mg-N/L mg-N/L 

mg-P/L 

0.015 60 

0.02 80 07/01/2009 08/26/2009 10/21/2009 12/16/2009 02/11/2010 04/10/2010 06/06/2010 08/01/2010 09/26/2010 11/21/2010 01/16/2011 03/13/2011 05/08/2011 07/03/2011 08/28/2011 10/23/2011 12/19/2011 02/15/2012 04/11/2012 06/07/2012 08/05/2012 

0.4 60 

0.25 07/01/2009

08/26/200910/21/200912/16/200902/11/201004/10/201006/06/201008/01/201009/26/201011/21/201001/16/201103/13/201105/08/201107/03/201108/28/201110/23/201112/19/201102/15/201204/11/201206/07/201208/05/2012 

80 

mm 

mm mm 

mg-N/L mg-N/L mg-P/L 

0.3 

0.35 

80 

0.8 

60 

0.6 07/01/2009

08/26/200910/21/200912/16/200902/11/201004/10/201006/06/201008/01/201009/26/201011/21/201001/16/201103/13/201105/08/201107/03/201108/28/201110/23/201112/19/201102/15/201204/11/201206/07/201208/05/2012 

0.08 

07/01/200908/26/200910/21/200912/16/200902/11/201004/10/201006/06/201008/01/201009/26/201011/21/201001/16/201103/13/201105/08/201107/03/201108/28/201110/23/201112/19/201102/15/201204/11/201206/07/201208/05/2012 

80 

mm 

mm 

mm 

Figure C.23. Time series of precipitation (Lajas) and Figure C.24. Time series of precipitation (Lajas) and total 

orthophosphate concentrations from N18 (North Bay strata). phosphorus concentrations from N18 (North Bay strata). 07/01/2009 08/26/2009 10/21/2009 12/16/2009 02/11/2010 04/10/2010 06/06/2010 08/01/2010 09/26/2010 11/21/2010 01/16/2011 03/13/2011 05/08/2011 07/03/2011 08/28/2011 10/23/2011 12/19/2011 02/15/2012 04/11/2012 06/07/2012 08/05/2012 07/01/2009 08/26/2009 10/21/2009 12/16/2009 02/11/2010 04/10/2010 06/06/2010 08/01/2010 09/26/2010 11/21/2010 01/16/2011 03/13/2011 05/08/2011 07/03/2011 08/28/2011 10/23/2011 12/19/2011 02/15/2012 04/11/2012 06/07/2012 08/05/2012 

0.1 20 20 0.05 0.05 

0 0 0 0 

0.1 

0.2 60 

0.15 40 

0.25 60 

0.2 

0.15 40 

0.3 40 0.06 40 

0.1 

0.2 

20 

0.02 

0.04 

20 

0 0 0 0 

Figure C.19. Time series of precipitation (Lajas) and oxidized Figure C.20. Time series of precipitation (Lajas) and ammonium

nitrogen (nitrate plus nitrite) concentrations from N18 (North Bay concentrations from N18 (North Bay strata).

strata).
	

Urea rain (mm) Total N rain (mm) 

0.03 120 1.4 120 

1.2 0.025 100 100 

1 

0.01 40 40 

0.4 

0.005 20 0.2 20 

0 0 0 0 

Figure C.21. Time series of precipitation (Lajas) and urea Figure C.22. Time series of precipitation (Lajas) and total nitrogen 

concentrations from N18 (North Bay strata). concentrations from N18 (North Bay strata). 

HPO4= rain (mm) Total P rain (mm) 0.4 120 0.5 120 

0.45 

100 0.35 

100 0.4 0.3 

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Appendix C 

1 

1.5 

2 

2.5 

0.01 

0.02 

mg-N/L 

80 

0.12 

0.14 80 

NO3-+NO2- rain (mm) NH4+ rain (mm) 4 120 0.2 120 

3.5 0.18 

100 100 0.16 3 

mg-P/L mg-N/L 

60 

80 

mm 

07/01/200908/26/200910/21/200912/16/200902/11/201004/10/201006/06/201008/01/201009/26/201011/21/201001/16/201103/13/201105/08/201107/03/201108/28/201110/23/201112/19/201102/15/201204/11/201206/07/201208/05/2012 

0.015 60 

80 

07/01/200908/26/200910/21/200912/16/200902/11/201004/10/201006/06/201008/01/201009/26/201011/21/201001/16/201103/13/201105/08/201107/03/201108/28/201110/23/201112/19/201102/15/201204/11/201206/07/201208/05/2012 

60 

mm mm 

mg-P/L mg-N/L mg-N/L 

0.5 07/01/2009

08/22/200910/13/200912/04/200901/25/201003/20/201005/13/201007/04/201008/25/201010/16/201012/07/201001/28/201103/21/201105/12/201107/03/201108/24/201110/15/201112/06/201101/28/201203/22/201205/13/201207/07/201208/30/2012 

mm 

3 80 

2.5 

60 

07/01/200908/26/200910/21/200912/16/200902/11/201004/10/201006/06/201008/01/201009/26/201011/21/201001/16/201103/13/201105/08/201107/03/201108/28/201110/23/201112/19/201102/15/201204/11/201206/07/201208/05/2012 

mm mm 

Figure C.29. Time series of precipitation (Lajas) and Figure C.30. Time series of precipitation (Lajas) and total 

orthophosphate concentrations from N23 (Central Bay strata). phosphorus concentrations from N23 (Central Bay strata). 07/01/2009 08/26/2009 10/21/2009 12/16/2009 02/11/2010 04/10/2010 06/06/2010 08/01/2010 09/26/2010 11/21/2010 01/16/2011 03/13/2011 05/08/2011 07/03/2011 08/28/2011 10/23/2011 12/19/2011 02/15/2012 04/11/2012 06/07/2012 08/05/2012 07/01/2009 08/26/2009 10/21/2009 12/16/2009 02/11/2010 04/10/2010 06/06/2010 08/01/2010 09/26/2010 11/21/2010 01/16/2011 03/13/2011 05/08/2011 07/03/2011 08/28/2011 10/23/2011 12/19/2011 02/15/2012 04/11/2012 06/07/2012 08/05/2012 

0.2 

0.1 20 

0.1 20 

0 0 0 0 

40 40 

0.4 60 

0.3 

40 

0.1 60 

0.08 

0.06 40 

0.04 20 20 0.5 0.02 

0 0 0 0 

Figure C.25. Time series of precipitation (Lajas) and oxidized Figure C.26. Time series of precipitation (Lajas) and ammonium

nitrogen (nitrate plus nitrite) concentrations from N23 (Central Bay concentrations from N23 (Central Bay strata).

strata).
	

Urea rain (mm) Total N rain (mm) 0.03 120 4.5 120 

4 

0.025 100 100 

3.5 

40 

2 

1.5 40 

0.005 20 

0.5 

1 

20 

0 0 0 0 

Figure C.27. Time series of precipitation (Lajas) 

concentrations from N23 (Central Bay strata). 

and urea Figure C.28. Time series of precipitation (Lajas) and total nitrogen 

concentrations from N23 (Central Bay strata). 

0.6 

HPO4= rain (mm) 

120 0.8 

Total P rain (mm) 120 

0.5 100 

0.7 100 

0.6 

80 

167 

0.2 

0.3 

0.4 
Baseline Assessment of Guánica Bay, Puerto Rico in Support of Watershed Restoration

Appendix C

60 

80 

mg-N/L 

0.2 

80 

mm

0.1 

NO3-+NO2- rain (mm) NH4+ rain (mm) 0.35 120 0.16 120 

0.14 0.3 100 100 

0.12 0.25 

60 

0.15 

0.1 

40 

0.04 

0.06 40 

0.05 20 0.02 20 

0 0 0 0 

Figure C.31. Time series of precipitation (Lajas) and oxidized Figure C.32. Time series of precipitation (Lajas) and ammonium

nitrogen (nitrate plus nitrite) concentrations from N24 (South Bay concentrations from N24 (South Bay strata).

strata).
	

Urea rain (mm) 120 Total N rain (mm) 0.03 1 120 

0.9 

0.025 100 100 0.8 

0.015 60 0.5 

0.4 

0.01 40 0.3 40 

0.005 20 0.2 20 

0.1 

0 0 0 0 

Figure C.33. Time series of precipitation (Lajas) and urea Figure C.34. Time series of precipitation (Lajas) and total nitrogen 

concentrations from N24 (South Bay strata). concentrations from N24 (South Bay strata). 

HPO4= rain (mm) Total P rain (mm) 0.3 120 0.4 120 

0.35 0.25 100 100 

0.3 

0.1 40 

0.2 60 

0.15 40 

0.1 

0.05 20 20 0.05 

0 0 0 0

mg-N/L 

mg-P/L 

0.15 60 

0.2 80 

mm 

07/01/200908/26/200910/21/200912/16/200902/11/201004/10/201006/06/201008/01/201009/26/201011/21/201001/16/201103/13/201105/08/201107/03/201108/28/201110/23/201112/19/201102/15/201204/11/201206/07/201208/05/2012 

0.02 80 07/01/2009 08/26/2009 10/21/2009 12/16/2009 02/11/2010 04/10/2010 06/06/2010 08/01/2010 09/26/2010 11/21/2010 01/16/2011 03/13/2011 05/08/2011 07/03/2011 08/28/2011 10/23/2011 12/19/2011 02/15/2012 04/11/2012 06/07/2012 08/05/2012 

mm 

mg-P/L mg-N/L mg-N/L 

0.6 

0.7 

80 0.25 07/01/2009 08/26/2009 10/21/2009 12/16/2009 02/11/2010 04/10/2010 06/06/2010 08/01/2010 09/26/2010 11/21/2010 01/16/2011 03/13/2011 05/08/2011 07/03/2011 08/28/2011 10/23/2011

0.08 

07/01/200908/26/200910/21/200912/16/200902/11/201004/10/201006/06/201008/01/201009/26/201011/21/201001/16/201103/13/201105/08/201107/03/201108/28/2011

12/19/2011 10/23/2011

12/19/2011 02/15/2012

04/11/2012 02/15/201206/07/201208/05/2012 

04/11/201206/07/201208/05/2012 

mm 

mm 

mm 

Figure C.35. Time series of precipitation (Lajas) and Figure C.36. Time series of precipitation (Lajas) and total 

orthophosphate concentrations from N24 (South Bay strata). phosphorus concentrations from N24 (South Bay strata). 07/01/2009 08/26/2009 10/21/2009 12/16/2009 02/11/2010 04/10/2010 06/06/2010 08/01/2010 09/26/2010 11/21/2010 01/16/2011 03/13/2011 05/08/2011 07/03/2011 08/28/2011 10/23/2011 12/19/2011 02/15/2012 04/11/2012 06/07/2012 08/05/2012 07/01/2009 08/26/2009 10/21/2009 12/16/2009 02/11/2010 04/10/2010 06/06/2010 08/01/2010 09/26/2010 11/21/2010 01/16/2011 03/13/2011 05/08/2011 07/03/2011 08/28/2011 10/23/2011 12/19/2011 02/15/2012 04/11/2012 06/07/2012 08/05/2012 

168 

60 

80 
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Appendix C 

0.6 

0.8 

1 

0.03 

0.04 

80 0.2 80 

NO3-+NO2- NH4+ rain (mm) rain (mm) 0.3 120 1.4 120 

1.2 0.25 100 100 

60 

40 0.1 40

0.4 

20 0.05 20 0.2 

0 0 0 0

Figure C.37. Time series of precipitation (Lajas) and oxidized Figure C.38. Time series of precipitation (Lajas) and ammonium

nitrogen (nitrate plus nitrite) concentrations from N33 (Watershed concentrations from N33 (Watershed Ag Canal strata).
	

Ag Canal strata).
	

Urea rain (mm) Total N rain (mm) 0.06 120 2 120 

1.8 

0.05 100 100 1.6 

1 60 

0.8 

0.02 40 0.6 40 

0.01 20 0.4 20 

0.2 

0 0 0 0 

Figure C.39. Time series of precipitation (Lajas) and urea Figure C.40. Time series of precipitation (Lajas) and total nitrogen 

concentrations from N33 (Watershed Ag Canal strata). concentrations from N33 (Watershed Ag Canal strata). 

HPO4= rain (mm) Total P rain (mm) 1.4 120 1.8 120 

1.6 1.2 100 100 

1.4 

0.8 

0.4 

40 0.6 40 

0.4 

0.2 20 

0.2 

20 

0 0 0 0 

mg-P/L mg-N/L mg-N/L 

80 

07/01/200908/26/200910/21/200912/16/200902/11/201004/10/201006/06/201008/01/201009/26/201011/21/201001/16/201103/13/201105/08/201107/03/201108/28/201110/23/201112/19/201102/15/201204/11/201206/07/201208/04/2012 

60 

80 

07/01/200908/26/200910/21/200912/16/200902/11/201004/10/201006/06/201008/01/201009/26/201011/21/201001/16/201103/13/201105/08/201107/03/201108/28/201110/23/201112/19/201102/15/201204/11/201206/07/201208/04/2012 

60 

mm 

mm mm 

mg-P/L mg-N/L mg-N/L 

1.2 

1.4 

0.15 60

1 

60 

1.2 80 07/01/2009 08/26/2009 10/21/2009 12/16/2009 02/11/2010 04/10/2010 06/06/2010 08/01/2010 09/26/2010 11/21/2010 01/16/2011 03/13/2011 05/08/2011 07/03/2011 08/28/2011 10/23/2011 12/19/2011 07/01/2009 08/26/2009 10/21/2009 12/16/2009 02/11/2010 04/10/2010 06/06/2010 08/01/2010 09/26/2010 11/21/2010 01/16/2011 03/13/2011 05/08/2011 07/03/2011 08/28/2011 10/23/2011 02/15/2012 12/19/2011 04/11/2012 02/15/2012 04/11/2012 06/07/2012 08/04/2012 06/07/2012 08/04/2012 

80 

mm 

mm 

mm 

Figure C.41. Time series of precipitation (Lajas) and Figure C.42. Time series of precipitation (Lajas) and total 

orthophosphate concentrations from N33 (Watershed Ag Canal phosphorus concentrations from N33 (Watershed Ag Canal strata). 

strata). 

07/01/200908/26/200910/21/200912/16/200902/11/201004/10/201006/06/201008/01/201009/26/201011/21/201001/16/201103/13/201105/08/201107/03/201108/28/201110/23/201112/19/201102/15/201204/11/201206/07/201208/04/2012 

07/01/200908/26/200910/21/200912/16/200902/11/201004/10/201006/06/201008/01/201009/26/201011/21/201001/16/201103/13/201105/08/201107/03/201108/28/201110/23/201112/19/201102/15/201204/11/201206/07/201208/04/2012 

169 

0.6 

0.8 

1