Florida Fish and Wildlife

Conservation Commission 

National Park Service

U.S. Department of the Interior

South Florida Natural Resources Center

Everglades and Dry Tortugas National Park 

A Science Plan Prepared by the 

National Park Service 

and the 

Florida Fish and Wildlife Conservation Commission

2007

Assessing the Conservation Efficacy of the 

Dry Tortugas National Park

Research Natural Area
RESEARCH NATURAL AREA BOUNDARY

RESEARCH NATURAL AREA BOUNDARY 

Hospital Key

Loggerhead Key

East Key

PARK BOUNDARY

PARK BOUNDARY

D R Y T O R T U G A S

N A T I O N A L P A R K

T O R T U G A S E C O L O G I C A L R E S E R V E

T O R T U G A S N O R T H

F L O R I D A K E Y S

N A T I O N A L M A R I N E

S A N C T U A R Y

D R Y T O R T U G A S N A T I O N A L P A R K

R E A S E A R C H N A T U R A L A R E A

Garden Key

Long Key

0 1 Kilometer

0 1 Statute Mile

0 1 Nautical Mile

North

RESEARCH NATURAL AREA BOUNDARY

Middle Key
Assessing the Conservation Efficacy of the

Dry Tortugas National Park

Research Natural Area

A Science Plan Prepared by the

National Park Service

and the

Florida Fish and Wildlife Conservation Commission

2007

South Florida Natural Resources Center

Everglades and Dry Tortugas National Parks

Homestead, Florida

National Park Service

U.S. Department of the Interior

Florida Fish and Wildlife Conservation Commission

Tallahassee, Florida

Cover photograph of red grouper by Jerry Ault, Univ. of Miami/RSMAS

Cover photograph of blue striped grunt and gray snapper by Brett Seymour, NPS
Assessing the Conservation Efficacy of the Dry Tortugas National Park Research Natural Area iii

EXECUTIVE SUMMARY

Introduction

The newly established Research Natural Area (RNA) of Dry 

Tortugas National Park (DTNP) is a 46-square mile marine 

reserve designed to restore ecological integrity and capacity 

for self-renewal by minimizing the effects of human activities. 

Anchoring and fishing are prohibited within the RNA. This 

report presents a science plan developed by the National Park 

Service (NPS) and the Florida Fish and Wildlife Conservation 

Commission (FWC) that will be used to assess the effectiveness of the RNA.

The goal of establishing the Dry Tortugas National Park 

RNA is to protect shallow water marine habitat, ensure species diversity, and enhance the productivity and sustainability 

of fish populations throughout the region. The RNA provides 

a unique unexploited area that can be used to help assess the 

effects of fishing on exploited areas. Long-term studies and 

monitoring will serve to document existing baseline conditions and analyze how park natural resources respond to the 

protection provided. 

In February 2007, the NPS and the FWC established a 

Memorandum of Understanding (MOU) to facilitate cooperation in the evaluation of six areas of RNA performance. 

A summary description of these six performance areas, together with associated performance measures and monitoring and research activities, is provided here in the Executive 

Summary. An in depth discussion follows in the Monitoring 

and Research Activities section of the main report. While the 

performance areas are described as separate topics, there are 

important interdependencies among them. These relationships are illustrated in Figure 1.

RNA Performance Topic 1: Quantify 

changes in the abundance and sizestructure of exploited species within the 

RNA relative to adjacent areas.

Research suggests that the abundance and population sizestructure of exploited species in the RNA are below levels 

required to sustain the species. An intended conservation 

function of the RNA is to increase the abundance and sizestructure of these exploited species. Multiple scientific studies of no-take marine reserves suggest that these areas have 

served to enhance fisheries.

Performance Measures

Abundances, sizes, occurrence frequency, and estimates 

of fisheries stock assessment parameters for groupers, snappers, and grunts inside and outside the RNA. 

Abundance of reference (non-fishery) reef fishes (e.g., 

parrotfishes).

Essential Activities 

1) Implement an annual coral reef fish visual census (RVC) 

in DTNP using a stratified random sampling design (SRS) 

inside and outside the RNA. 

2) Employ fish traps and hook-and-line gears to collect 

additional information on selected species to evaluate 

changes in relative abundance and size-structure. At least 

initially, data should be collected three times a year. These 

efforts will also provide individual fish for use in tagging 

activities (see Topics 2 and 5).

Supplemental Activities

1) Conduct visual surveys of fishes in seagrass communities inside and outside the RNA. Reef fish species, especially juveniles, found in seagrass beds may be an early 

indicator of RNA success.

2) Conduct seasonal coral reef visual surveys inside and 

outside the RNA to provide additional information on the 

abundance and size of reef fish.

Assessing the Conservation Efficacy of the Dry Tortugas National Park 

Research Natural Area 

Yellowtail snapper and staghorn coral. Photo by William Perry, 

NPS.
iv

RNA Performance Topic 2: Monitor the 

immigration and emigration of targeted 

species in the RNA.

The abundance and size-structure of target species are expected to increase in areas adjacent to no-take marine reserves due to emigration from the protected areas. Recent 

scientific studies of coral reef fisheries confirm that marine reserves have the ability to enhance adjacent fisheries, resulting 

in greater fish biomass (more and larger fish). This outcome is 

commonly known as a spillover effect.

Performance Measures

Net emigration of select species from the snapper-grouper complex from the RNA to adjacent fished areas inside 

and outside DTNP.

Essential Activities 

1) Implement a sonic tagging study to monitor broad 

scale net emigration patterns of selected species from 

the RNA to fished areas in the DTNP region. The study 

area will encompass the Florida Shelf of the DTNP region 

and consist of open fished areas (Natural/Cultural Zone 

(NCZ), DTNP and Florida Keys National Marine Sanctuary 

(FKNMS) waters south of the DTNP to Rebecca Shoals 

(15 km east of DTNP), and regulated marine protected 

areas (RNA, Tortugas South Ecological Reserve (TSER) and 

Tortugas North Ecological Reserve (TNER)). 

2) Use external tags on selected species to monitor broad 

scale net emigration patterns from the RNA to fished 

areas in the DTNP region. Recaptured individuals should 

then be identified from subsequent sampling events as 

well as from reports made by recreational anglers to 

the FWC Fish and Wildlife Research Institute tag return 

hotline. 

Figure 1. There are numerous ecological connections between and among the six distinct topical areas of study identified within the 

DTNP RNA science plan. Information (sampling data, biological specimens, etc.) will be shared across the topical areas as well in order 

to assess efficiently the effects of the no-fishing and no-anchoring management actions on marine resources. 

Assess RNA Conservation Efficacy and Socioeconomic Effects

Assess Effects of No-fishing Assess Effects of No Anchoring

Effects on Fishery

Species Adjacent

to RNA

(Spillover Effects)

Effects on

Fishery

Species in RNA

Larval Production

and Transport

Effects

(Includes Spillover Effects)

Socioeconomic

Effects

Effects on

Tortugas

Fishing Activity

Benthic

Community

Effects

Topic 1 Topic 2 Topic 5 Topic 3 Topic 6 Topic 4

Ecological and/or

Socioeconomic Linkages

Information Flow

RNA Stewardship Actions

Ecological and Socioeconomic Effects of RNA Implementation

Science Plan Activities (RNA PerformanceTopics)

Key to Colored text

Quantifying changes in the abundance and size-structure of exploited species within the RNA relative to adjacent areas.

Monitoring the immigration and emigration of targeted species in the RNA.

Monitoring changes in species composition and catch rates of exploited species throughout the surrounding region.

Evaluate the effects of RNA implementation on marine benthic biological communities.

Assessing reproductive potential of exploited species by evaluating egg production and larval dispersal.

•

•

•

•

•

• Incorporate social sciences into the research and monitoring program.
Assessing the Conservation Efficacy of the Dry Tortugas National Park Research Natural Area 

Supplemental Activities

1) Expand sonic tagging to examine immigration and 

emigration from the RNA to the TSER. 

2) Expand sonic tagging to examine immigration and 

emigration from the RNA to the TNER. 

RNA Performance Topic 3: Monitor 

changes in species composition and catch 

rates of exploited species throughout the 

surrounding region.

The benefits of establishing the RNA may include an enhancement of recreational and commercial fisheries. Recent 

scientific studies of coral reef fisheries have shown that other 

marine reserves have contributed to the enhancement of adjacent fisheries. These effects include more and larger fish, increased catch rates, and reduced fishing effort per catch.

Performance Measures

Catch per unit effort (CPUE), including released fish, harvest per unit effort, estimated total catch and harvest, 

and population size-structure of targeted reef fishery species, especially grouper and snapper species, throughout 

the Tortugas region.

Essential Activities

1) Design and implement an angler creel survey in fished 

areas within DTNP (survey conducted by fixed intercept at 

Garden Key, roving patrol, and via the visitor use permit 

system). This survey should record catch per unit effort 

and sizes of reef fish caught.

2) Collect DTNP permitted charter boat recreational fishing data via a logbook system.

3) Review and utilize data from existing Tortugas recreational and commercial fisheries dependent monitoring 

programs to evaluate the effects of RNA implementation 

on fisheries outside DTNP.

Supplemental Activities

1) Estimate overall fishing activity in DTNP using the park 

visitor use permit system and/or aerial surveys. 

2) Conduct aerial surveys of fishing activities in the 

Tortugas region.

RNA Performance Topic 4: Evaluate the 

effects of RNA implementation on marine 

benthic biological communities.

RNA implementation may have a variety of direct and indirect 

effects on coral reef benthic, and perhaps even seagrass, communities. Prohibiting anchoring in the RNA should greatly reduce or eliminate any anchor damage to coral reef, other hard 

bottom, and seagrass communities. 

However, because the RNA is a no anchor zone, diving will 

be concentrated at designated dive sites associated with mooring buoys. The intensity of diving activity at these sites could 

cause direct damage to corals. In addition, anchor damage to 

corals could increase at prime fishing and diving sites adjacent 

to the RNA (e.g., Bird Key Reef) if fishing and diving activity 

is effectively displaced to these sites. Also, from an ecological 

perspective, the recovery of reef fishes in the RNA following 

the elimination of fishing could have cascading effects on 

coral reef benthic communities and ecological processes.

Performance Measures

Damage to and loss of stony and soft corals species 

(Essential Activities 1 and 2 below), seagrass, benthic 

community structure, abundance of functional groups; 

measures of grazing pressure, coral recruitment, spawning, and disease; and measures of primary productivity 

(Essential Activity 3 and Supplemental Activity 1 below). 

Essential Activities 

1) Assess the effects on corals of SCUBA and snorkeling 

use at RNA designated (mooring buoy) dive sites. At least 

four dive sites and four reference sites should be sampled 

once per year. 

Mooring buoys provide an alternative to substrate-damaging 

boat anchors. Photo by FKNMS.
vi

2) Using visual methods, evaluate the ecological effects 

of fishing and dive boat anchoring on coral reefs adjacent 

to the RNA. These activities could be conducted annually 

at Bird Key Reef. 

3) Investigate trophic cascade effects on RNA coral reef 

community structure and ecological processes resulting 

from the removal of fishing activities.

Supplemental Activities

1) Assess the effects of creating the RNA no anchor zone 

on coral reef and seagrass beds. 

RNA Performance Topic 5: Assess 

reproductive potential of exploited 

species by evaluating egg production and 

larval dispersal.

Protecting populations of reef sportfish may result in 

larger, more fecund fish. Productivity of these fishes may help 

replenish sportfish populations regionally via larval transport. 

An improved understanding of reproductive and larval dispersal parameters will help inform larval transport models 

and assist in understanding of the regional benefits of RNA 

establishment. 

Performance Measures 

Fecundity and larval production of reef sportfish and 

movement of reef sportfish from the RNA to spawning 

aggregation sites. RNA export of targeted reef fishery 

species, primarily larval groupers and snappers, throughout the Tortugas and Florida Keys.

Essential Activities

1) Collect and develop population data on reef sportfish 

fecundity. Use a variety of methods inside and outside the 

RNA to develop a robust fecundity dataset for one or two 

species, representative of the snapper-grouper complex. 

2) Incorporate tagging studies to evaluate movement to 

and from spawning aggregations outside of the RNA. 

3) Implement drifter studies using spawning aggregations 

to assess regional larval export. 

4) Review and provide recommendations for expanding 

ongoing efforts to study and model larval transport. 

Supplemental Activities 

1) Expand ongoing efforts to model larval transport 

throughout the region.

2) Implement a demonstration of connectivity between 

the RNA and surrounding regions by inducing females to 

produce larvae with a unique genetic marker, possibly by 

chemical- or radiation-induced chromosome damage or 

insertion of a particular gene sequence into lab-reared 

females. 

Sailboat anchored in Dry Tortugas National Park. Photo by Brett 

Seymour, NPS.
Assessing the Conservation Efficacy of the Dry Tortugas National Park Research Natural Area vii

RNA Performance Topic 6: Incorporate 

social sciences into the research and 

monitoring program.

Given that a key component of the National Park Service 

mission is to provide for public enjoyment of the natural and 

cultural resources held within national parks and to provide 

educational opportunities, the NPS seeks to understand the 

effect of the RNA on the visitor experience. Visitors understand, appreciate, and are inspired by NPS resources; and, 

given appropriate information and education, they also tend 

to support resource protection efforts. It is expected that the 

quality of the visitor experience will be enhanced by RNA 

implementation. 

Performance Measures

Fishing activity, SCUBA and snorkeling activity (total number of SCUBA divers and snorkelers and duration in water 

for each designated dive site and reference site), number 

of boats anchoring by location, visitor satisfaction, and 

law enforcement activity and regulatory compliance rates 

(number and percentage of violations by user permit 

type). Creel survey performance measures and required 

fishing activity data are discussed under Topic 3. 

Essential Activities

1) Collect and analyze fishing, diving, and boat use data 

needed to assess the effects of RNA implementation on 

visitor use. 

2) Implement an appraisal system to characterize visitor use 

experience and views regarding RNA implementation. 

3) Monitor RNA law enforcement activity and regulation 

compliance rates by visitors, commercial operators, and 

scientific researchers on an annual basis. 

Supplemental Activities 

1) Assess the economic effects of RNA implementation 

using standard socioeconomic methods. 

Schedule of Deliverables

As established in the MOU between the FWC and the NPS, 

a jointly prepared report evaluating the performance of the 

RNA will be provided to FWC Commissioners, NPS managers, and the public at three and five year intervals.

Ranger and visitor snorkel at Fort Jefferson, Dry Tortugas National Park. Photo by Brett Seymour, NPS.
viii
Assessing the Conservation Efficacy of the Dry Tortugas National Park Research Natural Area ix

Table of Contents

Contributing Authors. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x

List of Abbreviations. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . x

Introduction. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Monitoring and Research Activities. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

RNA Performance Topic 1:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 3

Quantify changes in the abundance and size-structure of exploited species within the RNA relative to adjacent areas.

RNA Performance Topic 2: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 6

Monitor the immigration and emigration of targeted species in the RNA.

RNA Performance Topic 3:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 8

Monitor changes in species composition and catch rates of exploited species throughout the surrounding region.

RNA Performance Topic 4: . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Evaluate the effects of RNA implementation on marine benthic biological communities.

RNA Performance Topic 5:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 14

Assess reproductive potential of exploited species by evaluating egg production and larval dispersal.

RNA Performance Topic 6:. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 16

Incorporate social sciences into the research and monitoring program.

Schedule of Deliverables. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 17

Literature Cited. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 18

Appendix I. Memorandum of Understanding. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 21

Appendix II. Public Comment and Agency Response. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 31

Opposite page: NPS scientists evaluating benthic communities. Photo by Brett Seymour, NPS.
Please reference this report as follows: 

SFNRC and FWC. 2007. Assessing the Conservation Efficacy of the Dry Tortugas National Park Research Natural Area. South Florida Natural 

Resources Center, Everglades and Dry Tortugas National Parks, Homestead, FL, and the Florida Fish and Wildlife Conservation Commission, 

Tallahassee, FL. 47 pp. 

BACI Before-After-Control-Impact

CPUE Catch per unit effort

DTNP Dry Tortugas National Park

ENP Everglades National Park

ESA Endangered Species Act

FKNMS Florida Keys National Marine Sanctuary

FWC Florida Fish and Wildlife Conservation 

Commission

GMP General Management Plan

MOU Memorandum of Understanding

NCZ Natural/Cultural Zone

NEPA National Environmental Policy Act

NMFS National Marine Fishery Service

NOAA National Oceanic and Atmospheric 

Administration

NPS National Park Service

REEF Reef Environmental Education Foundation

RNA Research Natural Area

RSMAS Rosenstiel School of Marine and Atmospheric 

Science 

RVC Reef Visual Census

SDCP Stationery Diver Circular Plot

SEFSC Southeast Fisheries Science Center

SFCN South Florida Caribbean Network

SOW Scope of Work

SRS Stratified Random Sampling

TER Tortugas Ecological Reserve

TNER Tortugas Northern Ecological Reserve

TSER Tortugas Southern Ecological Reserve

USGS United States Geological Survey

List of Abbreviations

Contributing Authors

David Hallac1, John Hunt2, Douglas Morrison3, Bill Sharp4, and Robert Johnson1

1

South Florida Natural Resources Center, National Park Service, 950 N. Krome Avenue, Homestead, FL 33030

2

Fish and Wildlife Research Institute, Florida Fish and Wildlife Conservation Commission, Marathon, FL 33050

3

Florida Bay Interagency Science Center and Dry Tortugas National Park, 98630 Overseas Highway, Key Largo, FL 33037

4

Florida Fish and Wildlife Conservation Commission, Tallahassee, FL 32399

Comments and Questions: David_Hallac@nps.gov and John.Hunt@MyFWC.com 
Assessing the Conservation Efficacy of the Dry Tortugas National Park Research Natural Area 

introduction

Renowned for its cultural and natural resources, Dry Tortugas 

National Park (DTNP) lies at the western end of the Florida 

Keys along the Straits of Florida. First established as Fort Jefferson National Monument in 1935, the site was reauthorized 

in 1992 as Dry Tortugas National Park. Congress established 

the park to “preserve and protect for the education, inspiration, and enjoyment of present and future generations nationally significant natural, historic, scenic, marine, and scientific 

values in south Florida.” The enabling legislation stipulates 

that the park must be managed so as to protect, among other 

values, “a pristine subtropical marine ecosystem, including 

an intact coral reef community.” The seven islands of the Dry 

Tortugas are composed of sand, limestone, and coral reef 

fragments and are surrounded by shoals and water to depths 

of 25 m (82 ft). A significant characteristic of the park is its 

ratio of land to water; 99.8% of the park consists of marine 

ecosystems. 

This report presents a science plan developed by the 

National Park Service (NPS) and the Florida Fish and Wildlife 

Conservation Commission (FWC) that will be used to assess 

the effectiveness of the Research Natural Area (RNA) of Dry 

Tortugas National Park, established in January 2007. The 

RNA is a 46-square mile marine reserve designed to restore 

ecological integrity and capacity for self-renewal by minimizing the effects of human activities (see map of RNA on inside 

cover). The RNA complements protection afforded by the 

adjacent Tortugas Ecological Reserve (TER) of the Florida 

Keys National Marine Sanctuary (FKNMS) established by the 

National Oceanic and Atmospheric Administration (NOAA) 

and the state of Florida, and thereby contributes to a regionwide effort to strengthen resource protection. Together, the 

RNA and the larger TER will help to ensure the success of 

both marine and terrestrial ecosystems while offering outstanding opportunities for scientific research and public education (see map of the regional reserve network on the inside 

back cover). 

The goal of establishing the DTNP RNA is to protect 

shallow water marine habitat, ensure species diversity, and 

enhance the productivity and sustainability of fish populations throughout the region. Appropriate activities within the 

reserve include boating, swimming, snorkeling, scuba diving, 

hiking, research, and education. Anchoring and fishing are 

prohibited; however, mooring buoys will be provided for 

day use by snorkelers and scuba divers. No manipulation of 

resources is allowed, except as needed to accomplish restoration. The RNA provides a unique unexploited area that can 

be used to help assess the effects of fishing on exploited areas. 

Long-term studies and monitoring will serve to document 

existing baseline conditions and analyze how park natural 

resources respond to the protection provided. 

The NPS and the FWC are committed to working together 

to conduct research, education, enforcement, and adaptive 

management of the Dry Tortugas ecosystem. In February 

2007, the NPS and the FWC established a Memorandum of 

Understanding (MOU) to facilitate cooperation in the evaluation of the performance of the RNA. The MOU identifies six 

areas of RNA performance to be evaluated: 

1. Quantification of changes in abundance and sizestructure of exploited species within the RNA relative to adjacent areas; 

2. Monitoring of the immigration and emigration of 

targeted species in the RNA; 

3. Monitoring of changes in species composition and 

catch rates of exploited species throughout the surrounding region; 

4. Monitoring of species composition and abundance 

of the benthic community; 

5. Assessment of reproductive potential of exploited 

species by evaluating egg production and larval dispersal; and

6. Incorporation of social sciences into the research and 

monitoring program.

Grunts and yellowtail snappers in soft coral. Photo by Jerry Ault, 

Univ. of Miami/RSMAS.
The MOU stipulates that a monitoring and research plan 

be developed that incorporates the RNA performance areas 

described above. The MOU requires that a review and summary of past and existing work in DTNP relevant to the RNA 

be undertaken and that a schedule of deliverables for reporting be provided.

In response to the direction provided by the MOU, this 

report identifies monitoring and research activities for each of 

the performance areas. Appropriate performance measures 

are listed for each performance area, along with both essential 

and supplemental categories of monitoring and research activities. Each performance area described in the Monitoring 

and Research Activities section of this report includes a summary of relevant past and existing work in DTNP. A schedule 

for delivery of evaluation reports is provided. For reference, 

the MOU is included as Appendix I of this report.

In order to ensure that science plan activities chosen would 

be those best suited to address the marine conservation objectives of the RNA, the NPS and FWC facilitated two science 

coordination meetings. The first meeting was held to obtain 

recommendations from state and federal agency scientists on 

February 12 and 13, 2007, in Homestead, Florida. Participating 

agencies included: Florida Fish and Wildlife Conservation 

Commission, National Park Service (DTNP, South Florida 

Caribbean Network, and Water Resources Division), NOAA 

(Fisheries, National Marine Sanctuary Program, and National 

Ocean Service), and U.S. Geological Survey (USGS). Using 

the recommendations gathered, the NPS and FWC developed 

a draft science plan and distributed it to agency scientists and 

members of the public for a 30-day review period. To provide 

additional opportunities for comment and input on the science plan, a public meeting was held in Key Largo, Florida on 

May 3, 2007. The meeting was well-attended by agency scientists, representatives of nongovernmental organizations, and 

concerned citizens. Review comments were addressed in the 

writing of this document. Both the comments and FWC/NPS 

responses are provided in Appendix II.

The implementing agencies believe that the RNA will provide substantial benefits to the Tortugas region; however, the 

authors of this report also recognize that ecosystems take time 

to respond to management actions. The developers of the assessment plan have recommended a variety of indicators that 

will help evaluate benefits both in short and long time-frames. 

Natural variability in sea temperature, weather events such as 

hurricanes, and other factors can affect many of the indicators 

described in this document and thereby have the potential to 

complicate RNA assessment. We anticipate that work summarized in the first three- and five-year assessment reports 

will document only the initial ecosystem response resulting 

from the implementation of the RNA. The full benefit of the 

RNA to the Tortugas region will likely only be measurable in 

the long-term.

The science plan presented in this report is specifically 

designed to address issues related to the RNA and identified 

in the associated MOU. However, because there remain important resource issues that are not directly addressed by the 

establishment of the RNA, additional resource stewardship 

strategies are being developed to help accomplish effective 

conservation of DTNP resources. For instance, while reef 

fish and coral declines are important DTNP natural resource 

stewardship issues, RNA establishment does not directly address the root causes of coral decline. A substantial decrease 

in stony corals has occurred over the last 30 years, especially 

among the major reef forming Acropora species, now formally 

listed under the Endangered Species Act (ESA). The loss of 

stony corals has been due mostly to disease, bleaching, hypothermic events (strong cold fronts), and hurricanes. Other 

resource protection strategies will be considered to address 

coral loss. 

Resource managers will also need to assess the conservation efficacy of the newly created Special Protection Zones 

in DTNP. Special Protection Zones have been established 

in areas requiring protection from human impact, including 

areas of shallow and sensitive corals. The purpose of these 

zones is to protect and restore ESA listed species and other 

rare, at-risk species, assemblages, and habitats by providing 

maximum protection within the park. Science needs and activities for these and other natural resource stewardship issues 

not covered by the RNA MOU will be discussed in a more 

comprehensive DTNP science plan developed by the NPS. 

Diver in Dry Tortugas National Park conducting survey of fish 

and coral. Photo by Brett Seymour, NPS.
Assessing the Conservation Efficacy of the Dry Tortugas National Park Research Natural Area 

MONITORING AND RESEARCH

ACTIVITIES

This section of the science plan provides a detailed description of the monitoring and research activities associated with 

the six RNA performance areas identified in the MOU. For 

each topic, relevant performance measures are stipulated, a 

summary of past and existing work in DTNP and the region is 

provided, and anticipated essential and supplemental activities are identified. Though it may be valuable to develop quantitative targets for each performance measure, at this point, 

performance measure targets are directional and qualitative. 

Principle investigators that develop more detailed sampling 

designs should consider use of statistical techniques, such 

as power analysis, to develop sound quantitative targets. The 

first few years of study will help establish baseline variability 

in performance measures, vital to the development of quantitative targets.

RNA Performance Topic 1: Quantify 

changes in the abundance and sizestructure of exploited species within the 

RNA relative to adjacent areas.

MOU Scope of Work (SOW) A.2.a: “Expansion of ongoing 

research and monitoring program that assesses important 

reef fish populations, including the Dry Tortugas region and 

DTNP RNA. Expansion of this program shall be designed to 

provide a more robust database for examination of the performance of the RNA regarding its stated goals. The expanded 

research and monitoring program could incorporate a broad, 

multi-gear sampling approach to monitor changes in abundance and size of targeted species inside and outside RNA 

boundaries. Increases in the abundance and size-structure of 

these species in the absence of fishing mortality serve as an 

indicator that the RNA is protecting spawning biomass, agestructure, and genetic diversity that potentially enhance the 

productivity and sustainability of these species in the region.”

The primary goal of no-fishing marine reserves is to produce long-lasting increases in the abundance, size-structure, 

and productivity of target fishery species within the reserve. 

Numerous scientific studies have demonstrated that marine 

reserves can and do achieve this goal (National Academy of 

Sciences 2001, Halpern 2003, Lubchenco et al. 2003). The 

activities described below are designed to test the hypothesis 

that implementation of the RNA will enhance reef fish populations within the protected area.

Performance Measures

Abundances, sizes, occurrence frequency, and estimates 

of fisheries stock assessment parameters for groupers, snappers, and grunts inside and outside the RNA. 

Abundance of reference (non-fishery) reef fishes (e.g., 

parrotfishes).

Essential Activities

1) Implement an annual coral reef fish visual census (RVC) 

in DTNP using a stratified random sampling design (SRS) 

inside and outside the RNA. 

Previous and Existing Studies. DTNP coral reef fish monitoring, using the same visual survey methods as described 

below, was conducted in 1999, 2000, 2002, 2004, 2006, and 

will be performed in 2008 (Ault et al. 2002, Ault et al. 2006, 

Ault et al. 2007). Habitat based stratified random sampling 

was done inside and outside the RNA. Abundance, individual 

size (length), and occurrence frequency data for reef fishes, 

primarily groupers and snappers, and non-gamefish reference species (e.g., parrotfish) were collected. Ault et al. (2006, 

2007) have combined the 1999-2000 data and designated 

these the “baseline years.” Ault et al. compared park wide 

abundance data statistically for each reef fish species that 

could be analyzed. The abundance of red grouper, gray snapper, hogfish, white grunt, and blue striped grunt in DTNP did 

not change significantly between 1999-2000 and 2004. Black 

grouper, mutton snapper, and yellowtail snapper increased 

in abundance between 1999-2000 and 2004 (Ault et al. 2006). 

However, comparing 1999-2000 and 2006 data, only mutton snapper increased significantly in abundance (Ault et al. 

2007). There was no significant change between 1999-2000 

and 2006 in the abundances of all other DTNP reef fishes 

that could be analyzed (Ault et al. 2007). Ault et al. (2006) 

presented “inside RNA” and “outside RNA” abundance data 

(mean + standard error) for key reef fish and reference species 

for each year (1999-2000, 2002, and 2004); however, statistical 

analyses were not performed.

Yellowtail snapper school. Photo by Jerry Ault, Univ. of Miami/

Rosenstiel School of Marine and Atmospheric Science (RSMAS).
DTNP reef fisheries assessments, using the reef fish monitoring data described above, were performed in 2002 and 

2006 (Ault et al. 2002, Ault et al. 2006). The 2002 assessment, 

based on data gathered in 1999 and 2000, concluded that 

45% (13 of 29) of reef fish species that could be analyzed are 

over-fished; 62% (18 of 29) of fish species analyzed exceeded 

the federal fishing mortality target by two to six times (Ault 

et al. 2002). This study also concluded that the DTNP fishery for reef fishes is in worse condition than the rest of the 

Tortugas region, and that increased regional fishing pressure 

over the previous 30 years is likely an important factor in these 

declines. The 2006 assessment, based on data collected from 

1999 to 2004, concluded that over 80% of reef fish species, 

and over 90% of grouper and snapper species, that could be 

analyzed are over-fished (Ault et al. 2006). 

NOAA has conducted annual fish visual census surveys 

since 2001 at 10 sites in DTNP, four in the RNA and six in 

the natural/cultural use zone (fishing permitted), and three 

sites adjacent to DTNP where fishing is permitted (Fonseca 

et al. 2006). This monitoring is part of the NOAA Tortugas 

Ecological Reserve Biogeographic Assessment Project. These 

surveys could provide additional information for assessing 

changes in reef fishes within the RNA relative to adjacent 

fished areas.

Proposed Studies. Implementation of an annual coral 

reef fish visual census using a stratified random sampling 

design could be accomplished by adding two strata (RNA 

and non-RNA zone) to the ongoing monitoring effort, and 

increasing sampling frequency to once a year for those two 

strata. Previous NOAA Southeast Fisheries Science Center 

(SEFSC) sampling of reef fishes in the Tortugas region used a 

Stationary Diver Circular Plot (SDCP) technique (Bohnsack 

and Bannerot 1986) with goals of distinguishing spatial differences between DTNP, Fished Tortugas Bank and the Tortugas 

North Ecological Reserve (TNER), detecting biannual temporal changes within each area, and detecting reef fish changes 

for the total Tortugas sample domain. 

Sampling in DTNP used a two stage survey design that in 

2004 included 194 primary 200 x 200 m sample units and 355 

15 m diameter circular plots as second-stage units (Ault et al. 

2006). Each primary sample unit included four fish census 

dives of circular plots. In 2006, 154 primary units and 298 

second-stage units were sampled.

Detecting temporal changes and spatial differences of reef 

fish populations within the RNA and between the RNA and 

the non-RNA areas in DTNP will require appropriately stratified sampling within these zones. To ensure the same level of 

statistical power within the RNA and non-RNA zones, approximately twice the previous total number of samples will 

need to be collected annually. However, if it is determined 

that it is necessary to detect small parameter changes, then 

the increased statistical power required will necessitate larger 

sample sizes. In either case, an analysis of the actual occurrence by habitat type and spatial distribution of reef habitat 

strata within the RNA and non-RNA will be necessary to determine the optimal allocation of samples.

Previous SEFSC sampling in DTNP used a habitat strata 

classification based on the degree of patchiness and vertical 

relief. Sample allocation among strata was based on coverage 

area and variability in fish data. For comparison purposes, in 

2006 primary sampling units in DTNP were allocated among 

eight strata as follows: low relief hard bottom - 81, low relief 

spur and groove - 14, patch hard bottom in sand - 24, mediumprofile reef - 23, rocky outcrops - 24, reef terrace - 17, high-relief spur and groove - 4, and pinnacle reef - 7. If management 

desires to increase the number of habitat strata analyzed, then 

additional samples will be required. Actual sample size allocation in a monitoring plan will require a determination of the 

distribution of total habitat by type in the RNA and non-RNA. 

The final sample size allocation decision will be a compromise 

between total cost versus the desired precision of parameter 

estimates by habitat for total RNA and non-RNA zones.

Historical reef fish monitoring in DTNP focused on fixed 

sites such as “Little Africa” and “Texas Rock.” If managers 

decide that it is important to continue to monitor these sites, 

additional sampling should be considered for these locations 

in addition to the randomized stratified by habitat approach 

described above. The problem of pseudo replication should 

be considered. Multiple samples for fixed sites (especially 

small sites) may give a misleading sense of precision because 

the samples are not independent - the same fish are repeatedly sampled. In this regard collecting multiple samples on the 

same day is less desirable from a statistical perspective than 

having the same number of samples collected over a longer 

time period. In addition, since these historical sites were not 

randomly selected, the results from monitoring the sites may 

not reflect broader RNA and non-RNA trends. 

2) Employ fish traps and hook-and-line gears to collect 

additional information on selected species to evaluate 

changes in relative abundance and size-structure. At least 

initially, data should be collected three times a year. These 

efforts will also provide individual fish for use in tagging 

activities (see Topics 2 and 5).

Previous and Existing Studies. DTNP partially initiated this 

activity in 2006 in conjunction with a sonic tagging project to 

assess reef fish movement (Ault et al. 2007). Eighty-four groupers were captured in 2006; length and weight data were recorded (Ault et al. 2007). FWC recently (2007) received USGS 

funding to continue this activity for three years beginning in 

2008.

Proposed Studies. It is recommended that current research 

and monitoring efforts be expanded to incorporate passive 

sampling techniques such as baited fish traps and baited 

hook and line. Such a multi-gear approach would complement existing RVC monitoring by providing additional data 

from which abundance, frequency of occurrence, and sizestructure of selected species can be compared among three 

regions (previously-established TER no-fishing zone, newlyestablished RNA, and areas open to fishing within DTNP). 

Because the actual length of each individual will be measured 
Assessing the Conservation Efficacy of the Dry Tortugas National Park Research Natural Area 

and not estimated, this approach will allow for a more accurate comparison of size-structure of selected species. In 

addition, implementation of these gear types would provide 

individuals of selected species for use in tagging and telemetry 

studies of movement within and across RNA boundaries (see 

Topic 2 below) and biological material for life history studies 

(see Topic 5 below).

Collection of fisheries-independent data using fish traps 

and hook and line would be based upon the existing stratified 

random sampling design developed for the RVC monitoring program to maximize comparability of results. Sampling 

would occur within each of the three regions; within each 

region effort would be partitioned among habitat strata based 

on the degree of vertical relief and patchiness of hard bottom 

substrate. At each randomly-chosen sampling site, a series of 

fish traps will be deployed for a short duration (approximately 

1 hour) to reduce the likelihood of trap feeding. While traps 

are soaking, the field crew will conduct a one-hour hook and 

line survey within the same sampling grid. All individuals collected during both fish trap and hook and line surveys will be 

identified to the lowest practical taxon, measured and enumerated, while individuals of selected species will undergo 

additional processing (see Topics 2 and 5 below). During fish 

trap and hook and line surveys, physiochemical and habitat 

data will be collected at each sampling site. Additionally, for 

hook and line surveys, detailed effort data as well as specific 

catch information (e.g., bait type, hook type, hook placement, 

condition of fish upon release) will be recorded. 

SRS surveys incorporating fish traps and hook and line 

would preferably be conducted during three research cruises 

annually to examine seasonal dynamics of the reef fish community within DTNP as well as address the potential impacts 

of hurricanes and other stressors. Due to the difficult logistics 

of sampling during winter months, sampling would likely be 

restricted to a spring, summer, and fall research cruise.

Supplemental Activities

1) Conduct visual surveys of fishes in seagrass communities inside and outside the RNA. Reef fish species, especially juveniles, found in seagrass beds may be an early 

indicator of RNA success.

Previous and Existing Studies. No previous monitoring of 

reef fish species in DTNP seagrass beds has been conducted.

Proposed Studies. Reef fish species abundance and sizestructure, especially of juveniles, would be measured at depth 

stratified randomly selected seagrass sites within the RNA 

and fished areas outside the RNA — similar to the sampling 

design recommended for coral reefs (see Essential Activity 1 

above). The visual fish survey would be the SDCP technique 

(Bohnsack and Bannerot 1986) used on coral reefs (see 

Essential Activity 1 above). Seagrass plant community rapid assessments should be done at the fish survey sites (e.g., percent 

cover using the Braun-Blanquet or similar method). These 

seagrass plant community assessments would also contribute 

to Topic 4, Supplemental Activity 1. We suggest completing at 

least two surveys, one as soon as possible (because the RNA 

no-fishing zone has already been implemented), and one near 

the conclusion of the first five year assessment period.

2) Conduct seasonal coral reef visual surveys inside and 

outside the RNA to provide additional information on the 

abundance and size of reef fish.

Previous and Existing Studies. There has been no seasonal 

coral reef fish monitoring conducted in DTNP.

Proposed Studies. This activity would add seasonal monitoring (i.e., summer and winter) to Essential Activity 1 above. 

Previous visual sampling in the Florida Keys region has been 

based on annual sampling conducted in the summer to provide a consistent time frame when the weather is most predictable and conducive for conducting diving surveys. This 

approach was based on the assumption that annual sampling 

was sufficient to characterize reef fish communities since most 

reef species are long-lived (life spans on the order of years to 

decades) and exhibit high site fidelity. Previous NOAA SEFSC 

sampling in the Tortugas region was conducted biannually in 

June/July because of logistical constraints and the high expense of chartering a live-aboard diving vessel sufficient to 

carry numerous divers. Conducting sampling in the June/July 

time period ensured consistent weather for sampling and 

eliminated season as a confounding variable. 

Adding seasonal monitoring, in theory, requires obtaining 

the same number of samples for each season included. Thus, 

if two seasons (summer and winter) are considered, the total 

number of visual stations will be twice that of an annual sample, with half collected in the summer and half in winter. If 

four seasons are desired (summer, fall, winter, and spring), the 

Southeastern Fisheries Science Center (NOAA) divers beginning 

a survey. Photo by Jerry Ault, Univ. of Miami/RSMAS.
total number of samples will need to be four times as many as 

a single annual sample. However, the total cost for obtaining 

additional samples is likely to be much higher than a simple 

multiple of the summer sampling cost. Weather becomes 

more uncertain during other seasons (especially in the winter 

and spring) and fewer days are suitable for diving, extending 

the time required in the field. Options to be considered: 

1. Continue to conduct sampling once a year in late 

spring or summer as representative of annual trends. 

2. Expand directed sampling to include two seasons: 

winter and summer. 

3. Expand directed sampling to include four seasons: 

winter, spring, summer, and autumn. 

Options 2 and 3 are predicted to be disproportionately 

more expensive than summer sampling due to increased 

and unpredictable frequency of unsuitable conditions due 

to wind and turbidity. Locally chartered smaller vessels with 

fewer divers than used in the summer sampling could be used 

to take advantage of short periods of suitable weather in the 

other seasons. Nonetheless, a longer sampling period with 

more transit days would be still be required, as well as a readily available supply of trained divers. 

Little evidence exists to support the possibility that southern Florida reef fish communities change radically during a 

year, although seasonal patterns in recruitment, movements, 

or spawning may occur for some species. For example, a 

preliminary analysis of data collected by Jones, Thompson, 

and Schmidt from Biscayne National Park in the 2006 Reef 

Revisited Project did not detect significant seasonal changes 

in reef fish populations (Dr. Todd Kellison, personal communication). Another experiment comparing summer and 

winter reef fish communities in Biscayne National Park by the 

University of Miami using SDCP methodology, is in the process 

of being analyzed (Dr. S. Smith, personal communication). 

RNA Performance Topic 2: Monitor the 

immigration and emigration of targeted 

species in the RNA.

MOU SOW A.2.b: “Implementation of a variety of tagging 

studies (e.g., using acoustic tags as well as conventional darttags) to examine broad- and fine-scale movement patterns of 

targeted species in and out of the RNA. This would be accomplished by expanding ongoing collaborative acoustic tracking 

research projects as well as by conducting new studies. Such 

studies will help evaluate if adjacent fishing areas are enhanced 

through emigration of target species from the RNA.”

An intended conservation benefit and ecological effect 

of no-fishing marine reserves is that the abundance and 

size-structure of targeted fishery species should increase 

in areas adjacent to the reserve due to net emigration from 

the reserve. This ecological process is commonly called the 

spillover effect. Scientific studies on coral reef fishery species 

have demonstrated spillover effects from no-fishing reserves 

(McClanahan and Mangi 2000, Roberts et al. 2001, Galal et al. 

2002, Russ et al. 2003, Russ et al. 2004). Multiple tagging studies will be implemented to assess net movement of targeted 

reef fishes (groupers and snappers) from the RNA to adjacent 

fishing areas, and thus test the spillover effect hypothesis with 

this protected area.

Performance Measures 

Net emigration of select species from the snapper-grouper complex from the RNA to adjacent fished areas inside 

and outside DTNP.

Essential Activities

Previous and Existing Studies. DTNP implemented a pilot 

sonic and external tagging project to monitor movement of 

selected grouper and snapper species out of and into the 

RNA in 2006 (Ault et al. 2007). This study initially focused on 

movement between the RNA and NOAA TER. In 2006, only 

three of the 33 sonic tagged fished were detected moving between the RNA and TER. The low percentage of individuals 

moving between the areas may reflect the lack of contiguous 

reef habitat transversing the RNA-TER boundary where the 

study was conducted. A deep (>40 m) and wide (2-6 km) sand 

trench separates most of the RNA and TER reef habitat in 

this area. This project is being expanded in 2007 to assess net 

movement of grouper and snapper species from the RNA to 

adjacent fishing areas.

FWC recently (2007) received USGS funding to implement a spatially extensive sonic and external tagging project 

to assess net emigration of groupers and snappers from the 

RNA to adjacent fishing areas. This three year project will 

begin in 2008. School of grunts in Dry Tortugas National Park. Photo by Douglas 

Morrison, NPS.
Assessing the Conservation Efficacy of the Dry Tortugas National Park Research Natural Area 

1) Implement a sonic tagging study to monitor broad 

scale net emigration patterns of selected species from 

the RNA to fished areas in the DTNP region. The study 

area will encompass the Florida Shelf of the DTNP region 

and consist of open fished areas (Natural/Cultural Zone 

(NCZ), DTNP and Florida Keys National Marine Sanctuary 

(FKNMS) waters south of the DTNP to Rebecca Shoals 

(15 km east of DTNP), and regulated marine protected 

areas (RNA, Tortugas South Ecological Reserve (TSER) and 

Tortugas North Ecological Reserve (TNER)). 

Proposed Studies. Sonic tags will be used to monitor broad 

scale immigration/emigration or flux of selected species from 

the RNA to fished areas throughout the DTNP region, with a 

focus on evaluating diel patterns of habitat use and identifying core utilization areas (home range). Samples will be collected using a SRS design. Broad scale movement studies will 

complement and be combined with fine scale acoustic studies 

currently being conducted along the northwest border of the 

RNA. The study area will encompass the Florida Shelf of the 

DTNP region and consist of open fished areas (NCZ, DTNP, 

and FKNMS waters south of the DTNP to Rebecca Shoals 

[15 km east of DTNP]) and regulated marine protected areas 

(RNA, TSER, and TNER).

Fifty acoustic Vemco VR2 receivers will be placed around 

and within the designated zones of the DTNP region. Zones 

will be classified into three categories: no-fishing zones (RNA, 

TSER, and TNER), DTNP, and FKNMS. Within these zones 

habitat will be classified by depth (0-10, 10 – 30, 30 – 60 m) and 

substrate (patchy hard bottom in sand, low relief hard bottom 

in sand, medium profile reef, low relief spur and groove, high 

relief spur and groove, reef terrace and pinnacle). Receivers 

will be anchored to the bottom with a 75 lb down weight attached to subsurface buoys and mounted on 2” x 3’ PVC pipe. 

The receivers will be placed within the designated zones near 

capture and release sites and along bathymetric strata that 

approximate the sanctuary and park boundaries. Data will 

be downloaded tri-annually (early spring, summer, and late 

fall) with Vemco software requiring three boat trips per year. 

Downloading efforts will require four working days with a 

team of four personnel.

Individuals of targeted species will be surgically implanted 

with Vemco acoustic pinger tags (V13 and V16) and external 

anchor tags. Samples will be collected by directed fishing efforts for targeted species with the assistance of a commercial 

fisher. In addition, fish will be captured and tagged in conjunction with the fishery independent SRS efforts using fish 

traps (Topic 1, Essential Activity 2). A total of 120 fish will be 

acoustically tagged (60 each year). Fishing trips will be coordinated with the acoustic data retrieval trips and SRS trips. 

Fishing efforts will require 5 working days with a team of four 

personnel. Each combined tri-annual trip to the DTNP will 

encompass a total of 9 working days plus 2 travel days.

2) Use external tags on selected species to monitor broadscale net emigration patterns from the RNA to fished areas 

in the DTNP region. Recaptured individuals should then 

be identified from subsequent sampling events as well 

as from reports made by recreational anglers to the FWC 

Fish and Wildlife Research Institute tag return hotline. 

Proposed Studies. Fish tagging will be conducted in conjunction with SRS surveys. Three research cruises are planned 

every year to examine the seasonal dynamics of reef fish communities within DTNP. The tagging projects are designed to 

track broader scale fish movements throughout the region 

and over time. In addition to movement information, the tagging program will also monitor fish survival within DTNP. 

The key to determining habitat range and monitoring survival 

is to maintain a consistent flow of tags going out into the fish 

population; this means continued tagging for a number of 

years with ongoing updates on survival estimates. It takes at 

least three tagging sessions to derive the first estimate of survival. With each subsequent tagging session, the survival estimate is extended an additional year. The premise underlying 

this monitoring tool is the probability of recapturing tagged 

fish. This approaches provides, and relies on, outreach to the 

recreational fishing community.

Methods: Conventional tagging techniques will be used 

during the SRS monitoring component to record fish movements and fish survival, within the three sampling regions 

(previously-established Marine Protected Area in TNER, 

newly-established RNA, and open-use areas within DTNP). 

All individuals of exploited species that are to be released alive 

will be tagged using conventional external tags prior to release. Recaptured individuals will then be identified from subsequent sampling events as well as reports from recreational 

anglers made to the FWC Fish and Wildlife Research Institute 

tag return hotline (1-800-367-4461). Information advertising the tagging program will be distributed throughout the 

Florida Keys and DTNP and will be published in local newspapers. Double and triple color-coded tags are now available 

to support a large number of individual identification codes. 

These tags will allow divers and snorkelers to report sightings 

without having to catch the fish. 

Goliath grouper in Dry Tortugas National Park. Photo by Douglas 

Morrison, NPS.


The possibility of tag loss must be addressed in any monitoring program involving fish tagging. Survival estimates can 

appear artificially low if tag loss is not taken into account. 

Double tagging of individual fish allows for assessment of 

tag loss. This approach can be achieved through the application of two numbered tags or one numbered tag combined 

with a dorsal fin clip. In either case, the loss of numbered tags 

can be estimated. There are other approaches available, such 

as Passively Integrated Transponder tags, but they are more 

expensive.

Public Outreach: It is important to develop a high quality 

tagging program utilizing recreational anglers to enhance data 

collection efforts. Information advertising the tagging program and educating fishers and anglers about how to respond 

if they catch a tagged fish will be distributed throughout the 

Florida Keys, the DTNP, and other parks in south Florida. 

This information will also be published in local newspapers. 

Cooperation and participation from a wide range of fishers 

and divers is the key to the success of our tagging effort.

Supplemental Activities

1) Expand sonic tagging to examine immigration and emigration from the RNA to the TSER. 

Proposed Studies. Test the hypothesis that fish move from 

foraging grounds (RNA, DTNP, and TNER) to spawning areas. Understanding population connectivity, spawning migratory movements, reproductive potential, and spillover in the 

DTNP region is critical to the assessment of the effectiveness 

of existing Tortugas no-fishing zone boundaries.

2) Expand sonic tagging to examine immigration and emigration from the RNA to the TNER. 

Proposed Studies. Understanding population connectivity, 

spawning migratory movements, reproductive potential, and 

spillover in the DTNP region is critical to the assessment of the 

effectiveness of existing Tortugas no-fishing zone boundaries.

RNA Performance Topic 3: Monitor 

changes in species composition and catch 

rates of exploited species throughout the 

surrounding region.

MOU SOW A.2.c: “Development of a fisheries-dependent 

monitoring program to evaluate potential changes in catch 

rates, species composition, and size composition of commercial and recreational fisheries in areas surrounding the RNA. 

This program could use a variety of data collection methods 

including on-board observers, logbooks, aerial surveys, and 

recreational fisheries interviews.”

One purpose of establishing no-fishing marine reserves, 

such as the RNA, is to enhance fisheries in areas proximate to 

the no-fishing zone. Recent scientific studies of coral reef fisheries have shown that marine reserves have enhanced adjacent 

fisheries, as measured by greater fish biomass (more and/or 

larger fish), greater catch, increased catch rate, and reduced 

fishing effort (McClanahan and Mangi 2000, Roberts et al. 

2001, Galal et al. 2002, Russ et al. 2003, Russ et al. 2004). NPS 

and FWC will develop and implement a fisheries-dependent 

monitoring program to assess the effects of RNA implementation on recreational and commercial fisheries in fishing areas 

surrounding the RNA. Recreational fishing activity in DTNP 

will be monitored using private angler creel and charter fishing boat logbook surveys. Note: Commercial fishing has 

been prohibited in DTNP since 1935. This information will 

also contribute to targeted fishery species stock assessments. 

Existing Tortugas recreational and commercial fisheries dependent monitoring programs will be used to evaluate the 

effects of RNA implementation on fisheries outside DTNP.

Performance Measures 

Catch per unit effort (CPUE), including released fish, harvest per unit effort, estimated total catch and harvest, 

and population size-structure of targeted reef fishery species, especially grouper and snapper species, throughout 

the Tortugas region.

Essential Activities

1) Design and implement an angler creel survey in fished 

areas within DTNP (survey conducted by fixed intercept at 

Garden Key, roving patrol, and via the visitor use permit 

system). This survey should record catch per unit effort 

and sizes of reef fish caught.

Previous and Existing Studies. DTNP private boat recreational fishing activity (creel survey) data were collected from 

1981-1984 and 2000-2004. Ault et al. (2006) analyzed these 

data for historical trends. Grunt and gray snapper CPUE Nassau grouper, federal species of concern. Photo by Douglas 

Morrison, NPS.
Assessing the Conservation Efficacy of the Dry Tortugas National Park Research Natural Area 

declined between the two time periods; whereas, yellowtail 

snapper and grouper CPUE increased substantially. Creel 

results suggest that DTNP gray snapper abundance might be 

undergoing a long term decline. The decrease in grunt CPUE 

coupled with a decline in trips that caught grunts might indicate that grunt fishing intensity has been increasing in the park 

over the last 20 years.

Proposed Studies. A traditional creel census project will 

collect DTNP recreational fishing activity data from private 

boat anglers using access point intercept interviews conducted at the Garden Key and roving on-water interviews. 

Data recorded include fished species composition (emphasizing grouper, snapper, and grunt species), area fished (three 

fished zones: the Adaptive Use Zone, one nautical mile radius 

around Garden Key; the Natural Cultural Zone east of the 

RNA; and the Natural Cultural Zone west of the RNA), fish 

kept and released by species and zone, fish length by species, 

fishing effort (number of anglers multiplied by hours fishing), 

species preference, and angler residence. 

The proposed DTNP visitor use permit system will require 

all private boat anglers to obtain a permit. Anglers could be required to provide fishing activity data as a component of this 

permit system. Anglers would be provided with survey forms 

when obtaining their permits. Anglers would be required to 

return completed surveys either at Garden and Loggerhead 

Keys, by US mail, or via the internet. This data collection 

technique could be as, or more, effective than the interview 

methods described above. This survey method should be developed, initiated, and evaluated when the new permit system 

is implemented. 

2) Collect DTNP permitted charter boat recreational fishing data via a logbook system.

Previous and Existing Studies. DTNP charter boat recreational fishing activity surveys using a logbook system began 

in 2005. No catches were reported in 2005. Thirty-four trips 

were reported in 2006 and five trips thus far in 2007. The most 

common reef fishes caught were yellowtail snapper and red 

grouper.

Proposed Studies. All professional charter and guide boats 

operating in DTNP are required to obtain annual permits. 

These operators are required to provide monthly reports of 

the catch and effort for each fishing trip using logbooks supplied with their permits.

3) Review and utilize data from existing Tortugas recreational and commercial fisheries dependent monitoring 

programs to evaluate the effects of RNA implementation 

on fisheries outside DTNP.

Previous and Existing Studies. There are several existing 

Tortugas recreational and commercial fisheries dependent 

monitoring programs. Fishing activity by “head boats” has 

been collected by the National Marine Fisheries Service 

(NMFS) since 1981 using a logbook system. FWC initiated 

an on-board observer head boat survey program in 2005. 

A cooperative federal-state Fisheries Information Network 

(Gulf States Marine Fisheries Commission/FWC/NMFS) 

head boat survey is underway which will compare results 

from the NMFS and FWC programs. Tortugas charter boats 

report their fishing data via logbooks to the NMFS Charter 

boat Survey Program. 

Tortugas commercial fisheries data are collected through 

the NMFS Florida commercial fisheries trip ticket program. 

Catches for most Tortugas commercial fisheries have declined 

over the past decade.

Proposed Studies. There are several recreational and commercial fisheries dependent monitoring programs that collect data from the Tortugas region. Recreational charter boat 

data in the Florida Keys/Gulf Coast are gathered through the 

Cooperative Gulf Charter Boat Survey Research Program administered in the SE Gulf Region by the state of Florida and 

Gulf States Marine Fishery Commission in cooperation with 

the NMFS. There is also a pilot logbook/telephone survey 

underway to determine which is the best method to estimate 

total effort (number of trips/anglers/hours fished) and angler 

catches. These are side-by-side survey comparisons with the 

current method used by the NMFS Marine Recreational 

Fishery Statistics Survey. The method deemed the best of the 

above alternatives will be implemented to assess charter boat 

fishing activity in the Tortugas. Tortugas commercial fisheries 

data will be compiled from federal and state commercial landings and logbook data collection programs that include the 

Tortugas Region.

Supplemental Activities

1) Estimate overall fishing activity in DTNP using the park 

visitor use permit system and/or aerial surveys. 

Yellowtail snapper. Photo by Jerry Ault, Univ. of Miami/RSMAS.
10

Previous and Existing Studies. No studies have estimated 

overall fishing activity in DTNP.

Proposed Studies. The proposed DTNP visitor use permit system will require all private boat anglers to obtain a 

permit. Anglers could be required to provide fishing activity 

data through this permit system. Anglers would be provided 

with survey forms when obtaining their permits and would 

be required to return completed surveys either at Garden and 

Loggerhead Keys, by US mail, or via the internet. This method 

should be developed, initiated, and evaluated when the new 

permit system is implemented.

If the proposed permit system data collection technique is 

not feasible, then an aerial survey method should be designed 

and implemented. Aerial survey design should be similar 

to those conducted elsewhere (e.g., the current Everglades 

National Park (ENP) marine fishing boat surveys). The aerial 

survey technique provides less comprehensive data and is 

more costly than fishing activity surveys via the permit system. 

Visual surveys from Fort Jefferson could be conducted but 

these would likely be effective only for the Adaptive Use Zone, 

the one nautical mile radius around the fort.

2) Conduct aerial surveys of fishing activities in the 

Tortugas region.

Previous and Existing Studies. We have no knowledge of 

previous aerial surveys of fishing activities in the Tortugas 

region. 

Proposed Studies. Aerial survey design should be similar 

to those conducted elsewhere (e.g., the current ENP marine 

fishing boat surveys). 

RNA Performance Topic 4: Evaluate the 

effects of RNA implementation on marine 

benthic biological communities.

MOU SOW A.2.d: “Increasing the number of benthic monitoring stations to include specific sites to evaluate the impacts 

of RNA mooring buoy visitor activities and fishing and boating effects in the Dry Tortugas. Measures of benthic community change and condition will be used to assess the impacts of 

diving and snorkeling activities in the RNA.” 

RNA implementation potentially could have a variety of 

effects on coral reef benthic, and perhaps even seagrass, communities. Because the RNA is a no anchor zone, diving will 

be concentrated at designated dive sites with mooring buoys. 

Frequent diving activity at these sites could cause damage to 

corals, as has been documented elsewhere. Anchor damage to 

corals could increase at prime fishing and diving sites adjacent 

to the RNA (e.g., Bird Key Reef) as a result of increased fishing 

and diving activity at these sites. 

The recovery of reef fishes in the RNA after eliminating 

fishing could have cascading effects on coral reef benthic 

communities and ecological processes. Prohibiting anchoring 

in the RNA should greatly reduce or eliminate anchor damage 

to coral reef, other hard bottom, and seagrass communities. 

Science activities to assess these potential ecological effects 

are discussed below.

Performance Measures

 The resource stewardship target or objective is to have no 

long term effects on corals from diving or boat anchoring 

Aerial photo of Bush Key and Fort Jefferson on Garden Key. Photo by Brett Seymour, NPS.
Assessing the Conservation Efficacy of the Dry Tortugas National Park Research Natural Area 11

activities. The primary performance measures are damage and loss of branching, foliose, and plating stony coral 

species, especially ESA listed Acropora species. Secondary 

performance measures are damage and loss of sponges, 

branching soft corals and head type stony coral species. 

Stony coral species with branching morphology (e.g., 

Acropora and Porites species) are most susceptible to 

damage by diving activities (Hawkins and Roberts 1992, 

Harriott et al. 1997, Rouphael and Inglis 2002). Acropora

species are now rare in DTNP and thus are at highest risk. 

Foliose and plating stony corals (e.g., Agaricia species) 

are more susceptible than branching soft corals and head 

type stony corals (e.g., Montastrea species). Damage can 

be measured as the percentage and/or number/area of 

coral branches and/or colonies broken and abraded. Loss 

can be assessed by measuring changes in live coral percent cover. 

Changes in the following key ecological attributes: 

Comprehensive coral reef benthic community structure; 

abundances of key species and functional groups, including stony and soft corals, sea urchins, especially Diadema, 

algal functional groups, and sponges. Herbivore grazing 

intensity; direct measures of fish grazing (e.g., bites/area/

time); indirect measures of sea urchin grazing, especially 

Diadema (abundance/density). Coral recruitment and mass 

spawning. Coral disease and bleaching incidence; needed 

to differentiate effects of no-fishing from these important coral stressors. Benthic primary productivity. Target 

and non-target fish species and assemblage performance 

measures from Topic 1 (abundances and individual size of 

key fish species and functional groups).

The resource stewardship target or objective is ecological recovery of RNA coral reefs and seagrass beds from 

any previous anchor damage. Changes in the abundances 

(percent cover) of stony and soft corals, sponges, and 

seagrass. 

Essential Activities

1) Assess the effects on corals of SCUBA and snorkeling 

use at RNA designated (mooring buoy) dive sites. At least 

four dive sites and four reference sites should be sampled 

once per year. 

Previous and Existing Studies. There are no previous assessments of the ecological effects of diving on DTNP coral reefs. 

Preliminary baseline data are being collected at DTNP coral 

reef monitoring sites that will likely serve as reference sites for 

the RNA designated dive sites. The National Environmental 

Policy Act (NEPA) process for selecting RNA coral reef dive 

sites is ongoing; no mooring buoys have been installed yet.

Proposed Studies. Because boat anchoring is not permitted in the RNA, SCUBA diving and snorkeling activities in the 

RNA will be concentrated at designated dive sites with mooring buoys, and the designated Loggerhead Key swim areas. 

Multiple assessments from around the world have found that 

heavy diving activity, in most cases greater than 5,000-6,000 

divers per year per site, on coral reefs have damaged corals 

(Harriott et al. 1997, Hawkins and Roberts 1997, Hawkins 

et al. 1999, Rouphael and Inglis 2002, Zakai and ChadwickFurman 2002). Generally, at sites with less than 5,000 divers 

per year diver impacts are minimal or undetectable compared 

to undived control sites. Most studies recommend a diver carrying capacity of 5,000-6,000 divers per year per site.

Monitoring potential effects on corals of diving activity at 

DTNP designated dive sites is needed. However, initially a focused assessment project, described below, is recommended 

for the following reasons: 

Near term diving activity at almost all DTNP dive sites will 

probably be less than 5,000 divers/year; hence, diver damage is likely to be minimal at most sites, especially relative 

to other stressors. Furthermore, the carrying capacity for 

DTNP reefs might be higher than 5,000-6,000 because 

DTNP reefs are dominated by head and soft corals. Most 

impact assessments have been done on reefs dominated by 

branching stony corals which are more susceptible to diver damage than head type stony corals and soft corals (see 

below). An assessment conducted on soft coral dominated 

reefs recommended an annual limit of 7,000 dives per site 

(Schleyer and Tomalin 2000).

Anticipate the need to continue comprehensively assessing 

coral reef “health” and the effects of known major stressors, such as disease and bleaching, on coral communities. 

Scientific Approach/Methods: Damage and loss within 

the entire stony and soft coral assemblage at the three or four 

coral reef dive sites projected to have the most dive activity 

will be assessed annually for at least five years. Such a comprehensive assessment at all sites is cost prohibitive. Damage and 

loss of Acropora species will be surveyed annually at all dive 

sites. A fully replicated Before–After-Control–Impact (BACI) 





White grunts and gray snapper around diseased elkhorn coral. 

Photo by William Perry, NPS.
12

sampling design (Green 1979, Underwood 1992) should be 

used to measure and compare contemporaneous changes at 

dive sites and equivalent reference reef sites with no or little 

diving activity. Baseline conditions need to be defined before 

dive sites are implemented. Statistically significantly greater 

damage at a dive site than its corresponding reference site 

will indicate diver damage. Coral damage and loss will be 

measured using a combination of scientifically accepted direct visual and photographic methods. Ideally surveys should 

be conducted in May and October to best differentiate diver 

damage from natural disturbance. Diving activity is greatest 

and the frequency of wave induced disturbance is usually lowest during this period. However, surveys will more likely be 

conducted once a year because of funding limitations. Diver 

use data will be obtained through the DTNP permit system 

(Topic 6, Essential Activity 1).

2) Using visual methods, evaluate the ecological effects 

of fishing and dive boat anchoring on coral reefs adjacent 

to the RNA. These activities could be conducted annually 

at Bird Key Reef. 

Previous and Existing Studies. There are no previous 

DTNP ecological assessments directly related to this activity. 

Preliminary baseline data are being collected at the DTNP 

coral reef monitoring site that will serve as the reference site 

for this activity.

Proposed Studies. Fishing boats commonly anchor along 

the boundary of many no-fishing zones (e.g., FKNMS Special 

Protected Areas). The intensity of fishing and dive boat anchoring adjacent to the RNA might become great enough at 

some locations to impact coral reef benthic communities. The 

most likely location for this to occur is on the part of Bird Key 

Reef in the Adaptive Use Zone (anchoring permitted). Fishing 

and diving activities, and thus anchoring, will likely increase 

here because this reef is prime reef fish habitat adjacent to the 

RNA, is a prime dive site that will not be limited by mooring 

buoy availability, and is the reef closest to Garden Key. The 

potential for recreational use-caused coral damage here could 

be greater than that at any dive site within the RNA. Therefore, 

we propose assessing the effects of boat anchoring on the 

coral reef benthic community on Bird Key Reef adjacent to 

the RNA. This project will be integrated with the diver effects 

on corals assessment project described above.

Scientific Approach/Methods: Damage and loss to all stony 

coral, soft coral, and sponge species will be assessed annually 

for at least five years on the section of Bird Key Reef adjacent 

to the RNA (anchoring and diving allowed) and two types of 

reference sites on Bird Key Reef in the RNA. One reference 

site will be at a mooring buoy dive site (no anchoring, but 

diving occurring). The other reference site will be sufficient 

distance from a mooring buoy so that there will likely be no 

diving (and, no anchoring). This design should help differentiate anchor effects from diving effects. Baseline conditions 

need to be defined before anchoring in the RNA is prohibited. 

Coral and sponge damage and loss will be measured using a 

combination of scientifically accepted direct visual and photographic methods. Recreational boat anchoring and diver 

use data will be obtained through the DTNP permit system 

(Topic 6, Essential Activity 1). 

3) Investigate trophic cascade effects on RNA coral reef 

community structure and ecological processes resulting 

from the removal of fishing activities.

Previous and Existing Studies. The USGS recently (2007) 

funded a research project, “Coral-Algal-Herbivore Interactions 

in Protected versus Unprotected Reef Ecosystems,” to investigate trophic cascade effects on coral reef ecosystems in nofishing marine reserves, including the DTNP. This project has 

a conceptual approach very similar to that presented under 

Proposed Studies below.

The NPS South Florida Caribbean Network (SFCN) has 

recently (2007) established coral reef and other hard bottom 

benthic monitoring sites inside and outside the RNA which 

may contribute to this activity.

Proposed Studies. Over-fishing of large carnivorous fishes 

can have indirect effects on the abundances of non-target species, benthic community structure, and food web dynamics; 

a process called trophic cascade (Pauly et al. 1998, Russ and 

Alcala 1998, Dulvy et al. 2004, Sala et al. 2004, Mumby et al. 

2006). Fishing first focuses on large carnivores, resulting in 

NPS divers conducting coral surveys. Photo by Brett Seymour, 

NPS.
Assessing the Conservation Efficacy of the Dry Tortugas National Park Research Natural Area 13

a disproportionate loss of top predators from the ecosystem 

(Pauly et al. 1998). More intense fishing and fishing of widerscope, especially using small mesh fish traps, has depleted 

smaller carnivorous and larger herbivorous and omnivorous 

reef fishes in multiple locations in the tropical western Atlantic 

(e.g., Garrison et al. 1998, Wolff et al. 1999). The consequences 

of these trophic shifts can cause fundamental changes in marine ecosystem structure and function. Establishing no-fishing marine reserves should help restore more natural benthic 

community structure and ecological processes (Mumby et al. 

2006).

DTNP has not experienced the intensity and breadth of 

fishing pressure (e.g., fish trap use and spear fishing) as other 

places in the tropical western Atlantic. Thus, we would not 

expect as rapid or perhaps extensive trophic cascade response 

to RNA implementation as in these other locales. It is unlikely 

that trophic cascade effects in the RNA could be detected in 

the first five years after establishment. However, monitoring 

and research are needed in the next three years to establish 

baseline conditions to ascertain any future trophic cascade effects on DTNP coral reefs. DTNP could serve as an important 

information source for assessing the effects of no take marine 

reserves on reef food webs and community structure over a 

broader fishing pressure gradient and geographic scale. 

Scientific Approach/Methods: Establish baseline conditions by collecting data on the above key ecological attributes 

at sites representative of the major reef benthic community 

types within the RNA and corresponding reference sites outside the RNA as soon as possible. Monitoring should be conducted annually to establish baseline conditions and assess 

trophic cascade effects. This project would require key fish 

species and functional group data from, and thus be coordinated with, Topic 1 projects. 

An additional, complementary approach is focused research through a competitive proposal request process, similar to the current USGS State Partnership Program “Role of 

Marine Reserves in Florida and the U.S. Virgin Islands” research initiative. In fact, this USGS program recently funded 

a research project, “Coral-Algal-Herbivore Interactions in 

Protected versus Unprotected Reef Ecosystems,” to investigate trophic cascade effects on coral reef ecosystems in nofishing marine reserves, including DTNP. 

Supplemental Activities

1) Assess the effects of creating the RNA no anchor zone 

on coral reef and seagrass beds. 

Previous and Existing Studies. The existing DTNP seagrass 

community monitoring and assessment project can be used 

to assess the effects on seagrass beds of creating the RNA no 

anchor zone. This project, which began in 2005, has shallow 

seagrass monitoring sites inside and outside the RNA.

The SFCN recently established coral reef benthic monitoring sites inside and outside the RNA that can be used to 

assess the effects on coral reefs of creating the RNA no anchor 

zone.

Proposed Studies. RNA implementation creates a no anchoring zone covering 46% of the park. This action should 

greatly reduce or eliminate any anchor damage to coral reef 

benthic, other hard bottom, and seagrass communities in the 

RNA.

Scientific Approach/Methods: Annual benthic monitoring at randomly (perhaps stratified) selected coral reef and 

seagrass sites inside and outside (reference sites) the RNA. A 

fully replicated BACI assessment design should be employed. 

Baseline conditions need to be defined before anchoring is 

prohibited. Percent cover of key benthic ecological attributes 

will be measured using a combination of scientifically accepted direct visual and photographic methods. Currently, there 

is no means to effectively collect pre-implementation boat 

anchoring data. Post-implementation boat anchoring data at 

reference sites outside the RNA will be obtained through the 

proposed park permit system (Topic 6, Essential Activity 1). 

NPS scientists evaluating benthic communities. Photo by Brett 

Seymour, NPS.
14

RNA Performance Topic 5: Assess 

reproductive potential of exploited 

species by evaluating egg production and 

larval dispersal.

MOU SOW A.2.e: “Expansion of ongoing efforts to track 

and model larval movement patterns within the Tortugas 

and Florida Keys region from important reef fish and other 

aquatic species to evaluate larval recruitment of several finfish 

species in the south Florida region.” 

A hypothesized spillover effect of no-fishing marine reserves refers to a broad-scale, regional replenishment of target 

fishery species via larval transport from the reserve. There is 

scientific evidence that reserves enhance populations regionally through greater larval production and export due to increased fecundity of organisms within reserves (Lubchenco 

et al. 2003). Drifter studies simulating larval transport have 

found that reef fish larvae spawned in the Tortugas could be 

viably dispersed as far as Cape Canaveral on the Atlantic coast 

and Tampa Bay on the Gulf coast (Burke et al. 2003). The 

activities proposed below will test this broad-scale spillover 

effect hypothesis with the RNA. 

Performance Measures

Fecundity and larval production of reef sportfish and 

movement of reef sportfish from the RNA to spawning 

aggregation sites. RNA export of targeted reef fishery 

species, primarily larval groupers and snappers, throughout the Tortugas and Florida Keys.

Essential Activities

1) Collect and develop population data on reef sportfish 

fecundity. Use a variety of methods inside and outside the 

RNA to develop a robust fecundity dataset for one or two 

species, representative of the snapper-grouper complex. 

Previous and Existing Studies. We have no knowledge of 

studies currently collecting population data on reef fishery 

species fecundity in the Tortugas region. 

Proposed Studies. Collect biological material to compare 

the effects of fishing pressure and/or protection on the agestructure, size at age, sex ratio, and reproductive condition 

of selected species. This information could be collected in 

association with SRS monitoring using fish traps and hook 

and line (Topic 1) and creel surveys (Topic 3); and thus, would 

likely not require additional field sampling. Biological sampling will employ non-lethal methodologies (e.g., collection 

of spines/rays, gonad biopsies) to the greatest extent possible to determine age and sex of selected species. Traditional 

methodologies (e.g., ageing using otoliths, full reproductive 

workup) will be conducted on all individuals sampled during 

creel surveys to validate age data as determined via non-lethal 

methodologies and to conduct a detailed study of reproductive condition and fecundity. Since creel data will not be available from within TNER and the RNA, a limited number of 

individuals collected within these regions will be sacrificed to 

provide fecundity estimates, although this sampling will likely 

be restricted to known spawning seasons only. 

2) Incorporate tagging studies to evaluate movement to 

and from spawning aggregation sites outside the RNA. 

Previous and Existing Studies. The Tortugas region is an important spawning area for groupers and snappers (Lindeman 

et al. 2000, Lindeman et al. 2001, Ault et al. 2002, Burton et 

al. 2005). Numerous Tortugas spawning aggregation sites have 

been identified. Mutton snapper spawning aggregations increased in the no-fishing TSER after its establishment (Burton 

et al. 2005). However, there have been no studies investigating 

movement between no-fishing Tortugas foraging grounds (the 

RNA and TNER) and spawning aggregation sites.

Proposed Studies. Use sonic tags to evaluate movements 

of selected species from the RNA and the TSER to spawning aggregation sites. Use sonic tags to evaluate movements 

of selected species from the RNA and the TNER. Testing 

the hypothesis that fish move from foraging grounds (RNA, 

DTNP and TNER) to spawning areas is essential to this study. 

Understanding population connectivity, spawning migratory movements, reproductive potential and spillover in the 

DTNP region is critical to the assessment of the effectiveness 

of existing no-fishing zone boundaries.

A total of 20 fish per year will be caught (hook and line) and 

tagged at Riley’s Hump, a reef promontory within the TSER 

and a documented spawning area for numerous reef fish species. An array of 10 receivers will be placed around the reef, 

with coverage emphasized on the south edge of the reef. Fish 

will be surgically implanted with Vemco acoustic tags (V16P 

& V13P) and subsequently released at the study site. These 

tags have an expected battery life of 1,150 days and include 

a pressure sensor to determine depth. In addition, each fish 

will be measured, sexed, and anchor tagged. A biopsy sample 

of the ovary (surgical tubing cannulation) will be preserved 

in 90% ethanol to determine mean oocyte diameter. It is anticipated that fish will have to be vented rapidly upon capture 

with a 10 gauge hypodermic needle to deflate the swim bladder. Two five-day trips per year will be required near the full 

moon phase with a team of four people (May/June). Data on 

broad-scale movements to and from the aggregation site, residence time in the aggregation, and depth will be determined. 

This work will complement and be integrated with the acoustic tagging project described in Topic 2 above and NOAA research on spawning aggregations of Lutjanus analis at Riley’s 

Hump (Burton et al. 2005).

3) Implement drifter studies using spawning aggregations 

to assess regional larval export. 
Assessing the Conservation Efficacy of the Dry Tortugas National Park Research Natural Area 15

Previous and Existing Studies. Drifter studies simulating 

larval transport have found that reef fishery species larvae 

spawned in the Tortugas could be viably dispersed as far as 

Cape Canaveral on the Atlantic coast and Tampa Bay on the 

Gulf coast (Lee et al. 1994, Lee et al. 1999, Burke et al. 2003, 

Domeier 2004). Drifter studies conducted in 1999 and 2000 

indicated that a snapper spawning aggregation site on Riley’s 

Hump in TSER is a recruitment source for a broad expanse of 

southeast Florida, including the entire Florida Keys (Domeier 

2004).

Proposed Studies. The deployment of drifters within the 

RNA can help to determine the fate of larvae from commercially, recreationally, and ecologically important species of 

finfish and invertebrates. In this regard, drifter studies can be 

used to evaluate larval dispersal and establish if the RNA is 

acting as a source of recruits to the Florida Keys and/or the 

rest of Florida. Drifter studies do have certain limitations: they 

serve as “snapshots” of conditions at the time of the study, trajectories and time spent in the water before recovery are only 

estimates, and it is assumed that the larvae they mimic behave 

as passive particles (an assumption not true for many marine 

larvae). Therefore, drift vial recovery information should 

be coupled with existing hydrodynamic and larval dispersal 

models. Additionally, if retention and self-recruitment are important parameters to consider, we recommend that drogue 

studies be incorporated into the plan.

Release sites should be based on the existence or identification of spawning aggregations. Releases should occur during 

peak spawning times. For example, gag grouper in the Gulf of 

Mexico have a peak spawning period during March (South 

East Data Assessment and Review 2006), whereas red grouper spawn during both April-May and September-October 

(Collins et al. 2002). Therefore, releases should be tailored to 

the species of interest.

We recommend that 1,000 scintillation vials (clear glass 

with polyethylene caps) be deployed per release. The drift vials should be neutrally buoyant and sit just below the water 

surface to reduce the influence of wind. A note on waterproof 

paper, printed in English and Spanish, should be placed inside 

the vial with instructions for the finder to e-mail or call a tollfree telephone number to report the date, location, and the 

unique alphanumeric code identifying the vial’s place of release. Prior to deployment, press releases should be provided 

to local news sources to promote public awareness of the experiment. To encourage people to report recoveries, rewards 

can be offered.

The design of the drifters should minimize incidental 

impacts to sea life (e.g., turtles), but should also enhance the 

chances of being recovered. To this end, we recommend the 

drifters be made of clear glass with the bottom of the vials 

painted blue to camouflage them to sea life.

4) Review and provide recommendations for expanding 

ongoing efforts to study and model larval transport. 

Previous and Existing Studies. There have been multiple interdisciplinary studies on Tortugas reef fishery species larval 

production and transport (Lee et al. 1994, Limouzy-Paris et al. 

1997, Lee et al. 1999, Lee and Williams 1999, Lindeman et al. 

2000, Lindeman et al. 2001, Burke et al. 2003, Domeier 2004, 

Yueng et al. 2004, Burton et al. 2005). There have been several efforts to model Tortugas reef fishery species larval transport (Lee et al. 1994, Lee et al. 1999, Lee and Williams 1999, 

Lindeman et al. 2001, Yueng et al. 2004). The Tortugas area 

is a principal reef fishery species recruitment source for the 

larger Florida subtropical seascape. Currents flowing through 

the Tortugas can disperse reef fishery species larvae spawned 

in the Tortugas as far as Cape Canaveral on the Atlantic coast 

and Tampa Bay on the Gulf coast.

Supplemental Activities

1) Expand ongoing efforts to model larval transport 

throughout the region.

Previous and Existing Studies. There have been several efforts to model Tortugas reef fishery species larval transport 

(Lee et al. 1994, Lee et al. 1999, Lee and Williams 1999, 

Lindeman et al. 2001, Yueng et al. 2004).

2) Implement a demonstration of connectivity between 

the RNA and surrounding regions by inducing females to 

produce larvae with a unique genetic marker, possibly by 

chemical- or radiation-induced chromosome damage or 

insertion of a particular gene sequence into lab-reared 

females. 

Previous and Existing Studies. A genetic marker to identify genetic differences between individual nurse sharks and 

perhaps nurse sharks spawned in DTNP has been developed 

(Saville et al. 2002).

Red grouper sheltering in gorgorian soft corals in the Tortugas. 

Photo by Jerry Ault, Univ. of Miami/RSMAS.
16

RNA Performance Topic 6: Incorporate 

social sciences into the research and 

monitoring program.

MOU SOW A.2.d: “Incorporate social sciences into the 

research and monitoring program for evaluating the RNA 

performance measures. The social science component shall 

include collection of compliance rates and enforcement activity in the RNA and surveys of visitor experiences related to 

the RNA.”

Performance Measures

Fishing activity, SCUBA and snorkeling activity (total number of SCUBA divers and snorkelers and duration in water 

for each designated dive site and reference site), number 

of boats anchoring by location, visitor satisfaction, and 

law enforcement activity and regulatory compliance rates 

(number and percentage of violations by user permit 

type). Creel survey performance measures and required 

fishing activity data are discussed under Topic 3. 

Essential Activities

1) Collect and analyze fishing, diving, and boat use data 

needed to assess the effects of RNA implementation on 

visitor use. 

Previous and Existing Studies. DTNP private boat recreational fishing activity (creel survey) data were collected from 

1981-1984 and 2000-2004. DTNP charter boat recreational 

fishing activity surveys using a logbook system began in 2005. 

Information from these surveys is summarized under Topic 

3. The only SCUBA diving use data that exist were obtained 

from park-permitted live-aboard vessel operators. These operators were required only to report dive locations. There are 

no recent, adequate DTNP boat use surveys.

Proposed Studies. Park visitor use data, inside and outside 

the RNA, are needed for several science activities discussed 

previously in this plan. Visitor fishing activity (creel) surveys 

are described in Topic 3. SCUBA diving and snorkeling use 

data are required to assess ecological effects at designated 

dive sites and elsewhere (Topic 4). Boat use data are needed 

to evaluate the ecological effects of boat anchoring on coral 

reefs adjacent to the RNA and of creating the RNA no anchor 

zone (Topic 4).

Recreational boat and diver use data will be collected 

through the currently proposed park permit system. All recreational diving and fishing activity in the park will require 

a permit which will include total number of SCUBA divers 

and snorkelers and duration in water by location. All permitted diving and fishing business operators will be required to 

submit trip information, including total number of SCUBA 

divers and snorkelers and duration in water by location. 

If the proposed permit system proves infeasible to implement, less comprehensive (and more costly) aerial surveys, 

visual surveys from Garden and Loggerhead Keys, and law 

enforcement patrol surveys of visitor use, will be necessary. 

Aerial surveys should be designed to meet as many of the use 

information needs for Topics 3 and 4 as possible. Aerial survey 

design should be similar to those conducted elsewhere (e.g., 

the current ENP marine boat surveys).

2) Implement an appraisal system to characterize visitor use 

experience and views regarding RNA implementation. 

Previous and Existing Studies. The primary information 

on public views of RNA implementation is derived from the 

public comments on the DTNP General Management Plan 

(GMP) alternatives through the NEPA process (DTNP 2002). 

The most recent study on park visitor use was in 2002 (Le and 

Littlejohn 2003). This study asked visitors about the importance of protecting natural resources; however, there were no 

specific questions about RNA implementation. 

Proposed Studies. Understanding visitor use experiences 

and perceptions regarding the RNA, and similar new stewardship regulations such as the Special Protection Zones, are 

critical to effective park adaptive management. Since the behaviors and actions of recreational users can have significant 

impact on resources, a study designed to identify attitudinal 

and cognitive factors contributing to these behaviors could 

assist park managers in developing education, outreach and 

interpretation programs, promoting compliance with regulations, and helping visitors to protect the resources they enjoy. 

NPS and FWC seek to understand attitudes and perceptions 

toward park resources and new regulations and how these 

factors affect visitor use patterns and visitor satisfaction over 

time. 

The following activities are recommended; however this 

list may need to be prioritized and scaled back to fit available 

resources.

Visitor snorkeling in Dry Tortugas National Park. Photo by Brett 

Seymour, NPS.
Assessing the Conservation Efficacy of the Dry Tortugas National Park Research Natural Area 17

Measure visitor and broader public knowledge and perceptions about the RNA and other marine ecosystem 

stewardship issues, including marine ecological resource 

conditions, coral decline, over-fishing, anchoring, and regulations designed to protect and restore coral reefs, seagrass, and fishery resources. How do these views and experiences change over time?

Evaluate visitor RNA use experience and satisfaction. How 

has RNA implementation affected visitor use throughout 

the park? How do these views and experiences change 

over time?

Obtain a general socio-demographic profile of boaters, anglers, divers, and snorkelers

Measure visitor contact with environmental education or 

interpretation programs via brochures, site bulletins, public service announcements, marine radio, visitor contact, 

and visitor centers.

Coordinate socio-economic studies and human dimension assessments with NOAA Biogeographic Assessment 

already completed or underway.

Integrate information obtained from social science surveys, visitor use patterns, and recreational fishing activity 

surveys (creel and charter boat).

3) Monitor RNA law enforcement activity and regulation 

compliance rates by visitors, commercial operators, and 

scientific researchers on an annual basis.

Previous and Existing Studies. We have no knowledge of 

studies that have monitored law enforcement activity and 

regulation compliance rates by visitors and businesses.

Supplemental Activities

1) Assess the economic effects of RNA implementation 

using standard socioeconomic methods. 

Previous and Existing Studies. NOAA has conducted 

socioeconomic research on the TER before establishment 

(Leeworthy and Wiley 2000, Leeworthy et al. 2004) and is 

currently assessing the socioeconomic effects of TER implementation (NOAA 2006).

Proposed Studies. What are the economic effects of RNA 

implementation on private businesses operating in the park? 

This activity should be integrated into a more comprehensive 

assessment of the economic effects of DTNP GMP implementation. For example, the GMP limits the number and type of 

private businesses operating in the park. Conduct an analysis 

of the economic benefits of DTNP visitation using the NPS 

Money Generation Model II. Discerning the economic effects on fishing businesses should be coordinated with similar 

NOAA efforts in the Tortugas region. 













Schedule of Deliverables

The MOU established between FWC and the NPS stipulates 

that a jointly prepared report on the evaluation of the performance of the RNA will be provided to FWC Commissioners, 

NPS managers, and the public at three and five year intervals 

as described below.

Three-year Interim Report

The three-year interim report will be completed in February 

2010 and will summarize the progress of implementation of 

the essential activities whether funded or not. It will also include an update on the supplemental activities. 

Five-year Interim Report

The five-year interim report will be completed in February 

2012 and will provide a detailed description of results of all 

the ongoing studies and discuss the results in relation to the 

stated goals of the RNA.

NPS diver evaluating benthic communities in Dry Tortugas 

National Park. Photo by Brett Seymour, NPS.
18

Literature Cited

Ault, J. S., S.G. Smith, G. A. Meester, J. Luo, J.A. Bohnsack and S. L. 

Miller. 2002. Baseline multispecies coral reef fish stock assessment for the Dry Tortugas. NOAA Technical Memorandum 

NMFS-SEFSC-487. 117 pp.

Ault, J. S., S. G. Smith and T. Schmidt. 2006. Assessment of coral reef 

fishery resources in Dry Tortugas National Park: 1999-2004. Final 

Report to National Park Service, Contract No. H5000000B494-

J5280040007. 80 p. Available at: http://bonefish.rsmas.miami.edu/

femar/Publications.htm.

Ault, J. S., S.G. Smith, J.A. Bohnsack, J. Luo, N.A. Farmer, D. E. Harper 

and D. B. McClellan. 2007. Fishery Independent Monitoring 

of Coral Reef Fishes, Coral Reefs, and Macroinvertebrates in 

the Dry Tortugas. FY 2006 Final Report, National Park Service 

Contract No. H5000000B494-J5280040007.

Bohnsack, J. A. and S. P. Bannerot. 1986. A stationary visual census 

technique for quantitatively assessing community structure of 

coral reef fishes. NOAA Technical Report NMFS 41, 15p.

Burke, J. S., C. A. Currin, D. W. Field, M. S. Fonseca, J. A. Hare, W. J. 

Kenworthy and A. V. Uhrin. 2003. Biogeographic analysis of the 

Tortugas Ecological Reserve: examining the refuge effect following reserve establishment. Marine Conservation Series MSD04-1. U. S. Department of Commerce, National Oceanic and 

Atmospheric Administration, Marine Sanctuaries Division, Silver 

Spring, MD. 28pp.

Burton, M. L., K. L. Brennan, R. C. Munoz and R. O. Parker. 2005. 

Preliminary evidence of increased spawning aggregations of mutton snapper (Lutjanus analis) at Riley’s Hump two years after 

establishment of the Tortugas South Ecological Reserve. Fishery 

Bulletin 103, no. 2: 404-10.

Collins, L. A., G. R. Fitzhugh, L. A. Lombardi-Carlson, H. M. Lyon, W. 

T. Walling and D.W. Oliver. 2002. Characterization of red grouper 

(Serranidae: Epinephelus morio) reproduction from the eastern 

Gulf of Mexico. Southeast Fisheries Science Center, National 

Marine Fisheries Service. Contribution Series 2002-07. July 26, 

2002. Panama City, FL. 

Domeier, M. L. 2004. A potential larval recruitment pathway originating from a Florida marine protected area. Fisheries Oceanography 

13, no. 5: 287-94.

DTNP. 2002. Dry Tortugas National Park Final General Management 

Plan and Environmental Impact Statement. National Park Service, 

U.S. Department of the Interior.

Dulvy, N. K., R. P. Freckleton and N. V. C. Polunin. 2004. Coral reef 

cascades and the indirect effects of predator removal by exploitation. Ecology Letters. 7(5): 410-416.

Fonseca, M. S., A. V. Uhrin, C. A. Currin, J. S. Burke, D. W. Field, C. A. 

Addison, L. L. Wood, G. A. Piniak, T. S. Viehman and C. S. Bonn. 

2006. Ongoing monitoring of the Tortugas Ecological Reserve: 

assessing the consequences of reserve design. NOAA Technical 

Memorandum NOS NCCOS 22. 48 pp.

Galal, N., R. F. G. Ormond and O. Hassan. 2002. Effect of a network 

of no-take reserves in increasing catch per unit effort and stocks 

of exploited reef fish at Nabq, South Sinai, Egypt. Marine and 

Freshwater Research 53: 199-205.

Garrison, V. H., C. S. Rogers and J. Beets. 1998. Of reef fishes, overfishing and in situ observations of fish traps in St. John, U.S. Virgin 

Islands. Revisita de Biologia Tropical 46: 41-59.

Green, R. H. 1979. Sampling design and statistical methods for environmental biologists. John Wiley and Sons, New York, New York, 

USA.

Halpern, B. S. 2003. The Impact of Marine Reserves: Do Reserves 

Work and Does Reserve Size Matter? Ecological Applications 

13(1) Supplement: S117-S137.

Harriott, V. J., D. Davis and S. A. Banks. 1997. Recreational diving and 

its impact in marine protected areas in eastern Australia. Ambio 

26: 173–179.

Hawkins, J. P. and C. M. Roberts. 1992. Effects of recreational SCUBA 

diving on fore-reef slope communities of coral reefs. Biological 

Conservation 62: 171–178.

Hawkins, J. P. and c. M. Roberts. 1997. Estimating the carrying capacity of coral reefs for scuba diving. Proc 8th Int Coral Reef Symp 

2: 1923-1926.

Hawkins, J. P., C. M. Roberts, T. van’t Hof, K. de Meyer, J. Tratalos and 

C. Aldam. 1999. Effects of recreational scuba diving on Caribbean 

coral and fish communities. Conservation Biology 13: 888–897.

Le, Y. and M. Littlejohn. 2003. Dry Tortugas National Park Visitor 

Study: Spring 2002. National Park Service, Visitor Services 

Project, Report 132. 113pp.

Lee, T. N., M. E. Clarke, E. Williams, A. F. Szmant and T. Berger. 1994. 

Evolution of the Tortugas Gyre and its influence on the recruitment in the Florida Keys. Bulletin of Marine Science 54, no. 3: 

621-46.

Lee, T. N., E. Johns, D. Wilson and E. Williams. 1999. Site characterization for the Tortugas region : physical oceanography and recruitment, University of Miami, RSMAS, Miami, FL.

Lee, T. N. and E. Williams. 1999. Mean distribution and seasonal variability of coastal currents and temperature in the Florida keys with 

implications for larval recruitment. Bulletin of Marine Science 64, 

no. 1: 35-56.

Leeworthy, V. R. and P. C. Wiley. 2000. Proposed Tortugas 2000 

Ecological Reserve, Final Socioeconomic Impact Analysis of 

Alternatives. National Oceanic and Atmospheric Administration, 

National Ocean Service, Special Projects, Silver Spring, Maryland. 

October 2000. http://marineeconomics.noaa.gov/reserves/

Tortugas.pdf.

Leeworthy, V. R., P. C. Wiley and J. D. Hospital. 2004. Importancesatisfaction ratings five-year comparison, SPA & ER use, and socioeconomic and ecological monitoring. Comparison of results 

1995-96 to 2000-01. Silver Spring, MD: Special Projects, NOS. 59 

pp.

Limouzy-Paris, C. B., H. C. Graber, D. L. Jones, A. W. Roepke and 

W. J. Richards. 1997. Translocation of larval coral reef fishes via 

sub-mesoscale spin-off eddies from the Florida current. Bulletin 

of Marine Science 60: 966-83.

Lindeman, K. C., R. Pugliese, G. T. Waugh and J. S. Ault. 2000. 

Developmental patterns within a multispecies reef fishery: management applications for essential fish habitats and protected areas. Bulletin of Marine Science 66, no. 3: 929-56.

Lindeman, K. C., T. N. Lee, W. D. Wilson, R. Claro and J. S. Ault. 

2001. Transport of larvae originating in southwest Cuba and 
Assessing the Conservation Efficacy of the Dry Tortugas National Park Research Natural Area 19

the Dry Tortugas : evidence for partial retention in grunts and 

snappers. Proceedings of the Gulf and Caribbean Fisheries 

Institute, pp. 732-747. North Fort Pierce, Florida: Harbor Branch 

Oceanographic Institute.

Lubchenco, J., S. R. Palumbi, S.D. Gaines and S. Andelman. 2003. 

Plugging a hole in the ocean: The emerging science of marine reserves. Ecological Applications 13(1) Supplement: S3-S7.

McClanahan, T. R. and S. Mangi. 2000. Spillover of exploitable 

fishes from a marine park and its effects on the adjacent fishery.

Ecological Applications 10: 1792-1805.

Mumby, P. J., C. P. Dahlgren, A. R. Harborne, C.V. Kappel, F. Micheli, 

D.R. Brumbaugh, K.E. Holmes, J.M. Mendes, K. Broad, J.N. 

Sanchirico, K. Buch, S. Box, R.W. Stoffle, and A.B. Gill. 2006. 

Fishing, trophic cascades, and the process of grazing on coral 

reefs. Science 311: 98-101.

National Academy of Sciences. 2001. Marine Protected Areas: Tools 

for Sustaining Ocean Ecosystems. National Academy Press, 

Washington, D.C.

NOAA. 2006. An Integrated Biogeographic Assessment of the 

Tortugas Ecological Reserve: Draft Work Plan. National Oceanic 

and Atmospheric Administration, National Ocean Service, Silver 

Springs , MD. 13pp.

Pauly, D., V. Christensen, J. Dalsgaard, R. Froese and F. Torres. 1998. 

Fishing down marine food webs. Science 279: 860–863.

Roberts, C. M., J. A. Bohnsack, F. Gell, J. P. Hawkins and R. Goodridge 

2001. Effects of marine reserves on adjacent fisheries. Science 

294: 1920-1923.

Rouphael, A. B. and G. J. Inglis. 2002. Increased Spatial and Temporal 

Variability in Coral Damage Caused by Recreational Scuba Diving. 

Ecological Applications 12(2): 427-440.

Russ, G. R. and A. C. Alcala. 1998. Natural fishing experiments in 

marine reserves 1983-1993: community and trophic responses. 

Coral Reefs 17: 383-397.

Russ, G. R., A. C. Alcala and A. P. Maypa. 2003. Spillover from marine 

reserves: the case of Naso vlamingii at Apo Island, the Philippines. 

Mar. Ecol. Prog. Ser. 264: 15-20.

Russ, G. R., A. C. Alcala, A. P. Maypa, H. P. Calumpong and A.T. 

White. 2004. Marine reserves benefit local fisheries. Ecological 

Applications 14(2): 597-606.

Sala, E., O. Aburto-Oropeza, M. Reza, G. Paredes, and L.G. LópezLemus. 2004. Fishing down coastal food webs in the Gulf of 

California. Fisheries 29: 19-25.

Saville, K. J., A. M. Lindley, E. G. Maries, J. C. Carrier and H. L Pratt. 

2002. Multiple paternity in the nurse shark, Ginglymostoma cirratum. Environmental Biology of Fishes: 347-51.

Schleyer, M.H. and B.J. Tomalin. 2000. Damage on South African coral 

reefs and an assessment of their sustainable diving capacity using 

a fisheries approach. Bulletin of Marine Science 67: 1025–1042.

South East Data Assessment and Review (SEDAR). 2001-2005. 

National Marine Fisheries Service (NMFS) reef fish stock assessments. 2006. These reports are available on the following NMFS 

Southeast Fisheries Science Center (SEFSC) website: (http://

www.sefsc.noaa.gov/sedar/).

Underwood, A. J. 1992. Beyond BACI: the detection of environmental 

impacts on populations in the real, but variable, world. Journal of 

Experimental Marine Biology and Ecology 161: 145–178.

Wolff, N., R. Grober-Dunsmore, C. S. Rogers and J. Beets. 1999. 

Management implications of fish trap effectiveness in adjacent 

coral reef and gorgonian habitats. Environmental Biology of 

Fishes 55: 81-90.

Yeung, C., J., D. Lamkin, D. Jones, M. Criales and W. Richards. 2004. 

Large eddy, small eddy - supplying recruits to the South Florida 

ecosystem : Giros grandes, giros pequenos - proveen reclutas al 

ecosistema del Sur de la Florida. Proceedings of the Gulf and 

Caribbean Fisheries Institute, 1048s.l.: s.n.

Zakai, D. and N. E. Chadwick-Furman. 2002. Impacts of intensive 

recreational diving of reef corals at Eilat, northern Red Sea. 

Biological Conservation 105: 179-187.
Assessing the Conservation Efficacy of the Dry Tortugas National Park Research Natural Area 21

Appendix I: Memorandum of understanding
22
Assessing the Conservation Efficacy of the Dry Tortugas National Park Research Natural Area 23
24
Assessing the Conservation Efficacy of the Dry Tortugas National Park Research Natural Area 25
26
Assessing the Conservation Efficacy of the Dry Tortugas National Park Research Natural Area 27
28
Assessing the Conservation Efficacy of the Dry Tortugas National Park Research Natural Area 29
30
Assessing the Conservation Efficacy of the Dry Tortugas National Park Research Natural Area 31

Appendix II: Public Comment and Agency Response

Dry Tortugas Research Natural Area Science Plan

Public Workshop, Key Largo, FL, May 3, 2007 

Public Comments and NPS/FWC Responses

Overview/Introduction Session Comments

Comment Response

Link science activities to fishery related impacts. The science activities presented in this plan are directly 

linked to fishery related effects.

A funding performance measure (PM) is necessary to 

complement the plan – if the funding is not available, the 

scientific studies cannot be completed.

Need a performance standard to measure how successful in getting funding, since entire science plan depends 

on funding. I.e., how much did not get done because did 

not get funded (agency folks can’t lobby for funding, but 

NGOs can and can assist).

We appreciate these comments; however, it will be difficult to come up with very specific funding performance 

measures that have direct corresponding benefits related 

to scientific information. As opposed to eliminating completely many essential activities, we intend to scale-up or 

scale-down activities based on funding. Our aim is to have 

some substantial activity for each science topic.

Use ‘funding scorecard’ as leverage as what has/has not 

got funding.

See above.

PMs need to be refocused to specify thresholds, amounts, 

or ability to estimate differences. More detailed PM description is needed to drive the data collection.

Performance measures are not targets or quantified objectives; they are measures used to assess progress toward a 

target. We will review the performance measures to ensure 

that are sufficiently described. Long term resource stewardship objectives are stated for Topic 4. The long term 

resource stewardship objective for reef fishery species is 

to restore and maintain reef gamefish species populations 

(stocks) at levels that will sustain recreational fishing in 

DTNP.

We agree that it may be valuable to develop quantitative targets for each performance measure. At this point, 

performance measure targets are directional and qualitative. The principle investigators that develop more detailed sampling designs should consider use of statistical 

analysis, such as power analysis, and other techniques to 

develop statistically sound quantitative targets. Much of 

the first few years of study will help establish baseline variability in performance measures. This information will be 

considered for development of quantitative targets. 

The need for aging structures (otoliths, etc.) was mentioned earlier. All the programs need to work together and 

collect data in an efficient design.

We have now incorporated an aging component of our 

study using otoliths into the monitoring plan.
32

Complete habitat mapping for all areas of DTNP (particularly deeper water areas). Lidar mapping approaches 

along western boundary. Passage-ways of hard bottom areas. Extract to whole population level estimates, and improve sampling design.

There is an interagency benthic habitat mapping project/

program underway that includes DTNP.

Should not be rushing to get quick science answers. We agree.

What is the science funding to support this? Work into ongoing agency funding initiatives over the next few years.Funding is expected to come from the National Park Service, the U.S. Geological Survey, and the Florida Fish and 

Wildlife Conservation Commission.

Measuring accountability of performance measures, and 

essential activities, will take substantial resources.

We agree.

How to track funding accountability when internal funding gets shifted to take on different priorities.The National Park Service and Florida Fish and Wildlife 

Conservation Commission are committed to maintaining a sustainable science program in the Research Natural 

Area.

Need to know how much this is going to cost. State demanding all this research, state should be held accountable if not fully funded, state acknowledges partnership 

by funding priorities.

The National Park Service and Florida Fish and Wildlife 

Conservation Commission are working as partners to 

maintain a sustainable science program in the Research 

Natural Area. For example, FWC and NPS scientists recently submitted a joint proposal to fund portions of Topic 

1 essential activities. The proposal has been accepted for 

funding by the USGS State Partnership Program.

Difficult to show how dollars are spent if conflated with 

other uses simultaneously (e.g., immigration, drug enforcement, fishing).

Funding received for RNA science activities will be spent 

on science. 

Need to capture other sources of money, competitive programs, (e.g., grants).We agree, and are pursuing other funding sources. For example, two of the essential activities in this plan are being 

funded through the USGS State Partnership Program.
Assessing the Conservation Efficacy of the Dry Tortugas National Park Research Natural Area 33

Performance Topic 1 Comments 

Performance Measure Comments:

Comment Response

Add frequency of occurrence for all fish observed in visual 

surveys.

This measure is included in the current visual surveys and 

has been explicitly stated in the performance measure.

Essential Activity #1 Comments:

Comment Response

Co-sampling of macro-invertebrates and benthic communities, etc. Requires greater logistical support and strong 

project coordination (use of smaller boats, on-site housing, etc.) to reduce costs/permitting requirements. Details 

on sampling size, precision and cost of detection, etc. to 

be worked out.

This activity is being done to some extent by NPS cooperator conducting reef fish surveys (or by cooperator’s associates). Fish habitat characterization is an integral part of 

the current and planned reef fish surveys. We will consider 

incorporating more extensive benthic communities monitoring. Furthermore, NPS is currently conducting multiple 

benthic communities monitoring and assessment projects; 

plus additional projects are proposed under Topic 4 of this 

plan. NPS and FWC plan to hold a research coordination 

meeting in winter of 2008 and regularly thereafter. 

Link RNA/DRTO specific surveys to broader regional 

perspective, with comparisons to biannual Keys-wide survey. Must conduct annual RNA-specific surveys to provide adequate information for 3-5 year reviews.

DRTO studies are currently linked to, and part of, the 

current biannual Tortugas wide survey, and DRTO reef 

fisheries assessments are compared to the Keys-wide reef 

fisheries assessments. These are conducted by the same 

scientists. We agree that there needs to be more linkage 

and comparison between the RNA and FKNMS SPAs, 

particularly regarding the conservation efficacy of no fishing marine reserves.

Annual RNA-specific surveys are part of the plan.

Develop more qualitative measures to show early benefits 

of RNA closure (more and larger observed fish).

The measures suggested, abundance (“more fish”) and 

size (“larger fish”), are integral components of the existing and planned surveys. Qualitative measures are more 

coarse and thus perhaps less likely to show early benefits. 

Essential Activity #2 Comments:

Comment Response

Develop a table/matrix of how this activity (collection of 

fishery information using traps and hook-and-line) links 

with multiple RNA science topics

Great suggestion. We will consider this.
34

For fish traps...include RNA, natural/cultural, historic use 

zones (all in southern half of DRTO initially). Focus on 

exploited species first, since this provides more detailed 

information.

This activity is proposed to be conducted in the RNA no 

fishing zone and fishing areas adjacent to the RNA. This 

activity does focus on gamefish (“exploited”) species; we 

concur with this comment.

Supplemental Activity #1 Comments:

Comment Response

Link fish movement studies with visual census surveys, 

particularly for juvenile fish. Link visual surveys with recruitment.

We will attempt to provide these linkages.

Proposal to use fish nets to sample juvenile fish, by working up against inshore/beaches.If additional resources become available, we will consider 

adding these sampling efforts.

Monthly fish counts by on-site resource management 

staff.

This is not practical because resource management staffs 

are limited. Furthermore, the marine fisheries scientists conducting the current surveys have suggested that 

monthly sampling is not necessary.

Incorporate the Reef Environmental Education Foundation (REEF) roving volunteer diver surveys, adding cryptic fish species to taxonomic inventory (abundance/occurrence scores). Investigate incorporation of quantitative 

Reef Visual Census (RVC) methodology to add precision. 

Involves public/constituents into DTNP science program.

We have considered the incorporation of REEF surveys 

into this plan. We are awaiting input from REEF and will 

incorporate it in future versions of the plan.

Use of fish monitoring cameras? This methodology will be considered and evaluated. 

Supplemental Activity #2 Comments:

Comment Response

R&D project to examine seasonal components of RVC 

sampling (one-time twice a year, summer-winter survey). 

We will consider including this activity. However, there 

likely will be funding and logistical limitations. Such seasonal studies done elsewhere in the Keys suggest that seasonal sampling is no more effective than once a year sampling.
Assessing the Conservation Efficacy of the Dry Tortugas National Park Research Natural Area 35

Performance Topic 2 Comments

Performance Measure Comments:

Comment Response

Natural mortality rates should be quantified as an essential activity and key parameter for all assessments, tagging 

data are key for obtaining these data.

This recommendation will be considered.

General concern that science plan priorities are DTNPcentric and RNA-centric. Flux from the RNA is critical, 

other areas (TER) are secondary.

Topic 2 science activities do include areas outside DTNP. 

However, the purpose of the FWC-NPS MOU, and thus 

the science plan, is to assess the conservation efficacy of 

the RNA.

Essential Activity #1 Comments:

Comment Response

Item 1 is possibly supplemental, only external tags are 

necessary.

We believe that sonic tagging and tracking is a more effective measure of net emigration from the RNA. Both methods are valuable.

Disagrees, recommends that the sonic array is essential, 

less reliance on recreational reports, higher level of scientific rigor – the two methods are complementary.

We agree.

We have been using sonic tagging for several years now – a 

potential complement is to ring the RNA with receivers 

(~80), put animals inside and out, and look at flux.

“Ring the RNA with receivers” is the ideal approach. However, funding and logistical constraints will likely require 

us to focus on likely key fish movement pathways.

Recommends a two-phased tagging study – to document 

habitat specific movements, and a broader encompassing 

array for movements into/out of the RNA and TERs (spillover effects).

We will consider and evaluate including this approach.

Recommends changing emigration/immigration to “flux,” 

since understanding fish movements is the essential activity.

We will incorporate the term “flux.”

Connectivity is an important topic and may be a better description of this effort. May need to include a larger concept, beyond emigration.We agree that connectivity is an important topic. Topic 5 

also addresses connectivity (on a broader scale). We will 

include text relating appropriate science activities to the 

larger connectivity concept.
36

An acoustic study is necessary and will include external 

tagging.

We agree.

Population dynamics should not be confined to the Tortugas studies. Focus on removal of fish pressure here may 

not be necessary – data could be obtained from other areas in the region. 

We realize that fisheries management is a regional issue. 

Thus, we planned to coordinate work in this science plan 

with similar scientific studies in the Keys and other relevant areas.

Should be communication between investigators involved 

in all sonic studies.

We agree and will incorporate that topic into our 2008 research coordination meeting.

Mote Marine Lab is establishing a large acoustic study 

(Dalhousie Univ.) that we should look into, consider 

working together.

We will.

Important to look at flux in a broad fashion, including 

species that are important to the system. Okay to prioritize 

snapper-grouper complex, but others are also important. 

Consider functional groups.

We will consider and evaluate including other functional 

groups.

Why is there no performance measure for non-target species, they have great value to divers and snorkelers. Non-target (i.e., non-fishery) species are addressed in 

Topics 1 and 4.

Nurse shark reproduction occurs at DTNP, all species 

should be considered.

DTNP has created a no public access nurse shark reproduction special protection zone. We have been and will 

continue to coordinate with Wes Pratt (Mote Marine Laboratory) on nurse shark research.

Comment: from a policy perspective, FWC may not readily embrace Marine Protected Areas (MPAs). These (tagging) studies and the funding are essential. Whatever we 

need, whatever we can look at, is important.

We agree that evaluating as many possible parameters relative to this essential activity is important. We will provide 

that information to the FWC in our future reports and 

presentations.

Try to obtain larger fishes that could carry a satellite tag. 

Independent of sonic array and specific geopositioning. 

Tarpon – goliath grouper, etc. Expensive, but could be 

done on a limited basis.

We will consider including this approach.
Assessing the Conservation Efficacy of the Dry Tortugas National Park Research Natural Area 37

Essential Activity #2 Comments:

Comment Response

The most substantial value for the use of external tags is 

to promote public involvement and education (benefits of 

MPAs).

We agree that this is a substantial value.

External tagging study could be enhanced with “high reward tags” to estimate a relative reporting rate. This is a 

critical factor for analyzing data quality.

We will consider including this approach.

To determine net emigration, fish will need to be tagged 

(conventionally) outside of the RNA.

This activity is planned to be conducted inside and outside 

the RNA to determine net emigration.

Supplemental Activity #1 Comments: No Comments

Supplemental Activity #2 Comments:

Comment Response

Agrees with original classification suggesting that RNATER tagging activities are complementary.No response needed.
38

Performance Topic 3 Comments

Performance Measure Comments:

Comment Response

Critical information should include discards, species composition, lengths/weights.This information is and will continue to be collected by 

multiple federal and state Tortugas fisheries assessment 

programs, including DTNP.

By-catch (discards) is important to include in surveys. This information is and will continue to be collected by 

multiple federal and state Tortugas fisheries assessment 

programs, including DTNP.

Essential Activity #1 Comments:

Comment Response

Concentrate creel surveys at major boat ramp in Key West, 

etc.

We believe that it is more effective to concentrate DTNP 

creel surveys in the park. The current federally-funded 

MRFSS provides limited intercept contacts for private 

boaters returning from Tortugas fishing trips.

Difficulty in getting consistent intercept-point for private 

boats.

We are aware of this difficulty and are addressing it as best 

as possible in the recreational fishing survey design.

Partition out recreational fishing activity on Garden Key 

versus private boats.

We have been and will continue to do this.

Essential Activity #2 Comments:

Comment Response

Pilot survey in Florida in last two years, observers on 

board, multi-day trips directly to Tortugas, could increase 

level of sampling. 

DTNP permitted charter fishing boats are allowed to carry only a maximum of six anglers. These boats may be too 

small to include observers. It may not be cost effective to 

use observers on these small charter boats. However, we 

will consider this idea.

Concentrate on charter boats as best representative of 

recreational fishery. 

Collecting charter boat fishing data is an essential activity. 

Need consistent units of measure (e.g., 12 charter boats). We agree.
Assessing the Conservation Efficacy of the Dry Tortugas National Park Research Natural Area 39

Use of logbooks and law enforcement data collection, 

need coordination.

We do and will collect charter boat fishing data via a logbook system

Logbook data need to be validated. We agree. Compliance checks have and will continue to 

be made.

Does not get precise fishing location. Collecting fishing data using locations by zones/areas has 

been effective and is adequate for future data collection. 

We would have to lump precise location data into zones 

to perform statistical analyses. We must consider guides 

desire/need not to reveal specific sites. 

Essential Activity #3 Comments:

Comment Response

MRFSS regional program, but may not be at a sufficient 

level to detect changes in fishing activity level in Tortugas 

region.

This problem has been noted as a major inconsistency 

within MRFSS by the 2006 National Research Council 

review. It is being further reviewed by interagency study 

groups, for the “new” MRFSS data collection program.

Not enough observations from recreational fishing from 

Tortugas area based on MRFSS data.

We will consider this factor in conducting this activity. 

This problem has been noted as an inconsistency within 

MRFSS by the 2006 National Research Council review. It 

is being further reviewed by interagency study groups, for 

the “new” MRFSS data collection program.

Flexibility in MRFSS program to get regional-specific information.We agree. It is planned that the 2007 revision of MRFSS 

will address regional specificity and provide greater fishing location detail. 

Incorporate surveys into MRFSS review, and leverage that 

for data collection.

We agree. We are pursuing this.

Supplemental Activity #1 Comments:

Comment Response

How much activity is generated by private versus for-hire 

boats?

The purpose of this supplemental activity is to provide estimates of private and commercial activity in DTNP.
40

Supplemental Activity #2 Comments:

Comment Response

Fly-over (aerial survey) gives data point and need activity 

levels from creel survey.

We agree.

Aerial surveys capture edge effect, get info on other trips, 

GPS endpoint program?

We agree.

Aerial survey could partition out private/for-hire usages. It might not be easy to differentiate private and DTNP 

charter boats from the air. However, this is a goal of this 

topic.

Monitoring areas through satellite to detect levels of use, 

may be able to determine boat size, etc. (equipment to be 

placed within next year or so) – Vessel Monitoring System 

– will show population of vessels. May help with edging 

effects, fishing area shifts, activity levels, radar.

This activity could be evaluated for its usefulness through 

Gulf of Mexico/South Atlantic regional work groups of 

the “new” MRFSS program.

General Comments

Comment Response

Need to account for potential decrease in effort due to 

economics (e.g., fuel costs), i.e., may show artificial decrease in effort/low use related to other issues.

We agree. We will consider this factor in our analyses.

Competing laws between managing agencies causes 

angst.

Hopefully, greater cooperation among the various fisheries management agencies in the Tortugas region as planned 

and the planned MRFSS revision will ameliorate this situation.

Contract to fisheries scientists to detect effort levels preand post-closure.We will use the most effective methods to collect and analyze fishing activity data. We have contracted external fishery scientists to analyze DTNP recreational fishing data. 

Similarly, fishery scientists from fisheries management 

agencies and universities have collected and analyzed preand post-closure TER fishing activity data (these projects 

will continue).

Need to stratify effort related to species groups (e.g., bottom fishing).We agree. Fishing activity data by species and functional 

groups has been and will continue to be collected.

Biological collection of hard parts for stock assessments. We agree. Otoliths are being collected and analyzed by 

multiple federal and state fisheries management programs.
Assessing the Conservation Efficacy of the Dry Tortugas National Park Research Natural Area 41

Get biological data (e.g., hard parts, lengths/weights). This information is and will continue to be collected by 

multiple federal and state Tortugas fisheries assessment 

programs, including DTNP.

Also get gut content, gonads, get everything while have 

dead fish.

We will consider this option. 

Information from fishing tournaments, e.g., hook/line, 

spearfishing.

There are few fishing tournaments in the Tortugas. 

Spearfishing has not been permitted in DTNP for over 25 

years. MRFSS is a likely source for these data.
42

Performance Topic 4 Comments

Performance Measure Comments: Provided under Related Activities.

Essential Activity #1 Comments:

Comment Response

Notes it is difficult to pull out signal of diver damage, etc. We agree.

Notes Steve Miller’s work in the area. Notes merit to adding a stratum, but the diver impacts are not presently being 

examined.

We are aware of Steven Miller’s work. We will consider 

Miller’s and other existing projects/work in developing 

and implementing the most effective approach.

Notes no signal from Keys monitoring. We are aware of this; and that diving pressure is much less 

in DTNP than the main Keys. This why we propose an initially focused assessment on the three or four sites likely to 

receive the most diving pressure.

Heavily targeted toward physical damage. This is because three of the four activities deal with diver 

and anchor effects which are primarily physical damage.

Essential Activity #2 Comments:

Comment Response

Boat damage not limited to anchoring. We agree. RNA implementation will not prevent, or directly reduce, vessel groundings and propeller scarring.

Enforcement needs to be incorporated in evaluation. 

Work will assume perfect compliance.

We agree that enforcement is an important factor. This is 

why monitoring RNA law enforcement activity and regulation compliance rates is an essential plan activity under 

Topic 6.

Essential Activity #3 Comments: No Comments
Assessing the Conservation Efficacy of the Dry Tortugas National Park Research Natural Area 43

Supplemental Activity #1 Comments:

Comment Response

Size abundance of stony coral changes inside/out RNA. 

Would like to see more extensive randomized stratified 

information.

Since the draft report was produced and after this workshop, the NPS South Florida/ Caribbean Monitoring Network has initiated such a stratified random sampling approach. We will include this approach into the plan.
44

Performance Topic 5 Comments

Performance Measure Comments: No Comments

Essential Activity #1 Comments:

Comment Response

Representative subset versus all species to develop a 

baseline for the RNA (small numbers of samples during 

spawning season). Develop size/fecundity relationship.

We agree. Fecundity is a performance measure; we plan to 

develop size-fecundity relationships.

Analyze stomach contents of sampled fish. In addition to evaluating reproductive potential, when 

analyzing fish, gut content data may be useful. If adequate 

funding is available, this could be added to the sampling 

protocols.

Essential Activity #2 Comments:

Comment Response

Comprehensive sonic array (multiple projects) to show 

large-scale connectivity. Identify corridors between foraging and spawning areas. Flexible arrays that are adaptive 

to what we learn from tagging studies.

We are actively exploring this work with NOAA.

Essential Activity #3 Comments:

Comment Response

First identify spawning aggregation sites (from tagging 

studies). Linkages with other ongoing larval studies to collect drift vials. 

We agree and will employ this approach.

Socioeconomic benefits of larger fecund fish generated by 

the RNA. Observations of more large fish.

We agree.

Add coral mass spawning events to determine if RNA is a 

protected source.

We agree. This is a very good idea because it also addresses 

the other top priority DTNP natural resource stewardship 

issue; coral decline and lack of recovery. We will add this 

activity, probably under Topic 4.
Assessing the Conservation Efficacy of the Dry Tortugas National Park Research Natural Area 45

Essential Activity #4 Comments: No Comments

Supplemental Activity #1 Comments:

Comment Response

Seeding studies to understand local and long-distance 

transport modeling (regional scale modeling).

Some of this work has been done by NOAA. We will consider and evaluate including this activity.

Supplemental Activity #2 Comments:

Comment Response

Determine if there is a natural DTNP genetic marker? 

Microchemistry, real-world larval demonstration of connectivity.

We will consider and evaluate including this approach.
46

Performance Topic 6 Comments

Performance Measure Comments: No Comments

Essential Activity #1 Comments:

Comment Response

Permit system does not capture activities outside RNA. Our proposed permit system does include activities outside the RNA.

Essential Activity #2 Comments:

Comment Response

Use importance satisfaction models, measure perception 

by experience.

We agree and will consider this in our study design.

Need to survey general public in addition to park user 

groups.

Many members are non-users, supports surveying general 

public.

Collect information from general public, general stakeholders, residents of Florida (from those that do not necessarily use the area) – public involvement, NPS Planning, 

Environment and Public Comment (PEPC) program, 

opinion polls.

We agree. This activity recommends surveying the general 

public, in addition to park user groups. However, if funding is limited the focus will be on park visitors and user 

groups.

User experience surveys coupled with education, which 

first educate then survey, or survey then educate, or do simultaneously.

We agree.

NOAA survey will start January 2008 for broader Keys/ 

Tortugas, capture park users but won’t be able to tease out 

park or RNA, would have to up sample size to obtain that, 

don’t have complete flexibility for approval. Will need to 

modify current questionnaires to make Tortugas specific.

We will work with NOAA to expand and modify survey 

so better able to provide park- and RNA-specific information.
Assessing the Conservation Efficacy of the Dry Tortugas National Park Research Natural Area 47

Essential Activity #3 Comments:

Comment Response

Science plan greatly dependent on funding for law enforcement.We agree.

Assumes enforcement to be in place for other topic areas 

as well.

NPS will implement law enforcement support to the extent practicable.

“Waterways” (cable show focuses on keys) re-format for 

direct outreach, safe harbor issues, educate on RNA, local 

fishing shows, tweak for different markets, etc., evaluate 

opportunities.

Using the Waterways show and local fishing shows for 

RNA outreach is a very good idea. In fact, the RNA has 

already been a focal topic of the Waterways show. We will 

further pursue this with NPS Interpretation (education 

and outreach division).

Supplemental Activity #1 Comments:

Comment Response

Focus effort (research/funding) on users who could potentially be impacted negatively, but include others that 

may not be directly effected, may see economic values are 

greater for non-consumptive users than impacted fishermen, etc.

We agree with the need for an objective, comprehensive 

economic assessment of RNA implementation covering 

all user groups.
North

DRY TORTUGAS 

NATIONAL PARK

RESEARCH

NATURAL

AREA

FLORIDA KEYS NATIONAL 

MARINE SANCTUARY

TORTUGAS ECOLOGICAL RESERVE

TORTUGAS NORTH

Naples 

Miami

Key West

Area of Detail

TORTUGAS ECOLOGICAL RESERVE

TORTUGAS SOUTH
South Florida Natural Resources Center

Everglades and Dry Tortugas National Park

950 N. Krome Ave, 3rd Floor 

Homestead, FL 33030-4443

www.nps.gov/ever/naturescience/sfnrc.htm

www.MyFWC.com