FINAL WHITE ABALONE RECOVERY PLAN 

(Haliotis sorenseni) 

Prepared by 

The White Abalone Recovery Team 

for 

National Oceanic and Atmospheric Administration 

National Marine Fisheries Service 

Office of Protected Resources 

October 2008

RECOVERY PLAN 

FOR 

WHITE ABALONE (Haliotis sovenseni) 

Prepared by 

National Marine Fisheries Service 

Southwest Regional Office 

~ationalwarine Fisheries Service 

National Oceanic and Atmospheric Administration 

White Abalone Recovery Plan 

 DISCLAIMER

i

DISCLAIMER 

Recovery plans delineate reasonable actions which are believed to be required to recover and/or 

protect listed species. Plans are published by the National Marine Fisheries Service (NMFS), 

sometimes prepared with the assistance of recovery teams, contractors, state agencies, and 

others. Objectives will be obtained and any necessary funds made available subject to budgetary 

and other constraints affecting the parties involved, as well as the need to address other priorities. 

Recovery plans do not necessarily represent the views or the official positions or approval of any 

individuals or agencies involved in the plan formulation, other than NMFS. They represent the 

official position of NMFS only after they have been signed by the Assistant Administrator. 

Approved recovery plans are subject to modification as dictated by new findings, changes in 

species status and the completion of recovery actions. 

LITERATURE CITATION SHOULD READ AS FOLLOWS: 

National Marine Fisheries Service. 2008. White Abalone Recovery Plan (Haliotis sorenseni). 

National Marine Fisheries Service, Long Beach, CA. 

ADDITIONAL COPIES MAY BE OBTAINED FROM: 

United States Department of Commerce, National Oceanic 

and Atmospheric Administration, National Marine Fisheries Service, 

Southwest Regional Office 

501 W. Ocean Blvd., Suite 4200 

Long Beach, CA 90802-4213 

On Line: http://swr.nmfs.noaa.gov/

Recovery plans can be downloaded from the National Marine Fisheries Service website: 

http://www.nmfs.noaa.gov/pr/recovery/plans.htm 

Cover photograph of a white abalone by John Butler of the NOAA Southwest Fisheries Science 

Center. 

White Abalone Recovery Plan 

 TABLE OF CONTENTS

ii

TABLE OF CONTENTS 

DISCLAIMER................................................................................................................................I

TABLE OF CONTENTS ............................................................................................................II

ACKNOWLEDGMENTS ..........................................................................................................IV

EXECUTIVE SUMMARY ......................................................................................................... V

LIST OF ACRONYMS AND ABBREVIATIONS ...............................................................XIII

I. BACKGROUND..................................................................................................................... I-1

A. STATUS OF THE SPECIES.........................................................................................................I-1 

B. SPECIES’ DESCRIPTION AND TAXONOMY ...............................................................................I-1 

C. POPULATION TRENDS AND DISTRIBUTION..............................................................................I-3 

HISTORIC AND CURRENT RANGE ..................................................................................................................I-3

EXPLOITATION HISTORY...............................................................................................................................I-4

POPULATION TRENDS....................................................................................................................................I-4

D. LIFE HISTORY/ECOLOGY .....................................................................................................I-10 

REPRODUCTION...........................................................................................................................................I-10

LARVAL STAGE, SETTLEMENT, AND METAMORPHOSIS...............................................................................I-11

JUVENILE STAGE.........................................................................................................................................I-12

ADULT STAGE.............................................................................................................................................I-13

E. HABITAT CHARACTERISTICS ................................................................................................I-14 

DISTRIBUTION.............................................................................................................................................I-14

ABUNDANCE AND QUALITY OF SUITABLE HABITAT ...................................................................................I-15

F. CRITICAL HABITAT...............................................................................................................I-16 

G. REASONS FOR LISTING/CURRENT THREATS .........................................................................I-16 

LISTING FACTORS AND CURRENT THREATS................................................................................................I-16

CURRENT THREATS.....................................................................................................................................I-21

H. CONSERVATION MEASURES.................................................................................................I-25 

PRIVATE-PUBLIC PARTNERSHIPS.................................................................................................................I-25

NATIONAL MARINE FISHERIES SERVICE CONSERVATION MEASURES FOR WHITE ABALONE......................I-25

NATIONAL PARK SERVICE CONSERVATION MEASURES FOR WHITE ABALONE...........................................I-25

NATIONAL MARINE SANCTUARY CONSERVATION MEASURES FOR WHITE ABALONE ................................I-26

STATE OF CALIFORNIA CONSERVATION MEASURES FOR WHITE ABALONE ................................................I-26

MEXICAN CONSERVATION MEASURES FOR WHITE ABALONE ....................................................................I-26

I. KNOWN BIOLOGICAL CONSTRAINTS/NEEDS..........................................................................I-27 

II. RECOVERY STRATEGY .................................................................................................II-1

A. KEY FACTS AND ASSUMPTIONS ........................................................................................... II-1 

B. PRIMARY FOCUS AND JUSTIFICATION OF RECOVERY EFFORTS ............................................ II-1 

III. RECOVERY GOALS, OBJECTIVES, AND CRITERIA........................................... III-1

A. RECOVERY GOAL................................................................................................................III-1 

B. RECOVERY OBJECTIVES ......................................................................................................III-1 

C. RECOVERY CRITERIA ..........................................................................................................III-2 

IV. RECOVERY PROGRAM ................................................................................................IV-1

A. STEP-DOWN OUTLINE .........................................................................................................IV-1 

B. NARRATIVE.........................................................................................................................IV-4 
White Abalone Recovery Plan 

 TABLE OF CONTENTS

iii

RECOVERY ACTION 1. ASSESS AND MONITOR SUBPOPULATIONS IN THE WILD IN COOPERATION WITH THE 

STATE OF CALIFORNIA, OTHER FEDERAL AGENCIES, PRIVATE ORGANIZATIONS AND THE MEXICAN 

GOVERNMENT. ...........................................................................................................................................IV-4

RECOVERY ACTION 2. IDENTIFY AND CHARACTERIZE EXISTING AND POTENTIAL WHITE ABALONE 

HABITAT THROUGH ACOUSTIC REMOTE SENSING TECHNOLOGY. ................................................................IV-9

RECOVERY ACTION 3. PROTECT WHITE ABALONE POPULATIONS AND THEIR HABITAT......................IV-10

RECOVERY ACTION 4. CONTINUE, REFINE AND EXPAND CAPTIVE PROPAGATION AND ENHANCEMENT 

PROGRAM FOR WHITE ABALONE IN CALIFORNIA WITH THE GOAL OF ARTIFICIALLY ENHANCING POPULATIONS 

IN THE WILD. ............................................................................................................................................IV-13

RECOVERY ACTION 5. PLAN AND IMPLEMENT A PUBLIC OUTREACH AND EDUCATION PLAN. ............IV-16

RECOVERY ACTION 6. SECURE FINANCIAL SUPPORT FOR WHITE ABALONE RECOVERY. ....................IV-16

V. IMPLEMENTATION SCHEDULE .................................................................................. V-1

VI. LITERATURE CITED.....................................................................................................VI-1

APPENDIX A............................................................................................................................ A-1

WHITE ABALONE BROODSTOCK COLLECTION AND HOLDING PROTOCOL ................................ A-1 

APPENDIX B. ........................................................................................................................... B-1

NATIONAL MARINE FISHERIES SERVICE WHITE ABALONE GENETICS MANAGEMENT PLAN.... B-1 

APPENDIX C............................................................................................................................ C-1

NATIONAL MARINE FISHERIES SERVICE WHITE ABALONE DISEASE AND PARASITE 

MANAGEMENT PLAN ................................................................................................................ C-1 

APPENDIX D............................................................................................................................ D-1

NATIONAL MARINE FISHERIES SERVICE WHITE ABALONE PLAN FOR DISPOSITION OF EXCESS 

INDIVIDUALS ............................................................................................................................ D-1 

APPENDIX E. ........................................................................................................................... E-1

NATIONAL MARINE FISHERIES SERVICE WHITE ABALONE FIELD PLANTING PLAN...................E-1 
White Abalone Recovery Plan 

 ACKNOWLEDGMENTS

iv

ACKNOWLEDGMENTS 

NMFS gratefully acknowledges the commitment and efforts of the following Recovery Team 

members and thanks them for generously contributing their time and expertise to the 

development of the White Abalone Recovery Plan. 

Ronald Burton 

Marine Biology Research 

Division 

Scripps Institution of 

Oceanography 

University of California, San 

Diego 

John Butler 

National Oceanic and 

Atmospheric Administration 

NMFS 

Southwest Fisheries Science 

Center 

Carolyn Friedman 

School of Aquatic and Fishery 

Sciences 

University of Washington 

Leah Gerber 

Ecology, Evolution and 

Environmental Science, 

School of Life Sciences 

Arizona State University 

Peter Haaker (retired) 

California Department of Fish 

and Game 

David Kushner 

Channel Islands National Park 

David Leighton 

Carlsbad Aquaculture and 

Research Institute, Inc. 

Tom McCormick 

Channel Islands Marine 

Resource Institute 

Melissa Neuman 

National Oceanic and 

Atmospheric Administration 

NMFS 

Southwest Regional Office 

Laura Rogers-Bennett 

California Department of Fish 

and Game 

University of California 

Bodega Bay Marine 

Laboratory

 

Additional thanks go to other contributors and technical reviewers of the White Abalone 

Recovery Plan: Loo Botsford, Department of Wildlife, Fish, and Conservation Biology, 

University of California Davis, USA; Kristin Gruenthal, Scripps Institution of Oceanography, 

University of California, San Diego, USA; Alistair Hobday, Commonwealth Scientific and 

Industrial Research Organization (CSIRO) Marine Research, Hobart, Tasmania, Australia; 

Scoresby Shepherd, South Australian Research and Development Institute, Henley Beach, South 

Australia, Australia; Glenn VanBlaricom, School of Aquatic and Fishery Sciences, University of 

Washington, Seattle, Washington, USA; and NMFS staff: Cathy E. Campbell, NOAA, NMFS, 

Protected Resources Division, Southwest Regional Office, Long Beach, California, USA; David 

O’Brien, NOAA, NMFS, Protected Resources Division, Silver Spring, Maryland, USA; and 

Susan Pultz, NOAA, NMFS, Protected Resources Division, Silver Spring, Maryland, USA.

White Abalone Recovery Plan 

 EXECUTIVE SUMMARY

v

EXECUTIVE SUMMARY 

CURRENT SPECIES STATUS

White abalone (Haliotis sorenseni) was listed as an endangered species throughout its range, 

from Point Conception, California, USA to Punta Abreojos, Baja California, Mexico, under the 

Endangered Species Act (ESA) effective June, 2001 (NOAA 2001; 66 FR 29054, May 29, 

2001). The listing came after completing a comprehensive status review of the species (Hobday 

and Tegner 2000). The status review identified an urgent need for human intervention in the 

recovery of white abalone because sub-threshold densities of the animals in nature, resulting in 

repeated recruitment failure, make it unlikely that the species will recover on its own. Without 

intervention, it was estimated that the approximately 1,600 remaining white abalone in the wild 

would disappear by 2010. Surveys conducted in Southern California since the time of the status 

review confirm the status review’s conclusion that at least a 99% reduction in white abalone 

density has occurred between the 1970s and today. The National Marine Fisheries Service 

(NMFS) serves as the steward for the recovery and conservation of white abalone. White 

abalone is the first marine invertebrate to be listed under the ESA and the recovery of this highly 

fecund, long-lived species with a complex life history (pelagic larval stage and benthic adult 

stage) may be particularly challenging. Regulatory measures taken by the state of California 

during the past 30 years, including the closure of the white abalone fishery in 1996, and the 

closure of all abalone fisheries in central and southern California in 1997, have proven 

inadequate for the recovery of white abalone in the USA. White abalone abundance was driven 

to such low levels during the height of the commercial fishery that adults do not occur in high 

enough densities to successfully reproduce, contributing to repeated recruitment failure and an 

effective population size near zero. The white abalone population in Mexico is thought to be 

depleted based on commercial fishery data, but the status of the species in Mexico remains 

largely unknown. 

 

HABITAT REQUIREMENTS AND LIMITING FACTORS

White abalone are currently reported to be most abundant between 30-60 m (#100-200 ft depth), 

making them the deepest occurring abalone species in California. Historically, they occurred 

along the mainland coast, and at offshore islands and banks at depths as shallow as 5 m. Fishery 

dependent data collected in California from 1955-1993 by the California Department of Fish and 

Game (CDFG) suggest the highest percentage of total landings occurred at San Clemente Island 

and Tanner and Cortes Banks. White abalone are found in open low and high relief rock or 

boulder habitat that is interspersed with sand channels. Sand channels may be important for the 

movement and concentration of drift macroalgae, such as Laminaria farlowii, Agarum 

fimbriatum, and a variety of red algae, upon which white abalone are known to feed. 

White abalone abundance has declined significantly throughout its range as a result of 

overutilization for commercial and recreational purposes during the 1970s. Due to their life 

history characteristics as long-lived, slow moving bottom dwellers with external fertilization and 

variable recruitment rates, abalone are particularly susceptible to the pressures imposed by 

intense commercial and recreational fishing. Overfishing reduced white abalone densities to 
White Abalone Recovery Plan 

 EXECUTIVE SUMMARY

vi

such low levels that males and females were too far apart from one another to successfully 

reproduce. It is evident to the Recovery Team members and abalone experts world-wide that the 

most significant threat to white abalone is related to the long-term effects that overfishing has 

had on the species. Population densities have declined to such low levels that the probability that 

successful fertilization and subsequent recruitment events in the future can restore the species 

throughout its range has become increasingly small. 

Related to the fact that white abalone experienced significant declines in abundance throughout 

its range as a result of overutilization, is that fishing regulations for white abalone during the 

major period of its decline in the 1970s were clearly inadequate to conserve the species and 

maintain fishing at sustainable levels. Other measures taken during the late 1970s and 1980s to 

regulate the abalone fishery such as prohibiting fishing during a portion of the spawning season, 

bag limits for recreational fishermen, limited entry, and permit fees also proved ineffective. In 

1996, the California Fish and Game Commission closed the California white abalone fishery to 

protect the surviving adults. 

Loss or modification of habitat is not likely to have been a factor in the decline of white abalone. 

Estimates of natural or anthropogenic white abalone habitat losses are unknown. However, due 

to the isolation of the offshore islands of southern California and northern Baja California and 

the depth range of the species, anthropogenic impacts to white abalone habitat should be limited 

near the islands; however, the mainland habitat may have been affected to an ‘‘unknown extent’’ 

for a variety of unspecified land-based human activities. Indirect and direct effects of long-term 

climate change on white abalone habitat parameters are unknown. Estimates of available white 

abalone habitat are currently being revised. The results of ongoing habitat and abundance 

surveys may provide justification for the protection of specific habitats in the future. A better 

understanding of factors that affect larval dispersal distances and recruitment dynamics may also 

help in the construction of a sound conservation plan for the ecosystems upon which white 

abalone depend. The best available information to date suggests that factors such as disease or 

predation may have contributed to the decline of white abalone, but are not currently a major 

factor affecting the species’ continued existence.

RECOVERY STRATEGY

The primary goal of this recovery plan is to ensure the recovery of the white abalone population 

throughout its range, defined as the establishment of self-sustaining populations (those that have 

met the delisting criteria outlined below). In order to achieve this, the Recovery Team suggests 

that six actions be taken. It is important to note that this definition of white abalone recovery 

may not necessarily support a fishery. 

1. Assess and monitor subpopulations of white abalone in the wild in cooperation with the 

state of California, other federal agencies, private organizations and the Mexican 

government. 

2. Identify and characterize existing and potential white abalone habitat through acoustic 

remote sensing technology. 
White Abalone Recovery Plan 

 EXECUTIVE SUMMARY

vii

3. Protect white abalone populations and their habitat in the wild. 

4. Continue and expand a captive propagation and enhancement program for white abalone 

in California. 

5. Develop enforcement, public outreach and education plans. 

6. Secure financial support for white abalone recovery. 

By implementing these actions, surviving wild populations will be identified and the status and 

trends of these populations will be monitored. Surveys will quantify available white abalone 

habitat and generate better abundance estimates for the species throughout its range. Efforts to 

conserve and protect these populations through outreach/education programs and enforcement of 

Endangered Species Act (ESA) provisions will occur. A better understanding of the species’ 

habitat requirements will result from field surveys and will help inform the selection of habitats 

for future enhancement efforts. By refining current estimates of total population size in the wild, 

the optimal number of animals for broodstock collection, without compromising the genetic 

integrity of captive populations or resulting in a negative impact on the wild population, will be 

ascertained. Collection of broodstock animals for genetic analysis and captive breeding 

programs at multiple locations (e.g., the Channel Islands Marine Resource Institute, the Bodega 

Bay Marine Laboratory, and the NOAA Southwest Fisheries Science Center), each with unique 

capabilities, will proceed. Factors that mediate larval and juvenile survival (e.g., temperature, 

diet, density, disease) will be examined in the laboratory using captive-bred animals. In order to 

determine the success of field planting captive-reared larvae and juveniles as an enhancement 

strategy, short- and long-term survival rates will be measured during experimental field planting 

of white abalone larvae and juveniles. Experimental field planting will involve stocking animals 

over a range of sizes, densities, and spatial scales at both near shore and island locations. Longterm monitoring of wild and captively generated animals will help determine if captive 

propagation and subsequent field planting is an effective enhancement strategy. If so, a fullscale field planting program will ensue along with continued long-term monitoring of 

populations in the wild. Finally, recovery implementation will not proceed without funding to 

support all of the recovery actions. NMFS and its recovery partners are committed to pooling 

resources when possible, working collaboratively, and taking advantage of competitive funding 

opportunities at state, federal and private institutions in order to implement recovery. 

RECOVERY GOALS AND CRITERIA

The goal of the recovery plan is to increase white abalone abundance to viable and selfsustaining levels such that the species can be downlisted to threatened status and eventually 

removed from the Endangered Species List. 

The recovery criteria are stated below and apply to populations of white abalone in both the USA 

and Mexico (for geographic reference see Figure 8). 
White Abalone Recovery Plan 

 EXECUTIVE SUMMARY

viii

Downlisting Criteria

Demographic Criteria 

Criterion 1: Density and Abundance 

A. Density of emergent (detectable by human observation without substrate 

disturbance) animals (short term) must be greater than 2,000 per hectare for 75% 

of the geographic localities. 

B. Maintain a total of 380,000 animals (Rogers-Bennett et al. 2002; Butler et al. 

2006) in the wild, distributed among all geographic localities in the USA and 

Mexico. 

Criterion 2: Size Frequency 

A. Proportion of size of emergent animals in 75% of geographic localities includes 

at least 85% intermediate-size animals (90 to 130 mm) 

B. Proportion of size of emergent animals in 75% of geographic localities includes 

no more than 15% large animals (>130 mm) 

Criterion 3: Trend 

A. Achieve a stable or increasing estimate of geometric population growth (λ≥1) for 

>75% of the geographic localities over a ten year period. 

Criterion 4: Changes in distribution/reoccupation of historical range 

A. Reoccupation of white abalone over a spatial scale that encompasses their historic 

range such that 75% of the geographic localities in the USA and Mexico are 

reoccupied and meet the aforementioned recovery criteria. 

Threats-Based Criteria 

The threats criteria are organized according to the five ESA listing factors discussed in detail on 

pages 29-34 of this document. 

Listing Factor 1: Destruction, Modification, or Curtailment of Habitat or Range 

A. Destruction, modification, or curtailment of habitat or range was not an important 

factor in the decline of the species historically and is not believed to limit 

recovery of the population at this time. Currently, substrate destruction, 

suboptimal water temperatures, reduced food quantity and quality, and 

environmental pollutants/toxins are considered to be of relatively low severity and 

the effect of these threats on the species are relatively uncertain. In the future, 

potential risks imposed by substrate destruction may be averted through 

implementation of ESA Section 7 consultations and establishment of Marine 

Protected/Conservation Areas. The effects of long-term (or global) climate 

change on this species, either directly through water quality changes or indirectly 

through interactions with other species, including food items, is a potential threat 
White Abalone Recovery Plan 

 EXECUTIVE SUMMARY

ix

to white abalone that cannot be addressed through these regulatory measures. At 

this time, it is unclear what effect long-term climate change will have on the 

species. 

Listing Factor 2: Overutilization for Commercial, Recreational, Scientific, or Educational 

Purposes 

A. In California, fishing for white abalone remains prohibited and regulations for 

other abalone species are designed to protect white abalone. In Mexico, no 

federal permits are issued that allow fishing for white abalone. These measures 

limit further reductions in density and genetic diversity; see Table 5. 

Enforcement of existing regulations and public outreach will help to minimize 

illegal harvest. 

B. The CDFG Abalone Recovery and Management Plan (ARMP) remains in place 

and reflects updated information adequately to ensure that white abalone will be 

managed to maintain demographic numbers outlined in this plan. There are 

assurances of adequate regulatory authority and funding for the state to implement 

the plan. 

Listing Factor 3: Disease/predation 

A. Routine monitoring results indicate no evidence of withering syndrome (WS)-

infected animals in wild populations. 

B. The impact of any emerging disease has been evaluated and conclusions drawn 

that it is unlikely to significantly affect white abalone populations. 

C. A minimum of 50% of the white abalone geographic localities meeting the 

aforementioned demographic criteria, fall outside the resident range of sea otters. 

Listing Factor 4: Inadequate regulatory mechanisms 

A. An interagency (state/federal) task force is established to enforce regulations to 

protect established subpopulations and effectively alleviate illegal take of white 

abalone. 

B. Implementation of bilateral agreements with Mexico are continued and 

adequately deter illegal international trade. 

C. Future abalone harvest is monitored by the CDFG’s ARMP such that the health of 

the species is maintained and populations remain self-sustaining. 

D. Populations of white abalone in Mexico are adequately protected by regulatory 

mechanisms implemented by the Mexican authorities. 

Listing Factor 5: Other factors affecting the species’ continued existence 

A. Hybridization has been assessed and determined not to be a threat to the species. 
White Abalone Recovery Plan 

 EXECUTIVE SUMMARY

x

Long-term Monitoring Criteria 

Criterion 1: A monitoring program is in place and underway to evaluate population 

abundance and structure for a minimum of 50 years after downlisting. 

Criterion 2: A monitoring program is in place and underway to evaluate threats for a 

minimum of 50 years after downlisting/delisting. 

Criterion 3: A quantitative, long-term forecasting analysis plan is under development to 

ensure that probability of extinction in the wild is less than 10% in 100 years or 5 

generations, whichever is longer. 

Delisting Criteria 

Demographic Criteria 

 Criterion 1: Density and Abundance 

A. Density of emergent animals (short term) must be greater than 3,000 per hectare 

for 75% of the geographic localities (CDFG, 2005). 

B. Maintain a total of 500,000 animals (Rogers-Bennett et al. 2002, Butler et al. 

2006) in the wild, distributed among all geographic localities in the USA and Mexico. 

Maintenance of 500,000 animals is based on crude estimates of abundance necessary 

to sustain a 90% probability of persistence in 100 years, per IUCN guidelines. The 

model assumes a conservative estimate of λ= 0.90 (i.e., 10% decline per year). The 

threshold value of 500,000 animals should be updated when empirical estimates of λ

become available. 

Criterion 2: Size Frequency 

A. Proportion of size of emergent animals in each geographic locality includes at 

least 85% intermediate-size animals (90 to 130 mm) 

B. Proportion of size of emergent animals in each geographic locality includes no 

more than 15% large animals (>130 mm) 

Criterion 3: Trend 

A. Achieve a stable or increasing estimate of geometric population growth (λ≥1) for 

>75% of the geographic localities over a ten year period. 

Criterion 4: Changes in distribution/reoccupation of historical range 

A. Reoccupation of white abalone over a spatial scale that encompasses their historic 

range such that 75% of the geographic localities in the USA and Mexico are 

reoccupied and meet the aforementioned recovery criteria. 
White Abalone Recovery Plan 

 EXECUTIVE SUMMARY

xi

Threats-Based Criteria 

The threats-based criteria are the same as for downlisting. 

Long-term Monitoring Criteria 

Criterion 1: A monitoring program is in place and underway to evaluate population 

abundance and structure for a minimum of 50 years after delisting. 

Criterion 2: A monitoring program is in place and underway to evaluate threats for a 

minimum of 50 years after delisting. 

Criterion 3: A quantitative, long-term forecasting analysis plan has been developed to 

ensure that the probability of extinction in the wild is less than <5% within 100 years or 5 

generations, whichever is longer. 

Criterion 4: If information collected during the long-term monitoring period suggests: a) 

the decision to delist was in error, or 2) the species’ status has changed substantially, a 

status review of the species should be conducted. 

ACTIONS NEEDED

1. Assess and monitor subpopulations of white abalone in the wild in cooperation with the 

state of California, other federal agencies, private organizations and the Mexican 

government. 

2. Identify and characterize existing and potential white abalone habitat through acoustic 

remote sensing technology. 

3. Protect white abalone populations and their habitat in the wild.

4. Continue and expand a captive propagation program for white abalone in California. 

5. Plan and implement public outreach and education plans. 

6. Secure financial support for white abalone recovery. 

ESTIMATED COST OF CARRYING OUT RECOVERY ACTIONS DURING THE FIRST FIVE-YEARS

Cost Estimate (*103) 

Year Action 1 Action 2 Action 3 Action 4 Action 5 Action 6 TOTAL 

FY1 305 0 10 463 10 0 788 

FY2 450 0 10 468 10 0 938 

FY3 587 0 15 473 10 0 1085 

FY4 588 0 15 453 10 0 1066 

FY5 589 0 20 458 10 0 1077 

TOTAL 2519 0 70 2315 50 0 4954 
White Abalone Recovery Plan 

 EXECUTIVE SUMMARY

xii

ESTIMATED DATE AND COST OF RECOVERY

We are not able to project a recovery date and cost at this time because of uncertainty in our 

ability to carry out each of the recovery actions and whether they will directly lead to achieving 

the recovery criteria without time consuming adaptation. Specifically, the necessity of 

outplanting captive-reared abalone and uncertainties involved in doing so make it impossible to 

give a timeframe for recovery. However, we can predict that recovery is likely to take several 

decades and cost $20 million at a minimum (cost based on four times the first 5 years’ cost) . 

The logistical and financial requirements for carrying out the recovery actions are burdensome 

and even if these challenges are resolved in a reasonable amount of time, we can not predict 

delays caused by other challenges that may arise as we learn more about the species and the 

methods most effective for recovering them.
White Abalone Recovery Plan 

 LIST OF ACRONYMS AND ABBREVIATIONS

xiii

LIST OF ACRONYMS AND ABBREVIATIONS 

The following standard abbreviations for units of measurements and other scientific/technical 

acronyms and terms are found throughout this document. 

CDFG-California Department of Fish and Game 

CFR- Code of Federal Regulations 

CIMRI-Channel Islands Marine Resource Institute 

CPE-Catch Per Effort 

ESA-Endangered Species Act 

INP-Instituto Nacional de la Pesca 

IUCN- The International Union for the Conservation of Nature and Natural Resources 

MPA-Marine Protected Area 

NMFS-National Marine Fisheries Service 

NOAA-National Oceanic and Atmospheric Administration 

NOS-National Ocean Service 

NPS-National Park Service 

PVA-Population Viability Analysis 

ROV-Remotely Operated Vehicle 

SIO-Scripps Institution of Oceanography 

UCSB-University of California Santa Barbara 

USA-United States of America 

USGS-United States Geological Survey 

UV-Ultra-violet

White Abalone Recovery Plan 

 BACKGROUND

I-1

I. BACKGROUND 

A. STATUS OF THE SPECIES

White abalone (Haliotis sorenseni) was listed as an endangered species throughout its range, 

from Point Conception, California, USA, to Punta Abreojos, Baja California, Mexico, under the 

Endangered Species Act (ESA) effective June, 2001 (NOAA 2001; 66 FR 29054, May, 29, 

2001). White abalone is the first marine invertebrate to be listed under the ESA and the recovery 

of this highly fecund, long-lived species with a complex life history (pelagic larval stage and 

benthic adult stage) may be particularly challenging. The listing came after completing a 

comprehensive status review of the species (Hobday and Tegner 2000). The status review 

identified an urgent need for human intervention in the recovery of white abalone because subthreshold densities of the animals in nature, resulting in repeated recruitment failure, make it 

unlikely that the species will recover on its own. Without intervention, it was estimated that the 

approximately 1,600 remaining white abalone in the wild would disappear by 2010. The 

National Marine Fisheries Service (NMFS) serves as the steward for the recovery and 

conservation of white abalone. Regulatory measures taken by the state of California during the 

past 30 years, including the closure of the white abalone fishery in 1996, and the closure of all 

abalone fisheries in central and southern California in 1997, have proven inadequate for the 

recovery of white abalone in the USA. White abalone abundance was driven to such low levels 

during the height of the commercial fishery that adults do not occur in high enough densities to 

successfully reproduce, contributing to repeated recruitment failure and an effective population 

size near zero. The white abalone population in Mexico is thought to be depleted based on 

commercial fishery data, but the status of the species in Mexico remains largely unknown. 

Since the early 1990s, progress has been made on several fronts to learn more about the biology 

of white abalone in California and to develop a recovery strategy for the species. The state of 

California, federal agencies, academic institutions, non-governmental organizations and others 

have conducted or participated in efforts to determine which factors contributed to white 

abalone’s decline, determine its current status, and discuss measures that should be taken to 

recover the species. In addition, this comprehensive recovery plan was developed by the white 

abalone recovery team to: 1) address threats across the species’ entire range; 2) determine and 

prioritize the actions that should be taken to recover and conserve the species; 3) and state what 

criteria should be used to gauge when and if the species can be downlisted and eventually 

removed from the list. 

B. SPECIES’ DESCRIPTION AND TAXONOMY

Abalone are prosobranch marine gastropods, in the phylum Mollusca, that first appeared in the 

fossil record about 100 million years ago. According to Crofts (1929), abalone were first 

mentioned in the fourth century B.C. by Aristotle who said, “but in the case of the wild limpet 

(called by some the ‘sea ear”) the residuum escapes beneath the shell for the shell is perforated to 

give outlet.” Aristotle was referring to the row of rounded shell perforations overlying the 
White Abalone Recovery Plan 

 BACKGROUND

I-2

respiratory cavity. These perforations or respiratory pores provide outlet for reproductive 

products and for feces and waste water that has flowed over the gills. 

White abalone was the last member of the California Haliotids, of which there are seven (Geiger 

1999), to be formally described. Bartch (1940) gives the first formal description of this deepliving (20-60 m) abalone, recounting the shell as thin and light, oval and highly arched (Figure 

1). There are three to five open respiratory pores that are highly elevated above the shell’s 

surface. Typically, the shell’s interior is a pearly white and contains a poorly differentiated or 

absent muscle scar (Cox 1962). Adults attain a maximum shell length of approximately 25 cm. 

The epipodium is a mottled yellowish green and beige color, with foliose epipodial papillae 

edged in orange, and brown cephalic tentacles (Cox 1962, Leighton 1972). There is a possible 

subspecies of white abalone found at Guadalupe Island (Mexico), although it has not been 

formally described (Howorth 1978). 

Figure 1. White abalone, Haliotis sorenseni 

The taxonomic classification for white abalone is as follows: 

Kingdom: Animalia 

Phylum: Mollusca 

Class: Gastropoda 

Subclass: Prosobranchia 

Order: Vetigastropoda 

Superfamily: Pleurotomariacea 

Family: Haliotidae (abalone) 

Genus: Haliotis (Geiger 1999) 

Species: sorenseni 
White Abalone Recovery Plan 

 BACKGROUND

I-3

C. POPULATION TRENDS AND DISTRIBUTION

HISTORIC AND CURRENT RANGE The historic range of white abalone extended from Point 

Conception, California, USA to Punta Abreojos, Baja California, Mexico (Figure 2) (Bartsch 

1940, Cox 1960, 1962). In the northern part of the California range, white abalone were reported 

as being more common along the mainland coast. In the middle portion of the California range, 

they were noted to occur more frequently at the offshore islands (especially San Clemente and 

Santa Catalina Islands)(Cox 1962, Leighton 1972). At the southern end of the range in Baja 

California, Mexico, white abalone were reported to occur more commonly along the mainland 

coast, but were also found at a number of islands including Isla Cedros and Isla Natividad 

(Guzman del Proo 1992, Shepherd et al. 1998). It remains unknown whether this distribution 

pattern resulted because of lack of suitable habitat along the mainland coast in the middle portion 

of the range, or to overfishing in these more accessible mainland regions (Hobday and Tegner 

2000). 

Since the mid-1990s, extremely low numbers of isolated survivors have been identified along the 

mainland coast in Santa Barbara County and at some of the offshore islands and banks in the 

middle portion of the range, indicating the current range of white abalone in California may be 

similar to what it was historically. No recent information on current range is available for Baja 

California. 

Figure 2. Historic range of white abalone from Point Conception, California, USA to 

Punta Abreojos, Baja California, Mexico.
White Abalone Recovery Plan 

 BACKGROUND

I-4

EXPLOITATION HISTORY The first humans to harvest abalone in California were Native 

Americans in about 7000 BC (Croker 1931). Evidence from recovered middens on the Channel 

Islands suggest that few white abalone were taken perhaps due to the local accessibility of other 

species (e.g., intertidal black abalone). The California abalone fishery was dominated by 

Chinese and Japanese immigrants from the 1850’s until the 1940’s. Again, white abalone 

catches during this time may have been insignificant because white abalone occurred in 

relatively inaccessible (deeper) habitats and because commercial and recreational harvesting was 

most intense north of Point Conception. Exploitation of white abalone in California began in 

earnest in 1968 at a time when technological advances allowed better access to deeper water sites 

inhabited by white abalone and populations of other, more accessible species began to dwindle 

(Lundy 1997). Prior to 1970, when white abalone were added as a separate species on the CDFG 

commercial fish landing receipts, white abalone were likely reported as pink abalone in landings 

data. Despite the invocation of size limits, bag limits, permit fees, efforts to reduce fishing 

effort, and gear restrictions by the CDFG during the 1970s, white abalone catches continued to 

decline and in 1996 the CDFG closed the white abalone fishery throughout its range in 

California (Hobday and Tegner 2000). 

The exploitation history of white abalone in Mexico is similar to that reported for California until 

the 1940’s. The Mexican government closed the abalone fishery to foreign fishers at that time 

and gave exclusive fishing rights to local Mexican villages (Ramade-Villanueva et al. 1998). 

The Pacific coast of Baja California was divided into 19 cooperatives which were grouped into 

five larger management regions (Guzman del Proo 1992). Additional cooperatives have been 

added since the early 1990’s and it is currently unclear how an increase in the number of 

cooperatives may be affecting abalone populations. 

POPULATION TRENDS Estimates of the total population size of white abalone past and present 

have been difficult to calculate because most data are based on emergent (adult) individuals only. 

Cryptic (juvenile) white abalone have seldom been observed in nature, even prior to exploitation 

by the fishery. In addition to body size limitations, there is evidence from other abalone species 

that factors such as presence of predators and abundance of food may mediate cryptic behavior. 

The paucity of abundance data for cryptic animals prevents establishing links between the 

numbers of early and later life stages and thus, the reconstruction of recruitment histories for 

white abalone populations has not been possible. As a result, a poor understanding of population 

dynamics exists for white abalone. Given the limitations of fishery-independent and dependent 

data, only adult population abundance and density can be evaluated for changes through time and 

space. 

Fishery-Independent Data 

The earliest fishery-independent density estimates for California are provided by Tutschulte 

(1976). Because sample sizes in Tutschulte’s study were small, applicability of these data to 

larger-scale population patterns is uncertain. The first estimate (0.23 abalone m-2) is based on 

calculations made from only seven animals that were collected in three different quadrats (10 m2

) 

at three depths (20 m, 20 m, and 33 m) in southern California between 1969-1972. A fourth 
White Abalone Recovery Plan 

 BACKGROUND

I-5

quadrat (35 m2

), examined in 1967 in the Isthmus region of Santa Catalina Island yielded a 

density of 0.0857 abalone m-2. Tutschulte (1976) purports that the historical density of white 

abalone is 1 m-2, but this estimate has limited empirical support. 

Only two fishery-independent surveys have been conducted in Mexico, both along the west coast 

and islands of Baja California. The first survey, 1968-1970, encompassed the whole coast while 

the second survey, 1977-1978, covered a much smaller area along the coast encompassing Punta 

Abreojos (Figure 8). Densities reported in 1968-1970 ranged between 0.07-0.149 m-2 and were 

similar to those reported by Tutschulte (1976) in California during a similar time period. No 

white abalone were found in 1977-1978 (Guzman del Proo 1992). 

The National Park Service (NPS) with the help of the CDFG, conducted diving and submersible 

surveys in the Channels Islands from 1980-81 and from 1992-1993, at depths ranging from 24-

37 m. Emergent white abalone density decreased by one order of magnitude from 2.1*10-3 m

-2

in the early 1980s to 1.7* 10-4 m

-2 in the early 1990s (Davis et al. 1996). The animals collected 

in 1980-81 (n=21) were not measured, but the three animals collected in 1992-93 were ≥ 137 

mm. Empty shells were also sampled during the 1992-93 survey. Of the 119 white abalone 

shells identified, only one of them was < 50 mm. This led the authors to conclude that most of 

the white abalone shells and live individuals observed in the early 1990s were remnants of the 

last major recruitment event in California thought to have occurred in the 1970s (Davis et al. 

1996). Although other invertebrate monitoring programs were conducted at the Channel Islands 

from 1966-1994, these surveys were largely conducted outside of known white abalone habitat 

(Burge et al. 1975). The presence of white abalone was rarely recorded and density estimates 

could not be calculated from these data (Hobday and Tegner 2000). 

A consortium of institutions (NPS, CDFG, University of California Santa Barbara (UCSB), 

Scripps Institution of Oceanography (SIO), the United States Geological Survey (USGS), and 

NMFS) took part in submersible surveys during 1996-1997 and 1999 in the Channel Islands 

(Anacapa, Santa Barbara, Santa Cruz, Santa Catalina, San Clemente) and Osborn, Farnsworth, 

Tanner and Cortes Banks at depths ranging from 30-70 m (Davis et al. 1998, Hobday et al. 2001, 

Lafferty et al. 2004). Emergent white abalone densities were estimated at 1.2*10-4

 m

-2 in 1996-

1997 and 2.7*10-4

 m

-2 in 1999. These densities are four orders of magnitude lower than those 

reported in 1972 by Tutschulte (1976)and represent a greater than 99% reduction in density. 

Nine animals, all > 150 mm, were observed in 1996 and 1997. In 1999, the mean length of 

measurable white abalone was 14.8 cm (SD = 2.63, N = 86). Mean length varied moderately, 

but significantly among the three sites with sufficient sample sizes to warrant comparison (Table 

1). 
White Abalone Recovery Plan 

 BACKGROUND

I-6

Table 1. Abundance and size data for white abalone collected during submersible surveys in 

1999 at the Channel Islands and offshore banks of southern California, USA (Behrens and 

Lafferty 2005). 

Location Size Range (cm) Mean Size (cm) SD (cm) N 

Tanner Bank 8.9-19.3 14.1 2.3 39 

Cortes Bank 12.0-20.7 15.7 2.8 19 

San Clemente Island 10.6-19.6 15.6 2.9 15 

Smaller animals were recorded at Tanner Bank compared to Cortes Bank and San Clemente 

Island (F2, 70 = 3.29, P = 0.04, ANOVA; Kevin Lafferty, pers. comm.). The 1999 submersible 

survey also demonstrated that most of the identified animals were solitary (80%). No juveniles 

were observed, and no groups of more than 4 animals were observed. Although it is not possible 

to analyze temporal changes in the size structure of emergent white abalone due to lack of 

multiple, consecutive year data, it is clear that primarily large animals (> 140 mm) have been 

detected in recent surveys. The most recent surveys conducted in 2002 and 2003 off the coast of 

southern California revealed a similar size composition (91-190mm; Butler et al. 2006)as that 

reported by Behrens and Lafferty (2005). 

 

Emergent white abalone population size, both prior to and post-exploitation, was determined by 

calculating a crude estimate of the total area of white abalone habitat from Pt. Conception, 

California to Punta Eugenia, Baja California, Mexico (3% of the ocean bottom between 25-65 m 

depth; (3% of the ocean bottom between 25-65m depth; Davis et al. 1998). Experts have pointed 

out problems with this estimate of available white abalone habitat, especially given the patchy 

distribution of white abalone and the limited coverage of survey areas upon which the 

extrapolation was based (Butler and Hunter 2002). Nonetheless, if it is assumed that 

approximately 966 ha of potential white abalone habitat exists throughout the species’ former 

range and that this number has remained constant since the 1970s, Hobday and Tegner (2000) 

reported a pre-exploitation population size of between 700,000-4.2 million, depending on the 

source of the data. A more recent attempt to establish baseline abundances for white abalone in 

California assumed a habitat estimate of 752 ha in California and a pre-exploitation population 

size of 360,476 (Rogers-Bennett et al. 2002). Hobday et al. (2001) report that the current white 

abalone population size is 2,540 individuals, higher than the estimate (1,600) reported during the 

Hobday and Tegner (2000) status review. 

In 2002 and 2003, remotely operated vehicle (ROV) and multi-beam sonar surveys on two banks 

off of the southern California coast revealed that the white abalone population on the banks may 

be larger than estimated by Hobday et al. (2001) for the entire range of the species. Observed 

densities and revised estimates of available white abalone habitat for the two banks were used to 

estimate the total population sizes for both banks (Tables 2, 3). The estimated total abundance is 

12,818 for Tanner Bank and 7,365 for Cortes Bank (Butler et al. 2006). The sizes of animals on 

the two banks range from approximately 9-19 cm (Figure 3; Butler et al. 2006) and 94% of the 

animals were classified as singletons (> 2m from a conspecific) (Table 4; Butler et al. 2006). 
White Abalone Recovery Plan 

 BACKGROUND

I-7

Table 2. Density estimates and standard errors, estimates of area surveyed, total white abalone 

habitat area, and population size, by depth, for Tanner Bank during ROV and multi-beam sonar 

surveys conducted in July 2002. 

Depth Density 

(No/ha) 

SE Area 

surveyed (ha) 

Habitat 

area (ha) 

Population 

30-40 6.5 2.1 3.5 245 1,592.5±514.5 

40-50 19.8 4.3 5.0 425 8,415.0±1,827.5 

50-60 4.08 1.8 2.3 689 2,811.1±1,240.2 

Total 1,619 12,818.6±3,582.2

Table 3. Density estimates and standard errors, estimates of area surveyed, total white abalone 

habitat area, and population size, by depth, for Cortes Bank during ROV and multi-beam sonar 

surveys conducted in July 2003. 

Depth Density 

(No/ha) 

SE Area 

surveyed (ha) 

Habitat 

area (ha) 

Population 

30-40 12.3 8.8 2.6 232 2,853.6±2,041.6 

40-50 6.1 2.8 1.5 423 2,580.3±1,184.4 

50-60 4.0 2.7 0.7 483 1,932.0±2,114.1 

Total 1,138 7,365.9±5,340.1 

Table 4. Number of white abalone by closest distances to another individual ranging from <1-

>50 m at all sites on Tanner and Cortes Banks (modified from Butler et al. 2006). 

Distance (m) Tanner Bank (2002) Cortes Bank (2003) Tanner Bank (2004) 

<1 25 3 2

1 1 1

2 6 1

3 4 

4 5 

5 4 

6-10 15 

11-20 33 1 4

21-30 27 2

31-40 8 

41-50 13 

> 50 57 16 33
White Abalone Recovery Plan 

 BACKGROUND

I-8

 Figure 3. Size distribution of white abalone at Tanner Bank (A) in 2002 and Cortes Bank (B) in 2003. 

 Modified from Fig. 5; Butler et al. (2006). Include N=180

Fishery-Dependent Data 

Commercial and recreational exploitation of white abalone has occurred over the last 50 years in 

California (Haaker 1994). Because white abalone was not described until 1940, it is impossible 

to estimate white abalone landings prior to this time. In 1955 white abalone was named as a 

species that could be fished and unfortunately, designated refuges put in place to protect 

populations of other abalone species, did not encompass white abalone habitat. White abalone 

catches reached a peak between 1972-1974 and declined to near zero in just five years (Figures 

4, 5). Due to this rapid and dramatic decline, the white abalone fishery was closed in March 

1996. Since that time, poaching is thought to have played a role in the continued decline of the 

species. 

The CDFG estimates that approximately 4,800 abalone per day are taken illegally in northern 

California. The relative proportions of each species contributing to the total illegal harvest in 

southern California are not known. Poaching continues to be an issue at present and will 

continue to be a problem as long as a strong monetary incentive for poaching exists ($100 per 

white abalone; Davis et al. 1998). Buyers of black market abalone include local restaurants and 

seafood markets as well as international businesses (Daniels and Floren 1998). Future 

designation of Marine Protected Areas/Conservation Areas or the closure/restriction of other 

fisheries (rockfishes) that may overlap with white abalone habitat could help to reduce illegal 

take of white abalone in California through increased enforcement and public awareness. 

Size class (cm)

Proportion of white abalone

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

9-10 10-11 11-12 12-13 13-14 14-15 15-16 16-17 17-18 18-19

Tanner Bank

Cortes Bank

A

B

Size class (cm)

Proportion of white abalone

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

9-10 10-11 11-12 12-13 13-14 14-15 15-16 16-17 17-18 18-19

0

0.05

0.1

0.15

0.2

0.25

0.3

0.35

0.4

0.45

9-10 10-11 11-12 12-13 13-14 14-15 15-16 16-17 17-18 18-19

Tanner Bank

Cortes Bank

A

B
White Abalone Recovery Plan 

 BACKGROUND

I-9

 Figure 4. California commercial catch (weight in shell) of white abalone reported in 

 CDFG bulletins for the period 1955-1997. From Hobday and Tegner (2000). 

 Figure 5. Number of white abalone () collected by recreational divers in California. The 

 number of diver days (•) is also shown as a rough measure of effort. From Hobday and 

 Tegner (2000). 

Five species of abalone, including white abalone, have been taken by the commercial fishery in 

Mexico. Recreational fishing for abalone in Mexico is prohibited and Hobday and Tegner 

(2000) hypothesized that artisanal gathering of white abalone is unlikely given the current depth 

distribution of the species. It is important to recognize that the historic and current depth 

distribution of white abalone has not been well characterized. Minimum size limits for white 

abalone have varied over time, but are currently between 110-140 mm throughout Baja 

California. White abalone collected from the USA/ Mexico border to 28 o

N made up, on 

average, between 0-28% of the total abalone catch from 1990-1998 (Hobday and Tegner 2000). 

During the 1990s white abalone catches peaked in 1996 (approximately 12,500 kg; Figure 6). 

Based on the little information available, it is likely that the white abalone population in Mexico 

has experienced decline since the 1970s and some have suggested that densities have declined to 

a level at which recruitment failure has already occurred in some areas (Hobday and Tegner 

2000). Complete and partial closures of the abalone fishery have been proposed in Mexico, but 

whether these proposals have been acted on remains uncertain. 

0

8000

16000

24000

32000

40000

48000

56000

64000

72000

1955

1957

1959

1961

1963

1965

1967

1969

1971

1973

1975

1977

1979

1981

1983

1985

1987

1989

1991

1993

1995

1997

Year

Kg (Weight In Shell)

0

5000

10000

15000

20000

25000

30000

35000

40000

1960

1962

1964

1966

1968

1970

1972

1974

1976

1978

1980

1982

1984

1986

1988

1990

1992

Year

Dive Days

0

200

400

600

800

1000

1200

1400

1600

1800

Number of White Abalone
White Abalone Recovery Plan 

 BACKGROUND

I-10

 Figure 6. Commercial catch (meat weight) of white abalone in Mexico from the USA/ 

 Mexico border to 28 o

N from 1990-1998. From Hobday and Tegner (2000). 

Illegal harvest of undersized white abalone is a problem in Mexico, but the extent of the problem 

is known only from scant data collected during three months in 1973. For example, white 

abalone made up 33.8 % of the total abalone catch in one area of Baja California during July of 

1973. Of those white abalone collected, 98.8% of them were undersized individuals. Present 

day estimates of the number of white abalone taken illegally in Baja California are not available. 

D. LIFE HISTORY/ECOLOGY

REPRODUCTION White abalone are dioecious, with separate sexes occurring in approximately a 

1:1 ratio, and exhibit broadcast spawning (i.e. directly releasing gametes into the water column 

for external fertilization). Factors known to affect fecundity in abalone include organism size 

and food availability. For those species that have been examined, fecundity has been shown to 

increase linearly with increasing body size (Tutschulte 1976, Clavier 1992). Adult abalone of 

intermediate sizes are capable of spawning over two million viable eggs, indicating high 

reproductive potential (Leighton 2000). Fecundity has been shown to decrease in several species 

of abalone (H. laevigata and in H. fulgens) when food is limited (Tegner and Dayton 1987, 

Shepherd and Breen 1992), and nutrition is essential for the production of fully viable gametes. 

Gonads of white abalone mature on an annual cycle, and the spawning season of white abalone is 

of limited duration (Leighton 2000). Synchronization of gonadal maturation and spawning are 

critical to successful fertilization. In white abalone, gonads ripen and spawning occurs in winter 

months, although sometimes spawning extends into the spring. Most of the other abalone 

species in California spawn during the late-spring through mid-autumn months. White abalone 

exhibit a high degree of spawning synchronicity relative to other California species; however, the 

environmental cues and the mechanism for synchronization are not yet known (Hobday and 

Tegner 2000, Leighton 2000). Temperature changes, lunar cycles and sea conditions have been 

associated with spawning episodes of other California abalone, but have not been unequivocally 

demonstrated as spawning cues (Ino 1952, Owen et al. 1971, Leighton 1977). The duration of an 

individual spawning event in white abalone is unknown (Hobday and Tegner 2000). In H.

0

3000

6000

9000

12000

15000

1990 1992 1994 1996 1998

Year

Kg (Meat)
White Abalone Recovery Plan 

 BACKGROUND

I-11

tuberculata, spawning events last 40-80 minutes and, in males, consist of 30-70 pulses of sperm 

release every 30-45 seconds. Males release 2- 3 x 109

 sperm cells per pulse (Clavier 1992). 

Experimental evidence suggests that fertilization rates are maximized when substantially more 

than one sperm contacts an egg, and the probability of this occurring increases significantly as 

the distance between individuals decreases (Leighton 2000). 

In addition to the duration and the degree of synchronization of spawning, the concentrations of 

gametes and the density of spawning individuals will affect the fertilization success rate and 

recruitment. Studies indicate that fertilization success in several abalone species is optimal when 

concentrations of sperm are 105 – 106 /ml (Leighton and Lewis 1982, Clavier 1992). 

Experiments conducted with sea urchins indicate, however, that even with high concentrations of 

eggs and sperm, fertilization rates will be very low (< 10%) when individuals are separated by as 

little as 1 m (Pennington 1985, Levitan 1991). Experiments conducted in the field with the 

Australian abalone, H. laevigata, indicated that fertilization rates ranged from 87.6% ±5.5% at 

the point of sperm release to 48%± 1.7%, 2 m downstream, and to 2.8%±0.7%, 16 m 

downstream (Babcock and Keesing 1999). Based on these experiments and observations in the 

field, the effective nearest-neighbor distance for successful fertilization in H. laevigata is 

estimated to be 1- 2 m (Shepherd and Browne 1993, Babcock and Keesing 1999). Although 

adults are considered relatively sedentary, aggregating behavior has been reported for a few 

abalone species (Newman 1968, Breen and Adkins 1980, VanBlaricom 1993), and several 

abalone species (e.g. H. sorenseni and H. fulgens) have been observed in a laboratory setting to 

become very active immediately prior to spawning (Leighton 2000). Aggregating and spawning 

events, however, have rarely been observed in the field, and environmental cues for aggregating 

behavior have not been identified. 

No field studies of white abalone fertilization success have been conducted. In the laboratory, 

fertilization success rates of 96-100% have been achieved (Leighton 1972). Fertilized white 

abalone eggs are about 190-200 microns in diameter and are negatively buoyant (Hobday and 

Tegner 2000). As evidenced by current information on white abalone population size structure, 

no evidence of recent recruitment exists. It is estimated that the last successful white abalone 

recruitment occurred during the 1970s (Davis et al. 1996, Hobday and Tegner 2000). 

Information is required to determine if the spatial relations of remnant populations allow 

successful spawning. 

LARVAL STAGE, SETTLEMENT, AND METAMORPHOSIS Duration of the larval stage is 

temperature dependent (Leighton 1974), but generally lasts for about 1-2 weeks. Temperature 

influences survival of larvae (Leighton, 1974 , Tutschulte, 1976). Survival of white abalone 

larvae and growth of post-larvae was greatest at 18°C, and settlement rate was greatest at 15-

16°C (Leighton 1972). Dispersal distances of abalone larvae may vary depending on the species, 

habitat characteristics and hydrodynamic conditions. Studies have shown that under either high 

or low current and wave-energy regimes, settlement occurred < 50 m away from parent abalone 

(Prince et al. 1987, McShane et al. 1988). In contrast, Shepherd et al. (1992) found no 

relationship between recruitment of H. laevigata and adult densities, and larval transport 
White Abalone Recovery Plan 

 BACKGROUND

I-12

occurred over hundreds of meters. No data on dispersal distances of white abalone larvae 

currently exist. Given that larval lifetime of white abalone larvae is relatively long (7-14 days; 

Hobday and Tegner 2000) and that larvae drift passively in water currents, the potential for 

transport does exist. 

Abalone larvae are lecithotrophic and do not actively feed while in the plankton (Leighton 2000). 

Chemical cues associated with suitable substrate have been found to induce settlement, and a 

combination of chemical, biological and physical factors are thought to be involved in triggering 

metamorphosis (Morse and Morse 1988, Leighton 2000). Recognition and acceptance of a 

suitable substrate are events critical for recruitment and survival of subsequent life stages. 

JUVENILE STAGE Generally, abalone are cryptic and photophobic in nature until they are about 

3-5 years old or when they reach a size of 75-100 mm (Cox 1962). Juveniles of this size and 

smaller occur in rock crevices, under rocks and even under the cover of adult red sea urchin 

(Strongylocentrotus franciscanus) spines (Tegner 1989). Small juveniles feed on benthic 

diatoms, bacterial films and other benthic microflora. Densities of cryptic white abalone have 

not been measured directly (Hobday and Tegner 2000). Tutschulte (1976) reported that juvenile 

white abalone <130 mm were rare in undisturbed areas in 1971, and more recent surveys by 

Davis et al. (1996) failed to detect any live juveniles. Martin Ortiz-Quintanilla observed juvenile 

white abalone in boulder habitat at depths of 5-10 m around near-shore islands between 

Ensenada and Cedros Island in Baja California, Mexico (unpublished data). Abalone larger than 

about 100 mm are classified as “emergent” abalone as they leave sheltered habitats and move to 

more open habitat to forage on attached or drifting macroalgae. Juveniles are more active than 

adults and are also more active at night based on laboratory observations (Leighton pers. 

comm.). 

In California, only four white abalone <100 mm in size have been observed since 1970. Three of 

these were observed by SCUBA divers at Yellowbanks, Santa Cruz Island, CA and one was 

observed during ROV surveys at Tanner Bank (See below). The three juveniles (32, 38 and 29 

mm; D. Kushner pers. com.) were cryptic animals that were located in artificial recruitment 

modules used by Channel Islands National Park kelp forest monitoring program. In addition, at 

Yellowbanks, three fresh white abalone shells <100 mm were also found during the same time 

that live white abalone were found. Thus, there have been so few observations of juveniles, that 

preferred juvenile habitat has yet to be accurately characterized. Even though juvenile white 

abalone are cryptic, if recruitment were occurring, one would still expect to observe shells as is 

the case with other abalone species, especially in areas where currents are not so strong that they 

would wash shell debris away. This has not been the case for white abalone. 

Information on growth rates of juveniles is limited; however, in the laboratory, growth rates were 

29.2 ±15.0 mm / year for juveniles (n=5) fed on Macrocystis (Tutschulte 1976). Growth rate is 

influenced by temperature, and different species achieve maximum growth rates at different 

temperatures. No field estimates of juvenile mortality rates have been reported for white abalone 
White Abalone Recovery Plan 

 BACKGROUND

I-13

(Hobday and Tegner 2000). The juvenile stage lasts, in general, for about 1-2 years, and ends 

upon reaching sexual maturity. 

ADULT STAGE White abalone become sexually mature when they reach sizes of approximately 

88-134 mm or ages of 4 –6 years (Tutschulte and Connell 1981). Adult white abalone reach a 

maximum size of 200-254 mm (Cox 1960), and are estimated to live for about 35-40 years 

(Tutschulte 1976). Adult white abalone found in the wild are usually 13-20 cm long and inhabit 

substrate with little complexity (i.e. few cracks and crevices). Growth rates for adults (n=3) fed 

on Macrocystis have been measured at 16.4 ± 7.8 mm/ year in the laboratory (Tutschulte 1976). 

Adult abalone feed primarily on drift algae but will also feed on attached macroalgae, using their 

radula and mouth parts to graze algae from rocky substrates. Drift algae is captured with the 

anterior portion of the foot and brought to the mouth. Cephalic and epipodial tentacles are 

equipped with sensory capabilities for detecting the arrival of drifting alga fragments. 

Field estimates of mortality rates for adult white abalone have not been reported (Hobday and 

Tegner 2000). Natural sources of mortality include factors such as predation, disease, old age, 

and starvation. Abalone face a variety of predators, whose importance varies with location and 

the size-class of abalone. For example, filter-feeders will consume abalone at the egg and larval 

stages. Predation mortality by small crustaceans, sea stars and protozoans, however, is greatest 

during the post-larval stages (Leighton 2000). Typical predators on juveniles and adults include, 

cabezon (Gotshall 1977), starfishes, octopuses, spiny lobsters, crabs, sheephead, moray eels, bat 

rays, sea otters and humans. Field data on the predation pressure of non-human predators on 

white abalone are lacking. Abalone are important prey of sea otters; however, there is no 

evidence that sea otter predation has resulted in extirpation of abalone. For example, in Central 

California several abalone species (red, flat, pinto and black) co-exist with sea otters (Lowry and 

Pearse 1973, Cooper et al. 1977, Hines and Pearse 1982, Rogers-Bennett 2007). Similarly, the 

presence of sea otters may limit white abalone populations to small individuals that are restricted 

to cryptic habitats. 

Mortality due to senescence is thought to occur as white abalone approach ages between 35-40 

years. Many of the wild white abalone identified during the 1990s are thought to be >25 years 

old (Davis et al. 1996) and thus may be approaching the end of their expected life span. If these 

assumptions are true, a large proportion of the white abalone identified in nature during the 

1990s will die within the next decade (Hobday and Tegner 2000). 

Diseases associated with mortality of abalone in nature include withering syndrome, which 

resulted in mortality of >90% of the black abalone population in many areas (Friedman et al. 

1997). This bacterial disease infects the gastrointestinal epithelia of abalone and results in 

lethargy and loss of pedal mass. Withering syndrome occurs in other California abalone, 

including white abalone, but has been successfully treated with antibiotics in the laboratory. 

Withering syndrome is not, at present, considered a major factor in the decline of white abalone. 

However, the spread and virulence of withering syndrome is enhanced by higher than average 

sea water temperatures. Warmer water conditions associated with climate change and El Niño 
White Abalone Recovery Plan 

 BACKGROUND

I-14

events may thus result in increased manifestation of withering syndrome. 

Warmer water conditions associated with climate change and El Niño events may also be 

associated with decreased kelp growth (Tegner et al. 2001) as nutrient availability (e.g. nitrogen) 

is often inversely related to sea water temperature. Consequently, increased water temperature 

may deplete a major food source for adult white abalone (Tegner et al. 2001). Severe storms 

may also result in loss of standing stocks of kelp. Declines in growth or abundance of white 

abalone as a result of low food availability, however, have not been reported to date. 

Abundance and distribution of white abalone may have been affected by competition with sea 

urchins (Strongylocentrotus spp. and Lytechinus spp.) and sympatric abalone species. Past 

competition with pink abalone (H. corrugata) has been implicated in restricting the upper depth 

distribution of white abalone (Tutschulte 1976). Sea urchins and abalone are both herbivorous, 

thus increased abundance of sea urchins can result in increased competition for available 

macroalgae. Sea urchins and white abalone may also compete for available crevice space, since 

both are known to take refuge in rocky crevices. Alternatively, it has been suggested that sea 

urchins and abalone have a commensal relationship whereby urchins assist abalone in the capture 

of drift kelp. Densities of these co-inhabitants in areas where white abalone currently reside are 

low, and thus interactions with white abalone are thought to be minimal at this time. 

E. HABITAT CHARACTERISTICS

DISTRIBUTION Adult white abalone occur in open, low relief rocky reefs or boulder habitat 

surrounded by sand (Hobday and Tegner 2000). Suitable habitat is patchy, thus, the distribution 

of white abalone is also patchy. The historical range of white abalone extended from Point 

Conception, California to Punta Abreojos, Baja California, Mexico, with the historical 

population center located at the California Channel Islands. 

Adult white abalone may be found between 5-60 m depths, (Cox 1960), but current remnant 

populations are most common between 30-60 m depth. A recent survey by Butler et al. (2006), 

found the highest densities of white abalone at 40-50m depth. Factors controlling the depth 

distribution of white abalone are poorly known. Biological factors, such as competition and 

predation, have been implicated as factors controlling the upper limit, while water temperature 

and food availability have been implicated as factors controlling the lower limit (Hobday and 

Tegner 2000). Tutschulte (1976) speculated that white abalone may have been restricted to 

deeper waters (> 25 m) as a result of sea otter predation or competition from pink abalone. 

Human fishing activities may have also contributed to this deeper depth distribution. 

Whether the same habitat is used, or preferred, by both adult and juvenile white abalone, is 

unknown. There is some evidence that abalone may shift their depth distribution as they age. For 

example, studies in Australia suggest that H. roei juveniles (3-4 m depth) and adults (deeper 

depths) occupy physically different, and distant, habitat (Wells and Keesing 1990). In 

California, H. fulgens may move into deeper water with increasing age (Leighton pers. comm.). 
White Abalone Recovery Plan 

 BACKGROUND

I-15

Good adult habitat is presumed to be where they are currently found: at the sand/rock interface, 

in water deeper than 30 m. Historically, white abalone were described as a deep-water species 

(Cox 1960) although they have reportedly been found in water as shallow as 7 m on the 

mainland coast (Tutschulte 1976). Interviews with former commercial abalone divers also 

indicate that the majority of adult white abalone taken during the fishery occurred at the 

sand/rock interface and were located and targeted during daylight hours. The CDFG suggested 

that white abalone may have been lumped with the landings of pink abalone, because of missidentification or lack of reporting requirements, and therefore the range and specific locations of 

white and pink abalone may be different than what we currently infer from the CDFG landing 

data. For this reason and because fishing effort can not be expressed for the CDFG abalone data, 

the reported commercial landings of white and pink abalone in California may not accurately 

reflect their historic distributions and abundance. 

Current distribution and habitat use may be residual only, or may be indicative of where abalone 

successfully settled (e.g., preferred habitat). Some current sites may reflect longer-range 

transport (e.g., via floating kelp; Bushing 1994, McCormick et al. 2008), and not “historically 

preferred habitat”. For example, red and pink abalone have been observed, rafting on floating 

kelp, presumably as a result of kelp detachment while the abalones were foraging (Bushing 

1994).

ABUNDANCE AND QUALITY OF SUITABLE HABITAT The amount of suitable white abalone 

habitat is not well known. The bathymetry and substrate characteristics through much of the 

species’ range have not been adequately mapped. Estimates of the amount of available habitat 

have been based on the assumption that 3% of the sea floor is rocky substrate (Thompson et al. 

1993). Davis et al. (1998) estimated the area of rocky reef habitat at 25-65 m depths within the 

historic range of the species to total 966 ha and to total 752 ha within southern California. A 

more recent survey by Butler et al. (2006) found >3,000 ha of rocky substrate between 30-60 m 

in a limited area off the southern California coast. 

Impacts on and losses of white abalone habitat as a result of natural and anthropogenic factors 

are unknown (Hobday and Tegner 2000). Degradation or loss of habitat is not likely to have 

been a factor contributing to the decline in white abalone abundance. Factors such as pollution, 

harvesting of algae (e.g. Macrocystis pyrifera) and climate change have the potential to affect 

abalone habitat, but are not known to have affected white abalone habitat. For example, 

pollution may have led to the loss of kelp forest along the Palos Verdes Peninsula in the 1950s1960s (Tegner 1989, 1993). Pollution leading to the loss of food, along with other factors such 

as kelp harvest and poaching by recreational divers, and unusually high recruitment rates of sea 

urchins leading to competition between urchins and abalone, contributed to the decline of some 

shallow-water abalone populations (Leighton 1966). Climate change and related increases in 

sea-surface temperatures may also impact abalone via declines of giant kelp as a consequence of 

reduced nutrient levels (Tegner 1989). The effect of temperature, however, on white abalone or 

algal abundance at the depths where white abalone occur, is unknown. 
White Abalone Recovery Plan 

 BACKGROUND

I-16

F. CRITICAL HABITAT

Critical habitat has not been designated under section 4(a)(3)(A) of the ESA because it was 

determined to be “not prudent” to do so. The not prudent determination was made because there 

was concern that identifying critical habitat would disclose to the public those limited areas 

where surviving white abalone currently exist and that such an action would increase the threat 

of poaching to white abalone (66 FR 29048). 

G. REASONS FOR LISTING/CURRENT THREATS

LISTING FACTORS AND CURRENT THREATS 

(1) The Present or Threatened Destruction, Modification, or Curtailment of Habitat or Range 

Loss or modification of habitat is not likely to have been a factor in the decline of white abalone. 

Hobday and Tegner (2000) conclude that natural or anthropogenic white abalone habitat losses 

are unknown. Due to the isolation of the offshore islands off southern California and northern 

Baja California, anthropogenic impacts to white abalone habitat should be limited near the 

islands; however, the mainland habitat may have been affected to an ‘‘unknown extent’’ by a 

variety of unspecified land-based human activities. The potential impacts of future projects that 

could destroy, alter or curtail habitat, such as dredging operations, cable repairs/construction, 

liquefied natural gas terminal installation, and nearshore military operations, will have to be 

analyzed on a case by case basis. The protections afforded by the ESA should help to limit the 

threats posed by these types of anthropogenic activities and ensure that they do not pose a 

significant threat to the current or future status of white abalone. Historically, pollution did 

affect shallow water abalone habitat (i.e., giant kelp forests) along the Palos Verdes Peninsula in 

the 1950s which resulted in a decline in certain shallow water abalone populations (Leighton 

1966). Even though the source of that pollution (DDT) has been controlled, its long-term affects 

on abalone habitat in that area remain unknown. The effects of other heavy metal industrial 

pollution and the depths to which pollutants may have an impact, along the Palos Verdes 

Peninsula in particular, are unknown. 

Long-term or short-term changes in ocean conditions, particularly as they relate to water 

temperature, could affect both larval and adult abalone (Hobday and Tegner 2000), but neither 

direct nor indirect effects have been documented in the wild. Leighton (1972) examined the 

effect of water temperature on white abalone larval growth, settlement and survival and found 

that larval growth and survival were optimized between 14-18 o

C, but that larvae were not 

successful at 10-12 o

C. Short-term changes in ocean conditions due to El Niño events might 

raise sea surface temperatures (SSTs) above the optimum for larval growth and survival, and, 

due to cascading effects stemming from a decline in the Macrocystis canopy, could lead to 

poorer condition of adults (Tegner 1989). The long-term warming trend in SST in the eastern 

Pacific Ocean (Hayward 1997) may actually increase larval survival as SST approaches the 

optimum (14-18 o

C) for larval survival in the laboratory; however, SST rise could have a 
White Abalone Recovery Plan 

 BACKGROUND

I-17

negative effect on adults for the same reasons mentioned above. The previous discussion is 

based on effects due to changes in SST and assumes that long- and short-term changes in ocean 

conditions affect changes in water temperature at depth similarly. The influence of disease (i.e. 

withering syndrome) may increase during periods of warm water conditions (Moore et al. 2000). 

Overall the Recovery Team viewed suboptimal water temperatures as posing a moderate threat 

to white abalone, but had a low level of certainty that this threat was imposing high mortality 

risk.

Reduced food and/or substrate quality and quantity may have been a factor in the decline of 

white abalone because of competition for food and space with sea urchins and other abalone 

species. For instance, increasing trends in abundance of sea urchins (Strongylocentrotus 

purpuratus and S. franciscanus) could have limited the amount of algae available for juvenile or 

adult white abalone consumption (Hobday and Tegner 2000). Although these potential 

ecological interactions may have had an impact historically, the densities of these potential 

competitors are currently low in areas where white abalone remain and are no longer likely to 

limit white abalone abundance (Hobday and Tegner 2000). 

(2) Overutilization for Commercial, Recreational, Scientific, or Educational Purposes 

White abalone abundance has declined significantly throughout its range as a result of 

overutilization for commercial and recreational purposes. Hobday and Tegner (2000), as well as 

others (Estes and VanBlaricom 1985), suggest that white abalone in California were subject to 

‘‘serial depletion’’ by the commercial fishery during the early 1970s. Serial depletion occurs as 

fishermen shift from exploited to unexploited fishing areas due to local depletion. Due to their 

life history characteristics as long-lived, slow moving bottom dwellers with external fertilization, 

abalone are particularly susceptible to local and subsequent serial depletion. If female abalone 

are not within a few meters of males when they both spawn, the sperm will be too diluted by 

diffusion to fertilize the eggs (Davis et al. 1996). As local abalone density declines, the 

probability of successful fertilization and subsequent recruitment decreases. It is evident to 

recovery team members and abalone experts world-wide that the most significant threat to white 

abalone is related to the effects of low population density on continued white abalone 

reproduction, survival and recovery. 

White abalone catch data from California indicate that over 80 percent of the white abalone 

landings were taken from San Clemente Island. The offshore Tanner Bank and Cortes BankBishop Rock region provided 13 percent of the total catch. Between 1965 and 1975, over 25 

percent (average 43 percent) of the white abalone catch in each area came from a single year 

(Hobday and Tegner 2000). If harvest was sustainable, the portion of catch harvested each year 

at each location should have been more consistent over a period of years. Region-wide landings 

of white abalone peaked at 144,000 lbs (65,318 kg) in 1972 after only 3 years of commercial 

exploitation, and declined to less than 10,000 lbs (4,535 kg) in 1977. By 1978, white abalone 

landings were so negligible (<1,000 lbs or 454 kg) that CDFG no longer collected landings data 

for the species. It has been suggested that the increasing value of abalone may have contributed 
White Abalone Recovery Plan 

 BACKGROUND

I-18

to increased fishing pressure (Estes and VanBlaricom 1985, Hobday and Tegner 2000, Karpov et 

al. 2000). For example, the price of white abalone increased from about $2.50 per pound in 1981 

to about $7 per pound in 1993. As the catch of all abalone declined, the total and per-unit value 

of the harvest continued to increase. White abalone was usually the most valuable species and by 

1988, white abalone was worth twice the value of other abalone species (Davis et al. 1996). 

According to studies conducted by Babcock and Keesing (1999), recruitment failure occurred in 

H. laevigata when densities of adults fell below 0.3-0.15 per m2

 or when males and females were 

greater than 2 m apart from one another. Assuming that these critical densities for H. laevigata

populations are similar to those required for self-sustaining white abalone populations, intense 

fishing pressure is likely the primarily cause for producing critically low densities in populations 

throughout most of white abalone’s historic range in Southern California. Low density has likely 

led to repeated recruitment failure and reduced genetic diversity within and across populations of 

white abalone in California. 

(3) Disease or Predation 

Withering syndrome is a fatal disease of abalone, Haliotis spp. (Haaker et al. 1992) caused by a 

ricksettia-like bacterium that affects the digestive epithelium of abalone (Friedman et al. 2000). 

Disease transmission is thought to be density dependent (Friedman and Moore, pers. obs.). First 

detected in 1985, withering syndrome disease has significantly affected west coast abalone 

species, especially the black abalone. Withering syndrome also occurs in pink, red, and 

green abalone (Altstatt et al. 1996). Although no wild white abalone have been observed with 

withering syndrome or its causative agent (the intracellular bacterium, "Candidatus xenohaliotis

californiensis", Friedman et al. 2000), this species is susceptible to the disease in captive settings 

(Moore, Robbins, and McCormick pers. obs). Hobday and Tegner (2000) suggest that large 

numbers of empty white abalone shells should have been detected during the abalone surveys of 

the late 1980s if white abalone were significantly affected by withering syndrome. During the 

early 1990s, a few freshly dead white abalone with undamaged shells were observed near Santa 

Catalina (Tegner et al. 1996), but the cause of mortality is uncertain. To date only seven wild 

white abalone have been sampled for withering syndrome (all have tested negative) and 

information on susceptibility is based on captive progeny from wild brood stock. A large 

number of captively-bred white abalone at the Channel Islands Marine Resource Institute 

(CIMRI) recently (2002-2005) died and showed symptoms of withering syndrome. While 

withering syndrome may affect white abalone at some frequency in a captive setting, it is 

unlikely to have been a major factor in the decline of the species in the wild. 

Laboratory studies have confirmed that temperature is important in transmission and 

development of clinical disease (Friedman et al. 1997, Moore et al. 2000). Red abalone exposed 

to temperatures ~18° C develop clinical disease, while those held at ~15 °C remained healthy 

(Moore et al. 2000). Recent data from McCormick et al. (unpubl. data) indicated that white 

abalone reared at temperatures <12° C, while infected with the withering syndrome-bacterium, 

remained free of clinical disease. However, those reared at 15 or 18° C developed withering 
White Abalone Recovery Plan 

 BACKGROUND

I-19

syndrome and had heavy bacterial infections as compared to those held at 12° C. These data 

combined with the magnitude of losses experienced by white abalone that were not treated with a 

therapeutant to reduce bacterial infections suggest that this species is highly susceptible to this 

pathogen and this must be considered in the recovery plan. In addition, these data suggest that 

habitat selected for white abalone supplementation should consider the temperature regime of 

outplant sites as well as the health status and density of sympatric abalone. Although disease 

was not considered as a threat to the declines that led to listing of white abalone, it is clear that 

disease (especially withering syndrome) is a threat to effectively recovering the species. 

Withering syndrome research is necessary to determine: 1) what habitat parameters might lessen 

the likelihood of infection in the wild; 2) whether resistant animals exist in the population; and 3) 

which treatment protocols are most effective in eliminating the spread of withering syndrome 

from infected to healthy animals. 

Several abalone predators have been documented, including sea stars, fish (e.g. cabezon, 

sheephead), crabs, octopuses, and sea otters (O'Connell 1955, Gotshall 1977, Hobday and Tegner 

2000). Although increases in abundance of these predators could be related to declines in white 

abalone abundance, no information is available on the density of the invertebrate predators in 

white abalone habitat. Predation by sea otters is not likely to have been a major factor in the 

decline of white abalone due the absence of sea otters within the range of white abalone during 

their decline. In summary, there is no evidence that disease or predation contributed to the 

decline of white abalone, and the extent to which predation will influence recovery potential 

remains unclear (see section I. Known Biological Constraints/Needs). 

(4) The Inadequacy of Existing Regulatory Mechanisms 

White abalone experienced significant declines in abundance throughout its range as a result of 

commercial over harvesting, therefore harvest regulations for white abalone during the major 

period of its decline in the 1970s were clearly inadequate to conserve the species and maintain 

white abalone harvest at sustainable levels. The establishment of minimum size limits has been a 

strategy used worldwide to manage the harvest of abalone on a sustainable basis (Hobday and 

Tegner 2000). In California, minimum size limits were established for abalone that were greater 

than the size of sexual maturity which should have allowed for several years of reproduction 

before the animals reached legal harvest size. However, successful reproduction does not 

necessarily occur every year. If reproductive failure persists for several years, mature abalone 

could attain legal size and be removed by the fishery without having successfully reproduced. 

Other measures were taken to regulate the abalone fishery. California prohibited abalone harvest 

during a portion of the spawning season (January through March). While this measure was 

likely ineffective for most species of abalone, the closure period did overlap substantially with 

the white abalone spawning period. Other regulations, such as bag limits for recreational 

fishermen, and limited entry, were also implemented by California as abalone management 

measures. In 1970, California established a permit fee of $100 for both divers and crew 

members (Burge et al. 1975, cited in Hobday and Tegner 2000). The diver fee increased to $200 
White Abalone Recovery Plan 

 BACKGROUND

I-20

in 1975 and finally reached $330 in 1991. Relative to permit fees charged by other countries to 

harvest abalone (e.g., Tasmania, South Australia), these relatively low fees did not promote 

sustainable abalone fishing in California. In fact, none of these measures prevented serial 

depletion of white abalone nor promoted sustainable harvest practices in the 1970s. In 1996, the 

California Fish and Game Commission closed the California white abalone fishery to protect the 

surviving adults (Davis et al. 1998). 

NMFS does not have formal documentation that Mexico has closed its commercial white 

abalone fishery or limited white abalone fishing, although in a meeting convened in Ensenada, 

Baja California, Mexico in June 2003, the Instituto Nacional de la Pesca (INP) stated that 

Mexico currently does not issue permits for harvesting white abalone. In addition, the INP 

presented preliminary results from a status review of white abalone. The INP has identified 

areas along shore and at the offshore islands and banks that did or currently do contain white 

abalone based on responses to questionnaires that were sent out to the local abalone management 

zones (cooperatives). The INP, in cooperation with the cooperatives, and possibly NMFS, would 

like to ground truth these qualitative data by surveying specific locations with remotely operated 

vehicles and multi-beam sonar. 

The intentional capture of sub-legal abalone (i.e., poaching) before they contributed substantially 

to the population could have reduced the reproductive potential of white abalone (Hobday and 

Tegner 2000); however, this is not likely to have been a major factor in the decline of white 

abalone in California because the State required all commercially caught abalone to be landed in 

the shell. In Mexico, during a survey in 1973, a substantial portion of the commercial white 

abalone catch was found to be undersized. The impact of illegal white abalone harvesting as a 

factor of the species’ decline is difficult to evaluate in Mexico, but was probably not a major 

factor in California. Poaching could be a problem in California in the future if recovery actions 

are successful and populations recover and expand. Also, as we continue to learn more about 

white abalone populations in Mexico, we may learn that poaching was and is a factor affecting 

the species’ viability. Unintentional take of abalone may have resulted from accidental, severe, 

cutting of sub-legal sized white abalone (Burge et al. 1975) because abalone do not have blood 

clotting ability and may suffer mortality as a result (Cox 1962, Hobday and Tegner 2000). Even 

undersized abalone that are handled and replaced without being cut suffer a 2 –10 % mortality in 

the field due to increased capture rates by predators on individuals that have not yet had a chance 

to reattach to the substrate. 

Inadequate enforcement is another factor that may have contributed to the decline of white 

abalone and could continue to do so should populations recover and expand. The combined 

enforcement staff for the State and the Federal agencies is small and their ability to monitor 

potential poaching activities is very limited given the difficulty of accessing areas where white 

abalone currently persist and where they may be outplanted in the future. Increased funding and 

better coordination among the agencies may help resolve future enforcement challenges. 

(5) Other Natural or Manmade Factors Affecting Their Continued Existence 
White Abalone Recovery Plan 

 BACKGROUND

I-21

Some argue that hybridization of white abalone with other more abundant California abalone 

species could potentially lower white abalone population size (Hobday and Tegner 2000). 

Natural hybridization between other California abalone species and white abalone has been 

observed. Owen et al. (1971) found that disturbance, high sea urchin frequency, and low 

abundance of one parent species increased the frequency of abalone hybrids. However, because 

large numbers of white abalone hybrids have not been found in the wild, Hobday and Tegner 

(2000) conclude that hybridization of white abalone with other abalone species is unlikely to 

have led to a decline of the species. 

Now that it is known that white abalone are highly susceptible to withering syndrome (and 

potentially other pathogens) in captive settings, another emerging threat to the species is that of 

spreading disease through supplementing wild populations with captive-reared animals. As 

mentioned above, under “Listing Factor (3) - Disease or Predation”, the risk due to this threat can 

be minimized if directed research efforts reveal: 1) what habitat parameters might lessen the 

likelihood of infection in the wild; 2) whether resistant animals exist in the population; and 3) 

which treatment protocols are most effective in eliminating the spread of withering syndrome 

from infected to healthy animals. 

Another factor that has hindered the recovery of white abalone is an inability to implement 

conservation and research efforts for a variety of reasons including: limited funding; and lack of 

coordination among the agencies, academia, and non-governmental organizations. 

CURRENT THREATS

The following threats currently put the white abalone at risk of extinction and are listed in order 

of their magnitude (high to low). These threats will be considered during the recovery planning 

process. In addition, the recovery plan will identify critical research questions that must be 

answered in order to gain a better understanding of the basic biological and ecological needs of 

the species and ultimately, ensure its continued existence. 

° Critically low levels of abundance (< 0.1 % of the estimated pre-exploitation population size) 

resulting in increased distance between individuals and repeated recruitment failure (Allee 

Effects; Allee 1931). 

° Inability to implement conservation and research efforts 

° Inadequate enforcement 

° Reduced genetic diversity resulting in lower reproductive potential and fitness of wild 

populations 

° Spread of disease through supplementation 

° Illegal harvesting 

° Habitat modification through human activities 

° Habitat modification through environmental/climate change 
White Abalone Recovery Plan

 

I-22

Table 5. Threats assessment table for the wild population of white abalone in California. A=adult, J=juvenile, LC=current, F=future. Historic threats are those that occurred historically, but do not occur at present. Current thoccurring now. Future threats are those likely to affect white abalone over the next ten years. VH=very high, H=

L=low. Overall rankings range from 1-10, with 1 being the highest priority and 10 being the lowest priority. Threfer to the actions listed in Part IV of the recovery plan. 

Listing Factor Threat Source Key 

Ecological Attributes Affected 

Life Stage Affected 

Historic, Current or Future 

Severity Geographic 

Scope 

Level of Certainty that Species is affected 

RA

Substrate Destruction 

Dredging Cable Repairs 

Nearshore military 

operations 

Benthic community 

shifts 

Long and short-term 

climate change 

Mortality Reduced growth 

A, J, L C, F L L L 2

Suboptimal water temperatures and water quality 

Anthropogenic thermal 

(+ or -) effluent 

Long and short-term 

climate change 

Mortality Reduced growth 

A, J, L C, F M H L 2

Reduced food quantity and quality 

Long and short-term 

climate change 

Kelp harvest Competition 

Mortality Reduced growth 

A, J, L F M M M 2

Habitat destruction, modification, or curtailment 

Environmental pollutants/toxins 

Sewage Agricultural runoff Industrial waste 

Mortality Reduced growth 

A, J, L C, F L L L 2

Low density Historic overfishing 

Current distribution 

pattern 

Reproductive potential 

Overutilization A H, C, F VH VH VH 1

Reduced genetic diversity 

Historic overfishing 

Current distribution 

pattern 

Reproductive potential Mortality 

A H, C, F M H M 1

Disease Endemic bacterium 

and unknown 

Disease and Mortality A, J F M M M 4 Predation 

Predation Sea Otter, Fishes, 

Invertebrates 

Mortality Behavior Reduced growth 

A, J H (sea otter), 

C (fishes, inverts.), F (all predators) 

M M M 3
White Abalone Recovery Plan

 

I-23

Listing Factor Threat Source Key 

Ecological Attributes Affected 

Life Stage Affected 

Historic, Current or Future 

Severity Geographic 

Scope 

Level of Certainty that Species is affected 

RA

Inadequate Enforcement 

Inadequate funding 

and lack of coordination between agencies 

Indirect mortality 

A, J H, C, F H H M 5

Illegal Take Poachers/Accidental 

take 

Reproductive potential Mortality 

A, J H, C, F H H H 3

Inadequate Regulatory Mechanisms 

Inability to Implement Conservation and Research Efforts 

Inadequate funding 

and lack of coordination between agencies 

Indirect mortality 

A, J, L H, C, F VH H H 1

Hybridization Close proximity to 

congeners 

Reproductive potential Behavior Genetic integrity 

A, J, L C, F L L L 1

Disease transfer 

between captive and wild populations 

Mortality A, J F L-H* H H 4 

Other 

Supplementation 

Genetic interactions 

between captive and wild populations 

Reduced fitness 

A,J, L F L H L 4 
White Abalone Recovery Plan

 

I-24

Table 6. Threats assessment table for the captive population of white abalone in California. A=adult, J=juvenile

H=historic, C=current, F=future. Historic threats are those that occurred historically, but do not occur at presentthose occurring now. Future threats are those likely to affect white abalone over the next ten years. VH=very hi

M=medium, L=low. Overall rankings range from 1-4, with 1 being the highest priority and 4 being the lowest pr

actions refer to the actions listed in Part IV of the recovery plan. * Recall that some captive facilities are relying 

for spawning and rearing white abalone. 

Listing Factor Threat Source Key Ecological 

Attributes Affected 

Life Stage Affected 

Historic, Current or Future 

Severity Level of Certainty 

that Species is affected 

Recovery Action 

Habitat destruction, modification, or curtailment 

Suboptimal water temperatures* 

Long and shortterm climate 

change 

Mortality Reduced growth 

A, J, L C, F H M 4 

Overutilization Reduced genetic 

diversity 

Historic 

overfishing 

Reproductive potential Mortality 

A, J, L H, C, F H H 4 

Disease and Predation 

Disease Endemic 

bacterium and unknown 

Mortality A, J C, F VH H 4 

Catastrophic events Equipment failure 

Human error 

Mortality A, J, L H, F H H 4 

Inadequate security Illegal take 

Human error 

Mortality A, J,L H M M 4, 5 

Other 

Hybridization Breeding between 

congeners 

Reproductive potential Behavior Genetic integrity 

A, J, L C, F L L 4 
White Abalone Recovery Plan 

 BACKGROUND 

I-25

H. CONSERVATION MEASURES

The following are conservation measures that have been undertaken for white abalone. In some 

cases these conservation efforts are relatively new and may not have had time to demonstrate 

their biological benefit. In such cases, provisions for adequate monitoring and funding of 

conservation efforts are essential to ensure intended conservation benefits are realized. 

PRIVATE-PUBLIC PARTNERSHIPS

Due to concern over the depleted status of white abalone, a consortium of scientists, fishermen, 

conservation organizations, universities, federal and state agencies, and mariculturists in private 

enterprise joined together to develop and execute a plan to restore white abalone populations 

(Davis et al. 1998). The White Abalone Restoration Consortium (Consortium) developed a fourstep restoration plan: (1) Locate surviving white abalone by surveying historical habitat; (2) 

collect brood stock; (3) breed and rear a new generation of juveniles and ultimately, brood stock; 

and (4) reestablish refugia of self-sustaining brood stocks in the wild. Because nearly 25 years 

of artificially producing and outplanting juvenile and younger red abalone in California have 

failed to demonstrate effective population restoration, the Consortium advocated that captiveborn white abalone be reared until 4 years of age (>100 mm or 4 inches). 

Federal, state, and private grants and funds have recently supported white abalone submersible 

surveys and the establishment of an aquaculture facility specifically designed to breed white 

abalone in captivity and rear offspring to adulthood for outplanting to the wild. 

NATIONAL MARINE FISHERIES SERVICE CONSERVATION MEASURES FOR WHITE ABALONE

The NMFS, following the recommendations of the Consortium, has led efforts to locate 

surviving white abalone by surveying historical habitat in Southern California and Baja 

California, Mexico. In addition, NMFS has collaborated with partners to collect brood stock for 

a captive propagation and enhancement program, identified and characterized habitat that may be 

targeted for future enhancement efforts, and promoted outreach and education efforts by helping 

to develop displays at local aquaria. 

NATIONAL PARK SERVICE CONSERVATION MEASURES FOR WHITE ABALONE

The Channel Islands National Park has been monitoring natural variation in recruitment of 

abalone through the use of cinder block test modules since 1989 at a variety of locations and this 

monitoring has revealed important information regarding where to focus future enhancement 

efforts. The Channel Islands National Park has also collaborated with members of the 

Consortium to collect brood stock for a captive propagation and enhancement program and 

achieve outreach and education goals. 
White Abalone Recovery Plan 

 BACKGROUND 

I-26

NATIONAL MARINE SANCTUARY CONSERVATION MEASURES FOR WHITE ABALONE

The Channel Islands National Marine Sanctuary has provided important logistical and staff 

support for members of the Consortium to monitor abalone recruitment, collect broodstock for a 

captive propagation and enhancement program, and promote outreach and education goals for 

white abalone within the Sanctuary. 

STATE OF CALIFORNIA CONSERVATION MEASURES FOR WHITE ABALONE

Because the State required that abalone fishermen submit landings data, the precipitous decline 

of white abalone in the 1970s was documented. As mentioned previously, the State closed white 

abalone fishing in 1996, thereby eliminating the factor most responsible for the species’ decline. 

The closure of all abalone fisheries in southern California in 1997 has also reduced the likelihood 

of accidental harvest or poaching of white abalone in California. 

The CDFG has conducted and/or participated in several SCUBA and submersible surveys 

documenting the distribution and abundance of white abalone (1980-81, 1992-93, 1996-97, and 

1999). The data and information gathered from these surveys have contributed to a better 

understanding of the decline of white abalone. 

Despite these state conservation measures, the species may not survive without human 

intervention because most of the remaining individuals are too far apart to successfully 

reproduce. 

MEXICAN CONSERVATION MEASURES FOR WHITE ABALONE

There is information indicating that Mexico has closed its white abalone fishery; however, 

NMFS is unaware of other conservation measures that Mexico may be implementing to protect 

the species. Pursuant to 50 CFR 424.16, NMFS provided Mexico with a notification that it had 

published a Federal Register document proposing to list the white abalone which occurs along 

the coast of both the USA and Mexico, and also invited Mexico to provide any information or 

comments it may have on the proposal. In addition, NMFS requested that Mexico provide the 

agency with information on any conservation measures it may have implemented to protect the 

white abalone. 

In June 2003, a meeting convened in Ensenada, Baja California, Mexico between NMFS and the 

INP. The INP stated that Mexico currently does not issue permits for harvesting white abalone. 

Also, the Mexican Abalone Cooperativos (local abalone management zones) have generally not 

permitted white abalone harvest since about 1996. The INP presented preliminary results from a 

status review of white abalone. The INP has identified areas along shore and at the offshore 

islands and banks that did or do contain white abalone based on responses to questionnaires that 

were sent out to the Abalone Cooperativos. The INP, in cooperation with the Abalone 

Cooperativos, and possibly NMFS, would like to ground truth these qualitative data by surveying 
White Abalone Recovery Plan 

 BACKGROUND 

I-27

specific locations with remotely operated vehicles and multi-beam sonar. 

I. KNOWN BIOLOGICAL CONSTRAINTS/NEEDS

The main biological constraint for white abalone is that self-sustaining wild populations cannot 

be maintained, nor can damaged populations be restored, when adult densities drop below 

critical values. Indeed critically low densities have led to poor recruitment success over a period 

of three decades. Data collected by the National Park Service annually at the northern Channel 

Islands since the mid-1980's and from ROV/Submersible cruises conducted from 1980-1981, 

1990-1991, 1996-1997, 1999, and 2002 (Davis et al. 1996, Davis et al. 1998, Hobday et al. 2001, 

Lafferty et al. 2004, Butler et al. 2006) suggest that recruitment has been negligible since the 

early 1970s. The low numbers of surviving animals identified over the past 23 years (< 300 

animals summed over all years), absence of emergent adults in the smallest detectable size class, 

and the detection of primarily solitary animals that are greater than 150 mm and over 10 years 

old (Tutschulte 1976), lend evidence to support the “negligible recruitment” argument. In 

addition, aggregative behavior has never been observed in any of the California species 

(Leighton 2000). The white abalone fishery ended in the late 1970s according to CDFG records, 

even though it took another 15 years to officially close the fishery. Thus, cryptic stage juveniles, 

if there were any, should have been detected in surveys conducted over the past 30 years. The 

chances of successful recovery of the species are near zero if we do not take action now. The 

data that exist to date provides evidence that recruitment is negligible throughout most of the 

former range of white abalone and the current data on density from areas where they have been 

located suggest that they are not close enough together to spawn (85% of the animals identified 

in 2002 were separated by linear distances that exceeded 10 m). 

White abalone suffer from a variety of disadvantages many of which link back to the fact that 

this species has rarely been the focus of scientific investigation. White abalone habitat was 

remote enough to make scientific investigation logistically difficult, but not remote enough to 

deter commercial and recreational fishers from exploiting them. Thus, much of what we know 

about white abalone is inferred from research that has been conducted with other species. Some 

of the most pressing questions that remain for white abalone are: 1) What is the minimum size of 

a viable white abalone population? 2) What is the current genetic connectivity between surviving 

populations and what kind of connectivity might have existed historically? and 3) What 

ecosystem parameters are required for promoting healthy larvae, juveniles and adults that can 

survive in the wild? These questions are the most pertinent because they directly affect the 

course that recovery planning should take. 

With regard to question 1), it has been suggested for H. laevigata that densities between 2000-

3000 animals per hectare, maintained throughout the spatial extent of the population, are 

necessary to sustain the population under fishing pressure. For H. rufescens along the northern 

coast of California, 1000 animals per hectare is not viable, but 8300 per hectare is viable and 

sustains a recreational fishery (Rogers-Bennett pers. comm.). 
White Abalone Recovery Plan 

 BACKGROUND 

I-28

With respect to question 2) an examination of the connectivity among existing populations of 

white abalone can be assessed using population genetic data. Levels of connectivity are 

determined by analyses of multiple genetic markers scored on individuals sampled from different 

geographic locations. Some species of abalone show extensive population differentiation (hence 

low connectivity), while others show no genetic differentiation of populations (high 

connectivity). Recent studies suggest that connectivity of black abalone populations over large 

spatial scales is relatively low (Hamm and Burton 2000), but is likely maintained by occasional 

chance large-scale dispersal events, and connectivity on smaller spatial scales (i.e. between sites 

at San Nicolas Island) is somewhat greater (Chambers et al. 2005, Chambers et al. 2006). The 

situation in white abalone cannot be assessed until samples become available from multiple 

geographic locations. If genetic samples are available for animals collected prior to the fishery 

are available, then historic levels of connectivity can be estimated. It is unlikely, however, that 

enough historic samples exist to conduct these analyses. 

With respect to question 3), while we know something about temperature optima for white 

abalone larval survival and settlement in the laboratory, very little else is known about abiotic 

(e.g., temperature, current speed and direction, substrate type and rugosity) and biotic (prey 

availability, predation, competitive interactions) factors that may affect growth and survival of 

early life stages. It is possible that otters (and other predators) may influence the future recovery 

potential of white abalone. This concept, where prey species are regulated at very sparse 

densities by their predators, is known as a “predator pit” (Holling 1959, Morris 1963). “Predator 

pits” have been documented for a number of recovering species (zebras, rabbits, ungulates) and 

in at least one marine system (Baltic Sea cod; Bakun 2006). It is possible that this interaction 

may be relevant to predicting sea otter predation on abalone, however there is uncertainty about 

the likely patterns of interaction between sea otters and abalone in the context of abalone 

recovery. 

Three major limitations for the recovery of white abalone are 1) lack of funding for a captive 

propagation and enhancement program; 2) persistent disease problems at CIMRI since 2002; and 

3) an inability to identify mechanisms (i.e. adequate funding and streamlining of the permitting 

process) for establishing multiple scientific research and enhancement facilities, even though a 

team of international abalone experts has been recommending this approach since 2001. Time 

delays created by these issues have caused additional biological constraints for this species 

because most animals identified during the 1980's, 1990's and 2000's (roughly 80%) are now 

approximately 30 years old according to 1) Tutschulte’s (1976) growth model; and 2) evidence 

suggesting negligible recruitment since the 1970's. White abalone may live 40 years (Tutschulte 

1976), thus it was predicted that the species could go extinct within 10 years in the status review 

(Hobday and Tegner 2000). 
White Abalone Recovery Plan 

 RECOVERY STRATEGY

II-1

II. RECOVERY STRATEGY 

A. KEY FACTS AND ASSUMPTIONS

Although the state of California implemented a variety of fishing restrictions in the 1970s, 1980s 

and 1990s in an attempt to protect and conserve white abalone, the total population decreased to 

<0.1% of its estimated pre-exploited size by the late 1990s. Overfishing by commercial and 

recreational fishers and inadequate regulation of the fishery led to the decline of white abalone. 

In spite of the fact that the fishery has been closed since 1996, illegal take of the animals, 

disease, predation, and habitat degradation through long-term climate change pose the greatest 

threats to the conservation and recovery of the species. 

Research conducted during the 1990s suggested that even with the closure of the white abalone 

fishery in 1996 that: 1) white abalone remaining in nature were primarily > 2 m apart from one 

another (Davis et al. 1998); 2) most survivors observed were $ 13 cm in shell length (Davis et al. 

1998, Behrens and Lafferty 2005); and 3) the highest estimated densities recorded during the 

1990s were at least two orders of magnitude lower than estimated densities prior to the fishery 

(Hobday et al. 2001). During the 2000s ROV and multi-beam sonar surveys of two shallow 

banks off of the southern California coast revealed that the white abalone population may be 

higher on just two offshore banks in southern California (approximately 12,820 for Tanner Bank 

and approximately 7,360 for Cortes Bank) than was thought during the 1990s for California and 

Mexico combined (approximately 2, 600 animals; Hobday et al. 2001). In spite of the revised 

population estimate, the viability of animals in the wild remains uncertain because: 1) primarily 

large (>13 cm in shell length) animals were detected on the two offshore banks; and 2) most 

animals were >2 m apart from their nearest neighbor. 

Based on this information, the following conclusions were made: 1) surviving white abalone are 

too far apart from one another and occur in densities too low for successful spawning and 

therefore, their reproductive potential is near zero; 2) the size distribution of survivors and the 

morphology of their shells suggests that a major recruitment event has not been observed since 

the early 1970s and the animals are approaching the end of their lives. If these conclusions are to 

be accepted, then the following assumptions must be true: 1) observations of white abalone in 

nature are an accurate portrayal of the species occurrence, distribution and abundance in the wild 

(i.e., no size-dependent sampling biases); and 2) white abalone do not move enough (on the order 

of 10’s of meters) to form aggregations dense enough to spawn successfully. These assumptions 

lead to the ultimate assumption that animals in the wild are not reproductively viable and that 

substantial recruitment in nature has not and will not occur in the future. 

B. PRIMARY FOCUS AND JUSTIFICATION OF RECOVERY EFFORTS

The proposed recovery approach serves to address the most pressing gaps in our knowledge and 

targets the elimination of threats so that the recovery goals outlined in this plan have the greatest 

likelihood of being achieved. The recovery effort for white abalone will entail several foci, some 
White Abalone Recovery Plan 

 RECOVERY STRATEGY

II-2

of which will be conducted simultaneously and some of which will necessarily follow others. 

The first of these is the assessment and monitoring of wild white abalone populations. This is 

crucial to the recovery effort because more accurate estimates of abundance, habitat availability, 

growth and mortality, and a better understanding of the spatial distribution of animals, 

metapopulation and genetic stock structure, and habitat requirements are necessary for guiding 

the course of enhancement activities and protecting surviving populations. For instance, the 

course that enhancement of the wild population with captive animals will take is directly 

dependent on the outcome of monitoring studies and the outcome of studies that will be 

conducted with captive-reared animals. More accurate estimates of white abalone fecundity and 

fertilization success, effects of temperature, diet and habitat type on growth and survival, and a 

better understanding of the impacts of disease (withering syndrome) on captive and wild 

populations will provide insight on minimum viable population size and conditions for 

promoting optimal health of animals in the wild. 

Field monitoring of populations and their habitat will significantly improve our understanding of 

the current status of the white abalone population in California and optimistically, throughout the 

full extent of the white abalone range into central Baja California, Mexico. Carrying out this 

action is a high priority because the course of the other recovery actions will be defined by the 

outcome of long-term field monitoring. Improving the accuracy of available habitat estimates 

will provide better confidence in both historic and current estimates of abundance and density. 

Evidence of whether surviving populations are viable will become evident as emergent recruits 

are detected by sampling gears. Because successful recruitment may occur at a decadal scale, 

and because new recruits may be cryptic for a relatively long period of time (2-3 years), it is 

crucial that the surveys be conducted at multiple locations (areas where surviving white abalone 

populations have been identified in the recent past), annually, over the course of at least ten 

years. Better estimates of minimum viable population size will be derived over time as survey 

data accumulates. Understanding the size and age structure of white abalone populations will 

enable us to better evaluate recruitment, growth, and population integrity for conservation of this 

species. In addition, these data will provide information necessary to develop enhancement 

protocols. A better understanding of the existing genetic structure of the population is crucial for 

determining how many and over what spatial extent, populations should be established in order 

to consider delisting. If extant populations are identified at workable SCUBA diving depths, 

additional research priorities include: tagging studies to estimate individual rates of movement, 

growth and mortality and nearest neighbor analysis to determine the importance of spatial 

structure on viability of populations in the wild (Allee Effects; Allee 1931). 

Existing and potential white abalone habitat will be identified and characterized through acoustic 

remote sensing technology. Abiotic and biotic characteristics of the habitat that white abalone 

occupy (e.g., habitat type, temperature, current speed and direction, other species present) will 

also be collected during surveys to better understand which characteristics are important for 

promoting white abalone growth and survival at all life stages. 
White Abalone Recovery Plan 

 RECOVERY STRATEGY

II-3

Protection of populations and their habitat in the wild will occur by promoting the establishment 

of Marine Protected Areas (MPAs) that overlap with surviving populations and potential 

outplanting sites. Securing the financial support for the establishment of a stronger state and 

federal enforcement presence in the near-coastal waters of Southern California would promote 

the protection of surviving populations and populations that may be established in the future. 

Protection will be achieved through state and federal regulations that focus on populations in 

California. Pursuant to Section 3(16) of the ESA, white abalone is listed throughout their range 

from Pt. Conception, CA, USA, to Punta Abreojos, Baja California, Mexico. There will be a 

concerted effort to establish a white abalone technical advisory team within Mexico and to build 

relations with the Mexican government and Abalone Cooperativos over time to ensure the 

conservation and protection of white abalone populations in Mexico. The execution of this 

recovery action is crucial for eliminating or lessening the effects of threats on white abalone (i.e. 

habitat modification, illegal harvest). This action also promotes the protection and conservation 

of the entire kelp forest ecosystem of which white abalone are an integral part and upon which 

they depend for long-term survival. Long-term protection will also depend on public 

understanding and stewardship of the species. This will be accomplished through a public 

outreach program (see below).

Captive propagation for enhancement of wild populations will occur by continuing the effort 

begun prior to ESA listing to spawn captive white abalone and rear their progeny. Captive 

propagation of healthy white abalone is of equal importance to monitoring because most of the 

evidence to date suggests that white abalone are locally extinct throughout a significant portion 

of their range and because there is no evidence to suggest that surviving populations of white 

abalone in the wild are viable. The white abalone recovery team recommends that multiple 

scientific research and enhancement facilities, namely CIMRI, the Bodega Bay Marine 

Laboratory (BML), and the NOAA Southwest Fisheries Science Center (SWFSC), carry out 

these pertinent studies for white abalone because 1) each facility provides a unique set of 

scientific and culture expertise; 2) each facility possesses different capabilities in managing 

water quality, and therefore may possess different capabilities in maintaining healthy captive 

animals; and 3) housing captive animals in multiple locations offers a safeguard against losing all 

animals in the case of a catastrophic event. Captive propagation of white abalone will occur 

simultaneously with monitoring activities because of the time it will take to develop techniques 

for the production of healthy animals. The captive rearing program will expand by attaining 

additional broodstock to better reflect existing genetic diversity in natural white abalone 

populations. Reestablishment of white abalone throughout its former historic range, in densities 

high enough to be self-sustaining, will be achieved by placing captive-reared animals in the wild. 

This focus is directly dependent on conducting pertinent studies with captive-bred animals that 

determines the factors most important for promoting the health, growth, and survival of all life 

stages of white abalone. 

A captive propagation program is currently underway at CIMRI. This program which has been 

underway since 2000, has achieved broodstock holding, maturation, and spawning. Larvae, 

juveniles, and adult animals are being successfully raised on a large scale. There are currently 
White Abalone Recovery Plan 

 RECOVERY STRATEGY

II-4

five pedigreed families of abalone in the hatchery ranging in age from two months to two years. 

Care has been taken to maximize genetic diversity; however, the nascent breeding program is 

now seriously restricted by the present availability of only six wild broodstock. The decay in 

genetic diversity is inversely proportional to the effective population size and given this effective 

population size, each generation produced from these individuals will result in an approximate 

10% loss of genetic diversity (Hedrick et al. 2000). Recently, McGinnity et al. (2003) 

determined that in farmed raised populations of Atlantic salmon, attaining a broodstock 

population of at least 50 breeding pairs (single parent crosses = 1 male x 1 female) reduced 

losses in genetic diversity to 1% per generation. In order to maximize chances for survival and 

ability to adapt to environmental changes, it is important to maximize the genetic diversity (or 

avoid in-breeding) in captive populations. Although abalone are highly fecund individuals and 

are capable of producing over 100,000 progeny per spawn, it is necessary to retain adequate 

numbers from each spawn to attain recovery goals (achieve numbers for supplementation while 

maximizing genetic diversity). The ultimate goal of the captive propagation program is to 

produce white abalone for eventual outplanting. 

The recovery team recognizes that the collection of additional broodstock from the wild is 

necessary in order to maintain the genetic integrity of the captive propagation and enhancement 

program, but also realizes that this recovery action may pose risks of 1) further reducing wild 

white abalone density, and genetic diversity in California; and 2) further altering the age 

structure of the wild white abalone population in California. The recovery team built a simple 

deterministic model to assess the risk of extinction associated with removal of white abalone 

broodstock from the wild population in California over the next 100 years. The model assumes 

both optimistic (N=34,000; Butler et al. 2006) and pessimistic (N=1600; Hobday and Tegner 

2000) estimates of total population abundance and optimistic λ=1.0±0.1 and pessimistic 

λ=0.9±0.3 finite rates of population increase (Figure 7). For scenarios with captive management 

(B, C), the recovery team used values proposed by Scientific Research and Enhancement Permit 

applicants T. McCormick and J. Butler. In particular, the models assumes that 50 animals are 

removed in years 1-3, 20 animals are removed in year 4, and 500 and 1000 animals are 

reintroduced in years 5-6 and 7-15, respectively. This model predicted that the cumulative 

probability of extinction increases from 0 to 1 at a faster rate when no supplementation of the 

wild population (scenarios A, D) occurs regardless of whether optimistic or pessimistic values of 

N and λ are chosen. Even under the optimistic scenario, with no supplementation, extinction was 

likely to occur by year 50. Supplementation of the wild population with captive animals did not 

stabilize the population; however, this condition did extend the probable time to extinction by at 

least an additional 40 years. This analysis suggests that a captive propagation program would 

not likely cause the population to reach extinction at a faster rate than it would without 

supplementation and in fact, might extend the time to extinction in the wild. 
White Abalone Recovery Plan 

 RECOVERY STRATEGY

II-5

0

0.1

0.2

0.3

0.4

0.5

0.6

0.7

0.8

0.9

1

0 10 20 30 40 50 60 70 80 90 100

year

cumulative probabilty

A

B

C

D

Figure 7. Cumulative probability of extinction (CPE) for white abalone. CPE was estimated using a diffusion 

approximation of simulated time series based on 4 scenarios: with captive management (B,C) and without captive 

management (A,D) for optimistic (C,D) and pessimistic (A,B) scenarios regarding population status. For optimistic 

scenarios (C, D), we assumed λ=1, standard deviation for λ =0.1, and No=34,000. For pessimistic scenarios (A,B), 

we assumed λ =0.9, standard deviation for λ =0.3, and No=1600. For scenarios with captive management (B, C), 

we used values proposed by Scientific Research and Enhancement Permit applicants T. McCormick and J. Butler. 

In particular, 50 animals are removed years 1-3, 20 animals are removed year 4, and 500 and 1000 animals 

reintroduced for years 5-6 and 7-15, respectively.

The Team also recognizes that this model makes another important assumption; captive animals 

introduced into the wild have the same reproductive fitness and survivorship as wild white 

abalone and outplanted individuals used for enhancement will help achieve self-sustaining 

populations in the wild. McCormick et al. (1994) provides a review of the success of abalone 

outplanting studies up until 1992 (see his Table 2). Percent survival in these studies ranges from 

0-90% and seem to indicate that abalone outplanted at sizes > 40mm have the highest survival 

rates (but see Tegner and Butler 1985). Table 7 provides a summary of more recent studies 

(post-1993) that have reported survival rates of field planted, captive-reared abalone. If 500 

animals are outplanted for two years and then 1,000 animals are outplanted for each year 

thereafter (these are conservative numbers based on what was proposed by Scientific Research 

and Enhancement Permit applicants), it would take five years, with an annual outplanting 

survival rate of 5%, to replace the 170 broodstock removed from the wild. The list of references 

supplied below in Table 7 indicate that an annual survival rate of 5% is possible, especially given 

new methods being used around the world in abalone enhancement programs (e.g., improved 

condition of hatchery-reared animals, field planting at larger sizes, and new field planting 

modules). In addition, the broodstock would be replaced with younger animals that could 

potentially have higher reproductive potential than those removed from the wild.
White Abalone Recovery Plan 

 RECOVERY STRATEGY

II-6

Table 7. Summary of results of abalone field planting studies conducted around the world since 

1993. N= the number of abalone used to enhance the wild population. EPI= the estimated 

population increase presumably due to enhancement activities. 

Citation Species Location Size range 

(mm) 

N Survival EPI

Lapota (unpub. 

data) 

Haliotis fulgens Pt. Loma, 

CA 

70-100 200 77% after 2 months 

Rogers-Bennett 

and Pearse 

(1998) 

Haliotis rufescens Northern 

CA 

mean 8 50000 0-0.21% after two 

years 

126 

McCormick et 

al. (1994) 

Haliotis fulgens Santa 

Catalina 

mean 25 8000 40% after 3 months 

Lee et. al.(2002) Haliotis diversicolor NE 

Taiwan 

 3.59% in 1997 

5.13% in 1998 

16176 

20513 

Schiel (1993) Haliotis iris New 

Zealand 

3-30 80000 Annual range 1.2-

72.4% over two years 

Kojima (1995) Haliotis discus discus 

H. d. hannai 

H. diversicolor 

aquatilis 

H. d. diversicolor 

H. sieboldii

Japan 15-40 12-51% between 

1980-1985 

Seki and 

Taniguchi 

(2000) 

Haliotis discus hannai Japan mean 16.5-

24.5 

166000 26.7% after three 

years (1996-1998) 

10-20 360 9% after three years 

(2000-2003) 

James (2005) Haliotis rubra Australia 

13-26 940 32% after 8 months 

James (2005) Haliotis laevigata Australia 15-30 800 15% (artificial reef) 

and 10% (natural 

reef), after 2 years 

(2001-2003) 

Shepherd 

(2000) 

Haliotis laevigata Australia 50-60 50 Mean annual survival 

80% over six years 

Dixon et al. 

(2006) 

Haliotis laevigata Australia 28 8000 47-57% over nine 

months 
White Abalone Recovery Plan 

 RECOVERY STRATEGY

II-7

Development of an enforcement, public outreach and education plan will help to establish multidirectional sharing of information between the federal government, state and local government, 

constituent groups, academia, and the general public. This program will be established by 

encouraging the addition of staff and equipment to marine/coastal state and federal enforcement 

programs and by forming partnerships with local aquaria (e.g., Aquarium of the Pacific, Long 

Beach California, USA; Cabrillo Aquarium, San Pedro, California, USA; The Ocean Institute, 

Dana Point, California, USA) and non-profit organizations (e.g., CIMRI, Oxnard, California, 

USA). The primary goals of the program will be to: 1) educate the public on the important role 

abalone play in the kelp forest ecosystem; 2) reduce the occurrence of poaching and accidental 

take; and 3) aid in the protection of existing wild populations though public involvement in longterm monitoring. A public outreach and education program will help to raise awareness of the 

ecological and economic importance of abalone species with a focus on white abalone. Through 

an ecosystem-based initiative, a heightened sense of stewardship towards white abalone would 

naturally be incorporated into a program that focuses on the broader importance of maintaining 

healthy marine habitats that encompass the deeper rocky substrata habitats near the California 

coastal islands and outer banks (Pikitch et al. 2004). The program will aim to establish 

relationships with representatives from Congress, news media, constituent groups, state and local 

government, the Mexican government, environmental education and interpretive centers, 

academia, and the general public by convening workshops that focus on the program’s primary 

goals. 

Securing financial support for white abalone recovery must be underscored as a very important 

part of the recovery strategy. Without adequate financial support, few, if any, of the recovery 

activities outlined in this Plan will be implemented. Financial support can be achieved through 

federal and private grants and this has been and is currently being done in a number of cases 

(e.g., Hobday and Tegner 2000, Lafferty et al. 2004), however, these grants do not support longterm recovery and monitoring efforts. The costs associated with the recovery of white abalone 

are large and recovery, therefore, will depend on the acquisition of long-term funding. 

White Abalone Recovery Plan 

 RECOVERY GOALS, OBJECTIVES, AND CRITERIA 

III-1

III. RECOVERY GOALS, OBJECTIVES, AND CRITERIA 

A. RECOVERY GOAL

The goal of the recovery plan is to increase wild white abalone abundance in California to viable 

and self-sustaining levels such that the species can be downlisted to threatened status and 

subsequently removed from the Endangered Species List. 

B. RECOVERY OBJECTIVES

The first objective of the recovery plan is to improve our knowledge of the current status of 

white abalone in the wild so that extinction risks can be estimated and a plan can be 

developed for carrying out recovery actions in a way that will most efficiently achieve the 

delisting criteria. Achieving this objective is dependent upon identifying and monitoring white 

abalone populations and their habitat. Monitoring wild populations over time will yield more 

accurate information on spatial and temporal distribution, size structure, genetic structure, 

individual and population growth and mortality estimates, and habitat requirements of surviving 

white abalone. Captive propagation of white abalone will yield laboratory-derived information 

on the effects of abiotic (e.g., temperature, habitat type) and biotic (e.g., predator presence, food 

type, disease) factors on the growth and survival of white abalone from fertilization through 

maturation. In addition, these studies will provide estimates of fecundity and fertilization 

success. All of this information will help in defining minimum viable population size, 

establishing predictive models that can estimate risk of extinction, and will guide the course of 

the artificial enhancement program. 

The second objective of the recovery plan is to reduce or eliminate existing threats to white 

abalone in the wild. The most significant threat to white abalone is its low abundance and 

density in the wild. By continuing to monitor wild populations, more information concerning the 

severity of this problem will become available. Alleviating the problem will occur by enhancing 

wild populations with captive bred animals until a viable and sustainable population size is 

achieved. Inability to implement conservation and research and inadequate enforcement due to 

lack of coordination and funds will be one of the most difficult threats to overcome. The hope is 

that through outreach and education, public awareness of the white abalone’s plight will be 

raised and this will motivate state, federal and private organizations to work together and 

develop a budget framework that provides long-term financial support for white abalone 

recovery. The threat of disease (withering syndrome) will be minimized by conducting studies 

that aim to learn more about the effects of withering syndrome on captive bred white abalone and 

by designing a sound enhancement plan that ensures the release of only healthy animals into the 

wild. Preventing illegal take of white abalone through enforcement and the establishment of 

protected areas through state and federal legislation has already begun. Federal (ESA) and state 

(Abalone Recovery Management Plan) protections currently in place are helping to protect 

habitat that is being utilized by white abalone in the wild. Potential designations of protected 
White Abalone Recovery Plan 

 RECOVERY GOALS, OBJECTIVES, AND CRITERIA 

III-2

areas and critical habitat will be considered as the spatial extent of enhancement activities 

becomes fully conceived. 

The third objective of the recovery plan is to downlist and eventually delist white abalone 

by defining a safe population level (i.e., delisting criteria) which includes viable/sustainable 

subpopulations at a number of locations through out the former range of the species. In 

theory, this objective can be achieved most effectively, after the first objective has been 

accomplished. In reality, it is understood that this objective will have to be addressed prior to the 

completion of the first objective. Given this, adjustments in the definition of a viable and 

sustainable population and the number and locations of these populations will be made after 

more information is collected through implementation of the recovery plan. Once viable 

populations are established in the wild, their sustainability will need to be assessed through longterm monitoring and their protection will need to be ensured through enforcement and/or by 

establishing protected areas. 

C. RECOVERY CRITERIA

Recovery criteria apply to populations of white abalone in both the USA and Mexico (for 

geographic reference see Figure 8). The best available information must be used in order to 

ascertain whether the species has met the recovery criteria and all the criteria must be met in 

order to delist/downlist the species. 

Downlisting Criteria

Demographic Criteria 

Criterion 1: Density and Abundance 

A. Density of emergent (detectable by human observation without substrate 

disturbance) animals (short term) must be greater than 2,000 per hectare for 75% 

of the geographic localities. 

B. Maintain a total of 380,000 animals (Rogers-Bennett et al. 2002; Butler et al. 

2006) in the wild, distributed among all geographic localities in the USA and 

Mexico. 

Criterion 2: Size Frequency 

A. Proportion of size of emergent animals in 75% of geographic localities includes 

at least 85% intermediate-size animals (90 to 130 mm) 

B. Proportion of size of emergent animals in 75% of geographic localities includes 

no more than 15% large animals (>130 mm) 

Criterion 3: Trend 

A. Achieve a stable or increasing estimate of geometric population growth (λ≥1) for 

>75% of the geographic localities over a ten year period. 
White Abalone Recovery Plan 

 RECOVERY GOALS, OBJECTIVES, AND CRITERIA 

III-3

Criterion 4: Changes in distribution/reoccupation of historical range 

A. Reoccupation of white abalone over a spatial scale that encompasses their historic 

range such that 75% of the geographic localities in the USA and Mexico are 

reoccupied and meet the aforementioned recovery criteria. 

Threats-Based Criteria 

The threats criteria are organized according to the five ESA listing factors discussed in detail on 

pages 29-34 of this document. 

Listing Factor 1: Destruction, Modification, or Curtailment of Habitat or Range 

A. Destruction, modification, or curtailment of habitat or range was not an important 

factor in the decline of the species historically and is not believed to limit 

recovery of the population at this time. Currently, substrate destruction, 

suboptimal water temperatures, reduced food quantity and quality, and 

environmental pollutants/toxins are considered to be of relatively low severity and 

the effect of these threats on the species are relatively uncertain. In the future, 

potential risks imposed by substrate destruction may be averted through 

implementation of ESA Section 7 consultations and establishment of Marine 

Protected/Conservation Areas. The effects of long-term (or global) climate 

change on this species, either directly through water quality changes or indirectly 

through interactions with other species, including food items, is a potential threat 

to white abalone that cannot be addressed through these regulatory measures. At 

this time, it is unclear what effect long-term climate change will have on the 

species. 

Listing Factor 2: Overutilization for Commercial, Recreational, Scientific, or Educational 

Purposes 

A. In California, fishing for white abalone remains prohibited and regulations for 

other abalone species are designed to protect white abalone. In Mexico, no 

federal permits are issued that allow fishing for white abalone. These measures 

limit further reductions in density and genetic diversity; see Table 5. 

Enforcement of existing regulations and public outreach will help to minimize 

illegal harvest. 

B. The CDFG Abalone Recovery and Management Plan (ARMP) remains in place 

and reflects updated information adequately to ensure that white abalone will be 

managed to maintain demographic numbers outlined in this plan. There are 

assurances of adequate regulatory authority and funding for the state to implement 

the plan. 

Listing Factor 3: Disease/predation 

A. Routine monitoring results indicate no evidence of withering syndrome (WS)-

infected animals in wild populations. 
White Abalone Recovery Plan 

 RECOVERY GOALS, OBJECTIVES, AND CRITERIA 

III-4

B. The impact of any emerging disease has been evaluated and conclusions drawn 

that it is unlikely to significantly affect white abalone populations. 

C. A minimum of 50% of the white abalone geographic localities meeting the 

aforementioned demographic criteria, fall outside the resident range of sea otters. 

Listing Factor 4: Inadequate regulatory mechanisms 

A. An interagency (state/federal) task force is established to enforce regulations to 

protect established subpopulations and effectively alleviate illegal take of white 

abalone. 

B. Implementation of bilateral agreements with Mexico are continued and 

adequately deter illegal international trade. 

C. Future abalone harvest is monitored by the CDFG’s ARMP such that the health of 

the species is maintained and populations remain self-sustaining. 

D. Populations of white abalone in Mexico are adequately protected by regulatory 

mechanisms implemented by the Mexican authorities. 

Listing Factor 5: Other factors affecting the species’ continued existence 

A. Hybridization has been assessed and determined not to be a threat to the species. 

Long-term Monitoring Criteria 

Criterion 1: A monitoring program is in place and underway to evaluate population 

abundance and structure for a minimum of 50 years after downlisting. 

Criterion 2: A monitoring program is in place and underway to evaluate threats for a 

minimum of 50 years after downlisting/delisting. 

Criterion 3: A quantitative, long-term forecasting analysis plan is under development to 

ensure that probability of extinction in the wild is less than 10% in 100 years or 5 

generations, whichever is longer. 

Delisting Criteria 

Demographic Criteria 

 Criterion 1: Density and Abundance 

A. Density of emergent animals (short term) must be greater than 3,000 per hectare 

for 75% of the geographic localities (CDFG, 2005). 

B. Maintain a total of 500,000 animals (Rogers-Bennett et al. 2002, Butler et al. 

2006) in the wild, distributed among all geographic localities in the USA and Mexico. 

Maintenance of 500,000 animals is based on crude estimates of abundance necessary 

to sustain a 90% probability of persistence in 100 years, per IUCN guidelines. The 

model assumes a conservative estimate of λ= 0.90 (i.e., 10% decline per year). The 
White Abalone Recovery Plan 

 RECOVERY GOALS, OBJECTIVES, AND CRITERIA 

III-5

threshold value of 500,000 animals should be updated when empirical estimates of λ

become available. 

Criterion 2: Size Frequency 

A. Proportion of size of emergent animals in each geographic locality includes at 

least 85% intermediate-size animals (90 to 130 mm) 

B. Proportion of size of emergent animals in each geographic locality includes no 

more than 15% large animals (>130 mm) 

Criterion 3: Trend 

A. Achieve a stable or increasing estimate of geometric population growth (λ≥1) for 

>75% of the geographic localities over a ten year period. 

Criterion 4: Changes in distribution/reoccupation of historical range 

A. Reoccupation of white abalone over a spatial scale that encompasses their historic 

range such that 75% of the geographic localities in the USA and Mexico are 

reoccupied and meet the aforementioned recovery criteria. 

Threats-Based Criteria 

The threats-based criteria are the same as for downlisting. 

Long-term Monitoring Criteria 

Criterion 1: A monitoring program is in place and underway to evaluate population 

abundance and structure for a minimum of 50 years after delisting. 

Criterion 2: A monitoring program is in place and underway to evaluate threats for a 

minimum of 50 years after delisting. 

Criterion 3: A quantitative, long-term forecasting analysis plan has been developed to 

ensure that the probability of extinction in the wild is less than <5% within 100 years or 5 

generations, whichever is longer. 

Criterion 4: If information collected during the long-term monitoring period suggests: a) 

the decision to delist was in error, or 2) the species’ status has changed substantially, a 

status review of the species should be conducted. 
White Abalone Recovery Plan 

 RECOVERY GOALS, OBJECTIVES, AND CRITERIA 

III-6

 

Figure 8. Geographic localities of historic and/or current subpopulations of white abalone in the USA and MX 

based on fisheries catch data from the CDFG and the Mexican INP and Abalone Cooperativos. Oval shapes provide 

a general reference for geographic localities. Progressing from north to south the first locality covers the coastal 

region off of Santa Barbara and Ventura Counties. The next two localities comprise the Northern Channel Islands 

(offshore-San Miguel and Santa Rosa Islands; inshore-Santa Cruz and Anacapa Islands). The next group of 

localities are part of the Southern Channel Islands: San Nicolas, Santa Barbara and Catalina Islands (offshore to 

inshore, respectively), and San Clement Island to the south of Catalina. The next locality covers the coastal region 

off of southern San Diego County and the last locality in the USA encompasses Tanner and Cortes Banks. The 

northernmost locality in MX encompasses the Coronados Islands. The next locality covers the coastal region from 

south of Ensenada to Erendira. The next four localities encompass the islands of Isla San Martin, Guadalupe Island, 

Isla Cedros, and Isla Natividad. The final locality encompasses the coastal region of Bahia Tortugas.

Los Angeles 

San Diego 

Northern 

Channel 

Islands 

Southern 

Channel 

Islands 

Isla Cedros 

Bahia Tortugas 

Erendira 

Point Conception 
White Abalone Recovery Plan 

 RECOVERY PROGRAM 

IV-1

IV. RECOVERY PROGRAM 

A. STEP-DOWN OUTLINE

1 Assess and monitor white abalone subpopulations in the wild in cooperation with the state of 

California, other federal agencies, private organizations and the Mexican government 

1.1 Develop an assessment and monitoring program to identify current status of and 

track changes in wild subpopulations 

1.1.1 Assess extant subpopulations in the wild 

1.1.2 Monitor extant subpopulations in the wild 

1.2 Tag extant individuals belonging to multiple subpopulations 

1.3 Determine value of translocation to establish viable subpopulations and 

translocate if appropriate 

1.4 Conduct genetic analyses of wild population structure 

1.4.1 Determine extent of genetic differentiation among wild subpopulations to 

provide insight into structure 

1.4.2 Determine the best captive propagation, field planting and translocation 

design that serves to maintain the current genetic structure of the wild 

population 

1.5 Develop population data and demographic population viability analysis (PVA) 

models 

1.5.1 Evaluate and improve estimates of abundance, reproduction, survival, and 

growth for use in PVA models 

1.5.2 Develop population models to assess threats and identify key life history 

stages or demographic processes 

1.5.3 Conduct a PVA to determine time to extinction probabilities, trends to 

forecast the impact of threats, and the prospects for recovery 

1.5.4 Expand PVAs to incorporate demographic and environmental stochasticity 

1.6 Maintain and enhance communications with the Mexican government 

1.6.1 Establish a technical advisory team through the Instituto Nacional de la 

Pesca (INP) and invite the team to participate in workshops/meetings 

1.6.2 Participate in international conferences (e.g., International Abalone 

Symposium, MEXUS) 

1.6.3 Collaborate with Mexico to help improve our understanding of the status 

of extant subpopulations throughout the range and to help conserve and 

protect them 

1.7 Develop a Post-Delisting Monitoring Plan 

2 Identify and characterize existing and potential white abalone habitat through acoustic 

remote sensing technology 

2.1 Identify existing and potential habitat using multibeam sonar generated 

bathymetry data and quantify and revise estimates of habitat availability in 

California 
White Abalone Recovery Plan 

 RECOVERY PROGRAM 

IV-2

2.2 Generate ROV transect data to assess biological and physical attributes of habitat 

2.3 Determine the level of risk associated with habitat degradation/destruction that 

existing and potential viable populations (will) face 

2.4 Collaborate with Mexican researchers in assessing and monitoring white abalone 

habitat in Mexico 

3 Protect white abalone populations and their habitat 

3.1 Enforce State of California protections 

3.2 Enforce Federal ESA protections 

3.3 Protect white abalone populations and habitat as they are discovered or 

established through enhancement 

3.3.1 Continue state and federal review of permitted activities to minimize 

impacts to white abalone habitat 

3.3.2 Evaluate current and establish new conservation measures (e.g., fishing 

restrictions, conservation areas, etc.) to afford viable wild populations 

appropriate protection from habitat destruction and illegal take 

3.3.2.1 Support establishment of Marine Protected Areas in the northern 

Channel Islands 

3.3.2.2 Support maintenance of rockfish conservation areas 

3.3.2.3 Uphold objectives of the CDFG Abalone Recovery Management 

Plan 

3.3.3 Establish an interagency (state/federal) enforcement task force that can 

monitor areas containing viable populations on a semi-regular basis and 

protect them from illegal take 

3.4 Enhance degraded habitat through restoration or mollifying anthropogenic 

impacts through mitigation, as necessary 

4 Continue, refine and expand a captive propagation and enhancement program for white 

abalone in California with the goal of artificially enhancing populations in the wild 

4.1 Identify factors that may reduce the risk of mortality associated with the removal, 

handling and transport of wild white abalone to rearing facilities 

4.2 Determine the number of rearing facilities and broodstock animals needed to meet 

the goals of NMFS’ global management plans (e.g., Genetics, Disease, 

Disposition of Excess Individuals, and Field Planting; See Appendices B-E) 

4.3 Establish a standard for security measures at facilities housing broodstock and 

captive-reared animals 

4.4 Comply with and periodically update NMFS’ global management plans for a 

captive propagation and enhancement program 

4.4.1 Comply with updated genetics management plan 

4.4.2 Comply with updated disease management plan 

4.4.3 Comply with updated management plan for the disposition of excess white 

abalone 

4.4.4 Comply with updated field planting management plan 
White Abalone Recovery Plan 

 RECOVERY PROGRAM 

IV-3

4.5 Encourage partnerships with potential permit applicants who may be interested in 

participating in furthering the goals of the captive propagation program 

4.6 Enhance wild populations by outplanting captive-bred white abalone in selected 

sites throughout the range of the species 

5 Plan and implement public outreach and education plan 

5.1 Reduce likelihood of poaching by raising public awareness through outreach to 

regional fisheries management councils, industry groups, dive clubs/shops, and 

public media 

5.2 Develop educational displays and materials by cooperating with NGOs, aquaria, 

secondary schools, and universities 

5.3 Establish relationships with volunteer-based programs that can take part in 

various aspects of the captive propagation program (e.g., maintenance at 

hatcheries, research assistance, monitoring of captive-reared animals placed in the 

field etc.) 

6 Secure financial support for white abalone recovery 

6.1 Seek out and apply for federal, state, and private grants 

6.2 Form cooperative funding agreements among state, federal and private entities 
White Abalone Recovery Plan 

 RECOVERY PROGRAM 

IV-4

B. NARRATIVE

RECOVERY ACTION 1. ASSESS AND MONITOR SUBPOPULATIONS IN THE WILD IN 

COOPERATION WITH THE STATE OF CALIFORNIA, OTHER FEDERAL AGENCIES, PRIVATE 

ORGANIZATIONS AND THE MEXICAN GOVERNMENT. Our current understanding of white 

abalone population structure in the wild is minimal. Abundance and density estimates need 

refining and the long-term viability of surviving wild subpopulations is questionable. In order to 

establish recovery criteria for this species, a better understanding of the status of existing 

subpopulations in nature must be determined and then monitored over a period of time. This 

section of the recovery plan identifies the specific activities needed to establish confidence in the 

current status of the species and to better predict how wild populations will fare over short- and 

long-term time scales. 

1.1 Develop an assessment and monitoring program to identify current status of and 

track changes in wild subpopulations. NMFS, in association with other partners, will 

design an ROV survey program that focuses on the identification of surviving animals, 

recording individual position and size, and calculating reliable density estimates for white 

abalone in the wild. 

1.1.1 Assess extant subpopulations in the wild. White abalone are difficult to sample 

in the wild (most often occurring below depths of 30m at present) and therefore 

remote technologies must be relied upon to conduct surveys. Depth-stratified 

random ROV sampling over the course of 5 years will provide a standardized 

method for characterizing size-structure and estimating density of extant 

subpopulations. SCUBA surveys will also be designed for areas that contain safe 

diving depths. Estimates of the amount of available habitat (see Recovery Action 

2) in the wild in combination with reliable density estimates will improve current 

estimates of total population size in the wild. 

1.1.2 Monitor extant subpopulations in the wild. Once locations containing wild 

white abalone subpopulations have been identified during the assessment period, 

a plan for revisiting particular sites every 3 years over a ten to fifteen year period 

will be devised. NMFS in conjunction with the State of California will take the 

lead in organizing the agencies and their partners to conduct regular monitoring of 

the sites using ROV and SCUBA technology. Detection of changes in size 

distribution, abundance, and habitat will be the primary goal of the monitoring 

program. 

1.2 Tag extant individuals belonging to multiple subpopulations. If wild subpopulations 

of white abalone are detected in areas where SCUBA divers can access animals, NMFS 

and other partners will apply for a scientific research permit under Section 10 (a)(1)(A) of 

the ESA to tag individuals and track their movements and growth at least annually over a 
White Abalone Recovery Plan 

 RECOVERY PROGRAM 

IV-5

three year period. These pieces of information are critical to determining the viability of 

wild populations. 

1.3 Determine the value of translocation to establish viable subpopulations and 

translocate if appropriate. Translocation of wild white abalone may be attempted by 

the CDFG, NPS, NMFS, and other partners if 1) areas that support wild white abalone 

are identified; 2) subpopulations occur in areas that are amenable to repeated assessment; 

3) existing data suggests that the viability of the subpopulation is low if left 

unmanipulated; and 4) areas where predation and poaching pressures are minimal. 

Translocation experiments would involve tagging animals and translocating them so that 

the distances between the translocated individuals would be no greater than 2 m 

(Babcock and Keesing 1999). Translocated populations will be monitored for sizestructure, abundance, individual movements and individual growth on at least an annual 

basis over a five year period and then every two years for an additional five years. 

1.4 Conduct genetic analyses of wild population structure. Few data currently exist 

regarding the genetic structure of natural white abalone populations. Samples of 

approximately 20 field-collected animals, almost exclusively from a single southern 

California population, have been obtained and analyzed by Gruenthal and Burton (2005). 

Analysis of genetic variation at five nuclear microsatellite loci and partial sequences of 

one nuclear and two mitochondrial DNA genes suggests that significant genetic variation 

remains in natural populations. Variation at these marker loci (and others under 

development) can be used to assess the extent of population differentiation once samples 

from multiple locations become available. Genetic information is required for decisionmaking along two lines of recovery planning: 1) for determining whether there is high or 

low connectivity among surviving populations in the wild; and 2) for designing a sound 

captive propagation, field planting and translocation program where broodstock 

contamination is prevented and genetic markers are developed to track outplanted, 

captive-bred animals and their wild-bred progeny (Gruenthal and Burton 2005). 

1.4.1 Determine extent of genetic differentiation among wild sub populations to 

provide insight into structure. Collect tissue samples from at least 10 wild 

individuals belonging to each subpopulation. Sequence mtDNA and score 

polymorphic microsatellite loci. High levels of differentiation would suggest that 

connectivity of populations is low and that successful recovery of individual 

populations may not lead to recovery across other locales over decadal time 

scales. Such population differentiation also presents the possibility that 

geographically isolated populations may be locally adapted. 

1.4.2 Determine the best captive propagation, field planting and translocation 

design that serves to maintain the current genetic structure of the wild 

population. If high levels of population differentiation are detected, it would be 

undesirable to mix subpopulations during captive-breeding and field planting 
White Abalone Recovery Plan 

 RECOVERY PROGRAM 

IV-6

activities as these actions could potentially disrupt local adaptation and produce 

animals of unknown suitability to any locale. Hence, statistically significant 

allelic frequency differences will necessitate maintenance of separate stocks in the 

culture facilities and for subsequent field planting. 

1.5 Develop and refine population data and demographic PVA models. Quantitative 

methods are essential for recovery planning efforts. Population viability analyses (PVA) 

are a suite of tools that incorporate quantitative methods to predict population status. 

PVA may be used to assess extinction threats and guide the recovery and management 

process. In this plan, we have a need for improving the data needed for modeling efforts. 

Once these data are available they can be incorporated into population viability analyses 

to evaluate threats, population trends and make predictions about future trends. Elasticity 

analyses of matrix elements can be conducted to determine which elements impact 

population growth the most in the model. Identification of the most sensitive size classes 

and vital rates are valuable for the quantitative evaluation of research priorities, 

management policies and conservation strategies (Morris and Doak 2004). 

1.5.1 Evaluate and improve estimates of abundance, reproduction, survival, and 

growth for use in PVA models. There is a lack of data on white abalone 

abundances as well as population vital rates. Vital rates (growth, reproduction 

and survival rates) may be based more on animal size than on animal age as has 

been found for other abalone species. To build structured population models, 

which can add additional information compared with unstructured models, size 

specific vital rate data should be collected. Size specific vital rate data are 

available to estimate reproduction from one locale in southern California 

(Tutschulte 1976). Currently, there is a lack of data on growth and mortality. A 

research emphasis needs to be placed on acquiring growth and survival data for 

use in PVA. If these data can be collected for different size classes this would 

facilitate the creation of size structured population models. Estimates of variation 

around mean vital rates need to be expressed to facilitate the creation of stochastic 

PVAs. When possible, inclusion of sources of variation around the means need to 

be a priority. Evaluating stochasticity will be facilitated by knowing the mean 

vital rates examined for different size classes and different years. Identifying 

potential temporal stochasticity of the data collected needs to be included as a 

goal. Knowledge of how vital rates vary in response to different types of 

stochasticity can be incorporated into stochastic PVA. 

1.5.2 Develop population models to assess threats and identify key life history 

stages or demographic processes. For white abalone, we are hindered by the 

lack of quantitative data available for incorporation into population models, 

however there are some data available for congeners. Data from closely related 

congeners have been used for the construction of matrix models where data has 

been lacking (e.g. harbor porpoise populations) (Caswell et al. 1998). Size-based 
White Abalone Recovery Plan 

 RECOVERY PROGRAM 

IV-7

vital rate data information can be incorporated into deterministic matrix models to 

explore the impacts of different threats and recovery actions (Caswell et al. 1998, 

Ebert 1999, Morris et al. 1999). Perturbations of these models can reveal which 

rates influence population growth of the model the most (Benton and Grant 1999 

and references therein). These perturbations, prospective sensitivity analysis 

(Caswell 2000) have had far-reaching consequences for endangered species 

management. For example, perturbation analyses of loggerhead sea turtles, 

Caretta caretta, matrix models lead to a redirection of conservation efforts away 

from “headstarting” hatchlings (enhancing the survival of eggs in nests) toward 

the use of turtle exclusion devices in fishing nets (reducing adult mortality) 

(Crouse et al. 1987, Crowder et al. 1994). 

Abalone are long-lived, slow-growing species that may have similar population 

dynamics to sea turtles responding to perturbations in a stereotypical way 

(Heppell et al. 2000, Saether and Bakke 2000, Gerber and Heppell 2004). For 

management and recovery of white abalone it is critical to know which is higher, 

juvenile or adult survival elasticities. This has been identified as a research 

priority. The threats identified in this recovery plan include some that would 

impact certain vital rates and specific size classes. Perturbations of these 

elements in the matrix model can reveal which would have the most impact on 

population growth rate (λ). Those with the most impact on population growth 

would then be ranked higher then those with less of an impact. Similarly, 

perturbing different vital rates from different size classes can also be conducted to 

rank the potential efficacy of recovery actions assuming the model population. 

1.5.3 Conduct a PVA to determine time to extinction probabilities, trends to 

forecast the impact of threats and the prospects for recovery. Basic 

population viability analyses utilize count or abundance estimate data to examine 

trends in populations. To examine whether populations are growing or declining 

a minimum number of 10 years of population abundance estimates have been 

suggested (Morris and Doak 2004); although for long-lived species, such as white 

abalone, more than 10 years of estimates may be required. At this point, we do 

not have 10 or more years of abundance estimates, however we are working to 

establish a regular population survey program at areas with known wild 

populations. We have two years of abundance estimates generated for Tanner 

Bank, a key area for current remnant populations in the southern California Bight 

(Butler pers. comm.). Once a time series of abundance data is generated, these 

can be examined for trends. These trends can then be projected into the future to 

examine the probability of extinction over time. These types of extinction 

estimates will be critical for helping define recovery and delisting criteria as well 

as quantify the success or failure of recovery efforts. Quantifying recovery goals 

is an essential component of recovery planning. 
White Abalone Recovery Plan 

 RECOVERY PROGRAM 

IV-8

1.5.4 Expand PVAs to incorporate demographic and environmental stochasticity. 

Multi-site PVAs can incorporate metapopulation dynamics. Once deterministic 

PVA models are constructed for white abalone these may be expanded to include 

more realistic information such as demographic and environmental stochasticity; 

if the data these models require exist. Knowledge of correlations between the 

variation in vital rates and their contribution to population growth rate will be 

needed. For red abalone, we know that growth and reproduction are impacted by 

environmental stochasticity such as El Niño events and more long term 

environmental fluctuations. In the event spatially explicit demographic data is 

collected from multiple sites, these data may be used to construct multi-site 

PVAs. These types of models can be developed with and without information 

about movement between sites. 

1.6 Maintain and enhance communications with the Mexican government. A major need 

to restore wild white abalone populations throughout the former historic range of the 

species is to learn as much as possible about the historic and current status of white 

abalone populations in Mexico and efforts being made there to conserve and protect 

surviving white abalone, and to combine efforts (such as those outlined in 1.1-1.5) to 

conserve the species. At the National level, the INP designs, implements, and evaluates 

areas for commercial abalone fishing and aquaculture in Baja California, Mexico. The 

INP also prepares status reviews of species, recommends programs for use in issuing 

administrative orders to regulate fishery resources, and issues permits to local 

cooperatives that manage the fishery. Although the INP ceased issuing permits to allow 

commercial take of white abalone in 2001, the current status of populations in Mexico is 

largely unknown. 

1.6.1 Establish a technical advisory team through the INP and invite the team to 

participate in workshops/meetings. In order to learn more about the status of 

white abalone and conservation efforts currently underway in Mexico, NMFS will 

work through appropriate channels to request the formation of a Mexican 

technical advisory team. This team will be invited to participate in recovery team 

meetings so the recovery team can incorporate relevant information into recovery 

planning. 

1.6.2 Participate in international conferences (e.g., International Abalone 

Symposium, MEXUS). Through participation in international conferences, 

NMFS biologists and associated partners will maintain and expand contacts with 

abalone experts from inside as well as outside the INP. These connections will be 

extremely important to the recovery program in that research underway at 

universities, by local government, and other entities may be relevant to the 

recovery goals and criteria laid out in the recovery plan. In addition, participation 

at conferences will serve to inform Mexico of the efforts underway in the USA 

and potentially be the first step in establishing future collaborations. 
White Abalone Recovery Plan 

 RECOVERY PROGRAM 

IV-9

1.6.3 Collaborate with Mexico to help improve our understanding of the status of 

extant subpopulations throughout the range and to help conserve and protect 

them. Establishing a collaborative partnership between the USA and Mexico 

would be particularly beneficial to this species. Because of limited knowledge of 

the status of extant populations, the remoteness of their habitat, and limitations on 

funding sources in both countries, collaborations would help to better achieve 

goals for both countries including those laid out in this recovery plan. The time 

and financial burdens associated with assessing and monitoring extant populations 

throughout their range and ensuring the protection and conservation of those 

populations if discovered would undoubtedly be lessened if the two countries 

would work collaboratively. 

1.7 Develop a Post-Delisting Monitoring Plan. Section 4(g) of the ESA requires that 

NMFS work with the States to monitor the status of all species delisted due to recovery 

for a minimum of five years. The purpose of the post-delisting monitoring (PDM) plan is 

to confirm that white abalone does not require relisting as threatened or endangered 

during the period following removal of ESA protections. 

RECOVERY ACTION 2. IDENTIFY AND CHARACTERIZE EXISTING AND POTENTIAL WHITE 

ABALONE HABITAT THROUGH ACOUSTIC REMOTE SENSING TECHNOLOGY. Multibeam sonar 

generated high resolution (1 m) bathymetry maps can be used to accurately quantify the physical 

characteristics of habitats that support remaining wild white abalone. Calculating estimates of 

how much current and potential habitat exists is crucial to determining densities and to 

generating estimates of total population abundance. Creating maps that cover a large proportion 

of the historic range of the species will aid in determining where and how much suitable habitat 

remains. These elements are crucial to optimizing monitoring survey effort and to designing a 

successful enhancement program. ROV transects carried out through Recovery Action 1 will 

provide a visual record of the transect that can be reviewed for other physical and biological 

attributes of white abalone habitat. This data will also be important for selecting optimal sites 

for enhancement. Collection of water temperature, depth, and current speed and direction data 

will also contribute to the mix of physical attributes that may be used to better define suitable 

white abalone habitat.

2.1 Identify existing and potential habitat using multibeam sonar generated bathymetry 

data and quantify and revise estimates of habitat availability in California. The 

physical characteristics of suitable white abalone habitat must be better defined in order 

to prioritize habitat protection efforts and to establish foci areas for reestablished 

populations. Estimates of existing white abalone populations are based on applying 

observed densities to estimates of habitat area. The status review estimated a total of 750 

hectares of white abalone habitat in California. Multi-beam mapping of only three 

localities has revealed more than 3,000 hectares over the last three years. At least nine 

more localities remain to be mapped, which will increase the estimate of total white 
White Abalone Recovery Plan 

 RECOVERY PROGRAM 

IV-10

abalone habitat. Additional mapping will also provide information about potential field 

planting habitats that are more conveniently located for hatchery field planting 

operations. 

2.2 Generate ROV transect data to assess biological and physical attributes of habitat. 

ROV video tapes provide an inventory of associated fauna and flora. These tapes can be 

reviewed to identify other grazing invertebrates, potential abalone predators and food 

sources including red, brown and coralline algae. Habitat will also be classified by depth, 

substrate, algal cover, percent sand, and size of cobble and boulders. This information 

will be critical to choosing appropriate outplanting sites.

2.3 Determine the level of risk associated with habitat degradation/destruction that 

existing and potential viable populations (will) face. A complete inventory of white 

abalone habitat and populations throughout Southern California will allow managers to 

assess the current and future sublethal and lethal risks associated with the degradation or 

destruction of habitat. 

2.4 Collaborate with Mexican researchers in assessing and monitoring white abalone 

habitat in Mexico. Little is known about white abalone habitat or populations in 

Mexico. Previous meetings with Mexican officials have revealed a willingness on the 

part of the INP to cooperate in abalone recovery activities. Multibeam mapping 

technology and Remotely Operated Vehicles are not commonly available in Mexico and 

could be the basis of cooperative research programs. 

RECOVERY ACTION 3. PROTECT WHITE ABALONE POPULATIONS AND THEIR HABITAT. As 

identification of extant white abalone populations occurs and populations of captive-reared 

animals are established, measures must be taken to protect those populations and the habitats 

they depend upon. 

3.1 Enforce State of California protections. Protection of white abalone populations and 

habitat in the wild through State of California regulations is possible given that sport and 

commercial take of all abalone species is prohibited (since 1997) south of San Francisco 

(5522 California Fish and Game Code). This should conserve and protect remaining 

white abalone populations in southern California directly and also indirectly by ensuring 

that no accidental take of white abalone, mistaken for another species occurs. As of the 

date of this publication, all abalone fisheries south of San Francisco remain closed. As 

state laws are reevaluated in the future, measures to ensure conservation of white abalone 

will be taken. 

3.2 Enforce Federal ESA protections. Federal protection is provided by the ESA, most 

notably Section 9 whereby taking (i.e. harassing, harming, pursuing, hunting, shooting, 

wounding, killing, trapping, capturing, or collecting) a listed species by any person within 

U.S. waters is prohibited. It is also unlawful to attempt such acts, solicit another to 
White Abalone Recovery Plan 

 RECOVERY PROGRAM 

IV-11

commit such acts, or cause such acts to be committed. Regulations implementing the 

ESA (50 CFR §222.102) further define “harm” to include significant habitat modification 

or degradation that results in the killing or injury of wildlife by significantly impairing 

essential behavior patterns including, breeding, ,spawning, rearing, migrating, feeding or 

sheltering. Section 10 and Section 7 of the ESA and related regulations provide for an 

evaluation of federal and non-federal activities that may affect listed species and in some 

cases permission may be granted to authorize activities, otherwise prohibited under 

Section 9 of the ESA. For example, under Section 10 of the ESA, permits may be issued 

that allow scientific research and enhancement of a listed species. Section 10 also allows 

permits to be issued for take that is “incidental to, and not the purpose of, carrying out an 

otherwise unlawful activity” if NMFS determines that certain conditions have been met. 

Section 7 of the ESA requires federal agencies to consult with NMFS prior to 

authorizing, funding, or carrying out activities that may affect listed species. Section 7 

also requires that these agencies use their authorities to further the conservation of listed 

species. 

3.3 Protect white abalone populations and habitat as they are discovered or established 

through enhancement. All known naturally-breeding and outplanted populations of 

white abalone should be protected. Natural subpopulations represent the only known 

source of viability for the species, and outplanted subpopulations are a key component of 

the recovery program for the species and their persistence is thus crucial to the recovery 

of the species. Therefore all regulatory power provided by the ESA and by the State 

should be utilized, and voluntary activities by private and public entities should be 

encouraged. 

3.3.1 Continue state and federal review of permitted activities to minimize impacts 

to white abalone habitat. Multibeam mapping will provide new information on 

potential white abalone habitat. The resulting maps will provide detailed 

information to managers who must review permit applications for activities that 

may impact white abalone. 

3.3.2 Evaluate current and establish new conservation measures (e.g., fishing 

restrictions, conservation areas, etc.) to afford viable wild populations 

appropriate protection from habitat destruction and illegal take. A number 

of pre-existing conservation activities (proposed and underway) are designed to 

protect viable white abalone populations in the wild. However, each of these 

activities should be examined further to ensure they are as effective as possible. 

For example, management areas should be considered in the case that predation 

by sea otters or other predators is likely to inhibit recovery of abalone. An indepth examination of these activities may also conjure suggestions for minor 

changes to pre-existing activities, which if adopted by the controlling entity(ies), 

would benefit white abalone without additional financial or logistical burden. In 

addition, conservation measures should be expanded, as appropriate. 
White Abalone Recovery Plan 

 RECOVERY PROGRAM 

IV-12

3.3.2.1 Support establishment of Marine Protected Areas in the northern 

Channel Islands. Multibeam mapping of MPAs and ROV surveys will 

provide important inventories of habitat and endangered species within the 

MPAs. These inventories will help guide management as well as the 

design of future MPAs. 

3.3.2.2 Support maintenance of rockfish conservation areas. Multibeam 

mapping and ROV surveys will augment similar activities focused on 

rockfish resources. Coordinating mapping activities will increase the 

efficiency of both efforts. Critical habitat for white abalone exist within 

the Cowcod Conservation Area. These areas are rarely visited by 

enforcement officers; however, the co-location of an endangered species 

and protected fish populations reinforces the enforcement activity. 

3.3.2.3 Uphold objectives of the CDFG Abalone Recovery Management Plan 

(ARMP). The State ARMP serves to manage all of California’s abalone 

fisheries, prevent further population declines throughout California, and to 

ensure that current and future populations will be sustainable. Supporting 

many of the activities outlined in the ARMP will directly and indirectly 

contribute to the goals of white abalone recovery. 

3.3.3 Establish an interagency (state/federal) enforcement task force that can 

monitor areas containing viable populations on a semi-regular basis and 

protect them from illegal take. Poaching has been recognized as a serious threat 

to all abalone species including the white abalone. An identification of goals and 

strategies needs to be established between state and federal agencies. Clear 

definition of roles and responsibilities will prevent duplication of enforcement 

efforts. Abalone poachers must be prosecuted to the fullest extent of the law to 

discourage future poaching. It is also important to note that a primary role of 

enforcement is that of education. 

3.4 Enhance degraded habitat through restoration or mollifying anthropogenic impacts 

through mitigation, as necessary. Although habitat degradation was not identified as a 

significant threat to white abalone in the past or currently, future monitoring (habitat 

mapping and population assessment) may reveal areas that have been degraded. If these 

areas are occupied by surviving wild white abalone, or if they are potential outplanting 

sites because of other qualities they possess (e.g., logistical), then efforts may be made to 

restore the habitat to a state that would adequately support growth, reproduction and 

survival of white abalone. Additional restoration of degraded white abalone habitat, 

should it be identified, may also occur as mitigation for lost habitat due to any number of 

nearshore development projects (e.g., pipeline repair/construction, pier removal, liquefied 

natural gas terminal installation). Establishing and protecting areas that provide a high 
White Abalone Recovery Plan 

 RECOVERY PROGRAM 

IV-13

water quality refuge (i.e. in terms of water temperature or pH, for example) for white 

abalone may become increasingly important as the effects of long-term climate change 

manifest. In order to achieve this it may be appropriate to include the establishment and 

protection of such areas as mitigation for degraded water quality due to any number of 

nearshore activities (e.g., power plant operations, sewage outfall). 

RECOVERY ACTION 4. CONTINUE, REFINE AND EXPAND CAPTIVE PROPAGATION AND 

ENHANCEMENT PROGRAM FOR WHITE ABALONE IN CALIFORNIA WITH THE GOAL OF 

ARTIFICIALLY ENHANCING POPULATIONS IN THE WILD. 

4.1 Identify factors that may reduce the risk of mortality associated with the removal, 

handling and transport of wild white abalone to rearing facilities. A preliminary plan 

(White Abalone Collection and Handling Protocol; see Appendix A) outlining the 

measures that must be taken in order to reduce the risk of mortality associated with the 

removal, handling and transport of wild white abalone to rearing facilities has been 

developed and will be updated over time. Given that opportunities to collect broodstock 

may be severely limited, there is a strong need for identifying factors that will maximize 

survival rates of broodstock at captive rearing facilities. 

4.2 Determine the number of rearing facilities and broodstock animals needed to meet 

the goals of NMFS’ global management plans (e.g., Genetics, Disease, Disposition of 

Excess Individuals, and Field Planting; see Appendices B-E). The above-mentioned 

management plans have guided and will continue to guide decisions on the number of 

rearing facilities and broodstock animals necessary for the recovery of the species. The 

White Abalone Recovery Team recommends that multiple scientific research and 

enhancement facilities, such as CIMRI, BML, and the NOAA SWFSC, be designated for 

white abalone rearing because 1) each facility provides a unique set of scientific and 

culture expertise; 2) each facility possesses different capabilities in managing water 

quality, and therefore may possess different capabilities in maintaining healthy captive 

animals; and 3) housing captive animals in multiple locations offers a safeguard against 

losing all animals in the case of a catastrophic event. 

4.3 Establish a standard for security measures at facilities housing broodstock and 

captive-reared animals. A plan outlining the security measures that must be taken at all 

facilities housing broodstock and captive-reared animals will be developed and updated 

over time. There is a strong need for developing these standards in order to prevent the 

introduction and/or spread of disease and to eliminate the possibilities of mortality due to 

catastrophic events. See Appendix A and C for a summary of some measures that are 

already being taken.

4.4 Comply with and periodically update NMFS global management plans for a captive 

propagation and enhancement program. After consultation with experts on genetics, 

disease and disposition of excess individuals, field planting management plans will be 
White Abalone Recovery Plan 

 RECOVERY PROGRAM 

IV-14

revised to guide various aspects of the captive breeding program in accordance with ESA 

section 10 (a). 

4.4.1 Comply with updated genetics management plan. Consideration should be 

given to the genetic aspect of the enhancement program. Captive breeding 

programs should reflect the genetic structure of wild abalone populations. If this 

is not possible, care should be taken to maximize the genetic diversity of 

hatchery-raised abalone and consider the potential genetic influence (e.g. dilution) 

of the number of abalone planted in any area. Genetic variability should be 

maintained within the pool of hatchery-raised abalone. To achieve this, the pool 

of broodstock should be maximized and single parent matings used to create 

individual families. In addition, pedigrees of all family lines should be 

maintained to avoid inbreeding among hatchery stocks. To ensure approximately 

equal representation of each family created, approximately equal numbers of 

offspring from all pair crosses should be maintained until planting in the wild. 

However, genetic diversity of broodstock should not limit the continuation and 

expansion of captive propagation. When appropriate, captive-bred animals 

should be returned to field locations. Although it is impossible to prevent genetic 

adaptation to hatchery conditions, one may minimize these impacts through the 

maintenance of family lines and planting equal numbers from each family thereby 

allowing natural selection in the field to ensue. See Appendix B for further detail.

4.4.2 Comply with updated disease management plan. In order to reduce disease 

risks culturists must adhere to established husbandry protocols outlined in the 

Disease and Parasite Management Plan (see Appendix C). Technicians working 

with broodstock will be trained to practice good husbandry techniques. Water 

flowing into tanks should be filtered and UV irradiated at levels safe for larvae 

and very early life stages. Water quality will be monitored (e.g., temperature, 

salinity, dissolved oxygen) on a daily basis. New broodstock will be quarantined 

for a period of six weeks, tested for disease, and treated if infected. A subsample 

of captive-bred individuals will be tested on a semi-annual basis for disease (e.g., 

by histology). The likelihood of introducing pathogens will be reduced by surface 

cleaning kelp with freshwater prior to placement in tanks. Heritability of 

resistance traits will be ascertained and if observed the use of such families for 

outplanting will be evaluated. Access to captive rearing facilities will be limited 

to only authorized personnel and approved visitors. All potential holding 

facilities will be required to be free of specific diseases and parasites (e.g., 

withering syndrome, sabellid worms). 

4.4.3 Comply with updated management plan for the disposition of excess white 

abalone. White abalone are broadcast spawners, producing millions of embryos 

during a single spawn. In the course of hatchery operation, it is common that 

more abalone are produced than can be utilized for outplanting or can be 
White Abalone Recovery Plan 

 RECOVERY PROGRAM 

IV-15

reasonably maintained within the hatchery. Valid uses of surplus animals include 

experimental stocking in the ocean as postlarvae and juveniles (0.3 – 35 mm shell 

length), life history research (e.g. estimates of fecundity, fertilization success 

rates, and recruitment rates under a range of biotic and abiotic conditions), and 

public display. Experimental outplanting will provide useful information 

regarding stock enhancement practices. Research is needed to provide crucial 

data on biological and environmental requirements (e.g. effects of temperature, 

diet, substrate type, and presence of predators) in a laboratory setting for drawing 

inferences about growth and survival in the wild. See Appendix D for more 

detail.

4.4.4 Comply with updated field planting management plan. To assess the optimal 

approach to outplanting, a program of research should be implemented that will 

determine: 1) optimal size at stocking under a range of conditions in order to 

minimize risk of mortality at outplanting; 2) prior to outplanting, variables such as 

benthic habitat type, depth, food availability, predators and conspecifics should be 

characterized to aid in the selection of outplanting sites; 3) survivorship and 

population structure should be evaluated following release into the wild, as part of 

a post-release monitoring program; 4) release modules should be used to 

minimize abalone stress and protect them from predation during the initial 24 

hour release period; and 5) a plan should be developed in cooperation with the 

state, other federal agencies, and private industry to monitor the effectiveness of 

the field planting program and the recovery rate of enhanced/established 

subpopulations. See Appendix E for more detail.

4.5 Encourage partnerships with potential permit applicants who may be interested in 

participating in furthering the goals of the captive propagation program. The 

recovery team has recommended that the captive propagation program be comprised of 

multiple facilities because: 1) each facility provides a unique set of scientific and culture 

expertise; 2) each facility possesses different capabilities in managing water quality, and 

therefore may possess different capabilities in maintaining healthy captive animals; and 

3) housing captive animals in multiple locations offers a safeguard against losing all 

animals in the case of a catastrophic event. Also, as enhancement efforts proceed and 

expand, the participation of multiple partners in tracking the survival of outplanted 

animals both over the short- and long-term will become ever more important.

4.6 Enhance wild populations by outplanting captive-bred white abalone in selected 

sites throughout the range of the species. A program of research is being implemented 

to determine: 1) optimal size at stocking under a range of conditions in order to minimize 

risk of mortality at outplanting; 2) the selection of outplanting sites based on which 

benthic habitat types, depths, food quality and quantity levels, and predator and 

conspecific densities lead to highest survival rates; 3) survivorship and population 

structure following release into the wild, as part of a post-release monitoring program; 4) 
White Abalone Recovery Plan 

 RECOVERY PROGRAM 

IV-16

which type of release modules minimize abalone stress and protect them from predation 

during the initial 24 hour release period; and 5) how to develop a cooperative plan that 

monitors the effectiveness of the field planting program and the recovery rate of 

enhanced/established subpopulations. See Appendix E for more detail.

RECOVERY ACTION 5. PLAN AND IMPLEMENT A PUBLIC OUTREACH AND EDUCATION PLAN. 

Public outreach and education are vital to the recovery of white abalone. These activities raise 

awareness and promote individual responsibility and stewardship of the species. These activities 

should include both visual and audio elements to reach the greatest number of individuals.

5.1 Reduce the likelihood of poaching by raising public awareness through outreach to 

regional fisheries management councils, industry groups, dive clubs/shops, and the 

public media. Identify potential stakeholders and interest groups for outreach efforts. 

Participate at meetings and conferences to establish and solidify relationships with 

partners. There is an immediate need for an information brochure to distribute to the 

public through cooperating partners. 

5.2 Develop educational displays and materials by cooperating with NGOs, aquaria, 

secondary schools, and universities. The NOAA Public Affairs Office and Southwest 

Regional Office should work to promote abalone issues on a nationwide and regional 

basis highlighting the global perils that abalone species face and the fact that white 

abalone is the first marine invertebrate to be listed as endangered under the ESA. Efforts 

to develop white abalone videos for distribution to the media and for placement on web 

sites should be promoted to help raise public awareness. Public aquaria have been 

identified as potential grow out facilities for research and enhancement activities and this 

will also serve to raise public awareness. Although collection of broodstock is being 

restricted to captive propagation/outplanting programs, the progeny may be utilized in 

public education programs. These programs must be incidental to research and 

enhancement activities, but are recognized as an avenue for furthering outreach and 

education goals. 

5.3 Establish relationships with volunteer-based programs that can take part in various 

aspects of the captive propagation program (e.g., maintenance at hatcheries, 

research assistance, monitoring of captive-reared animals placed in the field etc.). A 

goal of each captive rearing facility should be to participate in education and outreach 

efforts. Volunteer-based programs have been recognized as a vehicle for securing low 

cost support from the members, enabling the public to become active participants in the 

recovery effort. Responsibilities of the individual will be determined based on the 

person’s qualifications. 

RECOVERY ACTION 6. SECURE FINANCIAL SUPPORT FOR WHITE ABALONE RECOVERY. A 

strong financial base is crucial to accomplish the criteria established in this plan. Assessment 

and monitoring of wild populations, conducting a captive propagation program, and developing 
White Abalone Recovery Plan 

 RECOVERY PROGRAM 

IV-17

an outreach program will require considerable funding to achieve this plan’s goals and 

objectives. Currently available funding is inadequate, and must be increased, particularly in the 

area of monitoring and propagation, which involves ship time, reliance on equipment that 

requires maintenance and upkeep, and the holding of numerous abalone for long periods. 

Funding has been unreliable in the past and a long-term financial commitment to continuing field 

monitoring and a propagation program must be consistent in order to recover this species. Below 

we identify potential sources for obtaining necessary funding support. 

6.1 Federal, state, and private grants. Currently, the white abalone program has obtained 

funding from a variety of federal, state, and NGO sources, including in-kind matching 

funds. Examples of funding sources include Saltonstall-Kennedy Funds, National 

Undersea Research Program, California Sea Grant, National Fish and Wildlife 

Foundation, Marine Conservation Biology International, The Nature Conservancy, and 

various oil and power company mitigation funds. Unfortunately, single entities alone 

cannot support the entire white abalone recovery effort. Typically, the funding scope of 

one grant can cover the costs of only a subset of the actions necessary to recover the 

species. As the white abalone recovery program is implemented, there will be an 

increasing need to secure long-term funding for monitoring the species’ status over a 

timeframe that encompasses several decades.

6.2 Cooperative funding agreements among state, federal and private entities. 

Cooperative agreements formed between and within state, federal, and private programs, 

where resources and expertise are pooled, may help avoid redundancy in effort and 

extend the scope of available funds.

White Abalone Recovery Plan 

 IMPLEMENTATION SCHEDULE 

V-1

V. IMPLEMENTATION SCHEDULE 

The Implementation Schedule that follows outlines recovery actions and estimated costs for the 

recovery program for the white abalone over a five-year period. The Implementation Schedule 

provides projections on which actions may continue beyond year five, but because we can not 

predict the recovery date for white abalone at this time, we can not state the exact duration of 

some of the recovery actions. The Implementation Schedule is a specific guide for carrying out 

recovery actions over a five-year period in terms of action priorities, action numbers, action 

descriptions, duration of actions, the parties responsible for actions (either funding or carrying 

out), and estimated costs in order to meet the recovery goals outlined in this plan. Parties with 

authority, responsibility, or expressed interest to implement a specific recovery action are 

identified in the Implementation Schedule. When more than one party has been identified, the 

proposed lead party is indicated by an asterisk (*). The listing of a party in the Implementation 

Schedule does not require the identified party to implement the action(s) or to secure funding for 

implementing the action(s). 

Recovery actions and descriptions reflect the actions as numbered in the Stepdown Outline and 

Recovery Narrative. Priorities in the Implementation Schedule are assigned as follows: 

Priority 1 – An action that must be taken to prevent extinction or to prevent the species from 

declining irreversibly in the foreseeable future. 

Priority 2 – An action that must be taken to prevent significant decline in species 

population/habitat quality or some other significant negative impact short of extinction. 

Priority 3 – All other actions necessary to provide for full recovery of the species. 

KEY TO IMPLEMENTATION TABLE ABBREVIATIONS

Abalone Recovery and Management Plan ARMP 

Bodega Bay Marine Laboratory BBML 

Cabrillo Aquarium CA 

California Department of Fish and Game CDFG 

Channel Islands Marine Resources Institute CIMRI 

Channel Islands National Marine Sanctuaries CINMS 

Endangered Species Act ESA 

Instituto Nacional de la Pesca INP 

Long Beach Aquarium of the Pacific LBAOP 

Montana State University MSU 

National Marine Fisheries Service NMFS 

National Park Service NPS 

Non-governmental Organizations NGOs 

Population Viability Analysis PVA 
White Abalone Recovery Plan 

 IMPLEMENTATION SCHEDULE 

V-2

Remotely Operated Vehicle ROV 

Santa Barbara Museum of Natural History SBMNH 

Self-Contained Underwater Breathing Apparatus SCUBA 

University of California San Diego UCSD 

University of Washington UW 

Withering Syndrome WS 
White Abalone Recovery Plan

 IMPLEMEN

V-3

IMPLEMENTATION SCHEDULE 

White Abalone (Haliotis sorenseni) 

Recovery Estimated Fiscal Year CosAction Number 

Action Description Priority 

Number

Action Duration 

Responsible Parties FY1 FY2 FY3 FY4 

1.1 Develop an assessment and 

monitoring program to identify current status of and track changes in wild subpopulations 

 FY1-FY5 

and beyond 

See breakdown of costs below 

1.1.1 Assess extant 

subpopulations in the wild (ROV and SCUBA) 

1 FY1-FY5 

and beyond 

250 250 250 250 

1.1.2 Monitor extant 

subpopulations in the wild (ROV and SCUBA) 

1 FY2-FY5 

and beyond 

NMFS, CDFG, NPS, CINMS, 

 150 150 150 

1.2 Tag extant individuals 

belonging to multiple subpopulations 

2 FY1-FY5 10 5 5 6 

1.3 Determine value of 

translocation to establish viable populations 

3 FY1-FY5 

NMFS, CDFG, NPS 

5 5 6 6 

1.4 Conduct genetic analyses of 

wild population structure 

 FY1-FY5 UCSD See breakdown of costs below 

1.4.1 Determine extent of genetic 

differentiation among wild subpopulations to provide insight into structure 

1 FY1-FY5 UCSD 25 25 25 25 

1.4.2 Determine the best captive 

propagation, field planting and translocation design that serves to maintain the current genetic structure of 

1 FY1-FY5 UCSD, 

NMFS, CIMRI 

10 10 10 10 
White Abalone Recovery Plan

 IMPLEMEN

V-4

IMPLEMENTATION SCHEDULE 

White Abalone (Haliotis sorenseni) 

Recovery Estimated Fiscal Year CosAction Number 

Action Description Priority 

Number

Action Duration 

Responsible Parties FY1 FY2 FY3 FY4 

the wild population 

1.5 Develop population data and 

demographic PVA models 

 FY3-FY5 

and beyond 

NMFS, CDFG, NPS, CIMRI, BBML, MSU 

See breakdown of costs below 

1.5.1 Evaluate and improve 

estimates of abundance, reproduction, survival, and growth for use in PVA models 

2 FY3-FY5 

and beyond 

NMFS, CDFG, NPS, CIMRI 

 

1.5.2 Develop population models 

to assess threats and identify key life history stages or demographic processes 

2 FY3-FY5 BBML, 

NMFS 

 45 45 

1.5.3 Conduct a PVA to 

determine time to extinction probabilities, trends to forecast the impact of threats, and the prospects for recovery 

2 FY3-FY5 MSU 45 45 

1.5.4 Expand PVAs to incorporate 

demographic and environmental stochasticity 

2 FY3-FY5 

and beyond 

BBML 45 45 

1.6 Maintain and enhance FY1-FY5 NMFS, INP See breakdown of costs below 
White Abalone Recovery Plan

 IMPLEMEN

V-5

IMPLEMENTATION SCHEDULE 

White Abalone (Haliotis sorenseni) 

Recovery Estimated Fiscal Year CosAction Number 

Action Description Priority 

Number

Action Duration 

Responsible Parties FY1 FY2 FY3 FY4 

communications with the Mexican government 

and beyond 

1.6.1 Establish a technical 

advisory team through the INP and invite them to participate in workshops and meetings 

2 FY1-FY5 

and beyond 

 

1.6.2 Participate in international 

conferences 

2 FY1-FY5 

and beyond 

5 5 6 6 

1.6.3 Collaborate with Mexico to 

help improve our understanding of the status of extant subpopulations throughout the range and to help conserve and protect them 

2 FY1-FY5 

and beyond 

 

1.7 Development of Post-Delisting 

Monitoring Plan 

3 Beyond 

FY1-FY5 

NMFS, INP, CDFG 

 

TOTALS FOR RECOVERY ACTION 1 305 450 587 588 2.1 Identify existing and potential 

habitat using multibeam sonar 

1 FY1-FY5 NMFS 
White Abalone Recovery Plan

 IMPLEMEN

V-6

IMPLEMENTATION SCHEDULE 

White Abalone (Haliotis sorenseni) 

Recovery Estimated Fiscal Year CosAction Number 

Action Description Priority 

Number

Action Duration 

Responsible Parties FY1 FY2 FY3 FY4 

generated bathymetry data and quantify and revise estimates of habitat availability in California 

2.2 Generate ROV transect data to 

assess biological and physical attributes of habitat 

1 FY1-FY5 

and beyond 

NMFS 

2.3 Determine the level of risk 

associated with habitat degradation/destruction that existing and potential viable populations (will) face 

2 FY1-FY5 

and beyond 

NMFS, CDFG 

2.4 Collaborate with Mexican 

researchers in assessing and monitoring white abalone habitat in Mexico 

2 FY1-FY5 

and beyond 

NMFS 

TOTALS FOR RECOVERY ACTION 2 0 0 0 0 3.1 Enforce State of California 

protections 

2 FY1-FY5 

and beyond 

CDFG 

3.2 Enforce Federal ESA 

protections 

1 FY1-FY5 

and beyond 

NMFS 
White Abalone Recovery Plan

 IMPLEMEN

V-7

IMPLEMENTATION SCHEDULE 

White Abalone (Haliotis sorenseni) 

Recovery Estimated Fiscal Year CosAction Number 

Action Description Priority 

Number

Action Duration 

Responsible Parties FY1 FY2 FY3 FY4 

3.3 Protect white abalone 

populations and habitat as they are discovered or established through enhancement 

 FY1-FY5 

and beyond 

See breakdown of costs below 

3.3.1 Continue state and federal 

review of permitted activities to minimize impacts in the wild 

1 FY1-FY5 

and beyond 

3.3.2 Evaluate current 

conservation measures (e.g., fishing restrictions, conservation areas, etc.) to afford viable wild populations appropriate protection from habitat destruction and illegal take 

 FY1-FY5 

and beyond 

3.3.2.1 Support establishment of 

Marine Protected Areas in the northern Channel Islands 

2 FY1-FY5 

and beyond 

3.3.2.2 Support maintenance of 

rockfish conservation areas 

2 FY1-FY5 

and beyond 

3.3.2.3 Uphold objectives of the 

CDFG Abalone Recovery Management 

2 FY1-FY5 

and beyond 

NMFS, CDFG, NPS, CINMS 
White Abalone Recovery Plan

 IMPLEMEN

V-8

IMPLEMENTATION SCHEDULE 

White Abalone (Haliotis sorenseni) 

Recovery Estimated Fiscal Year CosAction Number 

Action Description Priority 

Number

Action Duration 

Responsible Parties FY1 FY2 FY3 FY4 

Plan 

3.3.3 Establish an interagency 

(state/federal) enforcement task force that can monitor areas containing viable populations on a semiregular basis 

1 FY1-FY5 

and beyond 

NMFS, CDFG 10 10 15 15 

3.4 Enhance degraded habitat 

through restoration or mollifying anthropogenic impacts through mitigation, as necessary 

3 Beyond 

FY1-FY5 

NMFS 

TOTALS FOR RECOVERY ACTION 3 10 10 15 15 4.1 Identify factors that may reduce 

the risk of mortality associated with the removal, handling and transport of wild white abalone to rearing facilities 

1 FY1-FY3 NMFS, 

CIMRI, UW 

20 20 20 

4.2 Determine the number of 

rearing facilities and broodstock animals needed to meet the goals of NMFS global management plans 

1 FY1-FY5 NMFS, CDFG 

4.3 Establish a standard for security 

measures at facilities housing broodstock and captive-reared animals 

1 FY1-FY3 NMFS, 

CIMRI 

5 5 5 
White Abalone Recovery Plan

 IMPLEMEN

V-9

IMPLEMENTATION SCHEDULE 

White Abalone (Haliotis sorenseni) 

Recovery Estimated Fiscal Year CosAction Number 

Action Description Priority 

Number

Action Duration 

Responsible Parties FY1 FY2 FY3 FY4 

4.4 Comply with and periodically 

update NMFS global management plans for a captive propagations and enhancement program 

 FY1-FY5 

and beyond 

NMFS, UCSD, CIMRI, UW, BBML, CDFG, NPS 

See breakdown of costs below 

4.4.1 Comply with updated 

genetics management plan 

1 FY1-FY5 NMFS, 

UCSD, CIMRI 

 

4.4.2 Comply with updated 

disease management plan 

1 FY1-FY5 

and beyond 

NMFS, CIMRI, UW, BBML 

43 43 43 43 

4.4.3 Comply with updated 

management plan for the disposition of excess white abalone 

2 FY1-FY5 

and beyond 

NMFS, CDFG, NPS, CIMRI, CINMS, BBML, LBAOP, CA, SBMNH 

180 180 180 180 

4.4.4 Comply with updated field 

planting management plan 

1 FY1-FY5 

and beyond 

NMFS, CDFG, NPS, CINMS, CIMRI 

50 50 50 50 

4.5 Encourage partnerships with 

potential permit applicants who 

2 FY1-FY5 NMFS, 

LBAOP 

15 15 15 15 
White Abalone Recovery Plan

 IMPLEMEN

V-10

IMPLEMENTATION SCHEDULE 

White Abalone (Haliotis sorenseni) 

Recovery Estimated Fiscal Year CosAction Number 

Action Description Priority 

Number

Action Duration 

Responsible Parties FY1 FY2 FY3 FY4 

may be interested in participating in furthering the goals of the captive propagation program 

4.6 Enhance wild populations by 

outplanting captive-bred white abalone in selected sites throughout the range of the species 

1 FY1-FY5 

and beyond 

NMFS, CIMRI, CDFG, NPS, CINMS 

 

TOTALS FOR RECOVERY ACTION 4 463 468 473 453 5.1 Reduce likelihood of poaching 

by raising public awareness through outreach to regional fisheries management councils, industry groups, dive clubs/shops, and public media 

2 FY1-FY5 

and beyond 

NMFS, CDFG, LBAOP, CA, SBNHM 

 

5.2 Develop educational displays 

and materials by cooperating with NGOs, aquaria, secondary schools, and universities 

2 FY1-FY5 

and beyond 

NMFS, CDFG, LBAOP, CA, SBNHM 

 

5.3 Establish relationships with 

volunteer-based programs that can take part in various aspects of the captive propagation program (e.g., maintenance at 

3 FY1-FY5 

and beyond 

NMFS, LBAOP, CA, SBNHM 

10 10 10 10 
White Abalone Recovery Plan

 IMPLEMEN

V-11

IMPLEMENTATION SCHEDULE 

White Abalone (Haliotis sorenseni) 

Recovery Estimated Fiscal Year CosAction Number 

Action Description Priority 

Number

Action Duration 

Responsible Parties FY1 FY2 FY3 FY4 

hatcheries, research assistance, monitoring of captive-reared animals placed in the field etc.) 

TOTALS FOR RECOVERY ACTION 5 10 10 10 10 6.1 Seek out and apply for federal 

and private grants 

1 FY1-FY5 

and beyond 

NMFS, CDFG, NPS, CINMS, UW, BBML, UW, CIMRI, UCSD, MSU, LBAOP, CA, SBNHM 

 

6.2 Form cooperative funding 

agreements among state, federal and private entities 

1 FY1-FY5 

and beyond 

NMFS, CDFG, NPS, CINMS, UW, BBML, UW, CIMRI, UCSD, MSU, LBAOP, CA, SBNHM 

 

TOTALS FOR RECOVERY ACTION 6 0 0 0 0 TOTAL FOR IMPLEMENTATION DURING THE FIRST FIVE YEARS 788 938 1085 1066 

White Abalone Recovery Plan 

 LITERATURE CITED 

VI-1

VI. LITERATURE CITED 

Allee, W. C. 1931. Animal Aggregations. A Study in General Sociology. University of Chicago Press, Chicago. 

Altstatt, J. M., R. F. Ambrose, J. M. Engle, P. L. Haaker, K. D. Lafferty, and P. T. Raimondi. 1996. Recent declines 

of black abalone Haliotis cracherodii on the mainland coast of central California. Marine Ecology Progress 

Series 142:185-192. 

Babcock, R., and J. Keesing. 1999. Fertilization biology of the abalone Haliotis laevigata: Laboratory and field 

studies. Canadian Journal of Fisheries and Aquatic Sciences 56:1668-1678. 

Bakun, A. 2006. Wasp-waist populations and marine ecosystem dynamics: Navigating the ‘‘predator pit’’ 

topographies. Progress in Oceanography 68 (2006): 271–288. 

Bartsch, P. 1940. The West American Haliotis. Proceedings of the United States National Museum 89:49-58. 

Behrens, M. D., and K. D. Lafferty. 2005. Size frequency measures of white abalone, implication for conservation. 

Institute for Wildlife Studies, Ventura, CA. 

Benton, T. G., and A. Grant. 1999. Elasticity analysis as an important tool in evolutionary and population ecology. 

Trends in Ecology and Evolution 14(12): 467-471. 

Breen, P. A., and B. E. Adkins. 1980. Spawning in a British Columbia population of northern abalone, Haliotis 

kamtschatkana. The Veliger 23:177-179. 

Burge, R., S. Schultz, and M. Odemar. 1975. Draft report on recent abalone research in California with 

recommendations for management. . California Department of Fish and Game. 

Bushing, W. W. 1994. Biogeographic and ecological implications of kelp rafting as a dispersal vector for marine 

invertebrates. In Halverson, W. and G. Maender (eds.) Proceedings of the Fourth California Islands 

Symposium: Update on the Status of Resources, March 22-25, 1994. Santa Barbara Museum of Natural 

History (Santa Barbara, CA). pp. 103-110. 

Butler, J., M. Neuman, D. Pinkard, R. Kvitek, and G. R. Cochrane. 2006. The use of multibeam sonar mapping 

techniques to refine population estimates of the endangered white abalone (Haliotis sorenseni). Fishery 

Bulletin 104:521-532. 

Butler, J. L., and J. R. Hunter. 2002. White Abalone Restoration, Workshop Report 

California Department of Fish and Game. 2005. Abalone Recovery and Management Plan. Sacramento, California 

- The Resources Agency. 

Caswell, H. 2000. Prospective and retrospective perturbation analysis: Their roles in conservation biology. Ecology 

81:619-627. 

Caswell, W., S. Brault, A. J. Read, and T. D. Smith. 1998. Harpor porpoise and fisheries: An uncertainty analysis of 

incidental mortality. Ecological Applications 8:1226-1238. 

Chambers, M. D., H. Hurn, C. S. Friedman, and G. R. VanBlaricom. 2005. Drift card simulation of larval dispersal 

from San Nicolas Island, California, during black abalone spawning season. Pages 421-434 in D. K. 

Garcelon and C. A. Schwemm, editors. Proceedings of the Sixth California Islands Symposium, December 

1-3, 2003, Ventura, CA. National Park Service Technical Publication CHIS-05-01, Institute for Wildlife 

Studies, Arcata, CA. 

Chambers, M. D., G. R. VanBlaricom, L. Hauser, F. Utter, and C. S. Friedman. 2006. Genetic structure of black 

abalone (Haliotis cracherodii) populations in the California islands and central California coast: Impacts of 

larval dispersal and decimation from withering syndrome. Journal of Experimental Marine Biology and 

Ecology 331:173-185. 

Clavier, J. 1992. Fecundity and optimal sperm density for fertilization in the ormer (Haliotis tuberculata L.). Pages 

86-92 in S. A. Shepherd, M. J. Tegner, and S. A. Guzmán del Próo, editors. Abalone of the world: Biology, 

fisheries, and culture. Proceedings of the 1st International Symposium on Abalone. Blackwell Scientific 

Publications Ltd., Oxford, U.K. 

Cooper, J., M. Wieland, and A. Hines. 1977. Subtidal abalone populations in an area inhabited by sea otters. The 

Veliger 20:163-167. 

Cox, K. W. 1960. Review of the abalone of California. California Department of Fish and Game, Marine Resources 

Operations. 
White Abalone Recovery Plan 

 LITERATURE CITED 

VI-2

Cox, K. W. 1962. California abalones, family haliotidae. California Department of Fish and Game, Fish Bulletin 

118:1-132. 

Crofts, D. R. 1929. Haliotis. Pages 174 in Liverpool Marine Biology Committee Memoirs XXIX. University Press 

of Liverpool. 

Croker, R. S. 1931. Abalones. Division of Fish and Game, Fish Bulletin 30:58-72. 

Crouse, D. T., L. B. Crowder, and H. Caswell. 1987. A stage-based population model for loggerhead sea turtles and 

implications for conservation. Ecology 68:1412-1423. 

Crowder, L. B., D. T. Crouse, S. S. Heppell, and T. H. Martin. 1994. Predicting the impact of turtle excluder devices 

on loggerhead sea-turtle populations. Ecological Applications 4:437-445. 

Daniels, R., and R. Floren. 1998. Poaching pressures on northern California's abalone fishery. Journal of Shellfish 

Research 17:859-862. 

Davis, G. E., P. L. Haaker, and D. V. Richards. 1996. Status and trends of white abalone at the California Channel 

Islands. Transactions of the American Fisheries Society 125:42-48. 

Davis, G. E., P. L. Haaker, and D. V. Richards. 1998. The perilous condition of white abalone, Haliotis sorenseni, 

Bartsch, 1940. Journal of Shellfish Research 17:871-875. 

Dixon, C. D., R. W. Day, S. M. Huchette, and S. A. Shepherd. 2006. Successful seeding of hatchery-produced 

juvenile greenlip abalone to restore wild stocks. Fisheries Research 78:179-185. 

Estes, J. A., and G. R. VanBlaricom. 1985. Sea otters and shellfisheries. Pages 187-235 in R. Beverton, J. 

Beddington, and D. Lavigne, editors. Conflicts between marine mammals and fisheries. George, Allen, and 

Unwin, London, U.K. 

Friedman, C. S., K. B. Andree, K. A. Beauchamp, J. D. Moore, T. T. Robbins, J. D. Shields, and R. P. Hedrick. 

2000. 'Candidatus Xenohaliotis californiensis', a newly described pathogen of abalone, Haliotis spp., along 

the west coast of North America. International Journal of Systematic and Evolutionary Microbiology 

50:847-855. 

Friedman, C. S., M. Thomson, C. Chun, P. L. Haaker, and R. P. Hedrick. 1997. Withering syndrome of the black 

abalone, Haliotis cracherodii (Leach): water temperature, food availability, and parasites as possible 

causes. Journal of Shellfish Research 16:403-411. 

Geiger, D. L. 1999. Distribution and biogeography of the recent Haliotidae (Gastropoda: Vetigastropoda) 

worldwide. Boll. Malacologico 35:57-120. 

Gerber, L. R., and S. S. Heppell. 2004. The use of demographic sensitivity analysis in marine species conservation 

planning. Biological Conservation 120:121-128. 

Gotshall, D. W. 1977. Stomach contents of northern California dungeness crabs, Cancer magister. California Fish 

and Game. 

Gruenthal, K. M., and R. S. Burton. 2005. Genetic diversity and species identification in the endangered white 

abalone (Haliotis sorenseni). Conservation Genetics 6:929-939. 

Guzman del Proo, S. A. 1992. A review of the biology of abalone and its fishery in Mexico. Pages 341-359 in Case 

studies of abalone fisheries. 

Haaker, P. L. 1994. Assessment of abalone resources at the Channel Islands. The Fourth California Islands 

Symposium. 

Haaker, P. L., D. O. Parker, H. Togstad, D. V. Richards, G. E. Davis, and C. S. Friedman. 1992. Mass mortality and 

withering syndrome in black abalone, Haliotis cracherodii, in California. Pages 608 in S. A. Shepherd, M. 

J. Tegner, and S. A. Guzmán del Próo, editors. Abalone of the world: Biology, fisheries, and culture. 

Proceedings of the 1st International Symposium on Abalone. Blackwell Scientific Publications Ltd., 

Oxford, U.K. 

Hamm, D. E., and R. S. Burton. 2000. Population genetics of black abalone, Haliotis cracherodii, along the central 

California coast. Journal of Experimental Marine Biology and Ecology 254:235-247. 

Hayward, T. L. 1997. Pacific ocean climate change: atmospheric forcing, ocean circulation and ecosystem response. 

Trends in Ecology & Evolution 12:150-154. 

Hedrick, P. W., V. K. Rashbrook, and D. Hedgecock. 2000. Effective population size of winter-run chinook salmon 

based on microsatellite analysis of returning spawners. Can. J. Fish. Aquat. Sci. 57:2368-2373. 

Heppell, S. S., H. Caswell, and L. B. Crowder. 2000. Life histories and elasticity patterns: Perturbation analysis for 

species with minimal demographic data. Ecology 81:654-665. 
White Abalone Recovery Plan 

 LITERATURE CITED 

VI-3

Hines, A. H., and J. S. Pearse. 1982. Abalones, Shells, and Sea Otters - Dynamics of Prey Populations in Central 

California. Ecology 63:1547-1560. 

Hobday, A. J., and M. J. Tegner. 2000. Status review of white abalone (Haliotis sorenseni) throughout its range in 

California and Mexico. NOAA Technical Memorandum NOAA-TM-SWR-035, U.S. Department of 

Commerce, National Oceanic and Atmospheric Administration. National Marine Fisheries Service, Long 

Beach, CA, USA. 

Hobday, A. J., M. J. Tegner, and P. L. Haaker. 2001. Over-exploitation of a broadcast spawning marine invertebrate: 

Decline of the white abalone. Reviews in Fish Biology and Fisheries 10:493-514. 

Holling, C. S. 1959. Some characteristics of simple types of predation and parasitism. Canadian Entomologist 

91:385-398. 

Howorth, P. C. 1978. The abalone book. Naturegraph Publishers, Inc., Happy Camp, CA. 

Ino, T. 1952. Biological studies on the propagation of Japanese abalone (genus Haliotis). Bull. Tokai Reg. Fish. Res. 

Lab. 5:1-102. 

James, D. 2005. Abalone enhancement on artificial reefs in Port Phillip Bay, Victoria. Deakin University, Victoria. 

Karpov, K. A., P. L. Haaker, I. K. Taniguchi, and L. Rogers-Bennett. 2000. Serial depletion and the collapse of the 

California abalone fishery. Pages 11-24 in A. Campbell, editor. Workshop on rebuilding abalone stocks in 

British Columbia. Canadian Special Publications, Fish and Aquatic Sciences. 

Kojima, H. 1995. Evaluation of abalone stock enhancement through the release of hatchery-reared seeds. Marine 

and Freshwater Research 46:689-695. 

Lafferty, K. D., M. D. Behrens, G. E. Davis, P. L. Haaker, D. J. Kushner, D. V. Richards, I. K. Taniguchi, and M. J. 

Tegner. 2004. Habitat of endangered white abalone, Haliotis sorenseni. Biological Conservation 116:191-

194. 

Lee, Y. C., H. H. Kuo, and Y. G. Chen. 2002. Discrimination and abundance estimation of wild and released 

abalone Haliotis diversicolor using stable carbon and oxygen isotope analysis in north-eastern Taiwan. 

Fisheries Science 68:1020-1028. 

Leighton, D. L. 1966. Studies of food preference in algivorous invertebrates of Southern California kelp beds. 

Pacific Science 20:104. 

Leighton, D. L. 1972. Laboratory Observations on Early Growth of Abalone, Haliotis-Sorenseni, and Effect of 

Temperature on Larval Development and Settling Success. Fishery Bulletin of the National Oceanic and 

Atmospheric Administration 70:373-381. 

Leighton, D. L. 1974. The influence of temperature on larval and juvenile growth in three species of southern 

California abalones. Fishery Bulletin 72:1137-1145. 

Leighton, D. L. 1977. Some problems and advances in culture of North American abalones (Haliotis). in Proc. First 

Symp. Latin Amer. Aquaculture Assoc. , Maracay, Venezuela. 

Leighton, D. L. 2000. The Biology and Culture of the California Abalones. Dorrance Publishing Co., Pittsburg, PA. 

Leighton, D. L., and C. A. Lewis. 1982. Experimental hybridization in abalones. International Journal of 

Invertebrate Reproduction 5:273-282. 

Levitan, D. R. 1991. Influence of body size and population density on fertilization success and reproductive output 

in a free-spawning invertebrate. The Biological Bulletin 181:261-268. 

Lowry, L. F., and J. S. Pearse. 1973. Abalones and Sea-Urchins in an Area Inhabited by Sea Otters. Marine Biology 

23:213-219. 

Lundy, A. 1997. The California abalone industry - A pictorial history. Best Publishing Company, Flagstaff, Arizona. 

McCormick, T. B., K. Herbinson, T. S. Mill, and J. Altick. 1994. A Review of Abalone Seeding, Possible 

Significance and a New Seeding Device. Bulletin of Marine Science 55:680-693. 

McCormick, T. B., L. M. Buckley, J. Brogan, and L. M. Perry. 2008. Drift macroalgae as a potential dispersal 

mechanisms for the white abalone Haliotis sorenseni. Marine Ecology Progress Series 362: 225-232. 

McGinnity, P., P. Prodohl, A. Ferguson, R. Hynes, N. O Maoileidigh, N. Baker, D. Cotter, B. O'Hea, D. Cooke, G. 

Rogan, J. Taggart, and T. Cross. 2003. Fitness reduction and potential extinction of wild populations of 

Atlantic salmon, Salmo salar, as a result of interactions with escaped farm salmon. Proc. Roy. Soc. Lond. 

B. 
White Abalone Recovery Plan 

 LITERATURE CITED 

VI-4

McShane, P. E., K. P. Black, and M. G. Smith. 1988. Recruitment processes in Haliotis rubra (Mollusca: 

Gastropoda) and regional hydrodynamics in southeastern Australia imply localized dispersal of larvae. 

Journal of Experimental Marine Biology and Ecology 124:175-203. 

Moore, J. D., T. T. Robbins, and C. S. Friedman. 2000. Withering syndrome in farmed red abalone Haliotis 

rufescens: Thermal induction and association with a gastrointestinal Rickettsiales-like prokaryote. Journal 

of Aquatic Animal Health 12:26-34. 

Morris, R. F. 1963. The dynamics of epidemic spruce budworm populations. Mem. Entomol. Soc. Can. 

Morris, W. F., and D. F. Doak. 2004. Buffering of life histories against environmental stochasticity: Accounting for 

a spurious correlation between the variabilities of vital rates and their contributions to fitness. American 

Naturalist 163:579-590. 

Morse, D. E., and A. N. C. Morse. 1988. Chemical signals and molecular mechanisms- Learning from larvae. 

Oceanus 31. 

Newman, G. G. 1968. Growth of South African abalone Haliotis midae. Investigational Report Republic of South 

Africa Department of Industries, Division of Sea Fisheries. 

NOAA. 2001. Endangered and threatened species: endangered status for white abalone. 66 Federal Register 29046-

29055. 

O’Connell, C. 1955. The life history of the cabezon Scorpaenichthys marmoratus (Ayres). California Department of 

Fish and Game. Fish Bulletin 93. 76 pp. 

Owen, B., J. H. McLean, and R. J. Meyer. 1971. Hybridization in the eastern Pacific abalone (Haliotis). Bulletin of 

the Los Angeles County Museum of Natural History Science 9:1-37. 

Pennington, J. T. 1985. The ecology of fertilization of echinoid eggs: the consequences of sperm dilution, adult 

aggregation, and synchronous spawning. Biological Bulletin (Woods Hole) 169:417-430. 

Pikitch, E. K., C. Santora, E. A. Babcock, A. Bakun, R. Bonfil, D. O. Conover, P. Dayton, P. Doukakis, D. Fluharty, 

B. Heneman, E. D. Houde, J. Link, P. A. Livingston, M. Mangel, M. K. McAllister, J. Pope, and K. J. 

Sainsbury. 2004. Ecosystem based fishery management. Science 305:346-347. 

Prince, J. D., T. L. Sellers, W. B. Ford, and S. R. Talbot. 1987. Experimental evidence for limited dispersal of 

haliotid larvae (genus: Haliotis: Gastropoda: Gastropoda). Journal of Experimental Marine Biology and 

Ecology 106:243-263. 

Ramade-Villanueva, M. R., D. B. Lluch-Cota, S. E. Lluch-Cota, S. Hernandez- Vazquez, A. Espinoza-Montes, and 

A. Vega-Velazquez. 1998. An evaluation of the annual quota mechanism as a management tool in Mexican 

abalone fishery. Journal of Shellfish Research 17:847-851. 

Rogers-Bennett, L. 2007. Is climate change contributing to range reductions and localized extinctions in northern 

(Haliotis kamtschatkana) and flat (Haliotis walallensis) abalones? Bulletin of Marine Science 81:283-296. 

Rogers-Bennett, L., P. L. Haaker, T. O. Huff, and P. K. Dayton. 2002. Estimating baseline abundances of abalone in 

California for restoration. CalCOFI Reports 43:97-111. 

Rogers-Bennett, L., and J. S. Pearse. 1998. Experimental seeding of hatchery-reared juvenile red abalone in 

Northern California. Journal of Shellfish Research 17:877-880. 

Saether, B. E., and O. Bakke. 2000. Avian life history variation and contribution of demographic traits to the 

population growth rate. Ecology 81:642-653. 

Schiel, D. R. 1993. Experimental evaluation of commercial-scale enhancement of abalone Haliotis iris populations 

in New Zealand. Marine Ecology Progress Series 97:167-181. 

Seki, T., and K. Taniguchi. 2000. Rehabilitation of northern Japanese abalone, Haliotis discus hannai, populations 

by transplanting juveniles. Pages 72-83 in A. Campbell, editor. Workshop on rebuilding abalone stocks in 

British Columbia. Canadian Special Publication of Fisheries and Aquatic Sciences. 

Shepherd, S. A. 2000. Review on enhancement of abalone in Australia. Can. Spec. Publ. Fish. Aquat. Sci. 130:84-

97. 

Shepherd, S. A., and P. A. Breen. 1992. Mortality of abalone: Its estimation, variability, and causes. Pages 276-304 

in S. A. Shepherd, M. J. Tegner, and S. A. Guzmán del Próo, editors. Abalone of the world: Biology, 

fisheries, and culture. Blackwell Scientific Publications Ltd., Oxford, U.K. 

Shepherd, S. A., and L. D. Browne. 1993. What is an abalone stock: Implications for the role of refugia in 

conservation. Canadian Journal of Fish and Aquatic Sciences 50:2001-2009. 
White Abalone Recovery Plan 

 LITERATURE CITED 

VI-5

Shepherd, S. A., D. Lowe, and D. Partington. 1992. Studies on southern Australian abalone (Genus Haliotis): Larval 

dispersal and recruitment. Journal of Experimental Marine Biology and Ecology 164:247-260. 

Shepherd, S. A., J. M. Turrubiates Morales, and K. Hall. 1998. Decline of the abalone fishery at La Natividad, 

Mexico: overfishing or climate change? . Journal of Shellfish Research 17:839-846. 

Tegner, M. J. 1989. Chapter 17: The California abalone fishery: Production, ecological interactions, and prospects 

for the future. Pages 401-420 in J. F. Caddy, editor. Marine invertebrate fisheries: Their assessment and 

management. J. Wiley and Sons, New York. 

Tegner, M. J. 1993. Southern California Abalones - Can Stocks Be Rebuilt Using Marine Harvest Refugia. Canadian 

Journal of Fisheries and Aquatic Sciences 50:2010-2018. 

Tegner, M. J., L. V. Basch, and P. K. Dayton. 1996. Near extinction of an exploited marine invertebrate. Trends in 

Ecology & Evolution 11:278-280. 

Tegner, M. J., and R. A. Butler. 1985. Drift-tube study of the dispersal potential of green abalone (Haliotis fulgens) 

in the Southern California Bight: Implications for recovery of depleted populations. Marine Ecology 

Progress Series 26:73-84. 

Tegner, M. J., and P. K. Dayton. 1987. El Niño effects on southern California kelp forest communities. Advances in 

Ecological Research 17:243-279. 

Tegner, M. J., P. L. Haaker, K. L. Riser, and L. I. Vilchis. 2001. Climate variability, kelp forests, and the southern 

California red abalone fishery. Journal of Shellfish Research 20:755-763. 

Thompson, B., J. Dixon, S. Shoeter, and D. J. Reish. 1993. Benthic Invertebrates. U. Calif. Press, Berkely, CA. 

Tutschulte, T. C. 1976. The comparative ecology of three sympatric abalone. University of California, San Diego. 

Tutschulte, T. C., and J. H. Connell. 1981. Reproductive biology of three species of Abalones (Haliotis) in Southern 

California. The Veliger 23:195-206. 

VanBlaricom, G. R. 1993. Dynamics and distribution of black abalone populations at San Nicolas Island, California. 

Pages 323-334 in F. G. Hochberg, editor. Third California Islands Symposium: recent advances in research 

on the California Islands. Santa Barbara Museum of Natural History, Santa Barbara, CA. 

Wells, F. E., and J. K. Keesing. 1990. Population characteristics of the abalone Haliotis roei on intertidal platforms 

in the Perth metropolitan area. Journal of the Australian Malacological Society 11:65-71. 

White Abalone Recovery Plan 

 APPENDIX A 

A-1

APPENDIX A. 

WHITE ABALONE BROODSTOCK COLLECTION AND HOLDING PROTOCOL

As recommended by Thomas B. McCormick, Channel Islands Marine Resource Institute and Dr. 

Carolyn Friedman, School of Aquatic and Fishery Sciences, University of Washington 

Seven species of abalone are found in rocky habitat in coastal waters of California. Five of these 

species, the red, pink, green, black, and white, have been the subject of commercial and sport 

take for the last 150 years. Over-exploitation has led to the demise of abalone stocks not only in 

California but around the world. Stocks of the white abalone (Haliotis sorenseni) have fallen so 

low that it has been listed as the first endangered marine invertebrate in the U. S. 

 

Efforts have begun to establish a hatchery breeding program that will produce the next 

generation of broodstock for outplanting in the wild. The first step in this program involves the 

collection of wild animals to will serve as breeding stock. This document provides information 

on the collection, shipment, and holding of white abalone. The intent is to minimize stress and 

maximize survival during this process. 

White Abalone Habitat:The deepest living California abalone, white abalone were historically 

reported to occur at depths of 5 to 60 meters and are currently most abundant at 30 to 60 meters 

(Cox , 1960). Shallow populations were more easily removed by fishing pressure during the 

1970’s leaving remnants of the population at mean depths of 48 meters (Haaker et al., 2000). 

Diving to and retrieving abalone from these depths presents a formidable challenge. White 

abalone are found on rocky habitat, on low relief rock or boulders at the sand interface 

(Tutschlute, 1976; Davis et al., 1996). 

Collection of Abalone: Once abalone have been located great care must be taken to avoid 

cutting the soft parts of this marine gastropod during removal from the substrate. Removal of 

any wild abalone intact from its rocky substrate is always a challenge. Like all other abalone 

species, white abalone move about and adhere to the rock substrate with their large muscular 

foot. When disturbed the abalone will use its foot to pull the shell down tightly against the rock 

substrate for protection. Once in this defensive position it is very difficult to remove the abalone 

without injuring it. 

Traditionally abalone taken for commercial, sport, aquaculture, and research activities have been 

removed form the substrate with an abalone iron. The iron consists of a thin metal blade 1 – 2” 

across and 1/8 – 1⁄4” thick that is inserted between the substrate and the foot of the abalone. A 

swift upward motion of iron’s handle is used to remove the animal from the substrate. In the 

hands of an experienced diver, the abalone iron is a quick and efficient tool for obtaining 

abalone. One disadvantage of this method is that the rocky substrate on which the abalone is 

perched may be uneven and the abalone iron may nick or cut the foot. Burge et al. (1975) found 
White Abalone Recovery Plan 

 APPENDIX A 

A-2

that commercial fisherman cut 12.6% of the pink abalone that they collected. Sports divers 

deeply cut 38% of the abalone in their bag limits. 

Abalone often succumb to wounds suffered during removal from the substrate. Abalone blood 

has no clotting ability (Cox, 1962) and relatively minor cuts can cause loss of haemolymph, 

resulting in mortality. Burge et al. (1975) showed that mortality in sub-legal red abalone from 

half-inch cuts was 60% in the laboratory. 

To minimize stress and trauma to the animals during collection and transport, the following 

methods are suggested. 

Underwater – Removing abalone from substrate: 

When collecting abalone there are several options for removing animals alive and in good 

condition from submerged rocky outcrops as follows: 

Kelp “bait”: Wave a frond of kelp directly in front of the abalone. If the abalone has not 

been previously disturbed, the smell or touch of the kelp will cause the abalone to raise 

its shell and extend the front of its foot in a feeding posture. While in this position, the 

abalone can be easily removed from the substrate by swiftly inserting a hand under the 

foot and pulling upward, removing it from the rock. 

Predator “Scare”: To avoid predation by the sunflower star (Pycnopodia helianthoides) 

abalone may attempt to outrun this highly mobile sea star. Although the sunflower star is 

not as abundant in southern California as it is to the north, it may be possible to obtain a 

sea star and place it directly in front of the abalone. This should cause the abalone to 

make an evasive move. When the abalone is actively moving across the substrate it can 

be easily removed with a rapid motion. 

Use of Anesthetics: Anesthetics can be utilized to make abalone relax their grip on the 

substrate. Several anesthetics have been shown to be effective for abalone. For collection 

activities, anesthetics have two disadvantages: first, at colder temperatures (12-16°C) 

anesthetics are slow acting. The solution containing the anesthetic must be in contact 

with the abalone for 5 – 25 minutes. At depths where abalone are found, setting up an 

apparatus to administer an anesthetic and then waiting for it to take effect will require 

later decompression stops for the divers. The second, disadvantage is that it will be 

necessary to develop a means of exposing the abalone to the anesthetic for an extended 

period. It may be possible to develop a plastic bag or other container that can be pressed 

against the substrate to form a tight seal around the abalone. The anesthetic could then be 

introduced into this containment. 

Two anesthetics that have been shown to be effective for abalone are Tricane 

Methanesulfonate (MS-222) and (Ethyl-paraminobenzoate (EPAP). Neither of these 

chemicals is approved by the FDA for use in food animals, however, this is not an issue 
White Abalone Recovery Plan 

 APPENDIX A 

A-3

for white abalone. A saturated solution of carbon dioxide (CO2) is almost as effective at 

loosening abalone from the substrate. Like the anesthetics, long exposure times are 

needed. Carbon dioxide is considered a low-regulator drug by the FDA. 

Abalone iron: This is the traditional way to remove abalone from the rock substrate. In 

order to minimize cuts and trauma the collector should follow the following guidelines: 

Approach: Abalone are sensitive to water motion and changes in light. 

Approach an abalone slowly and do not cast a shadow so that the abalone does 

not go into a defensive posture. 

Point of insertion for the Abalone Iron: Injury to the head and anterior portion 

of the foot should be avoided. The abalone iron should be inserted along the sides 

or back of the shell. Look for an area of rock that is smooth and free of crevices 

so that the iron does not cut into the foot where it has 

Handling of the abalone iron: When the diver is in position, hold the iron with 

the concave side down. Press the tip of the iron against the rock substrate and 

slide quickly forward into a gap between the shell and the substrate. Still pressing 

downward, slide the iron 2-4” under the shell. Quickly pull upward on the handle 

end of the iron to pop the abalone off the substrate. This entire motion should be 

done quickly. The element of surprise is essential. If the iron is inserted too 

slowly the abalone will clamp down, and in the resulting struggle the abalone will 

invariably sustain damage to the foot. 

When not to use the iron: When the abalone is in a normal resting posture the 

shell of the abalone will be raised 0.25 – 0.5” above the rocky substrate with the 

epipode protruding from beneath the shell. The soft epipode is black and white 

with the distal ends fringed, much like that of a pink abalone. Small tentacles 

protrude from the epipode and provide the abalone with a sense of touch. When 

the abalone is disturbed, the epipode will be withdrawn and the shell pulled down 

against the rock. In this position, it is almost impossible to pry the abalone off the 

rock without injury. It is better to wait 10 – 20 minutes for the abalone to resume 

a normal resting posture before trying a removal attempt. 

Following Removal – Use of an Artificial Substrate: Once the abalone has been 

removed from the rock it will be transferred to a holding tank or ice chest at the surface 

and then transferred again to the holding facility. The number of times that an abalone is 

removed from the substrate can be minimized if an artificial substrate is provided. A thin 

piece of plastic, such as the top to a 1 to 5-gallon bucket, can act as portable substrate for 

the abalone. Once the abalone is removed from the ocean floor it can be placed directly 

on the plastic. The abalone can stay on the plastic in the holding tank and ice chest. 
White Abalone Recovery Plan 

 APPENDIX A 

A-4

Seawater Temperature: The temperature of the seawater where the abalone are 

collected should be noted (in advance if possible) so that the temperature of the holding 

tank on board ship can be brought as close as possible to this temperature, plus or minus 

2°C. 

Transport to surface: Avoid thermal shock on the trip to the surface by placing each 

abalone in a sealed plastic bag filled with seawater. A 1-Gallon Zip-Lock bag works 

well. Caution: Do not keep the abalone in the bag for more than 15 - 20 minutes as the 

animal will consume all available oxygen. 

Holding Facilities on Board Vessel: There are several options for holding abalone on board a 

vessel, depending upon the length of the cruise, the amount of deck space, availability of flowing 

seawater and electricity. Temperature control is essential. Surveys or seawater temperatures in 

white abalone habitat at 20 m depths off Santa Catalina Island range indicate that yearly 

temperatures range from 13 to 18°C (Tsuchulte and Connell, 1981). Temperatures of the 

holding tanks should be kept within two degrees of those at the collection site. 

Different options for holding abalone on board ship are: 

1) Ice chest with gel packs: for holding times of up to 24 hours. This is the simplest and 

least expensive holding and transport system. Both juvenile and adult abalone from 

farms are routinely transported in this manner. The principal is to keep the animals cool 

and moist. Frozen gel packs are used for cooling but should never come into direct 

contact with the abalone. Individual gel packs should be wrapped with newspaper in 

order to avoid extremely low temperatures followed by thawing of the gel. To wrap each 

gel pack, start with 6 – 8 sheets of newspaper. Fold the newspaper lengthwise so that it is 

one inch longer than the gel pack. Wrap the newspaper around the gel pack so that the 

two ends are open. Fasten the newspaper in place with packing tape. To insure that only 

the ends of the gel pack provide cooling keep the newspaper dry. Used in this manner the 

gel pack will last 24 to 30 hours. The ratio of abalone weight to gel pack weight should 

be 2.5:1, that is, 2.5 pounds of abalone for every one pound of frozen gel pack (wrapped 

in newspaper). Gel packs should be placed on the bottom of the ice chest standing on 

edge against the walls of the ice chest. A large plastic bag (13 gallon or more) should be 

placed in the ice chest. Slightly moistened absorbent material, such as foam rubber or 

paper towels, should be placed in the bottom of the plastic bag to absorb excess water 

from the abalone. If available, a layer of kelp on top of the absorbent will give the 

abalone something to adhere to and provide moisture. For short transport times (8 – 12 

hours) leave the bag open at the top to allow air into the bag. For transport times in 

excess of 12 hours the bags should be filled with oxygen and sealed. Components 

required are: Ice chest, gel-ice packs, plastic bags, foam rubber, and paper towels. It may 

also be necessary to purchase or rent an oxygen tank and regulator. 
White Abalone Recovery Plan 

 APPENDIX A 

A-5

2) Self-Cooling Ice Chest: For short holding times a self-cooling portable ice chest may be 

suitable to transport abalone. This system eliminates the need for frozen gel packs. 

Caution should be taken to determine the chilling capacity of the ice chest in advance of 

any collection activities. Packing of the abalone is similar to that outlined in 1), above. 

System components should include: Self-cooling Ice Chest: These recreational coolers 

require a 12 VDC power source, converter for ship board 24 VDC power, plastic bags, 

foam rubber, and paper towels. 

3) Place abalone in boat’s live well. For multi-day trips during periods when surface 

seawater temperatures are less than 17°C, and close to that of where the animals were 

collected, place abalone in the boat’s live holding tanks. Make sure that water circulation 

is maintained constantly. Shipboard seawater pumping systems often use brass or bronze 

pumps or plumbing. The copper in these metals is toxic to abalone and an alternative 

water supply should be used. 

4) Flowing seawater tank with chiller: For multi-day collection trips it will be necessary to 

keep the abalone at temperatures close to those of the collection site. A small plastic, 

stainless steel, or titanium pump can be used to obtain water from any depth when 

coupled to a flexible 1” intake pipe hung overboard. If surface water is used, an 

appropriately sized chiller with a titanium heat exchanger can be used to maintain the 

desired water temperature. Holding system components should include: Seawater pump, 

titanium chiller, insulated holding tank with top, miscellaneous PVC plumbing, small air 

pump and airstones, and a maximum / minimum thermometer. 

5) Flowing seawater from depth - This system is similar to the one above but has no chiller. 

The end of a flexible intake hose is lowered to a depth of 20 – 50 m to reach the desired 

water temperature. The disadvantage of this system is that cool water can not be pumped 

in while underway. If there is a long trip to port during the summer, temperatures can be 

controlled with frozen gel packs. Components are the same as above except for the 

chiller. 

Tagging, Data Acquisition, and Tissue Sampling: 

Tags: It essential to tag abalone immediately upon bringing on board ship. The longest 

lasting tag is made of a stainless steel washer (approximately 5/8” in diameter) that has 

been stamped with an identifying number (Haaker et al., 1986). The tag is held in place 

with stainless steel wire by passing the wire through the top-most respiratory pores and 

through the tag. The wires are then twisted together so that the wire is tight against the 

shell and does not move. Trim the excess wire and bend the end against the shell so there 

is no sharp projection. 

Data Acquisition: Once the abalone have been tagged the shell length, total weight, and 

sex should be recorded. The data sheet should also note the GPS location of site, depth, 
White Abalone Recovery Plan 

 APPENDIX A 

A-6

bottom temperature, bottom type, types of kelp observed, the person who collected the 

abalone and any other relevant details. 

Tissue Sampling: Tissue samples will provide valuable genetic information about the 

population structure of the white abalone. It will also be useful to track lineage in 

hatchery raised stocks. A non-lethal tissue sampling methodology has been developed 

that uses one of the abalone’s many epipodal tentacles. While this sampling method 

poses minimal risk to the abalone, it should only be carried out by someone skilled in 

handling abalone. The method is as follows: With a pair of tweezers grasp the end of 

one of the epipodal tentacles on the sides or posterior of the animal. While gently pulling 

the tentacle taught use a nail clipper to cut the tentacle 1 – 2 mm from its base. Place the 

tentacle in a microfuge tube with 1-2 ml of a high salt buffer 5XNET, pH 8 solution. 

Seal the top of the tube and record the animal number, location, and date on the tube 

label. Refrigerate the tube. This buffer will preserve the DNA in the sample indefinitely. 

Materials: 100 ml Buffered 5XNET, pH 8 solution, composed of 2.5 Molar NaCl, 0.25 

Molar EDTA, 0.25 Tris pH 8. Also 4 Plastic containers with tops 50 ml., 10 plastic 

droppers, and 50 microfuge tubes. 

Transport to Holding Facilities: 

Recommended transport times: When properly packed, abalone can be shipped without 

water for 24 hours with 100% survival. Shipping times for wild caught white abalone 

should be kept to only a few hours to minimize stress. 

Packaging: Careful attention should be given to packing the animals for transport. 

Packing procedure – Prior to handling the animal, prepare the shipping bag. Immerse 

three pieces of foam rubber sheet (18” X 18”, or appropriate size to fit the plastic bag) 

into the cold seawater of the holding tank. Squeeze the excess water from two pieces of 

foam then place them in a plastic bag (2’ X 2’6”, 13 gallons or larger). Remove abalone 

from the temporary holding tank and drain excess water for 30 seconds. Place the 

abalone foot down on the two layers of foam. Several abalone can be placed side by side 

on the foam. Place the third piece of damp foam over the abalone. For trips shorter than 

12 hours, no supplemental oxygen is required. Loosely close the plastic bag with a 

rubber band so that a small amount of gas exchange can occur. Oxygen may be added for 

trips greater than 8 hours. To fill the bag with oxygen, gather the open end and insert the 

tube from the oxygen regulator into the bag while holding the bag shut around the tube. 

Fill the bag with oxygen then press all the oxygen out of the bag, and fill again. Seal the 

bag by twisting it, making a small loop and securing the loop with a strong rubber band to 

prevent the escape of any gas. Once the abalone are sealed into the plastic bags, they 

should be placed in a Styrofoam box or ice chest. Place the abalone in a single layer in 

the container. Cooling is provided by frozen gel packs. The quantity and handling of gel 

packs is the same as that described for holding facilities onboard vessel – ice chest with 

gel packs. 
White Abalone Recovery Plan 

 APPENDIX A 

A-7

Holding Facilities: 

 

Health and Gonad Examination: Upon arrival of the abalone at the holding facility the 

health and spawning condition of the abalone should be assessed. The soft tissues of the 

foot and epipode should be examined for any nicks, cuts or abrasions resulting from 

collection. Any findings should be noted on a data sheet that contains the abalone 

number, and the date and location of collection. The total weight and shell length should 

be noted along with information about the appearance of the shell. For example, if the 

growing edge of the shell is sharp, this indicates that the animal has recently grown. If 

the edge is rounded, it indicates that some time has past since the shell grew. The extent 

of fouling of the shell should be noted. 

The gonad index (GI) of each abalone should be noted. Several methods have been 

developed to measure gonad ripeness. Uki and Kikuchi (1982) developed a convenient 

scale as follows: 

 Gonad Ranking Description of Gonad and Spawning Activity 

0 No gonad observed. Not possible to determine sex. Abalone will 

not spawn. 

1 Small volume of gonad observed. Possible to determine sex of 

abalone by gonad color. Males have a light tan or creamy colored 

gonad; females have a darker gonad from brown to green in color. 

Abalone will not spawn. 

2 Larger volume of gonad. Easy to distinguish sexes. Gonad bulk 

visible. Abalone may spawn. 

3 Volume of gonad quite large, may extend below the lower plane of 

the shell. Abalone will probably spawn. 

After abalone are placed in the holding systems, the gonad index should be checked no 

more often than once a month since the process of removing the abalone from the tank 

and handling it is stressful and will inhibit growth. 

Quarantine: Newly acquired abalone should be held separately from those already in the 

facility for a period of three to six weeks. This will provide enough time for the new 

abalone to undergo an antibiotic treatment for withering syndrome. During the 

quarantine period, all equipment should be washed with 100 ppm chlorine and rinsed 

with seawater after use in the new abalone tanks. Note: Technicians should observe good 

husbandry practice and wash hands in freshwater before and after working in each tank. 
White Abalone Recovery Plan 

 APPENDIX A 

A-8

Withering Syndrome Inoculation Protocol: Dr. Carolyn Friedman, pathologist at the 

University of Washington has developed an antibiotic treatment for the control of a 

rickettsiales-like-protozoan or RLP (Gardner et al., 1995) that causes withering 

syndrome in white abalone. Oxytetracycline is an effective treatment when nine 

injections are administered over a five-week period. Oxytetracycline can also be 

incorporated in the feed at up to 6.0 g active oxytetracycline per 100 pounds body weight 

per day for 14 days to control withering syndrome. 

If abalone appear to be shrunken they will be will be inoculated as per Dr. Friedman’s 

protocol (carolynF@U.Washington.edu). Treatments should be effective for 6 – 12 

months, particularly if influent water is UV sterilized. Withering syndrome now appears 

to be endemic throughout southern California. 

Waxing Protocol: The calcium carbonate shells of abalone are a perfect substrate for 

boring organisms such as clams, (Pholadidea conradi), sponges (Cliona spp.) and the 

mud worm (Polydora spp.). These organisms may weaken the shell and cause irritation 

as the abalone repairs the inside of the shell. It is possible to eliminate many of these 

invaders without harming the abalone. Only heavily infested animals should be treated, 

since some stress is associated with this procedure. 

A method of sealing the outer shell with wax was developed by Trevelyan et al. (1994) as 

a means of combating exotic sabellid polychaetes in commercial farms. Warm liquid 

wax is brushed onto the shell of the abalone, completely covering the openings of the 

invaders. The wax is allowed to harden then the abalone is returned to its tank. The 

infesting organisms, now sealed under the wax will die in a day or so. 

The technique consists of four steps: Anesthesia, shell drying, wax coating, and 

incubation as follows: 

Anesthesia: See notes on anesthesia in the Handling section below. 

Shell Drying: It is important to have the shell dry in order for the wax mixture to 

adhere to it. After the abalone have been removed from the side of the tank, scrub 

the shell with a stiff brush to remove silt and fouling organisms. Rinse the shell 

in seawater. Place the animal on a material from which it can easily be removed, 

by laying shade cloth, netting or cloth in a water table and introducing a trickle of 

seawater. The seawater will keep the foot moist. Use a dry towel to remove 

excess moisture from the shell. A fan run at moderate speed can be used to 

accelerate the drying process. 

Wax coating: A mixture of three ingredients is used in order to reduce the 

working temperature of the liquid phase an increase the flexibility of the hardened 

solid wax. The type and amount of the ingredients are: 
White Abalone Recovery Plan 

 APPENDIX A 

A-9

 

 Paraffin 55% 

 Petrolatum (petroleum jelly) 35% 

 Bees Wax 10% 

The ingredients can be easily be melted in a microwave oven by placing them in a 

small plastic container of the type that yogurt or cottage cheese comes in. Place 

the small container in a larger container. Pour water into the larger container until 

it is half full. Both containers are then placed in the microwave oven and heated 

until all the wax is melted. The heated water in the large container will help to 

melt the wax and keep it warm when coating the abalone. NOTE: Always heat 

the wax in a water bath. Never place only the wax mixture in the microwave as 

this may result in a fire. 

Once the wax is melted and the abalone shell appears dry, apply the liquid wax 

with a 2 – 3” wide brush. The respiratory pores can be covered in wax without a 

deleterious effect on the animal. Once applied the wax cools quickly and will not 

burn the tissue of the abalone or the technician. After being waxed the abalone 

can be immediately returned to its holding tank. 

Incubation: After being returned to the holding tank the wax coating is allowed 

to incubate for 3 – 7 days. During this time the shell under the wax turns 

anaerobic, killing the biofouling organisms. Following incubation, the shells are 

vigorously aerated and sprayed to remove the wax coating. A black anaerobic 

layer on the outside of the shell can be observed. This layer quickly disappears. 

 

Holding Conditions: Conditions under which white abalone are held should mimic day 

to day and seasonal variations in the natural habitat. Consideration should be given to 

control temperature, dissolved oxygen, feeding, waste removal, bacteria, lighting 

conditions, and handling methods. 

Temperature: As noted above, the annual range of seawater temperatures at 20 

m off southern California range from 10°C - 18°C. The desired range for holding 

is 14°C - 17°C. Temperatures as low as 10°C may be used to stimulate gonad 

maturation. The effect of temperature on the occurrence of withering syndrome 

must be considered. In red abalone, withering syndrome is exacerbated or even 

induced in rickettsiaeles injected animals when held at water temperatures greater 

than 15 °C. Prior to holding abalone a temperatures of 16°C - 17°C, animals 

should be treated with antibiotics as in the Withering Syndrome Inoculation 

Protocol, described previously. 
White Abalone Recovery Plan 

 APPENDIX A 

A-10

Dissolved Oxygen: Dissolved oxygen should be at or within 10% of saturation. 

Aeration can be used to both provide oxygen and water movement within the 

holding tank. 

Feeding: The types of feed used, the frequency of feeding, amount of feed 

consumed, and treatment of the kelp should be considered as follows: 

Feed Types: The dietary preferences of white abalone broodstock are not clearly 

understood. Laminaria and Macrocystis probably make up a large portion of the 

diet. The reddish brown color of the shell indicates that white abalone also 

consume some type of red algae throughout their life. 

Frequency of feeding: The frequency of feeding should be once or twice a week 

depending upon the rate of consumption and condition of the kelp. 

Quantity of Feed: Abalone are not aggressive feeders and should be fed ad 

libitum. It is important to measure the quantity of feed consumed to get a feeling 

for the health of the abalone. One of the first signs of withering syndrome is loss 

of appetite. 

Kelp treatment: Prior to feeding to abalone, kelp should be immersed for 5 

minutes in freshwater. This will remove unwanted epibionts and may also reduce 

the introduction of pathogenic bacteria, such as rickettsia. 

Water Flow: Flowing water provides aeration while removing solid and 

dissolved waste products. Water should be provided to the holding tank at a rate 

of 10% of tank volume per hour per kilogram of abalone weight. 

Waste Removal: A byproduct of protein metabolism, the ammonium ion (NH3-

N), is extremely toxic to abalone. An adequate supply of flowing seawater should 

be used to remove ammonia from the holding tanks. Solid waste should be 

prevented from accumulating on the tank bottom since this it can quickly turn 

anaerobic and produce toxic ammonia compounds. A self-cleaning tank is 

optimal. This can be achieved by using a small pump to recirculate water within 

the tank. If the holding tank is not self-cleaning waste should be removed with a 

siphon daily. 

Bacteria: Pathogenic bacteria, such as rickettsiae may enter the abalone holding 

system in the water flow. To reduce the number of bacteria in the culture system 

water should be filtered and passed through an ultra violet (UV) sterilizer. A 

minimum dosage of 15,000 μW sec/cm2 should be applied. 
White Abalone Recovery Plan 

 APPENDIX A 

A-11

Lighting Conditions: Lighting levels at the 20 – 50 m depths where white 

abalone are found are much lower than at the surface. Low wattage bulbs of 40 

watts or less should be used to illuminate in the holding tanks. To induce gonad 

maturation lights should be placed on a timer to simulate the change of seasons. 

Handling Methods: Abalone must be handled with great care since their 

tenacious hold on the substrate and tender flesh make a combination that may 

result in nicks or cuts in the hands of an unpracticed worker. To reduce the 

possibility of wounding an abalone, only people skilled in the handling of abalone 

should move the abalone. If abalone are held in plastic or fiberglass tanks a thin 

metal or plastic kitchen spatula can be an effective tool to quickly remove abalone 

from a tank. If a spatula is used it should be inserted from the rear or sides of the 

animal. Never insert a spatula under the head. Should abalone prove difficult to 

move anesthetics should be used as follows: 

Anesthesia: To reduce the chances of cutting abalone when they handled 

for gonad inspection, measurement or spawning, it is advisable to 

anesthetize them first. Several anesthetists are available: 

Carbon Dioxide (CO2): Seawater saturated with carbon dioxide makes a 

suitable anesthetic for abalone. To produce a saturated carbon dioxide 

solution, bubble carbon dioxide through seawater for 15 minutes. 

Pressurized CO2 is supplied from a cylinder via a regulator, tube and 6” – 

10”airstone. It is best if the saturated solution can be made in a separate 

tank. Once the solution is saturated, drain the normal seawater from the 

white abalone holding tank and pour in the saturated seawater. The 

abalone should loose its grip in 4 – 5 minutes. Immersion in the CO2

saturated seawater should be limited to 10 minutes otherwise suffocation 

may result. After the abalone have been removed from the tank, place 

them in normal seawater to revive them. Discard the saturated water and 

refill the holding tank with seawater. NOTE: Although CO2 is a low 

regulatory drug, it is not currently FDA approved for abalone.

Ethyl-para-amino-benzonate (Epab) has been used as an effective 

anesthetic for abalone. Efficacy of this drug is dependent upon water 

temperature and dosage. At 15 °C, a dosage of 30 ppm for 15 minutes is 

effective. Longer times are required at colder temperatures. Do not 

exceed a 30-minute exposure. A related chemical compound, Tricane 

Methanesulfonate, marketed as MS-222 is also an effective anesthetant for 

abalone. The dosage of MS-222 should be twice that of Epab. NOTE: 

Neither Epab nor MS-222 are FDA approved for farmed abalone. 
White Abalone Recovery Plan 

 APPENDIX A 

A-12

Tools: To remove abalone from the substrate, a plastic kitchen spatula is 

effective. Look for a wide blade and thin profile. To prevent the 

possibility of cutting or nicking the abalone, sand down the front of the 

spatula. 

Acknowledgement 

Peter Haaker, and Ian Taniguchi of the California Department of Fish and Game as well as Neil 

Hooker of University of California, Santa Barbara provided valuable contributions to this 

document. Questions or Comments, contact: Tom McCormick 805 798-2505 email: 

T_McCormick@ojai.net. 

References 

Burge, R., S. Schultz, M. Odemar. 1975. Draft report on recent abalone research in California 

with recommendations for management. Dept. of Fish and Game. 

Cox, K.W. 1960. Review of the abalone of California. Calif. Fish & Game Bull. 46:381-406. 

Davis, G.E., P.L. Haaker and D.V. Richards. 1996. Status and trends of white abalone at the 

California Channel Islands. Trans. Am. Fish. Soc. 125(1), 42-48. 

Haaker, P.L., D.V. Richards, and I. Taniguchi. 2000. White abalone program. October 9 – 25, 

1999 Cruise Report. CSFG, 330 Golden Shore, Suite 50, Long Beach, CA 90802. 

Haaker, P.L., D.O. Parker, and K.C. Henderson. 1986. Red abalone size data from Johnsons 

Lee, Santa Rosa Island, collected from 1978 to 1984. Calif. Dept. Fish. Game, Mar. Res. Tech. 

Rep. No. 53, 56 pp. 

Trevelyan, G.A., R.C.Fields, P.F.Arthur, and F. Oaks, 1994. The use of wax to control shell 

parasites of red abalone, Haliotis rufescens. Report to the California abalone industry. 6 pp. 

Tsuchulte, T. 1976. The comparative ecology of three sympatric abalones. Ph.D. dissertation. 

University of California, San Diego, Calif. 

Tutschulte, T.C. and J.H. Connell. 1981. Reproduction biology of three species of abalones 

(Haliotis) in southern California. Veliger 3:195 – 206. 

Uki, N. and S. Kikuchi, 1982. Influence of food levels on maturation and spawning of the 

abalone. VII. Comparative examinations of rearing apparatus for conditioning of adult abalone. 

Bull. Tohoku Reg. Fish. Res. Lab., No. 45:45-53. 
White Abalone Recovery Plan 

 APPENDIX B 

B-1

APPENDIX B. 

NATIONAL MARINE FISHERIES SERVICE WHITE ABALONE GENETICS MANAGEMENT PLAN 

Ex situ conservation of white abalone requires a genetics management plan to ensure the longterm conservation of the species. Healthy species normally contain much genetic diversity, both 

within local breeding populations and between them (National Research Council 1996). Genetic 

diversity represents the basis for adaptive evolution. Loss of this diversity, through extirpation 

of local populations, fragmentation of previously inter-connected populations, and careless 

selection of breeding stock for hatcheries, represents a serious threat to long-term species 

survival (National Research Council 1996). 

This Genetics Management Plan is designed to reduce the following risks: 1) loss of withinpopulation variability; 2) loss of among-population variability; 3) genetic adaptation to hatchery 

conditions; and 4) extinction. Loss of genetic variability within cultured populations will be 

avoided by using a large broodstock size (approximately 100 individuals), and by maximizing 

the numbers of different males and females participating during each spawning attempt. If 

genetically distinct populations are identified from field sampling, aquaculture regimes will 

maintain population-specific stocks. Subsequent field planting activities will be designed to 

ensure that juveniles are returned to appropriate locations depending on their parentage. To 

prevent genetic adaptation to hatchery conditions, approximately equal numbers of offspring 

from all pair crosses will be maintained through at least the first year of life, the period when 

most mortality is experienced. Although the separate culture of many different broods is 

somewhat inefficient, it is required to prevent a lab-adapted strain from outcompeting broods 

which may, in fact, be better adapted to natural conditions. These measures will serve to reduce 

the risks of inbreeding depression, genetic drift, artificial selection, and extinction (National 

Research Council 1996). 

Given that white abalone are in an extremely perilous state, with densities below those required 

for successful reproduction, a team of abalone biologists recommended in November 2001 that 

broodstock for a captive breeding program be collected immediately. The consensus was to 

obtain the broodstock by taking all abalone encountered in groups of five or less animals. They 

advised taking all isolated individuals, and taking all animals in any group of less than 30 

animals within 10 m2

, up to the quota (approximately 100 broodstock among all hatcheries 

combined). 

Our lack of understanding of white abalone population genetics makes us unable, at this time, to 

outline the mating protocol in detail. Studies with black abalone, an intertidal species, suggest 

significant genetic differences among populations from different areas throughout the species 

range (Hamm and Burton 2000), but red abalone, a coastal species, are believed to be panmictic, 

with low levels of genetic differentiation among populations across the species range (Burton 

and Tegner 2000). As broodstock are collected during 2003, tissue samples will be taken from 
White Abalone Recovery Plan 

 APPENDIX B 

B-2

white abalone epipodia as has been done with the 11 animals currently in captivity. 

Methodologies for collection and preparation of the tissue samples are provided in Hamm and 

Burton (2000) and Burton and Tegner (2000). Protein electrophoresis, microsatellite analyses, 

and mitochondrial DNA sequencing will help to provide a better understanding of white abalone 

population genetic stock structure by 2004, prior to implementation of any field planting 

program. Initial investigations (18 white abalone tissue samples on-hand from pre-listing 

collections) have revealed three mtDNA haplotypes (based on 512 bp of the COI gene), and 5 

alleles at each of three microsatellite loci (from those developed for pinto abalone by Miller et al. 

2001). 

If no distinct genetic differences among broodstock collected from different locations are 

identified, white abalone will be induced to spawn using the methods described by Morse et al. 

(1978) and McCormick (2000) multiple times a year. Single pair (one male and one female) 

crosses will be performed so that the genetic histories of F1 generations are known and every 

attempt will be made to use different adults during each spawning attempt. Each cross could 

produce a maximum of approximately 100,000 juveniles based on the first spawning attempt 

conducted by McCormick and UCSB in 2001. Optimal grow-out densities and size ranges of F1 

generation individuals, based on growth rates and survivorship, will be determined (this 

information is currently being recorded by McCormick). Based on these determinations, a 

portion of the progeny will be held in the hatchery until the time of field planting and others 

could be used in a variety of ways (e.g., stocked in the ocean, transferred to other hatcheries, 

laboratory studies; see White Abalone Disposition of Excess Individuals Plan). 

If distinct genetic wild populations are identified and great enough numbers of broodstock are 

collected, we will modify our general plan to attempt to maintain this structure in the hatcheries. 

This will be accomplished by following the same procedures as outlined above except that 

crosses will be performed between broodstock from the same wild population in order to produce 

population-specific juveniles. 

Genetic research and tools may also prove valuable for the development of a genetic marker for 

monitoring the growth and survival of captive-bred white abalone that are field planted at sizes 

too small (< 10 mm) for traditional tagging methods to be used. Dr. Ron Burton, geneticist at 

Scripps Institution of Oceanography believes that with a sufficient number of nuclear and 

mitochondrial genetic markers, it may be possible to distinguish broodstock and their offspring 

from wild abalone. Such an approach might be based on identification of rare mitochondrial 

DNA haplotypes in females and uncommon microsatellite DNA alleles. Ideally, broodstock with 

distinct genetic markers would be pre-selected for breeding so that offspring genotypes would be 

extremely uncommon in natural populations. It remains uncertain whether enough broodstock 

will be collected to afford the program this luxury. 

References

Burton, R.S. and Tegner, M.J. 2000. Enhancement of red abalone Haliotis rufescens stocks at 

San Miguel Island: reassessing a success story. Marine Ecology Progress Series 202: 303-308. 
White Abalone Recovery Plan 

 APPENDIX B 

B-3

Hamm, D.E., and Burton, R.S. 2000. Population genetics of black abalone, Haliotis cracherodii, 

along the central California coast. Marine Ecology Progress Series 202: 303-308. 

McCormick, T.B. 2000. Abalone (Haliotis spp.) aquaculture: present status and a stock 

assessment tool. In Workshop on Rebuilding Abalone Stocks in British Columbia. Edited by A. 

Campbell. Canadian Special Publication Journal of Fisheries and Aquatic Sciences 130:55-60. 

Miller, K.M., Laberee, K., Kaukinen, K.H., Li, S., Withler R.E. 2001. Development of 

microsatellite loci in pinto abalone (Haliotis kamtschatkana). Molecular Ecology Notes. 1:315-

317. 

Morse, D.E., Hooker, N., and Morse, A. 1978. Chemical control of reproduction in bivalve and 

gastropod molluscs, III: an inexpensive technique for mariculture of many species. Proceedings 

of the World Maricultural Society 9: 543-547. 

National Research Council. 1996. Upstream: Salmon and Society in the Pacific Northwest. The 

National Academy of Sciences, Washington, D.C. 

White Abalone Recovery Plan 

 APPENDIX C 

C-1

APPENDIX C. 

NATIONAL MARINE FISHERIES SERVICE WHITE ABALONE DISEASE AND PARASITE MANAGEMENT 

PLAN

The purpose of this document is to outline protocols that all hatcheries engaged in the captive 

maintenance and/or propagation of white abalone must adhere to in order to prevent the spread 

of disease and parasites. These protocols may be expanded or altered in the future as knowledge 

is gained regarding captive propagation of white abalone and their susceptibility to disease and 

parasites in the hatchery and nature. 

Withering Syndrome Prevention and Treatment

It has been known since the 1990s that species closely related to white abalone (Halitois 

sorenseni), including black (H. cracherodii), red (H. rufescens) and green (H. fulgens) abalone, 

are adversely affected by a disease called withering syndrome (WS). The etiological agent was 

recently identified as an intracellular rickettsial bacterium (RLP) that was placed in a new taxon 

and has been given the provisional status of “Candidatus Xenohaliotis californiensis” (Friedman 

et al. 2000). In addition, temperature-induced stress (> 18 o

C) may render Haliotis spp. more 

susceptible to the disease (Moore et al. 2000). 

In September 2002 it was confirmed that white abalone are susceptible to the RLP that causes 

WS (T. McCormick and James Moore, pers. comm.). Because the RLP appears to occur in the 

water column throughout white abalone’s range and the possibility exists that the RLP could be 

introduced into the hatchery environment, even with stringent measures to treat incoming water 

(e.g. through food sources), measures must be taken to test broodstock and captive-bred white 

abalone for WS regularly. Dr. Carolyn Friedman, a pathologist at the University of Washington 

and member of the white abalone recovery team, suggests quarterly testing by feces polymerase 

chain reaction (PCR) and periodic lethal testing if deemed necessary. Given that the primary 

purpose of captive propagation for the endangered white abalone is to generate animals that will 

replenish the heavily depleted wild population (see NMFS White Abalone Field Planting Plan; 

Appendix E), the National Marine Fisheries Service (NOAA Fisheries) will, to the best of its 

abilities, ensure that: 1) preventative measures are taken by all hatcheries to reduce the likelihood 

of introducing WS into hatchery environments; and 2) animals placed into the wild are RLP-free 

and pose no risk to abalone in the wild. 

Preventative Measures: 

1) Technicians working with brood stock will receive training in good husbandry practice before 

and after working in each tank. 
White Abalone Recovery Plan 

 APPENDIX C 

C-2

2) Water flowing into tanks will be filtered (<5 μm for larvae and early juveniles, <60 μm for 

adults) and ultra violet irradiated (at least 15,000 μW sec/cm2

 for all life stages). These 

irradiation levels appear to be safe for larvae and very early stages (T. McCormick pers. comm.). 

3) Water quality (e.g., temperature, salinity, dissolved oxygen) will be tested on a daily basis. 

4) All new brood stock will be quarantined for a period of six weeks, tested for WS, and treated 

with injections if they are infected with the RLP (protocol outlined below). 

5) Equipment used in quarantine tanks will be rinsed in 100 ppm chlorine and rinsed well with 

freshwater and dried between uses. Ideally, each tank should have its own equipment. 

6) White abalone will be tested on a quarterly basis by feces PCR analysis for WS. Prior to field 

planting, a subset of animals (n = 300) should be held at higher temperatures (approx. 18 oC for 

at least 8 weeks) to increase the potential for detecting the presence of the WS bacterium. 

A minimum of 300 animals per production unit must be sacrificed for detection of the WS 

bacterium. If WS is detected in captive-bred animals, those animals will not be field planted 

until the animals are RLP-free. 

7) Kelp will be surface cleaned with freshwater and possibilities of artificially propagating of 

food will be explored. 

 

8) Testing animals for resistance to WS and selecting those for field planting may be explored. 

9) There will be limited and monitored access to hatcheries by authorized personnel only. 

10) Transfers between holding facilities may only occur if both facilities are demonstrated to be 

free of specific diseases and parasites 

Treatment of RLP-infected abalone: 

Prior to placing animals in the wild, captively propagated abalone must be proven to be free of 

the RLP. Work with this pathogen in other species, combined with preliminary data from white 

abalone, indicates that it should be possible to eliminate the RLP from captively reared white 

abalone. 

White abalone infected with the RLP must be treated with a proven, safe inoculation protocol 

that has been developed for closely related species (C. Friedman pers.comm.) to completely 

eliminate the pathogen. In red abalone oxytetracycline (OTC) injections can be 100 % effective 

in eradicating the RLP from infected abalone, depending on the animal’s level of infection prior 

to treatment (Friedman et al. 2003). The following procedures for OTC injection treatment of 

infected individuals will be followed prior to release (T. McCormick, pers. comm. and Friedman 

et al. 2003): 
White Abalone Recovery Plan 

 APPENDIX C 

C-3

--------------------------------------------------------------------------------------------------------------------- 

Antibiotic Treatment Protocol for the Control of Rickettsiales-Like-Prokaryotes in the Gastrointestinal 

Epithelia of Abalone: For Laboratory Use Only 

As recommended by Dr. Carolyn Friedman, Assistant Professor, School of Aquatic and Fishery 

Sciences, University of Washington, (206) 543-9519. 

Drug Preparation:

Drug: Liquamycin LA-200 (OTC), Oxytetracycline Injection, 200 mg/l concentrate (Pfizer), found at veterinary 

supply centers. 

Prepare prior to each use a 10 mg/l solution from the 200 mg/l stock (1:20) dilution in 2% saline using distilled 

water. No pH adjustment. 

Drug Calculation:

Previous experiments determined the need to achieve a 21 mg/kg dose of oxytetracycline in tissue weight (Friedman 

et al. 2003). Previous sampling of red abalone at the Bodega Bay Marine Laboratory has yielded a mean percent 

(%) tissue weight of approximately 54.85% for healthy black abalone and 67.47% for healthy red abalone. Percent 

tissue weight was determined by total weight minus shell weight, divided by total weight X 100. As proportional 

shell weight varies between species and with age, the % tissue weight to total weight (shell and tissues) needs to be 

determined prior to dosing, if possible. 

Example calculation for a 90 g red abalone: 

90 g x 0.6747 = 60.723 g tissue weight. 

60.723 g tissue weight = 0.060723 kg tissue weight. 

0.060723 kg x 21 mg/kg = 1.275 mg oxytetracycline needed for that animal to achieve a 21 mg/kg dose. 

Solve for a where; 

a (10 mg/ml) = 1.275 oxytetracycline 

a= 1.275 mg/10 mg/ml = 0.1275 ml or 127.5 ul for a 90g animal. 

Suggested Injection Regime:

Inoculations will be administered to incoming wild brood stock that have tested positive for withering syndrome to 

prevent the spread of the disease throughout the hatchery. Inoculations will be administered to captive-bred white 

abalone that have tested positive for withering syndrome prior to field planting to prevent the spread of the disease 

to healthy animals in the hatchery and in the wild. 

Using a sterile 1 ml, 27 G-1/2 syringe for each animal, withdraw the appropriate amount of diluted oxytetracycline. 

Remove any air bubbles and slowly inject the oxytetracycline into the pedal muscle of the abalone. Rotate injection 

sites for subsequent injections. Needle-depth insertion should be curbed somewhat for smaller animals. 

A total of 9-12 injections is necessary to eliminate or significantly reduce infections of the RLP, according to results 

from experiments performed at the Shellfish Health Laboratory at Bodega Bay Marine Lab (Friedman et al. 2003).

It is suggested that the first three injections are given on a Monday, Wednesday, and Friday followed by a two-week 

post-injection recovery period. Repeat this sequences again until 9-12 total injections have been administered.

------------------------------------------------------------------------------------------------------------------------------------------- 
White Abalone Recovery Plan 

 APPENDIX C 

C-4

Unfortunately, the injection treatment is time consuming, labor-intensive, expensive and 

invasive. Recently, the efficacy of an oral (per os) administration of OTC to control losses due 

to WS was tested with red and black abalone (Friedman et al. 2003). Abalone were fed to excess 

for 14 consecutive days with floating medicated, alginate-based feed made at the Abalone Farm, 

Inc. in Cayucos, CA. Survivorship, biomass, RLP intensity and degree of WS in abalone fed a 

medicated diet were compared to those fed kelp (Macrocystis pyrifera, as a control). A per os

delivery of OTC was effective in reducing the prevalence and intensity of infection of RLPs in 

abalone, however, some RLPs did survive the per os treatment. Despite the fact that this 

treatment did not completely eradicate the disease from infected individuals, bacterial burdens 

were substantially reduced for at least one year after a single (14-d) treatment regime (Friedman 

et al. 2003). This treatment could prove promising for white abalone and deserves future 

consideration given as it is not invasive, is less time consuming, less labor intensive, and less 

expensive than the injection treatment. 

The Friedman et al. (2003) paper also discusses possible risks associated with development of 

antibiotic resistance among animals that are administered drug treatments and remarks that these 

concerns warrant further study. Atlantic salmon that received a similar OTC therapy as that used 

in the Friedman et al. (2003) study showed no evidence for selection of antibiotic resistance in 

salmon digestive tract flora during a 28 d study (Kerry et al. 1997). 

Sabellid-worm Prevention and Treatment: 

Another potential threat to brood stock, cultured white abalone, and wild populations upon field 

planting of cultured animals, is an exotic polychaete worm (Terebrasabella heterouncinata) that 

inhabits the shells of abalone where it lives in tubes. The sabellid worm was introduced into 

California abalone farms during the mid- to late-1980's with imported South African abalone. 

The parasite causes shell deformities that weaken the shells of abalone, thereby reducing growth 

rates and production (Culver et al. 1995?, Leighton 2000). Since the introduction of this nonindigenous polychaete worm to aquaculture facilities, the state of California requires that any 

abalone to be planted in State waters must originate from a hatchery that has been certified as 

sabellid-free. The State will conduct regular inspections of all aquaculture facilities used in the 

recovery program to certify that they are, in fact, sabellid-free. Although these measures greatly 

reduce risks associated with the parasite, it remains remotely possible that wild white abalone 

have been exposed to this organism. Also, Polydora polychaetes, boring clams and sponges, and 

other epicommensal organisms may be present on wild animal shells and should be reduced or 

eliminated prior to removal from quarantine. In order to prevent introduction of the sabellid pest 

into unaffected facilities, as well as other epicommensal organisms known to have adverse 

affects on abalone (other polychaetes, mollusks, and sponges), a non-invasive procedure of 

applying a wax mixture to the shells may be performed on incoming broodstock that are heavily 

infested with boring organisms (Oakes et al. 1995) 

Preventative Measures: 
Draft White Abalone Recovery Plan 

 APPENDIX C 

C-5

In addition to the measures listed above for the prevention of WS, the following measures will be 

taken at all facilities in order to avoid the spread of sabellid parasites (T. McCormick pers. 

comm.; J. Butler pers. comm.). 

1) All new brood stock will be quarantined for a period of six weeks and visually examined for 

sabellid infestation. 

2) Perform shell waxing procedure on broodstock (McCormick and Friedman in prep.).

3) Hatcheries will adhere to State requirements on sabellid-testing. 

References

Friedman, C.S., Andree, K.B., Beauchamp, K.A., Moore, J.D., Robbins, T.T., Shields, J.D., and 

Hedrick, R.P. 2000. “Candidatus Xenohaliotis californiensis” a newly described pathogen of 

abalone, Haliotis spp., along the west coast of North America. Int. J. Syst. Evol. Microbiol.

50(2):847-855. 

Friedman, C.S., G. Trevelyan, T.T. Robbin, E.P. Mulder, and R. Fields. 2003. Development of 

an oral administration of oxytetracycline to control losses due to withering syndrome in cultured 

red abalone Haliotis rufescens. Aquacult. 

Kerry, J., NicGabhainn, S, and Smith, P. 1997. Changes in oxytetracycline resistance of 

intestinal microflora following oral administration of this agent to Atlantic salmon (Salmo salar

L.) smolts in a marine environment. Aquacult. 157(3-4):187-193. 

Leighton, D.L. 2000. The Biology and Culture of California Abalone. Dorrance Pub. Co. 

Pittsburgh, PA. 

Moore, J. D., T. T. Robbins, and C. S. Friedman. 2000. Withering syndrome in farmed red 

abalone Haliotis rufescens: Thermal induction and association with a gastrointestinal 

Rickettsiales-like prokaryote. J. Aquat. An. Health 12:26-34. 

White Abalone Recovery Plan 

 APPENDIX D 

D-1

APPENDIX D. 

NATIONAL MARINE FISHERIES SERVICE WHITE ABALONE PLAN FOR DISPOSITION OF EXCESS 

INDIVIDUALS

The intent of a captive breeding program is to produce larval and juvenile abalone which can be 

transferred to grow-out facilities for eventual field planting. Because white abalone produce 

millions of gametes during each spawning event, hatcheries will develop more progeny than they 

can safely and economically maintain. Disposing of excess individuals, typical in many hatchery 

settings, will be performed to: 1) enhance the growth rates of cultured individuals (by reducing 

negative density-dependent effects); 2) minimize maintenance costs of the hatchery, while 

maximizing survival; and 3) provide animals for experimental field and laboratory testing. 

Excess animals will be selected based on their size and will encompass the range of sizes that 

define each life stage (0.2-0.3 mm larvae; 0.3-2 mm postlarvae; 2-4 mm early juveniles; 5-25 

mm juveniles, Dave Leighton, pers. comm.). Thus, both the culled and retained animals will be 

comprised of slow- and fast-growing individuals and will mimic the size and presumably, 

genetic structure of the original population. 

Depending on funding and the production rates of white abalone at the culture facility, excess 

healthy animals (disease- and parasite-free) will be: 1) stocked in the ocean as postlarvae and 

juveniles (0.3-25 mm size range; see White Abalone Field planting Plan); 2) subjects in diet and 

density-dependent growth experiments, thermal tolerance experiments, predator/competitor 

response experiments, or genetic experiments (5-25 mm size range; see White Abalone Genetics 

Management Plan); 3) transferred to permit-approved laboratories at other institutions to answer 

other critical research questions (e.g., susceptibility to withering syndrome, habitat preferences); 

4) transferred to additional, permit-approved settlement and grow-out facilities; 5) transferred to 

permit-approved aquaria for educational/outreach purposes; or 6) destroyed. The possibility of 

storing white abalone gametes is an area that requires further investigation and the Protected 

Resources Division/Permitting Office of NOAA Fisheries will receive an addendum to this 

protocol, outlining details of the plan, before any action is pursued. 

Option 1 will test the effects of various habitat parameters (e.g., depth, distance to shore, 

temperature) and field planting size on the survival of juvenile white abalone. This option would 

require monitoring of experimental field plant sites to estimate survival and could involve public 

participation as an outreach effort. Option 1, in combination with the primary field planting 

program, would help to address a number of critical research questions including: 1) 

development of measurable standards for assessing recovery in white abalone, such as 

recruitment and survival rates and viable population and aggregation sizes; 2) investigation of 

habitat character effects on recruitment and survival of white abalone; and 3) investigation of the 

occurrence and magnitude of juvenile migration in white abalone using acoustic tags. 
White Abalone Recovery Plan 

 APPENDIX D 

D-2

Option 2 would address critical research topics in a laboratory setting: 1) investigation of the 

effects of temperature, diet and density on the survival and growth of larvae and juveniles; 2) 

investigation of how the intermittent exposure of cultured individuals to predator and competitor 

cues might affect the recruitment potential and survivability of individuals and; 3) development 

of appropriate genetic techniques for assessing population structure, and marking and identifying 

captive-bred individuals. 

Option 3 describes moving animals to permit-approved facilities, that have met the requirements 

set forth by the State and NOAA Fisheries, to address very specific research questions in the 

laboratory regarding the susceptibility of white abalone to withering syndrome, possible 

treatments for the disease, and controlled experiments that examine growth and survival of white 

abalone inhabiting a variety of habitat types. To develop a successful field planting program, it 

is critical that scientists investigate the effects of withering syndrome, a disease caused by a 

naturally-occurring Rickettsiales-like prokaryote (see Disease and Parasite Management Plan), 

on white abalone, and the effects of a variety of habitat parameters on the growth and survival of 

white abalone. The necessary expertise and equipment required to answer these questions will 

likely not be available at the hatcheries and therefore excess, test animals should be transferred to 

other facilities (e.g., the University of California Bodega Bay Marine Laboratory) where experts 

are well-equipped to conduct these investigations. 

Option 4 would involve transferring excess animals to additional permit-approved facilities to 

rear captive-bred animals until they reach sizes suitable for field planting. These facilities would 

have to meet the requirements set forth by the State and NOAA Fisheries prior to receiving 

animals. Spreading captive-bred animals among multiple rearing facilities would enhance 

growth and survival of white abalone by ameliorating economic pressures at any one facility, 

space limitations at any one facility, and the potential for losing all of the program’s animals due 

to a catastrophic event at any one facility. 

Option 5 would involve the transfer of excess white abalone to permit-approved 

educational/outreach facilities that would develop exhibits focusing on the biological and 

socioeconomic importance of abalone and their habitats to California and Baja California, 

Mexico. 

Option 6 would be invoked as a last resort if other methods of disposing of excess individuals are 

eliminated as viable options
White Abalone Recovery Plan 

 APPENDIX E 

E-1

APPENDIX E. 

NATIONAL MARINE FISHERIES SERVICE WHITE ABALONE FIELD PLANTING PLAN

A team of international experts in abalone biology and culture met at the Southwest Fisheries 

Science Center in La Jolla, California, from November 8-9, 2001 to discuss a rebuilding strategy 

for white abalone. The consensus of the group was that hatchery production and stocking of 

cultured white abalone was the preferred option for rebuilding the population despite mixed 

results reported from planting efforts for related species in California (Leighton 1985, Tegner 

and Butler 1985, Leighton 2000, McCormick 2000, Tegner 2000). Factors that affect stocking 

success are handling in transit, method of planting, size at release, stocking density, small scale 

structure of the natural substratum, and predation (Leighton 1989, McCormick et al. 1994, 

Preece et al. 1997, Saito 1979, Saito 1984, Kojima 1995, Rogers-Bennett and Pearse 1998). 

These factors are taken into account in the White Abalone Field Planting Plan outlined below. 

Summary

Stocking of white abalone raised in a hatchery will be conducted with three major goals 1) to 

enhance wild white abalone populations and 2) to learn more about the best ways to enhance the 

growth and survival of stocked white abalone and 3) to stock disease and parasite-free abalone. 

Stocking will be conducted as rigorous studies involving the release of young abalone from 

multiple life history stages; late-stage larvae, smaller juveniles, advanced juveniles and young 

adults (to 10 cm). Earlier research has shown survival of planted abalone increases with age and 

size at release (Saito 1984), but economics favor release of greater numbers of younger stages 

(Leighton 2000). Size-structured matrix models of white abalone show that increasing the 

numbers of larger juvenile abalone have more of an impact on population growth than increasing 

the numbers of smaller juveniles (Rogers-Bennett and Leaf 2006). Monitoring success of stocked 

abalone with different age and size groups will require surveys and sampling of both the exposed 

rock surfaces (most easily accomplished with ROV, day and nighttime observations) and the 

under rock environment, especially for postlarvae and early juveniles (by diving and turning 

rocks). Small boulders may be collected to assess the survival of late stage larvae. Adult white 

abalone are typically emergent, occupying exposed surfaces of bottom rock, while younger 

stages are cryptic. 

Recognition of the Aideal nursery habitat@, and therefore the locations seeding will most likely be 

successful in terms of growth and survival, will be important to the choice of preferred project 

sites. Knowledge of substrate and food requirements for early stages will be especially 

important for future efforts to enhance seeding success by habitat modification and optimization. 

Specific locations have been identified as superior recruitment environments from previous years 

for red abalone (e.g., southern Point Loma shelf; Leighton 1968) and for green abalone (e.g., 

south La Jolla shallow subtidal; Leighton 1985) and for white abalone (e.g. San Clemente Island) 

(Rogers-Bennett et al. 2002). However, much of the benthic terrain supporting adult white 
White Abalone Recovery Plan 

 APPENDIX E 

E-2

abalone populations today on offshore banks is mature established boulder and sand patch 

substrate with little micro-relief to provide shelter for postlarval and juvenile stages. In such 

areas it will be important to find small rock piles or reef outcrops which in their structure provide 

adequate protective shelter for young stages. As an important extension of the immediate 

program, efforts to improve juvenile white abalone habitat may be necessary. 

Success of stocking may be judged by, the discovery of live, healthy and growing young and the 

absence of empty shells in the area using appropriate sampling methods. Sampling procedures 

will in most cases involve turning of small flat rock (those having open space beneath). Where 

such elements of the substratum are lacking, crevices and cavities between rocks may be 

explored, but destructive habitat surveys will be avoided. Most ideal natural substratum consists 

of pieces of flat sedimentary rock, with minimal over-growth of algae and other organisms, 

situated over bed rock, but providing open beneath-rock space. 

Site Selection and Habitat Improvement

Success rates of abalone stocking programs have been mixed worldwide (Tegner and Butler 

1989, Schiel 1993, McCormick et al. 1994) and much of this variation has been attributed to sitespecific conditions. In Japan, large-scale stocking programs have been underway for years. In 

1979, more than 10 million juvenile abalone were produced and stocked by fishing cooperatives 

(Tegner and Butler 1989). Survival rates however in this program vary widely from 1-80% 

(Saito 1984, Tegner and Butler 1989, Kojima 1995). Similarly, in New Zealand survival of 

stocked juvenile abalone ranged from 1-72% (Schiel 1993). Much of this variability in stocking 

survival has been attributed to major differences between sites. Some sites yield good survival 

rates while others do not. More juvenile red abalone survived in stocking experiments in 

northern abalone at sites with red sea urchin spine canopy than sites without (Rogers-Bennett and 

Pearse 1998). This same result has been observed for juvenile abalone stocked in sites with sea 

urchins in South Africa (Mayfield ref). Small scale variation in micropredators in southern 

California sites have been reported and these small predators have been shown to consume large 

numbers of newly settled and juvenile red abalone in laboratory experiments (Svedlund, RogersBennett and Caselle, in prep). More research is needed to help identify key site variables critical 

for the survival of stocked juvenile white abalone. This white abalone recovery program is 

science-based and therefore designed to learn more about survival rates at various sites and the 

parameters which are linked to survival. 

White abalone habitats vary with location in terms of bottom topography, geologic structure and 

algal community composition. Typically islandic environments present a combination of larger 

rock outcrops with expanses of low relief bed rock and sand zones. Aside from the common 

encrusting and articulated coralline red algal species and occasional red algae (e.g., Rhodymenia 

spp.), attached brown algae include Laminaria farlowii, Agarum fimbriatum, and in shallower 

water, Pterygophora californica and Eisenia arborea. Macrocystis pyrifera is often present as 

bottom drift. Around Isla Natividad in Baja California, Mexico, white abalone have been 
White Abalone Recovery Plan 

 APPENDIX E 

E-3

observed on sheet rock at 12-27m with the following dominant algae: Eisenia arborea, 

Macrocystis pyrifera, Gelidium robustum, and calcareous algae (Turrubiates; pers. comm.). For 

mainland sites such as Point Loma, Pelagophycus porra, which attaches at a depth of 25-40 m, is 

a good indicator of potential white abalone habitat. Fronds of this alga may join drift of 

Macrocystis fragments to serve as food for deep-living abalone. The best indication of white 

abalone habitat is to find the animals themselves, or the knowledge that populations existed there 

within the past few decades. Fishery data has been used to identify areas that were once very 

productive for white abalone during the fishery. San Clemente Island produced the most white 

abalone per unit of suitable habitat (1.44mt/Ha.), Tanner and Cortez banks were the next most 

productive followed by Santa Barbara Island (Rogers-Bennett et al. 2002). Relevant information 

can also be gathered in the laboratory by subjecting excess, captive-bred animals to a variety of 

habitat types along with the associated food and monitoring their growth and survival under 

different conditions over time (see Disposition of Excess Individuals Plan). 

Preferred habitat is probably size- and age-specific and may also depend on the presence or 

absence of other species (Sweijd et al. 1998, De Waal and Cook 2001). The possibility exists 

that formerly preferred habitat for white abalone (juveniles and adults) has been altered in their 

absence, and may no longer be suitable for seeding. Community changes including cocompetitors (sea urchins), invasive species which may feed on abalone larvae (brittle stars), and 

substrate changes (e.g., overgrowth by articulated coralline algae, sponges and colonial 

tunicates) may require that extensive habitat restoration will be necessary to create appropriate 

features of the small-scale habitat for planting of cultured white abalone juveniles and larvae. 

Similar changes in habitat rendering it unsuitable have been documented once black abalone 

populations declined following mass mortalities due to disease (Miner et al. 2007). The use of 

metamorphic, talus rock at seeding sites not only would create suitable habitat, but also increase 

juvenile survival and permit easy sampling in monitoring procedures. 

Healthy, mid-size, white abalone broodstock will be collected from oceanic banks known 

through a recent ROV survey conducted during July 2002. While oceanic seamounts and banks 

may provide broodstock for the propagation program, initial seeding exercises will be most 

efficiently conducted in locations more accessible from the mainland and the Channel Islands. 

Depth range for the mainland sites would be 20-40 m and for islandic locations, 20-50+m. To 

ensure that genetic contamination of the wild population does not occur and to minimize risks 

associated with hybridization an objective of preliminary stocking will be to reintroduce white 

abalone into habitat that was previously occupied by the species, but that has undergone local 

extinction. This strategy will also aid in the ability of researchers to monitor the growth and 

survival of filed planted animals (see “Monitoring the Performance of a Field Planting Program” 

below). Additional permits will be sought if planting locations fall within National Marine 

Sanctuary boundaries. 

Environmental parameters to be examined at each site will include temperature distribution, 

substrate composition, bottom topography on a meso- and micro-scale, macro- and micro floral 
White Abalone Recovery Plan 

 APPENDIX E 

E-4

elements, predator populations and potential competitors. Environmental conditions at one site 

may be more appropriate for larval seeding (e.g., relatively smooth and barren rock with sparse 

algal turf, abundant microrelief and beneath-rock space, few sea stars, ophiuroids, and other 

predators), while another area may be better suited for stocking young adults (e.g., higher relief, 

boulder and sand patch bottom with common macroalgae, such as Laminaria farlowii). 

Lack of suitable larval recruitment habitat may be an important factor limiting abalone 

population growth. Both physical and biotic elements of the bottom in potential white abalone 

habitat may conspire to preclude successful settlement and metamorphosis of planktonic larvae. 

Juvenile survival may be restricted by inadequate crevice shelter, open foraging area, and 

predation. Certain ophiuroid and other filter-feeding species may capture larvae, while sea stars, 

amphipods, other benthic predators may seek out recently settled postlarvae or larger juveniles. 

A mature reef community typically supports an abundance of predators and competitors for 

space and food. Articulated coralline algae often form a continuous cover on exposed rock 

surfaces, while sponges, bivalves, crabs and other species occupy spaces between and beneath 

rocks. 

Abalone Recruitment Modules (ARMS) have been used to examine the success of stocked 

juveniles as well as the set of wild juveniles. Installing ARMs provides uniform substrates with 

known surface area that can be readily sampled for the presence of cryptic juveniles (Davis 1995, 

Rogers-Bennett et al. 2004). ARMs will be used to help establish substrate for juveniles being 

stocked into the wild and to aid in surveys to recover these juveniles to quantify growth and 

survival. 

Studies are needed to compare survival using natural, enhanced natural habitats, and fully 

artificial habitats. The chief difficulty is that the list of potential variables that could be 

important is very long and the costs of monitoring success of a particular treatment quite high. 

Hence, good judgments of what variables to select among the many as well as strong 

experimental protocols are needed. Clearly an important criterion for selecting one set of 

variables over another is the potential cost effectiveness of a particular strategy. 

Size-at-planting 

Studies conducted around the world suggest that the highest annual survival rates of planted 

abalone are approximately 75% (Leighton 1989, Saito 1984, Sweijd et al. 1998, McCormick et 

al. 1994, Davis 1995). Some of these studies suggest that small abalone (< 90 mm) experience 

higher mortality rates than larger abalone, while other studies report the opposite. Survival rates 

for planted abalone may be biased by the inability of the investigator to get accurate counts on 

cryptic, small abalone inhabiting complex habitats. Other influences on juvenile survival include 

emigration and predation. 
White Abalone Recovery Plan 

 APPENDIX E 

E-5

Initially, a tag evaluation study using surrogate species first, and ultimately juvenile and young 

adult white abalone of the sizes that will be planted (0.3-100 mm), will be conducted. In this 

way, monitoring field plant survival will be possible. Experimental planting of individuals (< 

100 mm) will be conducted with excess animals (see White Abalone Disposition of Excess 

Individuals Plan) or with a surrogate species if excess individuals are not available, to determine 

which variables (e.g., size, age, bottom habitat type, depth) are most important to the recruitment 

success of the surrogate abalone. The primary, but not the first, field planting program will 

utilize larger-sized animals (10 cm; ~4-year-old) based on the assumptions that larger abalone 

would be immediately able to contribute to the reproducing population, exhibit lower natural 

mortality, and be easier to monitor. In the experimental seeding program, many field plants with 

larvae, postlarvae, and young and advanced juvenile white abalone will be carried out during the 

second and third years of the program. If the experimental planting program indicates that 

abalone of smaller sizes exhibit acceptably high survival relative to plants with larger abalone, 

then the sizes of individuals used in the primary planting program will be modified. 

Study Plan

Southern California mainland and Channel Island sites will be surveyed for bottom type, 

topography, algal community and potential predator and competitor species. Most appropriate 

sites will be located by GPS, marked by submerged buoys and bottom transect lines, and 

thoroughly mapped. Initially these areas will be relatively small (100 m2

). This restriction 

should facilitate direct observations by ROV and divers working at depths exceeding 30 m. 

Late stage larval plants 

Initial spawnings in the hatchery will produce larvae for introduction to the juvenile 

rearing system and for studies on thermal tolerance, substrate acceptance, and food 

utilization. As stocking densities in larval settling tanks reach optimal levels (ca 0.1/cm2), 

excess larvae may be available for use in the first experimental field plants. 

Larvae 5-10 days old, cultured at 15 - 18o

C, are competent to settle and metamorphose to 

the postlarval stage. Settlement may be delayed by holding larvae at a lower temperature 

(e.g., 12o

C) thereby acclimating to temperatures at the stocking sites. At that stage larvae 

may be transported to the field in plastic bags, taken to the bottom site by divers, inverted 

(turned inside-out) and placed on the bottom beneath a small rock. Most larvae will 

release immediately while others clinging to the bag will likely be dislodged soon 

thereafter to attach to the local substrate. Spot releases of about 10,000 larvae/bag will 

provide a concentration sufficient to yield, at a 5% survival rate, 500 juveniles dispersed 

broadly over the surrounding bottom. These progeny could be detectable after six 

months as juveniles approximately 1 cm in shell length. Earlier sampling, if the area 
White Abalone Recovery Plan 

 APPENDIX E 

E-6

provides an abundance of small rock which could be placed in sealed plastic bags for 

return to the laboratory, will allow detection of postlarvae and early juveniles. 

The particular approach taken for larval seeding will depend on the characteristics of the 

bottom at a given site. Preliminary study will suggest specific locations where larvae and 

early juveniles will encounter appropriate microenvironment and shelter and will suggest 

planting densities that yield the highest survival rates. Greatest value will be realized 

from stocking which are well planned and allow careful monitoring to establish survival, 

dispersal and growth. These efforts will be part of the white abalone restoration program. 

Very possibly graduate students will be enticed to conduct research focused on the 

ecology of seeded white abalone. 

Juvenile seeding strategies

In earliest attempts to plant juvenile hatchery-reared abalone in California and Mexico 

extreme site-specific losses occurred due to predation during and shortly after release 

(Tegner and Butler 1985 Rogers-Bennett and Pearse 1998). Studies have shown that 

juvenile abalone transported to the field and planted on the sea bottom within protective 

shelters are not handled, experience minimal stress, and may show high survival 

(Leighton 1985, 1989). In one study, time-lapse photography was employed to study the 

behavior and activity of potential predator species when juvenile abalone were planted 

using a Atrickle filter cube.@ Juveniles moved out of the shelters within 24-48 hours to 

find natural shelter among rock and crevices on the bottom. Sheltered temporarily from 

opportunist predation, losses were negligible. No empty shells were found in follow-up 

surveys; a typical result when these multilevel substrates are used. This style shelter, as 

well as others that may be developed, will be used for white abalone field plants. Each 

cubic foot trickle filter cube will hold several hundred 1 cm juveniles. These structures 

are placed on the bottom near appropriate rock outcrops. A given seeding operation will 

use many planting modules and accommodate thousands of seed. 

Larger juveniles and young adults (to 10 cm) can also be released during the white 

abalone population enhancement program. Results from matrix models of white abalone 

show that enhancing larger juveniles had more of an impact on population growth than 

enhancing smaller juveniles (Rogers-Bennett and Leaf 2006). Stocking modules may be 

composed of many different sizes and configurations. Larger abalone merely require 

planting modules with larger internal structuring. If larger abalone are planted singly 

onto the natural substratum, tests must be performed to show opportunist predation is not 

a threat to their survival. Larger abalone should also be tagged to identify them as part of 

the abalone enhancement program. 

Behavior 
White Abalone Recovery Plan 

 APPENDIX E 

E-7

Hatchery-produced or captive abalone may exhibit behavioral deficiencies (e.g., reduced 

foraging capability, reduced ability to migrate, insensitivity to certain predator species) (Osumi, 

1999). In spite of these possible deficiencies, evidence suggests that captive abalone could be 

trained to better avoid predators and to forage by acclimating hatchery-reared animals to a more 

natural setting prior to planting (e.g., presence of substrate and other organisms; Schiel and 

Welden 1987). For example, abalone may be induced to rear up from the substrate and Acapture@

kelp, their primary food source. It is also possible that exposure to known predators, such as the 

sun star (Pycnopodia helianthoides), may induce an escape response, scaring the abalone into 

moving away from the predator. The possibility of better acclimatizing cultured white abalone 

prior to field planting requires that their behavioral responses after exposure to prey, predators 

and competitors can be assessed (see White Abalone Disposition of Excess Individuals Plan). 

Genetics 

More genetic studies are needed however population densities of white abalone in the field are so 

low that genetic considerations of stocking F1 generation individuals into areas where their 

parents were captured will be a lower priority for the recovery plan (see White Abalone Genetics 

Management Plan). Once the stocking program has been successful and more genetic 

information is gained concerns regarding the genetic background of families may become a 

higher priority. 

Stocking Modules 

Past failures in California with planting juvenile and young adult abalone may in part have been 

due to high mortality resulting from poor release methods (Tegner and Butler 1985, Tegner 

2000). High planting mortality was circumvented when protective shelters or planting modules 

were used to transfer and plant young abalone (Leighton 1985, 1989, 2000). This approach 

appears to substantially reduce initial stocking mortality by minimizing predator-signaling 

secretions previously caused through stress by excessive handling and improper treatment in 

transfer from hatchery to ship to planting site (Leighton 1989). The use of planting modules is 

now also being tested elsewhere with abalone up to 2.5 inches (6.25 cm) (e.g., in South Africa 

and Australia, Sweijd et al. 1998). Use of modules of various designs have reduced the costs 

(time and money) in the field planting effort. Secured to the bottom such structures serve as 

landmarks identifying the release spots and facilitate subsequent monitoring strategies. 

The use of numerous, small modules allows the distribution of small numbers of seed into more 

protected habitat over a wider area, but requires more effort. The use of larger modules requires 

less effort, and concentrates larger numbers of juveniles into a smaller area, with potentially less 

protection. Subsequent survival and growth are affected by the location of planting modules 

with respect to the availability of food, cryptic habitat, and predators. If structured to 

accommodate a range of sizes of abalone, modules themselves may also serve as preferred 

habitat. This needs to be scientifically assessed. Much larger and permanent modules of precast 
White Abalone Recovery Plan 

 APPENDIX E 

E-8

concrete as are employed in Japan (Sheehy and Vik 1981) would also allow for containment of 

instrumentation to monitor environmental variables (e.g., temperature, salinity, currents). 

A wide variety of designs and structures of juvenile abalone planting modules have been tested 

here and in South Africa such as those formed from small chicken-wire enveloped tubes, filled 

with rocks or shell, and empty PVC tubes with small holes drilled through their top surface to 

allow juveniles to be introduced to the module and allow their emigration, once planted. In some 

tests, juvenile abalone are anaesthetized from grow-out tanks, counted and poured into tube 

modules. They are allowed to recover in a high water flow environment for 24-48 hours. 

Divers then place the tubes, with the young abalone, into cracks and crevices in suitable habitats. 

Some modules of other design, such as the trickle filter cubes, are placed in grow-out tanks 

where the abalone aggregate within the structures on their own. In other studies, box structures 

with 3x6 inch spring-operated doors held with magnesium-wire timed releases, have been 

similarly tested. Nested semi-circular tubes attached to a steel plate have also been used 

successfully (Sweijd et al. 1998, De Waal and Cook 2001). However, simplicity, commercial 

availability, cost and efficiency favor the use of Atrickle filter@ PVC planting modules described 

by Leighton (1985, 1989, 2000). 

The use of modules as a survival/recruitment assessment tool is promising. Assuming abalone 

will utilize these artificial habitats as they do co-existing natural habitat, the modules can be 

outfitted with instrumentation, retrieved for top-side assessment, and returned to the bottom for 

future sampling. Channel Islands National Park has deployed and monitors 7-15 modules that 

contained red abalone, Haliotis rufescens, at each of more than 10 locations. They were first 

tested in 1989, and the relatively massive cinder block test modules are still in place and 

monitored regularly (Davis 1995). While the maximum retention time for red abalone in these 

prototype modules was 2-3 years, design improvements and modifications of deployment 

protocol may improve retention times in modules currently deployed by the CDFG. These 

modules are also being used to monitor red abalone recruitment in northern California (RogersBennett et al. 2004) and northern abalone in Canada (DeFrietas 2003). Additional effort is 

planned in southern California as part of the white abalone recovery plan at Santa Rosa Island. 

The results from these studies should reveal natural variation in recruitment and help in the 

planning of white abalone stocking. 

Monitoring the Performance of a Field Planting Program 

Clearly, monitoring performance of the stocking program and ultimately the rate of recovery is 

of key importance. To monitor performance planting sites will be surveyed on a regular basis 

and all planted animals must be marked to distinguish them from wild stock. Genetic research 

and tools may also prove valuable for the development of a genetic marker for monitoring the 

growth and survival of captive-bred white abalone that are field planted at sizes too small (< 10 

mm) for traditional tagging methods to be used (see details in Genetics Management Plan). 

Dietary banding is used to mark juvenile abalone in the hatchery (Leighton 1985, 2000). 

Hatchery-produced juveniles are easily distinguished from natural recruits using this technique. 
White Abalone Recovery Plan 

 APPENDIX E 

E-9

Stainless steel tags have successfully been applied to abalone larger than 2 inches (5 cm), and 

have survived on at least one abalone for 16 years (Haaker and Tanaguchi 1996). Bee tags have 

been glued to the outside of smaller individuals however their longevity in the field has not been 

tested. Much as red and brown algae are fed to create dietary bands, specific food additives may 

be developed for use in hatchery animals that result in distinct and unnatural color markers in 

abalone shells. Florescent tags which bind to newly deposited calcium have also been used to tag 

hatchery produced juveniles. Other possibilities for marking advanced juveniles include coded 

wire tags, artificial and pure dyes, (although there is concern that strangely colored shells might 

increase predation), radiochemical markers, and even acoustic transponders. These and other 

approaches differ in cost per individual, tag longevity, and the size of animal for which the tag is 

appropriate, as well as the method of detection. 

The ability to measure growth, survival, reproductive output of field planted animals can be 

achieved if animals are planted in areas where white abalone were known to have occurred, but 

have gone locally extinct. The ability to collect these data will be enhanced if genetic markers 

can be developed that distinguish broodstock and their offspring from wild animals (see Genetics 

Management Plan). 

References

Davis, G.E. 1995. Recruitment of juvenile abalone (Haliotis spp.) measured in artificial habitats. 

Mar. Freshwater Res. 46: 549-554. 

DeFreitas, B. 2003. Estimating juvenile northern abalone (Haliotis kamtschatkana) abundance 

using artificial habitats. J. Shellfish Res. 22:819-823. 

 

De Waal, S. and P. Cook. 2001. Quantifying the physical and biological attributes of successful 

ocean seeding for farm-reared juvenile abalone (Halitotis midae). J. Shellfish Res. 20: 857-861. 

Estes, J.A., and G.R. VanBlaricom. 1985. Sea-otters and shellfisheries. pp. 187-235. In J.R. 

Beddington, R.J.H. Beverton, and D.M. Lavigne (eds.). Marine mammals and fisheries. George, 

Allen, and Unwin, London, United Kingdom. 

Gotshall, D.W. 1977. Fishwatcher’s guide to the inshore fishes of the Pacific coast. Sea 

Challengers. Monterey, California. 

Haaker, P.L. and Taniguchi, I.K. (1996) A red abalone tag return after 16 years at liberty. 

California Fish and Game 82(3) 141-143. 

Kojima, H. 1995. Evaluation of abalone stock enhancement through the release of hatchery 

reared seeds. pp. 689-695. In S. A. Shepherd, R. W. Day, and A. J. Butler (eds.). Progress in 

Abalone Fisheries Research. Mar. Freshw. Res. 
White Abalone Recovery Plan 

 APPENDIX E 

E-10

Leighton, D.L. 1968. A comparative study of food selection and nutrition in the abalone, 

Haliotis rufescens Swainson, and the sea urchin, Strongylocentrotus purpuratus (Stimpson). 

Ph.D. Dissert., Univ. Calif. San Diego.

Leighton, D.L. 1985. Early growth of the green abalone in hatchery and field. Diving for 

Science. Proc. Joint Internat. Scientif. Diving Symp., La Jolla, Calif. :235-246. 

Leighton, D.L. 1989. Abalone (genus Haliotis) mariculture on the North American Pacific 

Coast. U.S. Dept. Commerce, Fishery Bulletin 87:689-702. 

Leighton, D.L. 2000. Seeding for fishery enhancement and sea floor ranching. Chapter XIV In: 

The Biology and Culture of the California Abalones. Dorrance Publ. Co. Pittsburgh, PA. 

McCormick, T.B., Herbinson, K., Mill, T.S., and Altick, J. 1994. A review of abalone seeding, 

possible significance, and a new seeding device. Bull. Mar. Sci. 55(2-3), 680-693. 

McCormick, T.B. 2000. Abalone (Haliotis spp.) aquaculture: present status and a stock 

enhancement tool. In Workshop on Rebuilding Abalone Stocks in British Columbia. Edited by A 

Campbell. Can Spec. Publ. Fish. Aquat. Sci. 130. pp. 55-60. 

Miner, M.C., Altstatt, J.M., Raimondi, P.T. and T.E. Minchinton 2007. Recruitment failure and 

shifts in community structure following mass mortality limit recovery prospects of black 

abalone. Mar. Ecol. Prog. Ser. 327:107-117. 

Osumi, K. 1999. Stock enhancement and habitat association of juvenile paua (Haliotis iris) in 

northeastern New Zealand. M.Sc. University of Auckland, New Zealand. 

Preece, P.A., Shepherd, S.A., Clarke, S.M. and Keesing, J.K. 1997. Abalone stock enhancement 

by larval seeding: effect of larval density on settlement and survival. Moll. Res. 18(2), 265-273. 

Rogers-Bennett, L. and R.T. Leaf. 2006. Elasticity analyses of size-based red and white abalone 

matrix models: Management and conservation. Ecological Applications 16:213-224. 

Rogers-Bennett, L., Allen, B.L. and G.E. Davis. 2004. Measuring abalone (Haliotis spp.) 

recruitment in California to examine recruitment overfishing and recovery criteria. J. Shellfish 

Res. 23:1201-1207. 

Rogers-Bennett, L., P.L. Haaker, K.A. Karpov and D. J. Kushner. 2002. Using spatially explicit 

data to evaluate Marine Protected Areas for abalone in southern California. Conservation 

Biology 16:1308-1317. 
White Abalone Recovery Plan 

 APPENDIX E 

E-11

Rogers-Bennett, L. and J.S. Pearse. 1998. Experimental seeding of hatchery-reared juvenile red 

abalone Haliotis rufescens in northern California. J. Shellfish Res. 17:877-880. 

Saito, K. 1979. Studies on the propagation of Ezo abalone, Haliotis discus hannai, analysis of 

the relationship between transplantation and catch in Funka Bay coast. Bull. Japan. Soc. Sci. 

Fish. 45:695-704. 

Saito, K. 1984. Ocean ranching of abalones and scallops in northern Japan. Aquaculture 39, 361-

373. 

Schiel, D.R. and Welden, B.C. 1987. Responses to predators of cultured and wild red abalone, 

Haliotis rufescens , in laboratory experiments. Aquaculture 60 (3-4): 173-188. 

Schiel, D.R. 1993. Experimental evaluation of commercial-scale enhancement of abalone Haliotis iris populations in 

New Zealand. Mar. Ecol. Prog. Ser. 97:167-181. 

Sheehy, D., and S, Vik. 1981. Aquaculture: Developments in East Asia. Water Spectrum., Fall 

(1981):26-37. 

Sweijd, N., Snethlage, Q., Harvey, D., and Cook, P. 1998. Experimental abalone (Haliotis 

midae) seeding in South Africa. J. Shellfish Res. 17(3), 897-904. 

Tegner, M.J. 2000. Abalone (Haliotis spp.) enhancement in California: what we=ve learned and 

where we go from here. In Workshop on Rebuilding Abalone Stocks in British Columbia. 

Edited by A Campbell. Can Spec. Publ. Fish. Aquat. Sci. 130. pp. 61-71. 

Tegner, M.J. and R. Butler. 1985. The survival and mortality of seeded and native red abalone, 

Haliotis rufescens, on the Palos Verdes Peninsula. Calif. Fish and Game 71:150-163. 

Tutschulte, T.C. 1976. The comparative ecology of three sympatric abalones. PhD dissertation. 

University of California, San Diego. 

VanBlaricom, G.R. 1993. Dynamics and distribution of black abalone populations at San 

Nicolas Island, California. Pages 323-334 In Third California Islands Symposium: Recent 

advances in research on the California Islands. Edited by F.G. Hochberg. Santa Barbara Museum 

of Natural History, Santa Barbara, California.