Black Abalone

(Haliotis cracherodii)

Five-Year Status Review: Summary and Evaluation

July 2018

Photo Credit: Susan Wang, NMFS

National Marine Fisheries Service

West Coast Region

Protected Resources Division

Long Beach, California
TABLE OF CONTENTS

1.0 GENERAL INFORMATION.............................................................................................. 1

1.1 Reviewers......................................................................................................................... 1

1.2 Methodology used to complete the review ...................................................................... 1

1.3 Background ...................................................................................................................... 1

1.3.1 FR Notice citation announcing initiation of this review........................................... 1

1.3.2 Listing history ........................................................................................................... 1

1.3.3 Associated rulemakings............................................................................................ 2

1.3.4 Review History ......................................................................................................... 2

1.3.5 Species’ Recovery Priority Number at start of five-year review.............................. 2

1.3.6 Recovery Plan or Outline.......................................................................................... 2

2.0 REVIEW ANALYSIS ......................................................................................................... 2

2.1 Application of the 1996 Distinct Population Segment (DPS) Policy .............................. 2

2.2 Recovery Criteria ............................................................................................................. 3

2.3 Updated Information and Current Species Status............................................................ 3

2.3.1 Biology and Habitat .................................................................................................. 3

2.3.2 Five-Factor Analysis (threats, conservation measures, regulatory mechanisms)... 10

2.4 Synthesis......................................................................................................................... 19

3.0 RESULTS .......................................................................................................................... 21

3.1. Recommended Classification......................................................................................... 21

3.2. New Recovery Priority Number..................................................................................... 21

4.0. RECOMMENDATIONS FOR FUTURE ACTIONS ....................................................... 21

5.0 REFERENCES .................................................................................................................. 24
Black Abalone 5 - Year Status Review July 2018 | 1

5-YEAR REVIEW

Black Abalone (Haliotis cracherodii)

Current Classification: Endangered

1.0 GENERAL INFORMATION

1.1 Reviewers

Lead Regional or Headquarters Office: National Marine Fisheries Service (NMFS) West 

Coast Region (WCR) – Chris Yates, Assistant Regional Administrator for Protected Resources, 

562-980-4007

Cooperating Science Center(s): NMFS Southwest Fisheries Science Center – Kristen Koch, 

Science and Research Director, 858-546-7081

1.2 Methodology used to complete the review

This five-year review was led by the NMFS West Coast Region. Much of the updated 

information on the species’ biology and habitat was compiled by two student interns in the 

summer of 2016: Alyssa Braciszewski and Lara Slatoff. The primary sources of information and 

data for this review came from reports, publications, and information available from ongoing 

studies and reviews that have become available since the status review completed by 

VanBlaricom et al. (2009). We gathered information through: 1) literature searches on various 

search engines (e.g., Google Scholar, Research Gate, Web of Science); 2) publication of a 

Federal Register (FR) notice soliciting new information about black abalone; and 3) email and 

phone contact with abalone experts at universities and state and federal government agencies. 

Section 2.3 (Updated Information and Current Species Status) was reviewed by the Black 

Abalone Recovery Team (BART), to ensure that this Section accurately presents the best 

available information that has become available since the 2009 Status Review on the species’ 

biology, habitat, status, and threats. The BART consists of research biologists and resource 

managers representing several agencies and institutions with expertise on abalone, rocky 

intertidal and subtidal habitats, and conservation.

1.3 Background

1.3.1 FR Notice citation announcing initiation of this review 

81 FR 93902; 22 December 2016

1.3.2 Listing history

Original Listing

Federal Register notice: 74 Federal Register 1937 
Black Abalone 5 - Year Status Review July 2018 | 2

Date listed: January 14, 2009

Entity listed: Species

Classification: Endangered

1.3.3 Associated rulemakings 

Critical Habitat Designation: 76 Fed. Reg. 66806, October 27, 2011 

1.3.4 Review History

This is the first, formal five-year review for black abalone. The original status review was 

completed in 2009 (VanBlaricom et al. 2009) for the final listing decision. 

1.3.5 Species’ Recovery Priority Number at start of five-year review

Black abalone have a Recovery Priority Number of 51

, based on criteria in the Recovery 

Priority Guidelines (55 FR 24296, 15 June 1990). The Recovery Priority Number is 

based on three criteria: the magnitude of threat, potential for recovery, and potential for 

conflict with economic activities. Black abalone were assigned a Recovery Priority 

Number of 5 out of a range of 1 (high) to 12 (low), based on the species’ moderate

extinction risk, high recovery potential (e.g., primary threats are disease and the resulting 

low densities, which may be addressed by monitoring, management, and population 

enhancement efforts), and potential for conflicts with economic interests (e.g., if 

restrictions are needed to minimize or avoid effects on rocky intertidal habitats and 

coastal water quality).

1.3.6 Recovery Plan or Outline 

The Recovery Plan Outline for black abalone was published in 2016 (NMFS 2016). 

NMFS is currently developing the Draft Recovery Plan for black abalone. 

2.0 REVIEW ANALYSIS

2.1 Application of the 1996 Distinct Population Segment (DPS) Policy

2.1.1 Is the species under review a vertebrate?

_____Yes.

__X__No.

 1 On 31 May 2017, NMFS published draft revised Listing and Recovery Priority guidelines (82 FR 24944). 

Applying the draft guidelines, black abalone would have a new proposed Recovery Priority Number of one, based 

on the species’ high demographic risk and high recovery potential.
Black Abalone 5 - Year Status Review July 2018 | 3

2.2 Recovery Criteria

2.2.1 Does the species have a final, approved recovery plan containing objective, 

measurable criteria?

____ Yes

__X_ No (a draft recovery plan is in development).

2.3 Updated Information and Current Species Status

2.3.1 Biology and Habitat

2.3.1.1 New information on the species’ biology and life history

Black abalone are marine snails, with one shell and one large muscular foot used for locomotion 

and adhering to rocky substrates. They are relatively long-lived (estimated to live up to 30 

years), have separate sexes, and are “broadcast” spawners, meaning that both sexes shed their 

gametes into the sea and fertilization is entirely external. Successful reproduction is dependent 

on spatial and temporal synchrony among spawning individuals; that is, males and females in 

close proximity to one another (within meters) and spawning simultaneously have a higher 

likelihood of reproductive success. An experimental simulation of black abalone spawning 

employed release of inert neutrally-buoyant particles in two size categories similar in size to eggs 

and sperm in black abalone habitat at San Nicolas Island in southern California (Blaud 2013). 

Data were consistent with the premise that probability of fertilization may increase if spawning 

males and females are within four to five meters of one another. 

Natural recovery of severely-reduced abalone populations is likely a slow process, because 

having few reproductive adults reduces reproductive success and eventual recruitment of larval 

abalone. Studies indicate that a critical minimum adult density is needed to support successful 

reproduction and recruitment, though estimates of this critical density vary (Babcock and 

Keesing 1999: 0.15 – 0.20 abalone per m2

; Neuman et al. 2010: 0.34 abalone per m2; Tissot 

2007: 0.75 – 1.1 abalone per m2

). However, successful fertilization and recruitment is possible in 

populations that are below this minimum density (likely due to their aggregative nature or habitat 

preferences), as has been observed at some populations in southern California where the 

abundance and density of black abalone had declined severely due to withering syndrome. 

Recruitment and increasing numbers of black abalone have been observed at several sites 

throughout southern California (Richards and Whitaker 2012, Eckdahl 2015, VanBlaricom 2017, 

unpublished data).
Black Abalone 5 - Year Status Review July 2018 | 4

Little new information on black abalone biology or life history has become available since the 

2009 Status Review. Studies on other abalone species have been published that may inform us 

about black abalone reproductive biology and immunity. Studies involving green abalone 

(Haliotis fulgens) and red abalone (H. rufescens) may be most relevant given similarities with 

black abalone in their habitat use, because they also inhabit intertidal and shallow subtidal 

habitat along the California coast. Vélez-Arellano (2016) studied the movement of nutrients in 

green abalone during gonad development and found that as the gonads develop, the 

concentration of lipids, proteins, and carbohydrates decreases in the foot and increases in the 

gonad and digestive gland. This is consistent with observations in black abalone indicating that 

the foot muscle shrinks during increased gonad development (Webber 1970). New information 

from red abalone studies explains some of the chemical signaling that occurs during spawning to 

increase fertilization and prevent hybridization. Krug et al. (2009) found that eggs have high 

concentrations of tryptophan to attract sperm to conspecific eggs, even to the extent of altering 

the sperm’s swimming behavior. Fertilization success peaks during the 30 minute period 

following spawning and decreases to low levels at 50 minutes, corresponding with when the 

release of tryptophan stops (Krug et al. 2009).

Research on captive breeding of black abalone is ongoing and will likely provide additional 

information on the species’ biology and life history in the future. Other studies are also ongoing 

to examine abalone vision, digestive physiology, and the genetic components of resistance to 

withering syndrome. Results for these studies are not currently available, but may be 

incorporated into the next review.

2.3.1.2 Abundance, population trends, demographic features, or demographic 

trends

Long-Term Population Monitoring

Long-term monitoring of black abalone populations has been conducted throughout the coast of 

California and is ongoing. These monitoring efforts are largely coordinated by the Multi-Agency 

Rocky Intertidal Network (MARINe), a partnership of agencies, universities, and private groups 

that not only conducts intertidal surveys, but provides this information to the public. Monitoring 

has been conducted since the mid-1970s and 1980s in some areas and provides valuable 

information on population trends and the progression of withering syndrome along the coast. 

Since the ESA listing of black abalone, population monitoring has expanded to include new sites 

(e.g., Golden Gate National Recreation Area, Point Reyes National Seashore Area, and the 

Farallon Islands; Eckdahl et al. 2012, Roletto et al. 2015), as well as revisiting areas that have 

not been surveyed in over 10 years, providing a more comprehensive understanding of the 

species’ status.
Black Abalone 5 - Year Status Review July 2018 | 5

Population Trends

Black abalone are believed to be naturally rare at the northern and southern extremes of their 

range, with the highest abundances historically south of Monterey, particularly at the Channel 

Islands off southern California. Beginning in the mid-1980s, black abalone populations began to 

decline dramatically due to the spread of withering syndrome. Overall, the disease caused 

declines of more than 80% in populations throughout southern California and as far north as 

Cambria in San Luis Obispo County; in populations south of Point Conception, declines of more 

than 90% have occurred (Neuman et al. 2010). Less severe declines (approximately 50%) have 

been documented even further north, into southern Monterey County (Miner 2017, unpublished 

data). 

Most black abalone populations affected by withering syndrome remain at low densities, below 

the estimated levels needed to support successful reproduction and recruitment (Babcock and 

Keesing 1999: 0.15 – 0.20 abalone per m2

; Neuman et al. 2010: 0.34 abalone per m2; Tissot 

2007: 0.75 – 1.1 abalone per m2

). Data for 2002-2006 indicate that population densities exceed 

this threshold value in areas not yet affected by the disease (north of Cambria; densities ranged 

from 1.1 to 10.5 abalone per m2

), whereas population densities fall below this threshold value, 

many significantly so, in areas severely affected by the disease (south of Cambria; densities 

range from 0 to 0.5 abalone per m2

) (Neuman et al. 2010). However, despite these low densities, 

researchers have observed evidence of recent recruitment and increases in abundance at several 

locations throughout southern California, including the Palos Verdes Peninsula, Laguna Beach,

Santa Cruz Island, San Miguel Island, and San Nicolas Island (Richards and Whitaker 2012, 

Eckdahl 2015, VanBlaricom 2017, unpublished data). 

The disease has also affected populations in Baja California, but little is known about the 

species’ status in Mexico. According to Searcy-Bernal et al. (2010) black abalone virtually 

disappeared from mainland Baja California but were still present on Isla Guadalupe and 

supported fishery harvest in 2004-2008. In more recent years, anecdotal evidence suggests that 

populations are beginning to recover in mainland areas (pers. comm. with Ricardo SearcyBernal, Universidad Autonoma de Baja California (UABC), 16 Aug 2016; pers. comm. with 

Fabiola Lafarga de la Cruz, Center for Scientific Research and Higher Education of Ensenada 

(CICESE), 18 Aug 2016). In particular, evidence of recruitment events was observed at mainland 

sites in 2014 (pers. comm. with Ricardo Searcy-Bernal, UABC, 22 Aug 2016) and 2016 (pers. 

comm. with Fabiola Lafarga de la Cruz, CICESE, 20 Oct 2016). 

Demographic Trends and Effects of Withering Syndrome

Observations of recruitment and increasing numbers despite low densities indicate that factors 

other than the number of abalone per square meter need to be considered when assessing 

population viability. Population growth appears to be directly correlated with decreasing distance 

between individuals (Blaud 2013). Black abalone tend to be found in aggregations; reasons for 
Black Abalone 5 - Year Status Review July 2018 | 6

this can include an increased ability to capture drift algae (for food), a preference for similar 

habitat qualities, reduced predation risk, or a response to other environmental cues (Richards and 

Whitaker 2012, Blaud 2013). This tendency to form aggregations increases fertilization success, 

because individuals are in close proximity to one another, and has likely contributed to the 

successful reproduction and recruitment observed in populations despite their low densities 

(Richards and Whitaker 2012, Blaud 2013, Eckdahl 2015, VanBlaricom 2017, unpublished data). 

Withering syndrome continues to affect populations, although disease-related mass mortalities 

have not been observed in the wild since the 1990s (Neuman et al. 2010). The pathogen that 

causes withering syndrome (Candidatus Xenohaliotis californiensis, or Ca.Xc) is a bacterium 

called a Rickettsiales-like organism that has been detected in all coastal marine waters of central 

(Friedman and Finley 2003) and southern California (Moore et al. 2002) up to south Sonoma 

County (Bodega Head; pers. comm. with Jim Moore, California Department of Fish and Wildlife 

(CDFW)/Bodega Marine Lab (BML), 20 Nov 2015), and has also been found at Southeast 

Farallon Island (pers. comm. with Jim Moore, CDFW/BML, cited in VanBlaricom et al. 2009). 

Disease transmission and manifestation is intensified when local sea surface temperatures 

increase by as little as 2.5 oC above ambient levels (i.e., to over 17-18°C) and remain elevated 

over a prolonged period of time (i.e., a few months or more) (Friedman et al. 1997, Raimondi et 

al. 2002, Harley and Rogers-Bennett 2004, Vilchis et al. 2005). Recent data suggest that 

fluctuating water temperatures can also increase transmission of Ca.Xc in black abalone (BenHorin et al. 2013). During the 2015-2016 El Niño event, researchers found more withered black 

abalone than in the previous 5-10 years, including potentially withered black abalone at sites 

north of Cambria, near Santa Cruz, but did not report mass mortalities (pers. comm. with Karah 

Ammann, University of California Santa Cruz (UCSC), 8 Mar 2016). A bacteriophage has been 

discovered that infects the pathogen, reduces its pathogenicity, and improves the survival of 

infected abalone (Friedman and Crosson 2012, Crosson et al. 2014, Friedman et al. 2014a, b). 

Genetically-based disease resistance may also exist and is the subject of ongoing studies at the 

University of Washington (VanBlaricom et al. 2009, Friedman et al. 2014a).

Disease research has continued to advance our knowledge of withering syndrome and its effects 

on black abalone and other abalone species along the coast. Development of a quantitative PCR 

method has allowed detection of the pathogen in water samples and in individual abalone 

(Crosson et al. 2014, Friedman et al. 2014b). Research is ongoing to evaluate the role of Ca.Xc 

effluent (from abalone facilities) in disease transmission and the role of the bacteriophage in the 

disease’s effects on abalone populations and will likely provide valuable information in the 

coming years.
Black Abalone 5 - Year Status Review July 2018 | 7

2.3.1.3 Genetics, genetic variation, or trends in genetic variation

The mass mortalities caused by withering syndrome may have reduced the species’ genetic 

diversity, although studies have not yet been conducted to evaluate this potential loss of 

diversity. Genetic diversity has been evaluated at broad spatial scales across the species’ range in 

California using allozymes, mitochondrial DNA sequencing, and microsatellite genotyping 

(Hamm and Burton 2000, Chambers et al. 2006, Gruenthal and Burton 2008, Beldade et al. 

2012). Larval dispersal appears to be limited, with populations composed predominately of 

locally spawned and recruited individuals, resulting in genetic differentiation between island 

populations and mainland populations (Hamm and Burton 2000, Chambers et al. 2006, 

Gruenthal and Burton 2008). Beldade et al. (2012) developed and applied a set of eight 

microsatellite markers to test for polymorphism in two black abalone populations, one affected 

by the disease and one not affected by the disease. They found high genetic diversity in both 

populations, likely due to historically-large population sizes at both locations, but no significant 

differences in genetic diversity between populations (Beldade et al. 2010). The markers can be 

used to evaluate changes in genetic diversity in the future. New methods, such as single 

nucleotide polymorphisms (SNPs), may also be applied to the species to examine genetic 

connectivity and structure (Gruenthal et al. 2014).

2.3.1.4 Taxonomic classification or changes in nomenclature

There have been no changes in nomenclature or taxonomic classification for black abalone. 

VanBlaricom et al. (2009) describes a previously identified subspecies Haliotis cracherodii 

californiensis found at Guadalupe Island off Baja California, but states that the most recent 

assessment considered all previously described subspecies to be varieties representing 

ecomorphs or examples of shell deformations that are synonymous with a single species, H. 

cracherodii. Since the last review, there has been no additional information that would change 

this classification.

2.3.1.5 Spatial distribution, trends in spatial distribution, or historic range 

Historically, black abalone were documented to occur from Crescent City (Del Norte County, 

California) to southern Baja California (Geiger 2004), but the current range is estimated to 

extend from Point Arena, California, south to Bahia Tortugas, Mexico, including offshore islands 

(Figure 1; 74 FR 1937, 14 January 2009). Black abalone occupy rocky intertidal habitats from 

the upper intertidal to 6 meters depth, but are most commonly observed in the middle and lower 

intertidal, in habitats with complex surfaces and deep crevices that provide shelter for juvenile 

recruitment and adult survival. At sites along the central California coast, black abalone have 

been found in areas with more crevice habitat, possibly as a result of increased sea otter 

populations (Raimondi et al. 2015). Other factors may also contribute to the higher abundances 

of black abalone observed in crevices or habitats with more refuge. For example, crevice habitat 

may provide thermal refugia to reduce the risk of thermal stress in the intertidal (Duncan 2017). 
Black Abalone 5 - Year Status Review July 2018 | 8

Long-term black abalone monitoring continues throughout the California coast and shows that 

black abalone continue to occupy sites throughout their range, although they persist at low 

densities or were locally extirpated at sites along the southern California and Baja California 

mainland due to the disease. However, as mentioned in Section 2.3.1.2, black abalone focused 

surveys have been conducted in recent years and have found animals in areas along the southern 

California and Baja California mainland where they had not been observed since the 1990s 

(Eckdahl 2015, pers. comm. with Ricardo Searcy-Bernal, UABC, 16 Aug 2016; pers. comm. 

with Fabiola Lafarga de la Cruz, CICESE, 18 Aug 2016). At Santa Catalina Island, two survey 

efforts were conducted, but have not found any live black abalone (Neuman et al. 2011, Obaza et 

al. 2016). Monitoring efforts need to be expanded to sufficiently evaluate the presence of black 

abalone throughout their range. 

Figure 1. Current geographic range of black abalone.

2.3.1.6 Habitat or ecosystem conditions

NMFS designated critical habitat for black abalone on 27 October 2011 (76 FR 66806; Figure 2). 

The designation encompasses rocky intertidal and subtidal habitat within five segments of the 
Black Abalone 5 - Year Status Review July 2018 | 9

California coast between the Del Mar Landing Ecological Reserve and the Palos Verdes 

Peninsula, as well as on the Farallon Islands, Año Nuevo Island, San Miguel Island, Santa Rosa 

Island, Santa Cruz Island, Anacapa Island, Santa Barbara Island, and Santa Catalina Island. San 

Nicolas Island and San Clemente Island also contain good quality habitat that supports black 

abalone populations; however, both islands are owned or controlled by the U.S. Navy and have 

Integrated Natural Resource Management Plans (INRMPS) in place that have been determined 

by NMFS to provide protections and benefits to black abalone. Under the ESA, such areas are 

not eligible for designation as critical habitat. In addition, critical habitat was not designated 

within segments of the southern California coast where black abalone may have occurred 

historically, but had not been observed in the period from 2005 to 2010. The critical habitat 

designation may be revised as the species recovers and more information becomes available.

Physical or biological features include rocky substrate (e.g., rocky benches formed from 

consolidated rock or large boulders that provide complex crevice habitat); food resources (e.g., 

macroalgae); juvenile settlement habitat (rocky substrates with crustose coralline algae and 

crevices or cryptic biogenic structures); suitable water quality (e.g., temperature, salinity, pH) for 

normal survival, settlement, growth, and behavior; and suitable nearshore circulation patterns to 

support successful fertilization and larval settlement within appropriate habitat. Critical habitat 

areas north of Cambria were generally identified as areas of high conservation value, because 

they support stable populations; contain habitat of good to excellent quality for black abalone; 

and serve as a refuge from the effects of withering syndrome due to cooler water temperatures. 

South of Cambria, changes to critical habitat features have occurred following the decline in 

black abalone. For example, increased growth of encrusting species like sponges, possibly a 

result of diminished space use by declining black abalone populations, may reduce the surface 

area for crustose coralline algae to grow, thereby reducing the quality of larval settlement habitat 

(Miner et al. 2006, VanBlaricom et al. 2009, NMFS 2011). However, in general, these critical 

habitat areas continue to represent high conservation value to the species, because they contain 

black abalone habitat of good to excellent quality (NMFS 2011).
Black Abalone 5 - Year Status Review July 2018 | 10

Figure 2. Designated critical habitat for black abalone.

2.3.2 Five-Factor Analysis (threats, conservation measures, regulatory 

mechanisms)

This section summarizes the best available information, including new information since the 

2009 Status Review, regarding the ESA’s five listing factors, which must be considered when 

determining whether a species is endangered or threatened. The five factors must also be 

evaluated when reclassifying or delisting any listed species:

(a) The present or threatened destruction, modification or curtailment of its habitat or range; 

(b) Overutilization; 

(c) Disease or predation; 

(d) Inadequacy of existing regulatory mechanisms; and 

(e) Other natural and manmade factors. 
Black Abalone 5 - Year Status Review July 2018 | 11

This analysis discusses the five listing factors and any relevant new information regarding the 

magnitude and imminence of previously identified threats to the species or emerging threats to 

the species. Overall, the threats of greatest concern include the following existing and emerging 

threats: 

• Low densities and potentially reduced genetic diversity due to historical overfishing and 

mass mortalities caused by withering syndrome 

• Disease impacts on wild populations, particularly the continued spread of withering 

syndrome, but also the spread of other pathogens or invasive species known to affect 

abalone, via aquaculture and research, food, and hobby markets

• The effects of oil spills, landslides, and response activities on black abalone and their 

habitat

• Continued illegal take of black abalone despite prohibitions on harvest

• Elevated water temperatures associated with El Niño/Southern Oscillation (ENSO) 

events and other ocean-atmosphere processes reflected by indices such as the Pacific 

Decadal Oscillation (PDO)

• Ocean acidification, associated with long-term climate change

This analysis also considers regulatory mechanisms and conservation measures that have been 

established and implemented for black abalone.

2.3.2.1 Present or threatened destruction, modification or curtailment of its habitat 

or range 

Two threats of particular concern regarding the species’ habitat or range are: contaminant spills 

and associated response activities, and increased water temperatures. 

Regarding contaminant spills and spill response activities, we primarily focus on oil spills but 

recognize that spills of other materials could also affect abalone habitat. Sources of oil spills 

could include offshore drilling platforms, pipelines, or various types of vessels. Thus, oil spills 

could occur anywhere within the species’ range. Habitat impacts include destruction of other 

intertidal organisms that black abalone rely upon for settlement cues (e.g., coralline algae), food 

(e.g., diatoms, macroalgae), and shelter. The magnitude of impacts may vary widely, depending 

on the type of material involved in the spill and local habitat features and conditions. For 

example, black abalone intertidal habitat is characterized by high wave energy, so some 

contaminant materials may be washed out naturally by waves, whereas other materials may 

persist in cracks and crevices, prolonging exposure and effects to the habitat as well as to 

individual abalone. Also, we cannot predict when, where, and how often spills will occur, 

although risk may be greater in areas adjacent to offshore oil fields and shore-based pipelines 

(e.g., Santa Barbara), or large, industrial coastal cities (e.g., Los Angeles) that experience intense 
Black Abalone 5 - Year Status Review July 2018 | 12

vessel traffic. Careful planning and coordination are needed to guide spill response and postmonitoring activities, to minimize and assess damage to abalone and their habitat. For example, 

response activities involving dispersants or the movement of personnel/equipment through the 

intertidal could affect black abalone habitat. Damage assessment should include monitoring of 

impacts to black abalone habitat from both the spill and the response activities. Spills and 

associated response activities can also directly affect the health and survival of individuals (see 

Section 2.3.2.5 Other Natural or Manmade Factors). 

Increased water temperature can result from: (1) anthropogenic thermal effluent (e.g., thermal 

discharges from power plant facilities); and (2) long-term and short-term climate change (e.g., 

global climate change, El Niño-Southern Oscillations (ENSO) events). Increased water 

temperatures can pose a risk to black abalone by reducing the quantity and quality of food 

resources (e.g., kelp; Vilchis et al. 2005) as well as inducing disease expression, accelerating 

transmission of the pathogen, and increasing disease-related mortality (Friedman et al. 1997, 

Moore et al. 2000, Raimondi et al. 2002, Harley and Rogers-Bennett 2004, Braid et al. 2005, 

Vilchis et al. 2005, Ben-Horin et al 2013). Compromised immune function as a result of longterm changes in salinity and temperature may also affect the relationship between temperature 

and withering syndrome (Morash and Alter 2015). Exposure to higher water temperatures 

resulted in significantly greater mortality caused by withering syndrome and halted growth and 

reproduction in red abalone (Vilchis et al. 2005). These results suggest that warming ocean 

temperatures are likely to have negative effects on abalone species that are adapted to cooler 

water temperatures or, in the case of black abalone, are particularly susceptible to withering 

syndrome. 

During the 2015-2016 El Niño event, researchers observed greater numbers of withered black 

abalone as compared to prior years with normal ocean temperatures, but fewer than what had 

been anticipated given the warm water temperatures. Researchers also observed evidence of 

recruitment in certain areas despite the warmer water (pers. comm. with Karah Ammann, UCSC, 

8 Mar 2016; pers. comm. with Black Abalone Recovery Team (BART), 27 July 2016). The 

presence of the bacteriophage may contribute to reducing the disease’s effects on black abalone 

populations. Individuals that survived the mass mortalities in the 1980s and 1990s may also be 

more resistant to the disease, but genetically-based resistance has been identified only in 

laboratory settings (Crosson et al. 2014, Friedman et al. 2014a). Further study and monitoring are 

necessary to understand the effects of increased water temperatures on the species.

Most of the other threats to black abalone habitat are of lower concern because they occur 

infrequently; have a narrow geographic scope; or have uncertain, indirect, and/or low potential 

impacts on black abalone. Examples of these threats include nearshore military operations, vessel 

groundings, coastal development (e.g., shore stabilization projects), cable repairs, recreational 

access, and benthic community shifts (e.g., due to the absence or reduced presence of abalone). 
Black Abalone 5 - Year Status Review July 2018 | 13

Some of the threats including sedimentation (e.g., landslides, storm-generated burial), 

fluctuations in food quality or quantity (naturally or due to factors such as kelp harvest, ocean 

warming, or non-native species), and sea level rise may have broader impacts. However, the 

effects on black abalone are uncertain and/or low. For example, sea level rise likely will occur 

over a long period of time, which may allow for abalone to adapt to changes in their habitat. 

Abalone species are also likely able to alter their foraging strategies to account for changes in 

their food supply (Kiyomoto et al. 2013). We note that in May 2017, a large landslide at Mud 

Creek on the Big Sur coast buried approximately 1,700 ft (~518 m) of coastline, likely including 

black abalone critical habitat. Continued erosion of the landslide has resulted in increased 

sedimentation and burial of black abalone habitat adjacent to the landslide (Raimondi et al. 

2017); the spatial and temporal extent of sedimentation effects is being monitored.

2.3.2.2 Overutilization for commercial, recreational, scientific, or educational 

purposes

Commercial and recreational harvest of black abalone contributed to their decline. The black 

abalone fishery in California closed in 1993, but the effects of both the fishery and disease (e.g., 

reduced local abundance and density of black abalone) remain and continue to affect the species’ 

recovery. Illegal harvest of black abalone continues to pose a threat to the species’ recovery. 

CDFW has documented 13 black abalone poaching cases between 2007 and 2012, involving a 

total of 387 black abalone (Taniguchi 2015, unpublished data). We likely do not have a complete 

record of black abalone poaching cases for this time period, as cases of poaching are difficult to 

detect and pose substantial challenges to law enforcement and judicial institutions. Continued 

high demand for abalone on the black market and illegal personal use provides a strong incentive 

for poaching. To better understand the level of poaching that is occurring and assess the impacts 

to black abalone, collection of these data and collaboration with enforcement must continue. 

Additional actions, such as increased penalties for poaching, may also be needed to deter illegal 

harvest. 

In Baja California, populations of black abalone have been depleted to such low levels that they 

are likely rarely taken. From 2004 to 2008, the species was only harvested on Isla Guadalupe 

because they could not be found in harvestable numbers on the Baja California mainland 

(Searcy-Bernal et al. 2010). Currently, fishery regulations in Mexico prohibit recreational harvest 

of abalone and any harvest of intertidal abalone (pers. comm. with Miguel del Rio Portilla and 

Fabiola Lafarga de la Cruz, CICESE, 20 July 2017). Since at least 2012, catch quotas for black 

abalone, white abalone, and red abalone have not been authorized along the west coast of Baja 

California, Mexico (Carta Nacional Pesquera 2012). Illegal harvest continues to pose a risk to 

black abalone populations in Baja California (e.g., “Restaurant owner admits to smuggling 

forbidden seafood from Mexico” by Cassia Pollock, NBC 7 San Diego, published 29 September 

2017), and this risk may increase over time if black abalone abundance begins to increase.
Black Abalone 5 - Year Status Review July 2018 | 14

2.3.2.3 Disease or predation

Withering Syndrome

Withering syndrome was identified as the primary threat to black abalone survival and recovery 

(VanBlaricom et al. 2009) and continues to threaten the species. At the same time, other diseases 

have been identified that affect abalone species worldwide and pose a threat to black abalone. 

Withering syndrome caused mass mortalities and near extirpation of black abalone throughout 

southern California and continues to spread northward along the California coast (Neuman et al. 

2010). Elevated water temperatures -- resulting from anthropogenic sources or long-term and 

short-term climate change -- allow for northward spread of both the pathogen and disease, and 

accelerate transmission (Friedman et al. 1997, Moore et al. 2000, Raimondi et al. 2002, Harley 

and Rogers-Bennett 2004, Braid et al. 2005, Vilchis et al. 2005, Ben-Horin et al 2013). Increased 

abundance and density of black abalone as populations recover may also increase disease 

transmission. Discharge of effluent from abalone farms could also facilitate transmission of the 

pathogen (Lafferty et al. 2013). DNA of Ca.Xc has been found in effluent discharged from 

abalone farms as well as in waters adjacent to abalone populations; however, it is not clear 

whether the DNA represents live pathogens that can infect animals (Friedman et al. 2014b, 

Crosson et al. in manuscript). In a recent field study, equal numbers of abalone became infected 

with Ca.Xc when planted near an abalone farm outfall and near wild abalone populations in 

southern California, suggesting that the presence of infected abalone (farmed or wild) may pose 

similar infection risks in locations with warm ocean temperatures (Fuller 2017).

Three factors may reduce the impacts of withering syndrome on black abalone. First, researchers 

have discovered a bacteriophage that infects Ca.Xc and reduces its pathogenicity. The phage 

alters the morphology and therefore some of the functions of the pathogen (Friedman and 

Crosson 2012), such that abalone with phage-infected bacterial cells have a smaller pathogen 

load and reduced response to infection, subsequently resulting in less mortality (Friedman et al. 

2014a). There is potential for phage-therapy in wild populations but it is unknown how the phage 

is transmitted. Second, genetic resistance to withering syndrome is consistent with some 

laboratory experimental data, but has not been confirmed in wild populations (Friedman et al. 

2014a). In studies where progeny of black abalone that had and had not been previously exposed 

to the disease were then infected with the pathogen, the animals that had not been previously 

exposed had a greater pathogen load and greater mortality rate, though the difference in mortality 

was not significant (Friedman et al. 2014a). Finally, since 2003, there has been mounting 

evidence that oxytetracycline (OTC) treatments (e.g., baths, injections, or oral administration) 

are effective at removing Ca.Xc from abalone and can provide protection from reinfection for 

prolonged periods (up to several months; Friedman et al. 2007, Rosenblum et al. 2008), though 

this OTC treatment has only been applied to captive animals and not to animals in the wild 

(Friedman et al. 2003, Garcia-Esquivel et al. 2011, Moore et al. 2015). In the context of 
Black Abalone 5 - Year Status Review July 2018 | 15

potential conservation tools, it should be noted that removal of Ca.Xc by OTC treatments does 

not make the treated abalone immune to subsequent infection by the pathogen. Further research 

on withering syndrome and continued monitoring of its effects on wild populations will be 

necessary for black abalone recovery.

Other Abalone Diseases

Other abalone diseases have emerged over the past several decades, including Herpes (agent of 

ganglioneuritis), sabellidosis, infection with the protozoan parasite Perkinsus olseni, and 

vibriosis. To date, these diseases have not been observed in wild black abalone populations along 

California and Baja California. However, black abalone may be susceptible to these diseases and 

multiple pathways exist for these diseases to be introduced, such as through the movement of 

infected organisms for aquaculture, research, and hobby/food markets (see Section 2.3.2.4 

Inadequacy of existing regulatory mechanisms). Research on the effects and severity of these 

diseases to black abalone is needed, as well as consideration of preventative measures to 

minimize the risk of introducing them to the species. 

Predation

Predation is not currently considered a primary threat to black abalone. Many animals such as 

octopuses, lobsters, fishes, other gastropods, birds, and sea stars prey on abalone (Ault 1985, 

Estes and VanBlaricom 1985, Shepherd and Breen 1992). Some of these species may become a 

greater threat than others in the future depending on how each species is affected by climate 

change. For example, warmer water temperatures cause an increase in the feeding rate for the sea 

star Pisaster ochraceus and potentially other intertidal predators (Sanford 2002). However, the 

mass die-offs of sea stars beginning in 2013 due to sea star wasting disease have reduced sea star 

predation pressure, at least temporarily. Predation is an important factor for potential 

enhancement efforts such as aggregation, translocation, and outplanting. Enhancement efforts 

may need to focus on larger individuals that can better withstand predation pressure or, if 

feasible, may be aided by temporary relocation of predators from an area targeted for abalone 

restoration.

Sea otter presence is also a factor in black abalone recovery efforts. Along the central California 

coast in areas not yet affected by withering syndrome, as well as at San Nicolas Island, a positive 

correlation has been observed between sea otter and black abalone populations (Raimondi et al. 

2015; VanBlaricom 2017, unpublished data). Proposed theories to explain these observations 

include a positive relationship between: 1) sea otter presence and complex rocky habitat with 

refugia (e.g., crevices) effective in limiting otter predation on abalone; 2) both sea otters and 

black abalone with large kelp forests, given that kelp is an important habitat feature for the two

species; and 3) sea otters and kelp abundance, because sea otters prey on and control sea urchin

populations that consume kelp (Raimondi et al. 2015). Although sea otter predation is known to 

reduce the abundance of red abalone (Fanshawe et al. 2003), the relationship between sea otters 
Black Abalone 5 - Year Status Review July 2018 | 16

and black abalone is not completely understood and may change as populations of sea otters and 

black abalone increase. Factors to consider are recovery rates, population abundance, habitat 

type, and predation rate. Recovery efforts for black abalone should be closely coordinated with 

recovery efforts for sea otters. NMFS has established an agreement with the United States Fish 

and Wildlife Service (USFWS) to ensure the exchange of information and coordination of 

recovery actions for the two species (NMFS 2013 Memorandum of Understanding).

2.3.2.4 Inadequacy of existing regulatory mechanisms

Two threats of particular concern that are associated with inadequate regulatory mechanisms are 

illegal harvest and the potential introduction of pathogens and invasive species. Despite 

prohibitions on black abalone harvest in California since 1993, illegal harvest of black abalone 

continues to occur. From 1993 – 2012, most documented poaching cases occurred in San Luis 

Obispo and Monterey Counties (Taniguchi 2015, unpublished data). Thus, poaching presents a 

potentially serious risk to populations unaffected by disease and located in areas with public 

access along the central coast of California. Poaching could also increase as black abalone 

populations recover, counteracting the benefits of natural recovery or enhancement efforts. 

Regulatory measures have been established, but continued efforts to enforce the regulations, 

monitor and document poaching cases, and deter poaching (e.g., via increased penalties, 

outreach, and education) are needed. CDFW has prioritized enforcement against abalone 

poaching. Current penalties for poaching include a fine between $15,000 and $40,000, possible 

imprisonment for up to one year, and forfeiture of any licenses, equipment, and vehicles used in 

the poaching incident. CDFW has also developed a database to document poaching cases along 

the coast and evaluate the magnitude of the threat to black abalone populations (Taniguchi 2015, 

unpublished data). Revisions and additions to Southern California Marine Protected Areas under 

the CDFW Marine Life Protection Act in 2012 likely afford additional protections for black 

abalone through increased enforcement.

The introduction of pathogens or invasive species could pose a high risk to black abalone, given 

the devastating effects these diseases have had on abalone in other parts of the world. Strict 

regulations are needed to ensure adequate monitoring whenever animals are moved (e.g., 

imports, transporting between facilities) for aquaculture, research, and/or food/hobby markets, to 

protect wild populations from pathogens and invasive species. In California, state regulations and 

policies are in place that require regular abalone health monitoring at aquaculture facilities, 

control the transfer of abalone between facilities, and restrict out-planting of abalone from 

facilities that have not met certification standards. Some improvements to existing regulations 

are needed to further protect the species. For example, although a permit is required to import 

non-native abalone species for terminal markets or the aquarium trade into California, a permit is 

not needed to import native abalone species, even if the source of those abalone is outside of the 

U.S. This presents a potential risk because some abalone species native to California are cultured 
Black Abalone 5 - Year Status Review July 2018 | 17

in several locations outside of California, and because live abalone imported into the State could 

carry pathogens to which black abalone are susceptible. 

2.3.2.5 Other natural or manmade factors affecting its continued existence

Spills and Spill Response Activities

Section 2.3.2.1 discussed the potential effects of contaminant spills and spill response activities 

on the quality and quantity of black abalone habitat. Contaminant spills and spill response 

activities may also have direct effects on individual black abalone. Oil spills appear to be of 

greatest concern with regard to black abalone conservation. We have very little information on 

how different types of oil affect black abalone, although there is evidence that black abalone 

were killed in past oil spills in California and Baja California (e.g., Torch oil spill, Tampico 

Maru spill). The impact of future spills on the species’ status and recovery depends on several 

factors, including the type and amount of material spilled, the location, local environmental 

conditions, and the status of impacted populations. We cannot predict when and where spills will 

occur, but we can minimize the effects to black abalone by providing guidance on appropriate 

spill response activities, as well as providing guidance on post-monitoring efforts to learn from 

each spill and inform future response efforts. To develop this guidance, we need information on 

abalone habitat and presence throughout the coast; the effects of different types of oil and 

dispersants on abalone habitat and different life stages of abalone (e.g., survival, physiology, 

reproduction); decision-making tools for determining whether and when to collect abalone and 

bring them into captivity; methods to collect and hold animals from the wild; and methods to 

clean oiled abalone. We can also learn as much as possible from recent oil spills that affected 

black abalone and their habitat, including the Refugio oil spill in Santa Barbara County in 2015. 

Ocean Acidification

Ocean acidification is an emerging threat that is particularly concerning for larval stages, 

possibly reducing larval survival and shell growth, promoting shell abnormalities, and reducing 

the quality of larval settlement habitat by affecting the growth of crustose coralline algae (Crim 

et al. 2011, Morash and Alter 2015). However, we have limited understanding of the potential 

effects of declining ocean pH on black abalone, due to variability in local conditions throughout 

the coast, natural variation in ocean pH, species adaptability, and uncertainty in projections of 

future pH levels. Species normally exposed to varying carbon dioxide levels may be acclimatized 

to ocean acidification, with species-specific variation in the responses. North Pacific waters, 

including the California Current Ecosystem, experience fluctuations in pH, including relatively 

low seawater pH values due to a variety of natural oceanographic processes (Feely et al. 2004, 

Feely et al. 2008, Feely et al. 2009, Hauri et al. 2009). Exposure to naturally fluctuating and low 

pH may make black abalone better able to adapt to the effects of ocean acidification if, for 

example, ocean acidification increases the duration or areal extent of acidified water. However, 

we do not know how black abalone may respond to further decreases in pH levels or to other 
Black Abalone 5 - Year Status Review July 2018 | 18

effects of ocean acidification. Additional studies are needed to evaluate the potential exposure 

and response of black abalone and their habitat to ocean acidification. 

Sedimentation

Burial and subsequent re-exposure of black abalone habitat occurred in autumn 2015 on San 

Nicolas Island within a span of several months, due to an unusual oceanographic event that 

moved large amounts of sediment around the island, including an entire sand spit that 

disappeared and then re-formed (pers. comm. with Glenn VanBlaricom, USGS/UW, on 23 Mar 

2016, and with John Ugoretz, Navy/CDFW, on 25 May 2016). The event resulted in apparently 

precipitous mortalities of black abalone and many other intertidal plant and animal species. How 

that system recovers from this impact may provide insight to other areas of coastal California. As 

mentioned in Section 2.3.2.1 (Present or threatened destruction, modification, or curtailment of 

its habitat or range), a large landslide occurred along the Big Sur coast in May 2017, burying a 

segment of the coast in sediment. Sedimentation from continued erosion of the landslide has 

buried black abalone and black abalone habitat adjacent to the landslide (Raimondi et al. 2017), 

calling for emergency actions to minimize and monitor impacts to black abalone. 

Environmental Pollutants and Toxins

We know of three cases where environmental pollutants and toxins directly affected the health 

and survival of black abalone. First, on the Palos Verdes Peninsula in the late 1950s and early 

1960s, black abalone growth and reproduction declined due to poor water quality, resulting from 

the combined effects of a significant El Niño event and large-volume domestic sewage discharge 

by Los Angeles County (Leighton 1959, Cox 1962, Miller and Lawrenz-Miller 1993). Second, 

Martin et al. (1977) documented black abalone mortalities in Diablo Cove in the 1970s, resulting 

from the local power plant’s release of effluent containing toxic levels of copper. Third, the 

grounding of the S/V Blue Mist near Pt. Piedras Blancas in northern San Luis Obispo County, 

and subsequent release of ballast shrapnel, led to the loss of at least one abalone, and possibly 

more (Lonhart et al. 2015). In most cases, the effects of the factors noted here were limited in 

temporal and/or geographic scope. 

Larval Entrainment

Larval entrainment likely poses a low risk to recovery, given the low number of intakes (e.g., at 

power plants, desalination plants) along the coast and the small area affected (likely limited to 

the area directly around the intake). Intakes and outfalls can lead to larval impingement, 

entrainment, and shear stress, all of which could physically kill larvae. Therefore, future 

development or expansion of power plants or other major coastal-dependent industrial facilities 

should consider black abalone habitat when determining where to place intakes and outfalls to 

limit potential impacts.
Black Abalone 5 - Year Status Review July 2018 | 19

2.4 Synthesis

The black abalone was listed as endangered in 2009 (74 FR 1937, 14 January 2009). Even prior 

to the listing, researchers and managers throughout California have been collaborating to monitor 

the status of black abalone populations in the wild. Long-term monitoring has been conducted 

throughout the coast, in some areas since the mid-1970s, providing valuable data to assess 

population trends over time. Based on these data, researchers were able to detect the severe 

declines in black abalone populations throughout southern California in the 1980s and 1990s, 

caused by the disease called withering syndrome. The disease contributed significantly to the 

species’ extinction risk and was identified as the primary threat to the species in the 2009 Status 

Review (VanBlaricom et al. 2009). 

Since the listing, NMFS has continued to work with partners throughout the coast on black 

abalone conservation and research. Partners include other Federal, State, local, and international 

agencies; universities and other research institutions; public aquaria; and non-profit 

organizations. Long-term monitoring continues throughout the California coast and has 

expanded to encompass additional sites, including potential sites in Baja California. Diseaseimpacted populations in southern California remain at low densities; in most areas, densities are 

below the estimated minimum adult density needed to support successful reproduction and 

recruitment. However, recent recruitment and increases in abundance have been observed at 

several locations throughout southern California and Baja California. These observations 

indicate that factors other than the density of abalone need to be considered when assessing 

population viability. For example, the tendency of black abalone to aggregate likely increases 

fertilization success in wild populations. Long-term monitoring and experimental studies are 

ongoing to improve our understanding of population dynamics and evaluate different tools to 

enhance population restoration (i.e., habitat restoration, local aggregation, translocation, captive 

breeding and outplanting), where needed. 

Withering syndrome remains a primary threat to the species. The disease has progressed 

northward along the coast with sea-surface warming events, with disease-related declines 

observed in populations as far north as the Monterey/San Luis Obispo County line (Miner 2017, 

unpublished data). Healthy populations remain to the north, but have been exposed to the 

pathogen and therefore are at risk of withering syndrome. However, two factors may ameliorate 

the impacts of the disease on black abalone in the wild: the presence of a bacteriophage that 

infects the pathogen, reducing its pathogenicity and increasing the survival rate of infected 

abalone (Friedman and Crosson 2012, Crosson et al. 2014, Friedman et al. 2014a, b); and the 

potential for genetically-based disease resistance (VanBlaricom et al. 2009, Friedman et al. 

2014a). Both are the subject of ongoing studies. In addition, studies on captive populations

indicate that use of antibiotic (oxytetracycline) treatment can effectively remove the pathogen 

from abalone, which will be important as population restoration tools such as captive 

propagation continue to develop. 
Black Abalone 5 - Year Status Review July 2018 | 20

Other threats of particular concern include other abalone diseases, poaching, contaminant spills 

and their response activities, and potential impacts from ocean acidification and elevated water 

temperatures. Research on withering syndrome has advanced significantly over the past few 

years, but additional studies are needed to evaluate the susceptibility of black abalone to known 

and emerging abalone diseases worldwide. Regulations are in place to minimize the introduction 

and spread of these diseases to wild black abalone populations; however, enforcement and 

monitoring are needed. Black abalone harvest prohibitions have been established throughout the 

species’ range, but further effort is needed to assess the level of poaching and its impacts on 

black abalone. Contaminant spills and their associated response activities pose a threat to black 

abalone throughout the coast. Plans are in development to guide response activities in the event 

of a spill, to minimize and monitor impacts to black abalone and their habitat. Ocean 

acidification is an emerging threat to black abalone and many calcifying organisms, and further 

studies are needed to evaluate the potential effects on the species’ status and recovery. Elevated 

water temperatures can accelerate the transmission of withering syndrome and disease-related 

mortality; however, further study and monitoring are needed, given the potential for the 

bacteriophage and genetically-based disease resistance to improve survival despite increased 

water temperatures.

Overall, ongoing long-term monitoring and research continue to provide valuable information to 

inform our understanding of the species’ status and threats throughout the coast. Black abalone 

populations in southern California that have been severely impacted by withering syndrome 

remain at low densities, with signs of recruitment and increasing numbers at a few localized 

sites. Healthy populations in central California that have not yet been affected by the disease 

remain at risk to withering syndrome, although the bacteriophage and genetically-based 

resistance could reduce the severity of the impacts. Other threats contribute to the species’ high 

extinction risk, including other abalone diseases, poaching, contaminant spills and their response 

activities, and ocean acidification. Considering the status and continuing threats, black abalone 

remain in danger of extinction. Therefore, the recommended classification for black abalone is to 

remain the same: Endangered.
Black Abalone 5 - Year Status Review July 2018 | 21

3.0 RESULTS

3.1. Recommended Classification

____ Downlist to Threatened

____ Uplist to Endangered

____ Delist

____ Extinction

____ Recovery

____ Original data for classification in error

_X_ No change is needed

3.2. New Recovery Priority Number 

Brief Rationale: No change to the Recovery Priority Number is recommended at this 

time for black abalone. A Recovery Priority Number of 5 remains appropriate for black

abalone because the species has a moderate extinction risk and a high potential for 

recovery, based on the 1990 Recovery Priority Guidelines (55 FR 24296, 15 June 1990).

The status of black abalone remains largely the same as it was at the time of the listing, 

with a few improvements, such as reduced disease impacts (due to the bacteriophage and 

potential genetically-based disease resistance) and signs of recruitment and increasing 

numbers at a few southern California sites. Recovery will involve efforts to enhance the 

viability and the resiliency of black abalone populations and to monitor and manage

potential disease risks. 

4.0. RECOMMENDATIONS FOR FUTURE ACTIONS

The Recovery Plan for black abalone is expected to be available before the next five-year status 

review update. Finalizing the Recovery Plan and implementing priority recovery actions are 

primary future action recommendations. Other actions that would improve the status of and 

available information about black abalone include the following: 

1. Continue and/or expand long-term monitoring programs to evaluate population trends 

over time throughout the species’ range. Monitoring should include density, recruitment 

patterns, size structure, spatial structure (e.g., nearest neighbor), growth rates, sex ratios, 

health observations, and habitat characteristics. Establishment of regular monitoring sites 

in Baja California and exploration of subtidal monitoring is needed. NMFS should 

continue to collaborate with partners throughout the coast to maintain, expand, and/or 

refine monitoring efforts and coordinate management, analysis, and sharing of the data. 
Black Abalone 5 - Year Status Review July 2018 | 22

2. Evaluate genetic structure and diversity of wild black abalone populations across local 

and broad spatial scales. Understanding the genetic structure and diversity of black 

abalone will inform our understanding of population dynamics and implementation of 

population restoration actions, such as translocation, captive breeding, and outplanting. 

We need to inventory existing genetic samples and analysis results, as well develop and 

implement genetic sampling to assess population structure.

3. Evaluate population restoration methods to enhance populations. Studies are needed to 

evaluate the value and efficacy of population restoration methods such as habitat 

restoration, local aggregation, translocation, and captive propagation and outplanting. 

Pilot habitat restoration studies are proposed for sites in California (NMFS 2016b). 

Limited studies on local aggregation and translocation have been conducted (Ruediger 

1999); key questions include methods to minimize the risk of injury/mortality when 

moving animals, and what spatial scale and number of animals constitutes an effective 

aggregation for population enhancement. Research is ongoing to develop reliable captive 

breeding techniques for black abalone (NMFS 2016a), which have proven difficult to 

spawn in captivity. The ability to captively breed black abalone would provide another 

tool for population restoration and another source of animals for use in laboratory studies. 

4. Improve tracking of poaching cases and violations. CDFW has an existing database to 

track poaching cases in California; however, additional information is needed, such as 

identification of the species taken, the number of abalone taken, and the condition/status 

and disposition of the abalone. Guidance is needed on the disposition of dead and live 

black abalone confiscated during poaching cases. For example, live animals may be 

returned to the wild or brought into a captive facility for use in research. Coordinated 

efforts to enforce regulations should continue and additional actions to further deter 

poaching (e.g., increased penalties, outreach, and education) should be considered.

5. Continue, refine, and expand research on withering syndrome and other abalone 

diseases. Additional studies on withering syndrome are needed to inform our 

understanding and how to advance the species’ recovery in the presence of this disease. 

Important research topics include: transmission dynamics, factors affecting susceptibility 

to infection and onset of disease, phage distribution and dynamics, genetic disease 

resistance, and effects of infection on fitness. Studies are also needed to evaluate the 

species’ susceptibility to other abalone diseases, including diagnosing and understanding 

host-parasite relationships. In addition to disease research, existing regulations for live 

trade of abalone and other marine species should be reviewed and revised as needed to 

minimize the risk of transmitting pathogens.
Black Abalone 5 - Year Status Review July 2018 | 23

6. Develop interim plan for pre-emptive or non-preemptive removal of black abalone from 

the wild in response to events such as oil spills and vessel groundings. A plan is needed 

to guide consideration of whether to remove animals from the wild and bring them into 

captivity in the event of an emergency, such as a catastrophic oil spill. This plan should 

provide decision-making tools and guidance; protocols for abalone care, cleaning, and 

holding over the short and long-term; a list of potential captive holding facilities; and 

guidance for returning animals to the wild. 

7. Evaluate pH tolerance and the effects of decreasing pH on various life stages of black 

abalone. Studies are needed to evaluate the effects of decreasing pH on the development, 

survival, growth, and condition of different life stages of black abalone. Early life stages 

of abalone may be most susceptible to reduced pH levels. Results of these studies would 

inform our understanding of the threat of ocean acidification to black abalone and the 

development of measures to address this threat. 

8. Maintain and enhance coordination with Mexico on abalone conservation. 

Communication and collaboration among abalone researchers in the U.S. and Mexico 

have increased in recent years. Opportunities to meet and exchange information on a 

regular basis should be sought or developed, for example, through annual or biennial 

workshops. Further collaborations should also be pursued on topics of shared interest, 

such as genetic, disease, and captive breeding research, and long-term monitoring.

9. Develop key, unified messaging in collaboration with outreach and education partners. 

Identification of key, unified messaging will be important to ensure a consistent message 

is relayed by the many partners involved in black abalone conservation. Outreach and 

education will involve development of signage and educational materials for use at 

facilities and in social media, as well as incorporation of key messaging into existing 

programs (e.g., K-12 school programs, docent training programs, citizen science groups 

working in the rocky intertidal).
Black Abalone 5 - Year Status Review July 2018 | 24

5.0 REFERENCES

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76 FR 66806. U.S. Federal Register, Volume 76, No. 208, Page 66806. October 27, 2011. 

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impair larval development and reduce larval survival in endangered northern abalone 

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Cox, K. W. 1962. California abalones, family haliotidae. California Department of Fish and 

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Crosson, L. M., N. Wight, G. R. VanBlaricom, I. Kiryu, J. D. Moore, and C. S. Friedman. 2014. 

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Crosson, L.M., N.S. Lottsfeldt, M.E. Weavil-Abueg, and C.S. Friedman. In manuscript. Abalone 

withering syndrome disease dynamics: Pathogen stability and infectious dose. 

del Rio Portilla, Miguel and Fabiola Lafarga de la Cruz. CICESE. 20 July 2017. Personal 

communication, via email to Susan Wang (NMFS), regarding abalone fishery regulations in 

Mexico.

Duncan, E.A. 2017. Environmental controls of black abalone body temperature determine risks 

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ll I ,I , · k .\ b a I 1.1 11 c' .; - Y ,· ;1 I \ l ,1 l ll •; R L' \ I ,· \\ \I a \ ' 0 I 8 I 

NATIONAL MARINE FISHERIES SERVICE 

5-YEAR REVIEW 

Black Abalone (Haliotis cracherodi1) 

Current Classification: I:ndangcred 

Recommendation resulting from the 5-Year Review 

Downlist to Threatened 

__ Uplist to Endangered 

Dclist 

_X_ No change is needed 

Review Conducted By: NMFS West Coast Region. Protected Resources Division 

REGIONAL OFFICE APPROVAL: 

HEADQUARTERS APPROVAL: 

Assistant Administrator, NMFS 

~ r Do Not Concur 

Signature _ ~ Date: /~IO[f?'