Seafood Watch Seafood Report

Seafood Watch Seafood Report Mexican Sea Scallops Nodipecten subnodosus (Image courtesy of Stephanie Dancer) Laguna Ojo de Liebre and Guerrero Negro, Baja California Sur (Mexico) January 3, 2011 Annie J. Yau Consulting Researcher

About Seafood Watch and the Seafood Reports Monterey Bay Aquarium s Seafood Watch program evaluates the ecological sustainability of wild-caught and farmed seafood commonly found in the United States marketplace. Seafood Watch defines sustainable seafood as originating from sources, whether wild-caught or farmed, which can maintain or increase production in the long-term without jeopardizing the structure or function of affected ecosystems. Seafood Watch makes its science-based recommendations available to the public in the form of regional pocket guides that can be downloaded from www.seafoodwatch.org. The program s goals are to raise awareness of important ocean conservation issues and empower seafood consumers and businesses to make choices for healthy oceans. Each sustainability recommendation on the regional pocket guides is supported by a Seafood Report. Each report synthesizes and analyzes the most current ecological, fisheries and ecosystem science on a species, then evaluates this information against the program s conservation ethic to arrive at a recommendation of Best Choices, Good Alternatives or Avoid. The detailed evaluation methodology is available upon request. In producing the Seafood Reports, Seafood Watch seeks out research published in academic, peer-reviewed journals whenever possible. Other sources of information include government technical publications, fishery management plans and supporting documents, and other scientific reviews of ecological sustainability. Seafood Watch Research Analysts also communicate regularly with ecologists, fisheries and aquaculture scientists, and members of industry and conservation organizations when evaluating fisheries and aquaculture practices. Capture fisheries and aquaculture practices are highly dynamic; as the scientific information on each species changes, Seafood Watch s sustainability recommendations and the underlying Seafood Reports will be updated to reflect these changes. Parties interested in capture fisheries, aquaculture practices and the sustainability of ocean ecosystems are welcome to use Seafood Reports in any way they find useful. For more information about Seafood Watch and Seafood Reports, please contact the Seafood Watch program at Monterey Bay Aquarium by calling 1-877-229-9990. Disclaimer Seafood Watch strives to have all Seafood Reports reviewed for accuracy and completeness by external scientists with expertise in ecology, fisheries science and aquaculture. Scientific review, however, does not constitute an endorsement of the Seafood Watch program or its recommendations on the part of the reviewing scientists. Seafood Watch is solely responsible for the conclusions reached in this report. Seafood Watch and Seafood Reports are made possible through a grant from the David and Lucile Packard Foundation. 1

Table of Contents I. Executive Summary...5 II. Introduction...8 III. Analysis of Seafood Watch Sustainability Criteria for Wild-caught Species...23 Criterion 1: Inherent Vulnerability to Fishing Pressure...23 Criterion 2: Status of Wild Stocks...30 Criterion 3: Nature and Extent of Bycatch...36 Criterion 4: Effect of Fishing Practices on Habitats and Ecosystems...41 Criterion 5: Effectiveness of the Management Regime...46 IV. Overall Evaluation and Seafood Recommendation...53 V. References...56 2

Capture Fisheries Evaluation Species: Nodipecten subnodosus Region: Laguna Ojo de Liebre, Baja California Sur (Mexico) Analyst: Annie J. Yau Date: January 3, 2011 Seafood Watch defines sustainable seafood as originating from sources, whether fished 1 or farmed, that can maintain or increase production in the long-term without jeopardizing the structure or function of affected ecosystems. The following guiding principles illustrate the qualities that capture fisheries must possess to be considered sustainable by the Seafood Watch program. Species from sustainable capture fisheries: have a low vulnerability to fishing pressure, and hence a low probability of being overfished, because of their inherent life history characteristics; have stock structure and abundance sufficient to maintain or enhance long-term fishery productivity; are captured using techniques that minimize the catch of unwanted and/or unmarketable species; are captured in ways that maintain natural functional relationships among species in the ecosystem, conserves the diversity and productivity of the surrounding ecosystem, and do not result in irreversible ecosystem state changes; and have a management regime that implements and enforces all local, national and international laws and utilizes a precautionary approach to ensure the long-term productivity of the resource and integrity of the ecosystem. Seafood Watch has developed a set of five sustainability criteria, corresponding to these guiding principles, to evaluate capture fisheries for the purpose of developing a seafood recommendation for consumers and businesses. These criteria are: 1. Inherent vulnerability to fishing pressure 2. Status of wild stocks 3. Nature and extent of discarded bycatch 4. Effect of fishing practices on habitats and ecosystems 5. Effectiveness of the management regime 1 Fish is used throughout this document to refer to finfish, shellfish and other wild-caught invertebrates. 3

Each criterion includes: Primary factors to evaluate and rank Secondary factors to evaluate and rank Evaluation guidelines 2 to synthesize these factors A resulting rank for that criterion Once a rank has been assigned to each criterion, an overall seafood recommendation for the species in question is developed based on additional evaluation guidelines. The ranks for each criterion, and the resulting overall seafood recommendation, are summarized in a table. Criterion ranks and the overall seafood recommendation are color-coded to correspond to the categories of the Seafood Watch pocket guide: Best Choices/Green: Consumers are strongly encouraged to purchase seafood in this category. The wild-caught species is sustainable as defined by Seafood Watch. Good Alternatives/Yellow: Consumers are encouraged to purchase seafood in this category, as they are better choices than seafood in the Avoid category. However there are some concerns with how this species is fished and thus it does not demonstrate all of the qualities of a sustainable fishery as defined by Seafood Watch. Avoid/Red: Consumers are encouraged to avoid seafood in this category, at least for now. Species in this category do not demonstrate enough qualities to be defined as sustainable by Seafood Watch. 2 Evaluation Guidelines throughout this document reflect common combinations of primary and secondary factors that result in a given level of conservation concern. Not all possible combinations are shown other combinations should be matched as closely as possible to the existing guidelines. 4

I. Executive Summary Mexican Sea scallops, also known as Lion s Paw scallops (Nodipecten subnodosus) reside in the North Pacific and South Pacific oceans, ranging from the Baja California Peninsula in Mexico south to Peru. Along both coasts of the Baja California Peninsula, these scallops are harvested by divers. Although the intrinsic rate of population increase is unknown, other life history characteristics of the Mexican Sea scallop have been well studied. These scallops have fast growth rates, a short time to maturity (less than one year), high reproductive output, and a broad species range. The habitat of this species in Laguna Ojo de Liebre and Guerrero Negro is moderately altered by domestic, industrial, and agricultural runoff. Overall, the biology of this species results in Seafood Watch deeming it to be inherently resilient to fishing pressure. The Mexican Sea scallop fishery is considered to be at optimum exploitation. The value of B MSY is unknown, but the National Fisheries Institute considered maximum production level had not yet been reached in 2000 despite the overall increase in production since the fishery began in 1991. Although F MSY is also unknown, F curr is 20 30% of the total biomass of legal-sized clams. There is a moderate degree of uncertainty in the status of the stock because, even though data from annual fishery-independent stock assessments and landings records are available, data from the most recent years are unobtainable. Data on biomass landings are not standardized according to effort, and catch-per-unit-effort (CPUE) data are not available for this fishery. Long-term population abundance is variable while the short-term trend is arguably flat and slightly variable. The current biomass distribution of the stock is approximately normal (bell-shaped) and not skewed, with legal-sized clams still relatively abundant as of 2000. The stock status of Mexican Sea scallops is deemed by Seafood Watch to be a moderate conservation concern because the fishery is considered to be at optimum exploitation, B MSY and F MSY are unknown, and the overall trend in population abundance is flat and/or variable. The quantity of bycatch from the diver-caught Mexican Sea scallop fishery is minimal as a result of the extraction practice of individually hand removing scallops by divers working from small boats with outboard motors and breathing-air compressors. As a result, the bycatch effects on the population and ecosystem should also be minimal, although direct studies assessing these impacts have not been conducted. The nature and extent of discarded bycatch in the Mexican Sea scallop fishery is considered a low conservation concern. The shallow mud and sandy bottom habitats of Mexican Sea scallops are moderately resilient, but the Mexican Sea scallop fishery causes minimal habitat damage due to the nature of the extraction method: hand removal of individual scallops by divers. The ecosystem impacts of the removal of Mexican Sea scallops by the commercial fishery are unknown; however, these impacts are likely low as the fishery causes minimal habitat damage. The food web impacts of removing Mexican Sea scallops are unknown. Because the habitat damage and ecosystem impacts are likely low, Seafood Watch considers the Mexican Bay scallop diver-caught fishery to be a low conservation concern for effects on habitats and ecosystems. 5

Annual stock assessments are conducted by the Regional Fishery Center of La Paz for Mexican Sea scallops; the results of these assessments are used to set annual quotas. Landings data are also collected from permit holders and reported annually. Data on annual quotas were not obtainable, making it impossible to evaluate whether management has exceeded its standard of allowing 20 30% of the biomass of legal-sized clams to be harvested. Based on landings data, however, annual harvest has never exceeded 20% of the total estimated biomass (biomass could not be separated into legal-sized versus illegal-sized clams). Due to the low-impact nature of the extraction method (hand harvesting of individual scallops by divers), no management action regarding bycatch or ecosystem status is needed. The enforcement status of these regulations is unknown, but permit holders are required to report their daily catch in logbooks. Management has maintained stock productivity over time with overall increasing trends in landings. The annual evaluation of the fishery consisting of stock assessments, quotas, and landings records results in a management regime effectiveness score of highly effective. Due to the low conservation concern of four out of five criteria as well as the moderate conservation concern for the stock status, the diver-caught Mexican Sea scallop fishery in Laguna Ojo de Liebre and Guerrero Negro, Baja California Sur, Mexico, is ranked a Best Choice by Seafood Watch. Table of Sustainability Ranks Conservation Concern Sustainability Criteria Low Moderate High Critical Inherent Vulnerability Status of Stocks Nature of Bycatch Habitat & Ecosystem Effects Management Effectiveness 6

About the Overall Seafood Recommendation: A seafood product is ranked Best Choice if three or more criteria are of Low Conservation Concern (green) and the remaining criteria are not of High or Critical Conservation Concern. A seafood product is ranked Good Alternative if the five criteria average to yellow (Moderate Conservation Concern) OR if the Status of Stocks and Management Effectiveness criteria are both of Moderate Conservation Concern. A seafood product is ranked Avoid if two or more criteria are of High Conservation Concern (red) OR if one or more criteria are of Critical Conservation Concern (black) in the table above. Overall Seafood Recommendation: Best Choice Good Alternative Avoid 7

II. Introduction Also known as the Lion s Paw scallop ( la almeja mano de león ), the Mexican Sea scallop, Nodipecten subnodosus (formerly Lyropecten subnodosus) is a fast growing scallop of the family Pectinidae that can reach sizes of 175 mm or more in length (Félix- Pico 2006) up to a maximum of 218 mm (Ponce-Díaz et al. in press). Mexican Sea scallops generally reach 60 80 mm in one year (Barrios-Ruiz et al. 2003). At the average adult size of 175 mm, total weight is 1,400 g and the adductor muscle (the edible part) weighs 160 g (Félix-Pico 2006). The shell color ranges from white with purple lines or dull purple to bright orange and magenta (Félix-Pico 2006). The species is a functional hermaphrodite with spawning occurring annually between September and November (Morales-Hernandez and Caceres-Martinez 1996, Arellano-Martinez et al. 2004, Taylor et al. 2006, Petersen et al. 2008). The Mexican Sea scallop can be found along both coasts of the Baja California Peninsula (both the Pacific and Gulf of California coasts) in Mexico south to Peru (Barrios-Ruiz et al. 2003, Koch et al. 2005, Félix-Pico 2006). The depth of these scallops ranges from 6 35 m deep in the bays where they are harvested and up to 150 m in the open ocean (Félix-Pico 2006). The main fishing grounds for the Mexican Sea scallops are in Laguna de Ojo de Liebre and to a lesser extent Laguna Guerrero Negro, and Laguna Manuela (Fig. 1) (Morales-Hernandez and Caceres-Martinez 1996, Masso-Rojas et al., Koch et al. 2005, Beltrán-Lugo et al. 2006, Félix-Pico 2006, Maldonado 2010). These three contiguous lagoons on the Pacific coast of Baja California Sur are known as complejo lagunar Ojo de Liebre and serve as the main fishing grounds because the abundance of Mexican Sea scallops is very low elsewhere (Morales-Hernandez and Caceres-Martinez 1996, Masso-Rojas et al. 2000). The National Fisheries Institute (Instituto Nacional de Pesca, or INAPESCA) lists the general area of Laguna Ojo de Liebre as the only fishing ground recognized as currently open (Masso-Rojas et al. 2000). The fishing grounds of Laguna Ojo de Liebre and Guerrero Negro are located within the Vizcaíno Biosphere Reserve, which has regulations on the use of natural resources within its boundaries. 8

Figure 1. Map of the complete lagunar region of Ojo de Liebre on the west coast of Baja California showing the contiguous lagoons of Laguna Ojo de Liebre (the main fishing ground), Laguna Guerrero Negro, and Laguna Manuela, all within the Vizcaíno Biosphere Reserve. There is no federal law regulating the harvest of Mexican Sea scallops (Morales-Hernandez and Caceres-Martinez 1996, Masso-Rojas et al. 2000). This fishery is managed by the National Fisheries and Aquaculture Commission (Comisión Nacional de Pesca y Acuacultura, CONAPESCA) in coordination with the Secretary of Environment and Natural Resources (la Secretaria del Medio Ambiente y Recursos Naturales, SEMARNAT) because of the location of the fishing grounds within the Vizcaino Biosphere Reserve. 9

These two organizations, CONAPESCA and SEMARNAT, set total quotas and the number of permits based on surveys and stock assessments completed by the Regional Fishery Center of La Paz (Centro Regional de Investigación Pesquera, CRIP), which is part of the National Fisheries Institute (Instituto Nacional de Pesca, INAPESCA) (Morales-Hernandez and Caceres-Martinez 1996, Masso- Rojas et al. 2000, Félix-Pico 2006, Ponce-Díaz et al. in press). Stock assessments are conducted annually by CRIP in order to determine the annual harvest quota of 20 30% of the biomass of legalsized clams (see below). (Morales-Hernandez and Caceres-Martinez 1996, Masso-Rojas et al. 2000, Félix-Pico 2006, Ponce-Díaz et al. in press). Between 9 and 15 of the 18 designated scallop banks within the fishery area are sampled every year. Divers collect scallops every 200 250 m along each bank, sampling a randomly selected 10 m 2 area at each interval. The length, total weight, and adductor muscle weight of individual scallops are measured and the size/mass distributions, abundance and density, and total adductor muscle biomass are determined using this data; detailed methods are available (see Masso-Rojas et al. 2000, Ponce-Díaz et al. in press). From 1996 2004, abundance and adductor muscle biomass estimated from stock assessments followed a similar trend, with a peak in biomass of 1,600 tonnes in 1998 followed by a small decline and then a flat and slightly variable trend from 2000 2004 (Fig. 2) (Ponce-Díaz et al. in press). Stock assessments have also indicated a temporally consistent size distribution, with no indication of truncation due to size-selective harvest; adductor muscle biomass peaks at 14 15 cm long and overall biomass increased annually to a peak in 1999 (Fig. 3) (Masso-Rojas et al. 2000). 10

Figure 2. Stock assessment estimates for the Mexican Sea scallop, Nodipecten subnodosus, from Laguna Ojo de Liebre from 1996 2004. Top: abundance (# of organisms) each year. Bottom: total estimated adductor muscle biomass (tonnes). Abundance and biomass follow similar trends with a peak in 1998 followed by a small decline and a relatively flat trend from 1999 2004 (figure from Ponce-Díaz et al. in press). 11

Figure 3. Adductor muscle biomass distributions (tonnes) for Mexican Sea scallops (Nodipecten subnodosus) from 1996 2000 in Laguna Ojo de Liebre, Baja California Sur. Biomass consistently peaks at ~14 15 cm long, and overall population biomass increases annually with a peak in 1999. Data from stock assessments conducted by the National Fisheries Institute (figure from Masso-Rojas et al. 2000). There is a discrepancy between the peak in adductor muscle biomass from this figure and from Figure 2, which indicates a peak in adductor muscle biomass in 1998; the reason for this discrepancy is unknown. 12

Based on the reproductive cycle, an open season is designated from May to August as well as in December after an annual closure from September 15 December 15 that allows the scallops to spawn (Ponce-Díaz et al. 2009). The minimum size limit is currently 140 mm shell length, down from the previous 150 mm shell length limit (Masso-Rojas et al. 2000, Ponce-Díaz et al. in press). Since 1996, the fishery management goal has been to maintain an exploitation rate of 20 30% of the biomass from legal-sized clams (Masso-Rojas et al. 2000, Ponce-Díaz et al. in press). The Mexican Sea scallop fishery of Laguna Ojo de Liebre and Guerrero Negro is considered by fishery management to be at optimum exploitation with no danger of overexploitation (Morales-Hernandez and Caceres-Martinez 1996, Masso-Rojas et al. 2000, Ponce-Díaz et al. 2009). Permits are non-transferable, geographically specific, and specify the total catch per boat (with a limit of one diver per boat), the minimum size limit, and the permit expiration date (Morales-Hernandez and Caceres-Martinez 1996). The catch quota is set at 300 to 400 clams per diver per day, and each fishing license covers two divers (for individual licenses) or up to 6 divers (for cooperative licenses) (Ponce-Díaz et al. in press). This quota represents about 1 2 tonnes of adductor muscle biomass per license per year (Félix- Pico 2006). The establishment of mandatory rotating banks is recommended (SAGARPA 2004, Ponce-Díaz et al. 2009). Permits are available only to local residents of the region, usually from the nearby town of Guerrero Negro, as the fishery is located within the Vizcaino Biosphere Reserve, which mandates the use of natural resources be preferentially offered to local residents (Masso-Rojas et al. 2000). Data on these annual quotas and the number of permits issued for the short period from 1991 1995 are available (Fig. 4) (Morales-Hernandez and Caceres-Martinez 1996). In 2009, there were 27 individual licenses and 7 fishing cooperative licenses covering ~96 vessels; 30 44 fishing licenses are allowed from year to year (Ponce-Díaz et al. 2009, Ponce-Díaz et al. in press). 13

Figure 4. Number of permits (white), number of active boats (gray), and tons of adductor muscle (black) for the Mexican Sea scallop fishery in Laguna Ojo de Liebre, Baja California Sur from 1991 1995. The units of active equipment are unclear and most likely refer to the number of boats, with one diver per boat (figure from Morales-Hernandez and Caceres-Martinez 1996). Mexican Sea scallops are individually hand harvested by divers operating from small boats of (at most) 7 m in length equipped with outboard motors and semi-autonomous compressors to supply air for one diver (also referred to as hookah diving ). Dredging has never been used (Morales-Hernandez and Caceres-Martinez 1996, Masso-Rojas et al. 2000, SAGARPA 2004, Koch et al. 2005, Félix- Pico 2006, Ponce-Díaz et al. in press). Each boat is limited to one diver but generally also carries a driver and another crew member who remain on the boat to operate the compressor (Ponce-Díaz et al. in press). The enforcement status of this fishery is unknown, but permit holders are required to report their daily catch (in number of scallops) in logbooks. Documentation suggests to the existence of monitoring and enforcement activities (see Ponce-Díaz et al. 2009). Because 14

this fishery is managed through a permit process that establishes individual quotas per permit, there may be bias in the landings data as most fishermen report landings extremely close to their quota values (Ponce-Díaz et al. in press). Small amounts of commercial landings of this scallop started in the 1970s, although landings data specific to this fishery only begin in 1991. The National Fisheries Institute (Instituto Nacional de Pesca, INAPESCA) considers the commercial fishery to have been officially opened in 1991 (Masso-Rojas et al.). Landings data specific to Mexican Sea scallops are available for the time period from 1991 2007 (Morales-Hernandez and Caceres-Martinez 1996, Masso-Rojas et al. 2000, Ponce-Díaz et al. 2009, Ponce-Díaz et al. in press). Prior to 1991, production was so low that landings of this scallop were included with several other species (Ponce-Díaz et al. in press). In the first year for which landings data are available for this fishery, 1991, production was extremely low (5 tonnes of adductor muscle). Production peaked in 2007 at 255 tonnes of adductor muscle meat, with a smaller peak in 1999 at 157 tonnes (Figs. 5, 6) (Masso-Rojas et al. 2000, Barrios-Ruiz et al. 2003, Ponce-Díaz et al. 2009). Since 2001, landings have been increasing (Fig. 6) (Ponce-Díaz et al. 2009). Scallop fisheries in general are notoriously variable, going through boom and bust phases (Maeda-Martínez et al. 1993, Félix-Pico 2006), so large fluctuations in abundance are not unusual. Variability in the abundance of harvested scallops may be due to environmental variability and/or a strong stock-recruitment relationship (Smith and Rago 2004). Data from 1991 1995 separating the landings data by sector (individual versus cooperative) suggest that most of the catch is harvested by individual licensees (Fig. 7) (Morales-Hernandez and Caceres-Martinez 1996). Landings data standardized by effort are extremely rare; some catch-per-unit-effort (CPUE) data for Mexican Sea scallops exists for 1991 1995, but the units of effort are unclear (Fig. 8) (Morales- Hernandez and Caceres-Martinez 1996). 15

Figure 5. Annual harvest (tonnes of adductor muscle) of Mexican Sea scallops, Nodipecten subnodosus, from Laguna Ojo de Liebre, Baja California Sur (figure from Ponce-Díaz et al. in press). 16

Figure 6. Total weight (tonnes) of Mexican Sea scallop (Nodipecten subnodosus) captured from the fishery in Laguna Ojo de Liebre, Baja California Sur (figure from Ponce-Díaz et al. 2009). 17

Figure 7. Tonnes of harvested adductor muscle from Mexican Sea scallops (Nodipecten subnodosus) in Laguna Ojo de Liebre, Baja California Sur from 1991 1995 separated into individuals ( Sector Privado ) and fishermen cooperatives ( Sector Social ) (figure from Morales-Hernandez and Caceres-Martinez 1996). 18

Figure 8. Catch per unit effort (CPUE): adductor weight (tonnes) of Mexican Sea scallops harvested from Laguna Ojo de Liebre, Baja California Sur, standardized to effort. Effort units are unclear, and the value from 1992 is estimated (figure from Morales-Hernandez and Caceres-Martinez 1996). Reports of landings data for this species from sources outside of Baja California Sur are often combined with other scallops and bivalves, especially prior to 1991. A national annual report, the Mexican Annual Fishery Statistics Report, includes landings of almejas (clams) that generally lump together all bivalves including scallops, arks, clams, and pens (SAGARPA 2004, Félix-Pico 2006, SAGARPA 2008) (Fig. 9). The Mexican Sea scallop is the second most important scallop to the overall scallop fishery in Mexico in terms of weight landed, preceded by the Mexican Bay scallop (Argopecten ventricosus); harvest of Mexican Sea scallops accounted for roughly 11% of the total scallop live weight caught from 1986 2001, with most of the nation s scallop harvest coming from Baja California Sur (Fig. 9) (SAGARPA 2004, Félix-Pico 2006). Mexican Sea scallops accounted for 3% of almeja weight from 1998 2000 (Masso-Rojas et al. 2000). In 2008, 20,948 tonnes by live weight of bivalves ( almejas ) were harvested in Baja California Sur, totaling 74% of all bivalves harvested in Mexico (SAGARPA 2008). None of the data provided in the Mexican Annual Fishery Statistics Report were standardized according to effort. 19

The majority of Mexican Sea scallops are processed immediately after harvest aboard the fishing vessel or in nearby residences or in other air-conditioned rooms. Due to the small scale of this fishery, there are no processing factories near the fishing grounds. A small, local factory produces ice and offers a cold room for scallop processing. Adductor muscle meat is extracted and stored on ice in trucks before being driven to distribution centers. Buyers also come directly to the town of Guerrero Negro, adjacent to the fishing grounds, to purchase muscle meat (Masso-Rojas et al. 2000, Ponce-Díaz et al. in press). Adductor muscle is refrigerated for local consumption in La Paz, Los Cabos, Ensenada, Tijuana, and Mexico City within Mexico, and is also exported to the United States as a frozen product (Morales-Hernandez and Caceres-Martinez 1996, Masso-Rojas et al. 2000, SAGARPA 2008, Ponce-Díaz et al. in press). Approximately 80% of all scallop production from Mexico is processed (the adductor muscle is separated) and approximately 82% of this processed muscle meat is exported to the United States (Félix-Pico 2006). When sold in the United States, Mexican Sea scallops are sold as frozen adductor muscle meat (Ponce-Díaz et al. in press). 20

Figure 9. Top left: capture trends of scallops and other bivalves (almejas) in different states of Mexico. BCS = Baja California Sur, BC = Baja California, SIN = Sinaloa, SON = Sonora. Top right: average production of scallops by state. Bottom left: average capture by species for Baja California Sur, by live weight. Mano de Leon represents the Mexican Sea scallop. Bottom right: average capture by species for Baja California Sur, by muscle weight (figure from SAGARPA 2004). 21

Scope of the analysis and the ensuing recommendation: This report covers diver-caught Mexican Sea scallops, also known as Lion s Paw scallops (Nodipecten subnodosus) in Laguna Ojo de Liebre and Guerrero Negro, Baja California Sur, Mexico. Seafood Watch has ranked this fishery as a Best Choice. Availability of Science Primary literature on the basic biology and best aquaculture methods for this species are available. Several book sections also offer biological information on the Mexican Sea scallop. Studies on population-level processes, such as intrinsic growth rates, do not exist. Abundance and size distribution data from fishery-independent annual stock assessments are available (Masso-Rojas et al. 2000, Ponce-Díaz et al. in press). Annual landings jointly covering the time period 1991 2007 are available from INAPESCA (National Fisheries Institute) internal documents and several other sources (Morales-Hernandez and Caceres-Martinez 1996, Masso-Rojas et al. 2000, Ponce-Díaz et al. 2009, Ponce-Díaz et al. in press). State and national annual landings of several combined bivalves are available from SAGARPA in their annual report, Anuario Estadístico de Acuacultura y Pesca (SAGARPA 2008). This report also contains data on human consumption of bivalves in Mexico and the proportion of the national capture fishery consisting of bivalves. Landings data consisting only of Mexican Sea scallops must be obtained from the INAPESCA regional office in La Paz, Baja California Sur. The most recent landings data (2007 2010) were unobtainable despite repeated efforts. None of these data sources on landings include landings standardized according to effort. Many details regarding the management of the Mexican Sea scallop fishery were obtained from internal documents of INAPESCA (Masso-Rojas et al. 2000), including currently open fishing grounds, methods for assessing stocks and setting quotas, and the process for granting permits. The enforcement status of this fishery remains unknown. Market Availability Common and market names: The Mexican Sea scallop is also known as the Lion s Paw scallop. It is often marketed simply as sea scallop, diver sea scallop, or diver-caught sea scallop, and may or may not be labeled as a product of Mexico. Seasonal availability: In the United States, the Mexican Sea scallop is sold as frozen adductor muscle meat (Ponce-Díaz et al. in press), and is generally available year-round. 22

Product forms: The Mexican Sea scallop is sold in the form of the frozen adductor muscle. The annual report from SAGARPA includes data on the amount of scallops ( almejas ) frozen versus canned (SAGARPA 2008). Import and export sources and statistics: Most scallops are exported as frozen adductor muscle meat, mainly to the United States (Félix-Pico 2006, Ponce-Díaz et al. in press). Import and export sources that provide information specifically on Mexican Sea scallops are not available except for time periods of a few years (e.g., 1991 1995), available from government documents (Morales-Hernandez and Caceres-Martinez 1996). III. Analysis of Seafood Watch Sustainability Criteria for Wild-caught Species Criterion 1: Inherent Vulnerability to Fishing Pressure Guiding Principle: Sustainable wild-caught species have a low vulnerability to fishing pressure, and hence a low probability of being overfished, because of their inherent life history characteristics. Primary factors 3 to evaluate Intrinsic rate of increase ( r ) High (> 0.16) Medium (0.05-0.16) Low (< 0.05) Unavailable/Unknown 3 These primary factors and evaluation guidelines follow the recommendations of Musick et al. (2000). Marine, estuarine, and diadromous fish stocks at risk of extinction in North America (exclusive of Pacific salmonids). Fisheries 25:6-30. 23

There are no population-level studies assessing the intrinsic rate of increase for Mexican Sea scallops. Age at 1 st maturity Low (< 5 years) Medium (5 10 years) High (> 10 years) Unavailable/Unknown Gonads appear at six months of age, first maturity occurs at eight months of age (65 80 mm shell length), and spawning commences within the first year (Barrios-Ruiz et al. 2003, Arellano-Martinez et al. 2004, Villalejo-Fuerte et al. 2004, Ponce-Díaz et al. in press). The minimum size limit is 140 mm shell length (Masso-Rojas et al. 2000). Masso-Rojas et al. 2000, Barrios-Ruiz et al. 2003, Arellano-Martinez et al. 2004, Villalejo-Fuerte et al. 2004, Ponce-Díaz et al. in press 24

Von Bertalanffy growth coefficient ( k ) High (> 0.16) Medium (0.05 0.15) Low (< 0.05) Unavailable/Unknown Depending on the time of year, the von Bertalanffy growth coefficient can range from 0.19 0.61 (Villalejo-Fuerte et al. 2004, Taylor et al. 2006). Villalejo-Fuerte et al. 2004, Taylor et al. 2006 Maximum age Low (< 11 years) Medium (11 30 years) High (> 30 years) Unavailable/Unknown 25

The maximum age of Mexican Sea scallops is unknown. Reproductive potential (fecundity) High (> 100 inds./year) Moderate (10 100 inds./year) Low (< 10 inds./year) Unavailable/Unknown The Mexican Sea scallop is a functional hermaphrodite, reproducing by releasing both eggs and sperm into the water where fertilization occurs. An individual scallop can release between 17 and 25 million eggs, and spawns at least once a year (Maldonado- Amparo et al. 2004). Fertilized eggs have a 45-day survival rate of ~4.5% (Petersen et al. 2008). Maldonado-Amparo et al. 2004, Petersen et al. 2008 26

Secondary factors to evaluate Species range Broad (e.g., species exists in multiple ocean basins, has multiple intermixing stocks or is highly migratory) Limited (e.g., species exists in one ocean basin) Narrow (e.g., endemism or numerous evolutionary significant units or restricted to one coastline) The Lion s Paw scallop can be found in the North Pacific and South Pacific oceans, ranging from the Baja California Peninsula in Mexico down to Peru (Barrios-Ruiz et al. 2003, Koch et al. 2005, Félix-Pico 2006). Barrios-Ruiz et al. 2003, Koch et al. 2005, Félix-Pico 2006 Special Behaviors or Requirements: Existence of special behaviors that increase ease or population consequences of capture (e.g., migratory bottlenecks, spawning aggregations, site fidelity, unusual attraction to gear, sequential hermaphrodites, segregation by sex, etc., OR specific and limited habitat requirements within the species range). No known behaviors or requirements OR behaviors that decrease vulnerability (e.g., widely dispersed during spawning) Some (i.e., 1 2) behaviors or requirements Many (i.e., > 2) behaviors or requirements 27

Mexican sea scallops have been known to move around over small scales (Masso-Rojas et al. 2000) but generally remain in the same area and exhibit high site fidelity. Masso-Rojas et al. 2000 Quality of Habitat: Degradation from non-fishery impacts Habitat is robust Habitat has been moderately altered by non-fishery impacts Habitat has been substantially compromised from non-fishery impacts and thus has reduced capacity to support this species (e.g., from dams, pollution, or coastal development) Some domestic wastewater and cannery sewage flows into the bays of the Baja California Peninsula along with pesticides from small agricultural areas (Félix-Pico 2006, Ponce-Díaz et al. in press). This relatively low quantity of discharge contains increased bacteria levels that may cause infections in scallop larvae and result in mass mortality (Ponce-Díaz et al. in press). A salt factory discharges hypersaline water into Laguna Ojo de Liebre. Félix-Pico 2006, Ponce-Díaz et al. in press 28

Synthesis Although the intrinsic rate of increase is unknown, other life history characteristics of the Mexican Sea scallop have been well studied. These scallops have fast growth rates, a short time to maturity, high reproductive output, and a broad species. Mexican sea scallops exhibit strong site fidelity, and the habitat of this species in Laguna Ojo de Liebre and Guerrero Negro has been moderately altered by domestic, industrial, and agricultural runoff. Overall, the biology of this species results in Seafood Watch deeming it to be inherently resilient to fishing pressure. Evaluation Guidelines 1) Primary Factors a) If r is known, use it as the basis for the rank of the Primary Factors. b) If r is unknown, then the rank from the remaining Primary Factors (in order of importance, as listed) is the basis for the rank. 2) Primary factors a) If a majority (2 out of 3) of the Primary factors rank as Red, reclassify the species into the next lower rank (i.e., Green becomes Yellow, Yellow becomes Red). No other combination of Primary factors can modify the rank from the Primary Factors. b) No combination of primary and secondary factors can result in a Critical Conservation Concern for this criterion. Conservation Concern: Inherent Vulnerability Low (Inherently Resilient) Moderate (Moderately Vulnerable) High (Highly Vulnerable) 29

Criterion 2: Status of Wild Stocks Guiding Principle: Sustainable wild-caught species have stock structure and abundance sufficient to maintain or enhance long-term fishery productivity. Primary factors to evaluate Management classification status Underutilized OR close to virgin biomass Fully fished OR recovering from overfished OR unknown Recruitment or growth overfished, overexploited, depleted or threatened The Mexican Sea scallop fishery of Laguna Ojo de Liebre and Guerrero Negro is considered by the National Fisheries Institute to be at optimum exploitation with no danger of overexploitation (Morales-Hernandez and Caceres-Martinez 1996, Masso-Rojas et al. 2000, Ponce-Díaz et al. 2009). Morales-Hernandez and Caceres-Martinez 1996, Masso-Rojas et al. 2000, Ponce-Díaz et al. 2009 Current population abundance relative to B MSY At or above B MSY (> 100%) Moderately Below B MSY (50 100%) OR unknown Substantially below B MSY (< 50%) 30

The value of B MSY is unknown because there is no information to estimate the total capacity of the complete lagunar region of Ojo de Liebre (Masso-Rojas et al. 2000); therefore, current biomass relative to B MSY is unknown. However, in 2000 the National Fisheries Institute believed that due to the fishery s overall increase in production since 1991, the maximum production level had yet to be reached. Harvest levels of 20 30% of biomass from legal-sized scallops are permitted each year after total biomass is determined from annual stock assessments of the indivdual fishing grounds. Masso-Rojas et al. 2000 Occurrence of overfishing (current level of fishing mortality relative to overfishing threshold) Overfishing not occurring (F curr /F msy < 1.0) Overfishing is likely/probable OR fishing effort is increasing with poor understanding of stock status OR Unknown Overfishing occurring (F curr /F msy > 1.0) Fishing mortality (F curr ) is at least 20 30% of the biomass of legal-sized clams (Masso-Rojas et al. 2000, Ponce-Díaz et al. in press), and is likely higher due to underreporting by licensed fishermen (Ponce-Díaz et al. in press). Because F MSY is unknown, F curr /F msy is also unknown. Masso-Rojas et al. 2000, Ponce-Díaz et al. in press 31

Overall degree of uncertainty in status of stock Low (i.e., current stock assessment and other fishery-independent data are robust OR reliable long-term fishery-dependent data available) Medium (i.e., only limited, fishery-dependent data on stock status are available) High (i.e., little or no current fishery-dependent or independent information on stock status OR models/estimates broadly disputed or otherwise out-of-date) Fishery-independent stock assessments are conducted annually by the Regional Fishery Center of La Paz (CRIP), which is part of the National Fisheries Institute (Morales-Hernandez and Caceres-Martinez 1996, Masso-Rojas et al. 2000, Félix-Pico 2006, Ponce-Díaz et al. in press). Data from these stock assessments covering 1996 2004 are available (Ponce-Díaz et al. in press); more recent stock assessments have been conducted, but the results are unavailable. Fishery-dependent landings data for Mexican Sea scallops are available for the time period 1991 2007 (Morales-Hernandez and Caceres-Martinez 1996, Masso-Rojas et al. 2000, Ponce-Díaz et al. 2009, Ponce-Díaz et al. in press). Although stock assessments are regularly conducted using fishery-independent data, biomass and fishing mortality reference points are not estimated. Morales-Hernandez and Caceres-Martinez 1996, Masso-Rojas et al. 2000, Ponce-Díaz et al. 2009, Ponce-Díaz et al. in press 32

Long-term trend (relative to species generation time) in population abundance as measured by either fishery-independent (stock assessment) or fishery-dependent (standardized CPUE) measures Trend is up Trend is flat or variable (among areas, over time or among methods) OR unknown Trend is down Data from fishery-independent stock assessments conducted annually by the Regional Fishery Center of La Paz (CRIP), which is part of the National Fisheries Institute, indicate that from 1996 2004, the long-term trend in abundance was variable (Fig. 2) (Ponce-Díaz et al. in press). Data from stock assessments after 2004 were unobtainable. Landings data from 1991 2007 indicate an overall increasing trend (Fig. 6) (Ponce-Díaz et al. 2009). Ponce-Díaz et al. 2009, Ponce-Díaz et al. in press Data on biomass landings are not standardized according to effort; CPUE data are not available for this fishery. Short-term trend in population abundance as measured by either fishery-independent (stock assessment) or fishery-dependent (standardized CPUE) measures Trend is up Trend is flat or variable (among areas, over time or among methods) OR unknown Trend is down 33

Data from fishery-independent stock assessments for the most recent five-year period available (2000 2004) indicate a short-term trend of flat and slightly variable abundance (Fig. 2) (Ponce-Díaz et al. in press). Data from stock assessments after 2004 were unobtainable. Landings data from the most recent five-year period available (2003 2007) indicate an overall increasing trend (Fig. 6) (Ponce-Díaz et al. 2009). Ponce-Díaz et al. 2009, Ponce-Díaz et al. in press Data on biomass landings are not standardized according to effort; CPUE data are not available for this fishery. Current age, size or sex distribution of the stock relative to natural condition Distribution(s) is(are) functionally normal Distribution(s) unknown Distribution(s) is(are) skewed Biomass distribution by size is estimated annually during stock assessments by the Regional Fishery Center of La Paz (CRIP). The most recent data, obtained for 1996 2000, show approximately normal (bell-shaped, not skewed) distributions of biomass by size, with a peak in the biomass abundance of legal-sized clams, 140mm in length (Fig. 3) (Masso-Rojas et al. 2000). Masso-Rojas et al. 2000 34

Synthesis The National Fisheries Institute considers the Mexican Sea scallop fishery to be at optimum exploitation with no danger of overexploitation. The value of B MSY is unknown, but the National Fisheries Institute stated in 2000 that maximum production level had not yet been reached as a result of overall increasing production since the fishery began in 1991. And while F MSY is also unknown, F curr is 20 30% of total biomass of legal-sized clams. There is a moderate degree of uncertainty in the status of the stock because, even though annual fishery-independent stock assessments are conducted and landings data are available, data from the most recent years are unobtainable. Data on biomass landings have not been standardized according to effort, and catch-per-unit-effort (CPUE) data are not available for this fishery. Long-term population abundance is variable while the short-term trend is arguably flat and slightly variable. The current biomass distribution of the stock is approximately normal (bell-shaped) and not skewed, with legal-sized clams still relatively abundant as of 2000. The stock status of Mexican Sea scallops is deemed by Seafood Watch to be a moderate conservation concern because the fishery is considered at optimum exploitation, B MSY and F MSY are unknown, and overall trends in population abundance are flat and/or variable. Evaluation Guidelines A Healthy Stock: 1) Is underutilized (near virgin biomass) 2) Has a biomass at or above B MSY AND overfishing is not occurring AND distribution parameters are functionally normal AND stock uncertainty is not high A Moderate Stock: 1) Has a biomass at 50 100% of B MSY AND overfishing is not occurring 2) Is recovering from overfishing AND short-term trend in abundance is up AND overfishing not occurring AND stock uncertainty is low 3) Has an Unknown status because the majority of primary factors are unknown. A Poor Stock: 1) Is fully fished AND trend in abundance is down AND distribution parameters are skewed 2) Is overfished, overexploited or depleted AND trends in abundance and CPUE are up. 3) Overfishing is occurring AND stock is not currently overfished. 35

A stock is considered a Critical Conservation Concern and the species is ranked Avoid, regardless of other criteria, if it is: 1) Overfished, overexploited or depleted AND trend in abundance is flat or down 2) Overfished AND overfishing is occurring 3) Listed as a threatened species or similar proxy by national or international bodies Conservation Concern: Status of Stocks Low (Stock Healthy) Moderate (Stock Moderate or Unknown) High (Stock Poor) Stock Critical Criterion 3: Nature and Extent of Bycatch Seafood Watch defines sustainable wild-caught seafood as marine life captured using fishing techniques that successfully minimize the catch of unwanted and/or unmarketable species (i.e., bycatch). Bycatch is defined as species that are caught but subsequently discarded (injured or dead) for any reason. Bycatch does not include incidental catch (non-targeted catch) if it is utilized, accounted for and managed in some way. Guiding Principle: A sustainable wild-caught species is captured using techniques that minimize the catch of unwanted and/or unmarketable species. 36

Primary factors to evaluate Quantity of bycatch, including any species of special concern (i.e., those identified as endangered, threatened or protected under state, federal or international law) Quantity of bycatch is low (< 10% of targeted landings on a per number basis) AND does not regularly include species of special concern Quantity of bycatch is moderate (10 100% of targeted landings on a per number basis) AND does not regularly include species of special concern OR Unknown Quantity of bycatch is high (> 100% of targeted landings on a per number basis) OR bycatch regularly includes threatened, endangered or protected species Mexican Sea scallops are harvested by divers operating from small boats equipped with outboard motors and compressors to supply air for one diver (also referred to as hookah diving ). Dredging has never been used (Morales-Hernandez and Caceres-Martinez 1996, Masso-Rojas et al. 2000, SAGARPA 2004, Koch et al. 2005, Félix-Pico 2006). As Mexican Sea scallops are individually hand extracted by divers, minimal bycatch occurs. Morales-Hernandez and Caceres-Martinez 1996, Masso-Rojas et al. 2000, SAGARPA 2004, Koch et al. 2005, Félix-Pico 2006 37

Population consequences of bycatch Low: Evidence indicates quantity of bycatch has little or no impact on population levels Moderate: Conflicting evidence of population consequences of bycatch OR unknown Severe: Evidence indicates quantity of bycatch is a contributing factor in driving one or more bycatch species toward extinction OR is a contributing factor in limiting the recovery of a species of special concern Mexican Sea scallops are harvested by divers operating from small boats equipped with outboard motors and compressors to supply air for one diver (also referred to as hookah diving ). Dredging has never been used (Morales-Hernandez and Caceres-Martinez 1996, Masso-Rojas et al. 2000, SAGARPA 2004, Koch et al. 2005, Félix-Pico 2006). As Mexican Sea scallops are individually hand extracted by divers, minimal bycatch occurs. The population consequences of bycatch are consequently assumed to be minimal. Morales-Hernandez and Caceres-Martinez 1996, Masso-Rojas et al. 2000, SAGARPA 2004, Koch et al. 2005, Félix-Pico 2006 Trend in bycatch interaction rates (adjusting for changes in abundance of bycatch species) as a result of management measures (including fishing seasons, protected areas and gear innovations): Trend in bycatch interaction rates is down Trend in bycatch interaction rates is flat OR unknown Trend in bycatch interaction rates is up Not applicable because quantity of bycatch is low 38

Mexican Sea scallops are harvested by divers operating from small boats equipped with outboard motors and compressors to supply air for one diver (also referred to as hookah diving ); Dredging has never been used (Morales-Hernandez and Caceres-Martinez 1996, Masso-Rojas et al. 2000, SAGARPA 2004, Koch et al. 2005, Félix-Pico 2006). As Mexican Sea scallops are individually hand extracted by divers, minimal bycatch occurs. Morales-Hernandez and Caceres-Martinez 1996, Masso-Rojas et al. 2000, SAGARPA 2004, Koch et al. 2005, Félix-Pico 2006 Secondary factor to evaluate Evidence that the ecosystem has been or likely will be substantially altered (relative to natural variability) in response to the continued discard of the bycatch species Studies show no evidence of ecosystem impacts Conflicting evidence of ecosystem impacts OR unknown Studies show evidence of substantial ecosystem impacts No studies have assessed the ecosystem impacts of discarding bycatch associated with the Mexican Sea scallop fishery. Minimal bycatch is associated with this fishery due to the extraction method, and there are likely no ecosystem impacts. The food web impacts of removing Mexican Sea scallops are unknown. 39