California Halibut Paralichthys californicus Monterey Bay Aquarium U.S. Pacific Bottom gillnet, Bottom trawl, Hook and line November 4, 2013 Kelsey James, Consulting Researcher Disclaimer Seafood Watch strives to ensure all our Seafood Reports and the recommendations contained therein are accurate and reflect the most up-to-date evidence available at time of publication. All our reports are peerreviewed for accuracy and completeness by external scientists with expertise in ecology, fisheries science or 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. We always welcome additional or updated data that can be used for the next revision. Seafood Watch and Seafood Reports are made possible through a grant from the David and Lucile Packard Foundation.
2 Final Seafood Recommendation Stock / Fishery California halibut: Southern California California: Southern Northeast Pacific - Trawl, Bottom California halibut: Southern California California: Southern Northeast Pacific - Hook/line California halibut: Southern California California: Southern Northeast Pacific - Gillnet, Bottom California halibut: Central California California: Central Northeast Pacific - Hook/line Impacts on the Stock Yellow (2.64) Yellow (2.64) Yellow (2.64) Impacts on other Spp. Red (2.05) Management Habitat and Overall Ecosystem Recommendation Yellow (3.00) Yellow (3.00) Good Alternative (2.643) Green (4.75) Yellow (3.00) Green (3.46) Best Choice (3.380) Red (1.82) California halibut: Central Green (4.28) Red (1.94) California California: Central Northeast Pacific - Trawl, Bottom Yellow (3.00) Green (3.46) Good Alternative (2.659) Green (4.28) Green (4.75) Yellow (3.00) Green (3.46) Best Choice (3.813) Yellow (3.00) Yellow (3.00) Good Alternative (2.942) Scoring note scores range from zero to five where zero indicates very poor performance and five indicates the fishing operations have no significant impact. Final Score = geometric mean of the four Scores (Criterion 1, Criterion 2, Criterion 3, Criterion 4). Best Choice = Final Score between 3.2 and 5, and no Red Criteria, and no Critical scores Good Alternative = Final score between 2.2 and 3.199, and Management is not Red, and no more than one Red Criterion other than Management, and no Critical scores Avoid = Final Score between 0 and 2.199, or Management is Red, or two or more Red Criteria, or one or more Critical scores.
3 Executive Summary California halibut (Paralichthys californicus) are found off the Quillayute River, Washington to southern Baja California, but are most common from Bodega Bay, California and south. This report addresses the bottom gillnet, hook and line, and bottom trawl fisheries for this species throughout its range. California halibut has a moderate inherent vulnerability based on a productivity and susceptibility analysis (PSA). The first ever stock assessment was published in 2011 indentifying two stocks: a southern and a central stock. Bottom trawl and hook and line fish both stocks, while bottom gillnet only fishes the southern stock. The southern stock was estimated as depleted to 14% of the unexploited biomass, but the biomass has remained constant since the 1970s therefore it is of moderate concern since there are no reference points to compare with. The central stock was estimated at 122% of the unexploited biomass and is of very low concern. The fishing mortality for both stocks was estimated below the level that would prodice maximum sustainable yield (MSY), although the appropriateness of MSY as a reference point is in question. Due to the unknown fishing mortality in relation to an appropriate reference point the fishing mortality is of moderate concern for both stocks. The humpback whale has the lowest scores overall, but is only subject to entanglement in the gillnet fishery. It has a high inherent vulnerability and a high stock status concern because it is listed as endangered on the endangered species list. The humpback whale has low fishing mortality based on the combination of very low known entanglements in the California halibut bottom gillnet fishery and the low annual mortality throughout California relative to the allowed Potential Biological Removal (PBR). Sea otters, while listed as threatened on the endangered species list, were not included as bycatch in the California halibut gillnet fishery because the recent gillnet depth restrictions eliminated overlap of sea otters and the gillnet fishery resulting in sea otter entanglement that is at or near zero. The lowest scoring species in the California bottom trawl fishery is the bat ray mainly due to its high inherent vulnerability and the lack of a stock assessment and reference points. The bat ray is susceptible to the fishery, but has unknown fishing mortality resulting in a moderate score. The bottom trawl fishery also experiences a wide variety of bycatch (36 groundfish species, 23 shark, skate, and ray species, and 60 other finfish and invertebrates in 2011) that occur in low numbers, are not of conservation concern, and therefore not assessed as bycatch species in this report. An exception is a large amount of unidentified jellyfish bycatch, but it also is not believed to be of conservation concern and is not included. The hook and line fishery is very species selective and while bycatch does occur no species occur in large enough numbers to be included here. Additionally, hook and line fishermen make significant efforts to release unwanted bycatch
4 alive including releasing them without removing them from the water. Management restrictions on gear use for the California halibut fisheries started in 1911. A stock assessment for California halibut was first published in 2011, and another is planned within the decade, with several monitoring programs underway which are used to assess the California halibut stocks. Management of all fisheries is considered moderately effective, as the fishery lacks reference points, quotas or a strategy to recover the southern stock from depleted levels, but has regulations in place that allow for at least one year of female spawning before they become susceptible to the fishery, and incorporates effective monitoring, enforcement, scientific advice and stakeholder input. Overall management of retained and discarded species is moderate the all California halibut fisheries. The trawl fishery catches a wide diversity of species but has many regulations in place to help constrain bycatch of species of concern. Bycatch stocks that are threatened or endangered have up-to-date assessments, but several other bycatch species do not have assessments, including the white shark, which was recently considered for, but denied a threatened or endangered status in California. Bottom trawls score the lowest since they have the stongest impact on the substrate, but are only of moderate concern as they operate predominately over soft sediment and have strong mitigation in place. However there is no evidence that an assessment of ecosystem impacts is underway. The hook and line fishery has the lowest impact on the substrate, but does not have any mitigation in place or any ecosystem based assessments in preparation. The gillnet fishery scores with the hook and line fishery based on substrate contact on soft sediments, the strong mitigation through depth restrictions and minimal mesh sizes, and that there are no ecosystem based assessments in preparation for this fishery.
5 Table of Contents Final Seafood Recommendation... 2 Executive Summary... 3 Introduction... 6 Analysis... 10 Criterion 1: Stock for which you want a recommendation... 10 Criterion 2: Impacts on other retained and bycatch stocks... 19 Criterion 3: Management effectiveness... 34 Criterion 4: Impacts on the habitat and ecosystem... 50 Acknowledgements... 55 References... 56 About Seafood Watch... 63 Guiding Principles... 64
6 Introduction Scope of the analysis and ensuing recommendation California halibut (Paralichthys californicus) are found off the Quillayute River, Washington to southern Baja California, but are most common from Bodega Bay, California and south. This report addresses the bottom gillnet, hook and line, and bottom trawl fisheries for this species in California. Overview of the species and management bodies California halibut (Paralichthys californicus) inhabit waters of the eastern North Pacific from the Quillayute River, Washington to southern Baja California, but are most common from Bodega Bay, California and south {Love 1996}. They attain 1.5 m in length, 32 kg in weight and are found most commonly on soft bottoms near vertical strucuture (e.g. rocky reef) {Love 1996}. Males become sexual mature at 3 years and females at 4 {Love and Brooks 1990} {Pattison and McAllister 1990} {Kucas and Hassler 1986} and live up to 30 years {Love 1996}. California halibut are oviparous with broadcast spawning and females may produce up to one million eggs per spawning event, but sucessful recruitment is dependent on favorable environmental conditions and the availability of suitable nursery habitat {CalCOFI 2012}. Three gear types fish commercially for California halibut: bottom trawl, hook and line, and bottom gillnet. Both bottom trawl and hook and line are operated throughout California (mainly south of Bodega Bay), while bottom gillnet operates south of Point Conception {CalCOFI 2012}. Recreational fishing, which will not be addressed in this report, is conducted with hook and line only. The California Department of Fish and Wildlife (CDFW) manages the California halibut fisheries, except the limited entry (LE) California halibut bottom trawl fishery, which is subject to the federally managed Shorebased Individual Fishing Quota (IFQ) Fishery. The management of the California halibut fisheries has been evolving since the early 1900s {CDFG 2011a}. Today neither bottom trawling (except in the California Halibut Trawl Grounds (CHTG)) nor gillnets are legal in state waters (0-3 nm from shore) and both require limited entry permits (except fishing in the CHTG (Figure 1), which requires a state permit) {CalCOFI 2012} {CDFG 2008} {CDFG 2011a}. Trawl gear has been the dominate gear used recently due to increased gillnet restrictions and accounted for 49% of the total catch in 2011, while hook and line accounted for 29% and gillnet accounted for 21% {CalCOFI 2012}.
7 Figure 1. Map of the area within state waters where trawling is legal, aka California halibut trawl grounds (CHTG). Adapted from CDFG 2008. Production Statistics Total California halibut landings were 199.7 t in 2011, with 98.8 t from bottom trawls, 58.7 t from hook and line, and 41.6 t from gillnets {CalCOFI 2012}. It is estimated that 117 t of California halibut were caught recreationally (mainly hook and line) in 2011 {CalCOFI 2012}. The coast of California and Baja California are the only locations of California halibut production worldwide. In 2005, artisanal fishers around La Paz Bay, Mexico caught approximately 16 t of California halibut, but production from Mexico is otherwise unknown. Overall production has decreased over time (Figure 2) and changed from gillnet dominated to bottom trawl dominated (Figure 3). Commercial catch peaked in the 1910s, and 1940s especially south of Point Conception (Figure 2).
8 Figure 2. Commercial catch (metric tons) from 1915 to 2010 north and south of Point Conception. Adapted from CDFG 2011a. Figure 3. Commercial catch of California halibut by gear type from 1981-2011. Adapted from CalCOFI 2012. Importance to the US/North American market California halibut is mainly fished domestically. Potentially 26.5 mt of California halibut were imported from Mexico in 2012, but it is simply listed as 'not specified halibut' {NMFS 2012c}.
9 Common and market names The common name is California halibut. The market name is Halibut and other vernacular names include bastard halibut and Monterey halibut {Love 1996} {FDA 2012}. Primary product forms Primarily sold fresh as fillets and steaks, but some are frozen {Love 1996}. Additionally a recent fishery has developed for live halibut {Love 1996}.
10 Analysis Scoring Guide All scores result in a zero to five final score for the criterion and the overall final rank. A zero score indicates poor performance, while a score of five indicates high performance. The full Seafood Watch Fisheries Criteria that the following scores relate to are available on our website at http://www.seafoodwatch.org Criterion 1: Stock for which you want a recommendation This criterion evaluates the impact of fishing mortality on the species, given its current abundance. The inherent vulnerability to fishing rating influences how abundance is scored, when abundance is unknown. The final Criterion 1 Score is determined by taking the geometric mean of the abundance and fishing mortality scores. Summary CALIFORNIA HALIBUT: CENTRAL CALIFORNIA Region / Method Inherent Vulnerability Stock Status Fishing Mortality California: Central Northeast Pacific 2.00:Medium 5.00:Very Low 3.67:Low Hook/line California: Central Northeast Pacific 2.00:Medium 5.00:Very Low 3.67:Low Trawl, Bottom Subscore Green (4.284) Green (4.284) CALIFORNIA HALIBUT: SOUTHERN CALIFORNIA Region / Method Inherent Vulnerability California: Southern Northeast Pacific Gillnet, Bottom California: Southern Northeast Pacific Hook/line California: Southern Northeast Pacific Trawl, Bottom Stock Status 2.00:Medium 3.00:Moderate 2.00:Medium 3.00:Moderate 2.00:Medium 3.00:Moderate Fishing Subscore Mortality 2.33:Moderate Yellow (2.644) 2.33:Moderate Yellow (2.644) 2.33:Moderate Yellow (2.644)
11 Justification of Ranking CALIFORNIA HALIBUT: CENTRAL CALIFORNIA Factor 1.1 - Inherent Vulnerability to Fishing Low = FishBase vulnerability score for species 0-35 OR species exhibits life history characteristics that make it resilient to fishing, e.g., early maturing (<5 years), short lived (< 10 years), small maximum size, and low on food chain. Medium = FishBase vulnerability score for species 36-55 OR life history characteristics that make it neither particularly vulnerable or resilient to fishing, e.g. moderate age at sexual maturity (5-15 years), moderate maximum age (10-25 years), moderate maximum size, and middle of food chain. High = FishBase vulnerability score for species 56-100 OR life history characteristics that make is particularly vulnerable to fishing, e.g. long-lived (>25 years), late maturing (>15 years), low reproduction rate, large body size, and top-predator. Note: The FishBase vulnerability scores is an index of the inherent vulnerability of marine fishes to fishing based on life history parameters: maximum length, age at first maturity, longevity, growth rate, natural mortality rate, fecundity, spatial behaviors (e.g. schooling, aggregating for breeding, or consistently returning to the same sites for feeding or reproduction) and geographic range. California: Central Northeast Pacific, Hook/line 2.00 Medium The vulnerability of California halibut, Paralichthys californicus, is calculated by a productivity and susceptibility analysis (PSA) by averaging the scores of six productivity attributes. The average age at maturity is estimated at 4 years for females and between one and three years for males {Love and Brooks 1990}. The maximum reported age is 30 years old {Pattison and McAllister 1990}, however other studies have only found maximum ages of 19 {CDFG 2011a} and 13 {MacNair et al. 2001} for females and maximum male ages are 23 and 16 {Pattison and McAllister 1990} and 16 {CDFG 2011a}. Several additional studies have shown that individuals over 10 years are uncommon {Sunada et al. 1990} {Pattison and McAllister 1990} {MacNair et al. 2001}, therefore the average maximum age is likely less than 25 years old. The maximum size of California halibut is 150 cm {Love 1996} and the average size at maturity is 47 cm for females and 23 cm for males {Love and Brooks 1990}. The reproductive strategy is broadcast spawning with as many as 1 million eggs released in one spawning event {CalCOFI 2012}. Adult California halibut feed primarily on fishes including: northern anchovy (Engraulis mordax), topsmelt (Atherinops affinis), California killifish (Fundulus parvipinnis), various gobies, white croaker (Genyonemus lineatus), hornyhead turbot (Pleuronichthys verticalis), Pacific saury (Cololabis saira), Pacific herring (Clupea pallasii), sanddabs, and white seaperch (Phanerodon furcatus) with the
12 occasional crustacean or squid {Bain and Bain 1971}{Allen 1990}{Plummer et al. 1983}{Haaker 1975}. The tropic level is estimated at 4.5 {Froese and Pauly 2013}. These six attributes average 2.0 which correspond to a moderate inherent vulnerability. Factor 1.2 - Abundance 5 (Very Low ) = Strong evidence that population is above target abundance level (e.g. biomass at maximum sustainable yield, BMSY) or near virgin biomass 4 (Low ) = Population may be below target abundance level, but it is considered not overfished. 3 (Moderate ) = Abundance level is unknown and species has a low or medium inherent vulnerability to fishing 2 (High ) = Population is overfished, depleted, or a species of concern OR Abundance is unknown and species has a high inherent vulnerability to fishing. 1 (Very High ) = Population is listed as threatened or endangered. Figure 4: Central stock spawning biomass depletion over time. Adapted from CDFW 2011. California: Central Northeast Pacific, Hook/line 5.00 Very Low The first ever stock assessment for California halibut was completed in 2011. California halibut was
13 assessed in two stocks: a southern stock, south of Point Conception, and a central stock, north of Point Conception {CDFG 2011a}, however there is no evidence of genetically different stocks throughout the geographic range of California halibut {Craig et al. 2011}. The spawning biomass of the central stock was estimated to have increased substantially since 1980 due to high recruitment and was estimated at 122% of the unexploited spawning biomass level (Figure 4) {CDFG 2011}. The conservation concern for the central stock is very low. Rationale: The central stock population is estimated to have increased rapidly starting in 1995 due to large recruitments, which appear to occur in a cyclic pattern (Figure 4) {CDFG 2011}. There were some technical issues with the models so the parameter estimates may not be reliable, but the general conclusions remain consistent for the different estimated parameters {CDFG 2011}. Factor 1.3 - Fishing Mortality 5 (Very Low ) = Highly likely that fishing mortality is below a sustainable level (e.g., below fishing mortality at maximum sustainable yield, FMSY) OR fishery does not target species and its contribution to the mortality of species is negligible ( 5% of a sustainable level of fishing mortality) 3.67 (Low ) = Probable (>50% chance) that fishing mortality is at or below a sustainable level, but some uncertainty OR fishery does not target species and does not adversely affect species, but its contribution to mortality is not negligible OR fishing mortality is unknown, but the population is healthy and the species has a low susceptibility to the fishery (low chance of being caught) 2.33 (Moderate ) = Fishing mortality is fluctuating around sustainable levels OR fishing mortality is unknown and species has a moderate-high susceptibility to the fishery, and if species is depleted, reasonable management is in place. 1 (High ) = Overfishing is occurring, but management is in place to curtail overfishing OR fishing mortality is unknown, species is depleted and no management is in place
14 0 = (Critical) = Overfishing is known to be occurring and no reasonable management is in place to curtail overfishing. Figure 5. Catch by gear north of Point Conception. Adapted from CDFW2011. California: Central Northeast Pacific, Hook/line 3.67 Low The central stock has an estimated fishing mortality lower than the level that would produce MSY {CDFG 2011a}. The current fishing mortality would have to be multiplied by 36.76 to achieve MSY {CDFG 2011a}. However, no stock status reference points have been developed for California halibut {CDFG 2011a}. The estimated MSY based reference points are inappropriate based on the biology of the California halibut and the assumption that recruitment is independent of stock size causes the spawning biomass associated with MSY to occur at a high depletion level (7-12% of the unexploited spawning biomass) {CDFG 2011a}. The 25% proxy level might be a reasonable reference point {CDFG 2011a}. The stock assessment conclusion was that fishing is not a limiting constraint on the central California population {CDFG 2011a}; therefore the fishing morality for the central stock is low. Rationale: Catch by region over time is generally similar, but gear types are used in different proportions (Figure 5).
15 CALIFORNIA HALIBUT: SOUTHERN CALIFORNIA 1.1 - Inherent Vulnerability California: Southern Northeast Pacific, Gillnet, Bottom California: Southern Northeast Pacific, Hook/line California: Southern Northeast Pacific, Trawl, Bottom 2.00 Medium The vulnerability of California halibut, Paralichthys californicus, is calculated by a productivity and susceptibility analysis (PSA) by averaging the scores of six productivity attributes. The average age at maturity is estimated at 4 years for females and between one and three years for males {Love and Brooks 1990}. The maximum reported age is 30 years old {Pattison and McAllister 1990}, however other studies have only found maximum ages of 19 {CDFG 2011a} and 13 {MacNair et al. 2001} for females and maximum male ages are 23 and 16 {Pattison and McAllister 1990} and 16 {CDFG 2011a}. Several additional studies have shown that individuals over 10 years are uncommon {Sunada et al. 1990} {Pattison and McAllister 1990} {MacNair et al. 2001}, therefore the average maximum age is likely less than 25 years old. The maximum size of California halibut is 150 cm {Love 1996} and the average size at maturity is 47 cm for females and 23 cm for males {Love and Brooks 1990}. The reproductive strategy is broadcast spawning with as many as 1 million eggs released in one spawning event {CalCOFI 2012}. Adult California halibut feed primarily on fishes including: northern anchovy (Engraulis mordax), topsmelt (Atherinops affinis), California killifish (Fundulus parvipinnis), various gobies, white croaker (Genyonemus lineatus), hornyhead turbot (Pleuronichthys verticalis), Pacific saury (Cololabis saira), Pacific herring (Clupea pallasii), sanddabs, and white seaperch (Phanerodon furcatus) with the occasional crustacean or squid {Bain and Bain 1971}{Allen 1990}{Plummer et al. 1983}{Haaker 1975}. The tropic level is estimated at 4.5 {Froese and Pauly 2013}. These six attributes average 2.0 which correspond to a moderate inherent vulnerability.
16 1.2 - Stock Status Figure 6. Southern stock spawning biomass depletion over time. Adapted from CDFW 2011. California: Southern Northeast Pacific, Gillnet, Bottom California: Southern Northeast Pacific, Hook/line California: Southern Northeast Pacific, Trawl, Bottom 3.00 Moderate The first ever stock assessment for California halibut was completed in 2011. California halibut was assessed in two stocks: a southern stock, south of Point Conception, and a central stock, north of Point Conception {CDFG 2011a}. The spawning biomass of the southern stock was estimated to be depleted to 14% of the unexploited spawning biomass level, however the spawning biomass was estimated to be low since the start of the modeling period (1971) and to be above the level that would produce MSY (Figure 6) {CDFG 2011a}. It should be noted that MSY is not an appropriate reference point based on the biology of the California halibut, especially that it occurs at such a high depletion level. The overfished limit reference point for other Northeast Pacific flatfish is 12.5% of the unexploited spawning biomass, while 25% of the unexploited biomass is the biomass at MSY proxy {Haltuch et al. 2011}{Hicks and Wetzel 2011}{Kaplan and Helser 2007}. Since no reference point has been determined the conservation concern for the southern stock is a moderate concern. Rationale:
17 The southern stock spawning biomass has been estimated to be low since the start of the modeling time period (1971; Figure 6) {CDFG 2011a}. The California halibut are prolific enough and have a high reproductive potential that when environmental conditions are favorable, biomass can increase relatively quickly in a short time {CDFG 2011a}. The assumption is made that recruitment is independent of stock size, at least at the observed abundance levels, which is not contradicted by the data {CDFG 2011a}. Recruitments since 1999 are estimated to have been low, which is supported by the data {CDFG 2011a}. The MSY is estimated to occur at a very low fraction of the unexploited biomass (7-12% of the unexploited spawning biomass level) {CDFG 2011a}. 1.3 - Fishing Mortality Figure 7. Catch by gear type south of Point Conception. Adapted from CDFW 2011. California: Southern Northeast Pacific, Gillnet, Bottom California: Southern Northeast Pacific, Hook/line California: Southern Northeast Pacific, Trawl, Bottom 2.33 Moderate The southern stock has an estimated fishing mortality lower than the level that would produce MSY
18 {CDFG 2011a}. The current fishing mortality would have to be multiplied by 4.49 for the southern stock to achieve MSY {CDFG 2011a}. However, no stock status reference points have been developed for California halibut {CDFG 2011a}. The estimated MSY based reference points are inappropriate based on the biology of the California halibut and the assumption that recruitment is independent of stock size causes the spawning biomass associated with MSY to occur at a high depletion level (7-12% of the unexploited spawning biomass) {CDFG 2011a}. The 25% proxy level might be a reasonable reference point {CDFG 2011a}. The stock assessment states that although California halibut has sustained high fishing levels for decades, management action may be needed to reduce the risk of fishery collapse in southern California {CDFG 2011a}. The fishing mortality for the southern stock is moderate based on the unknown fishing mortality in relation to an appropriate reference point. Rationale: Catch by region over time is generally similar, but gear types are used in different proportions (Figure 7).
19 Criterion 2: Impacts on other retained and bycatch stocks All retained and primary bycatch species in the fishery are evaluated in the same way as the species under assessment were evaluated in Criterion 1. Seafood Watch defines bycatch as all fisheries-related mortality or injury other than the retained catch. Examples include discards, endangered or threatened species catch, and ghost fishing. To determine the final Criterion 2 score, the score for the lowest scoring retained/bycatch species is multiplied by the discard rate score (ranges from 0-1), which evaluates the amount of non-retained catch (discards) and bait use relative to the retained catch. Summary California halibut: Central California: California: Central Northeast Pacific, Hook/line Subscore:: 5.000 Discard Rate: 0.95 C2 Rate: 4.750 Species CALIFORNIA HALIBUT: CENTRAL CALIFORNIA Inherent Stock Status Vulnerability 2.00: Medium 5.00: Very Low Fishing Mortality 3.67: Low Subscore 4.284 California halibut: Central California: Subscore:: 2.159 Discard Rate: 0.90 C2 Rate: 1.943 Species Inherent Vulnerability Stock Status BAT RAY 1.00: High 2.00: High BIG SKATE: PACIFIC COAST OTHER 1.00: High 2.00: High GROUNDFISH COMPLEX LONGNOSE SKATE: PACIFIC COAST 2.00: Medium 4.00: Low DUNGENESS CRAB 3.00: Low 3.00: Moderate CALIFORNIA HALIBUT: CENTRAL 2.00: Medium 5.00: Very CALIFORNIA Low Fishing Mortality 2.33: Moderate 3.67: Low 3.67: Low 5.00: Very Low 3.67: Low Subscore 2.159 2.709 3.831 3.873 4.284
20 California halibut: Southern California: California: Southern Northeast Pacific, Gillnet, Bottom Subscore:: 1.916 Discard Rate: 0.95 C2 Rate: 1.820 Species Inherent Vulnerability Stock Status Fishing Mortality HUMPBACK WHALE: 1.00: High 1.00: Very 3.67: Low CALIFORNIA/OREGON/WASHINGTON High WHITE SHARK 1.00: High 2.00: High 2.33: Moderate CALIFORNIA HALIBUT: SOUTHERN CALIFORNIA 2.00: Medium 3.00: Moderate SKATES (UNSPECIFIED) 1.00: High 2.00: High 2.33: Moderate 3.67: Low Subscore 1.916 2.159 2.644 2.709 California halibut: Southern California: California: Southern Northeast Pacific, Hook/line Subscore:: 5.000 Discard Rate: 0.95 C2 Rate: 4.750 Species CALIFORNIA HALIBUT: SOUTHERN CALIFORNIA Inherent Stock Status Vulnerability 2.00: Medium 3.00: Moderate Fishing Mortality 2.33: Moderate Subscore 2.644 California halibut: Southern California: California: Southern Northeast Pacific, Trawl, Bottom Subscore:: 2.159 Discard Rate: 0.95 C2 Rate: 2.051 Species Inherent Vulnerability Stock Status BAT RAY 1.00: High 2.00: High CALIFORNIA HALIBUT: SOUTHERN CALIFORNIA 2.00: Medium 3.00: Moderate 1.00: High 2.00: High BIG SKATE: PACIFIC COAST OTHER GROUNDFISH COMPLEX LONGNOSE SKATE: PACIFIC COAST 2.00: Medium 4.00: Low Fishing Mortality 2.33: Moderate 2.33: Moderate 3.67: Low 3.67: Low Subscore 2.159 2.644 2.709 3.831 The humpback whale has the lowest scores overall, but is only subject to entanglement in the gillnet fishery. It has a high inherent vulnerability and a high stock status concern because it is listed as endangered on the endangered species list. The humpback whale has low fishing mortality based on the
21 combination of very low known entanglements in the California halibut bottom gillnet fishery and the low annual mortality throughout California relative to the allowed Potential Biological Removal (PBR). Sea otters, while listed as threatened on the endangered species list, were not included as bycatch in the California halibut gillnet fishery because the gillnet depth restrictions eliminated overlap of sea otters and the gillnet fishery resulting in sea otter entanglement that is at or near zero. The lowest scoring species in the California bottom trawl fishery is the bat ray mainly due to its high inherent vulnerability and the lack of a stock assessment and reference points. The bat ray is susceptible to the fishery, but has unknown fishing mortality resulting in a moderate score. The bottom trawl fishery also experiences a wide variety of bycatch (36 groundfish species, 23 shark, skate, and ray species, and 60 other finfish and invertebrates in 2011) that occur in low numbers, are not of conservation concern, and therefore not assessed as bycatch species in this report. An exception is a large amount of unidentified jellyfish bycatch, but it also is not believed to be of conservation concern and is not included. The hook and line fishery is very species selective and while bycatch does occur no species occur in large enough numbers to be included here. Additionally, hook and line fishermen make significant efforts to release unwanted bycatch alive including releasing them without removing them from the water. Justification of Ranking Only species that scored red are included here. All other species evaluations are in Appendix 1. See criterion 1 for scoring definitions. Bat Ray 2.1 - Inherent Vulnerability California: Southern Northeast Pacific, Trawl, Bottom 1.00 High Bat ray, Myliobatis californica, has a vulnerability score of 75 out of 100 {Froese and Pauly 2013}, therefore it has a high inherent vulnerability. 2.2 - Stock Status California: Southern Northeast Pacific, Trawl, Bottom
22 2.00 High The stock status of bat rays is unknown. There is no stock assessment available for this species. For this reason and the high inherent vulnerability, bat rays are of high conservation concern. 2.3 - Fishing Mortality California: Southern Northeast Pacific, Trawl, Bottom 2.33 Moderate The level of fishing mortality on bat rays from the California halibut bottom trawl fishery is unknown. Bat rays are a shallow dwelling species (0-108 m) and utilize estuaries in addition to sandy bottoms and kelp forests {Love et al. 2005}. The bottom trawl restrictions on state waters likely protect a large portion of the bat ray stock. Additionally, bat rays caught in this bottom trawl fishery are almost 100% discarded {NWFSC 2012} and subsequent discard survival is probable as evidenced by post-release survival studies of batoids in other regions {Braccini et al. 2012}{Enever et al. 2009}{Laptikhovsky 2004}. It is likely that the stock is not depleted, but bat rays are susceptible to this fishery, therefore the fishing mortality is of moderate concern. 2.4 - Discard Rate The discard rate is the sum of all dead discards (i.e. non-retained catch) plus bait use divided by the total retained catch. California: Southern Northeast Pacific, Trawl, Bottom 0.90 40-60% The California halibut discard to landings ratio were 81%, 74%, and 76% for 2009, 2010, and 2011 respectively {NWFSC 2012}. Fifty percent or more of the discards were dungeness crab {NWFSC 2012} which likely have high post-release survival rates. Dungeness crab mortality from trawls off Washington are estimated at 2% for hardshelled crabs and 9% for softshelled crabs {Alverson et al. 1994}. Therefore approximately 10% of the discarded dungeness crabs do not survive. The California discard to landings ratio excluding crab were 39%, 32%, and 36% for 2009, 2010, and 2011 respectively. Adding 10% mortality of dungeness crabs results in a discard to landings ratio between 40 and 60%.
23 Big Skate: Pacific Coast other Groundfish Complex 2.1 - Inherent Vulnerability California: Southern Northeast Pacific, Trawl, Bottom 1.00 High Big skate, Beringraja binoculata, has a vulnerability score of 86 out of 100 {Froese and Pauly 2013}, therefore it has a high inherent vulnerability. 2.2 - Stock Status California: Southern Northeast Pacific, Trawl, Bottom 2.00 High There is no stock assessment for the big skate, and therefore, no reference points or biomass estimates. Additionally this species is listed as a near threatened species by the IUCN {IUCN 2012}. The combination of the unknown stock status, a high inherent vulnerability, and a near threatened listing results in a high conservation concern. 2.3 - Fishing Mortality California: Southern Northeast Pacific, Trawl, Bottom 3.67 Low There is no stock assessment for the big skate, and therefore, no reference points are available. It was assessed by the Pacific Fisheries Management Council using a data poor method to assist in the calculation of an overfishing limit (OFL) {PFMC and NMFS 2012}. The estimated OFL is 518 mt, and in 2011 the total catch (including discards) in the California halibut trawl fishery was 9.56 mt {PFMC and NMFS 2012}{NWFSC 2012}. For scale, the total catch (including discards) in the groundfish bottom trawl was 53.92 mt {NWFSC 2012}. Using this OFL it is very probable that fishing mortality is at or below a sustainable level, but due to the lack of data for this species, the fishing mortality is deemed of low concern.
24 2.4 - Discard Rate The discard rate is the sum of all dead discards (i.e. non-retained catch) plus bait use divided by the total retained catch. 0.90 40-60% The California halibut discard to landings ratio were 81%, 74%, and 76% for 2009, 2010, and 2011 respectively {NWFSC 2012}. Fifty percent or more of the discards were Dungeness crab {NWFSC 2012} which likely have high post-release survival rates. Dungeness crab mortality from trawls off Washington are estimated at 2% for hardshelled crabs and 9% for softshelled crabs {Alverson et al. 1994}. Therefore approximately 10% of the discarded dungeness crabs do not survive. The California discard to landings ratio excluding crab were 39%, 32%, and 36% for 2009, 2010, and 2011 respectively. Adding 10% mortality of dungeness crabs results in a discard to landings ratio between 40 and 60%. California: Southern Northeast Pacific, Trawl, Bottom 0.95 20-40% The California halibut discard to landings ratio overall were 81%, 74%, and 76% for 2009, 2010, and 2011 respectively {NWFSC 2012}. Fifty percent or more of the discards were Dungeness crab {NWFSC 2012} which do not occur south of Point Conception. Therefore the discard to landings ratio excluding dungeness crabs were 39%, 32%, and 36% for 2009, 2010, and 2011 respectively {NWFSC 2012}. These values fall between a 20-40% discard to landings ratio. Dungeness crab 2.1 - Inherent Vulnerability 3.00 Low The vulnerability of Dungeness crabs, Metacarcinus magister, is calculated by a productivity and susceptibility analysis (PSA) by averaging the scores of four productivity attributes. The average age at maturity is two years, while the average maximum age is six to eight years {Leet et al. 2001}. Dungeness crabs brood the eggs before releasing the larvae for distribution {Leet et al. 2001}. One female can have between 100,000 and 1,600,000 eggs per year {Leet et al. 2001}. There is no evidence of depensatory or compensatory dynamics; population size is based on recruitment success, which is driven by atmospheric forcing {Shanks and Roegner 2007}. These life history characters result in score of 3, 3, 2,
25 and 2 in the Seafood Watch inherent vulnerability table for invertebrates (SFW criteria), which average to 2.5. Based on this dungeness crabs have a low inherent vulnerability. 2.2 - Stock Status 3.00 Moderate There is no stock assessment available for dungeness crabs. Population size depends on the recruitment success of larvae, which is driven by atmospheric forcing {Shanks and Roegner 2007}. Since 1960, annual landings provide a reasonable notion of abundance of legal-sized males because in many years fisheries catch 80 to 90 percent of all available legal-sized males {Leet et al. 2001}. Females must be discarded and are rarely caught since they generally do not exceed the minimum carapace width, but they may be experiencing reduced egg production (potentially 2-25%) as females mate with males larger than themselves and the fishery is removing a large portion of large males {Leet et al. 2001}{Hankin et al. 1997}. There is no evidence that the stock is above or below reference points and the inherent vulnerability is low, therefore the stock status is of moderate concern. 2.3 - Fishing Mortality 5.00 Very Low There is no stock assessment with reference points, but the main fishery for dungeness crab (pot fishery) caught 1,539 mt in 2009-10 season, 8,666 mt in the 2010-11 season, and 7,013 mt in the 2011-12 season south of the Mendocino/Sonoma county line {CDFG 2011b}. Catch is highly variable, but has not been less than 420 mt south of the Mendocino/Sonoma county line since the 1993-94 season {CDFG 2011b}. Dungeness crab are not found south of Santa Barbara {Leet et al. 2001}. Catch in the California halibut bottom trawl fishery, where 100% is discarded, was 9.6 mt in 2009, 18.1 mt in 2010, and 60.7 mt in 2011 {NWFSC 2012}. The dungeness crab catch in the California halibut bottom trawl fishery represents 0.6%, 0.2%, and 0.9% of the pot fishery in 2009, 2010, and 2011, respectively. Therefore it is evident that the California halibut bottom trawl fishery is not a substantial contributor to dungeness crab fishing mortality and is of very low concern.
26 2.4 - Discard Rate The discard rate is the sum of all dead discards (i.e. non-retained catch) plus bait use divided by the total retained catch. 0.90 40-60% The California halibut discard to landings ratio were 81%, 74%, and 76% for 2009, 2010, and 2011 respectively {NWFSC 2012}. Fifty percent or more of the discards were dungeness crab {NWFSC 2012} which likely have high post-release survival rates. Dungeness crab mortality from trawls off Washington are estimated at 2% for hardshelled crabs and 9% for softshelled crabs {Alverson et al. 1994}. Therefore approximately 10% of the discarded dungeness crabs do not survive. The California discard to landings ratio excluding crab were 39%, 32%, and 36% for 2009, 2010, and 2011 respectively. Adding 10% mortality of dungeness crabs results in a discard to landings ratio between 40 and 60%. Humpback Whale: California/Oregon/Washington 2.1 - Inherent Vulnerability California: Southern Northeast Pacific, Gillnet, Bottom 1.00 High Humpback whale, Megaptera novaeangliae, as all marine mammals, has a high inherent vulnerability. 2.2 - Stock Status California: Southern Northeast Pacific, Gillnet, Bottom 1.00 Very High Humpback whale has been listed as endangered on the endangered species list since 1970 {NMFS 2012b}, therefore it is of very high conservation concern. 2.3 - Fishing Mortality California: Southern Northeast Pacific, Gillnet, Bottom 3.67 Low
27 Humpback whales have a PBR allocation for US waters of 11.3 whales per year {Carretta et al 2013}. Eighteen whales were observed entangled, alive or dead, in fishing gear from 2004-2008, but none were observed in known California halibut gillnets {Carretta et al 2013}. Seven were observed entangled in unknown fishing gear that may have included California halibut gillnets with greater than or equal to 1.4 whales taken annually with unknown fishing gear {Carretta et al 2013}. This species is still listed as endangered therefore it is automatically a strategic stock under the marine mammal protection act (MMPA), however it is not experiencing cumulative fishing mortality in excess of PBR {Carretta et al 2013}. The estimated annual mortality and serious injury due to entanglement is 3.2 per year from commercial fisheries, which is less than the allowed PBR (11.3), but greater than 10% of the PBR; therefore total fishing mortality is not approaching zero, which is the goal {Carretta et al 2013}. The California halibut gillnet fishery is considered a category two fishery based on its effects on this stock {NMFS 2012a}. Based on the category two ranking, a take in the fishery of between 10-50% of the PBR (conservatively allocating all takes from unknown fishing gear to this fishery), and the fact that the cumulative fishing mortality is less than PBR, humpback whales have a low conservation concern in the California halibut gillnet fishery. Rationale: A category two fishery in the NOAA list of fisheries means that the fishery has occasional interactions with marine mammals {NMFS 2012a}. The list of fisheries documented one humpback whale as seriously injured in 2007, which equals 1.7% of stock's PBR of 11.3 {NMFS 2012a}. Assigning all unknown entanglement mortalities and serious injuries to the California halibut gillnet fishery is very conservative. 2.4 - Discard Rate The discard rate is the sum of all dead discards (i.e. non-retained catch) plus bait use divided by the total retained catch. California: Southern Northeast Pacific, Gillnet, Bottom 0.95 20-40% The discards to landings ratio for gillnet fisheries worldwide are estimated to be an average rate of 10% or a weighted rate 0.5% {Kelleher 2005}. Gillnets worldwide (both surface and bottom) account for less than 30,000 mt of discards with reported landings of over 3 million mt {Kelleher 2005}. This may not be exactly the ratio specific to the California halibut gillnet fishery, but fishery specific data are not available. A study of bycatch in small-scale (vessels less than 15 m) fisheries in Baja California, Mexico calculated a discards to landings ratio of 34.3% by weight {Shester and Micheli 2011}. The conservative discards to landings ratios is 20 to 40%. Rationale: The weighted discard rate is considered to be the most accurate and representative at a global level
28 {Kelleher 2005}. Longnose Skate: Pacific Coast 2.1 - Inherent Vulnerability California: Southern Northeast Pacific, Trawl, Bottom 2.00 Medium The longnose skate, Raja rhina, has a vulnerability score of 55 out of 100 {Froese and Pauly 2013}, therefore it has moderate inherent vulnerability. 2.2 - Stock Status California: Southern Northeast Pacific, Trawl, Bottom 4.00 Low Longnose skate is considered one stock along the U.S. West coast and was assessed in 2008 {Gertseva and Schirripa 2008}. The unexploited spawning stock biomass is estimated at 7,034 mt {Gertseva and Schirripa 2008}. The estimated spawning stock biomass at the beginning of 2007 was 4,634 mt, which is 66% of the unfished stock level {Gertseva and Schirripa 2008}. The management target is 40% of the unexploited biomass, and the overfished threshold is 25% of the unexploited biomass {Gertseva and Schirripa 2008}. For 2013, longnose skate is classified as not overfished and not approaching overfished condition by the National Marine Fisheries Service (NMFS) {NMFS 2013b}. The spawning stock biomass is estimated above the management target, but since a more recent stock assessment is unavailable the stock status is of low conservation concern. 2.3 - Fishing Mortality California: Southern Northeast Pacific, Trawl, Bottom 3.67 Low
29 The MSY proxy harvest rate for longnose skate is spawning potential rate (SPR) = F45%, which corresponds to an exploitation rate of 4.3% {Gertseva and Schirripa 2008}. The exploitation rate estimated in 2007 is 1.25%, with the all-time high of 4.02% in 1981 {Gertseva and Schirripa 2008}. The harvest recommendations for 2013 and 2014 are either to take no action or to increase the annual catch limit, both of which would maintain the stock at a healthy level {PFMC and NMFS 2012} according to the 2008 assessment. The stock is classified as not experiencing overfishing in 2013 {NMFS 2013b} with catches calculated based on the 2008 assessment. The lack of a recent assessment to confirm sustainable fishing mortality results in a low conservation concern in the California halibut fishery. Rationale: The exploitation rate equals total catch divided by estimated total biomass and F45% is considered to be an appropriately precautionary level of fishing mortality for a SPR-based proxy according to the Seafood Watch criteria. 2.4 - Discard Rate The discard rate is the sum of all dead discards (i.e. non-retained catch) plus bait use divided by the total retained catch. 0.90 40-60% The California halibut discard to landings ratio were 81%, 74%, and 76% for 2009, 2010, and 2011 respectively {NWFSC 2012}. Fifty percent or more of the discards were dungeness crab {NWFSC 2012} which likely have high post-release survival rates. Dungeness crab mortality from trawls off Washington are estimated at 2% for hardshelled crabs and 9% for softshelled crabs {Alverson et al. 1994}. Therefore approximately 10% of the discarded dungeness crabs do not survive. The California discard to landings ratio excluding crab were 39%, 32%, and 36% for 2009, 2010, and 2011 respectively. Adding 10% mortality of dungeness crabs results in a discard to landings ratio between 40 and 60%. California: Southern Northeast Pacific, Trawl, Bottom 0.95 20-40% The California halibut discard to landings ratio overall were 81%, 74%, and 76% for 2009, 2010, and 2011 respectively {NWFSC 2012}. Fifty percent or more of the discards were dungeness crab {NWFSC 2012} which do not occur south of Point Conception. Therefore the discard to landings ratio excluding dungeness crabs were 39%, 32%, and 36% for 2009, 2010, and 2011 respectively {NWFSC 2012}. These values fall between a 20-40% discard to landings ratio.
30 Skates 2.1 - Inherent Vulnerability California: Southern Northeast Pacific, Gillnet, Bottom 1.00 High There are five common skate species that overlap with the California halibut distribution: big, Beringraja binoculata, sandpaper, Bathyraja interrupta, California, Raja inornata, longnose, R. rhina, and starry, R. stellulata skates. The vulnerability scores of these species are 86, 59, 53, 55, and 53 {Froese and Pauly 2013}. This group conservatively has high inherent vulnerability. 2.2 - Stock Status California: Southern Northeast Pacific, Gillnet, Bottom 2.00 High Within the unspecified skate category only one species has a stock assessment. The longnose skate was assessed in 2008 and the stock was estimated at 66% of the unfished stock level in 2007 {Gertseva and Schirripa 2008}, but a more recent stock assessment is unavailable. The other four species have unknown stock statuses. The generally unknown statuses in combination with the high inherent vulnerability of this group results in a high conservation concern. 2.3 - Fishing Mortality California: Southern Northeast Pacific, Gillnet, Bottom 3.67 Low The fishing mortality for this unspecified skate category is unknown because no reference points have been estimated and the stocks have not been assessed. The one species, the longnose skate, with a stock assessment has a MSY proxy harvest rate that corresponds to a 4.3% exploitation rate; the exploitation rate estimated for 2007 was 1.25% {Gertseva and Schirripa 2008}. The longnose skate is of very low conservation concern. The California halibut gillnet fishery is not the main fishery for this species, 97% of skate landings are from bottom trawl {Gertseva and Schirripa 2008}. Thus, since the gillnet fishery is not one of the primary anthropogenic contributors to mortality and does not target unspecified skates, they are of low concern.
31 2.4 - Discard Rate The discard rate is the sum of all dead discards (i.e. non-retained catch) plus bait use divided by the total retained catch. California: Southern Northeast Pacific, Gillnet, Bottom 0.95 20-40% The discards to landings ratio for gillnet fisheries worldwide are estimated to be an average rate of 10% or a weighted rate 0.5% {Kelleher 2005}. Gillnets worldwide (both surface and bottom) account for less than 30,000 mt of discards with reported landings of over 3 million mt {Kelleher 2005}. This may not be exactly the ratio specific to the California halibut gillnet fishery, but fishery specific data are not available. A study of bycatch in small-scale (vessels less than 15 m) fisheries in Baja California, Mexico calculated a discards to landings ratio of 34.3% by weight {Shester and Micheli 2011}. The conservative discards to landings ratios is 20 to 40%. Rationale: The weighted discard rate is considered to be the most accurate and representative at a global level {Kelleher 2005}. White Shark 2.1 - Inherent Vulnerability California: Southern Northeast Pacific, Gillnet, Bottom 1.00 High White sharks, Carcharodon carcharias, have an inherent vulnerability of 86 out of 100 {Froese and Pauly 2013}, therefore it has a high inherent vulnerability. 2.2 - Stock Status California: Southern Northeast Pacific, Gillnet, Bottom 2.00 High There is no stock assessment available for white sharks, therefore there are no reference points to use to assess the stock status. The population size has been estimated at 219 mature and sub-adults for central California {Chapple et al. 2011}, but there are no historic estimates to compare this to. There has