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American cupped oyster - USA Louisiana
Marine Resource  Fact Sheet
Status of stocks and resources 2019
American cupped oyster - USA Louisiana
Fact Sheet Citation  
Owned byFood and Agriculture Organization (FAO) – More
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Species:
FAO Names: en - American cupped oyster, fr - Huître creuse américaine, es - Ostión virgínico
Geographic extent of American cupped oyster - USA Louisiana
Main Descriptors
Considered a single stock: Yes        Spatial Scale: National
Management unit: Yes        Reference year: 2014
 
 
Biological State and Trend
State & Trend Descriptors
FIRMS
Exploitation rateNot applicable
Abundance levelNot applicable
FAO Categories
Exploitation stateOverfished

Biomass estimates of American cupped oysters in Louisiana, which accounts for most of the landings from the USA in Area 31, indicate resource overexploitation. 
Habitat and Biology
Climatic zone: Tropical.   Depth zone: Coastal (0 m - 50 m).   Horizontal distribution: Estuarine.   Vertical distribution: Benthic.  

Water Area Overview
Spatial Scale: National

Geo References
Resource Structure
Considered a single stock: Yes
Assessment
Level of uncertainty: Intermediate

Data

Data up to 2014. Landings from Louisiana represent approximately 14% of total landings in FAO Area 31. Public oyster beds in Louisiana at 34% of target biomass. Total USA landings at 10% of average maximum landings in 2016.
Assessment Model
Type:  Others
Biological Evaluation

This biological evaluation includes using SCUBA to collect oyster samples from within a square meter frame from multiple locations (sample stations) in each public oyster ground. At each station, five replicate square-meter quadrat samples are collected and data is combined to produce average numbers of spat, seed, and sack oysters per station. Recent cultch plants (less than 2 oyster seasons old), however, are typically sampled by collecting five random ¼ metersquare quadrat samples. A total of 110 sample stations were visited by Louisiana Department of Wildlife and Fisheries (LDWF) biologists during the 2015 assessment and 550 individual samples were gathered. Sampling data are presented by Coastal Sampling Area (CSA). During the 2015 stock assessment sampling, Coastal Study Area 1 South had the most sample stations (31) while CSA 5 East held the fewest (3). A higher density of sampling occurs in the Black Bay (CSA 1 South) and Sister Lake (CSA 5 West) areas due to their high level of oyster production in past years and historical importance to the oyster industry. During the 2015 assessment, 10 of the 110 stations were located on newly-constructed cultch plants (cultch plants constructed since 2011).
Overall Assessment Results

Annual Stock Size - The statewide oyster stock size in 2015 decreased over 2014 levels as approximately 1,115,484 (±323,384) barrels of oysters (1 barrel of oysters approximately 70 kg) are available on the public oyster areas of Louisiana this year (Table 1). Unfortunately, this stock size represents an approximate decrease of 40% from 2014 levels, and the comparison of the two estimates shows a significant statistical difference. The 2015 statewide stock availability, just as in 2014, is heavily influenced by oyster stocks in the Mississippi Sound area (CSA 1), but still remains well below the long-term mean of 3.29 million barrels (Figure 4). Both seed and market-size oyster stocks decreased by approximately 40% statewide (Figure 5), and seed oyster stocks were below 2014 levels in all CSAs. Market-size oyster stocks showed increases in CSAs 1, 3, 5E, and 5W. The oyster stock in CSA 1-North showed an approximate 14% decrease in size compared to 2014 at 508,468 (±236,715) barrels. This decrease was driven largely by a reduction in seed oyster stocks which fell 23% over 2014 levels to 336,732 (±101,577) barrels; however seed stock size is 26% above the 10-year mean. The market-size oyster stock is estimated to be 171,735 (±53,329) barrels, an increase of approximately 12% compared to 2014 and largest the market stock size since 2009; however market stock size is 5% below the 10-year mean. The largest contributor to the seed oyster stock is the Three-Mile Pass 2013 cultch plant (41%), and the Drum Bay 2013 cultch plant contributed most to the market-size oyster stock (46%). Oyster production on public grounds in CSA 1-South appears to be seriously impaired. The current oyster stock size is only 50,631 (±22,285) barrels, down 41% compared to 2014 and down 96% from the long-term mean. This decrease was driven by an 83% reduction in the seed oyster stock compared to 2014, estimated at only 5,059 (±1,868) barrels. The market-size oyster resource showed a 19% decrease compared to 2014, estimated at only 45,572 (±20,418) barrels. Alarmingly, no spat or seed oysters were found on any reef complexes; seed oysters were only found on the Lake Fortuna 2012 cultch plant (which contained no spat). Only four of the twelve reef complexes were estimated to have any oyster resource. The current oyster stock size in the Hackberry Bay Public Oyster Seed Reservation (CSA 3) is 17,663 (±6,344) barrels; a 52% decrease in total stock size compared to 2014. Seed oyster availability in 2015 decreased 74% to 9,267 (±3601) barrels and is 14% below the 10-year mean; however the market-size oyster stock size increased 371% to 8,397 (±2,743) barrels and is 144% above the 10-year mean. The size of the oyster stock in the Sister Lake Public Oyster Seed Reservation in 2015 decreased 34% compared to 2014 levels and is estimated at 198,952 (±18,152) barrels. The seed oyster stock decreased 48% to 141,034 (±9,912) barrels, but is only slightly below the long-term mean (6%). The market-size oyster stock increased 73% to 57,919 (±4,998) barrels; however this is 50% below the long-term mean. The Sister Lake 2012 cultch plant continues to be productive, containing 88% of the available seed resource and 85% of the available market-size oyster resource. Public oyster areas in CSA 7 (Calcasieu and Sabine Lakes) accounted of over 30% of the statewide oyster resource in 2015 (Table 1, Figure 6) and the oyster stock size in Sabine Lake (258,527 ± 31,106 barrels) is over three times greater than Calcasieu Lake (77,604 ± 10,424 barrels). The oyster stocks in Sabine and Calcasieu both decreased in 2015 compared to 2014. Seed and market-size oyster stocks in Sabine Lake fell 40% (77,728 ± 9,227 barrels) and 64% (180,799 ± 21,880 barrels) respectively, and seed and market-size oyster stocks in Calcasieu Lake fell 66% (41,918 ± 4,974 barrels) and 62% (35,685 ± 5,451 barrels) respectively. - 2014-2015 Commercial Harvest Season - Estimated commercial harvest increased during the 2014/2015 oyster season (Table 2) as compared to the previous season and was largely due to the successful oyster season in the Mississippi Sound area (CSA 1 North) where a strong 2014 fall spat set and 5-day 2015 spring season yielded 111,434 barrels of seed oysters and 16,372 sacks of market oysters. This equates to a 20-fold increase in total harvest for the Mississippi Sound area compared to the previous season. The overall decrease in market oyster harvest can be attributed to the typical biannual closure of the Sister Lake POSR and the closure of the Hackberry Bay POSG during the 2014/2015 season. Increased market oyster harvest was observed in CSA6 and Calcasieu Lake. The Louisiana Department of Health and Hospitals opened Harvest Area 25 in CSA6 which resulted in 30,051 sacks of market oysters (almost a 10-fold increase compared the previous season). Harvest in Calcasieu Lake was again restricted to the West Cove portion of the lake, yet harvesters were able to produce over 55,000 sacks of market oysters during the 2014/2015 season (almost a 40% increase compared to the previous season).
Management
Management unit: Yes
Source of information
 
FAO. Western Central Atlantic Fishery Commission. 2019. Review of the state of fisheries and fisheries resources in the WECAFC region. Meeting document WECAFC/SAG/IX/2018/3 of the ninth session of the Scientific Advisory Group, Christ Church, Barbados, 19-20 November 2018.  Click to openhttp://www.fao.org/fi/static-media/MeetingDocuments/WECAFC/SAG2018/3e.pdf
Louisiana Wildlife and Fisheries. 2015. 2015 Oyster Stock Assessment Report of the Public Oyster Areas of Louisiana. Seed Grounds and Seed Reservations. Oyster Data Report Series No. 21. 116 pp.  Click to openhttp://www.wlf.louisiana.gov/sites/default/files/pdf/page/37756-stock-assessments/2015oysterstockassessment.pdf
Bibliography
 
FAO. Western Central Atlantic Fishery Commission/FAO Commission des pêches pour l’Atlantique Centre-Ouest/FAO Comisión Central de Pesca para el Atlántico CentroOccidental. 2019. Report of the ninth session of the Scientific Advisory Group, Christ Church, Barbados, 19-20 November 2018. Rapport de la neuvième session du Groupe scientifique consultatif, Christ Church, Barbade, 19-20 Novembre 2018. Informe de la octava sesión del Grupo Asesor Científico, Christ Church, Barbados, 19-20 de Noviembre de 2018. FAO Fisheries and Aquaculture Report/Rapport sur les pêches et l’aquaculture/Informe de Pesca y Acuicultura. No. 1266. Bridgetown, 156 pp.  Click to openhttp://www.fao.org/3/ca4776t/ca4776t.pdf
All references to figures, tables and bibliography in the text are found within the source of information.
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