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Fact Sheet Title Fact Sheet |
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Flathead grey mullet - USA Louisiana |
| Data Ownership | This document provided, maintained and owned by Food and Agriculture Organization (FAO) , is part of WECAFC Stock Status Reports data collection. |
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ident Block | ident Block![tree map display tree map](/fi/figis/assets/images/factsheets/addinfo.gif) | | Species List: | Species Ref: en - Flathead grey mullet, fr - Mulet à grosse tête, es - Pardete, zh - 鲻 |
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| ident Block Flathead grey mullet - USA Louisiana
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Large Marine Ecosystem Areas (LME) |
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5 | Gulf of Mexico |
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Aq Res | Biological Stock: Yes
Value: National Management unit: Yes
Reference year: 2014
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Considered a management unit: An aquatic resource or fishery is
declared as [Fishery] Management Unit if it is
effectively the focus for the application of selected
management methods and measures, within the broader
framework of a management system. According to the FAO
Glossary for Responsible Fishing, "a Fishery Management
Unit (FMU) is a fishery or a portion of a fishery
identified in a Fishery Management Plan (FMP) relevant
to the FMP's management objectives." FMU's may be
organised around fisheries biological, geographic,
economic, technical, social or ecological dimensions ,
and the makeup and attribute of a fishery management
unit depends mainly on the FMP's management
objectives. |
Jurisdictional distribution: Jurisdictional qualifier (e.g.
"shared", "shared - highly migratory") of the aquatic
resource related with its spatial distribution. |
Environmental group: Classification of the aquatic
resource according to the environmental group (e.g.
pelagic invertebrate, or demersal fish) to which the
species belong. |
Reference Year: The Reference Year is the last year considered in the stock assessment and/or fishery status. |
| | | | Aq Res State Trend For the state of Louisiana assessment results indicated that the grey mullet stock was neither overfished nor experiencing overfishing. Habitat Bio Climatic Zone: Tropical; Temperate. Vertical Dist: Demersal. Water Area Overview ![](/fi/figis/assets/images/addinfo_black.gif) | Water Area Overview Flathead grey mullet - USA Louisiana
Large Marine Ecosystem Areas (LME) | 5: Gulf of Mexico |
| | | | Water Area Overview
| | | | Water Area Overview |
Water Area OverviewFlathead grey mullet - USA Louisiana Aq Res Struct Biological Stock: Yes Bio Assess Uncertainty: Intermediate Data The model is fit to the data with a maximum likelihood fitting criterion. Minimum data requirements are fishery catch-at-age and an index of abundance (IOA). Landings values are taken from the Louisiana Department of Wildlife and Fisheries (LDWF) Trip Ticket Program and the National Marine Fisheries Service (NMFS) commercial statistical records. Indices of abundance are developed from the LDWF experimental marine gillnet survey. Age composition of fishery and survey catches are estimated with age-length keys derived from samples directly of the fishery and a von Bertalanffy growth function. Assess Models Type: Age-structured Age-Structured Assessment Program A statistical catch-at-age model is used in this assessment to describe the dynamics of the Louisiana striped mullet stock (1996-2014). This model uses a maximum likelihood fitting criterion to project population size from abundance estimates in the initial year and recruitment estimates in subsequent years. ASAP is a statistical catch-at-age model that allows internal estimation of a BevertonHolt stock recruitment relationship and MSY-related reference points. (ASAP3 Version 3.0.12; NOAA Fisheries Toolbox http://nft.nefsc.noaa.gov). Results Abundance, Recruitment, and Spawning Stock - Total stock size and abundance at age estimates from the base model are presented in Table 14. Stock size has varied over the time-series. Stock size decreased from 29.2 million females in 1996 to a minimum of 9.5 million females in 2005. Since 2005, stock size increased to a peak of 24.8 million females in 2012. The 2014 estimate of stock size is 20.9 million females. Recruitment estimates from the base model are presented in Figure11. Recruitment has varied over the time-series. Age-1 recruit estimates decreased from 11.5 million fish in 1996 to 3.8 million age-1 fish in 2005. Since 2005, recruitment increased to a peak of 14.6 million age-1 fish estimated in 2012. The 2014 estimate of age-1 recruits is 6.3 million age-1 females. Spawning stock estimates (total egg production) are presented in Figure 12. Spawning stock has varied over the time series with a decreasing trend in early years to an increasing trend in later years. Spawning stock decreased from 4.9 trillion eggs in 1996 to a minimum of 1.9 trillion eggs in 2007. Since 2007, the trend has been upward with an estimate of 5.9 trillion eggs in 2014. - Fishing Mortality - Estimated fishing mortality rates are presented in Table 15 (apical, average, and age-specific) and Figure 13 (average only). Average fishing mortality has varied over the time-series with an overall decreasing trend. The highest estimates of F were in earlier years of the time series with peaks observed in 1999 and 2004 (0.29 and 0.32 yr-1 ). Since 2004, average fishing mortality rates decreased to a minimum of 0.01 yr-1 in 2009 and has remained low. The 2014 estimate of average F is 0.03 yr-1. - Stock Status - The history of the LA striped mullet stock relative to F/F30% and SS/SS30% is presented in Figure 17. Given the established conservation standard of 30% SPR, fishing mortality rates exceeding F30% (F/F30%>1.0) are defined as overfishing; spawning stock sizes below SS30% (SS/SS30 %< 1.0) are defined as the overfished condition. - Overfishing Status - Using results of the ASAP model presented in this assessment, the current estimate of F/F30% is <1.0, suggesting the stock is currently not undergoing overfishing. However, the assessment model indicates that the stock did experience overfishing in earlier years of the time-series. - Overfished Status - The current estimate of SS/SS30% is >1.0, suggesting the stock is currently not in an overfished state. However, the assessment model indicates that the stock was in an overfished state in earlier years of the time-series. Sci Advice Research and Data Needs - • As with any analysis, the accuracy of this assessment is dependent on the accuracy of the information of which it is based. Mapes et al. (1998) identify several areas for research to address. Below we list additional recommendations to improve future LA assessments of striped mullet. • Only limited age data are available from the LDWF marine gillnet survey. Ages of survey catches in this assessment were assigned from a von Bertalanffy growth function. Age samples collected directly from the survey in question would allow a more accurate representation of survey age composition in future assessments. • Methods to characterize fishery catch at age for years prior to 1996 need to be examined. Inclusion of years prior to the 1995 peak in commercial striped mullet landings in the assessment model should provide better contrast in spawning stock size and allow more certainty in reference point estimation. • Factors that influence year-class strength of striped mullet are poorly understood. Investigation of these factors, including inter-annual variation in seasonal factors and the influence of environmental perturbations such as the Deepwater Horizon oil spill, could elucidate causes of inter-annual variation in abundance, as well as the species stock-recruitment relationship. • Fishery-dependent data alone is not a reliable source of information to assess status of a fish stock. Consistent fishery-dependent and fishery-independent data sources, in a comprehensive monitoring plan, are essential to understanding the status of fishery. A new LDWF fishery-independent survey methodology was implemented in 2013. This methodology should be assessed for adequacy with respect to its ability to evaluate stock status, and modified if deemed necessary. • With the recent trend toward ecosystem-based assessment models, more data is needed linking striped mullet population dynamics to environmental conditions. The addition of meteorological and physical oceanographic data coupled with food web data may lead to a better understanding of the striped mullet stock and its habitat. Management Management unit: Yes Sources 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. http://www.fao.org/fi/static-media/MeetingDocuments/WECAFC/SAG2018/3e.pdfWest, J., Decossas G. &amp; Powers, J. 2016a. Update Assessment of Striped Mullet Mugil cephalus in Louisiana Waters 2016 Report. Louisiana Department of Wildlife and Fisheries, 38 pp. http://www.wlf.louisiana.gov/sites/default/files/pdf/document/40572-stock/mullet_la_2016.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. http://www.fao.org/3/ca4776t/ca4776t.pdfAll references to figures, tables and bibliography in the text are found within the source of information. |
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