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Fishery Assessment of Sardine Stock GSA01 (Northern Alboran)

Fishery Assessment of Sardine Stock GSA01 (Northern Alboran). Bellido, J.M. 1 , Quintanilla, L. 2 , Giráldez, A. 2 , Torres, P 2 ., Ceruso, C. 1 , Alemany, F. 3 , Iglesias, M. 3

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Fishery Assessment of Sardine Stock GSA01 (Northern Alboran)

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  1. Fishery Assessment of Sardine Stock GSA01 (Northern Alboran) Bellido, J.M.1, Quintanilla, L.2, Giráldez, A.2, Torres, P2., Ceruso, C.1, Alemany, F.3, Iglesias, M.3 1 Instituto Español de Oceanografía. Centro Oceanográfico de Murcia. C/ Varadero 1. San Pedro del Pinatar. 30740. Murcia. Spain. 2 Instituto Español de Oceanografía. Centro Oceanográfico de Málaga. Puerto Pesquero s/n. Apdo 285. Fuengirola. 29640. Málaga. Spain. 3 Instituto Español de Oceanografía. Centro Oceanográfico de Baleares. Muelle del Poniente s/n. Apdo 291. Palma de Mallorca 07015. Spain. Sardine GSA01 Bellido et al

  2. Introduction • Fishery assessment by VPA methods of the Spanish sardine stock GSA01. • VPA Lowestoft software suite was used and XSA was the assessment method. A separable VPA was also run as exploratory analysis for both stocks. • Stochastic short term projections were also produced. Sardine GSA01 Bellido et al

  3. GFCM GSA-01 Northern Alboran Landings and sampling ports (in blue) Sardine GSA01 Bellido et al

  4. Assessment Data GSA01 • Landings time series 2000-2007. • ALK 2003-2006, combined ALK for 2000-2002. Length Distributions 2003-2007, combined for 2000-2002. • Biological sampling 2003-2007 for Maturity at age and Weight-Length relationships. • Tuning data from acoustic survey ECOMED and Commercial Fleet off Estepona, Málaga and Adra. Sardine GSA01 Bellido et al

  5. XSA Input Data GSA01 Sardine GSA01 Bellido et al

  6. XSA Input Data GSA01 Sardine GSA01 Bellido et al

  7. Assessment Model • Separable VPA – as Exploratory tool. • VPA - XSA (Extended Survivors Analysis) as assessment tool. Sardine GSA01 Bellido et al

  8. Diagnostics Separable GSA01 Log catchability residual plots. Some conflict between ages seem to appear. Fleet behaviour and fishery movements could affect the catchability pattern. Sardine GSA01 Bellido et al

  9. XSA Assessment • Main Settings XSA: • Fbar 1-3. • Age 2 for q stock-size independent and age 3 for q independent of age. • Fshrinkage = 0.500 and S.E. for fleet terminal estimates ≥ 0.300 • XSA Diagnostics. • Residuals by Fleet. • Estimations of Survivors by age and fleet. Sardine GSA01 Bellido et al

  10. Fleet Diagnostics GSA01 Minimun (from ECOMED) Maximun (from ECOMED) Minimun (from ECOMED) Maximun (from ECOMED) Minimun (from ECOMED) Maximun (from ECOMED) Sardine GSA01 Bellido et al

  11. Estimated Survivors by Fleet GSA01 Sardine GSA01 Bellido et al

  12. Estimated Survivors by Fleet GSA01 Sardine GSA01 Bellido et al

  13. Estimated Survivors by Fleet GSA01 Sardine GSA01 Bellido et al

  14. Results – Stock Summary GSA01 Sardine GSA01 Bellido et al

  15. Short term projections • Deterministic Projections for three years (2008 to 2010). • MFDP software (Multi-Fleet Deterministic Projections). Settings: • Recruitment Geometric mean: • GSA01 - R2007 = 228 millions. • F statu quo is Fishing Mortality Average last three years and Reference ages 1-3, i.e. average Fbar last 3 years. • GSA01 – Fstatu quo = 0.28. Sardine GSA01 Bellido et al

  16. Results GSA01 Short term projection Sardine GSA01 Bellido et al

  17. Conclusions - Assessment • Landings decrease in 2007, reaching up 6,770 t. The time series shows a rather fluctuating trend, with the lowest value in 2004 (3,960 t) and the greatest in 2006 (10,000 t). • Fishing mortality is at a moderate level (F07=0.26), showing a rather stable trend. • Recruitment in 2007 decreases from that of previous years (R07=228 millions), showing the lowest value of the time series. The time series recruitment shows a decreasing pattern. • Both Total biomass in 2007 (TB=32,300 t ) and Spawning Stock Biomass in 2007 (SSB=28,800 t) decrease with respect to 2006, although they are still over the lowest SSB in 2000 (Bloss=22,100 t). Sardine GSA01 Bellido et al

  18. Conclusions – Catch Forecasting • statu quo F (Fbar05-07=0.28) and (R07=228 mill): • landings are predicted to be 5,800 t in 2008 and 5,000 t in 2009 t. • Total biomass will decrease from 27,400 t in 2008 to 21,600 t in 2010 • SSB will also decrease from 23,700 t in 2008 to 18,000 t in 2010. • This exploitation pattern of maintaining F statu quo 2008-10, with scenarios of low recruitment rates, could prompt a decline of the fishery with SBB scenarios under current Bloss. • In this situation it is particularly important to pay special attention to recruitment levels as they could prompt sudden increases or drops in a near future. Sardine GSA01 Bellido et al

  19. Conclusions - Management considerations • No reference points can be suggested at this point. Further years will come an extension of the assessment time series suitable to suggest Reference Points and Harvest Control Rules. • This fishery is considered as fully exploited. • Under this scenario we consider fishing effort should not increase beyond the current levels. This should allow not to increase (or at least to maintain) the current levels of Fishing mortality. Sardine GSA01 Bellido et al

  20. Further work • Reference points. • Harvest Control Rules. Sardine GSA01 Bellido et al

  21. Thanks for your attention. Comments are welcomed. Dr. Jose Mª Bellido (josem.bellido@mu.ieo.es) Sardine GSA01 Bellido et al

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