The Experts below are selected from a list of 8403 Experts worldwide ranked by ideXlab platform
Doug S Butterworth - One of the best experts on this subject based on the ideXlab platform.
-
developing and refining a joint management procedure for the multispecies south african Pelagic Fishery
Ices Journal of Marine Science, 2004Co-Authors: J A A De Oliveira, Doug S ButterworthAbstract:Pilchard (sardine) and anchovy are the main targets of South Africa’s Pelagic Fishery. This Fishery is the country’s second most valuable in monetary terms, and produces the highest annual yield in terms of landed mass (in recent years, a combined catch of the order of 400 000 t). It is the most dynamic of South Africa’s main commercial fisheries, because the species targeted are relatively short-lived, often occur in mixed shoals, and experience large fluctuations in abundance. Mixed shoaling causes operational problems for the Fishery, because of the inevitability of juvenile pilchard bycatch (of more value as adults for canning) in the anchovy-directed Fishery. This operational interaction implies a trade-off between allowable catches for the two species, and hence necessitates that they are managed together. The development of a joint ‘‘management procedure’’ (sensu IWC) for the two species is described. This provides a framework for quantifying this trade-off, subject to the constraint that acceptable levels of risk of ‘‘collapse’’ are not exceeded for either resource. Important new features incorporated in a revision of the procedure implemented in 2002, which have made appreciably enhanced catches from the resources possible, are described.
Abdussamad E M - One of the best experts on this subject based on the ideXlab platform.
-
Account of Large Pelagic Fishery of Maharashtra
ICAR - Central Marine Fisheries Research Institute, 2021Co-Authors: Chellappan Anulekshmi, Nakhawa A D, Khandagale P A, Mini K G, Abdussamad E MAbstract:Large Pelagic fishes are one of the preferred fishes in domestic and international trade. Information on their distribution, abundance and stock status are limited from the Maharashtra coast. Nine major groups are contributing to the Fishery in Maharashtra and the major share is of seerfishes ( 38%). Gillnets contribute 48% of the landings of large Pelagics. This group contributed 14% of the total Pelagic fish landings during 2007-2019 period with August to December as the months of peak landing, contributing about 63% of the annual landings
-
Fishery for the Large Pelagic resources in Gujarat
ICAR - Central Marine Fisheries Research Institute, 2021Co-Authors: Abdul Azeez P, Rohit Prathibha, Mini K G, Koya Mohammed, Abdussamad E MAbstract:Large Pelagic Fishery resources contributed about 4% of total marine fish landing in Gujarat. Tunas dominated among LP resources, followed by seerfishes, queenfish and dolphinfish. They are targeted by mechanized gillnetters and the multiday trawlers with region between Veraval and Porbander as the major fishing zones. Mainly limited to the shelf areas within 200 m depth, the operations extended to oceanic areas beyond 200m during summer months. Poor handling and onboard storage effect the quality of the fishes and market value realised by the fishers. Mainly dried products of LP are traded within the country as well as abroad like Sri Lanka, Tunisia and Thailand
-
Trends of large Pelagic Fishery in Goa
ICAR - Central Marine Fisheries Research Institute, 2020Co-Authors: Rajesh K M, Rohit Prathibha, Abdussamad E MAbstract:The large Pelagic fish catch in Goa over the decade varied from 3,095 t in 2011 to 13,247 t in 2013. Their percentage contribution to the total large Pelagic fish landings of the country ranged from 1.4 in 2016 & 2018 to 7.0 in 2013. Purse seine is the major gear targeting large Pelagic fishes such as tunas, seerfishes, barracudas and queenfishes. Fishery trends, crafts and gears involved in exploitation, seasonal pattern of landings, species composition, onboard handling and preservation of large Pelagic fishes landed in Goa are described
-
Status of large Pelagic Fishery in Karnataka
ICAR - Central Marine Fisheries Research Institute, 2020Co-Authors: Rajesh K M, Rohit Prathibha, Abdussamad E MAbstract:Tunas, seerfishes, barracudas, queenfishes and fullbeaks are the major large Pelagic fishes landed along Karnataka Coast, while, landings of cobia, dolphinfish, billfishes and rainbow runner are limited. The Fishery trends, crafts and gears operated to tap large Pelagics, seasonal pattern of landings, species composition and post- harvest utilization and market chains in Karnataka is detaile
-
Status and prospects of Large Pelagics Fishery in Tamil Nadu and Puducherry
ICAR - Central Marine Fisheries Research Institute, 2020Co-Authors: Sivadas M, Mini K G, Margaret Muthu Rathinam A, Vinothkumar R, Abdussamad E MAbstract:The status of the landing of large Pelagic Fishery including the resource-wise contribution and their species composition in Tamil Nadu and Puducherry is presented based the on the estimated fish landings data for the period 2007-2019. The large Pelagics landing in Tamil Nadu varied from 30,659 t to 83,620 t with an average of 45,330 t. In Puducherry, it varied from 254 t to 5,453 t with an average of 2,515 t. Various crafts and gears involved in the Fishery are described while the future prospects and management issues are flagged
Timothee Brochier - One of the best experts on this subject based on the ideXlab platform.
-
Effect of Small Versus Large Clusters of Fish School on the Yield of a Purse-Seine Small Pelagic Fishery Including a Marine Protected Area
Acta Biotheoretica, 2014Co-Authors: Nguyen Trong Hieu, Pierre Auger, Timothee Brochier, Nguyen-huu Tri, Patrice BrehmerAbstract:We consider a Fishery model with two sites: (1) a marine protected area (MPA) where fishing is prohibited and (2) an area where the fish population is harvested. We assume that fish can migrate from MPA to fishing area at a very fast time scale and fish spatial organisation can change from small to large clusters of school at a fast time scale. The growth of the fish population and the catch are assumed to occur at a slow time scale. The complete model is a system of five ordinary differential equations with three time scales. We take advantage of the time scales using aggregation of variables methods to derive a reduced model governing the total fish density and fishing effort at the slow time scale. We analyze this aggregated model and show that under some conditions, there exists an equilibrium corresponding to a sustainable Fishery. Our results suggest that in small Pelagic fisheries the yield is maximum for a fish population distributed among both small and large clusters of school.
-
climate change scenarios experiments predict a future reduction in small Pelagic fish recruitment in the humboldt current system
Global Change Biology, 2013Co-Authors: Timothee Brochier, Vincent Echevin, Alexis Chaigneau, Katerina Goubanova, Arnaud BertrandAbstract:The Humboldt Current System (HCS) sustains the world′s largest small Pelagic Fishery. While a cooling of this system has been observed during recent decades, there is debate about the potential impacts of rising atmospheric CO 2 concentrations on upwelling dynamics and productivity. Recent studies suggest that under increased atmospheric CO 2 scenarios the oceanic stratification may strongly increase and upwelling-favorable winds may remain nearly constant off Peru and increase off Chile. Here we investigate the impact of such climatic conditions on egg and larval dispersal phases, a key stage of small Pelagic fish reproduction. We used larval retention rate in a predefined nursery area to provide a proxy for the recruitment level. Numerical experiments are based on hydrodynamics downscaled to the HCS from global simulations forced by pre-industrial (PI), 2 × CO 2 and 4 × CO 2 scenarios. A biogeochemical model is applied to the PI and 4 × CO 2 scenarios to define a time-variable nursery area where larval survival is optimum. We test two distinct values of the oxycline depth that limits larval vertical distribution: One corresponding to the present-day situation and the other corresponding to a shallower oxycline potentially produced by climate change. It appeared that larval retention over the continental shelf increases with enhanced stratification due to regional warming. However, this increase in retention is largely compensated for by a decrease of the nursery area and the shoaling of the oxycline. The underlying dynamics are explained by a combination of stratification effects and mesoscale activity changes. Our results therefore show that future climate change may significantly reduce fish capacity in the HCS with strong ecological, economic and social consequences.
Salvador E Lluchcota - One of the best experts on this subject based on the ideXlab platform.
-
distribution and abundance of the pacific sardine sardinops sagax in the gulf of california and their relation with the environment
Progress in Oceanography, 2001Co-Authors: Manuel O Nevarezmartinez, Daniel Lluchbelda, Miguel A Cisnerosmata, Pablo J Santosmolina, Ma De Los Angeles Martinezzavala, Salvador E LluchcotaAbstract:Abstract In 1989–90 the small Pelagic Fishery of the Gulf of California began to show a very marked decline in the catch of its main component, the Pacific sardine (Sardinops sagax). The catch plummeted from 292,000 t in 1988–89 to 7000 t in 1991–92 and 1992–93. This caused a serious economic crisis in the local Fishery fleet and industry, and resulted in the loss of 3000 jobs. In 1993–94 the Fishery showed signs of recovery as the abundance of the Pacific sardine began to recover. The catch improved to 128,000 t in 1993–94 and further to 215,000 t in 1996–97. In trying to understand this great variability, we proposed the hypothesis that the distribution and the abundance of the Pacific sardine of the Gulf of California is determined by the wind patterns (upwelling) and the sea surface temperature. The results of analyzing data from 25 cruises showed the period of low relative abundance between 1990 and 1993 and one of high abundance between 1993 and 1996. The range of the sardine's distribution expanded as its abundance increased and contracted when abundances were low. The relationship between the abundances of the sardine and environmental variables proved to nonlinear and bell-shaped. The adjusted pattern explained 78.8% of the variability of the sardine abundance. The highest abundance are produced by moderate upwelling (13–18 m3s−1 per 10 m of coastline) and sea surface temperatures of between 19°C and 25°C.
Arnaud Bertrand - One of the best experts on this subject based on the ideXlab platform.
-
climate change scenarios experiments predict a future reduction in small Pelagic fish recruitment in the humboldt current system
Global Change Biology, 2013Co-Authors: Timothee Brochier, Vincent Echevin, Alexis Chaigneau, Katerina Goubanova, Arnaud BertrandAbstract:The Humboldt Current System (HCS) sustains the world′s largest small Pelagic Fishery. While a cooling of this system has been observed during recent decades, there is debate about the potential impacts of rising atmospheric CO 2 concentrations on upwelling dynamics and productivity. Recent studies suggest that under increased atmospheric CO 2 scenarios the oceanic stratification may strongly increase and upwelling-favorable winds may remain nearly constant off Peru and increase off Chile. Here we investigate the impact of such climatic conditions on egg and larval dispersal phases, a key stage of small Pelagic fish reproduction. We used larval retention rate in a predefined nursery area to provide a proxy for the recruitment level. Numerical experiments are based on hydrodynamics downscaled to the HCS from global simulations forced by pre-industrial (PI), 2 × CO 2 and 4 × CO 2 scenarios. A biogeochemical model is applied to the PI and 4 × CO 2 scenarios to define a time-variable nursery area where larval survival is optimum. We test two distinct values of the oxycline depth that limits larval vertical distribution: One corresponding to the present-day situation and the other corresponding to a shallower oxycline potentially produced by climate change. It appeared that larval retention over the continental shelf increases with enhanced stratification due to regional warming. However, this increase in retention is largely compensated for by a decrease of the nursery area and the shoaling of the oxycline. The underlying dynamics are explained by a combination of stratification effects and mesoscale activity changes. Our results therefore show that future climate change may significantly reduce fish capacity in the HCS with strong ecological, economic and social consequences.