Title: Dynamic production model for stock assessment of Norway lobster (Nephrops norwegicus Linnaeus, 1758) in Icelandic waters

Author(s): Vu Trong Dai
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Dynamic production model was used to assess the biomass status of Norway lobsters (Nephrops norvegicus) in southern Icelandic waters. The analyses were based on data collected from the Marine Research Institute, including both biomass indices from surveys and commercial fisheries data. Twenty five age groups and their proportions were estimated by using length frequency distribution and cohort slicing. The growth parameters of nephrops estimated according to von-Bertalanffy equation were: CL∞ = 82.5 (mm), k = 0.1 (yr-1), t0 = 0.1 and ϕ’= 3.87. The relationship between CL and weight was W = 0.55266*L3.14433. The production model shows average estimated biomass of 23,170 (tons) and fishing mortality (Fmean) of 0.33. The maximum sustainable yield of 3,131 tons corresponded to Fmax = 1.071 and optimum sustainable yield of 2,768 tons with F0.1 of 0.357. According to the model, the nephrops stock in southern Iceland is under exploited and higher yield can be obtained by increasing fishing mortality. The spiny lobsters fishery in Vietnam was reviewed and revealed a lack of fishery management system and data. The nephrops fishery management system requiring fishing license, minimum square mesh size of trawl, quota systems based on TAC and closed areas could be applied to the spiny lobsters fishery in Vietnam for the sustainable development of the fishery. Data collection programmes of commercial catches, catch index, and regular surveys including length composition by sex should be developed to assess spiny lobsters biomass status.


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