| 英文摘要 |
Jumbo (or Humboldt) squid (Dosidicus gigas) is a large pelagic ommastrephid squid inhabiting in the waters of East Pacific Tropical. The commercial fishery on this species has increased since late 1990s. The temporal and spatial variations of abundance, pertaining mechanism and the fishing impacts on squid and the marine ecosystems they involved are of major interests to researches. The short-lived characters of cephalopod populations make them reponse quickly to the change of environmental conditions. Thus, establishing the relationship between abundance variation of squid and environmental variables have been used as an alternative option while analysing the variability of squid stocks. However, environmental factors cannot be controlled or well-predicted by empirical models. The traditional models of stock assessment not only provide the basic scientific information on stock status, but also can be applied to the practical actions for fisheries management. The purposes of this projects are: (1) to explore the spatial distribution pattern of jumbo squid; (2) to analyze the CPUE variations and effects of environmental variables by GAM; (3) to estimate the population size and proportional escapement by depletion method ;(4) to maintain the database of catch and effort data of jumbo squid fishery. The working items are, 1) Re-arrange the dataset of jumbo squid in a monthly basis with a spatial resolution of 0.5 degrees. 2) Explore the spatial distribution patterns by GIS tools. 3) Analyze the CPUE variation by GAM with temporal, spatial and environmental variables. 4) Estimate initial population size and catchability coefficient by depletion methods. 5) Maintain and update fisheries data in 2010. The expected results are, 1) Understand the spatial distribution patterns of squid stocks. 2) Understand the CPUE trend and potential effects of environmental variables. 3) Understand the stock status and the exploitation rate. 4) Establish the empirical models for variations of jumbo squid stocks. |