Wcpo Ecosystem Indicator Trends and Results from Ecopath

Introduction This Information Paper contributes to Project 46 " Development/review of models, such as full development of an ECOSIM model, for evaluation of fishery and environmental impacts on ecosystem, including development of reference points " and provides complimentary analyses for Project 43 " Ecological Risk Analysis, including PSA " and Project 62 " SEAPODYM simulation modeling ". The responsibilities for RFMOs has expanded over the last decade with monitoring and reporting upon the ecosystem impacts of fishing now an important aspect of evaluating the sustainability of fisheries. A critical step to developing appropriate monitoring and reporting protocols is an understanding of the processes by which marine ecosystems are structured. Fishing is not the only anthropogenic factor that may have negative impacts on marine ecosystems and decoupling fishing from these other impacts (e.g. climate change) will aid in the identification of appropriate ecosystem indicators of fishing impacts and appropriate reference points for implementation of management actions. Ecosystem modeling in combination with analyses of fisheries catch and observer data is one of the tools that can assist this process. In addition to assisting with the identification of ecosystem indicators ecosystem models can also be used to assess whether management is robust to the combined impacts on oceans. To progress the identification of appropriate ecosystem indicators for the WCPO this paper reports on: (1) recent comparative analyses of logsheet and observer data in Hawaii and New Caledonia to examine trends in bycatch catch rates and ecosystem indicators (mean trophic level of the catch, annual proportion of apex predators and annual proportion of predator with high turnover); (2) recent progress on modeling the warm pool ecosystem, with simulations of the impact of fishing and climate change undertaken. The Scientific Committee is invited to both note the report, but also provide guidance on the utility of this report as an regular product to complement information provided in the Ecosystem and Bycatch Theme and the general working papers that summarizes the WCPO fisheries. Results Logsheet and Observer Data Statistically significant linear trends were detected for 9 species in Hawaii: declining trends for albacore, bigeye, blue shark, shortbill spearfish and striped marlin, and increasing trends for dolphinfish, sickle pomfret, escolar and snake mackerel and no significant trends for skipjack, yellowfin, wahoo and lancetfish. Changes were between 3% and 9% annually for species with decreasing trends, and were from 6% to 18% annually for species with increasing trends. …