Current usage of fisheries indicators and reference points, and their potential application to management of fisheries for marine invertebrates

The use of indicators in management of invertebrate resources is placed in the context provided by more extensive applications in finfish fisheries. Indicators proposed for the Convention on International Trade in Endangered Species based on extent-of-decline and trend analysis are appropriate should full assessments be unavailable. Measuring reproductive performance frequently builds on egg-per-recruit considerations, given that age structure and stock-recruit relationships are rarely available. Reference points derived from models are compared with direct use of data series, and a broad-brush approach providing a redundancy of indicators is recommended. Indicators may measure productivity as well as biomass and exploitation rate, but ecosystem, spatial, habitat, environmental characteristics, and socio economic considerations also require monitoring. There is a need to integrate multiple indicators and limit reference points into harvest rules and other decisional infrastructures. The various driving force - pressure - state - impact - response classifications of indicators in use for environmental assessment are now being proposed for marine resources and offer one context for combining multiple indicators. Another is provided by the traffic light approach already used for invertebrate fisheries. The use of indicators and reference points in stock rebuilding is described.