Using indicators for evaluating, comparing and communicating the ecological status of exploited marine ecosystems. Part 1: the IndiSeas Project
|The IndiSeas Working Group has developed a suite of indicators, designed to provide insight into the effects of fishing on exploited ecosystems. Using data from 19 ecosystems, across 32 countries, a list of candidate indicators were proposed and evaluated on the basis of four criteria: ecological significance, sensitivity, measurability and public awareness. The first two of these were taken as basic requirements that had to be fulfilled if an indicator was to be included in the final set, i.e. the indicator must rely on strong theoretical knowledge of the effects of fishing on communities (ecological significance) and must be sensitive to changes due to fishing. The third, measurability, was crucial, as the ecosystems are spread across a range of socio-economic regimes and sampling strategies. Therefore, an indicator must be easily and inexpensively estimated, from either direct observations or model output. Use of the final criterion, public awareness, reflected the idea that any indicator must be accessible to all stakeholders in an ecosystem, not just scientific experts. As a result, statistics such as the slope of the size spectrum were excluded.||
As well as the selection criteria, each indicator was linked to one of four possible management objectives with which it was most closely associated: conservation of biodiversity, maintenance of ecosystem stability, maintenance of ecosystem structure & function, and maintenance of resource potential. This was done to aid in prioritising management strategies. Finally, each of the indicators was assessed as to its comparability across ecosystems (i.e. could it be used to identify ecosystem state), and its ability to identify changes over time (trends).
The final set of indicators proposed are as follows: mean length of fish, trophic level of landings, proportion of under- and moderately-exploited stocks, proportion of predatory fish, mean lifespan, 1/coefficient of variability (i.e. biomass stability), total biomass, and biomass/landings. These were then calculated for each of the 19 ecosystems using fisheries-independent survey data, catch data, or ecosystem model data. Expert knowledge on each of the ecosystems was also sought in order to contextualise the results and identify the effects of fishing separate from other potential drivers. The working group then developed a 'dashboard' of pie diagrams and bar plots to represent the calculated indicators in a comparable and easily understood fashion. This will hopefully lead to dissemination of the research beyond purely scientific circles, and to engagement of the local community in active management of the resource.
Summary for MEECE Research Highlights by Rob Holmes
Shin Y.-J., Shannon L.J., (2010). Using indicators for evaluating, comparing and communicating the ecological status of exploited marine ecosystems. Part 1: the IndiSeas Project. ICES Journal of Marine Science, 67: 000-000.