The study committee met to discuss the current status and next steps of the project. They reviewed the top priority research questions generated through the stakeholder consultation process, and will use these to guide the outputs generated from the project to ensure the outputs address the most urgent stakeholder needs.
Updates on the progress in each phase:
Phase I: with inputs from many agencies we have compiled the most extensive high resolution picture of trawling activity on the world’s continental shelves. We are continuing to seek more data to develop this picture, with a particular focus on Africa, Asia and South America. For the same areas we are compiling information on seabed habitats to link the footprint of trawling to the distribution of habitat. These layers will underpin the Phase 3 analysis on the interactions between trawling and the environment, where we assess the positive and negative consequences of existing practices. The map above shows where we now have data sets (yellow pins) and where we have inquiries that we hope will lead to further data sets (black pins).
Phase II will compile and evaluate the impact of mobile bottom fishing on the abundance and diversity of biota, looking especially at the key factors of intensity of trawling, gear type and type of habitat trawled. Given the great interest in the subject and criticisms of previous reviews (Collie et al. 2000; Kaiser et al. 2006) that there was bias in the choice of studies included, the committee felt that a very thorough and transparent process be used to identify studies for the data synthesis. Thus the internationally recognized “systematic review” has been applied using the collaboration for environmental evidence (CEE) guidelines, although it is a time consuming process. The approach of using systematic reviews in ecology and conservation is a relatively recent development and has its roots in the medical sciences. It is considered the most robust approach to reviewing the literature from which meta-data are compiled. It implicitly eliminates the risk of bias and is a transparent and repeatable methodology. The systematic review protocol has been reviewed by all of the trawl committee members as well as stakeholders involved in the project and is now ready to be submitted for peer review in the open access journal “Environmental Evidence”.
Current aims include completion of searches by the end of January 2014 and the completion of all data extraction for the meta-analysis by the end of April 2014.
Phase III will conduct a risk analysis of the impacts of trawling on alternative habitats, regions and fisheries. Roland Pitcher presented a worked example for a single Australian trawl fishery. Because this example used confidential data we are not able to share it in the meeting report but Roland has prepared a mock example given as Appendix II in this report that does not use any confidential data.
Phase IV will look at the medium-term and long-term impact of trawling on the productivity and sustainable yield of different target species relative to the effect of fishing. After a preliminary literature review presented during the meeting it was showed that the existing studies are fragmentary and thus a meta-analysis is not possible. Therefore, a structured review of empirical and modeling studies will be carried out around three axes that were identified as the main ways in which trawling can affect the productivity of the target species: (i) Trawling impacts on the habitat of the target species (ii) Trawling impacts on the predators of target species (iii) Trawling impacts on the prey of target species. The structured review will lead to a summary of current knowledge and recommendations about a research agenda that is required to address question on the trawling impact on fish productivity. The work plan has been discussed and specific tasks have been allocated. A 1st draft of the review paper will be available at the next meeting (September 2014).