O'Donnell, Pajaro & Vincent (2010) provide an interesting contribution to the study of indigenous/traditional knowledge and its modern relevance to marine conservation in insular south-east Asia, particularly given the rapid pace of socioeconomic change and ecological degradation in the region. The article examines how accurately fishermen in the Philippines report declines of the seahorse Hippocampus comes over a period of several decades by comparing fishermen's interviews of past and current declines with daily fishermen logbook data. Given the dissonance between the results of these two datasets (due to retrospective bias), the authors conclude that caution should be exercised when fishermen's knowledge regarding the status of a fishery are incorporated into quantitative conservation assessments.
The conclusions of this particular case study are reasonable and important to consider when reconstructing historical trends in small-scale data-less artisanal fisheries. I would suggest, however, that researchers also need to consider ethnoecological knowledge in the context of a peoples' holistic understanding of the local environment, rather than on peoples' understanding of single-species trends only, which may suffer from retrospective bias as suggested by this paper. For fishers, an in-depth and holistic assessment of the local ecosystem affords an adequate cognitive framework to exploit its productive potential. Therefore, a complete analysis of human use of a particular marine environment depends on the study of its ecological structure and processes, as well as on the appraisal of its human ecology more generally. Consequently, researchers need to analyze the productive practices exerted by local inhabitants on the marine environment including an analysis of spatio-temporal human resource exploitation patterns (e.g. seasonal changes in fishing gear), human responses to variability in inter- and intra-habitat relative productivity and the influence of this variability on subsistence and economic fishing strategies, and human threats to particular marine habitats. In sum, only a holistic approach to the biological and social nature of a people's cognition and use of a given seascape will allows us to design managerial schemes that are more comprehensive. This, in turn, will enhance local participation in the management and conservation of single and/or multiple tropical inshore species.