Reef finfishing pressure risk model for Pacific Island countries and territories

Abstract

A reef finfishing pressure risk assessment model was developed to predict the status of reef and lagoon fisheries in terms of the current likelihood for sustainable or unsustainable finfishing for any given rural coastal community and its associated reef area in the Pacific Island countries and territories (PICTs). The prediction model aimed at developing a robust system that allows planners to confidently classify any coastal rural site within PICTs with a minimum and relatively easy-to-obtain dataset as being exposed to four classes of low to high finfishing pressure. This model is a response to limitations on data regarding current resource and user status in PICTs that make it difficult to ascertain fish supply for food security and livelihood of coastal communities. The model is based on the latest reef productivity scenarios developed based on a global review of currently known landing data and ecological footprints, reported likelihood of reduced reef productivity in PICTs due to ecological and human factors, and the use of current finfish catch rates collected as a proxy for fishing pressure. The prediction model was developed on the basis of a regional dataset including 63 study sites in 17 PICTs using linear discriminant analysis. The smallest feasible model with a leave-one-out error rate of 14.3% demands nine input variables that can be easily obtained and require only a minimum survey effort. Statistically significant response of decreasing fish length in six fish families important to artisanal fisheries in PICTs (Acanthuridae, Lethrinidae, Mullidae, Scaridae, Serranidae and Siganidae) to increasing catch rates or increasing fishing pressure proxies was used as an independent external factor to validate our hypothesis and the model developed. The reported catch length for Acanthuridae, Scaridae and Serranidae was statistically significantly different between the four finfishing pressure risk groups defined. Due to the lack of data on the natural status and productivity of the coral reefs in question and their historic use, care should be taken in interpretation of current catch rate figures. Classification of sites at low current finfishing pressure risk may reflect catch rates that are adapted to low stocks, either caused by previous depletion or due to natural unfavorable conditions. At the same time, sites classified as being at potentially high finfishing pressure risk may indeed be subject to current overfishing, but may as well feature high natural stock and productivity assets that allow for higher catch rates than elsewhere.