Managing fishing gear to encourage ecosystem-based management of coral reefs fisheries

Abstract

We present fisheries landing data from two tropical countries, Papua New Guinea (PNG) and Kenya, and show that each gear type causes a unique and consistent partitioning of the species and functional groups it targets. Partitioning by gear can be used to influence ecological processes and biodiversity on coral reefs and to respond to disturbances such as coral bleaching. Hook and line capture a higher proportion of top carnivores and piscivores and target species with low susceptibility to coral bleaching. Traps, drag nets, and spearguns capture mostly herbivores and omnivores and target the highest proportion and number of fish species that are moderately susceptible to the effects of coral bleaching. We argue that the use of specific gears can be actively managed to encourage the recovery of select functional groups and adaptively manage for reducing high erect algae cover and sea urchin dominance, increasing coral cover, and reducing detrimental effects of coral bleaching. We present a simulation and conceptual model that describes the effects of gear and effort on fisheries yields and suggest a mechanism for practically implementing this model. Spearguns are predicted to have the highest diversity and yields of catch, but can also result in decline in herbivorous fishes, which has serious consequences for recovery and resilience of the ecosystem. Further understanding of fishing gear effects on specific fish functional groups at a broader selection of reef locations will be valuable in developing adaptive gear-based management in a changing climate.