Out of the many issues identified and prioritized, there were four which were highlighted for further consideration within the LAPE project.They were selected because they were commonly identified with relatively high priority and they were amenable to further analysis using the ecosystem modelling tools developed. Analyses pertaining to the first two were conducted within the LAPE project.
Issue No. 1: The bait fishery
The large pelagic fisheries of the region are primarily hook and line (longline, trolling, sportfishing) all of which are dependent on bait supplies. The expansion of commercial large pelagic fisheries in the southern part of the region has created an increased demand for bait, with a preference for live bait, if available. Bait species include flyingfish (Hirundichthys sp.), ballahoo (Hemiramphus sp), scads (Decapterus sp) and sprat (Harengula sp.). In the absence of locally caught bait, fishers have either been unable to fish or have purchased imported bait supplies (e.g. frozen squid). This demand for bait has caused price increases for small pelagic fish and created scarcity in the food fish supply of the same species. As a result, there are issues concerning ecological impact of the increased bait fishery, the economic impact of increased small pelagic prices and a potential social issue due to potential loss of a low-price source of protein in rural communities .
What will be the impacts of the required increase in catches of the small pelagic and flyingfish (bait) fisheries to meet the demands of an expanding large pelagic fishery?
Issue No. 2: Trophic linkages between flyingfish and dolphinfish
Although fisheries tend to concentrate on higher trophic level species, there are numerous cases in which two or more commercially important species are linked by either direct trophic linkages or links mediated through other species. In these cases, the impacts of changes in one fishery may affect the catches and/or the biomass of other important commercial species. In the LAPE region there is a note-worthy example in the relation between dolphinfish and flyingfish. Both are already subject to well-developed fisheries. Flyingfish is a particularly important prey of dolphinfish, at least in the southern part of the LAPE. Several other large pelagic groups also prey on flyingfish although none as heavily as dolphinfish. Stakeholder views on the flyingfish fishery were mixed with some still seeing it as a potential expanding fishery while others perceive it as a declining fishery. So, in addition to a scenario for expansion of flyingfish fisheries there is also an interest in estimating if there would be any benefits to a reduction of effort on the flyingfish fishery.
What would be the impacts of increasing effort in the flyingfish fishery on the biomass, catch and value of dolphinfish and other large pelagic species?
What would be the impacts of increasing effort targeting dolphinfish on the biomass, catch and value of the flyingfish fishery? This is complicated by the fact that it would simultaneously remove a predator on flyingfish but increase the demand for flyingfish as bait.
Issue No. 3: Impact of cetaceans in the LAPE area on the fishery
It was noted that most populations of oceanic marine mammals in the region seem to be increasing. This is due to being protected from fishing through most of their ranges and efforts to reduce incidental capture in fishing gear. Cetaceans may impact fisheries by competing with other species in the ecosystem for the same prey, or directly with fisheries for the same target species.
Question: What would be the impact of increasing populations of marine mammals on the resources available for fisheries?
Issue No. 4: Climate change
One prediction is that global warming will result in increased run-off from major rivers and hence increase primary productivity in the region.
Question: What would be the likely impact of increasing primary productivity on the biomass of fish available to fisheries in the region?