Hawaii FEP - Western Pacific Fishery Council

toward larger size fish and larger sizes of a given species (Dalzell 1996). Catch composition mayalso be different between day and night when different groups of fish are active or sedentary.Night divers can take advantage of the sleeping habits of some parrotfish to cluster in“dormitories” on the reef and, therefore, be especially vulnerable to spearing.Hawaiian spearfish catches are dominated by parrotfish, surgeonfish, octopus, and squirrelfish.Other common families—such as emperors, snappers, and jacks—also contribute to catches.Fish TrapsFish trapping for finfish is not widely practiced in the Western Pacific region; however it isconducted in Hawaii. Traps, like nets, take a large random assortment of different species thatprobably reflects the proportions of different species groups on coral reefs. Surgeonfish dominatecatches in Hawaii, making up 31 percent of commercial landings, and are comparable to reef fishcatches in traps elsewhere in the Pacific (Dalzell 1996).The main commercial trap fishery on Hawaii’s coral reefs occurred in the NWHI targeting spinylobster and slipper lobster, rather than reef fish. This fishery is now effectively closed. However,there is some harvest of reef fishes using fish traps. Selection effects in traps are a function of thesoak time, mesh size, materials used to construct the traps, trap design, and the depth andposition of the set. Traps set in relatively shallow water with little or no bait will generallymaximize catches within 4–5 days. Traps baited with fish such as aku (skipjack tuna) or sardinesand set on deep reef slopes may catch sizeable quantities of fish in a matter of hours rather thandays, but the composition is very different, reflecting the generally large highly mobile carnivorecomplex of the deep reef slope. Lost traps may become a problem through ghost fishing,although eventually ingress and egress from the traps reaches equilibrium. As with the lobstertraps, seawater-degradable pins or panels can be built into traps so that they lose their ability tohold fish.NetsIn Hawaii, gillnets are used to catch a variety of species including surgeonfish, snappers,goatfish, and rudderfish (DeMello 2004). Gillnets are also often used to target bigeye scad orakule. For smooth fusiform—or cigar-shaped—fish, gillnets tend to select a normally distributedsize range, with the lower and upper size limits dependent on mesh size. Spiny fishes may bevery vulnerable to gillnet catches, regardless of mesh size, because of tangling. Seasonality canalso influence gillnet catches. Fish become more vulnerable during spawning season becausegonad development increases their girth and spawning changes behavior (Ehrhardt and Die1988). The selection effects of gillnets are further complicated by the type of material used, thehanging ratio or measure of meshes per unit of length, the way the net is deployed on a reef, thetime of day set, and length of soak. If gillnets are not checked regularly, bycatch may increase.Entangled fish build up in the net; if they are not removed, they are either preyed on or rot andbecome unsaleable. Gillnets are primarily used in State waters in Hawaii, where their use isincreasingly being regulated. Currently gillnets must generally have a minimum stretched meshsize of two inches. They must be checked at least once every two hours and cannot be left inplace for more than four hours in any 24 hour period.125