Fish Hatchery Management - fisheries & aquaculture

TRANSPORTA'I'ION OF LIVL, F'ISHES 351Expanded vermiculiteOakPineCorkStyrofoamFiber glassUrethane1.601.180.740.290.280.250.18"fhe K values indicate that pine must be 4 times as thick as urethane togive the same insulating quality. Generally, combinations of various materialsare used in fabricating distribution tanks.The distribution tank in Figure 109 is constructed with marine plywood,insulated with styrofoam and covered inside and out with fiber glass. Unitsvary in size and may contain several compartments.Warmwater distribution tanks generally are compartmented. Compartmentsfacilitate fish stocking at several different sites on a single trip, permitseparation of species, and act as baffles to prevent water surges. Thenumber of compartments used in tanks ranges from two to eight, four beingmost common. Tanks in current use have 300-700-gallon capacities,averaging about 450 gallons. However, 1,200-gallon tanks occasionally areused to transport catchable size catfish, trout, and bass.Although most tanks presently in use are rectangular, the trend in recentyears has been towards elliptical tanks, such as those used to transportmilk. This shape has several advantages.FIGURE 109. Fiberglass distribution tank with four compartments, each with anelectric aerator (p..o*). Additional oxygen is provided through carbon rods ormicropore tubing on the bottom of the tank. (M.Ne.r.ry National Fish Hatchery,FWS.)