. Commercial fisheries review. Fisheries; Fish trade. 17 Oil Slicks Useful MODULAR BUOY SYSTEM Preliminary tests indicate that oil slicks from large fish schools, such as menhaden, can be detected and used to locate and identify these schools. Fish-oil slicks also have dif- ferent temperatures than the surrounding sea surface. So the presence of fish can be de- tected by monitoring sea-surface tempera- tures. Image Intensifiers The PascagoulaBase has explored another approach to finding and identifying open-sea fish stocks. This uses low-level light sensors, such as image intensifiers, coupled
. Commercial fisheries review. Fisheries; Fish trade. 17 Oil Slicks Useful MODULAR BUOY SYSTEM Preliminary tests indicate that oil slicks from large fish schools, such as menhaden, can be detected and used to locate and identify these schools. Fish-oil slicks also have dif- ferent temperatures than the surrounding sea surface. So the presence of fish can be de- tected by monitoring sea-surface tempera- tures. Image Intensifiers The PascagoulaBase has explored another approach to finding and identifying open-sea fish stocks. This uses low-level light sensors, such as image intensifiers, coupled to closed- circuit TV to detect bioluminescence, or "fire" as fishermen call it, associated with schools of fish. Florida fishermen use "fire" to find Spanish mackerel at night. This "fire" results from movement offish schools, which cause luminescent organisms to glow mo- mentarily. The bodies of rapidly swimming fish are outlined with lights; each leaves a trail of fire as it moves. The image intensifiers amplify surround- ing light 40,000 to 100,000 times. Scientists have been able to observe thread herring schools at night from altitudes of 500 to 5,000 feet. Preliminary tests suggest that low-level light sensors may be used effectively from high altitudes to locate and possibly identify open-sea fish schools over large areas. Value to Commercial Fishermen The Pascagoula research may lead to a system that will sharply reduce the time commercial fishermen spend looking for fish. Such information will permit development of underutilized fishery resources, which now cannot be harvested economically because of search time and other factors. Scientists will have tools to tell them quickly whether fishermen can harvest a resource--and how much they can harvest without depleting it. Scientists at Woods Hole Oceanographic Institution (Mass.) prepare (below) to lower into the ocean a modular buoy system com- posed of glass spheres bolted to a fiberglas
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Keywords: ., book, bookcentury1900, booksubjectfisheries, booksubjectfishtrade
