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Environmental impact studies and bio- logical research programs often require a determination of the nwnber and distribu- tion of fish at various life stages and habitats. Conventional daily or weekly 19 The continuous fish egg and larvae sam- pler pumps water through a sloped screen that concentrates the samples. A diverter then separates and preserves the samples over a specific period of time or volume. Patent Granted for New Continuous Fish Egg and Larvae Collection System STEVEN HIEBERT and DANNY KING Applied Sciences Branch sampling practices, which require the col- lection of small aquatic animals orlarvae, have at times failed to provide reliable data. To address this problem, Steven Hie- bert, Biologist in the Environmental Sciences Section, Applied Sciences Branch, developed a Continuous Fish Egg and Larvae Collection System. Steven recently received U.S. Patent No.5, 181,479 for this invention. This system continuously collects and preserves fish eggs and larvae (along with small aquatic animals and biota) by filtra- tion of known volumes of water, and provides quantifiable data for studies related to water diversions and entrain- ment of fish eggs and larvae in the Sacramento/San Joaquin Delta area, California. An inline flowmeter records the sample volume, and the number of samples is lim- ited only by the number of collection buckets set up under the sampler diverter or by the frequency of sampler collection bucket unloading. The system can be set up on a floating pontoon deck or mounted at the water's edge where the samples can be pumped to the device. This collection system is valuable in fishery studies where egg and larval den- sity, survival, development, and timing and/or duration of fish reproduction must be determined. The continuous sampler can provide reliable indices of seasonal and diel densities of eggs and larvae with careful site location, system verification, and determinations of the organism retrieval efficiencies from pumped sam- ples. In addition, continuous egg and larval data taken upstream from water diversions can minimize egg and larvae entrainment by providing an early warning for poten- tially altering diversion patterns.