FINE-SCALE DISTRIBUTIONS OF PLANKTONIC FISH EGGS IN THE VICINITIES OF BIG SYCAMORE CANYON AND VANDENBERG ECOLOGICAL RESERVES, AND ANACAPA AND SAN MIGUEL ISLANDS, CALIFORNIA

Nearshore ichthyoplankton surveys were conducted during late winter and early summer 1998, at four sites in southern California: Big Sycamore Canyon and Vandenberg Ecological Reserves, and Anacapa and San Miguel Islands. A continuous underway fish egg sampler (CUFES) was used to sample along each of three or four transect lines oriented alongshore and spaced at about 0.8 kni or 1.6 km intervals offshore, and a bongo net was towed vertically through the water column at a series of stations spaced about 0.8 km or 1.6 km apart on each line. A total of 41 fish egg taxa and an unidentified fish egg category were collected: 30 taxa in winter and 29 in summer. Winter fish egg collections were dominated by northern anchovy; California halibut, speckled sanddab, white croaker, and Pacific hake eggs also were common. Summer egg catches were more evenly distributed over several taxa, primarily senorita, California sheephead, California barracuda plus white seabass, and speckled sanddab, as well as unidentified eggs. Collections of eggs in early developmental stages suggested that many taxa spawned at night. Senorita spawned during the day, California sheephead probably spawned primarily during the day, and California halibut may have begun spawning during the afternoon and continued into the evening. Both frequency of occurrence and abundance of eggs tended to be higher inshore and were much reduced on the most seaward line for the more common shorefish taxa. White croaker and California sheephead probably spawned primarily shoreward of about the 30 m isobath, and speckled sanddab and senorita shoreward of about the 60 m isobath. California halibut apparently spawned primarily between about the 40 and 60 m isobaths, and California barracuda and white seabass spawned over a broader depth range, about 45-90 m. Abundances of California halibut and white croaker eggs were highest at the Big Sycamore Canyon site, while the islands, especially Anacapa Island, were important sites for Cahfornia sheephead, senorita, California barracuda, and white seabass spawning. The CUFES proved to be an effective sampler for fine-scale distributions of planktonic fish eggs, but may inadequately sample taxa or developmental stages whose vertical distributions are centered above or below its intake depth. Use of another sampler that covers the entire vertical range of the taxa of interest is a necessary adjunct to CUFES sampling.