Abstract

Ballona Marsh is a highly modified remnant marsh on the western edge of the Los Angeles Basin bordering Santa Monica Bay. Thirteen stations (collected with small seines) in the marsh are being sampled bimonthly in 1996-1997 to compare with identical monthly collections at the same stations in 1980-81. Seven stations are from the lower marsh (north of Culver Blvd) that is regularly tidal and with relatively high salinities; six stations are in the upper marsh (south of Culver Blvd) which is at higher elevation and usually has lower salinity. Recent samples were taken in October were taken in October, December, and February. The numbers of fishes are comparable with the earlier collections, but fewer stations have fish and the species composition has changed. In 1980-81 the fish numbers and biomass peaked in the spring and fall and were low in the mid-winter and mid-summer. In October and December of 1996 all but one station in the upper marsh were dry. In 1980-81 only the uppermost two or three stations were dry in the summer and fall. Our October, 1996 collections also had relatively large numbers of fish and very few fish were taken in December and February. Native California Killifish, Topsmelt, Arrow Goby, Muduscker, and Staghorn Sculpin are common and mostly in the lower marsh as in 1980-81. Shadow and Cheekspot Gobies, California Halibut, and Diamond Turbot have been rare and found only in the lowest portions of the marsh in both studies. The introduced mosquitofish are common and mostly in the upper marsh. The native Striped Mullet and introduced Yellow-fin Goby were major components of the 1980 study and have yet to be collected in 1996-97. The introduced sailfin molly appeared in the marsh between 1981 and 1986 and is now abundant. Much of the fish fauna is about the same as earlier, but the wetted habitat is reduced, two species (one native and two interested) no longer use the marsh for a nursery, and an additional introduced species has become dominant in much of the marsh.

Camm C. Swift, Department of Biology, Loyola Marymount University, Los Angeles, CA.

Note:Camm Swift made an excellent presentation in June 1999 for the Sierra Club regarding the Steelhead Trout and other fish in the Los Angeles River Watershed. I talked to him at this meeting. As a result of our conversation, Camm Swift mailed a copy of the abstract (reproduced above) to me on 14 June 1999 with a nice note attached that reads: "Roy, Nice to see you at the zoo. Good luck in the Ballona work, Camm."