Fish use of tidal creek habitats in two southern California salt marshes

Fish assemblages from small intertidal creeks (first-order) and from larger subtidal creeks (third- and fourth-order) were sampled seasonally for 1 year at Tijuana Estuary and Sweetwater Marsh in southern California, USA. First-order creeks were dominated by Gillichthys mirabilis, Fundulus parvipinnis, and Clevelandia ios at both sites. At Sweetwater Marsh, species composition and species richness differed between creek orders, as did size structure of F. parvipinnis, one of the most abundant marsh residents; a greater proportion of small juveniles was collected from first-order creeks. At Tijuana Estuary, the larger system, elevations of first-order creeks were higher and fish use of creeks was lower than at Sweetwater Marsh. Shallow habitats are used extensively by several marsh residents, and may provide nursery habitat for juvenile F. parvipinnis. Intertidal creeks should be considered in designs of marsh restoration projects where the creation of habitat for resident ashes is a priority. (C) 2000 Elsevier Science B.V. All rights reserved.