Larval exposure to shared oceanography does not cause spatially correlated recruitment in kelp forest fishes

Abstract

In organisms that have a life history phase whose dispersal is influenced by abiotic forcing, if individuals of different species are simultaneously exposed to the same forcing, spatially correlated settlement patterns may result. Such correlated recruitment patterns may affect population and community dynamics. The extent to which settlement or recruitment is spatially correlated among species, however, is not well known. We evaluated this phenomenon among 8 common kelp forest fishes at 8 large reefs spread over 30 km of the coast of Santa Catalina Island, California. In addition to testing for correlated recruitment, we also evaluated the influences of predation and habitat quality on spatial patterns of recruitment. Fish and habitat attributes were surveyed along transects 7 times during 2008. Using these repeated surveys, we also estimated the mortality rate of the prey species that settled most consistently (Oxyjulis californica) and evaluated if mortality was related to recruit density, predator density, or habitat attributes. Spatial patterns of recruitment of the 8 study species were seldom correlated. Recruitment of all species was related to one or more attributes of the habitat, with giant kelp abundance being the most widespread predictor of recruitment. Mortality of O. californica recruits was density-dependent and declined with increasing canopy cover of giant kelp, but was unrelated to predator density. Our results indicate that physical forcing of larval delivery did not generate spatially correlated patterns of recruitment in a suite of temperate-reef fishes. Copyright © Inter-Research 2013.