Ichthyoplankton of King Harbor, Redondo Beach, CA


Jean Davis

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Ichthyoplankton are fish eggs and larvae which begin their lives as passive drifters, slowly gaining the ability to move independently before recruiting to a reef. Found in local nearsurface waters (above 200 meters) ichthyoplankton are an important source for monitoring trends in population size of adult fishes as well as the overall ecological health of an area. Since 1974 and continuing today, fish assemblages at King Harbor in Redondo Beach are monitored using ichthyoplankton sampling. Samples are collected on a monthly basis using a conical meter net conducting both nighttime benthic tows and daylight surface tows to account for diel vertical migrations (shifts up in the water column for feeding during hours of darkness). Samples are preserved in formalin, volumed, and sorted to remove fish larvae from other zooplankton. Larvae are identified and classified into developmental stages. Mortality curves reveal data on population biomass of adult fish in the area sampled. It has been concluded that King Harbor and its surrounding breakwater acts as a productive artificial reef in contributing to larval populations in the Southern California Bight. Densities of reef fish larvae have been found to be greater in areas adjacent to the reef versus surrounding waters. While it has been confirmed that the harbor serves to support larval reef fish populations, this study is ongoing and will provide a valuable continuum for understanding ecological health of the harbor as a reef system as well as any anthropogenic influences such as local power station intake and output areas.


Dan Pondella




Vantuna Research Group

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