Fish Ecology Lab
Department of Biology
18111 Nordhoff Street
Northridge, CA 91330-8303
The effects of pollution on growth and fecundity of Paralabrax nebulifer (barred sand bass) in Southern California—Environmental stressors can have detrimental effects on fish populations by limiting the abilities of individuals to acquire resources for growth, reproduction, and survival. Pollutants such as polycyclic aromatic hydrocarbons (PAHs), polychlorinated biphenyls (PCBs), and heavy metals can cause physiological stress in fishes, especially in areas of high pollutant concentrations, like harbors. This study evaluated the impacts of pollutants on growth and fecundity of a common coastal marine fish in Southern California. Paralabrax nebulifier (barred sand bass) is one of the most frequently caught fishes in the multi-million dollar recreational fishery in Southern California. This benthic associated species is a multiple broadcast spawner. In 2009, EPA added barred sand bass to the “limit your consumption guidelines,” due to the accumulation of pollutants. This study was conducted at four sites: two polluted sites within harbors (Los Angeles/ Long beach harbor and San Diego Bay) and two relatively unpolluted sites located outside of harbors (San Clemente reefs and Huntington flats). Fish were collected using hook and line and pole-spear via SCUBA from February to September 2010. Standard length and mass were recorded to determine growth and condition (weight-at-age and weight-at-length relationship). Liver and tissue samples were frozen and stored to determine pollutant loads. Gonads were weighed and stored to determine reproductive potential by three methods: gonadosomatic index, mature egg and hydrated egg method.
Measures of growth and condition (weight-at-age and weight-at-length) did not differ between the polluted and unpolluted sites, implying that concentrations of pollutants in the harbors studied were not high enough to affect growth rates. Hepatosomatic index did not differ between the polluted and unpolluted sites, suggesting that the level of pollutants is not high enough to induce a response. Reproductive potential did not differ between the polluted and unpolluted sites. My work to date implies that these pollutants have little effect on barred sand bass based on these physiological parameters. Thus, future work will measure tissue concentrations of pollutants in the fish sampled to further explore the possibility of sub-lethal effects of pollution and to evaluate the extent to which pollutants are accumulated in the tissues of this species in different habitats.