Analysis of metals in tissues of round gobies (Neogobius melanostomus), sediments, and water at five sites in Erie County, Pennsylvania

Abstract:

The round goby Neogobius melanostomus is a non-native fish that has received much attention in the Great Lakes. Due to its benthic nature, predation on dreissenid mussels, and its role as prey to larger fishes, it likely plays an important role in the transfer of contaminants to higher trophic levels. We used ICP-MS to assess concentrations of Ni, As, Cd, Ba, and Pb in liver, muscle, and otoliths of gobies as well as sediments and water from five sites in Erie County, PA: two open-water sites in Presque Isle Bay (PIB), the shipping channel that connects PIB to Lake Erie, Lake Leboeuf, and Fairview Gravel Pit. Twelve gobies (67-93mm TL), five sediment, and five water samples were collected from each site. Samples were digested following published methodology and analyzed on an Angilent 7900 ICP-MS at Penn State Behrend. One-factor ANOVA revealed differences in concentrations of individual metals in soft tissues, otoliths, sediments, and water among sites. Multivariate analysis revealed differences among sites in metal composition of sediments and water. However, differences in sediment composition did not predict differences in water composition among sites. Multivariate analyses also revealed among-site differences in composition of round goby tissues, both when all tissues were considered together and when tissues were considered separately. Within fish, there was no correlation between composition of liver and muscle or between liver and otoliths, but there was a significant correlation between muscle and otoliths. Differences in sediment composition, but not water composition, predicted differences in all-organ composition of round gobies. Our results suggest that round gobies play an important role in the transfer of metals from sediments (by absorption and/or consumption of benthic prey) to higher trophic levels. Also, care should be taken when selecting tissues for analysis because they do not appear to accumulate or retain metals in the same way.