The Effect of Seafood Processing Plant Effl uent on Sentinel Fish Spe- cies in Coastal Waters of the Southern Gulf of St. Lawrence, New

This study evaluated effects of effl uents discharged by seafood processing plants on populations of fi sh living in shallow estua-rine waters of the southern Gulf of St. Lawrence. To monitor potential nutrient and/or toxicity impacts on fi sh populations living and possibly feeding in the effl uent, we measured indices of survival (age), growth (weight-at-age), reproduction (gonad weight), and energy storage (liver weight, condition factor) on mummichog (Fundulus heteroclitus) and Atlantic silverside (Menidia menidia) in spring, summer, and fall. Fish exposed to effl uents in three bays were compared to fi sh from a local reference site within the same bay and from regional reference sites in bays without seafood plants. Mummichog caught near seafood processing plants showed a number of differences from reference fi sh consistent with a localized nutrient enrichment effect including elevated growth (3 of 3 plants), liver size (2 of 3), and condition factor (1 of 3) in at least one of the months sampled. Female silverside caught near one of the three fi sh plants showed an elevated condition factor in spring, but other-wise silverside did not differ signifi cantly from all four reference sites. In a number of cases, fi sh exposed to effl uent differed from reference fi sh sampled from bays without fi sh plants but not from the local reference site, implying that the entire bay was affected either by the seafood processing plant or by some other factors. No harmful impacts such as reduced growth or survival were found in our study, possibly because the processing plants studied were relatively small and the amounts of waste discharged could be fl ushed by tides and currents and/or assimilated by the fi sh and other biota in the receiving environments