Impacts of crude oil and dispersants on capelin (Mallotus villosus) reproductive performance

Description

This project will test how interactions between crude oil and oil dispersants affect spawning capelin (their gamete quality and embryo development) in ways that would impair larval recruitment.

Commercially exploited capelin (Mallotus villosus) are the most important fish in the northwest Atlantic food web (and are of significance in the Arctic and Pacific), being major forage for top predators such as Atlantic cod (Gadus morhua), marine mammals, and sea birds. Successful capelin reproduction and recruitment is paramount for the functioning of the marine food web in Atlantic Canada, but their reproductive behaviour puts them at higher risk than any other local fish. During the short reproductive season, capelin form dense schools in nearshore areas and then spawn either in demersal sites (i.e. on the sea floor) or on beaches. From the moment adults aggregate inshore for spawning until larvae drift offshore, capelin would be particularly susceptible to the effects of oil spills that usually concentrate nearshore.

Previous studies have demonstrated the effects of crude oil on sensitive early life stages (i.e. embryos and larvae), however they did not evaluate other critical aspects of recruitment, in particular the potential cumulative crude oil effects on adult exposure just prior to spawning, and gamete performance during the fertilization process. Another potential concern is the use of oil dispersants. While they are considered a reliable response to catastrophic oil spills, it has also been reported that dispersants can interact with oil in a way that releases greater concentrations of toxic components in the water, which has been shown to have higher toxicity than the untreated oil on early life stages of several species.

In this context, investigators will conduct laboratory exposures to assess the effects of various levels of crude oil and dispersants on gonad ripening, sperm quality and performance, embryo survival and larval quality. This will represent the first detailed examination of the potential effects of crude oil and oil dispersant toxicity on fish sperm physiology, and will contribute valuable data to assess ecosystem risks relating to oil transportation in coastal regions.

Program Name

National Contaminants Advisory Group (NCAG)

Year(s)

2016 - 2017

Ecoregion(s)

Atlantic: Gulf of Maine, Scotian Shelf

Principal Investigator(s)

Craig Purchase
Associate Professor, Department of Biology, Memorial University (Newfoundland)

Team Member(s)

José Beirão, Faculty of Biosciences and Aquaculture, University of Nordland, (Norway)