Biology of the Roughhead Grenadier (Macrourus berglax) in the Eastern Canadian Arctic
Standing
Undergraduate
Type of Proposal
Oral Presentation
Faculty
Faculty of Science
Faculty Sponsor
Nigel E. Hussey
Proposal
The roughhead grenadier, Macrourus berglax, is a common by-catch species of Canadian Greenland halibut fisheries in the North Atlantic. Information about this species is limited, particularly at its most northern distribution, but it is suggested that their K-selected life history traits (slow growth rate, late age at sexual maturity and low annual fecundity) make them vulnerable to overfishing. Given it is listed as “special concern” by COSEWIC, it is imperative that a better understanding of the species, and their role in surrounding ecosystems, is developed. To update and expand the knowledge of this species, this project examined size based diet and condition index profiles of two groups of roughhead grenadier, sampled from both a northern (Baffin Bay) and southern (Davis Strait) fishing site. By using gonado- and hepatosomatic indices, stomach content analysis, and stable isotopes (δ15N and δ13C of muscle and liver tissue) we can draw conclusions on fitness, energy storage, diet and trophic ecology. Following preliminary observations, it is expected that there will be a difference in both the gonado- and hepatosomatic indices across the two sampling sites due to different stages of reproduction. In addition, it is predicted that, due to latitudinal differences between the sample locations, the northern group will exhibit a more restricted diet due to lower available prey species at higher latitudes. Concurrently, because stable isotope values are influenced heavily by diet (δ15N) and location of foraging (δ13C), it is predicted that grenadier body size, prey diversity, and δ15N will be positively correlated in both Baffin Bay and the Davis Strait, whereas δ13C will differ between the sample sites. The results from this study will aid in creating an ecological baseline for the roughhead grenadier, assist the development of ecosystem management approaches, and enhance our ability to assess the vulnerability of this understudied species.
Grand Challenges
Sustainable Industry
Biology of the Roughhead Grenadier (Macrourus berglax) in the Eastern Canadian Arctic
The roughhead grenadier, Macrourus berglax, is a common by-catch species of Canadian Greenland halibut fisheries in the North Atlantic. Information about this species is limited, particularly at its most northern distribution, but it is suggested that their K-selected life history traits (slow growth rate, late age at sexual maturity and low annual fecundity) make them vulnerable to overfishing. Given it is listed as “special concern” by COSEWIC, it is imperative that a better understanding of the species, and their role in surrounding ecosystems, is developed. To update and expand the knowledge of this species, this project examined size based diet and condition index profiles of two groups of roughhead grenadier, sampled from both a northern (Baffin Bay) and southern (Davis Strait) fishing site. By using gonado- and hepatosomatic indices, stomach content analysis, and stable isotopes (δ15N and δ13C of muscle and liver tissue) we can draw conclusions on fitness, energy storage, diet and trophic ecology. Following preliminary observations, it is expected that there will be a difference in both the gonado- and hepatosomatic indices across the two sampling sites due to different stages of reproduction. In addition, it is predicted that, due to latitudinal differences between the sample locations, the northern group will exhibit a more restricted diet due to lower available prey species at higher latitudes. Concurrently, because stable isotope values are influenced heavily by diet (δ15N) and location of foraging (δ13C), it is predicted that grenadier body size, prey diversity, and δ15N will be positively correlated in both Baffin Bay and the Davis Strait, whereas δ13C will differ between the sample sites. The results from this study will aid in creating an ecological baseline for the roughhead grenadier, assist the development of ecosystem management approaches, and enhance our ability to assess the vulnerability of this understudied species.