Reproductive investment in Atlantic cod populations off Newfoundland: Contrasting trends between males and females

Type Article
Date 2017-08
Language English
Author(s) Baulier LoicORCID1, 2, 6, Morgan M. Joanne3, Lilly George R.3, Dieckmann Ulf4, Heino Mikko1, 2, 4, 5
Affiliation(s) 1 : Inst Marine Res, N-5817 Bergen, Norway.
2 : Univ Bergen, Dept Biol, N-5020 Bergen, Norway.
3 : Fisheries & Oceans Canada, Northwest Atlantic Fisheries Ctr, St John, NF AIC 5X1, Canada.
4 : Int Inst Appl Syst Anal, Evolut & Ecol Program, A-2361 Laxenburg, Austria.
5 : Natl Taiwan Univ, Inst Oceanog, Taipei 106, Taiwan.
6 : IFREMER, Fisheries Biodivers Unit, UMSR LEEISA, BP 477, F-97331 Cayenne, France.
Source Facets (2371-1671) (Canadian Science Publishing, Nrc Research Press), 2017-08 , Vol. 2 , P. 660-681
DOI 10.1139/facets-2017-0005
WOS© Times Cited 3
Keyword(s) reproductive investment, fisheries-induced evolution, Atlantic cod, gonad weight

Life history theory predicts selection for higher reproductive investment in response to increased mortality among mature individuals. We tested this prediction over the period from 1978 to 2013 for three populations of Atlantic cod (Gadus morhua) off Newfoundland. These populations were heavily fished for a long period. We considered changes in standardized gonad weight as a proxy for changes in gonadal investment. We accounted for the allometry between gonad and body weight, individual body condition, water temperature, and potential spatial and density-dependent effects. Males display significant temporal trends in gonadal investment in all populations; in agreement with theoretical predictions, these trends show increased gonadal investments during the earlier part of the time series when mortality was high, with the trends leveling off or reversing after the later imposition of fishing moratoria. In contrast, females display patterns that are less consistent and expected; significant trends are detected only when accounting for density-dependent effects, with females in two populations unexpectedly showing a long-term decline in gonadal investment. Our results support the hypothesis that fisheries-induced evolution has occurred in gonadal investment in males, but not in females, and suggest that gonadal investment is more important for male reproductive success than expected in this lekking species.

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