Browsing by Author "Gormley, Ty"

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    Comparing genetic variation among Atlantic cod (Gadus morhua) off Newfoundland and Labrador following the stock collapse
    (University of New Brunswick, 2020) Gormley, Ty; Pavey, Scott
    Following the collapse of the Northern cod stock, there has been much debate regarding the population structure of Canada’s Northern Atlantic cod (Gadus morhua). The objectives of the study are: 1) to determine whether the stock exhibits structure or panmixia and 2) to compare historic cod chromosomal inversion frequency (LG01) to among historic and modern cod. A whole genome scan on 119 historic cod captured between 2001 and 2003 was conducted from four locations spanning the range of the stock and two locations outside the stock. Population structure analysis using 3,907 SNPs suggests that the stock is a single panmictic population. However, additional analyses on only LG01 (15) revealed that historic cod had a higher inversion frequency than modern cod. Taken together, these results provide support for the metapopulation hypothesis and provide novel information on putative adaptive inversion allele changes over a short timeframe.
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    Investigating the genetic structure of Atlantic Cod (Gadus morhua) spawning populations following the collapse of the northern cod stock
    (University of New Brunswick, 2019) Gormley, Ty; Pavey, Scott
    The Atlantic cod (Gadus morhua), within the Northern cod stock, once served as the economic pillar for Newfoundland and Labrador. After years of overfishing and reduced ocean temperature, the stock population collapsed in 1992, driving many to question the genetic structure for its recovery. Currently, the metapopulation and isolation hypotheses have been proposed to describe the genetic structure of the stock, but there is much debate on which is reliable. The stocks genetic structure will be determined using fin clips obtained from 2001- 2003, from various spawning populations, to indicate whether the stock exhibits panmixia. A double-digest restriction site associated DNA technique was used to identify 846 single nucleotide polymorphisms, and the population structure was determined using the Fixation Index (FST). The FST analysis found no significant differences, therefore, spawning populations of the stock are panmictic. Further research is necessary to obtain a more robust genetic structure for extensive ecological management.