Conservation Genetics 2: 257–269, 2001. © 2001 Kluwer Academic Publishers. Printed in the Netherlands. 257 Stability in the historical pattern of genetic structure of Newfoundland

• Main Authors: Daniel E. Ruzzante, Christopher T. Taggart, Roger W. Doyle, Doug Cook
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Published: 2001
• Subjects: Newfoundland; Gadus morhua
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.458.2382; http://myweb.dal.ca/ruzzante/pubs/ruzzante et al cod historical.pdf

otoliths, population structure, spawning fidelity We report on evidence of long term stability in the geographic pattern of genetic differentiation among cod (Gadus morhua) collected from 5 spawning banks off Newfoundland and Labrador over a period spanning three decades (1964–1994) and 2 orders of magnitude of population size variation. Six microsatellite DNA loci amplified from archived otoliths (1964 and 1978) and contemporary (1990s) tissue samples revealed fidelity to natal spawning banks over this period. A two level (spawning bank and decade) hierarchical and multilocus AMOVA indicated that 1.55 % of the total variation in allele frequencies could be attributed (P = 0.036) to spatial structure while no variance component could be attributed to temporal changes. A finer scale analysis among cod from just 3 of these spawning banks reveals, however, evidence consistent with some post-collapse mixing between cod from two banks. In the context of fisheries management and conservation, the survival of the spatial pattern of genetic differentiation during the population collapse suggests that if recovery eventually occurs it will likely be through population re-growth in situ rather than by migratory influx.