The Genetic Evidence And Otherwise.

• Main Authors: C. T. Taggart, D. E. Ruzzante, D. Cook, I. Kornfield
• Other Authors: The Pennsylvania State University CiteSeerX Archives
• Format: Text
• Language: English
• Subjects: Gadus morhua; Northwest Atlantic
• Online Access: http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.554.1053; http://www.phys.ocean.dal.ca/~taggart/Publications/Taggart_etal_in-VonHerbing_eds_1998.pdf

If the critical assumption of panmixia in exploited cod (Gadus morhua) stocks is invalid at any management level, then management is functionally inconsistent with the principles of resource conservation and the maintenance of biodiversity. With this claim in mind we review some of our studies on the genetic structure of cod populations in the Northwest Atlantic and highlight aspects that may be of value to questions concerning localised cod populations in the Gulf of Maine. We employ microsatellite DNA polymorphism to resolve genetic differences among cod populations (under the null hypothesis of no significant differences between or among populations) as microsatellites are considered the ideal genetic tool for studying closely related groups of animals (high level of co-dominant allelic variation, rapid divergence times, and relative ease of examination). We employ other biological and oceanographic “knowns ” in our assessment of the genetic results. Three case studies illustrate genetic heterogeneity among cod populations: 1) at the small-scale of oceanographic features; 2) at the meso-scale of coastal embayments; and 3) at the large-scale of offshore banks. Our review leads us to one specific hypothesis regarding the existence of at least one localised