| Article ID | Journal | Published Year | Pages | File Type |
|---|---|---|---|---|
| 4543189 | Fisheries Research | 2013 | 6 Pages |
Locally-adapted subpopulations of Atlantic cod are found in both the northwest and northeast Atlantic and exhibit differences in morphology, behavior and physiological characteristics. We conducted experiments to determine if demonstrable differences were evident in egg buoyancy and antifreeze glycoprotein production between captive populations of genetically divergent winter and spring-spawning cod from the Gulf of Maine. Fertilized eggs (<24 h post-spawning) were collected from both populations on 3 dates and transferred to 3 controlled-temperature rooms (5, 10, and 12 °C). Egg buoyancy was determined in triplicate samples, at each temperature, in seawater ranging from 28 to 35 ppt with 0.5 ppt increments. No significant differences in mean neutral buoyancy (∼1.024 g/mL) were found between stocks or treatment temperatures. Antifreeze glycoprotein (AFGP) production was examined in captive-bred cod juveniles (13–24 cm) from both populations held at 0 °C for periods ranging from 20 to 35 days. AFGP were first produced on day 30, although no differences were found in AFGP production in either population. Our results do not support the hypothesis that physiological differences in egg buoyancy and anti-freeze protein product exist between these two cod populations. The similarity in expression of these traits may reflect the high level of nutrition that both broodstock populations received, and the common juvenile size during cold-water exposure.
► Egg buoyancy was determined for spring and winter-spawning Atlantic cod from the Gulf of Maine from fertilization through hatching. ► Antifreeze glycoproteins were induced in juvenile cod from spring and winter-spawning stocks by holding them at 0 °C for periods of 20–35 days. ► Antifreeze glycoproteins were induced after 30 and 35 days but not at 20 and 25 days. No differences in egg buoyancy were found between stocks or through development.
