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Antifreeze proteins: their role in cod survival and distribution from egg to adult

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posted on 2025-01-29, 14:12 authored by Sally V. Goddard, Garth L. Fletcher

“Northern” Atlantic cod (Gadus morhua L.) inhabiting the ocean adjacent to Newfoundland/Labrador (NAFO Divisions 2J and 3KL) face one of the harshest thermal regimes of the cod’s distributional range. Winter water temperatures between — 1.0°C and —1.8°C (the freezing point of sea water) are frequently observed. The equilibrium freezing point of the unprotected plasma of most marine teleosts (cod included) is approximately —0.7°C. Since plasma freezing points (p.f.p.) approximate to the freezing point of the whole fish, ice inoculation at temperatures below the p.f.p. results in mortality. Thus, at times, the waters of 2J + 3KL are potentially lethal. Investigations have shown that cod eggs and early larvae can survive such conditions because of the ice impermeability of their outer coverings (chorion and epithelial tissue), and the developmental state of certain vulnerable tissues (e.g. gills). In common with many teleost species living at high latitudes, juvenile and adult Atlantic cod are able to occupy potentially lethal habitats by producing antifreeze proteins in response to low temperatures. These lower the animal’s freezing point and possibly also protect against cold-damage at the cellular level. We report on how data on the physiology of northern cod antifreeze production can be used to (a) interpret distribution patterns of wild cod within the temperature field; (b) infer the recent thermal history of wild adult cod and hence, distribution within the available temperature field; (c) monitor (in the laboratory) any changes in antifreeze capacity within a geographical area as a possible indicator of stock composition or distributional changes.

Article from Marine Science Symposia Vol. 198 - "Cod and climate change". Symposium held in Reykjavik, 23-27 August 1993. To access the remaining articles please click on the keyword "MSS Vol. 198".

History

Series

ICES Marine Science Symposia

Volume

198

ISSN

2708-9216