Humoral immune parameters in Atlantic cod (Gadus morhua L.) II. The effects of size and gender under different environmental conditions.

The effects of size and gender on several humoral immune parameters in cod were examined under different environmental conditions. Serum samples were collected from wild cod of different sizes. Two samplings were undertaken: In the spring in relatively cold waters off the north west coast of Iceland and in the fall in relatively warm waters off the west coast of Iceland. Most of the parameters increased with increasing cod size, except the haemolytic activity which decreased. Higher serum protein levels were seen in cod sampled in the fall than in the spring. In cod sampled in the spring there was an apparent difference between specimens < 75 cm in length and the larger specimens with respect to haemolytic activity and iron concentration. None of the parameters were influenced by the gender of the cod.