Observations on the size, dry weight and energy content of the eggs of some demersal fish species from British marine waters

• Published in: Journal of Fish Biology
• Main Authors: Hislop, J. R. G., Bell, M. A.
• Format: Article in Journal/Newspaper
• Language: English
• Published: Wiley 1987
• Subjects: Gadus morhua
• Online Access: http://dx.doi.org/10.1111/j.1095-8649.1987.tb05209.x; https://api.wiley.com/onlinelibrary/tdm/v1/articles/10.1111%2Fj.1095-8649.1987.tb05209.x; https://onlinelibrary.wiley.com/doi/pdf/10.1111/j.1095-8649.1987.tb05209.x

The diameters, dry weights and calorific value of the eggs of seven gadoid species (cod, Gadus morhua , haddock, Melanogrammus aeglefinus , whiting, Merlangius merlangus , Norway pout, Trisopterus esmarkii , lythe. Pollachius pollachius , saithe, P. virens , ling. Molva molva ) and one pleuronectid (plaice, Pleuronectes platessa ) were measured. Ling eggs contain an oil globule; the eggs of the other species do not. Preservation in formaldehyde solution caused a small (<4%) reduction in egg diameter but a large (15–30%) reduction in dry weight. There was no significant difference between the dry weights of unpreserved eggs weighed after (a) oven‐drying at 60° C or (b) freeze‐drying. Equations relating the dry weight of unpreserved eggs to unpreserved diameter and to preserved diameter are given for six species, and general equations that may apply to all North Sea gadoids whose eggs lack an oil globule are calculated. The calorific values of the dried, unpreserved eggs of all species except ling were similar (mean 23.19 kJ g −1 , S.D. 1.50) but the value for ling was higher (mean 26.92 kJ g −1 , S.D. 2.29). The estimated energy content (kJ 1000 eggs −1 ) of eggs of each species are tabulated.