Jellied Condition in the American Plaice Hippoglossoides platessoides (Fabricius)

Publisher Website
Google Scholar
Abstract
On much of the Grand Bank a "jellied" condition in the flesh of many large plaice renders fillets prepared from them unsuitable for the market. The jellied fillets have, on the average (in percentages of total weights), over 4% more water and over 4% less protein than normal fillets. The myo-sin fraction is reduced and the stroma fraction increased in terms of percentage of total nitrogen, and "drip" is greater. Jellied condition is negligible in immature and small mature fish, but occurs increasingly at larger sizes. All very large fish are females, and most of the females above 60 cm in length are jellied. The jellied condition in the Grand Bank area occurs throughout the year. More of the large fish tend to be jellied in waters between -1[degree] and 0[degree]C, and fewer in areas of higher bottom temperatures. From the important eastern Grand Bank area, commercial catches of plaice from shallow waters (31 to 55 fath.) are composed of small fish few of which are jellied, while at increasing depths, down to 100 fath., there is a gradual increase in the size of plaice and in the percentage of jellied plaice. At 113 to 124 fath., with higher temperatures, research vessel catches indicate, for the same fish sizes a smaller percentage of jellied fish than in the colder water at 61 to 87 fath. Microscopic examination indicates less muscle fibre material, much greater waviness of muscle fibres, and more inter-fibre space in jellied than in normal fillet tissues. There is no evidence that sporozoan or other parasites are responsible for the typical jellied condition. The jellied fillets are edible if cut in small pieces before cooking to allow escape of water. During cooking there is considerably more shrinkage in jellied than in normal fillets. It is concluded that the jellied condition is due to protein emaciation caused by the gonads having priority in the use of protein, and by the inability of many large plaice in the colder-water areas to provide for body repair and growth and for the development of sexual products. The Grand Bank jellied plaice are in a new fishing area. The largest plaice should be discarded at sea and intensive fishing will reduce the numbers of large and jellied fish.

This publication has 1 reference indexed in Scilit: