On the food of certain gregarious fishes / by R. Knox.

  • Knox, Robert, 1791-1862.
Date:
[1855]
Catalogue details

Licence: Public Domain Mark

Credit: On the food of certain gregarious fishes / by R. Knox. Source: Wellcome Collection.

Provider: This material has been provided by The Royal College of Surgeons of England. The original may be consulted at The Royal College of Surgeons of England.

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    the spawning or recently spawned slate, exercises a striking influence on the quality of certain fishes as food for man. In August some fine herrings were examined in Glasgow (west coast of Scotland); the food appeared to be the ova of some testaceous animal, as the shrimp, but after all, was probably merely Ento- mostraca, exceedingly minute : nevertheless, a few even of these her- rings had been eating the sand-eel. On this coast also, as the herrings get out of order, they take to other food and become insipid and worthless. These observations were repeated on September 27th and October 13th, 1834, at Anstruther, in Fife, and close to the mouth of the Frith of Forth. Of fifteen herrings taken on July 6th, 1838, of three different sizes, the stomachs were filled with Entomostraca: the first were in good order as food. But in winter, in friths, they do not seem to feed; as on February 6th, 1836, of many fresh herrings caught in the Frith of Forth, the stomachs and intestines were found to be empty. Of fifty herrings examined on the 13th of February, 1836, caught in the Frith of Forth, forty-two had the stomachs and intestines empty; four had been feeding on the ova of small fi.shes, and four on a peculiar red substance: in twenty-two others nothing was found. Thus, when caught in bays and friths, the stomach is often quite empty; like the salmon, they are then off their feeding- ground, which is the deep sea. The sexes are usually in equal numbers. On the 30th of November, 1834, my brother remarks, in his journal, that it has been invariably in herrings caught off the Isle of May that he has found the Entomostraca : further up the frith, their stomachs are very generally empty. The Isle of May is close to the German Ocean. On the 4th of December, some herrings taken even now are good; and this, my brother remarks, is invariably the case with the first taken—even in winter. Continuing the examination of these original journals, I find the following entries:— July 6, 1838. Fifteen herrings, taken off Anstruther and dis- sected, gave the following results; the date of capture as above. Largest size.—From snout to centre of tail . . . 1 Of inches. Length to dorsal fin 5J „ „ to extreme margin of gills . . 2| ,. Greatest depth 2f „ Weight 8 oz. XIIT. 2 B