Page:The Zoologist, 4th series, vol 1 (1897).djvu/432

404 and this is likely to yield substantial data to clear up several of the knotty fish problems. McIntosh kept a record for a year of those pelagic fauna found in St. Andrew's Bay, and the monthly variation is most interesting and instructive. He compares the whole to a spindle, the thick mass corresponding to May-July, therefrom tapering on either side to the ends=January. To these surface forms, as a whole (plants and animals), Hensen has applied the technical term "Plankton" (πλαγκτός, wandering). He believes the economical food yield of the ocean can be statistically determined by quantity. Without here questioning his theory, one doubted by Haeckel, it certainly is more obvious that there is an intimate interdependent relation between marine life and seasonal fish numbers. This through plants furnishing pabulum to invertebrates, and these again to piscine groups. To pursue the links in the chain further, the plant profusion is determined by meteorological conditions, and we have arrived at physical causes more within our ken, and probable after results determinable beforehand. Thus step by step are we likely to arrive at reasons for the annual gluts or dearths of fish, early or lateness of seasonal appearance, food migrations, &c. The more pressing or immediate interests of fisheries' industries, meanwhile, have not been lost sight of by the scientific inquirer. Much has already been accomplished towards ascertaining the limits of sexual maturity in both sexes, and the vexed questions of trawling and temporary closure of areas have received due attention. Into these I do not propose to enter other than by pointing out the assumption (a fashion revelled in by the younger biologists) that our fishing is producing a stunted race of flatfish(?).

The institution of Sea-fish Hatcheries, so extolled in America, is yet on its trial in this country. Opinions thereon are divided, the balance being rather in favour of those who maintain the Scotch verdict of "not proven." It is questionable whether the working of a hatchery could be made profitable or not. The weak point in the Dunbar hatchery is liberation only in the fry stage. To remedy this defect, what in contradistinction may be termed "nurseries" are suggested. In these, with larger enclosed