16 DEPARTMENT OF THE NAYAL SERVICE 



6 GEORGE V, A. 1916 



records of catches with memoranda of date, locality, and depth. Eecords sufficiently 

 accurate are in fact kept in the ship's log book, at least in some cases, and it should he 

 possible to arrange with some of the great companies for the tabulation of these data 

 so as to make them available for future reference. Statistics of the aggregate catches 

 are easily obtained, but no detailed list of fishing stations accompanies them. Perhaps 

 the organization of a system of marine fishery statistics, including list of stations, 

 depths, methods of fishing, kinds of fish caught, dates, and observations on the weather 

 and currents, would be the first "step towards a reasonable grasp of the state of the 

 fishery from year to year. The difficulty here would be to ensure accurate statements 

 of depth and locality because the owners of vessels operating in neutral waters would 

 not feel disposed to give exact and gratuitous information merely to encourage the 

 others. Moreover, the fixing of positions by the charts as they stand could, in many 

 cases, only be a rough approximation. Nevertheless the alleged depletion of once 

 productive banks requires some such scrutiny as that here suggested before it can be 

 explained. 



The artificial propagation of halibut in spawning ponds is a colossal experiment 

 which might be tried in order to give an earnest of the endeavour on the part of the 

 pcnentific departments to do something of direct economic value for the fishery. It is 

 certain that nothing can be accomplished in this way without considerable expenditure, 

 and nobody could guarantee positive and successful results. The cultivation of the plaice 

 is a straightforward procedure offering no insuperable difficulties. It is only necessary 

 to collect mature fish of both sexes and keep them in captivity under usual precautions 

 of water-circulation, temperature, and food-supply, until spawning occurs. The turbo t 

 offered greater difficulties which have been overcome in the experimental stage. In 

 February, 1907, Dr. E. Anthony, Assistant Director of the Marine Laboratory in St. 

 Vaast-la-Hougue, procured ten adult turbots which he placed in three large hatching 

 basins, the largest having a capacity of 300 cubic metres. At the end of a few weeks 

 the captive turbot began to take food. They were fed once a week with large pieces of 

 plaice at the rate of half a fish the size of the hand to each turbot, a designedly moderate 

 allowance. To keep the basins free from putrefying food-substances, they put in, as 

 scavengers, a conger eel and a dogfish long since accustomed to captivity. The 

 turbots began to spawn in July. The brood stock should be captured six months before 

 breeding. If taken only a few weeks before spawning time they would be likely to 

 exhibit the phenomenon of ovular retention to which they would succumb. Five con- 

 secutive spawnings were observed on July 18, 21, 28, 29, and August 3. There were 

 thousands of eggs in each lot, all normal and fertilized. Only limited numbers were 

 gathered by plankton nets and transferred to the incubating apparatus, an essential 

 feature of which is continual agitation of the water by a suitable mechanism to keep 

 the eggs free from sediment and thus to prevent asphyxiation. Hatching occurreTl 

 in six to eight days after spawning, and artificial feeding by carefully sifted plankton 

 administered daily was commenced two to three days after hatching. The yolk sac 

 disappeared fourteen to fifteen days after hatching, and the critical stage was passed 

 about the eighteenth to twentieth day. [E. Anthony: La piscifacture du turbot au 

 lab. mar. du Museum (Saint-Vaast-la-Hougue) Bull. Mus. Paris t. XIII, pp. 557-559, 

 1908. Translated and presented before the Fourth International Fishery Congress 

 held at Washington, U.S.A. September 22nd to 2Gth, 1908: Bull. Bur. Fish. XXVIIL 

 Doc. No. 686, Washington 1910.] 



Pending the inauguration of this great experiment, efforts need not be relaxed to 

 continue the work already begun. To do this effectively a vessel, properly equipped for 

 special service, should be chartered or commissioned to rmdertake explorations, not 

 merely to locate fresh halibut grounds on the west coast, but to record observations 

 on the state of maturity of halibut throughout the year, especially during late autumn, 

 winter, and early spring, and to make determined efforts to discover the pelagic eggs 

 by means of the deep sea tow-net. It i& difficult to see what more or what else can bo 

 done to promote the interests of the fishery, except the compilation of statistical tables. 



