Ix 



Thirty'third Anmml Report 



of the observations of preceding years, and also in the Moray Firth 

 with reference to the closing of the waters there to the operations of 

 trawlers. The special statistics of the catches of the line-boats in the 

 Moray Firth have been collected monthly through the Fishery Officers 

 as before, and the old trawling stations of the s.s. " Garland " have 

 been examined with a beam trawl by the s.s. " Goldseeker," as 

 frequently as circumstances allowed, and at dates corresponding as far 

 as possible with those of former examinations, both Avith the beam- 

 trawl and with the otter- trawl. A report on these investigations and 

 on the statistics is in course of preparation. 



The fish-cultural work at the Hatchery at the Bay of Nigg was con- 

 tinued in the spring last year throughout the spawning season of the 

 plaice, and is described below. A number of requests for plaice fry 

 were received on behalf of the fishermen at various parts of the coast, 

 and these were as far as possible complied with, consignments being 

 forwarded to Peterhead, Fraserburgh, Cruden Bay, and Rosehearty, 

 and the fry liberated off the coast in the neighbourhood of these 

 localities. The fishermen at various places on the coast have shown 

 interest in the fish hatching work, which they believe has helped to 

 improve the plaice fishing in their neighbourhood. During the last 

 thirteen years a total of over 245,000,000 of the fry of the plaice have 

 been liberated along the coast of Aberdeenshire. 



THE HATCHING OPERATIONS. * 



In the course of the year several consignments of live plaice, 

 caught in the Moray Firth, were brought to the Hatchery by the 

 research steamer " Goldseeker," and placed in the large spawning 

 pond. As always happens, a proportion of the fish died later, owing 

 to injuries received in the process of capture, but the stock of adult 

 fishes at the commencement of the season was fairly large. As ex- 

 plained at length in former Reports, the adult plaice of both sexes are 

 retained in a large tidal pond into the water of which the eggs are 

 shed, and where they are naturally fertilised during the spawning 

 season. The floating eggs are collected at intervals by means of 

 a large fine-meshed net, and transferred to the Dannevig hatching 

 apparatus, where they are kept until the larval fishes are born. The 

 period of incubation varies with the temperature of the water. Hatch- 

 ing, as a rule, takes place in the early part of the season, namely, in 

 January and February, in from three to four weeks, and about a week 

 sooner in the latter part of the season, in April and May. The larval 

 fishes are retained in the apparatus until the yolk-sac is nearly 

 absorbed, when they are transferred to the sea in suitable localities. 



The first collection of eggs was made on 19th January, and the 

 last on 1st May, more than half the number being obtained in March. 

 The estimated number of eggs collected from the spawning pond in the 

 season was 21,810,000, and the estimated loss in the process of hatch- 

 ing in the apparatus amounted to 2,980,000, or about 14 per cent. 

 Thus, the estimated number of fry obtained and liberated in the sea 

 was 18,830,000. The fry were distributed in six lots between the 20th 

 J'ebruary and the 8th May. The great bulk of the fry was liberated 

 off Peterhead and Fraserburgh, and considerable numbers at Rose- 



