of the Fishery Board for Scotland. 



55 



The total number in the six years, 1896-1901, during which push- 

 netting was carried on, amounted to 142,880,000, but a deduction must be 

 made for a small amount of loss which occurred during transit, and which 

 cannot be well estimated. The fry, as a general rule, were very lively 

 when liberated, and could be observed swimming in the water in a 

 natural way, but occasionally, when the temperature of the water in the 

 vessels in which they had been carried was higher than usual, the move- 

 ments of some of them were more feeble. 



After the fry are liberated they lead a pelagic life, that is to say, they 

 swim about suspended in the water and are carried about by it, if it is in 

 movement, and, as already stated, the duration of this period is somewhat 

 over four weeks. At the end of this time they settle on the sandy 

 beaches in shallow water, as little, completely, or almost completely, 

 transformed flat-fishes, and they may be fouud in such localities from the 

 hitter part of May onwards. The spawning period of the plaice naturally 

 existing in Lochfyne was found to correspond closely with the spawning 

 period in the pond at the hatchery, and there is no means of 

 discriminating between the young plaice derived from the fry put into 

 the loch and those derived from eggs which were spawned naturally in 

 the neighbourhood. The only way of determining the effect of the 

 addition of fry on the abundance of the young plaice found on the 

 beaches was by making a series of observations in a regular and 

 systematic way to ascertain their numbers, as described below, in years 

 when fry were added and in years when fry were not added, and when, 

 therefore, the number of the young plaice was derived from local 

 spawning. As already stated, fry were added in each of the seven years 

 1896-1902, while no fry were added in the six years 1903-1908. The 

 observations to determine the abundance of the young plaice on the 

 beaches were made in each of the years, with the exception of 1902, so 

 that there are observations in six successive years when plaice fry were 

 put into the loch and in six successive years when none were put in. 



In order to ascertain the number of the young plaice on the beaches 

 various methods were at first tried. A fine-meshed ground seine was 

 employed at various parts of the loch, but the results were unsatisfactory ; 

 it frequently got caught on stones, &c, on the beach and was torn, and 

 comparatively few plaice were taken, so that this method was abandoned. 

 A method which would probably have been satisfactory was the use of a 

 small-meshed shrimp-trawl net, and this was also tried, but it was found 

 that it could not be used in the shallow water in Lochfyne, near enough 

 to the tidal margin, which is frequented by the young plaice, and it had 

 to be given up. A specially-constructed trap-net was also tried, but 

 without success, and the method which was found to give the best results, 

 and the one adopted, was a shove- or push-net, like the similar net used 

 in some places for catching shrimps, and of the following dimensions : — 

 Length of wooden scraper, 3 feet 6 inches ; breadth of same, 3 inches ; 

 height of iron frame, 20 inches ; length of net, 7 feet 6 inches ; mesh of 

 end part, about 7 mm. in diameter; length of pole, 10 feet. Certain 

 localities were selected, after trials had been made, and the net was 

 pushed along the bottom at each " station " for a certain length of time, 

 usually two hours, in a foot or two of water and at low tide, when the 

 young plaice are found near the margin in greatest numbers. Several of 

 the stations which were at first made use of were subsequently abandoned, 

 as Lowburn, Cairndow, Otter Spit, because it was found that the 

 numbers obtained were small ; and whereas at first the push-netting was 

 made in various months of the year, it was found necessary later for the 

 same reason, to limit the work to the summer months, and the comparison 



