of the Fishery Board for Scotland. 



sands from year to year, and detailed records were taken of all the con- 

 ditions likely to influence the quantity of fish captured on each occasion. 

 The principal conditions in this respect were found to be (1) the state of 

 the sea — whether smooth or rough on the day of trawling and during the 

 preceding days ; (2) the transparency of the water ; (3) the direction and 

 strength of the wind ; and (4) the state of the atmosphere — whether bright 

 sunshine or cloudy, foggy, and dull. Owing to the free north-easterly 

 exposure, the prevailing northerly to easterly winds during the autumn 

 and winter months cause the sea to be very rough on these sands for the 

 greater part of that time ; and in this kind of weather the whole locality 

 was sometimes found to be almost deserted of fish. The effect of such 

 disarrangement could be observed for a couple of days after the sea had 

 subsided. But after a storm (or heavy rains) the transparency of the 

 sea-water on this coast is always greatly reduced, and remains so for 

 several (4 to 8) days afterwards if calm weather and neap tides happen 

 to follow. Under these conditions the fishes in the shallow water would 

 not so readily observe the approach of the trawl in time to make their 

 escape, and rich hauls were then always made. When the water was 

 clear and calm, and the sun bright, a considerable number of fish could 

 be seen gliding away from the boat and the trawl when working in the 

 shallow water (from 6 to 15ft.), and very probably a certain number 

 would also escape in this way when trawling was made at a greater 

 depth. Another circumstance that influenced the quantity of fish 

 captured was the speed of the boat, which was affected by the strength 

 and direction of the wind. Owing to the frequent chances in these 

 various conditions, and their strong influence on the number of fish 

 captured, it would be necessary to examine sands thus situated at very 

 frequent intervals and for a long period (years) before reliable statistics could 

 be procured with regard to the changes in the actual abundance of fish there. 

 But while the records of the trawling conducted during the one year 

 cannot be used as a definite standard in this respect, they furnish some 

 interesting results in regard to the main object in view; they show how 

 the different sizes of plaice were found at various depths, according to the 

 prevailing physical conditions and seasons of the year, but what is of 

 still more importance — the fishes captured on each occasion were found 

 to be separable into certain groups, representing the fishes hatched in the 

 different years. 



[Table. 



