DIMINUTION OF FISH SUPPLY 51 



The evidence which induced this change of view 

 rests partly on experiment, partly on statistics. 

 Although the new view may be correct, none of the 

 older sources of evidence are altogether satisfactory. 

 One charge which used to be made against the trawl 

 that it destroyed the fish-spawn has been dis- 

 proved. The ova of all the prime food-fish, as we 

 have seen, with the exception of those of the herring, 

 float on the surface ; and the herring is a fish that 

 shows no sign of diminishing in number. In 1886 the 

 Scottish Fishery Board began experiments to deter- 

 mine whether the number and size of fish were 

 diminishing on a certain limited area or not. The 

 Firth of Forth and St. Andrews Bay were closed 

 against commercial trawling, and divided into stations. 

 Once a month the ship employed by the Board visited 

 each station and trawled over a given area. The fish 

 taken were counted and measured. For the first few 

 years the results indicated an increase of food-fish ; 

 but, taking a longer period and considering the flat- 

 fishes alone, we find that the numbers of plaice and 

 lemon-sole taken sank from 29,869 for the five years 

 1885-1890, to 28,044 for the five years 1891-1895. On 

 the other hand, the dab, a comparatively worthless 

 fish, had increased from 19,825 to 29,483. 



These figures, it is true, have not been generally 

 accepted as an exact measure of the changes which 

 took place during the period investigated; but inde- 

 pendent criticism has corroborated their general 

 tendency. It looks as if protection had been encour- 

 aging the wrong sort a process not unknown else- 

 where. The explanation possibly lies in the facts 

 adduced by Dr. Fulton that the plaice and lemon-soles 

 spawn only in the deep water outside the closed 

 areas, where they are subject to continuous fishing, 

 with the apparent result of a decrease in the number 

 of eggs and fry inshore ; whilst the dabs spawn to a 



42 



