SEA FISHERIES LABORATORY. 



77 



to be caught is the " biological" one of the smallest size 

 which will ensure that the animal has had the chance of 

 reproducing its species once, still, if that is at present 

 impracticable, any limit set by the law would be of some 

 value, as the protection of the immature stages will — 

 other things being equal — lead to a greater number being 

 present of the lowest unprotected size, and, if the rate of 

 capture remains the same, in each size above that, so that 

 there will be an increased number of spawners, and the 

 average size of the species will become greater. If a fish 

 spawns, for example, at 12 inches, and it is not possible 

 to extend protection to that size, it is better to protect it 

 up to 8 inches, say, than not to protect it at all. And if, 

 as the result of this partial protection, the numbers and 

 the average size of the fish are increased it may be possible 

 in the future gradually to raise the minimum catchable 

 size until the " biological " limit is reached. 



Spawning Grounds. 



In last year's report it was recommended that a sys- 

 tematic search should be made with the new steamer for 

 any spawning grounds that exist in the district. One of 

 the places visited, on March 11 and 13, was a sandbank of 

 considerable size situated off the Bahama lightship, about 

 5 miles E.S.E. of Maughold Head, Isle of Man, and 

 having a depth of 8 — 10 fathoms over it (see map). 

 Several hauls of the trawl were taken over this bank and 

 a tow-net was also kept going at the surface to see if 

 there were any floating fish eggs, but no indication was 

 found of any spawning fish or eggs being present. 



The next place tried (on March 13) was the spot known 

 to fishermen as " The Hole," a tongue of deep water run- 

 ning up from the south of the Isle of Man and being a 

 continuation of the deep belt of water which leads in 



