54 NATURAL SCIENCE. Jan. 



have made such changes in the conditions of the fishery that it is a 

 risky matter to draw definite conclusions from tlie numerical state- 

 ments at our disposal. The difficulty of dealing with fishery "returns " 

 is still further increased by the want of discrimination between various 

 species, and by the fact that a fish may came into port as a codling 

 and go out as a " Finnon haddock," may " be caught as the head of a 

 catfish and the tail of a monk, and go out as the cheek muscles of a 

 skate." 



Mr. Holt's special attention was directed to the question of 

 immaturity in the fish caught, and he chose out the skipper with 

 whom he made his voyage because he had the reputation of having 

 landed more undersized plaice than any other man in the world. It is 

 pleasing to see that, like the true naturalist he is, Holt soon was on the 

 best of terms with the whole ship's company. We read " by this time 

 I had got to work with tow-nets and microscope, and the antics of 

 copepods and such small deer were a source of constant delight to the 

 crew ... I was able also to introduce my friends to the mystery of 

 artificially fertilising fish eggs, and had hatched out a small family of 

 turbot in a pickle bottle before we got back to port." All this and 

 much else is very pleasing (weather notwithstanding) ; but there is 

 another and very appalling side to such voyages. The modern steam 

 trawler is a terrible engine of destruction, and we find that on a 

 moderate estimate "in a whole year's trawling, on all North Sea 

 grounds, 57 per cent., or more than half, of the fish caught had never 

 had a chance of reproducing their species, and so contributing to the 

 upkeep of the supply." 



In conclusion, Holt attributes the grave deterioration in the 

 North Sea trawling industry to two causes, " (i) an immense destruc- 

 tion by deep-sea trawling of immature plaice and turbot on shallow 

 grounds on the Continental coast, frequented only by immature 

 members of the first species, and chiefly by immature members of the 

 last ; visited also by spawning soles, turbot, and brill ; (2) a serious 

 destruction on our own coast by various methods of long-shore 

 shrimping of immature plaice, and of immature soles, turbot, and 

 brill, in proportion to the abundance of these species," and so on. 

 For the full details of the amount of blame attaching to the various 

 methods of fishing, reference must be made to the report, which 

 includes, last of all, a discussion of proposed remedial measures. 

 Whether or not we all agree with the author in his arguments as to 

 the benefit or the reverse likely to result from various methods, 

 restrictive and otherwise, his carefully thought out conclusions must 

 carry great weight, and must receive the utmost consideration from 

 the District Fishery Committees and other legislative boards. His 

 most important contention is that by the mere imposition of a size 

 limit of thirteen inches on plaice alone, from March 14 to September 30, 

 we should leave the eastern grounds entirely untouched to serve as a 

 nursery for the whole North Sea for plaice, turbot, and to a less 

 extent for brill and soles, and as a spawning haven for soles, brill, and 

 turbot. This appears to be the only practicable method, at present, 

 of checking the depletion of the North Sea grounds and of enabling 

 the fish supply to recover. 



It is deeply to be regretted, in the interests both of science and 

 of the fisheries, that Mr. Holt has been compelled by ill health to 

 give up his important work at Grimsby, and to resign his post as 

 naturalist to the Marine Biological Association. Let us hope that 

 he may soon be enabled to return to his labours with regained 

 strength and fresh vigour. W. A. H. 



