THE IMPOVERISHMENT OF THE SEA.

A Critical Summary of the Experimental and Statistical Evidence bearing upon the Alleged Depletion of the Trawling Grounds


Marine Biological Association, Plymouth (1895)

Walter Garstang
Naturalist in charge of Fishery Investigations under the Marine Biological Association:
late Fellow of Lincoln College, Oxford



SUMMARY.

I have therefore, in the first place, made an independent examination of the results of the Fishery Board's experiments. It will be seen, in the sequel, that I agree with Professor McIntosh that the methods by which it was sought to demonstrate the observed changes in the fish population of the closed waters were inadequate, and caused the Fishery Board's conclusions to rest upon an insecure basis ; but after eliminating all sources of uncertainty in the methods, I find that the changes in the fish fauna, which were especially emphasised by Dr. Fulton, are capable of abundant verification. There appears to me to be no further room for doubt that during the ten years' closure of St. Andrews Bay and the Firth of Forth against trawlers, there was a decrease of plaice in the closed waters of both areas, and a marked increase of common dabs ; and that in the Forth lemon soles markedly decreased, and long rough dabs increased. These latter species are too scarce in St. Andrews Bay to be worth considering in respect to that area. I concur with Dr. Fulton that the decrease of plaice and lemon soles, in spite of the protection inshore, is most probably to be attributed to the effects of over-fishing by trawlers on the offshore grounds, which causes, as one of its results, a great reduction in the quantity of eggs by which alone the stock of these fish can be maintained, whether on the inshore or offshore grounds. I also agree in part with Dr. Fulton that the increase in dabs and long rough dabs may be attributed to some extent to the protection of the inshore spawners of these species ; but am inclined to attribute a certain and probably a large portion of the increase to the advantage conferred on the dabs by the reduced numbers of their competitors, the plaice and lemon soles. The reported increase of dabs and long rough dabs outside, as well as inside, the closed waters tends to support this view.

In the second place, I have endeavoured to make a fairly exhaustive analysis of all the available statistics, official and unofficial, which deal with the English fisheries. They consist of the following separate items:

1. The actual annual catches of Grimsby sailing trawlers for a nearly continuous period of thirty-three years, from 1860 to 1892 (supplied by Grimsby smack-owners).

2. The weight of fish annually sent inland by rail from the port of Grimsby, and steam, registered at the port, from 1886 to 1899 (from returns provided by the Great Central Railway Company).

3. The weight of fish annually landed by trawlers at the Lowestoft fish-docks, from 1883 to 1898, compared with the gross number of trawling vessels landing at the port (from returns provided by the Great Eastern Railway Company).

4. The total weight of bottom fish annually landed on the various coasts of England and Wales during the decade 1889 to 1898, compared with detailed estimates of the number and catching power of the deep-sea trawlers and liners during the period (from the Board of Trade returns and numerous other sources specified below).

The results obtained from all these various independent sources of information display a melancholy unanimity. Whatever the period—whether ten years or thirty years—and whatever the extent of the fishery—whether the smack fisheries of Grimsby and Lowestoft, the general fisheries of Grimsby, or the entire bottom fisheries of England and Wales, either as an entirety or according to the seas frequented—the average return for each vessel engaged in the fishery, or for each equivalent unit of fishing power, is shown to fall from year to year with none but insignificant fluctuations in the rate of fall.

We have, accordingly, so far as I can see, to face the established fact that the bottom fisheries are not only exhaustible, but in rapid and continuous process of exhaustion ; that the rate at which sea fishes multiply and grow, even in favourable seasons, is exceeded by the rate of capture. The rate of exhaustion is shown to be different for different species of fish. The more valuable flat fishes, plaice and prime fish, show the most marked signs of diminished and diminishing abundance. These differences should obviously be noted, and if possible still further elucidated, in order that the difficulties in the way of remedial measures may be intelligently anticipated and met.

In conclusion, it is with much pleasure that I acknowledge the assistance which I have received in the preparation of this paper from numerous individuals and official representatives, without whose cooperation it would have been impossible to undertake certain parts of this revision of the fishery statistics on anything like so extensive a scale. To Mr. G. L. Alward, of Grimsby, I am under a particular debt of gratitude, not only for the information placed by him at my disposal, but for the frequency with which he has sacrificed time and labour, probably at great personal inconvenience, to respond to my inquiries. I have also been aided by Mr. W. E. Archer, H. M. Inspector of Sea Fisheries, and his colleagues at the Board of Trade ; by Mr. J. W. Towse, Clerk to the Fishmongers' Company ; by the General Managers of the Great Central and Great Eastern Railway Companies ; the Manager of the Milford Docks Company ; Commander Scobell Clapp, R.N., Queen's Harbourmaster of Holyhead ; the Harbourmasters of Neyland, Newlyn, Ramsgate, and Lowestoft ; Mr. Sanders, of Brixham ; Mr. Shepherd, of Plymouth ; Mr. B. J. Ridge, of Newlyn ; Mr. J. W. Turner, of Lowestoft; Mr. R. L. Ascroft, of Lytham ; Mr. W. H. Ashford, Fishery Officer of the North-Eastern Sea Fisheries Committee, Scarborough ; as well as by other gentlemen, the results of whose assistance do not directly appear in the present communication. I desire to express my cordial thanks to all who have co-operated with me in the work.

If errors, either great or small, should be detected in my methods or calculations, I am alone responsible for them ; but I trust that they will be found to be neither numerous nor serious. So far as the methods are concerned, I have endeavoured throughout to base the conclusions as far as possible upon grounds which are capable of verification, and in matters where absolute precision was unattainable, to steer a moderate course in the estimates adopted.