The effect on the stock of the capture of undersized fish. The haddock population of the North Sea plateau
The present communication is restricted to a consideration of the changes which have taken place in the haddock population of the North Sea plateau during the last decade.
A census of the moving and ever-changing population in this extensive area during the period under review has been obtained by a combination of three methods :-
- The collection of statistics and measurements of fish caught in the region and landed at British ports.
- Ichthyometrical observations made at sea on commercial vessels by the Ministry of Fisheries (England) Measurers to assess the proportions of unmarketable sizes of haddocks in the total catches from different grounds.
- Periodic trawling surveys of the principal haddock grounds with Standard Otter Trawl by the Scottish Research Vessel ’’Explorer” to amplify the market statistics and to obtain data with regard to the abundance and distribution of demersal haddocks of small sizes which normally escape capture by the ordinary commercial fishing gear.
The ideal aimed at has been a monthly censusof the densities and distributions of the several age classes which make up the total demersal haddock population.
Inludes 3 appendices:
A) The Magnitude of the Destruction of Haddock of Unsaleable Sizes.(by A. B.),
B) A Comparison of the Vigneron-Dahl Trawling Gear with the Ordinary Otter Trawl in the Haddock Fishery, (by A. B.), and
C) The Food and Feeding Habits of the Haddock, by Alfred Ritchie, B.Sc
Reports of the proceedings of a special meeting held on June 24th 1932, at Copenhagen; 'The Effect upon the Stock of Fish of the Capture of Undersized Fish'.
This publication is part of Rapport et Proces-Verbaux des Reunions Vol. 80. To see all other articles in this volume, please click on the keyword "RPVR Vol. 80".
