YELLOWTAIL FLOUNDER OFF NEW ENGLAND 



183 



tant recapture was only 170 miles from the point 

 of release, and the majority of the recaptures 

 were within 50 miles of their points of release. 

 In this respect, movement of the yellowtail is 

 not quite as localized as that of the winter 

 flounder (Perlmutter 1946), but certainly it 

 ranges far less than do such species as the cod, 

 striped bass, and mackerel. 



YELLOWTAIL STOCKS 



The tagging data when considered together 

 with the concentrations of fishing effort provide 

 the basis for delineating the stock of yellowtail. 

 A stock is defined here as the population or popu- 

 lations of yellowtail which occur in a fishing con- 

 centration during a year. In the following 

 paragraphs we delineate the stocks and discuss 

 for the minor stocks the trends in production and 

 problems of intermingling. The discussion of the 

 southern New England stock will be the subject 

 of most of the rest of this report. 



1. Southern New England Stock.— This stock 

 is found between Nantucket Shoals and Long Is- 

 land, chiefly in water 15 to 35 fathoms in depth. 

 It appears to be limited on the southwest by unsuit- 

 able temperature conditions and on the east by 

 the less-favorable shoal waters of Nantucket 

 Shoals and the deep waters of South Channel. 

 The populations intermingle to a large extent, but 

 are not entirely homogeneous. The area is close 

 enough to the scattered small fishing ports to en- 

 able the small trawlers to fish any concentration 

 that they may find. 



2. Georges Bank Stock. — This stock tends to be 

 restricted to Georges Bank by the less-favored 

 deep waters around the Bank. This area is acces- 

 sible to medium and large trawlers, which fish the 

 entire Bank except for a few small areas where the 

 bottom is too rough. For many years the Georges 

 Bank catch of yellowtail flounders was taken 

 either in the winter in the Cultivator Shoals area 

 by vessels seeking yellowtail or incidentally 

 throughout the year on the rest of the Bank by 

 vessels seeking other species of fish. Beginning 

 in 1947, increasing quantities of yellowtail were 

 found on southwestern Georges Bank, and in 1948 

 and 1949 much larger quantities were obtained on 

 southeastern and southwestern Georges Bank 

 (tables 3 and 6). 



Table 6. — Annual United Stales landings of yellowtail by 

 stocks, 1943-49 



[In thousands of pounds] 



' Slight discrepancies occur due to rounding off of the figures. 



Naturally, with a catch increasing so phenom- 

 enally, the question arises as to whether it in- 

 creased because the fish became more abundant 

 in the area or because they had not been previously 

 found. Distribution of the other trawl fisheries 

 on Georges Bank appears to answer the question. 

 The principal fishery here is for haddock, and 

 according to Schuck (1951) the southeastern part 

 of Georges Bank produced 24.4 percent of all the 

 Georges Bank landings of haddock from 1936 to 

 1948, while the southwestern part produced but 

 6.8 percent. The haddock fishery is concentrated 

 in somewhat deeper water than the yellowtail 

 flounder prefers, but nevertheless enough haddock 

 fishing occurs in almost all trawlable areas on 

 Georges Bank that any important concentrations 

 of yellowtail almost certainly would have been 

 discovered. This view is further strengthened by 

 Schuck's observation that the southwestern part 

 of Georges Bank produced 14.7 percent of the 

 haddock in 1944 and 18.9 percent in 1945. From 

 the same investigator we learn that fishing effort 

 on the southwestern part of Georges Bank fell off 

 to 7 percent in 1946, 6.2 percent in 1947, and 4.9 

 percent in 1948. As the yellowtail catches did 

 not increase until 1947, 1948, and 1949 (table 3), 

 the increased yellowtail catches did not coincide 

 with increased trawling for haddock, but followed 

 it about 2 years later. Clearly the yellowtail be- 

 came more abundant in the area after the haddock 

 declined. 



Since the increase in catches of yellowtail on 

 Georges Bank coincided with a decrease in catches 

 from the southern New England stock west of 

 Nantucket Shoals and the tagging results show 

 that migration may occur across the South Chan- 

 nel, part of the southern New England stock of 

 yellowtail may have moved to Georges Bank. The 



