YELLOWTAIL FLOUNDER OFF NEW ENGLAND 



197 



ford fishing fleet usually fished the concentration 

 of yellowtail flounder wherever it was found 

 within the range of the southern New England 

 stock, we believe that our calculation of the catch 

 per unit of effort is representative of that experi- 

 enced by the entire fleet. 



Table 22. — Percent of yellowtail landings from the southern 

 New England stock included in catch per unit-of-effort 

 data 



Table 23. — Catch per unit of effort of yellowtail from the 

 southern New England stock, by year and quarter, 1942-49 



[Averages not weighted) 



The most obvious phenomenon in the resulting 

 catch-per-day data is the pronounced seasonal 

 fluctuation (table 23). In every year (1942-49) 

 the catch per day during the third quarter was 

 greater than in any other quarter. The remain- 

 ing quarters were more variable with the first, 

 second, and fourth leading in one or more of the 

 years. The average landing per quarter for the 

 8 years, 1942 through 1949, was 5,808 pounds of 

 yellowtail per day for the first, quarter; 5,242 

 pounds for the second quarter, 9,480 pounds for 

 the third quarter, and 6,400 pounds per day for 

 the fourth quarter, with an unweighted average 

 of 6,732 pounds for the year. 



This seasonal fluctuation does not hide the gen- 

 eral downward trend of the relative apparent 

 abundance of the yellowtail from 1942 to 1949. 

 The trend is similar in all quarters (fig. 13). The 

 annual average catch per day differs somewhat 

 from the trend in the total landings (fig. 14) : the 

 change in the relative apparent abundance is not 

 so great as the change in quantities landed. This 

 is to be expected from the fleet's habit of con- 

 centrating on a species when it is abundant and 

 of changing to other fisheries when it becomes 

 scarce. Also, a considerable increase in the rela- 

 tive apparent abundance occurred in 1945, which 

 was associated with a decrease in fishing effort 

 and therefore was not accompanied by an increase 

 in the catch. 



The catch per day has been computed also in 

 terms of numbers of fish to provide data which 

 will be used later in the estimation of mortalities. 

 It is of interest to note that the catch per day in 

 terms of numbers of fish landed greatly accentu- 



476995 O— 59 3 



1 Catch (in thousands of pounds) and days fished from interviewed vessels 

 of 26 to 50 gross tons landing more than 75 percent yellowtail on each trip. 



2 Estimates based on average weights from table 20, p. 195. 



3 Includes the catch and days fished times 0.796 of trawlers from 5 to 25 

 gross tons. (See text, p. 196.) 



* Unweighted average. 



ates the seasonal fluctuation because of the tend- 

 ency for yellowtail to run larger in the winter 

 fishery and smaller in the summer. 



