ABUNDANCE OF CONNECTICUT RIVER SHAD 



249 



When the catch per net-day fished is determined 

 for each type of gear fished separately for each year 

 shown in table 2, and the averages for the 11 years 

 are obtained from the catch-per-net-day-fished 

 values, it can be seen that haul seines took an 

 average of 1.6 times as many fish per day's fishing 

 as drift gill nets, and pound nets took an average 

 of 1.3 times as manj 7 fish per day's fishing as drift 

 gill nets. For the population of fish subject to 

 capture by the types of gear used in the fishery, 

 haul seines and pound nets are, respectively, 60 

 and 30 percent more efficient than gill nets. An 

 adjustment is necessary before the catch per 

 fishing-day effort can be determined, because the 

 effort of a drift gill net fished 1 day is not com- 

 parable to that of a haul seine or a pound net 

 fished 1 day. In this study a drift gill net is 

 defined as a standard fishing unit. The fishing 

 power of a standard fishing unit (s. f. u.) is the 

 ability to capture hi 1 day a certain fraction of 

 the fish present in the Connecticut River; for a 

 standard fishing unit (a drift gill net), the relative 

 fishing power is taken as unity. The fishing power 

 of the average haul seine is 1.6 times that of the 

 average drift gill net, and it is therefore equal to 

 1.6 standard fishing units. A pound net is equiv- 

 alent to 1.3 standard fishing units. The unit of 

 effort is defined as a drift gill net which fishes one 

 day; this will be termed a standard-fishing-unit 

 day. Therefore, a haul seine which operates one 



day is equivalent to 1.6 standard fishing unit days, 

 and a pound net which operates one day is equiv- 

 alent to 1.3 standard-fishing-unit days. 



The total number of standard-fishing-unit days 

 a season is a measure of the total fishing effort 

 expended and is given for 1938 and for the period 

 1942 to 1951 in table 3. The numbers of days 

 fished by haul seines and pound nets have been 

 converted to slandard-lishing-unit days by using 

 the conversion factors, 1.6 and 1.3. 



Table 3. — Fishing effort, by gear, in standard-fishing-unit 

 days, 1938 and 1942-51 



1 Based on conversion factor, 1.6; 



2 Based on conversion factor, 1.3. 



DETERMINING FISHING EFFORT FOR 

 1935-37 AND 1939-41 



Table 3 does not include data for the years 1939, 

 1940, and 1941, since the original reports were not 



