of landing for recording each trip and listing 

 the quantities of each species landed. Most of 

 the Virginia dealers complied, so that this 

 series is virtually complete for the landings 

 at Virginia ports, which received most of the 

 winter catches each season after 1932. Lesser 

 quantities of scup from the offshore winter 

 fishery are landed at Cape May and Wildwood, 

 N.J., and New York, N.Y., but unfortunately, 

 the records of landed catches at these points 

 are incomplete. Hence, the following discussion 

 of the total yields is restricted to landings 

 at Virginia ports. Because of their magni- 

 tude, it is believed that they depict the general 

 changes in the fishery. 



Although this offshore fishery is too new, 

 and records of its catch cover too short a 

 period (1931-35 inclusive) to establish a rend, 

 they do afford an idea of the fluctuations that 

 have occurred within this short period of 

 five seasons. The total catch of scup has 

 increased since 1931, rising from approxi- 

 mately 1,686,000 pounds in that winter to 

 approximately 3,844,000 pounds in 1935 (figs. 

 3 and 8, table 16). 



Total catch statistics of landings are for 

 the period of November 15 of one year to 

 April 15 of the following year. The fishery, 

 however, takes place mainly in January, Feb- 

 ruary, and March when most of the catch 

 is landed. Hence, with the intention of avoiding 

 confusion, a season is referred to as a single 

 year, for instance, November 15, 1930, to 

 April 15, 1931, is referred to as the winter 

 of 1931. 



Table 16. — Catch and catch per day's fishing, by the winter trawl 

 fishery for scup, sea bass, and fluke, from statistics of land- 

 ings at Virginia ports, 1931-35 



[In pounds] 



^ November 15 of preceding year to April 15, inclusive. 

 ^ January to March, inclusive. 



As might be expected in a new fishery, 

 much of the increase has been due to in- 

 creased fishing effort— the number of boats 

 in the fleet increasing from about 50 in 1931 

 to 80 in 1932, 85 in 1933, 100 in 1934, and 

 about 120 in 1935. Other factors besides 

 increased fishing effort have caused changes 

 in the catch. 



Measurement of fluctuations . — In 

 attempting to measure the magnitude of these 

 changes in the catch of the winter trawl fish- 

 ery, it is necessary to determine some unit 

 of measure based on a fixed amount of fishing 

 effort in order to eliminate whatever effect 

 frequent changes in the amount of gear and 

 fishing time may have on the landings. The 

 selection of such a unit of measure suffi- 

 ciently accurate to depict actual changes in 

 the population was difficult because of the 

 many factors that influence such a figure. The 

 unit computed was the so-called "catch per 

 day's fishing". It was intended to be the actual 

 amount of catch as the result of 1 full day 

 or 24 hours of actual fishing. Some of the 

 factors affecting the accuracy of such a unit 

 are (1) the discarding at sea of fish that the 

 market may consider undersized and unsal- 

 able, together with the lack of accurate rec- 

 ords or reliable estimates of the amounts 

 and sizes thrown overboard; and (2) diversion 

 of fishing effort at times from scup to more 

 profitable and available market species (sea 

 bass, fluke, and croakers). Such diversion is 

 easily accomplished because market fish are 

 more or less confined to certain areas within 

 a few hours' steaming distance of each other 

 (Nesbit and NeviUe, 1935). Diversion fre- 

 quently occurs when fishing for scup is poor, 

 when bad bottom results in too many net 

 tearups, or when prices favor another kind 

 of fish. 



Also, fishing time is lost as a result of 

 net tearups, vessel or equipment breakdowns, 

 and cruising from one part of the ground to 

 another, or to a distant port. Further diffi- 

 culties arise because of differences in the 

 size and power of boats, types of nets used, 

 and mesh size. Annual changes in the fleet 

 Involved the inclusion of vessels that differ 

 from each other in size, power, and catching 

 efficiency. As might be expected in any new 



32 



