JONES and DKACON ll'H UNITED STATES SHRIMP FISHERY 



species, and commercial tail-weight. The retained 

 catch was reported; no estimate was made of the 

 discarded catch. Landing records for each fishing 

 trip included the total weight of shrimp in each 

 commercial weight category. The landings were 

 recorded in two categories: "mixed" shrimp (pink- 

 spotted, brown, and pink) and white shrimp. In our 

 treatment of the landing data, however, we com- 

 bined the landings of "mixed" and white shrimp. 

 Information on area of catch was not available in 

 the landing records. In addition, processing plants 

 reported total yearly landings of shrimp and aver- 

 age fleet sizes, including both U.S.- and other-flag 

 vessels. 



We estimated total monthly areal catches by 

 adjusting the monthly catches reported by area in 

 logbooks for 1) catches unreported by area and 2) 

 landings unreported in logbooks. For example, the 

 total U.S. catch off northern Brazil (fishing zones 

 78-81) in April 1974 was estimated as follows: 



A' x 



B_ 

 B' 



C 

 C 



where A 



B 



B 



C 



C 



= estimated total catch in zones 78-81, 



April 1974; 

 = catch reported in logbooks for zones 



78-81, April 1974; 

 = total catch reported in logbooks, April 



1974; 

 = total catch reported in logbooks by 



fishing zone, April 1974; 

 = total landings reported in landing 



records, April and May 1974; 

 = total catch reported in logbooks, April 



and May 1974. 



The ratio BIB ' adjusted A ' for the logbook catch 

 that was unreported by fishing zone and the ratio 

 CIC adjusted for the landings that were unre- 

 ported in logbooks. The second ratio used data for 2 

 mo, since catches made in a given month often 

 were landed in both that and the following month. 

 This method resulted in estimates of the total an- 

 nual catches by areas of capture which were 

 within 2% of the total reported annual landings. 

 The logbook sample was not random and the catch 

 off Brazil was probably overestimated, since more 

 vessels probably submitted information when 

 fishing off Brazil than when fishing off the 

 Guianas. However, there was no way to assess the 

 difference in completeness of reporting of vessels 

 fishing different areas. For this reason, estimates 



of catches were not made for smaller subareas. 



The size index was a weighted mean value cal- 

 culated by assigning the values 1, ... 9 to the 

 commercial tail-weight categories >50, . . . <15. 



ANNUAL LANDINGS AND CATCHES 



During the second half of 1972, total landings by 

 U.S. -flag vessels were 5.0 million pounds; in 1973 

 and 1974, they were 13.6 and 9.0 million pounds, 

 respectively (Table 1). Landings of U.S. vessels 

 were 50% and 39% of total international landings 

 in 1973 and 1974. Monthly catches (Table 2) vary 

 slightly from landings since they are estimated 

 values and because catches are often landed in 

 months subsequent to the month of capture. 



To gain a perspective of the entire fishery, we 

 assembled the historical landings of U.S.- and for- 

 eign-flag vessels for 1960-74 (Table 3, Figure 3) 

 and the number of shrimp trawlers by country for 

 1961-74 (Table 4). There was a continuous in- 

 crease in landings from 1960 (3.9 million pounds) 

 through 1968 (27.3 million pounds). The landings 

 declined slightly in 1969 and 1970 to 27.1 and 27.0 

 million pounds, respectively. There was a sharp 

 decline in landings in 1971 andl972 (to 22 million 

 pounds). In 1973 the fishery. attained a maximum 

 catch of 27.3 million pounds. The following year 

 there was a decline in landings to 23.1 million 

 pounds. 



Ninety percent of the landings from 1960 

 through 1974 were made in Guyana (46% ), French 

 Guiana (21%), Surinam (14%), and Trinidad 

 ( 10% ). The remaining landings were made in Bar- 

 bados (6%), Brazil (3%), and Venezuela (1^ ). Na- 

 tional- and foreign-flag vessels landed in Bar- 

 bados, Trinidad, Guyana, Surinam, and French 



TABLE 1. — Landings of shrimp in pounds, heads-off weight, re- 

 ported for U.S. vessels in the Guianas-Brazil shrimp fishery, 

 1972-74. This table is based on data submitted by processing 

 plants; monthly data for January- June 1972 were not available. 



705 



