FISHERY BULLETIN: VOL. 82, NO. 2 



and maintenance, crew shares, payroll taxes, and 

 packing charges. Fuel consumption by vessel 

 class, for which primary data were unavailable, 

 was estimated according to the following relation- 

 ship: 



EC n = WC; (TLITLj) 



* (*<,•*«,•) 



where Y, 



X„ = 



N„ = 



IN 



estimated number of gallons ( 1 gal = 

 3.79 1) used per year by vessel class i. 

 actual number of gallons (1 gal = 

 3.79 1) used in year; by vessel class i. 

 number of vessels in vessel class i 

 in yearj. 



The nets, supplies, and repairs and mainte- 

 nance variables were similarly adjusted like Y- to 

 account for unequal numbers of vessels in the 

 sampling years. These variables were deflated into 

 real terms, using the industrial price index, and 

 the weighted average was determined. From the 

 weighted average of the 5 yr for which data were 

 available, adjusted nominal values were deter- 

 mined for the other years. Crew shares were esti- 

 mated at 33% of value of catch. Packing charge 

 was set at $0.10 per pound (0.454 kg) of shrimp 

 landings. 



Fixed costs include insurance, depreciation, 

 interest, and opportunity cost. Reported data 

 were used to determine fixed charges for over- 

 head items, while charges relating directly 

 to investment — depreciation, insurance, and 

 interest — were calculated in nominal dollars for 

 new vessels. Overhead values for years that data 

 were not available were calculated using the in- 

 dustrial price index in the same manner as with 

 variable cost. 



Insurance charges were set at 47c of new vessel 

 cost. The standard straight-line formula was used 

 to determine depreciation. In this study the ter- 

 minal value of the vessel was calculated in two 

 ways: 1) at 100% of original cost, and 2) at salvage 

 value at the end of 1980. The market rates, which 

 prevailed over the years, were employed in deriv- 

 ing the cost and returns budget. 



where WC , 



RCy 



EC, 



7 N U 



RC, 



1 

 j 



N, 



and 



TL } = 



TL = 



RC u = 



AC u = 



N;; = 



ACyKTLi/TL). 



estimated catch by vessel class 



i for year j where j = 1971, 



1972, ...,1980. 



Texas landing's for year j, = 



1971,1972, ...,1980. " 



average Texas landings for the 



1971-80 period. 



real catch of vessel class i in year 



j for the 5 yr vessel data were 



available. 



actual catch of vessel class i for 



year j for the 5 yr vessel data 



were available. 



number of vessels of class i for 



year j for the 5 yr vessel data 



were available. 



Exvessel 3 prices per pound of shrimp were ad- 

 justed according to the formula given below using 

 the average value from the National Marine 

 Fisheries Service data for Texas and that from the 

 survey to generate exvessel prices for those 5 yr 

 that data were not collected. 



AP, 



{A, - B) + TP / 



where AP, 



TP, 



AI 



B 



= adjusted exvessel price per 

 pound (0.454 kg) of shrimp for 

 vessel i in yearj. 



= Texas prices as reported by the 

 National Marine Fisheries 

 Service for year j, where j = 

 1971, ...,1980. 



= average exvessel price per 

 pound (0.454 kg) of shrimp for 

 vessel i over the 5 yr data 

 were available. 



= average exvessel price per 

 pound (0.454 kg) of shrimp 



Revenue 



Catch relationships were estimated for years for 

 which no data were available by utilizing the fol- 

 lowing formulation: 



3 It is recognized that exvessel price of shrimp is greatly influ- 

 enced by seasonal fluctuation in local supply as well as the size 

 composition of catch (Caillouet and Patella 1981). However, this 

 study implicitly accounts for such trends by employing primary 

 data collected for 1971, 1973, 1974, 1975, and 1977. Therefore, the 

 price represents a weighted average between the various shrimp 

 sizes. 



366 



