Inputs in a Fishery — Fishing Time 



The abstract production function refers to 

 outputs and inputs per unit of time. The unit of 

 time is undefined. When using annual vessel 

 data, we have to note the fact that the vessels 

 are not utilized for the same amount of time 

 and standardize for this. 



In the simple case, an economist would prefer 

 to use days absent from port as a measure of 

 fishing time rather than days fishing. If a 

 fisherman is an economic maximizer, he will 

 attempt, ceteris paribus, to maximize his gross 

 revenue per day at sea and will plan his fishing 

 strategies accordingly. Under this assumption, 

 the fisherman may or may not fish when or 

 where his expected catch is higher. 



The theory is not clear as to how time should 

 enter the production function. Two basic 

 specifications are possible: 



(1) x = D'^f(l,k J), or 



(2) x = D'f(l,kj) 



There are theoretical reasons that could justify 

 the use of either. Equation (1), with D'^, can be 

 justified if we hypothesize that the fishermen 

 makes trips of varying length. Therefore, we 

 would want to find the marginal contribution 

 of an extra day at sea. Equation (2), with 

 D', can be justified if we hypothesize that all 

 inputs are being used to produce output all the 

 time, so that the relationship is strictly linear. 

 Experiments were run initially in both forms, 

 but the second form was abandoned for what 

 may have been specious reasons. If further work 

 is done the alternative specification will be 

 tested more fully. 



Capital — The Vessel Characteristic 

 Variables 



The abstract production function has a vari- 

 able called capital. This represents the di- 

 mensions of the equipment being utilized. In 

 fishing, the individual firms and many of the 

 characteristics of their capital are identifiable 

 and measurable. 



Vessel size has been recognized as a deter- 

 minant of catch and is explicitly recognized in 

 most of the productivity measures in use. 

 Beverton and Holt (1957) related gross tonnage 



to fishing power, and the Inter- American Tropi- 

 cal Tuna Commission (lATTC) focuses on the 

 capacity of a vessel's freezers (Shimada and 

 Schaefer 1956). 



Other researchers have noted that there are 

 other measures of vessel size that are correlated 

 with output, among them horsepower and length. 

 Gulland (1956) and Noetzel and Norton (1969) 

 experimented with production functions that 

 included both tonnage and horsepower. Their 

 results showed that these variables may make 

 an independent contribution to output. In 

 fisheries, the possibility of independent con- 

 tributions should not be overlooked because 

 there may be a tendency for vessel configurations 

 to be changed in such a way that fishing power 

 is increased. This happens especially with horse- 

 power relative to gross tonnage as old engines 

 are replaced and also as new vessels are built. 



The role of horsepower in the trawl fleet 

 appears to be that the larger the engine, the 

 larger the net that can be dragged, the faster 

 the net can be dragged, or the deeper the water 

 that can be fished. In this type of fishery, the 

 profit-maximizing skipper will adjust his net 

 to obtain the "best" results. Although it has 

 been noted that trawlers do not often use the 

 full power of their engines, a larger engine 

 increases the number of possibilities a skipper 

 can consider when deciding where to fish and 

 what to fish for. 



In a seine fishery, the role of horsepower is 

 less clear, except that, ceteris paribus, higher 

 horsepower increases the "search power" of 

 the vessel. A better measure of this search 

 power than horsepower would appear to be 

 running speed. The only way to obtain this 

 information is by interview or sea trials. 



Hull constiniction is an identifiable parameter 

 of a vessel. Throughout the U. S. fisheries, there 

 has been an increasing tendency to build new 

 vessels of steel rather than wood, in spite of the 

 extra initial cost. One would presume, then, 

 that there are lower operating costs for steel, 

 or that it is more "productive." It is possible 

 to test for the effect on productivity of a wood 

 hull by creating a dummy variable that takes 

 on the value "one" if the hull is wood and 

 "zero" otherwise. 



The last capital input variable that was con- 

 sidered was age of the vessel. Most people would 

 consider older vessels less productive, ceteris 



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