FISHERY BULLETIN: VOL. 73, NO. 2 



Table l.-Middle Atlantic supply and demand regressions. 



1 R^ and DW refer to the unadjusted coefficient of determination and the Durbin-Watson statistic for autocorrela- 

 tion, respectively. 



2 The formulae used in calculating price and income elasticities are ~^}^ • q and ^ '^ , respectively. In the re- 

 gressions not utilizing logarithms mean values of variables are used to fix the point elasticities. 



5 Quantity and Income are measured in per capita form. 



■^All variables are measured in natural logarithms except tVlSX. 



* Refers to statistical significance at the 0.05 level. 



Table 2.-Delaware Bay supply and demand regressions. 



Predetermined variables 



Endogenous 

 Equation variable Constant h^SX 



Q5 



Statistics' 

 DW 



Elasticities^ 



Price 



Income 



Supply 

 Supply 

 Demand 

 Demand 



Q3 



InO* 

 P 

 InP* 



0.223 

 -1.718 



0.165 

 -18.290 



-0.409 

 (-8.05)* 



-4.317 

 (-5.99)* 



0.003 



(0.22) 



-0.155 



(-0.77) 



0.0003 

 (3.18)* 



2.090 

 (5.04)* 



0.008 

 (2.43)* 



0.407 

 (2.51)* 



-1.169 

 (-2.42)* 



-0.170 

 (-2.51)* 



0.70 

 0.77 

 0.66 

 0.98 

 0.55 

 1.06 

 0.66 

 1.24 



3.4 



4.1 



5.9 



12.3 



iff2 and DW refer to the unadjusted coefficient of determination and the Durbln-Watson statistic for autocorrela- 

 tion, respectively. 



2The formulae used in calculating price and income elasticities are =^^ • q and "gf 'q, respectively. In the re- 

 gressions not utilizing logarithms mean values of variables are used to fix the point elasticities. 

 3 Quantity and Income are measured in per capita form. 

 ■•All variables are measured in natural logarithms except f\/ISX. 

 * Refers to statistical significance at the 0.05 level. 



empirical results of the supply and demand model 

 applied to oyster data for the years 1940 to 1970 in 

 the Middle Atlantic and Delaware Bay regions. 

 Numerical estimates of the coefficients along with 

 t values in parentheses are obtained through the 

 use of either linear or log linear regression 

 analysis and ordinary least squares as the method 

 of estimation. 



In general, parameters have expected signs and 

 are significant for at least the 0.05 level. The 

 coefficient of determination is reasonably high in 

 most regressions indicating that the included 

 predetermined variables explain a large fraction 

 of the variation in the endogenous variables. Since 

 the linear and logarithmic equation forms do not 

 differ greatly there is no evidence of nonlineari- 

 ties. 



In the supply equations the MSX variable 

 displays a strong negative impact on quantity, and 

 is more significant (i.e., larger t values) in the 

 Delaware Bay regressions. Biological evidence in- 

 dicates that the disease had a greater impact on 

 Delaware Bay production than on Chesapeake Bay 



production although Virginia was hard hit during 

 much of the period of analysis. 



Lagged price has a negative and highly sig- 

 nificant impact on supply for the Middle Atlantic 

 region indicating that the depletion effect 

 dominates the effort effect where common 

 property prevails. In contrast the Delaware Bay 

 results indicate that lagged price is not a sig- 

 nificant determinant of supply in a private 

 property right structure. 



In the price (implicit demand) equations oysters 

 display a significant positive income response in 

 most regressions.'^ Oysters thus appear to be a 

 normal good whose demand is likely to grow as 

 consumer income rises over time. Since the price of 

 chickens is a positive determinant of demand in all 

 regressions, the relationship between the two 

 commodities is one of substitution. The negative 

 coefficient for quantity supports the law of 



"Preliminary cross sectional analyses conducted by National 

 Marine Fisheries Service Economic Research Laboratory in- 

 dicate much weaker income effects (and possibly negative) for 

 oysters. 



260 



