Terceiro: The statistical properties of recreational catch data off the northeastern U.S. coast 



661 



MRFSS 1996 samples 



LL 



Bluefish 



0123456789 



LiL 



Summer 

 flounder 



0123456789 



Atlantic 

 cod 



0123456789 



ilL 



All 

 species 



0123456789 

 Catch number per hour (including zero catches) 



Figure 3 



Marine Recreational Fishery Statistics Survey (MRFSS) 

 1996 sample data for bluefish, summer flounder, Atlantic 

 cod, scup, and all species, Maine to the Florida east coast: 

 catch number per hour (including zero catches). The 9 fish 

 interval is a "plus group" because it includes totals for larger 

 intervals. 



1 



MRFSS 1996 samples 



LL 



Bluefish 



^ F- : . ^ 



0123456789 



Ll 



Summer 

 flounder 



0123456789 



LL 



Atlantic 

 cod 



0123456789 



Scup 



5 6 



Ll 



8 9 



All 

 species 



0123456789 

 Catch number per hour (positive catches only) 



Figure 4 



Marine Recreational Fishery Statistics Survey (MRFSS) 

 1996 sample data for bluefish, summer flounder, Atlantic 

 cod, scup, and all species, Maine to the Florida east coast: 

 catch number per hour (positive catches only). The 9 flsh 

 interval is a "plus group" because it includes totals for 

 larger intervals. 



able and index of abundance. Modeled in this way, the 

 negative binomial model is expected to provide year-effect 

 coefficients very close in absolute value to the unstandard- 

 ized, mean simulated catch per trip of the true underlying 

 negative binomial distribution because no other classifica- 

 tion effects are present to account for variance from the 

 unstandardized mean. The deviance of the year coefficients 

 provided by the models, assuming the other error distribu- 

 tions, then provides an indication of the degree of model 

 misspecification because virtually all the estimated vari- 



ance in this particular exercise is due to model (process) 

 error, except for the small amount generated by the random 

 draw from the starting probability distributions. 



MRFSS standardized indices of abundance, 1981-98 



The potential effect of the assumed error structure on the 

 calculation of standardized indices of abundance was fur- 

 ther explored with empirical examples using the 1981-98 

 MRFSS time series of catch-per-trip rates (zero catches 



