The following paragraphs discuss limitations of the data used in this 

 report and of the graphs presented in the species sections. 



Because of the relatively short towing time (0.5 hour), the catches 

 during bottom trawl surveys were low when compared to the catches of 

 commercial vessels. Also, the randomly selected stations did not necessarily 

 fall within areas of high population densities, whereas commercial vessels 

 tend to concentrate in more productive areas. 



The survey catches, however, are comparable from one year to the next 

 when compared on a stratum or strata set basis. When making comparisons or 

 interpreting data, parameters such as the dates of the survey, the trawl used, 

 and the vessel used should be considered. Different trawls were used during 

 spring and autumn surveys. The data from these two time series are not 

 directly comparable without applying fishing power coefficients for the 

 different sizes of the trawls. To date, these coefficients have been worked 

 out for only a few species. No coefficients have been employed in this study, 

 so care should be exercised when making comparisons, particularly since three 

 different trawls have been used during the study period. The primary value of 

 these data is in examining seasonal distribution as deduced from spring and 

 fall cruises and trends over each time series. When the data are used in this 

 manner, abundance changes or trends can be evaluated effectively. 



For two of the figurative reporting formats (length-frequency histogram 

 and the coastline figures depicting young-of-the-year distribution) percent is 

 used in place of absolute or stratified values. This method was used to 

 facilitate computer processing, and to put the voluminous data base in 

 perspective. However, when interpreting the results it should be taken into 

 account that percentages can mask the actual number of animals 



