FISHERY BULLETIN: VOL. 74, NO. 4 



null hypotheses resulted in no decision. The data 

 from Table 2 indicate that the apparent variation 

 does occur in these two cases (stratum 1 in both 

 subareas 2A and 4A) as well. 



The homogeneity (2) of the polychaete assem- 

 blage between strata, in a given subarea, in a given 

 season was also examined using chi-square tests 

 (a = 0.05, 12 df). Five of the 12 null hypotheses 

 were rejected (i.e., subarea 4A in the winter, 

 subareas IB, 2A, and 3A in the spring, and subarea 

 IB in the summer). A no decision result was 

 reached in the remaining cases. 



Bivalves 



The sampling data collected on the bivalve 

 populations in Garrison Bay are given in Table 3. 

 The data are organized as follows: 1) Protothaca 

 staminea, Venerupis japonica, and Saxidomus 

 giganfeus were grouped as one into the Veneridae; 

 2) Macoma incom^picita, M. irus, and M. nasuta 

 were grouped as one into the Tellinidae; 3) Tran- 

 sennella tantilla, CUnocardium nuttalli, Mya 

 arenaria, and Mysella fumida were considered 

 individually; and 4) Macoma secfa was considered 

 apart from the Tellinidae because of its usual 

 occurrence in clean sandy environments. 



The size and the number of sampling units in 

 this study were generally inadequate for sampling 

 most mature bivalves. As a consequence, hypoth- 

 eses for small bivalves, such as T. tanfilla and M. 

 tumida, are best represented by the data in this 

 study. Indeed, large densities of T. tantilla were 

 found in all four subareas, with the largest 

 numbers in subarea 3A, and M. tumida was found 

 in large numbers only in subarea 4A. 



The north-south bivalve distribution, as con- 

 structed from these data, is somewhat different 

 from that found in the polychaetes. The data in 

 Table 3 show that the subareas may be ranked in 

 descending order with respect to the total 

 numbers of individuals as follows: subareas 3A 

 and IB and subareas 2A and 4A are about the 

 same. However, occasional seasonal reorderings 

 do occur. The high densities in subarea 3A are 

 probably due to the presence of large numbers of 

 T. tantilla. In terms of the number of species 

 present, subarea IB generally ranks highest and 

 the remaining three subareas are almost 

 indistinguishable. 



Differences in the bivalve distributions within a 

 season, on like-numbered strata, and between 

 subareas were examined using chi-square tests 



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