4-8" 



HOLOPLANKTON MEROPLANKTON 



Copepoda nauplii Polychaete larvae 



Copepoda copepodites Gastropod veligers 



Harpacticoida Bivalve veligers 



Acartia tonsa Barnacle nauplii 



Acartia hudsonica Barnacle cyprids 

 Temora longicornis 



To evaluate comparability of zooplankton collection methods, 

 data collected during the 13-month period when both were in use were 



siibmitted to simple regression analysis. Population density estimates 



3 

 (numbers/m ) of nine abundant taxa from both methods were transformed to 



log (x+1) values, matched by station, collection date, tide, and 

 depth. Two versions of the regression analysis were employed: 1) data 

 were matched where organisms of a particular taxon were captured by 

 either one or both collection methods, and 2) data were matched only 

 where both collection methods resulted in captures. The purpose of the 

 second type of regression analysis was to indicate the position of the 

 axis through the cluster of matched data points, disregarding those that 

 fell directly on the x or y axis (i.e., which included a zero as one of 

 the values in the pair) . The rationale for this exclusion was that when 

 the two methods yielded contradictory results on a presence-absence 

 basis, clearly the method indicating absence was not sampling with any 

 comparability to the other method, due either to differing thresholds of 

 detection between methods or to real heterogeneity in the sampled environ- 

 ment. Simply stated, one method was completely ineffective at capture, 

 regardless of the actual concentrations present. Inclusion of these 

 points merely obscured the relationship between the two methods when 

 both were effective. 



lohthijop lankton 



Daytime ichthyoplankton collections were made monthly from May 

 1971 through May 1972 and from July 1974 through October 1977 (excluding 

 January 1977) with a 1-m diameter plankton net outfitted with either 

 333ym (July 1974 through April 1975) or 505ym (May 1971 through May 1972 



