SHENKER: OCEANOGRAPHIC ASSOCIATION OF NEUSTONIC MEROPLANKTON 



a) 



0.4m 



1.05m 



3.50m 



1.0m 



6.0m 



b) 



Figure 2a. — Front view of the neuston trawl; B = inflated 40 cm diameter spar buoys; 



C = cloth collar around mouth of net; R = polypropylene rib lines. 

 Figure 2b. — Side view of the neuston trawl showing construction of the towing bridle. 



Floats were removed for clarity. 



Several very large catches of Dungeness crab 

 megalopae in the neuston trawl were subsampled 

 by volume, with the majority of the megalopae 

 being returned alive to the ocean. Samples from 

 both nets were preserved in 10% formalin/sea- 

 water and sent to the laboratory for analysis. All 

 larval and juvenile fishes were identified to the 

 lowest practical taxonomic level. After extrapo- 

 lating catch sizes from subsample counts, the 

 data were normalized to produce density esti- 

 mates of organisms/1,000 m^^. As an indicator of 

 patchiness of abundant taxa, the coefficient of dis- 

 persion (CD. = S'^/X ) was calculated for the sam- 

 ples in which each taxon was present. 



Hydrographic and meteorological data were 

 collected at each station. Surface water tempera- 

 ture was determined with a handheld bucket 

 thermometer. Water samples were collected for 

 laboratory analysis of surface salinity using a 

 Model 8400 Guildline Autosalinometer. A 200 



mL surface water sample was filtered through a 

 0.3 fxm pore size Gelman A/E glass fiber filter for 

 determination of chlorophyll a concentration. The 

 filters were stored in dessicant over dry ice at sea, 

 and then in a freezer, before acetone extraction of 

 the chlorophyll a and analysis with a Turner De- 

 signs Model 10 Fluorometer. During the daytime, 

 Secchi depths were estimated, using a 30 cm disc, 

 and surface irradiance was measured with a 

 handheld General Electric Model 214 Light 

 Meter. Other data collected included weather and 

 sea state conditions at each station. 



RESULTS 



Hydrographic Data 



The neustonic realm was characterized by dis- 

 tinct temporal and spatial patterns that reflect 

 the highly dynamic springtime oceanographic 



301 



