Table 3. — Copepod species in zooplankton samples. Gulf of Maine coastal waters, 196A 



Species 



Common species (>50/lOClm.3) 



Calanus finmarchicus (Guimerus) . . 



Pseudocalanus mlmitus (Kroyer) . . . 



Centropages typicus Kroyer 



Temora longicomis (Muller) 



Metridia lucens Boeck 



Oithona simllis Glaus 



Acartia longiremis (Lilljeborg) . . 



Tortanus discaudatus (Thompson & 

 Scott) 



Less numerous species (<50/l00m. ) 

 Centropages hamatus (Lilljeborg). 



Calanoid sp . immature 



Eurytemora herdmani Thompson and 

 Scott 



Mean 

 number/ 

 100m. 3/ 

 station 



2,368 

 618 

 407 

 242 

 163 

 136 

 106 



65 



25 

 12 



10 



Species 



Less numerous species--Cont. 



Metridia long a (Lubbock) 



Acartia clausi Giesbrecht 



Eurytemora affinis (Poppe) 



Acartia sp . immature 



Cyclopoid sp 



Oithona spinirostris Claus 



Diaptomus mlnutus Lilljeborg 



Euchaeta norvegica Boeck 



Candacia annata (Boeck) 



Anomalocera patersonil Templeton. 



Harpac-^coid sp • 



Undinopsis similis Sars • 



Mean 



number/ 

 100m. V 

 station 



6 



5 



3 



2 



1 



0.73 



0.48 



0.42 



0.29 

 0.17 

 0.04 



BETWEEN- YEAR COMPARISONS, 1963 and 1964 



Zooplankton volumes 



Areal trends in zooplankton volumes were 

 similar in 1963 and 1964 (fig. 6). Volumes were 

 compared between areas within each year by the 

 Mann- Whitney U-test. In both years volumes 

 were significantly higher (P<0. 05) in the west- 

 ern areas than in the central and eastern 

 areas. Significant differences were found be- 

 tween central and eastern volumes in 1963, but 

 not in 1964 (fig. 6), This between-year dif- 

 ference may have been related to the trains i- 

 tional character of the central sector, located 

 between areas with high and low volumes. 



Mean seasonal volumes are plotted by area 

 in figure 7 for both years. Seasonal trends 

 were similar in the western and eastern 

 areas: in the western area volumes increased 

 from a winter low to a sumnner peak and de- 

 clined in the fall; in the east, volunnes reached 

 a spring peak from a winter low and declined 

 in sumnner. The trend was reversed in the 

 central sector, where winter-fall volumes de- 

 creased in 1963 and increased in 1964. Com- 

 parison of volumes between years by the Mann- 

 Whitney U-test revealed significantly lower 



P < 0.05) in 1964 in the west 

 e*^, and in the central areas 



seasonal values 



(spring and ouftA 



(winter and sunnmer). Volumes in the eastern 



area were similar in those years (fig. 7). 



Zooplankton groups and species 



During the 2 years, 12 major groups (sea- 

 sonal mean > lOO/lOOnn.-^) of zooplankton were 

 collected. Five of thenn--copepods, clado- 

 cerans, appendicularians, pteropods, and 

 chaetognaths--w e r e holoplanktonic forms; 

 seven were meroplanktonic--cirriped larvae, 

 fish eggs, crustacean eggs, decapod larvae, 

 brachyuran larvae, annelids, and gastropod 

 larvae. Large swarms of meroplanktonic forms 

 occurred during the spring (cirriped larvae), 

 summer (decapod larvae and fish and crusta- 

 cean eggs), and fall (brachyuran larvae). This 

 swarming occurs during the breeding periods 

 of these forms, the onset of which is largely 

 under the influence of local environnnental con- 

 ditions. Copepods were the dominant forms 

 during all seasons in both years. The curves 

 of copepod abundance were similar for winter 

 and spring, but differed during summer and 



