APPENDIX F 



Seasonal Abundances and Reproductive Patterns 

 of Zooplankton in Maine Waters 



Eleven species of copepods and nine groups of meroplanktonic species 

 are discussed below, in terms of seasonal abundance and times of reproduc- 

 tion. Some species, such as Eurytemora herdmani and Acartia tonsa, are not 

 dominant in the coastal waters of Maine; however, because of the dominance of 

 these species in estuaries, it is necessary to include them in this section 

 for the sake of comparison. Meroplanktonic forms addressed are either 

 (1) dominant (i.e., abundant), (2) important to the benthic population 

 (i.e., barnacles, molluscs, or polychaetes) , or (3) important predators 

 (i.e., coelenterates of Sagitta elegans ) . 



1. ) Calanus f inmarchicus 



Although Calanus f inmarchicus is the most abundant species in the Gulf 

 of Maine, C_. finmarchicus was not abundant in Penobscot Bay and the maximum 

 in population occurs in late summer and late fall (Bertrand 1977). This 

 species decreased in numbers toward the upper bay (Bertrand 1977) , which 

 indicates that C^. finmarchicus is probably carried into the upper bay from 

 coastal waters. 



In the Gulf of Maine, Fish (1936) reported that the western stock of 

 this species (C^. finmarchicus ) had two major broods, which spawned primarily 

 in March-April and in June- July, with perhaps another spawning season in 

 September. In Penobscot Bay, peak abundances of copepodites were observed 

 in winter and summer, which indicates spawning in fall and early summer 

 (Bertrand 1977). Bertrand (1977) feels that the population of C^. finmarchicus 

 is probably a result of immigration from the Gulf of Maine combined with 

 localized propagation. 



2.) Pseudocalanus minutus 



P^. minutus is widespread in the temperate region of the northern hemi- 

 sphere and is nearly as universal as C^. finmarchicus in the Gulf of Maine. 

 In the Bay of Fundy and in the Gulf of Maine, P^. minutus is second in abun- 

 dance only to C. finmarchicus (Fish 1936), and Bigelow (1926) suggests that 

 it averages about 11% of the copepod stock and generally was 1/lOth to 

 l/5th as abundant as C^. finmarchicus . Pseudocalanus minutus adults in 

 Penobscot Bay exhibit four periods of maximum abundances: midwinter, early 

 spring, late summer and late fall (Bertrand 1977). The largest peak is in 

 late summer. 



In Boothbay Harbor, Pseudocalanus minutus is abundant in all seasons; 

 the major peak of abundance occurs in October, with smaller peaks in February, 

 May, and July-August (Sherman 1976). This pattern is similar to the 



(Continued) 



4-F-l 



10-80 



