Figure 2. — Mean seasonal volumes of zooplankton in Gulf 

 of Maine coastal waters, 1967 and 1968. Solid line is for 

 1967, and dotted line for 1968. 



10 



^ 6 



1967 

 H = 19 04 P, <0 00l 



1968 

 H = 15-68 P, <0-00l 



WEST 



CENTRAL 



EAST 



Figure 3. — Mean annual volumes of zooplankton for each 

 of the areas investigated in Gulf of Maine coastal waters 

 in 1967 (solid line) and 1968 (broken line). Kruskal- 

 Wallis H values given are for among-area comparisons. 



from a high in the west to a low in the east 

 (fig. 3), Differences in station volumes among 

 the areas were tested with the Kruskal-Wallis 

 analysis of variance, and in each of the years 

 the areal decrease in abundance was signifi- 

 cant {P< 0.001). 



Group and Species Composition 



Copepods are the predominant zooplankters 

 in coastal waters. In different seasons they 

 constituted from 98 percent of the total zoo- 

 plankton (winter 1968) to 41 percent (summer 

 1967). Twelve other groups (taxa) constituted 

 more than 1 percent of the zooplankton in each 



Table 1. — Sample volumes per 100 m. -^ of water strained 

 at each sampling station in three areas along the 

 coast of the Gulf of Maine, 1967 and 1968 



'[Kruskal-Wallis H and probability values are listed 

 for each area by season. See figure 1 for location 

 of stations and areas] 



Year, area, 



and station 



number 



Winter 



Spring 



Summer 



9.08 

 63.28 



5.69 

 21.81 



9.91 



11.22 

 10.72 



3.73 



1.42 



12.45 



5.21 



1.26 

 8.00 

 1.49 

 0.09 



1. 

 0, 

 0. 

 2, 



7. 

 <0. 



,48 

 88 

 ,39 

 73 



94 

 008 



.89 

 .48 

 .94 

 .57 



42.18 



22.10 



9.80 



16.05 



8.94 

 4.11 

 1.11 

 1.13 



0.45 

 0.40 

 0.31 

 0.48 



9.84 



< 0.008 



3.96 

 > 0.104 



1.31 

 1.98 

 3.07 

 2.43 



4.22 

 4.40 

 2.74 

 0.90 



0.93 

 2.43 

 1.97 

 0.97 



2.19 

 > 0.104 



Autumn 



1967: 

 West: 



1 0.91 



3 2.44 



4 4.34 



5 ^33.56 



Central: 



9 0.57 



12 0.28 



13 0.70 



W I') 



East: 



17 0.15 



18 0.01 



19 0.62 



21 0.29 



H value 7.48 



P value <0.010 



1968: 

 West: 



1 10.32 



3 4.12 



4 9.94 



5 7.71 



Central: 



9 0.55 



12 4.33 



13 10.12 



14 1.72 



East: 



17 1.33 



18 3.06 



19 9.75 



21 3.62 



H value 2.88 



P value > 0.104 



■"■ Mostly euphausiids. 



2 No sample obtained. 



year (table 2); five were holoplanktonic (appen- 

 dicularians, chaetognaths, cladocerans, eupha- 

 usiids, and pteropods) and seven were mero- 

 plantonic (brachyuran larvae, cirriped larvae, 

 crustacean eggs, crustacean nauplii, decapod 

 larvae, fish eggs, and gastropod larvae). The 

 seasons of abundance of these groups varied 

 between years. The holoplankters were most 

 numerous in spring 1968, when all except the 

 cladocerans were at their annual peak in abun- 

 dance. In 1967, in contrast, four of the six 

 groups--appendicularians, chaetognaths, cla- 

 docerans, and euphausiids--were most abun- 

 dant in summer. Among the meroplankters, 

 cirriped larvae were most numerous in spring 



5.81 

 2.87 

 2.67 



1.47 



0.19 

 1.98 

 0.87 

 2.50 



0.38 

 0.24 

 0.11 

 0.16 



7.54 

 < 0.011 



2.92 

 2.55 

 7.77 

 3.99 



6.43 

 5.29 

 1.66 

 6.23 



(^) 

 0.83 



( = ) 

 0.76 



4.42 

 > 0.103 



