NO. 3534 EURYTEMORA — WILSON AND TASH 571 



was recorded and foiir other species of Eurytemora were found (table 2), 

 all of which range from brackish to fresh waters. Of these, E. com- 

 posita and E. raboti were not collected again in Cape Thompson sam- 

 ples, but since they are known to be widely distributed in diverse bodies 

 of water along the northwestern Alaskan coast, they may well occur in 

 unsampled ponds or pools of the area. Whether populations are estab- 

 lished in inshore-offshore waters is unknowm but both have been 

 recorded from coastal continental bodies of water of high salinity 

 (Mohr et al, 1961; Holmquist, 1963; Heron, 1964). Since ovigerous 

 females and developmental stages of both species were found in the 

 lagoon in 1960 on several dates, it w^as sm'prising not to find them in 

 1961 samples. The other tw^o species of 1960 samples, E. canadensis 

 and E. gmcilicauda, are both highly characteristic of waters of very 

 low salinity and commonly range into fresh waters. E. gracilicauda 

 occurred in very small niunbers on only two different dates in 1960, 

 and its absence in 1961 suggests it may have been a straggler washed 

 into the lagoon from nearby pools. 



The sparsity of numbers of individuals of species such as E. cana- 

 densis, and the lack of knowledge of occurrence of other species 

 throughout the season, did not make the collections of value for Hfe 

 cycle studies. However, observations of the populations of £'./oi'6o/a 

 from the lagoons north of Cape Thompson indicated that they were 

 reproducing. Collections in July contained ovigerous females with 

 developing ova, accompanied by all copepodid stages, suggesting the 

 possibility that this species could produce two generations dm-ing 

 favorable seasons. Aiautak Lagoon is very large (about 8 km. in 

 length), and the single collection, a littoral tow from the south end, 

 may give an incomplete indication of its calanoid species composition. 

 E. foveola has not yet been found in fresh water (Wilson collection), 

 but its occiu-rence in lagoons of low, variable salinity and association 

 with other species of Eurytemora that are known to range from 

 brackish to fresh waters, suggest a greater eiu-yhalinity than indicated 

 by the presently known occurrences. 



Crustaceans other than calanoid copepods were at times abundant 

 in the lagoons, especially Cyclops spp. and Daphnia spp. (Johnson, 

 1961; Hilliard and Tash, 1966). Both of these freshwater genera 

 are recorded throughout literature from brackish waters along sea- 

 coasts (examples can be found in Giu-ney, 1933; C. B. Wilson, 1932; 

 Lagerspetz, 1958; Carpelan, 1964). Some species are tolerant of low 

 salinities and of changing conditions throughout the season. The 

 almost universal tendency to consider them as genera confined to 

 fresh water may be misleading when attempting to characterize 

 coastal bodies of water by their faunal elements. In some regions, 

 the absence of freshwater calanoid genera is probably more significant 



