Doyle et al.: Neustonic ichthyoplankton in the western Gulf of Alaska 



247 



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Cryptacanthodes aleutensis 



O 



Ammodytes hexapterus 



Figure 6 (continued) 



developed larvae are abundant in the neuston mainly 

 at night ( Doyle, 1992 ). They are common in the neus- 

 ton and subsurface zone in the western Gulf of Alaska 

 from winter to summer (Kendall and Dunn, 1985; 

 Rugen 3 ). Mean larval lengths tended to be greater 

 in the neuston, however, and densities were highest 

 in the neuston during late spring and summer. As 

 with many of the other species, A. hexapterus larvae 

 were most abundant during spring in the mid-shelf 

 area from southern Kodiak Island to the Shumagin 

 Islands (Fig. 60). They were scarce to the northeast 

 and seaward of Kodiak Island and southwest of the 

 Shumagin Islands. Kendall and Dunn (1985) and 

 Rugen 3 found them to be more widely distributed in 

 subsurface samples, including high numbers north- 

 east and seaward of Kodiak Island, implying that 

 spawning is widespread throughout the sampling area. 



Multispecies spatial patterns 



Three recurrent groups of larval fish taxa were iden- 

 tified by using Recurrent Group Analysis on data 



from all cruises (Fig. 7). Constituent members of 

 these groups displayed affinity levels of >0.4 with 

 each other. Individual species from these groups were 

 also associated with individual species from other 

 groups, or from outside the groups, at affinity levels 

 of>0.3or>0.4. 



The largest group contained four taxa, Crypta- 

 canthodes aleutensis , Hemilepidotus hemilepidotus, 

 Mallotus villotus, and Stichaeidae, which frequently 

 occurred together in the same samples. A second 

 group comprising Ammodytes hexapterus and 

 Hexagrammos decagrammus, the two most abundant 

 larval species in the neuston, was connected to Group 

 1 via individual linkages among all taxa except 

 Stichaeidae. The result, two groups and their asso- 

 ciated weak linkages, suggested the existence of a 

 loosely affiliated assemblage of larval species in the 

 neuston for this region. 



Pleurogrammus monopterygius and Hemilepidotus 

 spp. belonged to a third recurrent group which did 

 not display any linkages with other species or groups 

 of species. This may reflect the unusual association 



