Porter: Temporal and spatial distribution and abundance of eggs and larvae of Hippoglossoides elassodon 



655 



A B 



172° 168° 164 160 156 152 148' 144 172= 168° 164 160 156 152" 148° 144 



168° 164° 160° 156 152° 148" 168" 164 160° 156 152' 148'W 



C D 



172° 168 : 164° 160° 156 152° 148° 144° 172° 168° 164 160= 156 152° 148° 144° 



168° 164° 160° 156° 152° 148 168° 164° 160° 156° 152 148°W 



egg abundance per 10 m ; 



0-10 



] 10-50 ZZI 50-100 



&£i 100-200 



I =■ 200 



Figure 6 



The geographic distribution of flathead sole (H. elassodon) larvae in the western Gulf of Alaska 

 during months of the spawning season. (A) mid- to late April. (B> mid- to late May, (C) early 

 to mid-June, (D) mid- to late June. 



Smith 2 ), which correlates with the period when eggs 

 were collected in the present study. Peak spawning oc- 

 curred from early to mid-May. and by the end of June 

 spawning was nearing completion. Larval abundance 

 peaked from early to mid-June in the southern portion 

 of Shelikof Strait. In late July, late-stage flathead sole 

 larvae were the most abundant of larval fish collected 

 in the Gulf of Alaska between the Semidi Islands and 

 Unimak Island (Brodeur et al., 1995). Flathead sole 

 larvae have also been found on the east side of Ko- 

 diak Island during the summer (Kendall and Dunn. 

 1985). 



Laboratory observations of the changes in density of 

 flathead sole eggs during development are inconsistent. 

 Results of one study showed that egg density decreased 

 throughout development to hatching (Alderdice and 

 Forrester, 1974). Another study found that up to 24 

 hours before hatching the eggs floated at the surface of 



a container and then sank to the bottom and hatched 

 (Miller, 1969), indicating that density had increased 

 late in development. A field study of the vertical distri- 

 bution of Atlantic halibut iHippoglossus hippoglossus) 

 eggs in Norwegian fjords showed that later stage eggs 

 had a higher density (and were found deeper) than 

 earlier egg stages (Haug et al., 1986). Results from the 

 present study support the findings of Miller (1969). in 

 that the density of flathead sole eggs in the present 

 study appeared to increase near the time of hatch- 

 ing. For the larvae of both the arrowtooth flounder 

 (Atheresthes stomas) and Pacific halibut {Hippoglossus 

 stenolepis), small larvae were found deep and larger 

 sizes migrated towards the surface (Bailey and Pic- 

 quelle, 2002). In the present study, flathead sole larvae 

 had a similar vertical distribution pattern indicating 

 that after hatching in deep water they rise to near the 

 surface to feed. 



