Muter and Norcross: Distribution, abundance, and growth of Theragra chalcogramma 



587 



also observed in nearby Prince William Sound in May 

 1989 (Norcross and Frandsen 1 ). Larval concentra- 

 tions inside the fjord in early May 1989 approached 

 those found in the dense larval patch in Shelikof 

 Strait in some years. In most years abundances of 

 early larvae in Shelikof Strait range from to 1,000 

 larvaem" 2 (Kendall et al., 1987; Kendall and 

 Picquelle, 1990), compared with 60-575 larvaem -2 

 in this study. However, in peak years, abundances in 

 Shelikof Strait exceed the 1989 estimates for Resur- 

 rection Bay by one to two orders of magnitude, with 

 10,000 larvae-m -2 in 1981 (Bates and Clark 6 ). Lar- 

 val concentrations in Funka Bay, Japan, decrease 

 from >5,000 larvaem -2 at some stations in January 

 to 200-400 larvaem -2 in early April (Nakatani, 

 1988). For the Bering Sea, typical abundance esti- 

 mates range from 10 to 100 larvaem 2 distributed 

 over a very large area (Incze et al., 1984). In Auke 

 Bay, Alaska, the observed abundances were much 

 lower with maximum densities of 3-15 larvae-m -2 

 (Haldorson et al., 1989a). 



In ichthyoplankton samples taken in Resurrection 

 Bay in the upper 30 m in 1988, maximum densities 

 ranged from 0.8 larvaem -3 at RES 1 to 4.1 larvae-rrr 3 

 at RES 4 (Smith et al., 1991), translating into abun- 

 dances per unit area of 24 larvae-m -2 and 124 

 larvae-m -2 respectively. How- 

 ever, these abundances may 

 be underestimates, since only 

 the upper 30 m were sampled 

 by Smith et al. ( 1991 ), where- 

 as our study found high 

 abundances below 30 m, par- 

 ticularly in the outer basin of 

 the fjord (Fig. 3). Additional 

 samples were collected in 

 Resurrection Bay in late 

 April and early May 1991. 

 Abundances were similar to 

 those estimated for 1989 

 (Muter, unpubl. data). The 

 available data from 1988 to 

 1991 suggest that larval 

 walleye pollock are consis- 

 tently found in Resurrection 

 Bay. The observed abun- 

 dances are close to those re- 

 sulting from the dense spawn- 



ing aggregations found in Shelikof Strait, Alaska, and 

 Funka Bay, Japan (Kendall and Nakatani, 1992). 

 Since the spatial extent of the spawning area in the 

 vicinity of Resurrection Bay is unknown, total abun- 

 dances cannot be compared at present. 



Larval size and age distribution 



Larvae from the shallowest samples at stations RES 

 1 and RES 2 were significantly larger and older than 

 those at the other stations. Larvae from the shal- 

 lowest tows may not be representative of the popu- 

 lation as a whole because of changes in vertical dis- 

 tribution with age. Thus we also pooled larvae from 

 all tows at each station for between-station compari- 

 sons. Some bias may remain because of inconsisten- 

 cies in the depth sampling regime, but the results 

 were almost identical to those obtained when only 

 shallow samples are used. There is clearly a differ- 

 ence in size and age between larvae at stations RES 

 1 and RES 2 and larvae at all other stations. This 

 observation is consistent with the hypothesis that 

 larvae are transported into the fjord and accumu- 

 late inside the inner fjord basin. A length-frequency 

 distribution for all larvae collected at each station 

 (Fig. 8) shows a multimodal length distribution and 



6 Bates, R. D., and J. Clark. 1983. 

 Ichthyoplankton off Kodiak Island 

 and the Alaskan Peninsula during 

 spring 1981. NWAFC Proc. Rep. 

 83-89. Northwest and Alaska 

 Fisheries Sci. Center, NMFS, 

 NOAA, Seattle. WA, 105 p. 



