FISHERY BULLETIN: VOL. 81, NO. 3 



Tate and Clelland 1957). Overall larval abundance 

 also varied between transects, IV and V having 

 higher total numbers of larvae than the rest (1,093 

 and 718/1,000 m 3 compared with ca. 250). Offshore 

 displacement and dispersion of larvae had occurred 

 by late April. Larvae were most numerous at the 10 

 nmi station, and many were collected out to 30 nmi. 

 Concordance among transects with respect to rank 

 order of stations was less than in March but still 

 significant {W= 0.43; df= 7,6;P<0.01). Larvalnum- 

 bers were reduced from March. Transects VI and I 

 had the most larvae (418 and 232/1,000 m 3 com- 

 pared with <100 in the others). 



The gradient of larval age along the coast was 

 evaluated by summing abundance of each stage 

 within transects (Fig. 9). March showed no consistent 

 gradient, but there were considerable differences in 

 median stage among transects. Medians for transects 

 V and VI were 3.28 and 3.43, respectively. Others 

 averaged 2.0. By April transects were more uniform 

 in this respect. Median stage was 4.9 with a low of 4.2 

 and high of 5.8. The median increased 2.4 stages 



from March to April. While transects were more uni- 

 form, there was a wider range of stages in April with a 

 slight increase in occurrence of older larvae in more 

 southerly transects (IV to VI). 



Onshore-offshore distribution was characterized 

 by summing stage abundance at equivalent stations 

 between transects for each cruise (Fig. 10). Zoeaelto 

 IV predominated in March and were most abundant 

 within 15 to 20 nmi. By April older larvae were dis- 

 persed outside 5 nmi. 



Field Estimates of Larval Growth 

 Rates 



The two years differed in the rate of change of 

 developmental stage frequency. Development can be 

 followed roughly by successive estimates of the me- 

 dian stage in the pooled samples for each cruise 

 (arrows in Fig. 11). In early cruises of 1971 larvae 

 already were widely dispersed and subject to tem- 

 peratures below 9°C in the whole region (Fig. 5). Cold 

 persisted until late April, and median stage only in- 



E 

 O 

 O 



o 



o 



z 



z 

 < 



z 



OQ 

 < 



19 



MARCH 

 Transect I 



1A 



||li 



ii 



2.3 



■1 



& 



M 



IjLm 



1.7 



Hit 



3.2 



+™H 1 1 1 •- 



l , ! , !,! , ^ , ^ , - 



VI 



I 



111 w 



III IV V 



Larval Stage 



APRIL 



i ^ i^i t i i i i i 



i^i™i™i i i — i — i i i 



("i^i^i i i i — i i > 



IV 



i™i m i™i™i i i — i— i — i- 



{ — i— i — i- 



JLtM 



!  !■! I 



4.2 



 ,1,1, 1,1,1,  ,■,■ 



4.6 



l l ■■■■■- 



1 



4.9 



"i "> 



h 



i" i »i"i*i^i"i" i "i b i' 

 5.8 



M,B, B |BjM|M|B|M| — r«. 



4.9 



■I !    ■■■- 



t10 3 t 



10 

 ■10 -■ 



V " l,n2l 



■i ^i^i — i™ i i — i — i—i — i — 



I ill III IV V VI VII VIII IX X XI 



1 T 8 



i 



4.9 

 No Data 



 i i i — i i i — i — i— i — 



II III IV V VI VII VIM IX X XI 



Larval Stage 



Figure 9.— Stage-specific larval distributions 

 and abundance in March and April 1972. Larval 

 abundance summed by stage within transects. 



464 



