FISHERY BULLETIN: VOL. 87, NO. 1 



to a change in increment number of 1.102 incre- 

 ments. This compared favorably with the samphng 

 interval, 1.025 days, and is consistent with predic- 

 tions based on daily increment formation. 



Physical Oceanography 



Current patterns in the spawning area were inves- 

 tigated in June-August 1985 by 1) release of 

 surface drift cards near the spawning grounds, 2) 

 deployment of a surface drifter drogued at 50 m for 

 24 hours, and 3) examination of surface isotherms 

 as indicated by a shipboard thermosalinograph. 



A total of 2,250 surface drift cards were released 

 during the 1985 spawning season. Cards were re- 

 leased in four lots, two at each of two points (Fig. 

 1), located immediately north and south of the 

 spawning ground. A set of cards was released at 

 each point on 21 and 22 July and again on 11 and 

 12 August. 



A drifter was deployed at 0800 h on 19 July south 

 of the spawning area at a site at which large 

 numbers of newly hatched larvae were collected Oat. 

 42°43.4'S, long. 145°04.0'E) (Fig. 1). The drifter 

 consisted a 8.5 m parachute drogue suspended at 

 a depth of 50 m below a large surface buoy fitted 



I440E 145° 146° 147° 148° 



SB'S 



40' 



45' 



130°E 



140° 



150° 



Figure 3.— Total catches of larval Macruronus novaezelandiae, pooled by 

 transect, for 1984 and 1985, standardized per 1,000 m^ of water filtered. 



34 



