RING DEPOSITION IN THE OTOLITHS OF 

 LARVAL PACIFIC HERRING, CLUPEA HARENGUS PALLASI 



Michael D. McGirk 1 



ABSTRACT 



The first normal ring in the sagittae of Pacific herring, Clupea harengus paltasi, larvae is deposited at the age 

 of complete yolk absorption. The rates of deposition of subsequent rings in four groups of larvae that were fed 

 daily ranged from 0. 1 2 to 0.96 rings per day, and only two of the four groups had a daily pattern. Larvae that 

 were starved from hatch deposited one normal ring on day 6 posthatch, but all ring deposition stopped 

 thereafter. The starvation of subgroups of larvae after 7 days of feeding and after 25 days of feeding produced 

 deposition rates that were not significantly different from those of the parent feeding groups. The average 

 rates of normal ring deposition were positively correlated with the average rates of growth in length. Daily 

 ring deposition in herring larvae <20 mm long occurs in populations with an average growth rate equal to or 

 higher than 0.36 mm per day. 



Rings or increments in the otoliths of fishes have 

 been used to age wild larvae of several species 

 (Ralston 1976; Kendall and Gordon 1978; Methot 

 and Kramer 1979; Townsend and Graham 1981; 

 Lough et al. 1982; Victor 1 982). This method has two 

 assumptions: 1) The first ring is deposited at a fixed 

 age in each species, and 2) the rate of ring deposition 

 is constant at 1 ring/d. Evidence from studies of ring 

 deposition in enclosure-reared larvae of the Atlantic 

 herring, Clupea harengus harengus, (Geffen 1982; 

 Lough et al. 1982); northern anchovy, Engraulis mor- 

 dax, (Brothers et al. 1976); and English sole, 

 Parophrys vetulus, (Laroche et al. 1982) indicates 

 that these two assumptions may not be true in first- 

 feeding larvae that are starving or growing slowly. 

 The deposition of subsequent rings may be 

 significantly < 1 ring/d. This paper reports that the 

 first ring is deposited at a fixed age in herring larvae 

 and that this age is coincidental with the age at com- 

 plete yolk absorption. It also confirms that the subse- 

 quent rate of deposition is not always daily but that it 

 is positively correlated with the rate of growth in 

 body length. 



MATERIALS AND METHODS 

 Experimental Groups 



The batch experiments reported here were part of a 

 research program on culturing Pacific herring larvae. 

 Several different container sizes, temperatures, and 

 prey types were employed (Table 1). Six groups of 



Table 1.— The experimental groups of Pacific herring larvae and 

 their rearing conditions. 



'Institute of Animal Resource Ecology, University of British 

 Columbia, Vancouver, B.C., Canada V6T 1W5. 



Pacific herring larvae were reared from the egg: Four 

 were fed daily from hatch, one was starved from 

 hatch, and one was terminated 3 d after hatch before 

 food was offered. Two additional starving groups 

 were formed from subgroups that were removed from 

 feeding tanks after 7 d of feeding and after 25 d of 

 feeding and then starved to death. 



Rearing Conditions 



Three groups, 1980A, 1980C, and 1980D, were 

 raised from eggs in 50 1 circular aquaria in April-June 

 1980. The eggs were laid on the walls of a holding 

 tank by adult herring that had been captured in the 

 Strait of Georgia by personnel of the Pacific Biologi- 

 cal Station, Nanaimo, B.C. Therefore, the eggs came 

 from the lower east coast stock (Taylor 1964). After 

 1 4 d incubation at 7°C, the eggs were hatched and the 

 larvae of 1980A and 1980C were transferred to the 

 rearing aquaria. The mean (±1 SD) temperature of 

 these tanks during the rearing period was 12.1° + 

 0.9°C. The 1980A group was fed from hatch to the 



Manuscript accepted September 1983. 

 FISHERY BULLETIN: VOL. 82, NO. 1, 1984. 



113 



