GROWTH OF NORTHERN ANCHOVY, 

 ENGRAULIS MORDAX, LARVAE IN THE SEA 



Richard D, Methot, Jr. and David Kramer' 



ABSTRACT 



Northern anchovy larvae froml2 samples collected at :3.0°-16.2° C in the Southern California Bight 

 were aged using daily growth increments in sagittal otoliths, and growth rates were calculated from 

 size at age data. In nine samples, growth rate at 8 mm was very similar, ranging from 0.34 to 0.40 mm 

 per day. Growth in the other three samples ranged from 0.47 to 0..55 mm per day. There was no 

 correlation between growth rate and temperature within this set of field samples, but the range of 

 growth rates was similar to the range expected from laboratory rearing experiments in this tempera- 

 ture domain. In no case was growth in the sea as slow as growth in the laboratory on severely limited 

 rations. Anchovy larvae which obtain enough food to survive apparently obtain enough food to grow 

 rapidly. 



The presence of daily growth increments in some 

 hard tissues of various plants and animals has 

 been known for several decades (Neville 1967i. 

 Despite the fact that fish otoliths have been 

 examined for annual growth marks throughout 

 this century (Blacker 1974), daily growth incre- 

 ments were only recently identified in fish (Pan- 

 nella 1971). The daily nature of these increments 

 was verified in the laboratory by Brothers et al. 

 (1976) using marine fish larvae. Taubert and 

 Coble ( 1977) showed that increment formation in 

 centrarchids is linked to the diel light cycle, not a 

 feeding rhythm. Although studies have been con- 

 ducted on the gross growth of otoliths (Degens et 

 al, 1969; Mugiya 1974, 1977) the physiological 

 mechanism responsible for daily growth incre- 

 ment formation in fish is unknown (Simkiss 1974), 

 Regardless, daily growth increments provide the 

 ecologist with a tool for determining age and 

 growth of specimens from the field iStruhsaker 

 and Uchiyama 1976). 



The objective of this project was to estimate 

 growth of larval northern anchovy, Engraulis 

 mordax, in the sea. Many laboratory studies dem- 

 onstrate that growth of young fish is limited by 

 temperature and ration (Riley 1966; Brett et al. 

 1969; O'Connell and Raymond 1970; Houde 197.5). 

 Because food availability is frequently considered 

 to be one of the major factors controlling larval 

 survival (Gushing and Harris 1973; Jones 1973: 



'Southwest Fisheries Center LaJolla Laboratory, National 

 Marine Fisheries Service, NOAA, P O Box 271, La Jolla, CA 

 92038. 



May 1974; Lasker 197.5; Arthur 1976), growth in 

 the sea may frequently be limited by food. How- 

 ever, when collections of measured larvae are used 

 for indices of spawner abundance or larval mortal- 

 ity studies, growth is assumed to be constant 

 (Houde 1977) or a function solely of temperature 

 (Bannister et al. 1974), Determining growth rates 

 of larval fish in the sea should resolve this con- 

 tradiction between theoretical and applied fishery 

 science. 



Anchovy larvae can be reared to metamorphosis 

 and beyond in the laboratory (Kramer and Zweifel 

 1970; Hunter 1976; Sakagawa and Kimura 1976), 

 Growth in these experiments was described best 

 by the Gompertz growth equation, equation 1 

 (Kramer and Zweifel 1970; Zweifel and Lasker 

 1976), The effect of temperature on embryonic de- 

 velopment and larval growth was incorporated by 

 making the Gompertz gi-owth parameters. .4„ and 

 a, increasing functions of temperature (Zweifel 

 and Lasker 1976; Zweifel and Hunter^). We com- 

 pared the size at age of anchovy larvae in each field 

 sample with that predicted by this temperature 

 dependent model of anchovy growth in the 

 laboratory, assuming that the temperature mea- 

 sured at the time of collection represented the 

 temperature experienced by the larvae through- 

 out their lifetimes. 



Manuscript accepted .lanuarv 1979 

 FISHERY BULLETIN: VOL 77. NO 2, 1979. 



^Zweifel. J. R., and J. R. Hunter Temperature specific equa- 

 tions for growth and development o( anchovy. Engraulis mordax , 

 during embryonic and larval states. (Manuscr. in prep.) 

 Southwest Fisheries Center La Jolla Laboratory, NMFS. NOAA, 

 P.O. Box 271, LaJolla. CA 92038. 



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