REPRODUCTION OF NORTHERN ANCHOVY, ENGRAULIS MORDAX, 



OFF OREGON AND WASHINGTON 



Joanne Lyczkowski Laroche and Sally L. Richardson' 



ABSTRACT 



Mean relative fecundity of 21 anchovies from the northern subpopulation off Oregon and Washington 

 was 826 ±49 oocytes per g ovary-free body weight, or 720 ±40 oocytes per g total body weight. These 

 estimates are higher than those for the central subpopulation and may represent a racial difference 

 between the two subpopulations. Sexual maturity is not reached in most anchovies off Oregon and 

 Washington until the third summer (age II). The smallest anchovies found in spawning condition were 

 104 mm (male) and 107 mm (female) standard length. Overall male and female ratio of anchovies before 

 and after spawning was about 1:1, but males outnumbered females 2.6;1 in regions of active spawning. 

 Degeneration and apparent reduced growth among yolked oocytes prior to and after release of one 

 batch of oocytes may limit the number of anchovy spawnings per season off Oregon and Washington. 



Ovarian maturation is described from direct observations of whole oocytes including both normally 

 developing and degenerating oocytes and from oocyte size-frequency distributions. 



Sexually mature and immature anchovies off Oregon and Washington are segregated during the 

 summer spawning season with mature fish occurring offshore beyond the continental shelf and 

 immature fish occurring in nearshore coastal waters, bays, and estuaries. In winter and spring 

 anchovies of all sizes occur together in nearshore coastal waters. 



The northern anchovy, Engraulis mordax Girard, 

 occurs along the west coast of North America from 

 Cape San Lucas, Baja California, to the Queen 

 Charlotte Islands, British Columbia (Miller and 

 Lea 1972; Hart 1973). Within this range three sub- 

 populations (northern, central, and southern) 

 have been defined based on meristic characters 

 (McHugh 1951) and blood serum proteins (Vroo- 

 man and Paloma^). The central subpopulation, in- 

 habiting the general region between San Fran- 

 cisco, Calif., and Punta Baja, Calif., currently 

 supports major fisheries and has been extensively 

 studied (see most recent review, Huppert et al.^). 

 The northern subpopulation, inhabiting the re- 

 gion north of San Francisco to British Columbia, 

 supports only minor seasonal bait fisheries (Hup- 

 pert et al. footnote 3) and has been little studied 

 (Richardson in press). 



In 1975 we initiated a study to assess the size of 

 the stock of E. mordax occurring off Oregon and 

 Washington by egg and larva survey Knowledge of 



'School of Oceanography, Oregon State University, Corvallis, 

 Oreg.; present address: Gulf Coast Research Laboratory, East 

 Beach Drive, Ocean Springs, MS 39564. 



^Vrooman, A. M.. and R A. Paloma. 1975. Subpopulations 

 of northern anchovy, Engraulis mordax mordax. Southwest 

 Fish. Cent., NMFS, NOAA, Adm. Rep. LJ-75-62, 10 p. 



^Huppert, D., H. Prey A. MacCall, G. Stauffer, and O. Mathi- 

 sen. 1977. First draft — Anchovy fishery management 

 plan. 119 p. + append. Pacific Fishery Management Council, 

 526 S.W Mill St., Portland, OR 97201. 



individual fecundity (the number of eggs matured 

 as a group and spawned at one time) is essential 

 for this method of stock assessment. Three previ- 

 ous estimates of northern anchovy fecundity, one 

 for the northern subpopulation off British Colum- 

 bia (Pike 1951) and two for the central subpopula- 

 tion (MacGregor 1968; Hunter and Goldberg 1980) 

 differed widely in methods and results. Pike's es- 

 timate of fecundity based on counts of all oocytes 

 >0.20 mm was 1,369 oocytes/g total body weight. 

 MacGregor 's estimate based on counts of only the 

 most advanced, nonhydrated, yolked oocytes 

 (^0.50 mm) was 574 oocytes/total body weight, 

 and Hunter and Goldberg's estimate based on 

 counts of ripe, hydra ted oocytes was 389/g ovary- 

 free body weight. 



This study was prompted by the discrepancy 

 between estimates of northern anchovy fecundity 

 in the northern and central subpopulations and 

 the general lack of information on other aspects of 

 northern anchovy reproduction off the Oregon- 

 Washington coast. Our primary objective was to 

 determine anchovy fecundity in the northern sub- 

 population. Additional objectives were to examine 

 length and age at sexual maturity, sex ratio, 

 spawning frequency, ovarian maturation, sea- 

 sonal gonadal condition, and patterns in geo- 

 graphic distribution related to the reproductive 

 cycle. 



Manuscript accepted January 1980. 

 FISHERY BULLETIN: VOL. 78. NO. 3, 1980. 



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