FISHERY BULLETIN: VOL 78. NO. 4 



Because of the relatively unfished state of 

 northern anchovy off Oregon and Washington, the 

 lack of biomass estimates, and the potential for 

 fishery development, this study was undertaken to 

 define spawning centers and provide the first pre- 

 liminary estimates of spawning biomass within 

 such defined spawning centers by means of 

 ichthyoplankton survey. Additional information 

 on adult school distributions and another inde- 

 pendent estimate of biomass were obtained by 

 acoustic survey (Smith ). Ecological data on the 

 early life of these northern occurring fish were 

 also examined. Aspects of adult life history, par- 

 ticularly reproduction, are presented in a separate 

 paper (Laroche and Richardson 1981). 



THE NORTHERN SUBPOPULATION 



Northern anchovy occurring north of Cape 

 Mendicino, Calif., compose the northern subpopu- 

 lation of E. mordax, one of three subpopulations 

 (Figure 1) distinguished on the basis of meristic 

 counts (McHugh 1951) and electrophoretic separa- 

 tion of blood serum protein (Vrooman and 

 Paloma ). The central subpopulation occurs 

 primarily off southern California and northern 

 Baja California and the southern subpopulation is 

 off central and southern Baja California. A sepa- 

 rate subspecies, E. mordax nanus, has also been 

 described from San Francisco Bay (Hubbs 1925). 



Compared with the central and southern sub- 

 populations, relatively little detailed information 

 is available on spawning and early life history of 

 northern anchovy in the northern subpopulation. 

 Off California and Baja California spawning sea- 

 sons and locations are well defined (e.g., Ahlstrom 

 1966, 1967; Baxter 1967; Kramer and Ahlstrom 

 1968), eggs and larvae have been illustrated ( Bolin 

 1936; Ahlstrom 1956, 1965; Kramer and Ahlstrom 

 1968), and spawning biomass has been estimated 

 on the basis of larva survey (e.g., Pacific Fishery 

 Management Council footnote 2). 



For the northern subpopulation, information on 

 spawning and early life history had to be pieced 

 together from a number of sources to provide the 

 background for the present study. Based on 

 monthly plankton collections of larvae off Oregon 



^P E. Smith, Southwest Fisheries Center La Jolla Laboratory, 

 National Marine Fisheries Service, NOAA, RO. Box 271, La 

 Jolla, CA 92038, pers. commun. March 1978. 



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

 of northern anchovy, Engraulis mordax Girard. NOAA NMFS 

 Southwest Fish. Cent., Admin. Rep. No. LJ-75-62, 10 p. 



125' 



120° 



115' 



110' 



Figure l. — Geographic ranges (hatched) of the three subpopu- 

 latiiSns (northern, central, southern) of Engraulis mordax (mod- 

 ified from Smith and Lasker in press). Rectangular area outlined 

 off Oregon and Washington shows ichthyoplankton survey grid 

 boundaries for this study. Rectangular area outlined off Califor- 

 nia and Baja California shows approximate boundaries of the 

 principal portion of the CalCOFI survey grid (after Kramer et al. 

 1972). 



(Richardson 1973, see footnote 5; Richardson and 

 Pearcy 1977) and maturity studies involving mea- 

 surements of ova diameters from ovaries of fish 

 collected off British Columbia (Pike 1951), the 

 spawning season is short, lasting from about 

 mid-June to mid-August. Based on available catch 

 records ( Williamson 1929 [in Pike 1951]; Pike 1951; 



^Richardson, S. L. 1977. Larval fishes in ocean waters off 

 Yaquina Bay Oregon: abundance, distribution, and seasonality 

 January 1971 to August 1972. Oreg. State Univ. Sea Grant Coll. 

 Prog. Publ. No. ORESU-T-77-003, 73 p. 



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