3 



V = total volume of water (m ) strained 



during the haul 



V = R • a • p 



where R = total number of revolutions of the current 

 meter during the haul 



2 

 a = area (m ) of the mouth of the net 



p = length of column of water (m) needed to 

 produce one revolution of the current 

 meter. 



Tow depth, volume of water strained, and standard haul factor are 

 listed in Table 1 for each tow taken during 1975. Detailed 

 descriptions of factors involved in calculating these values are 

 presented in Ahlstrom (1948), Kramer et al. (1972), and Smith and 

 Richardson (1977) . 



IDENTIFICATION 



Identification of ichthyoplankton species beyond those 

 separated during the sorting process was carried out by a 

 separate group of specialists. Ontogenetic stages of fishes are 

 inherently difficult to identify and this is further complicated 

 by the large number and diversity of species which contribute to 

 the ichthyoplankton of the California Current region. Most 

 identifications were accomplished by establishing ontogenetic 

 series on the basis of morphology, meristics, and pigmentation 

 and then identifying these series by relating them to known 

 metamorphic, juvenile, or adult stages with overlapping features 

 (Powles and Markle, 1984) . A total of 148 taxa was identified 

 for 1981, with 93 taken to species, 27 to genus, 24 to family, 

 and 4 to order or suborder. In the decade of the 1970 's some 

 taxa were identified for the first time. These included larvae 

 of the bathylagid Bathylagus longirostris , the gonostomatids 

 Danaphos oculatus and Valencienellus stellatus , the myctophid 

 Bolinichthys spp . , and the trichiurid Lepidopus xantusi . Larvae 

 in the families Scopelarchidae and Nomeidae were identified to 

 genus or species. Five species of rockfish in the Sebastes group 

 were also identified: S. aurora, S. j ordani , S. levis, S. 

 macdonaldi , and S. paucispinis. In 1981, four species of 

 Sciaenidae were identified for the first time: Cheilotrema 

 saturnum , Genyonemus lineatus , Roncador stearnsii , and Seriphus 

 politus . 



The task of producing a reliable and equitable 

 ichthyoplankton data base required extensive procedures to 

 verify, correct, and edit the original identifications. The 

 primary data source was the original identification sheets (see 

 Kramer et al., 1972, for examples); however, a critical resource 

 used in all phases of this process was the CalCOFI 



