G. Kelling (editors), Submarine canyon, fan and trench sedi- 

 mentation, p. 65-70. Hutchinson and Ross, Dowdon, U.K. 



Gary D. Grossman 



Michael J. Harris 



Joseph E. Hightower 



School of Forest Resources 

 University of Georgia 

 Athens, GA S0602 



THE DEVELOPMENT AND OCCURRENCE OF 



LARVAE OF THE LONGFIN IRISH LORD, 



HEMILEPIDOTUS ZAPUS (COTTIDAE). 



The subfamily Hemilepidotinae, endemic to the 

 North Pacific Ocean, is one of the more generalized 

 subfamilies within the Cottidae (Peden 1978). 

 According to Peden (1978), the subfamily is compos- 

 ed of three subgenera: 1) Calycilepidottcs which in- 

 cludes Hemilepidottcs spinostts; 2) Hemilepidotus 

 which includes H. hemilepidotus, H. jordani, H. 

 zapus, and H. gilberti; and 3) Melletes which includes 

 H. papilio. The early life histories of most species are 

 inadequately known and separation of larvae in mix- 

 ed samples is difficult. Gorbunova (1964) described a 

 number of larval series which she labeled H. 

 hemilepidotus, H. gilberti, H. gilberti zapus, H. jor- 

 dani, and H. papilio,^ but these descriptions are in- 

 complete as well as incorrect for several species 

 (Peden 1978; Richardson and Washington 1980). 

 Hattori (1964) described a series of//, gilberti larvae 

 (7.1-32.5 mm), and Peden (1978) illustrated postlar- 

 vae (> 18 mm) of //. hemilepidotus, H. spinosus, H. 

 zapras, and H. jordani. Richardson and Washington 

 (1980) described larvae of H. hemilepidotus and H. 

 spinosus. We here provide the first complete descrip- 

 tion of//, zapus larvae, and include comments on lar- 

 val occurrence in the eastern Bering Sea. This work 

 supplements and clarifies the work of previous 

 researchers by providing diagnostic characters 

 useful in distinguishing the species. 



MATERIALS AND METHODS 



Specimens of//, zapus used in this study were col- 

 lected during ichthyoplankton surveys conducted in 

 the Bering Sea by the Northwest and Alaska Fisher- 

 ies Center between 1977 and 1980. Morphological 



measurements were made on 57 unstained larvae 

 (6.7-22.0 mm SL) following Matarese et al. (1981), 

 except depth at caudal peduncle which was measured 

 at the point of least depth. Measurements were 

 grouped by 1 mm SL intervals, and the means of the 

 measurements within each interval were plotted as 

 percentage of the mean of standard lengths or head 

 lengths within the interval (Kendall and Vinter 

 1984). A computer-generated best nonparametric 

 curve, based on all data points, was drawn to illus- 

 trate relative growth trends. Counts of meristic 

 structures were made on 18 specimens differentially 

 stained according to Dingerkus and Uhler (1977) 

 following procedures outlined in Matarese et al. 

 (1981). Terminology of head spination generally 

 follows Richardson and Laroche (1979) and Richard- 

 son and Washington (1980). Illustrations were made 

 by the junior author with a camera lucida, and all 

 specimens were preserved in either 3% Forma- 

 lin^ buffered with sodium borate or 100% glycer- 

 in. 



Identification of 

 Hemilepidotus zapus 



We have routinely collected three types of Hemi- 

 lepidotinae larvae during ichthyoplankton surveys in 

 the eastern Bering Sea (1977-80). According to 

 Peden (1978), four species of adults occur in this 

 area: Hemilepidotus hemilepidotus, H. jordani, H. 

 zapus, and H. papilio. Although preflexion larvae of 

 H. hemilepidotus and H. jordani cannot presently be 

 separated, we can separate the two species at noto- 

 chord flexion according to differences in external 

 pigment along the posterior body. Hemilepidotus 

 hemilepidotus larvae develop pigment above the 

 notochord along the posterior body earlier and in 

 greater density than larvae of//, jordani (Fig. lA, 

 B). Initially, the third series of larvae (< 17.0 mm SL) 

 was misidentified as //. papilio (see Waldron and 

 Vinter^) based on the presence of urostyle pigment 

 (Gorbunova 1964). With the acquisition of larger 

 specimens, > 17.0 mm SL, the complete series was 

 later identified as H. zapus based on a set of charac- 

 ters taken in part from Peden (1978) (Table 1). Gor- 

 bunova's (1964) specimen attributed to H. zapus 

 lacks pigment on the urostyle; of her two illustra- 

 tions of//, papilio (footnote 1) only the 10.7 mm SL 



^Hemilepidotus papilio (= Melletes papilio from Gorbunova 

 (1964)). 



^References to trade names do not imply endorsement by the Na- 

 tional Marine Fisheries Service, NOAA. 



^Waldron, K. D., and B. M. Vinter. 1978. Ichthyoplankton of 

 the eastern Bering Sea. Unpubl. manuscr., 77 p. Northwest and 

 Alaska Fisheries Center, National Marine Fisheries Service, 

 NOAA, 2725 Montlake Boulevard E., Seattle, WA 98112. 



FISHERY BULLETIN: VOL. 83, NO. 3, 1985 



447 



