FISHERY BULLETIN: VOL. 85, NO. 1 



phy and Taylor MS in review^; larval and juvenile 

 S. ocellatus, M. M. Leiby^; deep-sea benthic fishes, 

 K. J. Sulak«). 



Species Composition, Zoogeographic 

 Affinities, Hydrographic Influence 



Relatively few accounts have been published on 

 Gulf of Mexico myctophids. Rass (1971) examined 

 material from 5 years of deep otter travel collections 

 and reported 20 species. Bekker et al. (1975) iden- 

 tified 31 species from 19 stations in the southwest- 

 ern Gulf, while Backus et al. (1977) collected 38 

 species from 7 midwater trawl stations extending 

 from the north central to the southwestern Gulf. 

 Nafpaktitis et al. (1977) recorded 52 species based 

 on a variety of collections and earlier accounts from 

 throughout the Gulf. Murdy et al. (1983) listed 39 

 species of myctophids taken from 35 Isaacs-Kidd 

 Midwater Trawl stations also located throughout the 

 Gulf. Most recently, Hopkins and Lancraft (1984) 

 reported 34 species from 28 oblique hauls taken with 

 an open net between and 1,000 m at Standard Sta- 

 tion. With the exception of Backus et al. (1977) and 

 Nafpaktitis et al. (1977), these accounts are mainly 

 annotated species lists. 



Of these earlier studies, only Bekker et al. (1975) 

 and Nafpaktitis et al. (1977) reported myctophid 

 species not found in the present study. Bekker et 

 al. captured one specimen each of Lampadena ano- 

 mala and Lampanyctus festivus. Nafpaktitis et al. 

 listed five species {Diaphus adenormts, D. anderseni, 

 D. metopoclampus, D. minax, Lepidophanes gaussi) 

 from the Gulf which we have not collected. The 

 records of D. anderseni and D. minax, each based 

 on a single specimen from our University of South 

 Florida collections, were found to be misidentifica- 

 tions of D. brachycephalus and D. perspicillatus, 

 respectively. Of the other five species, D. adenomus 

 appears to be epibenthic (Clarke 1973; Hulley 1981) 

 and as such cannot be considered part of the meso- 

 pelagic myctophic assemblage. The captures of Lam- 

 padena anomala, Lampanyctus festivus, and D. 

 metopoclampus were well to the south and west of 

 our study areas. Because of differences in circula- 



^Murphy, M. D., and R. G. Taylor. Reproduction, growth and 

 mortality of red drum, Sciaenops ocellatus in Florida. Manuscr. 

 in prep. Department of Natural Resources, Bureau of Marine 

 Research, 100 8th Avenue S.E., St. Petersburg, FL 33701. 



'M. M. Leiby, Florida Department of Natural Resources, Bureau 

 of Marine Research, 100 8th Avenue S.E., St. Petersburg, FL 

 33701, pers. commun. January 1986. 



*K. J. Sulak, Atlantic Reference Centre, Huntsman Marine 

 Laboratory, St. Andrews, New Brunswick EOG 2X0, Canada, pers. 

 commun. June 1986. 



tion patterns of western and eastern Gulf waters, 

 these species may never occur as far east as our 

 sampling areas. Thus, the only species that we can- 

 not reconcile is Lepidophanes gaussi, which was 

 reported from the eastern Gulf by Nafpaktitis et al. 

 (1977), although at best this species appears to be 

 an exceedingly rare visitor. 



Despite these records, we feel that with the data 

 from the present study, the eastern Gulf of Mexico 

 myctophid fauna has been defined. Of our 49 species, 

 42 were taken on the first three cruises and all 49 

 were collected by 1976. Despite an additional 20 

 cruises with approximately 600 mesopelagic trawl 

 samples and over 8 x lO*' m^ water filtered, we 

 have not added a single new species. We also con- 

 clude that all 49 species, including the 6 species 

 listed as rare, are typical components of the eastern 

 Gulf myctophid assemblage during the warm 

 months. In other studies of myctophid assemblages 

 (Clarke 1973; Karnella 1983), the term "rare" is 

 used to designate species whose centers of geo- 

 graphic distribution lie outside the study area but 

 which may occasionally be captured as strays, a 

 definition which does not apply in the present study. 

 With the exception of Hygophum hygomii, whose 

 low numbers are attributed to geographic exclusion 

 by its congener, H. benoiti (Nafpaktitis et al. 1977), 

 the rare species in the eastern Gulf are everywhere 

 rare or extremely uncommon. Data from the upper 

 1,000 m collected in the eastern Gulf since 1977 

 show all but the Taaningichthys species, which may 

 occur below our normal fishing depth ranges, to be 

 persistent low abundance members of the myctophid 

 assemblage. Additional evidence of this is the cap- 

 ture of the larvae of Symbolophorus rufinus and 

 Notoscopelus caudispinosus in the eastern Gulf 

 (Houde et al. 1979; W. J. Conley^). 



The number of myctophid species associated with 

 a particular distribution pattern as defined by 

 Backus et al. (1977) are listed in Table 8. Three of 

 the 49 species captured in the Gulf (Diaphus taa- 

 ningi, Taxiningichthys bathyphilus, T. paurolychnus) 

 are omitted because they have indeterminate 

 geographic distributions. Diaphus taaningi is a 

 pseudooceanic species, associated primarily with 

 land, while the two Taaningichthys species are 

 bathypelagic and do not appear to conform to 

 shallower mesopelagic zoogeographic patterns. 



Representatives of five of the nine Atlantic distri- 

 bution patterns established by Backus et al. (1977) 



^W. J. Conley, University of South Florida, Department of 

 Marine Science, 140 7th Avenue S.E., St. Petersburg, FL 33701, 

 pers. commun. September 1985. 



94 



