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Fishery Bulletin 92(4), 1994 



life history of fishes for a region. 



The taxonomic diversity of Indo-Pacific coral reefs 

 and Japanese waters is much greater than that found 

 at higher latitudes, resulting in lower proportions of 

 species with identified larvae in these and other low- 

 latitude regions. Speciose perciform families present 

 at lower latitudes contribute to the difficulty of iden- 

 tifying larvae in these regions. In other regions, taxo- 

 nomic groups that have undergone extensive radia- 

 tion complicate identification of larvae. For example, 

 about 70 species ofSebastes are present in the North- 

 east Pacific and they cannot be identified routinely 

 in plankton samples (Matarese et al., 1989). The lar- 

 vae of some closely related taxa in commercially im- 

 portant groups in other regions have proven very 

 difficult to identify (e.g. tunas [scombrids], some her- 

 rings [clupeids], and North Atlantic cods [gadids]). 



Conclusions 



In spite of the relatively large proportions of fishes 

 in some regions for which some early life history 

 stages have been illustrated, identification problems 

 still limit the usefulness of ichthyoplankton studies. 

 For example, in the Northeast Pacific where identi- 

 fication is possible only to family or genus for sev- 

 eral groups (e.g. Sebastes spp., cottids, agonids, and 

 stichaeids), more descriptive work remains to be 

 done. It is ironic that some groups containing some 

 of the world's most important fisheries (e.g. tunas, 

 cods, and herrings) also pose some of the more diffi- 

 cult problems regarding egg and larval identification. 

 Research involving field studies offish eggs and lar- 

 vae in several parts of the world is now concentrat- 

 ing on recruitment dynamics of commercially impor- 

 tant species, whose early stages are well described. 

 Two of the goals of the Ahlstrom Symposium held 

 in 1983 were to accumulate information on fish de- 

 velopment by taxa, and thus stimulate additional 

 research on poorly known groups, and to highlight 

 the potential usefulness of developmental informa- 

 tion in systematic studies. Since the volume based 

 on the Ahlstrom Symposium was published (Moser 

 et al., 1984), many important original descriptive pa- 

 pers have appeared (e.g. Ditty, 1989; Fahay, 1992), 

 but it does not seem that there has been a signifi- 

 cant increase in the number of larvae known. Rather 

 than an increase in original descriptions, the late 

 1980s saw the publication of several regional guides 

 to fish early life history (see Table 2). While some 

 recent systematic studies have considered larval as 

 well as adult characters (e.g. Cohen, 1989; Baldwin, 

 1990; Baldwin and Johnson, 1993; Strauss, 1993), 

 there are still unresolved theoretical problems with 



this approach. Some ichthyologists still do not want 

 to deal with those "unidentifiable pinheads" (Winter- 

 bottom, 1986), and rigorous analysis of developmen- 

 tal, in addition to adult, characters can be a daunt- 

 ing task. According to Johnson (1993): "Almost 10 

 years after its [i.e. Moser et al., 1984] publication 

 the historical separation between studies of early life 

 history stages and 'mainstream' systematic ichth- 

 yology appears only slightly diminished. Most com- 

 parative osteological and phylogenetic studies of 

 fishes do not incorporate development and thus ig- 

 nore the potential for additional suites of characters 

 and for testing homology." 



A combination of rearing studies and developing 

 series from plankton samples as well as more inno- 

 vative techniques such as biochemical genetics (Seeb 

 and Kendall, 1991) will be required to fill the gaps 

 in our knowledge on the identification of early de- 

 velopmental stages of marine fishes. Although the 

 value of egg and larval studies are recognized in fish- 

 eries science, their usefulness will probably remain 

 limited without the continued efforts of scientists who 

 often describe early life stages as ancillary but enjoy- 

 able endeavors. 



Acknowledgments 



Deborah Blood (AFSC) provided helpful suggestions 

 and ideas that were incorporated into early drafts of 

 the manuscript. Morgan Busby (AFSC) assisted with 

 gathering and interpreting the literature we used. 

 Also, several of our colleagues encouraged us in this 

 exercise and provided helpful reviews of earlier ver- 

 sions of the manuscript: Bill Richards, Southeast 

 Fisheries Science Center, Miami, FL; Geoff Moser, 

 Southwest Fisheries Science Center, La Jolla, CA; 

 and Mike Fahay, Northeast Fisheries Science Cen- 

 ter, Sandy Hook, NJ, who actually commented on two 

 versions of the manuscript. 



Literature cited 



Aboussouan, A. 



1989. L'identification des larvae de poissons de la 

 mer Mediterranee. Cybium 13:259-262. 

 Agassiz, A. 



1882. On the young stages of some osseous fishes. 

 Proc. Am. Acad. Arts Sci. 16 (Pt. 3):271-303. 

 Ahlstrom, E. H., and O. P. Ball. 



1954. Description of eggs and larvae of jack mack- 

 erel {Trachurus symmetricus) and distribution and 

 abundance of larvae in 1950 and 1951. U.S. Fish 

 Wildl. Serv., Fish. Bull. 56:209-245. 



