564 



ONTOGENY AND SYSTEMATICS OF FISHES-AHLSTROM SYMPOSIUM 



Greenwood et al. ( 1 966) in placing Harpagiferinae as a subfam- 

 ily of Nototheniidae (Table 140). 



Development 



The first work on the early life history of these fishes was 

 undertaken with material collected on the polar expeditions of 

 the early 20th century. Regan (1916) illustrated larvae of seven 

 notothenioid species. Additional early life history data were 

 sparse until the Antarctic expeditions of the second half of the 

 century. In the last 30 years efforts have been directed toward 

 understanding the biology, ecology, population dynamics, and 

 physiological adaptations of these fish. In these investigations 

 some early life history data have been acquired. Larvae of 36 

 species have been described (Table 140). The most comprehen- 

 sive summaries are the key in North and White (1982), the 

 papers of Yefremenko (1979b, c) and the atlas of Efremenko 

 (1983a).' No early life history data are available for the family 

 Bovichthyidae except for a brief description of the behavior and 

 an illustration of a 25 mm prejuvenile of Bovichthys variegatus 

 (Robertson and Mito, 1979). 



Eggs 



Eggs of four notothenioid families have been described in- 

 cluding some known only from studies of ovaries (Table 141). 

 Eggs are moderate to large (1.2-4.5 mm diameter) with large 

 yolks, no oil globules, and small perivitelline spaces (Marshall, 

 1953; Andriashev, 1965; Dearborn, 1965). In one species, No- 

 tothenia ( Trematomus) hernacchii. eggs are bright yellow to deep 

 brown. Most species are demersal spawners; nesting behavior 

 has been observed in N. hernacchii (Moreno, 1980) and Har- 

 pagifer hispinis (Daniels, 1978). However, Notothenia micro- 

 lepidola eggs have been reported from plankton collections 

 (Robertson, 1975a). The demersal eggs are sticky, clinging to 

 substrate or algae. One species, N. neglecta. reared in the lab- 

 oratory from artificially fertilized eggs, has an incubation time 

 of 103-150 days and hatches with a well-developed, heavily 

 pigmented body, black eyes, and a large yolk sac (White et al., 

 1982). Daniels (1978) reports an incubation time of 14 to 18 

 weeks for H. hispinis. 



Larvae 



Morphology— The described larvae of 36 species display some 

 morphological similarity (snout-anus length), and some diver- 

 sity (snout length and body shape). Preflexion larvae, ca. 6-18 

 mm SL, are elongate with large pectoral fins and moderate to 

 wide finfolds. Channichthyid larvae have well developed pelvic 

 fins at this stage and more elongate snouts than larvae of other 

 notothenioids. Some species have large yolk sacs which persist 

 after notochord flexion has begun. Preanal lengths range from 

 slightly under to slightly over 50% of body length. 



Dunng flexion and postflexion stages most larvae maintain 

 their elongate shape (Fig. 301). However the larvae of the har- 

 pagiferid genera Artedidraco and Pogonophryne become very 

 robust (North and White, 1982; Efremenko, 1983a). Notochord 

 flexion occurs between 9 and 42 mm with larval Harpagiferidae 

 and Nototheniidae flexing at the shortest lengths, Channichthyi- 

 dae at the longest, and Bathydraconidae at intermediate lengths 

 (Table 141). Size at transformation to the juvenile stage also 

 spans a wide range with Harpagifer hispinis settling at 18.3 mm 



' Efremenko and Yefremenko are alternative transliterations of the 

 name of the same author. 



(Everson, 1 968) and pelagic larvae of other species reaching 24- 

 60 mm (de Ciechomski and Weiss, 1976; North and White, 

 1982; Yefremenko, 1979b, c). 



Larvae of all species develop pelvic fins. Channichthyid larvae 

 retain their elongate snouts and develop teeth and preopercular 

 and rostral spines not reported for other notothenioids (Fig. 

 301). 



Pigmentation. — Pi%menx patterns of all known larvae are highly 

 specific and are useful identification criteria. The amount and 

 location of pigment varies within families and the amount usu- 

 ally increases with development. A few species have general 

 body pigment, but most exhibit patterns in one or more of the 

 following areas: dorsal body margin, ventral body margin, body 

 midline, peritoneum, gut, and along the myosepta. The occipital 

 and parietal areas typically are pigmented; many species have 

 snout, opercular, and jaw pigment as well. The paired fins are 

 usually pigmented. Pigment is found at the base of the caudal 

 fin in most species, associated with the posterior margin of the 

 hypural elements or the bases of the caudal rays. 



Meristics. — Meristics are from counts given for adults by Regan 

 (1913d, 1916), Norman (1937, 1938a), Nybelin (1947, 1951), 

 Andriashev (1959), and DeWitt (1970) (Table 142). Vertebral 

 counts are especially useful diagnostic features within and be- 

 tween families. The dorsal, anal, pectoral, and vertebral counts 

 have been the most significant characters linking larvae to adults 

 (Yefremenko, 1979b, c). The sequence of fin formation is the 

 same in Nototheniidae, Harpagiferidae, and Bathydraconidae 

 with pectoral and caudal fins forming first, followed by pelvics, 

 with dorsal and anal last to ossify. In Channichthyidae the pel- 

 vics are precocious and are present in yolk-sac larvae. 



Relationships 



Knowledge of the early life history of Notothenioidea has not 

 contributed to understanding relationships between Blennioidei 

 and other perciform suborders, but does ofler some clues to 

 relationships within the suborder. The lengthy ovarian egg de- 

 velopment (Dearborn, 1965; Everson, 1970) is probably related 

 to the cold environment. In other aspects of spawning, i.e., 

 nesting behavior, long incubation time, and laying of demersal 

 adhesive eggs, this infraorder resembles other cold-water blen- 

 nioids. The well developed state of newly hatched larvae and 

 the sequence of fin development as well as the general lack of 

 specialized larval structures are also blennioid features. Further 

 study of developmental characters, such as the sequence of os- 

 sification, might contribute to better understanding of the re- 

 lationships among the Blennioidei. Superficial morphological 

 and meristic resemblances exist among notothenioid larvae and 

 those of other blennioid species, for example, the notothenioid 

 Patagonotothen larscni (Fig. 301), the trachinoid Trichodon 

 trichodon (see Trachinoidea, this volume) and the blennioid 

 Heterostichus rostratus (see Blennioidea, this volume). As re- 

 lationships among the blennioids become better known, their 

 relationship with other perciforms might become clearer. 



(E.G.S.) National Marine Fisheries Service, Southwest 

 Fisheries Center, PO Box 271, La Jolla, California 

 92038; (W.W.) Marine Ecological Consultants, 531 

 Encinitas Boulevard, Encinitas, California 92024; 

 (A. CM.) National Marine Fisheries Service, North- 

 west AND Alaska Fisheries Center, 2725 Montlake 

 Boulevard East, Seattle, Washington 981 12. 



