Fishery Bulletin/U S Dept of Commerce National

692 Abstract.-Fishing pressure on Genetic variation and phylogenetic deepwater oreasomatids has increased recently in Australian and New Zea relationships of seven oreo species land waters, and yet little is known aboutthese fish. Genetic variation and ITeleostei, OreosomatidaeJ inferred phylogenetic relationships amongAus tralianspecies was examined.Allozyme from allozyme analysis variation at 26 loci was examined in seven species: six from Australasia CAllocyttus niger, black oreo; A. ver Patricia S. Lowry ruCOBUS, warty orea; Neocyttus rhom boidalis, spiky oreo; Oreosoma atlanti Nicholas G. Elliott* cum, oxeye oreo; Pseudocyttus macu latus, smooth oreo; and a new species Gordon K. Yearsley Neocyttus sp., rough orea, infrequently captured with the smooth oreo and Robert D. Ward black orea) and one from the North At CSIRO Division of Fisheries lantic (N. helgae). Two phenetic trees GPO Box J 538, Hobart, Tasmania 700 I, Australia were constructed: an unweighted pair t:-lliaii d(.kir~~~: [email protected] group method with arithmetic averag ing (UPGMA) tree derived from Nei's unbiased genetic distances and a dis tance-Wagner tree derived from Rogers' distances. A maximum parsimony cla distic analysis, with loci as characters Oreos are laterally compressed, the smooth oreo (Pseudocyttus and alleles as unordered states, was deep-bodied fish with large heads maculatus Gilchrist, 1906) and the also performed. Outgroup species came from three related families: Acanthur and large eyes. They are found in black oreo (Allocyttus niger James idae, Berycidae, and Zeidae. deepwater (below 500 m) over the et al., 1988). In Australian waters Mean heterozygosity perlocus for the continental slopes of most temper oreos have been caughtlargely as a seven orea species was relatively high ate, and some tropical and subtropi bycatch of the deepwater fisheries for teleosts (11.8%), with O. atlanticum cal, regions. They appearto be more for blue grenadier (Macruronus having the lowest value (8.3%) and N. sp. having the highest value (18.1%). common in the Southern Hemi novaezelandiae (Hector, 1871» and Oreosoma atlanticum was the most di sphere, butthis mayreflect a greater orange roughy (Hoplostethus atlan vergent, with a mean genetic identity deepwater trawlingeffort in such re ticus Collett, 1889) and were gen (1) of 0.371. The two most closely re gions as New Zealand andAustralia. erally discarded. However, recent lated species-No rhomboidalis and N. The family Oreosomatidae (order drastic reductions in orange roughy helgae (I=0.973}-did not have any di agnostic allozyme loci, although the Zeiformes) contains four genera. In catch limits, the development of muscle protein patterns, after Coo a revision of oreos from the south new deepwater fishing grounds off massie blue staining, were distinctive. ern oceans, James et al. (1988) re southern Tasmania, and growing There was little evidence to supportthe ported that, although the family is market awareness have resulted in inclusion ofA. niger andA. verrucosus well defined and recognizable, its increasedtargetingofspecies aggre in the same genus; these two species had a genetic identity of 0.695. Allo generic relationships are less clear: gations and a rapid growth and re cyttus niger appeared to be more closely the genera Allocyttus, Neocyttus, tention of Australian catches of related to members of the genus ·Neo andOreosoma need redefining. The oreos (Lyle et aI., 1992). The re cyttus than to A. verrucosus. Phenetic fourth genus, Pseudocyttus, is well tained catch oforeo from the south analyses revealedonly minor differences defined and distinguishable. east fishery (the main deepwater in the Oreosomatidae grouping with re trawl fishery inAustralia) was less spectto thethree outgroups, whereascla Oreos are among the most abun distic analyses revealed the Zeidae asthe dant benthopelagic fishes on the than 100 metric tons (t) per annum most closely relatedfamily. continental slope of southern Aus before 1987, around 2,000 tin 1990 tralia, yet little is known of their and 1991, over 3,000 t in 1992, and biology, stock structure, or phylog over 1,000 t in 1993 and 1994 (Aus eny. In New Zealand waters, oreos tralian Fisheries Management Au havebeen fished commerciallysince thorityl). Actual catches are prob- the late 1970's. A peak catch of 26,500 metric tons (t) was taken in *Author to whom correspondence should be 1981-82; the fishery has since mod sent. erated to around 19,000 t per year 1 Australian Fisheries ManagementAuthor ity. 1995. Burns Centre, 28 National Manuscript accepted 6 June 1996. (Lyle et aI., 1992). The New Zealand Circuit, Forrest Act 2603. Australia. Fishery Bulletin 94:692-706 (1996). fishery comprises two main species: Unpubl. data. Lowry et al.: Phylogeny of Oreosomatidae 693 ably higher because some are not reported and oth Cyttus australis (Richardson, 1843) (silver dory), and ers discarded (Lyle et a!., 1992). The recorded ton the acanthurid Naso tuberosus Lacepede, 1802 nages of individual species are unreliable owing to (humphead unicornfish). confusion over species identification in the catch log Genetic variation present in the Australasian books. As inNew Zealand, the smooth andblackoreos oreosomatids and diagnostic allozyme loci for each dominate the Australian catch, whereas the spiky species are presented in this paper to assist in fu oreo (Neocyttus rhomboidalis Gilchrist, 1906) and the ture managementplans for the developing deepwater warty oreo (Allocyttus verrucosus (Gilchrist, 1906» fishery. The phylogenetic relationships ofpreviously are also important. A fifth species, the oxeye oreo known species, as well as a new species from Aus (Oreosoma atlanticum Cuvier, 1829), is commonly tralia and a species from the NorthAtlantic, are dis caught but discarded because of its small size and cussed in an effort to understand more fully the sys low commercial value. tematics ofthe family Oreosomatidae. This paper presents the results ofan allozyme sur vey of the five described Australasian species (j\llocyttus niger, A. verrucosus, Neocyttus rhomboi Materials and methods dalis, Oreosoma atlanticum, and Pseudocyttus maculatus) and a new species (the rough oreo, Samples of muscle and liver tissue were collected Neocyttus sp.,Yearsley and Last2) often captured with from seven oreosomatids fAllocyttus niger, Allocyttus A. niger and P. maculatus. Athird Neocyttus species, verrucosus, Neocyttus sp. (voucher specimen: CSIRO N. helgae (Holt and Byrne, 1908), from the North H2865.01), Neocyttus helgae, Neocyttus rhomboidalis, Atlantic, was also examined. Oreosoma atlanticum and Pseudocyttus maculatus), Oreosomatids not included in this study are the andfrom the three outgroup species (Beryx splendens, North Pacific Allocyttus folletti Myers, 1960, the Cyttus australis, and Naso tuberosus). Sample de southern Atlantic and Indian Ocean Allocyttus tails and species abbreviations are given in Table 1. guineensis Trunov and Kukuev in Trunov, 1982, and Whole fish were frozen after capture and trans the Indian OceanNeocyttus acanthorhyncus (Regan, ported frozen to the laboratory, where tissues were 1908). Another member of the family, the Southern dissected and held at -SO°C. Small pieces of tissue Ocean Pseudocyttus nemotoi (Abe, 1957), was re were placed in 1.5-mLmicrocentrifuge tubes, homog cently resurrected by Miller (1993). enized manually with a few drops ofdistilled water, The intrarelationships of zeiforms have not been and spun at 11,000 rpmin a microcentrifuge for 2 min discussed in the literature; thus outgroup selection utes. The supernatant was used for electrophoresis. for this phylogenetic studyis difficult. Many authors Allozyme variation was examined with three gel consider the beryciforms to be more primitive than systems: gel system A-Helena Titan III cellulose the zeiforms but closely related to them (e.g. Green acetate plates run at 200 V with a Tris-glycine buffer wood eta!., 1966). Zehren (1979) found the Berycidae (0.020 M tris and 0.192 M glycine, Hebert and to be more primitive than the remaining beryciform Beaton3); gel system B-Helena Titan III cellulose families and, thus, a berycid may be a suitable acetate plates run at 150 V with a Tris-citrate buffer outgroup. However, Rosen (1984) dramatically (0.075 M tris and 0.025 M citric acid, pH 7.0); gel changed the placement of the zeiforms, including system C-8% Connaught starch gels with a histi them in the order Tetraodontiformes, with the dine/citrate buffer (gel buffer: 0.005 M histidine HCI, Caproidae as the sister group to all other tetra pH 7.0; electrode buffer: 0.41 M trisodium citrate, odontiforms (the caproids' placement within the pH 7.0). Standard staining procedures were followed Zeiformes was questioned by others [Tighe and (Richardson et a!., 1986; Hebert and Beaton3). Keene, 1984]). A caproid may therefore be a suitable In all, 19 enzymes, representing 27 loci, were ex outgroup. Furthermore, Rosen placed the zeids im amined (Table 2) and allele frequencies determined mediately before the oreosomatids in his new divi (Table 3). However, the locus GPI-A*was notincluded sion Zeomorphi. He used "acanthurids plus chaeto in the phylogenetic analyses because of poor resolu dontids" to establish character polarities. Conse tion in three species fA. niger, N. sp., and P. macu quently, a zeid or an acanthurid are also possible latus). Loci and alleles are designated bythe nomen outgroups. In the absence ofcaproid specimens,

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