Pronounced genetic population structure in a potentially vagile fish species (Pristipomoides multidens, Teleostei; Perciformes; Lutjanidae) from the East Indies triangle

The East Indies triangle, bordered by the Phillipines, Malay Peninsula and New Guinea, has a high level of tropical marine species biodiversity. Pristipomoides multidens is a large, long-lived, fecund snapper species that is distributed throughout the East Indies and Indo-Pacific. Samples were analysed from central and eastern Indonesia and northern Australia to test for genetic discontinuities in population structure. Fish (n = 377) were collected from the Indonesian islands of Bali, Sumbawa, Flores, West Timor, Tanimbar and Tual along with 131 fish from two northern Australian locations (Arafura and Timor Seas) from a previous study. Genetic variation in the control region of the mitochondrial genome was assayed using restriction fragment length polymorphism and direct sequencing. Haplotype diversity was high (0.67-0.82), as was intraspecific sequence divergence (range 0-5.8%). FST between pairs of populations ranged from 0 to 0.2753. Genetic subdivision was apparent on a small spatial scale; FST was 0.16 over 191 km (Bali/Sumbawa) and 0.17 over 491 km (Bali/Flores). Constraints to dispersal that contribute to, and maintain, the observed degree of genetic subdivision are experienced presumably by all life history stages of this tropical marine finfish. The constraints may include (1) little or no movement of eggs or larvae, (2) little or no home range or migratory movement of adults and (3) loss of larval cohorts due to transport of larvae away from suitable habitat by prevailing currents

Population genetic evidence for the east–west division of the narrow-barred Spanish mackerel (Scomberomorus commerson, Perciformes: Teleostei) along Wallace’s Line

Mitochondrial DNA D-loop (control) region (426-bp) was used to infer the genetic structure of Spanish mackerel (Scomberomorus commerson) from populations in Southeast Asia (Brunei, East and West Malaysia, Philippines, Thailand, Singapore, and China) and northern Australia (including western Timor). An east–west division along Wallace’s Line was strongly supported by a significant AMOVA, with 43% of the total sequence variation partitioned among groups of populations. Phylogenetic and network analyses supported two clades: clade A and clade B. Members of clade A were found in Southeast Asia and northern Australia, but not in locations to the west (Gulf of Thailand) or north (China). Clade B was found exclusively in Southeast Asia. Genetic division along Wallace’s Line suggests that co-management of S. commerson populations for future sustainability may not be necessary between Southeast Asian nations and Australia, however all countries should share the task of management of the species in Southeast Asia equally. More detailed genetic studies of S. commerson populations in the region are warranted.

The complete validated mitochondrial genome of the silver gemfish Rexea solandri (Cuvier, 1832) (Perciformes, Gempylidae)

The silver gemfish Rexea solandri is an important economic resource but vulnerable to overfishing in Australian waters. The complete mitochondrial genome sequence is described from 1.6 million reads obtained via next generation sequencing. The total length of the mitogenome is 16,350 bp comprising 2 rRNA, 13 protein-coding genes, 22 tRNA and 2 non-coding regions. The mitogenome sequence was validated against sequences of PCR fragments and BLAST queries of Genbank. Gene order was equivalent to that found in marine fishes.

Age and growth of Mugil cephalus (Linnaeus, 1758) (Perciformes: Mugilidae) in Bonny Estuary

The age and growth of Mugil cephalus was investigated in Bonny Estuary, Nigeria, from January, 1995 to December, 1996. Length-weight relationships were isometric with length exponents of 2.84 (males), 2.90 (females) and 2.88 (overall). Modal length at age were 12.0cm, 20.9cm, 25.0cm, 28.4cm and 30.2cm TL for ages 0+, 1+, 2+, 3+ and 4+ respectively. Corresponding total weights were 20.01g, 78.93g, 173.12g, 217.61g and 247.50g, respectively. Asymptotic length (Lo) was estimated 33.2cm TL, asymptotic weight (W sub(o)) was 484g, growth coefficient K=0.55847 super(-1) and hypothetical age at zero length To = 0.152yr. Longevity, Tmax, was 5.0yr, length and weight growth performance indices were Q super(1)=2.79 and Q = 1.44, respectively. Total mortality, natural mortality and fishing mortality were z = 1.02yr super(-1), M=0.607yr super(-1) and F=O. 3129yr super(-1), respectively. The exploitation ratio E was 0.4048 and exploitation rate U = 0.2302yr super(-1)

Larval development of estuary perch (Macquaria colonorum) and Australian bass (M. novemaculeata) (Perciformes: Percichthyidae), and comments on their life history

Morphological development of the larvae and small juveniles of estuary perch (Macquaria colonorum) (17 specimens, 4.8−13.5 mm body length) and Australian bass (M. novemaculeata) (38 specimens, 3.3−14.1 mm) (Family Percichthyidae) is described from channel-net and beach-seine collections of both species, and from reared larvae of M. novemaculeata. The larvae of both are characterized by having 24−25 myomeres, a large triangular gut (54−67% of BL) in postflexion larvae, small spines on the preopercle and interopercle, a smooth supraocular ridge, a small to moderate gap between the anus and the origin of the anal fin, and distinctive pigment patterns. The two species can be distinguished most easily by the different distribution of their melanophores. The adults spawn in estuaries and larvae are presumed to remain in estuaries before migrating to adult freshwater habitat. However, larvae of both species were collected as they entered a central New South Wales estuary from the ocean on flood tides; such transport may have consequences for the dispersal of larvae among estuaries. Larval morphology and published genetic evidence supports a reconsideration of the generic arrangement of the four species currently placed in the genus Macquaria.

Guide to the identification of larval and early juvenile pricklebacks (Perciformes: Zoarcoidei: Stichaeidae) in the northeastern Pacific Ocean and Bering Sea

Stichaeidae, commonly referred to as pricklebacks, are intertidal and subtidal fishes primarily of the North Pacific Ocean. Broad distribution in relatively inaccessible and undersampled habitats has contributed to a general lack of information about this family. In this study, descriptions of early life history stages are presented for 25 species representing 18 genera of stichaeid fishes from the northeastern Pacific Ocean, Bering Sea, and Arctic Ocean Basin. Six of these species also occur in the North Atlantic Ocean. Larval stages of 16 species are described for the first time. Additional information or illustrations intended to augment previous descriptions are provided for nine species. For most taxa, we present adult and larval distributions, descriptions of morphometric, meristic, and pigmentation characters, and species comparisons, and we provide illustrations for preflexion through postflexion or transformation stages. New counts of meristic features are reported for several species.

Larvae of Dactylopsaron dimorphicum (Perciformes: Percophidae) from oceanic islands in the southeast Pacific

Percophids are a family of small marine benthic fishes common over soft bottoms from inshore to the outer slopes in tropical to temperate regions of the Atlantic and in the Indo-West and southeast Pacific (Reader and Neira, 1998; Okiyama, 2000). Five species belonging to four genera have been recorded around the Salas y Gómez Ridge in the southeast Pacific, all of which are endemic to the area except for Chrionema chryseres, a species which also occurs off the Hawaiian Islands and Japan (Parin, 1985, 1990; Parin et al., 1997). Of these five species, larval stages have been described only for Osopsaron karlik and Chrionema pallidum (Belyanina 1989, 1990).

Length-weight relationship in Nandus nandus (Hamilton) (Perciformes-Teleostei)

Length-weight relationship of the freshwater fish of Pamba River, Nandus nandus (Ham) has been worked out. The results showed that the slope values and elevations were not significant and hence a combined regression equation has been calculated for both the sexes (Log W=2.4130 Log L -0.3306). The’t’ test analyses were conducted and found that the growth departs significantly from the isometric growth. Thus the formula W=aL super(n) has to be applied in calculating the length-weight relationship of this species.

湖南省境内洞庭鳜(Tungtingichthys,鲈形目Perciformes)的重新观察

对秀丽洞庭鳜作了较详细的描述，在骨骼学特征和变异范围方面作了较多的补充。指出秀丽洞庭级和下湾铺洞庭鳜在背鳍前骨式、林的形状和尾鳍前短鳍条数目等特征存在差异。补充了洞庭鳜的属征，并认为始新世化石低等鲈形目鱼类中北半球的洞庭鳜、Amphiperca、Priscacara之间的关系比它们和南半球的Percichthys的关系更接近。

Non-monophyly of fish in the Sinipercidae (Perciformes) as inferred from cytochrome b gene

The sinipercids represent a group of 12 species of freshwater percoid fish, including nine in Siniperca and three species in Coreoperca. Despite several classification attempts and a preliminary molecular phylogeny, the phylogenetic relationships and systematic position of sinipercids remained still unsolved. The complete cytochrome b gene sequences from nine sinipercid species four non-sinipercid fish species were cloned, and a total of 12 cyt b sequences from 10 species of sinipercids and 11 cyt b sequences from 10 species of non-sinipercid fish also in Perciformes were included in the phylogenetic analysis. As expected, the two genera Siniperca and Coreoperca within sinipercids are recovered as monophyletic. However, nine species representing Moronidae, Serranidae, Centropomidae, Acropomatidae, Emmelichtyidae, Siganidae and Centrarchidae included in the present study are all nested between Coreoperca and Siniperca, which provides marked evidence for a non-monophyly of sinipercid fishes. Coreoperca appears to be closest to Centrachus representing the family Centrarchidae. Coreoperca whiteheadi and C. herzi are sibling species, which together are closely related to C. kawamebari. In the Siniperca, the node between S. roulei and the remaining species is the most ancestral, followed by that of S. fortis. S. chuatsi and S. kneri are sibling species, sister to S. obscura. However, the sinipercids do not seem to have a very clear phylogenetic history, for different methods of phylogenetic reconstruction result in different tree topologies, and the only conclusive result in favor of a paraphyletic origin of the two sinipercid genera is the parametric bootstrap test. The paraphyly of Sinipercidae may suggest that the "synapomorphs" such as cycloid scales, upon which this family is based, were independently derived at least twice within sinipercid fishes, and further study should be carried out to include the other two Siniperca species and to incorporate other genes.

Histological and cytological studies on the developing thymus of mandarin fish Siniperca chuatsi (Perciformes : Teleostei)

The thymus of the mandarin fish, Siniperca chuatsi, was examined by light and transmission electron microscopy to understand its formation and cellular composition. Larvae of the mandarin fish were collected and sectioned from 1 to 35 days post-hatching (dph). On dph 7 the thymus was packed with lymphocytes. From 12 dph onward, mucous cells were observed on the epithelial layer; from 23 dph, three zones could be differentiated in the thymic parenchyma. The thymus was connected with the extension of the third, fourth and fifth branchial pouches throughout early development, remaining in a superficial position in the adult S. chuatsi. In the thymus of the adult fish, thymic epithelial cells (TECs) characteristic of tonofilaments were observed, with limiting TECs (LECs) found in subcapsular, subseptal, perivascular and nurse-like TECs containing viable intact lymphocytes inside their vacuoles. In addition, three kinds of granulocytes were observed throughout the thymus, and an incomplete blood-thymus barrier was found in the inner zone. Other cell components such as cystic cells, macrophages and plasma cells, were also described in the thymus of the adult S. chuatsi. The thymus development in mandarin fish agrees, to some extent, with the ontogenetic patterns observed in other fish species.

The complete mitochondrial genome of the large yellow croaker, Larimichthys crocea (Perciformes, Sciaenidae): Unusual features of its control region and the phylogenetic position of the Sciaenidae

To understand the systematic status of Larimichthys crocea in the Percoidei, we determined the complete mitochondrial (mt) genome sequence using 454 sequencing-by-synthesis technology. The complete mt genome is 16,466 bp in length including the typical structure of 22 tRNAs, 2 rRNAs, 13 protein-coding genes and the noncoding control region (CR). Further sequencing for the complete CR was performed using the primers Cyt b-F and 12S-R on six L crocea individuals and two L polyactis individuals. Interestingly, all seven CR sequences from L crocea were identical while the three sequences from L polyactis were distinct (including one from GenBank). Although the conserved blocks such as TAS and CSB-1, -2, and -3 are readily identifiable in the control regions of the two species, the typical central conserved blocks CSB-D, -E, and -F could not be detected, while they are found in Cynoscion acoupa of Sciaenidae and other Percoidei species. Phylogenetic analysis shows that L crocea is a relatively recently emerged species in Sciaenidae and this family is closely related to family Pomacanthidae within the Percoidei. L crocea, as the first species of Sciaenidae with complete mitochondrial genome available, will provide important information on the molecular evolution of the group. Moreover, the genus-specific pair of primers designed in this study for amplifying the complete mt control region will be very useful in studies on the population genetics and conservation biology of Larimichthys. (c) 2008 Elsevier B.V. All rights reserved.