Community structure of soft sediment pool fishes in Moreton Bay, Australia

A survey of soft sediment tide pools was conducted to assess the occupation and assemblage of fishes on three different intertidal shores in Moreton Bay, Australia, between January and December 2009. Tide-pool volume ranged from 0· 30 to 29· 75 l and varied significantly between months and sites. A total of 1364 individuals representing 15 species and nine families of fishes were observed. At Dunwich, fish assemblages were dominated by the sand goby Favonigobius lentiginosus (89%) and whiting, Sillago spp. (10%). At Manly, the gobies Favonigobius exquisitus (37%), Pseudogobius sp. (31%) and the blenny Omobranchus punctatus (19%) dominated the shores while at Godwin Beach, F. lentiginosus (15%), F. exquisitus (45%) and Sillago spp. (25%) were the most abundant species. The mean ±s.e. density of fishes ranged from 0· 29 ± 0· 13 to 5· 04 ± 1· 74 fishes l(-1) and abundance of fish correlated with pool volume. Juveniles (75%) dominated assemblages suggesting that soft sediment pools may act as nurseries. The persistent and recurrent fish assemblages found in soft sediment tide pools in Moreton Bay suggest that these shores are behaving more like a tropical than a temperate climate shore, as there was no significant difference of fish abundances between seasons.     

A new type of fish olfactory organ structure in Periophthalmus barbarus (Oxudercinae)

Kuciel, M., ?uwa?a, K., Jakubowski, M. 2011. A new type of fish olfactory organ structure in Periophthalmus barbarus (Oxudercinae). —Acta Zoologica (Stockholm) 92 : 276–280. The study describes a new type of olfactory organ structure in teleost fish, the Atlantic mudskipper Periophthalmus barbarus (Gobiidae). The nasal cavity in this species consists of a tube‐like elongated canal widening to a chamber‐like sac in the preorbital part of the head. The olfactosensory epithelium (studied by light and electron microscopy) occurs only in the form of islets located along the medial wall of the tube‐like part of the organ. The presence of a chamber‐like sac without an olfactory rosette or olfactosensory epithelium suggests that a mechanism allowing water circulation is in operation.     

Otolith microchemistry of tropical diadromous fishes: spatial and migratory dynamics

Otolith microchemistry was applied to quantify migratory variation and the proportion of native Caribbean stream fishes that undergo full or partial marine migration. Strontium and barium water chemistry in four Puerto Rico, U.S.A., rivers was clearly related to a salinity gradient; however, variation in water barium, and thus fish otoliths, was also dependent on river basin. Strontium was the most accurate index of longitudinal migration in tropical diadromous fish otoliths. Among the four species examined, bigmouth sleeper Gobiomorus dormitor, mountain mullet Agonostomus monticola, sirajo goby Sicydium spp. and river goby Awaous banana, most individuals were fully amphidromous, but 9–12% were semi‐amphidromous as recruits, having never experienced marine or estuarine conditions in early life stages and showing no evidence of marine elemental signatures in their otolith core. Populations of one species, G. dormitor, may have contained a small contingent of semi‐amphidromous adults, migratory individuals that periodically occupied marine or estuarine habitats (4%); however, adult migratory elemental signatures may have been confounded with those related to diet and physiology. These findings indicate the plasticity of migratory strategies of tropical diadromous fishes, which may be more variable than simple categorization might suggest.     

Comparative morphology of the sagittal otolith in three species of south Caspian gobies

Sagittal otolith shapes were investigated in order to identify three sympatric species of south Caspian gobies (Caspian goby Neogobius caspius, deepwater goby Ponticola bathybius and bighead goby Ponticola gorlap). The sagittal otoliths in P. bathybius have a rectangular shape and are thick, whereas in N. caspius they are relatively round and thin. In P. gorlap, otoliths have an elongated shape and are relatively thick. The noticeable difference among the otoliths of the three species is the presence of one anterior and one posterior projection in the otoliths of N. caspius and P. gorlap. Among shape indices, form factor (irregularity of surface area), circularity, aspect ratio and rectangularity are the foremost that indicate interspecific variability. The canonical discriminant analysis correctly classifies 94·7% of the original group cases. The overall analyses show the relevance of applying otolith shape for interspecific distinction of the three species of Caspian gobies.     

Genetic and biogeographic relationships of the racer goby Neogobius gymnotrachelus (Gobiidae: Teleostei) from introduced and native Eurasian locations

The racer goby Neogobius gymnotrachelus , along with several other neogobiin fishes, has been spreading north and west from its native Ponto-Caspian range for the past two decades via shipping and canals. It has been predicted as a likely future invader of the North American Great Lakes, where it would join its neogobiin relatives – the round and freshwater tubenose gobies. The present study is the first to analyse the population genetic and biogeographic relationships of the racer goby, establishing a baseline to aid interpretation of its future spread patterns and likely donor-recipient population relationships. The mitochondrial DNA cytochrome b gene was sequenced from representative areas of the racer goby's range, including rivers of the northern Black Sea and areas of spread upstream in the Danube River and outside the Ponto-Caspian region to the Vistula River in Poland. Results discerned nine haplotypes, with few shared among drainages of native rivers and most sites housing unique alleles. Racer goby populations significantly diverged among watersheds, supporting historic low migration and little non-anthropogenic gene flow. The Dnieper River was identified as a likely donor source for the Vistula River colonization, where appreciable variability suggests a relatively large number of founding genotypes.     

中国广东省虾虎鱼一新种——周氏吻虾虎鱼(Rhinogobius zhoui)(鲈形目:虾虎鱼科)

记述了分布于广东省海丰县莲花山溪流中的吻虾虎鱼属一新种,定名为周氏吻虾虎鱼Rhinogobius zhoui。该新种可由如下特征区别于相近种：第二背鳍条I, 8—9;臀鳍条I, 7—8;胸鳍条16—18;纵列鳞29—31;背鳍前鳞10—12;椎骨数10+16=26;成年雄性个体第一背鳍无黑斑,各奇鳍具宽大的亮白色边缘,颊部与鳃盖膜无斑纹,体侧具6—8个红色斑块。     

Molecular phylogeny of gobioid fishes (Perciformes: Gobioidei) based on mitochondrial 12S rRNA sequences

The molecular phylogeny of the gobioid fishes, comprising 33 genera and 43 valid species, was examined by use of complete mitochondrial 12S rRNA and tRNA(VAL)genes. Both parsimony and neighbor-joining analyses revealed comparable results and are generally congruent with those of morphological studies. The Odontobutis, which was always placed at the base of the phylogenetic trees, can be treated as a sister group of all other nonrhyacichthyid gobioids. Within eleotrid fishes, the monophyly of the Eleotrinae is strongly supported by molecular data. The Butinae is closer to fishes with five branchiostegal rays and should be treated as a sister group of the latter. The group with five branchiostegal rays, except for sicydiines, can be divided into two groups according to their epural counts. Fish with one epural, the Gobiinae of Pezold plus Microdesmidae, form a monophyletic group which is sister to those with two epurals, the Oxudercinae and Gobionellinae of Pezold. However, Sicydiinae, which have one epural, are closer to the Oxudercinae and Gobionellinae rather than to the Gobiinae. Since progressive reduction in epural number has been observed along this lineage, the sicydiines should be treated as a derived group within the groups with two epurals.     

Ship Mediated Fish Invasions in Australia: Two New Introductions and A Consideration of Two Previous Invasions

Two species of fishes, the northwest Pacific Acentrogobius pflaumi (Bleeker 1853) (Perciformes: Gobiidae) and the New Zealand Forsterygion lapillum Hardy (1989) (Perciformes: Tripterygiidae), are newly reported as recent introductions in Port Phillip Bay, southeastern Australia. Forsterygion lapillum is restricted to a commercial port in the western area of the bay, while A. pflaumi occurs in all areas of the bay except the entrance. Both species are among the most abundant fishes collected in occupied habitats. It seems probable that they were introduced as eggs, larvae or juveniles in ships ballast water. While both A. pflaumi and F. lapillum appear to be well suited to conditions in Australia, populations of two previously introduced marine fishes (the gobiidsAcanthogobius flavimanus and Tridentiger trigonocephalus) have failed to rapidly expand their distributions and seem to be controlled by factors yet to be determined.     

Phylogeography of marine mutualists: parallel patterns of genetic structure between obligate goby and shrimp partners

The survival of many organisms depends on interspecific, mutualistic interactions. Hence, it is important to assess the phylogeography of multiple mutualistic species simultaneously to gain insight into how their metapopulations persist, spread and recover from disturbance. Consequently, we sequenced mitochondrial DNA (cytochrome b) from a gobiid fish (Ctenogobiops feroculus) and its mutualistic partner, an alpheid snapping shrimp (Alpheus djeddensis). These obligate mutualists are common in shallow coral reef lagoons, and we collected individuals from 11 Indo-Pacific islands that were likely exposed to different disturbance histories due to sea level fluctuations associated with glaciation events [geological studies indicate that eastern oceanic islands (Cook Islands, French Polynesia) were more disturbed than western continental plate islands that have deeper, more extensive lagoons (Okinawa, Fiji)]. Both phylogenetic and population genetic analyses indicated that gobies from Okinawa and Fiji were genetically distinct both from each other and those in the Cook Islands and French Polynesia. Shrimp, by contrast, grouped into two distinct genetic groups that showed no geographic structure. Restricting the analysis to one clade of shrimp, which contained two-thirds of the individuals, showed that these shrimp had very similar phylogeographical structure to the gobies. Mismatch distributions demonstrated that both gobies and shrimp experienced a recent, rapid population expansion into French Polynesia. Finally, nucleotide and haplotype diversities per sample location were significantly correlated between mutualists and tended to be higher on western continental than eastern oceanic islands. Our results suggest that these mutualists recovered from a major disturbance by colonizing South Pacific islands in synchrony.