Gobiid Fish Research Articles

Two new species of the gobiid fish Trimma from the coral reefs of THE western Pacific Ocean (Pisces; Perciformes; Gobioidei)

Two new species of the gobiid fish genus Trimma are described. Both possess scales in the predorsal midline, have interorbital and postorbital trenches, and lack scales on the opercle. Trimma anthrenum is characterized by an unbranched fifth pelvic fin ray and an almost monochromatic color pattern. When alive, it has a yellow body, and the iris has a pair of blue and black triangles with their bases against the anterior and posterior margins of the pupil (giving the pupil a slit-like appearance), the posterior triangle continues anteroventrally around the pupil margin. Preserved specimens have a very finely outlined diamond pattern across the dorsal half of the body, which otherwise exhibits very few melanophores or chromatophores, a concentration of pigment on the top of the pectoral base, with little pigment on the base itself, a short line of melanophores just above the opercle, and strong basal black bands in the dorsal and anal fins. The species is currently known from Fiji and Tonga. Trimma preclarum is characterized by an elongate second and third dorsal spines and a fifth pelvic ray that may or may not be branched (depending on locality). When alive, Trimma preclarum has three yellow stripes extending along the body, and a red to purple-red iris with four large yellow spots. Preserved specimens have a finely outlined diamond pattern across the dorsal half of the body, and a diffuse, attenuating band of pale brown chromatophores over the abdomen which fades out above the anal fin. The species has been found at Fiji, Palau, Solomon Islands and Papua New Guinea, with underwater photographs from Saipan.

Impacts of salinity and freshwater inflow on oyster-reef communities in Southwest Florida

When assessing oyster-reef habitat in estuaries it is important to understand the influence of salinity on the spatial and temporal variability of associated organisms. How comparable is community structure among stations located at different points along the salinity gradients of estuaries or among tidal tributaries that experience different levels of freshwater inflow? Do assemblages vary seasonally in response to changing salinity and freshwater inflow? To address these questions, multivariate techniques were employed to analyze decapod crustacean and fish abundance data. Organisms were collected at three reefs along the salinity gradient of three estuaries: the Caloosahatchee River and estuary, Estero River and Bay, and Faka Union Canal and Bay. Additional collections were made from reefs located near the mouths of Estero Bay's five tidal tributaries. Samples were dominated by the decapods Eurypanopeus depressus and Petrolisthes armatus. Commonly occurring species included the decapods Panopeus obesus, Alpheus heterochaelis and Rhithropanopeus harrisii and the fishes Gobiosoma robustum, Lophogobius cyprinoides and Gobiesox strumosus. Analysis of similarities suggested differences among stations located along the salinity gradients of all three estuaries. Community structure also varied among stations located near the mouths of the tidal tributaries of Estero Bay. Multidimensional scaling identified community structure present at upper stations as distinct from that downstream and at high-flow tributaries as distinct from that near low-flow tributaries. Upper stations and stations near high-flow tributaries were typified by E. depressus and gobiid fishes. Downstream stations and stations near low-flow tributaries were typified by E. depressus and P. armatus. Percent dissimilarity was greatest when upper and lower stations were compared along the salinity gradient or when low salinity and high-salinity sites were compared among tributaries. Within-station sample variability tended to be higher upstream or in association with high-flow tributaries.

Isolation of microsatellite loci and cross‐species amplifications in three gobiid fish of the genus Pomatoschistus

AbstractGobiids of the genus Pomatoschistus are increasingly being investigated as models for adaptation to coastal environments and for mating system studies. Among the dozen currently analysed species, microsatellite primers have been characterized only for Pomatoschistus minutus. This paper describes seven new polymorphic loci isolated from Pomatoschistus marmoratus and Pomatoschistus microps, two species that hybridize. Cross‐species amplification was tested for these new loci, together with seven already published P. minutus loci. Systematic amplification of samples of each of the three species provided a first indication of their polymorphism.

Inter-group movement of females of the polygynous gobiid fish Trimma okinawae in relation to timing of protogynous sex change

Social conditions and function of inter-group movement of females of the polygynous goby, Trimma okinawae, have been studied at Akamizu Beach, Kagoshima, Japan. Some females moved from their original groups, where the male was still present, to other groups. Before the movement females sometimes temporarily visited the group into which they subsequently moved, suggesting they were able to assess social conditions during the visit. By moving, the females increased in size rank or escaped from similar-sized female competitors in their previous groups. Although the social ranks of the moving females in their original groups were lower than those of the resident females, the ratio of the number of females that changed sex to the number of females surviving at the end of the study did not differ for the two types of female. Inter-group movement of females may increase the probability of their changing sex to become a dominant male.

Habitat Use of Juvenile Fish in the Lower Danube and the Danube Delta: Implications for Ecotone Connectivity

In the lower Danube and the Danube Delta the juvenile fish assemblage has been surveyed in August 2001. In the main channel of the Danube downstream of the town Galati (Romania) and in the Sfintu Gheorghe branch in the Danube Delta altogether 22 sites were sampled by beach seining and electrofishing respectively, covering nine mesohabitats. Altogether 109 beach seine samples and 318 electrofishing points were taken during daylight, to analyze the distribution and abundance of fish species and ecological guilds compared to regulated rivers, to derive conservation targets for the fish community of Central European rivers. A total of 22 412 fish was caught representing 42 species, five of them non-native. Bleak and monkey goby were most abundant and frequent, contributing together 61% to the total catch. The highest fish densities were observed in connected side waters, but substantial amounts of phytophils in the main channel and regular distributions of rheophils and lithophils between main channel and side waters indicated a high ecotone connectivity. Large woody debris was identified as most important habitat structure for riverine cyprinids, whilst its replacement by riprap favors gobiids. Accordingly, habitat alterations and embankments are prerequisites for gobiid fish to invade Central European rivers. River rehabilitation and mitigation measures should provide large woody debris as most important natural in-channel structure and improve the lateral connectivity of main channels to ecotone complexity beneficial for fish.

Fish assemblages in habitats dominated by Caulerpa taxifolia and native seagrasses in south-eastern Australia

Seagrass beds in estuaries are important habitats and nursery grounds for a great vari- ety of fishes, including many economically important species. The introduction of the invasive green alga Caulerpa taxifolia could potentially threaten the seagrasses of south-eastern Australia. This study examined the implications of the spread of C. taxifolia on ichthyofauna in 2 estuaries in central New South Wales. Fish assemblages were compared among adjacent habitats of C. taxifolia and 2 seagrass species (Posidonia australis and Zostera capricorni). Fish were sampled using a small beam trawl to test for differences among habitats in (1) the species composition of the fish assemblages, (2) total abundance and species richness of fishes, and (3) abundances of major fish families. Fish assemblages separated into 3 significantly distinct groupings based on habitat. Total abundances of fishes were similar among habitats; however, species richness was lower in C. taxifolia. The fish assemblages in C. taxifolia were largely characterised by high abundances of gobiid fishes, similar to those in Z. capricorni, and few or no syngnathid and monacanthid species when compared to sea- grass fish assemblages. This suggests that if C. taxifolia competitively replaces native seagrass beds in the estuaries of New South Wales, the resulting change in habitat may also cause a change in fish assemblages. This could reduce the abundances of some protected and economically important fish species but may also increase abundances of other opportunistic fishes.

Functional diversity in extreme environments: effects of locomotor style and substrate texture on the waterfall‐climbing performance of Hawaiian gobiid fishes

AbstractJuveniles of three species of Hawaiian gobiid fishes climb waterfalls during migration to adult habitats using two kinematically distinct patterns: Awaous guamensis and Lentipes concolor use rapid, intermittent bouts of axial undulation (‘powerbursts’), whereas Sicyopterus stimpsoni inches up waterfalls by alternately attaching oral and pelvic suckers to the substrate. Despite the differing kinematics and speed of these behaviors, the extreme demands of locomotion up waterfalls might require similar levels of performance from all climbing goby species. However, the roughness of climbing surfaces might affect performance differently between climbing styles, with rough surfaces decreasing inching performance by impairing the grip of sucking discs on the substrate, but improving powerburst performance by allowing the pectoral fins better purchase as they push against the substrate to start climbing bouts. To test whether species of Hawaiian climbing gobies differ in climbing performance, we filmed multiple individuals of each species as they ascended distances of several body lengths over substrates with three different degrees of roughness. Substantial differences in climbing performance among species were independent of climbing style. For example, the powerburst climber L. concolor always had a faster net climbing speed (speed over 20 cm, including rests between climbing bouts) than the inching climber S. stimpsoni; however, the powerburst climber A. guamensis was similar in net speed to S. stimpsoni, or, on smooth substrates, climbed more slowly. Yet, some differences in performance did emerge between the climbing styles. Substrate roughness did not affect climbing speed in S. stimpsoni, but, as predicted, both powerburst climbers climbed faster on rougher surfaces. In addition, the intermittent motion and rest periods for both powerburst climbers seem of appropriate durations to facilitate an increase in the distance that these species travel before fatigue, but the inching climber S. stimpsoni spent more time in motion than either powerburst climber, and the relative durations of its motion and rest periods seem less likely to convey any performance advantages. These results indicate considerable functional diversity among Hawaiian climbing gobies beyond the two varieties of climbing styles, and show that a wide range of performance capabilities can persist among members of a fauna even under extreme environmental conditions.

The pattern of the mechanosensory lateral line on the caudal fin of the two deep‐water gobiid fishes Deltentosteus collonianus and Deltentosteus quadrimaculatus (Teleostei: Gobiidae)

The most common pattern of the lateral line system on the caudal fin of Gobiidae is characterized by three longitudinal rows of free neuromasts. Deltentosteus collonianus and Deltentosteus quadrimaculatus are two benthic Atlantic–Mediterranean gobiid fishes with additional rows on the caudal fin. In these species the caudal fin is more densely covered by the lateral line system compared to the usual status in Gobiidae. An increase of longitudinal neuromast rows occurs rarely in gobiid fishes and is only known in a few species of Gobiidae with a pelagic lifestyle. Both Deltentosteus species show numbers of neuromast rows on the caudal fin between the plesiomorphic three and the advanced eight rows of pelagic gobies. This intermediate position allows discussion of the existence and the characteristics of an underlying pattern in the increase of the number of longitudinal neuromast rows and adaptation to habitat conditions in Gobiidae.

A morphological study of Acanthocephaloides propinquus (Acanthocephala, Arhythmacanthidae) parasitising gobiid fishes (Teleostei, Gobiidae) in the northwestern Black Sea

AbstractMorphological data for Acanthocephaloides propinquus (Arhythmacanthidae) from gobiid fishes from the northwestern Black Sea are presented. Individuals from the Black Sea differ from the descriptions based on Mediterranean specimens in having 4–5 proboscis hooks per row in the former and 5–6 in the latter. The size of the cuticular spines is rejected as a diagnostic character for A. propinquus because their length varies in a wide range (3.0–7.5 µm). The diagnostic characters for identifying A. propinquus include the presence of small culticular spines, the testes located in the central part of the body and an acanthor having a single hooklet lacking a root.

Range Extensions for Four Estuarine Gobies (Pisces: Gobiidae) in Southern Australia: Historically Overlooked Native Taxa or Recent Arrivals?

SummaryTargeted sampling for gobiid fishes in the Port River estuarine system adjacent to Adelaide, South Australia, identified four previously unrecorded species. Significant range extensions along the east-west coastline of southern Australia are reported for the Australian endemic flatback mangrove goby Mugilogobius platynotus (Günther, 1861), largemouth goby Redigobius macrostoma (Günther, 1861) and Krefft’s frill goby Bathygobius kreffti (Steindachner, 1866) plus the alien Trident goby Tridentiger trigonocephalus (Gill, 1859). Moreover, M. platynotus, R. macrostoma and T. trigonocephalus are new records to the fish fauna of the state of South Australia. While it is clear that T. trigonocephalus has invaded another southern Australian port, there is difficulty in determining the status of the three Australian endemics as being either native to the area or recent introductions (e.g. through ship mediated translocation) due to a previous paucity of sampling and the cryptic nature of goby behaviour that may have prevented historic detection. The long-term existence of suitable habitat on the one hand suggests that these populations are naturally occurring in the Port River. However, a drastically altered estuarine environment, the high incidence of other translocated marine organisms in the system and goby biological traits suiting transportation in ship ballasts or hull fouling conversely casts doubts over their origin. Contrasting management scenarios of conservation versus potential eradication for these newly discovered species highlights a dilemma for biodiversity conservation in an altered environment.

A comparative analysis of helminth faunas and infection parameters of ten species of gobiid fishes (Actinopterygii: Gobiidae) from the north-western Black Sea

The ichthyofauna of the Black Sea is comparatively poor and includes about 200 species (Boltacev 2003). The gobiid fishes (Actinopterygii: Gobiidae) are a large group of approximated by 28 species inhabiting coastal habitats of the Black Sea (Miller 1986, Smirnov 1986, Rass 1993). Five Black-Sea gobiid species are important commercially (Smirnov 1986) and they have also been targeted by anglers. In the north-western Black Sea (NWBS), gobiids can be found in different salinities ranging from fresh water (0.5‰ salinity off the Dniester River mouth) to full-salinity sea water (30‰–35‰ in the Tuzly group of lagoons). These fish make up two groups according to their origin: 1) Ponto-Caspian relict species that are endemics of the Sarmatic and Pontic basins; typical representatives of this group are: Mesogobius batrachocephalus (Pallas, 1811); ACTA ICHTHYOLOGICA ET PISCATORIA (2005) 35 (2): 103–110

CULUWIYA CICHLIDORUM N. SP. (DIGENEA: HAPLOPORIDAE) FROM THE BLACK-BELT CICHLID VIEJA MACULICAUDA (PISCES: CICHLIDAE) FROM NICARAGUA

A new haploporid trematode, Culuwiya cichlidorum n. sp., is described from the intestine of the black-belt cichlid Vieja maculicauda (=Cichlasoma maculicauda (Regan)) from the Atlantic coast of Nicaragua. It differs from congeneric species from freshwater and estuarine mugilid, cichlid, and gobiid fishes, previously placed to Saccocoelioides Szidat, 1954, and Carassotrema Park, 1938, in possessing the intestinal ceca reaching up to the posterior half of the testis and a bipartite, swollen external seminal vesicle. The new species also is characterized by a small, pyriform body, a well-developed prepharynx, a large pharynx, extensive vitelline follicles, confluent posterior to the testis that is situated near the posterior extremity, a uterus limited to the pretesticular and postacetabular region, and few, but relatively large, eggs (67-81 x 36-47 microm, i.e., about 12-14% of the body length) and miracidia without eye-spots. Culuwiya cichlidorum is also reported from Tomocichla tuba (Meek) in Nicaragua and species of Cichlasoma, Herichthys, Oreochromis, Parachromis, Petenia, Theraps, and Vieja from Mexico.

The survival of Sicyopterus stimpsoni, an endemic amphidromous Hawaiian gobiid fish, relies on the hydrological cycles of streams: evidence from changes in algal composition of diet through growth stages fish

Gut contents of larval, juvenile, and adult specimens of the Hawaiian gobiid fish Sicyopterus stimpsoni were examined to catalog the algal flora ingested by this species. The developmental stages of S. stimpsoni examined represented hallmark points in the fish’s life cycle corresponding with major migratory and metamorphic transitions. The algal flora was dominated by diatom species and shifted from taxa representative of a marine, planktonic community in larval fish to a freshwater, benthic community in juvenile and adult fish. This change in diet corresponds with the migration of larval fish to freshwater streams just prior to juvenile development in which rapid modification in mouth anatomy makes ingestion of planktonic algal species difficult. Benthic diatoms from juvenile and adult fish assemblages represented multiple genera that live in a narrow set of environmental conditions. These algae grow during a specific period in the development of the benthic algal community in Hawaiian streams. This suggests a highly specialized dietary behavior that depends heavily on continually restarting the benthic algal successional pattern, which appears to be regulated by the hydrological cycles of streams on the island.

Comparative Ecology of the Gobies Nes longus and Ctenogobius saepepallens, Both Symbiotic with the Snapping Shrimp Alpheus floridanus

We re-examined the symbiotic association of the western Atlantic gobiid fishes Nes longus and Ctenogobius saepepallens with the snapping shrimp Alpheus floridanus on the basis of a critical literature review and new data. Our research confirms that N. longus interacts closely with the shrimp and is dependent on it for the cover provided by the burrow that the shrimp constructs; the goby serves as the sentinel at the burrow entrance. Ctenogobius saepepallens is often seen occupying a burrow of the alpheid, and the shrimp will leave the burrow to deposit sediment with the goby at the entrance, even pushing the goby aside at times. However, the shrimp does not make contact with the goby with its antennae, nor does the goby communicate with caudal fin fluttering at the approach of danger. We suggest that their relationship is a first step in an evolutionary process that may lead to the very close mutualistic association exhibited by N. longus and the alpheid, as well as Indo-Pacific shrimp gobies of 13 different genera and their alpheid partners. Nes longus remains close to the burrow entrance; it feeds mainly on small gastropods, decapod crustaceans, ostracods, and isopods. By contrast, C. saepepallens makes longer excusions from the shelter of the burrow; its diet is dominated by benthic copepods, followed by ostracods and lesser amounts of foraminiferans, isopods, and decapod crustaceans. By virture of its greater mobility, it can be more selective in its prey.

Stable Isotope Analysis of Amphidromous Hawaiian Gobies Suggests Their Larvae Spend a Substantial Period of Time in Freshwater River Plumes

We employed stable isotope analysis (δ13C, δ15N) to evaluate the sources of nutrients used by amphidromous gobiid fishes (Lentipes concolor, Sicyopterus stimpsoni, Awaous guamensis) caught migrating into and living in Hakalau Stream, Hawaii. Although considerable variation amongst the stable isotope values of stream items was noted across all 4 years of our study, the relationships between the fishes were relatively constant. Stable isotope values of recruiting gobies were consistently closer to those of both inshore plankton and freshwater adults than those of offshore plankton, suggesting that the larvae of these species derive much of their nutrition from inshore environments influenced by fresh water. Small differences between the stable values of these species further suggested that their larvae come from different inshore locations. After entering fresh water all species appear to swim rapidly upstream without feeding. Finally, once well upstream, adult L. concolor and A. guamensis appear to assume an omnivorous diet while adult S. stimpsoni rely upon autochthonous production within streams. We propose that freshwater food webs play an integral yet complex role in the lives of both larval and adult amphidromous Hawaiian fishes.

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.

Competition for spawning sites between two gobiid fishes, Bathygobius fuscus and Eviota abax, derived by alteration of mating tactics of the former

Interspecific competition for spawning sites between two gobiid fishes, Bathygobius fuscus and Eviota abax, was studied on a rocky shore. Large males (LM: 55–80 mm in standard length: SL) and small males (SM: 34–52 mm SL) of B. fuscus acted as nest holders and sneakers, respectively, in the early spawning season (July). The sympatric male E. abax (22–33 mm SL) was smaller than SM B. fuscus, and synchronically used rocky holes much smaller than those of LM B. fuscus. In this season, aggressions between the two species were rarely observed. In late season (August), as the number of the LM decreased, the SM converted their tactics to nest holding, occupying nests of a sizes similar to those of E. abax. Eviota abax males were dispossessed by SM and shifted their nest sites to cavities between cobbles and sandy bottom, which might be poorer nest sites than rocky holes.

Molecular cloning and expression of Ad4BP/ SF- 1 in the serial sex changing gobiid fish, Trimma okinawae

Involvement of Ad4BP/ SF- 1 was investigated using the serial sex changing goby Trimma okinawae. First, a cDNA encoding Ad4BP/ SF- 1 was cloned from ovarian follicles. The open reading frame of goby Ad4BP/ SF- 1 encodes a protein of 489 amino acids. Ad4BP/ SF- 1 was expressed in gonadal tissues, brain, and kidney. Second, transcript levels of Ad4BP/ SF- 1 were measured in the ovary and testis of the same individuals. Expressions were related to sexual phases. Moreover, ovarian expression of Ad4BP/ SF- 1 increased during vitellogenesis and declined sharply during the post-vitellogenic period. Finally, the expression profile of Ad4BP/ SF- 1 was measured during serial sex change in the ovary. Ad4BP/ SF- 1 increased in parallel with the onset of the female-phase and decreased as female became male. Therefore, Ad4BP/ SF- 1 probably acts as an important indirect regulator of oocyte growth and maturation at female-phase of serial sex changing gobiid fish T. okinawae.

Aromatase immunoreactivity and the role of enzymes in steroid pathways for inducing sex change in the hermaphrodite gobiid fish Trimma okinawae

The role of aromatase (Arom) in the process of bi-directional sex change in the gobiid fish Trimma okinawae was investigated by immunohistochemical methods. Irrespective of sexual phase, gonads comprised both ovarian and testicular tissues. In each sexual phase of females, the 2nd (2DF-M) and 4th (4DF-M) days after initiation of sex change to male, males, and the 2nd (2DM-F), 4th (4DM-F) and 6th (6DM-F) days after the initiation of reversion from male to female, ovarian and testicular histological observations were made. During the female, 2DF-M, 4DF-M and 6DM-F phases, the ovary contained vitellogenic and previtellogenic oocytes, compared with previtellogenic oocytes in the other phases. Although sperm was found in the testis in every phase, sperm ducts were apparent in the male phase, but not the female phase. Arom immunoreactivity was detected in the interstitial cells between the oocytes in all phases. On the other hand, it was localized in the thecal and granulosa cells of the follicular layer enclosing the oocytes in the female, 2DF-M, 4DF-M and 6DM-F phases. Activity of Arom in the thecal and granulosa cells is thought to be important for the development of oocytes and subsequent sex change.

Promoter analysis of two aromatase genes in the serial-sex changing gobiid fish, Trimma okinawae

Despite numerous endocrine studies on sex change in teleost, no general mechanism that mediates sex change has emerged. The gobiid fish, Trimma okinawae, can change sex in both directions repeatedly. This phenomenon of sex change in goby assigns it as an excellent animal model to elucidate the understanding mechanisms of sex change. In hermaphrodite fishes, estrogen plays a particularly important role in natural and experimentally induced sex change. To investigate the role of estrogen in the serial-sex changing fish T. okinawae, we cloned and analyzed the 5'-flanking regions of P450arom genes from goby genome DNA. Both regions have consensus sequences of TATA, CRE and ERE. Ad4 binding site was restricted in the region of P450aromA. These findings indicate that different regulators control the expression of the two P450arom genes.