Gobiid Fish Research Articles

Reproductive Biology of the Coral-reef Goby, Asterropteryx Semipunctata, in Kaneohe Bay, Hawaii

A population of the Hawaiian coral-reef goby, Asterropteryx semipunctata, was sampled over a 12-month period to determine basic demographics and reproductive parameters. The sexes did not differ in median length or weight, although the largest males were considerably longer and heavier than the largest females. Overall adult sex ratio was 1 : 1; monthly sex ratios did not differ from unity except in June, when there was a significant female bias. Minimum age at maturity (17.5–19 mm SL) was estimated to be 4.5–5 months after hatching. Nearly all fish over 22 mm SL were mature. Mature females were found in all months of the year, and females that showed evidence of recent or imminent spawning were collected in every month except December. Gonadal analyses indicated a peak in breeding during the summer (May–July) and minimal spawning during the winter (January–February). Between 20% and 30% of females showed evidence of having spawned within the 24-h period prior to collection; therefore, it was estimated that females spawned, on average, at least once every five days and perhaps as frequently as every three days. Mean batch fecundity was 708 eggs (± 418), and was not well predicted by standard length, body weight, or somatic condition. Relative batch fecundity (mean = 1.44 oocytes mg−1 somatic wet weight) varied seasonally, with higher values in spring and summer (April–July) than in fall and winter (September–January). Reproductive parameters are compared and contrasted with those of other gobiid fishes to elucidate general differences between temperate and tropical species.

Female preference of the gobiid fish Eviota abax in relation to elongation of the first dorsal spine in males

The significance of elongation of the first and second spines of the first dorsal fin in male Eviota abax (Gobiidae) was examined in relation to female preference. Reproductive behavior occurred in three phases: male approach to female home, male leading female to nest, and male entering nest. During each phase, the female either accompanied the male or departed. The ratio of positive female mating responses to males before the elongated male dorsal spines were clipped and thereafter was compared in an aquarium. Females preferred male elongated spines in the first phase of courtship, but not in the second phase . Because females may be more exposed to predators during the second phase, owing to conspicuous male courtship, their greater receptivity to elongated dorsal spines in the first phase may decrease predation pressures during subsequent phases of courtship.

Asterropteryx atripes , a new gobiid fish from the Western Pacific Ocean (Perciformes: Gobioidei)

A new gobiid fish, Asterropteryx atripes, is described on the basis of eight specimens from Iriomote-jima Island, Ryukyu Islands, and El Nido, Philippines. It differs from its congeners by having the following combination of characters: 3rd spine of first dorsal fin long, filamentous, distal tip usually over end of 2nd dorsal fin base when appressed in both sexes; pelvic fins almost separated, innermost (=5th) segmented rays connected by rudimentary low membrane between bases, and no frenum; 4–7 short spines on posterior margin of preopercle (the uppermost spine usually just behind the cephalic sensory canal pore N); eye large, 32.3–35.8% of head length; enlarged haemal arches on 1st two caudal vertebrae; a distinct black band from posterior margin of eye to caudal fin base (indistinct in dark-phase individuals); black pelvic fin (vivid in dark-phase individuals); numerous minute bright blue spots on head and body in life; no distinct dark spots on head and body; iris entirely reddish-brown or dusky (bright white ventrally in pale-phase individuals) when alive or fresh, and entirely black in preservation, without white transverse bar on middorsal surface; hovering habit. The new species appears to be most closely related with the other only known hovering species, A. striata; the latter is readily distinguished from the former in having no long, filamentous dorsal spine; semitranslucent pelvic fin; and a series of small black spots along dorsal fin base and dorsal edge of caudal peduncle. Asterropteryx contains two distinct groups, and the monophyly of the genus is open to question.

Individual adjustment of sperm expenditure accords with sperm competition theory.

Sperm competition theory predicts that males should strategically allocate their sperm reserves according to the level of sperm competition, defined as the probability that the sperm of two males compete for fertilizing a given set of ova. Substantial evidence from numerous animal taxa suggests that, at the individual level, sperm expenditure increases when the risk of sperm competition is greater. In contrast, according to the "intensity model" of sperm competition [Parker, G. A., Ball, M. A., Stockley, P. & Gage, M. J. G. (1996) Proc. R. Soc. London Ser. B 263, 1291-1297], when more than two ejaculates compete during a given mating event, sperm expenditure should decrease as the number of competing males increases. Empirical evidence supporting this prediction, however, is still lacking. Here we measured sperm expenditure in two gobiid fishes, the grass (Zosterisessor ophiocephalus) and black goby (Gobius niger), in which up to six sneakers can congregate around the nest of territorial males and release their sperm when females spawn. We show that, in accordance with theory, sneaker males of both species release fewer sperm as the number of competitors increases.

Alternative mating tactics of the gobiid fish Bathygobius fuscus

The reproductive ecology of the gobiid fish Bathygobius fuscus was studied at Nobeoka, Miyazaki, Japan. Males of this species maintain small rock holes as a nest and females spawn an egg mass on the wall of the nest. The males employed two forms of mating tactic: nest holding and sneaking. A nest holder stayed in the nest and waited for a female to visit, whereas a sneaker intruded into a nest while a pair was engaged in reproduction. Males larger than 55 mm standard length were always nest holders; those of smaller size employed both tactics. As the larger males excluded the smaller males, the latter did not occupy a nest hole. With a decrease in the number of larger males, smaller males changed their mating tactic from sneaking to nest holding. The results suggest that male Bathygobius fuscus adopt a conditional strategy whereby they change their tactic depending on their social status.

Diurnal nitrogen excretion rhythm of the functionally ureogenic gobiid fish Mugilogobius abei

This study was performed to determine the daily periodicity of urea excretion in the ureogenic gobiid fish Mugilogobius abei. In 20% seawater, urea excretion of all the fish examined showed daily periodic changes under a 12-h light–dark cycle, and some showed a free-running rhythm under constant darkness. This is the first report of a circadian rhythm in urea excretion in fishes. Daily variations in urea excretion under light–dark cycles were also observed under various conditions, i.e. exposure to water ammonia, confinement/non-confinement and solitary/group. Due to the daily variations in urea excretion, urea contents in tissues changed periodically, whereas enzyme activities related to urea synthesis did not change significantly. The index of urea permeability as determined by changes in body urea contents after 2-h immersion of 25 mM urea solution was high during the peak of daily variation in urea excretion. Locomotor activity and urea excretion showed clear daily variations under light–dark cycles, both of which were diurnal. Furthermore, daily variations in urea excretion were maintained even when the diurnal pattern in the locomotor activity was disturbed. These results suggest that periodic urea excretion was mediated by periodic enhancement of permeability for urea at excretion sites.

A centromeric satellite DNA may be involved in heterochromatin compactness in gobiid fishes.

Centromere and telomere composition and organization were studied in various gobiid species exhibiting and not exhibiting chromosome polymorphisms involving Robertsonian rearrangements. In Gobius cobitis, we isolated an AT-rich centromeric DNA satellite, designated pCOB, and found that several sequences contain adenine stretches, various CA/TG dinucleotide steps, and a sequence 76% homologous to the yeast CDE III centromeric sequence. All of these traits are generally considered important for centromeric function, and the hypothesis has been advanced that some are involved in the control of DNA curvature and thus in the degree of centromeric chromatin compactness. Based on these features, and on the fact that they are found only in the species not exhibiting Robertsonian biarmed chromosomes, a role for pCOB in preventing centric fusions has been hypothesized. Our data also suggest that, as in other species, the formation of Robertsonian biarmed chromosomes is accompanied by the loss of telomeric sequences.

Reproductive Ecology of the Gobiid Fish Eviota abax at Nobeoka, Japan, with Notes on Geographic Variation

The reproductive behavior and spawning cycle of the gobiid fish Eviota abax were observed in a rocky tide pool at Nobeoka, Miyazaki, Japan. Both sexes maintained nonterritorial, overlapping home ranges. The spawnings tookplace at the low tide of neap to spring tidal periods. Matings varied in each spawning cycle, but males did not simultaneously mate with multiple females. Males were larger than females in the spawning pairs. After spawning, only the male guarded the egg mass. Although separated by 900 km, the basic patterns of reproductive ecology were similar at Nobeoka to those reported earlier for this species from Kominato, Chiba, Japan; nest entrances were smaller at Nobeoka than at Kominato, and larger males kept their home ranges longer at Nobeoka.

A New Genus of Small Gobiid Fish (Teleostei, Gobiidae) from the Indo-west Pacific, with Description of Two New Species

A new genus, Tryssogobius, is created for two new species of Indo-west Pacific gobiids (T colini n. sp. and T. longipes n. sp.). The two species are distinguished by differences in fin rays counts, oculoscapular pores, body shape, and coloration. Both species are small, less than 30 mm SL, and occur in relatively deep coral reef habitats, where they hover above the substrate in a manner reminiscent of the microdesmid Nemateleotris.

Fluctuations of nitrogen isotope ratio of gobiid fish (Isaza) specimens and sediments in Lake Biwa, Japan, during the 20th century

Nitrogen isotope ratios (Δ15N) of sediment and formalinߚfixed fish specimens (Isaza fish, Chaenogobius isaza, Tanaka), which had been collected and preserved over 40 yr, were used to provide a new methodology to reconstruct recent eutrophication and historical changes in the nitrogen cycle in Lake Biwa. Δ15N records of Isaza fish collected in the north basin of Lake Biwa, a lake that had been rapidly eutrophicated in the last several decades, showed a rapid increase from the early 1960s to 1980s with an overall amplitude of >3‰. The same trend was simultaneously observed from that of sedimentary nitrogen. We evaluated several factors controlling Δ15N of Isaza fish and sediments during the 20th century and concluded that an increase of Δ15N was either associated with an increase in loading nitrate with high Δ15N values from the watershed or enhanced denitrification in the lake.

Review of the Indo-Pacific gobiid fish genus Lubricogobius , with description of a new species and a new genus for L. pumilus

The gobiid genus Lubricogobius Tanaka, distinctive in being scaleless, without sensory pores, but with sensory papillae on the head, consists of three small species (largest, 33.7 mm SL): the yellow L. exiguus Tanaka, type species, from Japan, with probable records from Taiwan and New Caledonia; L. ornatus Fourmanoir, orange with blue lines on the head, described from Vietnam, recorded from the Arafura Sea, and the range here extended to the Timor Sea and Northwest Shelf of Western Australia, Ryukyu Islands, and to New Caledonia; and L. dinah, a new species from Papua New Guinea and the Ryukyu Islands, white dorsally and abruptly orange-yellow ventrally, with 10–11 dorsal soft rays. L. pumilus Larson and Hoese, known from one 14.5-mm specimen from off Somalia, is referred to the new genus Larsonella. The new genus differs from Lubricogobius in having scales posteriorly on the body, a more slender body, depressed head, no pelvic frenum, the snout longer than orbit diameter, and a different pattern of sensory papillae on the head.

Gobiid fishes from the Cape Verde Islands, including two new species of Gobius (Teleostei: Gobioidei)

Ten species of gobiid fishes (Teleostei: Gobioidei) now listed from the Cape Verde islands fall into several zoogeographical categories, including tropical West African Bathygobius casamancus, Mauligobius nigri, Porogobius schlegelii (unconfirmed) and Vanneaugobius canariensis, tropical amphiatlantic B. soporator and Gnatholepis thompsoni, and Canarian Didogobius kochi. Two new species of the eastern Atlantic, predominantly temperate genus Gobius are described: G. ateriformis sp. nov. and G. tetrophthalmus sp. nov., known so far only from the Cape Verdes, but reported occurrence of the congeneric Atlantic-Mediterranean G. paganellus has not been confirmed. The pattern of free neuromast organs (sensory papillae) of the head lateral-line system in Mauligobius nigri and the habitat of this species are described for the first time and its distribution further discussed. Diversity of gobies and other inshore fishes at the Cape Verdes is briefly indicated.

Gobiid fishes from the Cape Verde Islands, including two new species of Gobius (Teleostei: Gobioidei)

Ten species of gobiid fishes (Teleostei: Gobioidei) now listed from the Cape Verde islands fall into several zoogeographical categories, including tropical West African Bathygobius casamancus, Mauligobius nigri, Porogobius schlegelii (unconfirmed) and Vanneaugobius canariensis, tropical amphiatlantic B. soporator and Gnatholepis thompsoni, and Canarian Didogobius kochi. Two new species of the eastern Atlantic, predominantly temperate genus Gobius are described: G. ateriformis sp. nov. and G. tetrophthalmus sp. nov., known so far only from the Cape Verdes, but reported occurrence of the congeneric Atlantic-Mediterranean G. paganellus has not been confirmed. The pattern of free neuromast organs (sensory papillae) of the head lateral-line system in Mauligobius nigri and the habitat of this species are described for the first time and its distribution further discussed. Diversity of gobies and other inshore fishes at the Cape Verdes is briefly indicated.

Recent Records of Exotic Reptiles on Pohnpei, Eastern Caroline Islands, Micronesia

Recent Records of Exotic Reptiles on Pohnpei, Eastern Caroline Islands, Micronesia Donald W. Buden, D. Brian Lynch, and George R. Zug Abstract Seven nonindigenous species of reptiles (two freshwater turtles, one gekkonid lizard, and four snakes) were recorded on Pohnpei and adjacent Ant Atoll (Federated States of Micronesia) for the first time within the past 15 yr, three within the past 3 yr. They apparently reached Pohnpei by deliberate or inadvertent human-assisted transport, originating from widespread and distant areas including North America, Southeast Asia, Indoaustralia, and other Pacific islands. Pohnpeians (and many other Pacific islanders) often do not perceive exotics as a potential threat to the balance of natural ecosystems. Additional training and education addressing the potentially disastrous consequences of alien species and directed especially toward agencies entrusted with monitoring environmental quality are recommended to help preserve biodiversity on these small island nations. Pohnpei is a ruggedly mountainous (nearly 800 m high), densely forested, sparsely populated (31,540 people censused in 1994 [Office of Planning and Statistics 1996]) volcanic island in the west-central Pacific (Figure 1). It is located 766 km north of the equator. As the political and economic hub of the Federated States of Micronesia, Pohnpei hosts a broad spectrum of international visitors for business and recreation, despite its relatively small size (about 355 km2) and remote location. In addition, yachts in transit from different parts of the world frequently anchor at Pohnpei and its satellite atolls for indefinite periods of time. The potential for deliberate and inadvertent transport of exotic flora and fauna increases with the growing accessibility and popularity of the island. Recent human-assisted transport and establishment of exotic species of plants and animals throughout the Pacific Basin are well recognized (McCoid 1993 from Drake et al. 1989). Guam and the Hawaiian Islands are notorious examples (Eldredge 1988, McCoid 1993, 1995, Fritts and Rodda 1998, Wiles in press) of the disastrous consequences of exotic flora and fauna. This study reports on the probable human-assisted occurrence of seven species of reptiles on Pohnpei and adjacent Ant Atoll recorded for the first time during the past 15 yr, three of them within the last 3 yr. Species Accounts Ocadia sinensis An adult female Chinese stripe-necked turtle (169 mm carapace length [CL]) was collected in a rain-filled rut or puddle near the power plant at Nipaip, about 3.0 km SSW of Kolonia on 16 July 1999. It was found by a local college student and given to a representative of the Fisheries Section of the Department of Economic Affairs; they in turn passed it to biologists at the College of Micronesia, and it is now deposited in the Smithsonian collections (USNM 529967). C. H. Ernst confirmed our identification. Ocadia sinensis is indigenous to Taiwan, southern China, and northern Vietnam (Ernst and Barbour 1989). The Pohnpei specimen is the first record for a west-central Pacific island. It may have been [End Page 65] transported by Asian visitors possibly via international flight or aboard one of the numerous foreign fishing vessels as a "pet" or as alternative food. Although O. sinensis is reported as being herbivorous (Ernst and Barbour 1989), a recent study of its food habits (Chen and Lue 1999:467) revealed it to be "an opportunistic omnivore with both plant and animal matter contributing substantially to the diet" in nature as well as in captivity. The Pohnpei specimen readily consumed small (approximately 20-40 mm standard length) gobiid fishes, as well as hawk moths (Sphingidae) and scincid lizards (Emoia jakati) during its brief period of captivity at the college. Click for larger view View full resolution Figure 1. Location map for Pohnpei and Ant Atoll. AUS, Australia; NG, New Guinea; broken line indicates the equator. Trachemys scripta elegans A female red-eared turtle (170 mm CL) was captured at the public dump at Tekehtik near the Pohnpei airport on 20 January 1997 (Buden in press). It was examined by D.W.B. before being adopted as a "pet" by a government worker. Letters to several government offices pointing out the environmental problems often caused by exotic species and recommending that the turtle be preserved as a voucher specimen were officially...

Environmental factors influencing the gobiid assemblage of a Mediterranean Lagoon: Empirical evidence from a long-term study

A severe freshwater inflow during our long-term ichthyological study of the brackish Vaccares lagoon (1993–1998) helped us to assess the impact of sudden environmental changes on the specific biomass composition of the gobiid population and the catches per unit effort of the black goby Gobius niger, the common goby Pomatoschistus microps and the sand goby P. minutus. In 1993, the composition of the Gobiid fish assemblage of the Vaccares lagoon was dominated by the black goby (63%) and finally evolved to an assemblage dominated by the common goby (80%). The black goby disappeared from the Vaccares lagoon 2 years after the inflow, whereas catches of the common goby increased significantly after the environmental changes and reached maximum values in 1998. Catches of sand goby did not seem to be affected by environmental changes and depended on the communication between sea and lagoon. This study showed that evolution of an ecosystem after environmental changes is linked to the reaction that species developed to face perturbations.

Functional ureogenesis in the gobiid fish Mugilogobius abei.

To examine the transition to ureogenesis, the gobiid fish Mugilogobius abei was immersed in 2 mmol l(-)(1) NH(4)HCO(3) or a (15)N-labelled ammonia solution [1 mmol l(-)(1) ((15)NH(4))(2)SO(4), pH 8.0] for 4-8 days. When exposed to 2 mmol l(-)(1) NH(4)HCO(3) or (15)N-labelled ammonia solution for 4 days, the rate of urea excretion increased to seven times that of the control (in 20 % synthetic sea water) and remained at this level for 4 days. The proportion of nitrogen excreted as urea reached 62 % of total nitrogen excretion (ammonia-N + urea-N). (15)N-enrichment of the amide-N in glutamine in the tissues of fish exposed to (15)N-labelled ammonia was virtually the same as that of ammonia-N: i.e. approximately twice that of urea-N in the excreta and the tissues. Glutamine contents and glutamine synthetase activities in the liver and muscle increased greatly following exposure to ammonia. Urea and citrulline contents in the muscle and whole body of the exposed fish increased significantly, whereas uric acid contents remained unchanged. Carbamoyl phosphate synthetase III (CPSase III) mRNA expression and CPSase III activity were detected in the muscle, skin and gill, but levels were negligible in the liver. Furthermore, all other ornithine-urea cycle (O-UC) enzymes were also detected in muscle, skin and gill. Thus, M. abei clearly shows the transition from ammoniotely to ureotely under ammonia-loading condition and is able to produce urea mainly via the O-UC operating in multiple non-hepatic tissues as a means for ammonia detoxification.

Monogamous Mating System and Spawning Cycle in the Gobiid Fish, Amblygobius phalaena (Gobiidae)

Reproductive ecology and mating system of the gobiid fish, Amblygobius phalaena, were studied on the coral reef at Sesoko Island, Okinawa, Japan. This goby usually lives in pairs, and maintains territories with several burrows for shelter and spawning. Although a few paired individuals changed partners, most pairs remained together over successive rounds of reproduction. Mate guarding by females appeared to prevent males from mating with other females. Spawnings were synchronous with semilunar periods. Several expected spawnings failed to occur (12%). These may have been caused by the delays in spawning preparation of the paired females or by the disturbance caused by a typhoon. A pair spawned in one of the several burrows within their home ranges. Eggs were deposited on the ceiling of the burrow, and were tended by the paired male for 3–4 days until embryos hatched. The males tended eggs at the expense of their feeding. Aggression toward fishes approaching their burrows were exhibited by the males as well as the females. Because of its low frequency in females, this behavior did not limit their ability to feed.

Evolution of a Ureagenic Ability of Japanese Mugilogobius Species (Pisces: Gobiidae)

Abstract Interspecific differences in the ability to excrete urea in four gobiid fishes, Mugilogobius abei, M. chulae, M. sp. 1 and M. sp. 2, in response to elevated external ammonia, were compared and set against the phylogenetic relationships of species, following molecular phylogenetic analyses using a portion of mitochondrially-encoded 12S ribosomal RNA and tRNA-Val genes, which were sequenced from five species of Mugilogobius. The resulting tree, based on 710 base pairs of aligned sequences, was statistically robust and indicated two major clades, (M. abei, M. sp. 1 and M. chulae) and (M. parvus and M. sp. 2), respectively. High ureagenic ability was demonstrated in M. abei and M. sp. 1, being sister species according to the phylogenetic analysis, while the remaining species having a low level of ability. The two former species are restricted to temperate and subtropical Japan, whereas the others are widely distributed throughout tropical Asia. The most parsimonious reconstruction of these features s...

New Record of the Gobiid Fish Feia nympha from Japan and Comments on Its Unique Cephalic Sensory Papillae Rows

New Record of the Gobiid Fish Feia nympha from Japan and Comments on Its Unique Cephalic Sensory Papillae Rows

Sexual competition in an acanthocephalan parasite of fish.

Acanthocephalans are polygamous parasites of vertebrates and some species are known to aggregate in sexual congress to mate. Such a reproductive behaviour could lead to male-male competition for access to females and could have consequences for sexual selection. We dissected 87 gobiid fish, Gobius bucchichii, harbouring 891 acanthocephalans, Acanthocephaloides propinquus. The parasites were sexed and their body sizes were measured. Testicular volume was also evaluated in 82 males in order to establish their phenotypic sexual investment in relation to the estimated sex ratio. We found that parasite intensity (i.e. the number of individuals/fish) was not correlated with fish size, but that parasite size was significantly related to host size. Our results showed that there was a significant relationship between the mean female body size and their number within one host. We found that when the percentage of male parasites in a host increased, presumably increasing male-male competition for access to females, males had a larger testicular volume. We discuss these results in terms of energy allocation, sexual and sperm competition. We conclude that competition for space should be less important for males than competition for access to females. Moreover, increasing testis size should confer advantages to males especially for their reproductive success when sperm competition occurs.