Lernanthropid copepods (Siphonostomatoida) parasitic on fishes of the Gulf of Thailand

Five species of copepods (Siphonostomatoida: Lernanthropidae) parasitic on fishes of the Gulf of Thailand are reported. They are: Lernanthropus corniger Yamaguti, 1954 from Megalaspis cordyla (Linnaeus); L. latis Yamaguti, 1954 from Lates calcarifer (Bloch); L. nemipteri Jayasree & Pillai, 1976 from Scolopsis lineata Quoy et Gaimard; L. sillaginis Pillai, 1963 from Priacanthus tayenus Richardson; and Norion tayenus n. sp. from P. tayenus. Except for L. sillaginis, the remaining four species are new to Thailand. Lernanthropus priacanthi Kirtisinghe, 1956 is transferred to Norion as N. priacanthi (Kirtisinghe, 1956) n. comb.     

DNA barcoding of marine fishes from Saudi Arabian waters of the Gulf

We used the cytochrome oxidase subunit I (coI) gene DNA to barcode 117 endemic Gulf and cosmopolitan Indo–West Pacific fish species belonging to 54 families and 13 orders. Novel DNA barcodes were provided for 18 fish species (Trachinocephalus sp., Nematalosa sp., Herklotsichthys lossei, Upeneus doriae, Trachurus indicus, Apogonichthyoides taeniatus, Verulux cypselurus, Favonigobius sp., Suezichthus gracilis, Sillago sp., Brachirus orientalis, Pegusa sp., Lepidotrigla bispinosa, Lepidotrigla sp., Grammoplites suppositus, Hippichthys sp., Paramonacanthus sp. and Triacanthus sp.). The species delimitation analysis, conducted with Poisson tree processes– Bayesian PTP (PTP–bPTP) and nucleotide-divergence-threshold (NDT) models), found 137 and 119 entities respectively. Overall, NDT method, neighbour-joining species tree and the prior taxonomic assessment provided similar results. Among the 54 families considered, only 10 (Ariommatidae, Ephippidae, Leiognathidae, Nemipteridae, Plotosidae, Pomacanthidae, Pomacentridae, Priacanthidae and Rachycentridae) showed the occurrence of molecular diagnostic pure characters. The DNA barcoding database developed during this study will help ichthyologists to identify and resolve the taxonomic ambiguities they may encounter with the fishes occurring in The Gulf and throughout the region.     

Fishery-induced changes in a marine ecosystem: insight from models of the Gulf of Thailand

Two mass-balance trophic models are constructed to describe the Gulf of Thailand ecosystem (10–50 m depth): one model pertains to the initial phase of fisheries development, and the other to when the resources were severely depleted. The two phases are compared, and changes brought about by fishing discussed. A dynamic simulation model, Ecosim, is then used successfully to reproduce the 1980 state of the fishery based on the 1963 model and the development in catches. In addition the 1980 model is used to predict how the ecosystem groups may bounce back following marked reduction in fishing pressure. Finally, the 1963 model is used to study alternative scenarios for how the fisheries development could take place, notably the effect of exploiting only the resources of larger species. The study validates that the Ecosim model can be used to predict ecosystem level changes following changes in fishing pressure, therefore fishing induced changes can to a large extent explain the changes in ecosystem pools and fluxes observed over time.     

Influence of initial substratum surface tension on marine micro- and macro-fouling in the Gulf of Thailand

The density of five major groups of fouling organisms (bacteria, diatoms, choanoflagellates, ciliates, macroorganisms) on seven artificial substrata with surface tensions between 19.0 and 64.5 mN m⁻¹ was studied in the Gulf of Thailand. Two series of test panels of the different substrata were immersed into the sea between 3 hours and 64 days (macrofauna 128 days). The results show that surface tension has a limited impact on the density of the organisms. Only bacteria settled continuously in significantly lower numbers on materials within the minimum bioadhesive range (20–25 mN m⁻¹) than on other substrata. Significant differences between the substrata may disappear after long exposure, as in series 2 after 16 days. For diatoms and protozoa, a colonisation pattern similar to that of bacteria with a minimum of 20–25 mN m⁻¹ was detected after several exposure intervals. However, it was never recorded in more than 3 exposure intervals in a row. The colonisation pattern of macroorganisms could not be attributed to substratum surface tension. An index, called “colonisation degree” is introduced to give a general impression of the density of organisms on the materials tested. The colonisation degree did not show any significant difference at any exposure interval. The present results clearly suggest that substratum surface tension is easily overshadowed by other factors in colonisation processes under natural conditions. *** DIRECT SUPPORT *** A03B6037 00003     

Two new species of Cyprinoid fishes from the fauna of Phu Quoc Island, Gulf of Thailand, Vietnam

Two new Cyprinoid species are described from Phu Quoc Island, Gulf of Thailand. The first new species, Barbucca elongata sp. nova (Balitoridae), differs from the species B. diabolica, which is described previously, in more elongated body covered by small scales (50–67 perforated lateral line scales), conical snout, and coloration. The second new species, Rasbora vietnamensis sp. nova (Cyprinidae), belongs to the species group “R. trifasciata”; it differs from other species of the group in substantially reduced lateral line system with four-seven perforated scales and absence of red pigmentation on the fins and body.     

Water quality management for low temperature marine fishes in space.

Vestibular Function Experiment Unit (VFEU), one of the Spacelab facility flown in Neurolab mission (STS-90) in April, 1998, was to support neurophysiological research using a marine fish, Opsanus tau (oyster toadfish). The functions of the VFEU were primarily a quality management of environmental water during the mission at 14 degrees C and for acquiring physiological signals from implanted micro-electrodes in the otolith nerves as well as the spatial acceleration of the fish. A key element of the life support system was a balanced biological filter containing two types of nitrifying bacteria, Nitrosomonas for ammonia oxidization and Nitrobacter for nitrite oxidization. Although the 16 days mission was successful, two toadfishes died in late phase of the mission. Ammonium concentration in those two life support systems elevated to remarkably high level at the end of the mission whereas the other two indicated very low. This report summarizes the results of the water quality management of the VFEU during the Neurolab mission based on analysis of water samples taken during the flight and those taken prior and just after the flight.     

Clostridium botulinum in the Gulf of Thailand.

A survey was carried out to determine the incidence of Clostridium botulinum in samples of mud, sand, and fish from the Gulf of Thailand. Enrichment cultures from 762 samples of mud and sand from seven different areas around the Gulf were tested. C. botulinum type D was present in 10 samples, and type E was present in 2 samples taken from the west coast at Hua Hin. Enrichment cultures from 16,773 fish grouped into 2,151 samples yielded 10 filtrates containing C. botulinum type D and 5 containing type E. All of the toxic filtrates were obtained from samples of fish taken from the west coast of the Gulf of Thailand.     

Clostridium botulinum in the Gulf of Thailand.

A survey was carried out to determine the incidence of Clostridium botulinum in samples of mud, sand, and fish from the Gulf of Thailand. Enrichment cultures from 762 samples of mud and sand from seven different areas around the Gulf were tested. C. botulinum type D was present in 10 samples, and type E was present in 2 samples taken from the west coast at Hua Hin. Enrichment cultures from 16,773 fish grouped into 2,151 samples yielded 10 filtrates containing C. botulinum type D and 5 containing type E. All of the toxic filtrates were obtained from samples of fish taken from the west coast of the Gulf of Thailand.     

Monogamy in marine fishes

The formation of long-term pair bonds in marine fish has elicited much empirical study. However, the evolutionary mechanisms involved remain contested and previous theoretical frameworks developed to explain monogamy in birds and mammals are not applicable to many cases of monogamy in marine fish. In this review, we summarise all reported occurrences of social monogamy in marine fish, which has so far been observed in 18 fish families. We test quantitatively the role of ecological and behavioural traits previously suggested to be important for the evolution of monogamy and show that monogamous species occur primarily in the tropics and are associated with coral reef environments in which territory defence and site attachment is facilitated. However, there is little evidence that obligately monogamous species are smaller in body size than species that can adopt a polygynous mating system. We review the evidence pertaining to six hypotheses suggested for the evolution of monogamous pair bonds: (1) biparental care, (2) habitat limitation, (3) low population density/low mate availability/low mobility, (4) increased reproductive efficiency, (5) territory defence, and (6) net benefit of single mate sequestration. We outline predictions and associated empirical tests that can distinguish between these hypotheses, and assess how generally each hypothesis explains monogamy within and between breeding periods for species with different types of territories (i.e. feeding only or feeding and breeding). Hypotheses (1) and (2) have limited applicability to marine fishes, while hypotheses (3)-(5) have little empirical support beyond the species for which they were designed. However, the role of paternal care in promoting monogamous pair bonds is not explicit in these hypotheses, yet paternal care has been reported in more than 70 monogamous marine fish. We show that paternal care may act to increase the likelihood of monogamy in combination with each of the proposed hypotheses through decreased benefits to males from searching for additional mates or increased advantages to females from sequestering a single high-quality mate. Among species defending breeding and feeding territories, the benefits, both within and between reproductive periods, of sequestering a single high-quality mate (hypothesis 6) appear to be the best explanation for socially monogamous pairs. For species without parental care (i.e. holding only feeding territories), territory defence (hypothesis 5) in combination with the benefits of guarding a large mate (hypothesis 6) could potentially explain most instances of monogamy. Empirical studies of marine fishes over the past two decades are therefore slowly changing the view of monogamy from a mating system imposed upon species by environmental constraints to one with direct benefits to both sexes.     

Lipids of marine cold-water fishes

The study deals with the lipid and fatty acid compositions of the muscles, gills and liver of marine fishes inhabiting cold waters (0.5–6°C) and caught in Peter the Great Bay (3 species) and Vostok Bay (2 species), as well as with the fatty acid compositions of the main phospholipids in the muscle tissues of fish from Olyutorskii Bay (4 species). The average content of phosphatidylcholine was about 60% in muscles and in the liver and 53.8% of the sum of all phospholipids in gills. The phosphatidylethanolamine content was on the average 24.3, 25.1 and 22.3% in muscles, liver and gills, respectively. Increased contents of phosphatidylserine and sphingomyeline were recorded in the gills. The mean (S.D.) molar ratios of cholesterol/phospholipids were 0.20, 0.32, and 0.58 in the muscles, liver, and gills, respectively. It was established that phosphatidylcholine has a higher content of saturated fatty acids, whereas phosphatidylethanolamine was richer in monoenic acids and docosahexaenoic acid (DHA). It was noted that the level of polyenic fatty acids was increasing and the level of monoenic and saturated acids was decreasing in the series from gills-liver-muscles. The species with a more active mode of life were distinguished by an increased content of docosahexaenoic acid.     

DNA barcoding Indian marine fishes

DNA barcoding has been adopted as a global bio-identification system for animals in recent years. A major national programme on DNA barcoding of fish and marine life was initiated in India by the authors during 2006 and 115 species of marine fish covering Carangids, Clupeids, Scombrids, Groupers, Sciaenids, Silverbellies, Mullids, Polynemids and Silurids representing 79 Genera and 37 Families from the Indian Ocean have been barcoded for the first time using cytochrome c oxidase I gene (COI) of the mtDNA. The species were represented by multiple specimens and a total of 397 sequences were generated. After amplification and sequencing of 707 base pair fragment of COI, primers were trimmed which invariably generated a 655 base pair barcode sequence. The average Kimura two parameter (K2P) distances within species, genera, families, orders were 0.30%, 6.60%, 9.91%, 16.00%, respectively. In addition to barcode-based species identification system, phylogenetic relationships among the species have also been attempted. The neighbour-joining tree revealed distinct clusters in concurrence with the taxonomic status of the species.     

Bone lipids of marine fishes.

Assessment of candidates for investigation of bone lipid metabolism yielded the following findings. (1) A tropical marine butterflyfish, Chaetodon ornatissimus, had oil-filled bones (66-80% lipid, percent dry weight) hence may be a suitable condidate. (2) The tropical marine fishes Exallias brevis, Pomacentrus jenkensi, and Chromus agilis, and a Canadian fish Sebastes ruberrimus, had intermediate quantities of oil in their bones (12-49% lipid). (3) In all the foregoing species the major bone lipid was triglyceride, usually more abundant in skull than spine. Sterol and phospholipid were also present. (4) The major fatty acids of the triglycerides (and phospholipids) were 16:0, 18:0, 18:1, and C20, C22 acids. Those acids were dominated by 20:4, 20:5, 22:5, and 22:6. (5) There was more total unsaturation in the bone lipids of S. ruberrimus (from 10 degrees C water; 67-72% unsaturation) compared to the tropical fish (from 25 degrees C water; 32-67% unsaturation) with the exception of E. brevis. (6) One of the tropical species (Arothron meleagris) and a Canadian Chimaeran (Hydrolagus colliei) contained only 1-3% lipid in their bones.     

Spawning period of Mediterranean marine fishes

We collected all available information (i.e. international and local journals, conference proceedings, theses, technical reports) on the spawning season (n = 511 stocks, 168 species), gonadosomatic index (n = 237 stocks, 81 species) and sex ratio (n = 97 stocks, 68 species) of Mediterranean marine fish. The 511 stocks represented 20 orders (most were Perciformes, 283 stocks) and 65 families (most were Sparidae: 17 species and 63 stocks). Overall, 346 stocks (128 species) spawned between April and August, 139 stocks (60 species) between September and March, while the remaining 26 stocks (13 species) were all-year-round spawners. In addition, 174 stocks (34.1%) were characterised by an extended (>4 months) spawning season, but, for most stocks (332 stocks, 64.4%), spawning duration ranged from 2 to 4 months inclusive. Regardless of the onset and the duration of spawning, the spawning period of 284 and 287 stocks included June and July, respectively, indicating that most Mediterranean species are summer spawners. Female gonadosomatic index ranged between 0.06 and 37 (mean ± SE = 8.55 ± 0.647, n = 95) and was significantly higher (t-test: t = 5.58, P < 0.001) than the corresponding male one, which ranged between 0.06 and 30 (mean ± SE = 4.21 ± 0.431, n = 95). Congeneric species that occupied the same area and share the same requirements exhibited successive and non-overlapping spawning (e.g. Sparidae in the Adriatic Sea, Mugilidae in the Ionian Sea and Tunisian waters). The knowledge of the spawning period coupled with information on spawning and nursery grounds and detailed knowledge of mating systems, social interactions, maturity and fecundity may be very useful for fisheries management.     

Status of marine larviculture in Thailand

Aquaculture has become important for the economy ofThailand, especially the culture of the tiger shrimp(Penaeus monodon). In addition, there are otherimportant cultured species, those are seabass (Lates calcarifer), grouper (Epinepheluscoioides), mullet (Liza subviridis), and bananashrimp (P. merguiensis). In order to meet theexpanding needs of aquaculture, larviculture of thesespecies has also been practiced in Thailand. Actually, the broodstocks of cultured species spawnnaturally in captivity. Success in larval rearing hasbeen achieved as a result of experience andmanagement. Rearing of larvae is generally done inconcrete tanks. Water quality management in larvaltanks including the foods used in rearing, are themain factors affecting the success of this activity.Since excess food left in the tank causes both directand indirect notorious losses in larviculture, the useof live food in shrimp culture can contribute to waterquality and prevent the occurrence of diseases.Several species of phytoplanktons and zooplanktonsincluding Chlorella, Chaetoceros, Skeletonema, Brachionus, Artemia and Moina are used in larval feeding. Larvae aregenerally fed with these live food at least for twoweeks or even longer, e.g., for nearly two months inrearing grouper larvae. Enrichment of food organismshas been found to be essential just for some species,e.g., n-3HUFA for grouper larvae.In Thailand, plankton organisms grow fast most of thetime. For example, Skeletonema needs less than24 h to reach the peak of production, Brachionuscan reach maturity within 12 h and increases 5–7 timesd^-1, whereas Moina reaches the maturestage within 24 h and increases 6–8 times/2–3 days.The production of these microorganisms could, thus, beprofitably used for the larviculture.     

Anisakidae larvae found in marine fishes and squids from the Gulf of Tongking, the East China Sea and the Yellow Sea.

Marine fishes and squids caught in the Gulf of Tongking, the East China Sea and the Yellow Sea were dissected, and many Anisakidae larvae were found in them. The larvae of Anisakis simplex (Anisakis Type I larvae), the most important causative agent of anisakiasis, was found in about 30% of fishes and squids caught in the Gulf of Tongking and in about 60% of those caught in the East China Sea and the Yellow Sea. Larvae belonging to three other genera than Anisakis--Raphidascaris or Raphidascaroides, Hysterothylacium, and Terranova (Cannon Type I)--were also detected.     

Phosphoglucose isomerase isozymes in teleostean fishes from the Arabian Gulf

Two phosphoglucose isomerases (PGI) with different electrophoretic mobilities have been found in all groups of teleostean fishes studied, with the exception of the Clupeomorpha. PGI proved to be a good taxonomic criterion to differentiate members of the Nemipteridae, Sciaenidae, Platycephalidae and Stromateidae from the other teleost families.     

Response of coastal fishes to the Gulf of Mexico oil disaster

The ecosystem-level impacts of the Deepwater Horizon disaster have been largely unpredictable due to the unique setting and magnitude of this spill. We used a five-year (2006-2010) data set within the oil-affected region to explore acute consequences for early-stage survival of fish species inhabiting seagrass nursery habitat. Although many of these species spawned during spring-summer, and produced larvae vulnerable to oil-polluted water, overall and species-by-species catch rates were high in 2010 after the spill (1,989±220 fishes km-towed(-1) [μ ± 1SE]) relative to the previous four years (1,080±43 fishes km-towed(-1)). Also, several exploited species were characterized by notably higher juvenile catch rates during 2010 following large-scale fisheries closures in the northern Gulf, although overall statistical results for the effects of fishery closures on assemblage-wide CPUE data were ambiguous. We conclude that immediate, catastrophic losses of 2010 cohorts were largely avoided, and that no shifts in species composition occurred following the spill. The potential long-term impacts facing fishes as a result of chronic exposure and delayed, indirect effects now require attention.