A new genus and species of galeommatoid bivalve (Mollusca: Bivalvia: Montacutidae) from Kuwait Bay,Arabian Gulf

Larissamya comta gen. n., sp. n., is described from Kuwait Bay, northern Arabian Gulf. The hinge is identical to that seen in Kurtiella and Montacutona but the spined dorsal margin is unique. Anatomically Larissamya differs from Kurtiella in retaining both gill demibranchs and from both Kurtiella and Montacutona in having greatly unequal adductor muscles. Co-occurrence and density data suggest that L. comta may be associated with the ophuroid Amphiura fasciata.

http://www.zoobank.org/urn:lsid:zoobank.org:pub:ECCB79FC-6EB2-4693-B1D4A014CB17C6D8     

Seasonal absence of fishes in tidepools of a boreal environment (Maine,USA)

Tidepool fishes of a rocky, boreal community in Maine (USA) were sampled periodically from September 1979 to September 1988. Unlike tidepool fish communities in many other areas of the world, those in Maine included no year-round residents. Several of the 22 species among the 1,135 fishes collected occupied tidepools seasonally as nursery areas. In particular, juvenile lumpfish,Cyclopterus lumpus, used tidepools from June to December during their first two years of life. Disappearance of these species from tidepools in winter appeared to be primarily a result of low water temperatures and reduced algal cover in pools.Cooperators are the University of Maine, Maine Department of Inland Fisheries and Wildlife, U.S. Fish and Wildlife Service, and Wildlife Management Institute.     

Patterns of diet overlap between populations of non-indigenous and native fishes in shallow ponds

No significant differences in the diet composition were detected for any of the populations of four non-indigenous fish species (brown bullhead Ameiurus nebulosus , pumpkinseed Lepomis gibbosus , topmouth gudgeon Pseudorasbora parva and eastern mudminnow Umbra pygmaea ) and two native fish species (gudgeon Gobio gobio and roach Rutilus rutilus ), between two small shallow ponds and between habitats within the ponds, during late summer. Based on diet composition, groups of size classes within species ('functional groups') were distinguished. For most functional group combinations of exotic fishes, diet overlap values were low. Although chironomid larvae formed the most important food source, differential consumption of chironomid size classes allowed an important degree of niche differentiation between non-indigenous fishes. In contrast, high diet overlap was found between the functional groups of indigenous gudgeon and of several non-indigenous fishes, indicating a high potential for interspecific exploitative competition. The diet of roach consisted almost entirely of non-animal remains (detritus and plant material). The high proportion of such low-energy food in the diet of this species may be indicative for a competition induced niche shift to suboptimal food sources.     

Digenean species diversity in teleost fishes from the Gulf of Gabes, Tunisia (Western Mediterranean)

This study is the first attempt to survey the diversity of fish digeneans in the Gulf of Gabes (southern coast of Tunisia). A total of 779 fishes belonging to 32 species were sampled. 53 species of Digenea belonging to 15 families were recorded. Among these species, 24 are reported for the first time from the coast of Tunisia. We report one new host record, Lecithochirium sp. from Sardinella aurita. The Hemiuridae is the dominant family. A host-parasite list is presented with the information on the prevalence, abundance and mean intensity of each species collected. The diversity of Digenea is compared with other localities in the Mediterranean Sea and the northern east of Tunisia. The Gulf of Gabes shows the lowest diversity linked to the anthropogenic activities and impact of exotic species. The use of Digenea as indicators of the state of the ecosystem is discussed.     

Community structure of the deep sea fishes in the northern Gulf of Aqaba,Red Sea (Osteichthyes and Chondrichthyes)

The aim of this study was to investigate the community structure of deep sea fishes in the northern Gulf of Aqaba. Deep fish traps, short lines and long lines were deployed at depth ranges from 60 to 700 m between June 2014 and May 2015. A total of 369 fish individuals belonging to 37 species in 21 families were collected. The most abundant family observed in deep fish traps and short line was the commercially important family Sparidae, whereas the most abundant family in long line catch was the commercially unimportant fish family Muraenidae. The most abundant fish species sampled by deep fish traps and shortline was Blueskin Seabream, Polysteganus coeruleopunctatus. The most abundant species in long line catch White-spotted Moray, Gymnothorax johnsoni. In fish traps and with short line, the most commonly caught species was Blueskin Seabream. White-spotted Moray was the most common long line catch. Depth distribution for 37 deep fish species and GIS maps for the two main commercial fish species Blueskin Seabream and Bigeye Hound Shark, Iago omanensis were documented.     

北部湾鱼类碳、氮、磷生态化学计量特征

为探究北部湾鱼类生态化学计量特征,于2021年3月—4月采集分析了北部湾沿岸9个渔港的79种鱼类(382尾)碳(C)、氮(N)、磷(P)含量特征。结果表明北部湾鱼类C、N、P元素含量变化范围分别为33.87%—58.34%、6.31%—14.92%和0.77%—4.67%;C∶N、C∶P、N∶P的变化范围分别为3.43—9.72、19.15—173.06和5.04—33.68,其中P元素含量变化最大,导致C∶P和N∶P的变化。不同物种在科间的差异较大,科内的差异较小。不同体型和食性鱼类之间的C、N、P含量及比值具有显著差异(P<0.05)。鱼类的C∶P和N∶P与P含量呈显著负相关(R²=0.966,P<0.01;R²=0.877,P<0.01),P含量和Ca含量呈显著正相关(R²=0.919,P<0.01),P含量的变化可能与鱼类骨骼和鳞片的形成有关。总之,北部湾鱼类未保持严格的生态化学计量平衡,鱼类生态化学计量特征存在显著的种间差异,主要因鱼类不同的体型和食性差异所致。     

A method for long-term measurement of respiration in intertidal fishes during simulated intertidal conditions

Aquatic and aerial respiration of the amphibious fishes Lipophrys pholis and Periophthalmus barbarus were examined using a newly designed flow-through respirometer system. The system allowed long-term measurements of oxygen consumption and carbon dioxide release during periods of aquatic and aerial respiration. The M o ₂ of L. pholis , measured at 15° C, was 2·1 μmol O₂ g^–1 h^–1 during aquatic and 1·99 μmol O₂ g^–1 h^–1 during aerial exposure. The corresponding values of the M co₂ were 1.67 and 1.59 μmol O₂ g^–1 h^–1 respectively, giving an aquatic respiratory exchange ratio (RER) of 0·80 and an aerial RER of 0·79. The M o₂ of P. barbarus , measured at 28°C, was 4·05 μmol O₂ g^–1 h^–1 during aquatic and 3·44 μmol O₂ g^–1 h^–1 during aerial exposure. The corresponding values of the Mco₂ were 3·29 μmol CO₂ g^–1 h^–1 and 2·63 μmol CO₂ g^–1 h^–1 respectively, giving an aquatic RER of 0·81 and an aerial RER of 0·77. While exposed to air for at least 10 h, both species showed no decrease in metabolic rate or carbon dioxide release. The RER of these fishes equalled their respiratory quotient. After re-immersion an increased oxygen consumption, due to the payment of an oxygen debt, could not be detected.     

浙江乐清湾湿地水鸟资源及其多样性特征

乐清湾是我国具有重要意义的海湾之一。作者于1997、1999和2003年对乐清湾水鸟的分布、数量和多样性特征进行了研究,共观察到54种水鸟,隶属4目7科24属。其中湾口的水鸟物种数、个体数量、多样性指数、均匀度指数以及涉禽所占比例均为最高,湾底次之,湾中部最低。影响这一区域鸟类分布和多样性的因素包括不同区域的滩涂宽度、水动力条件以及有效潮上坪面积等。乐清湾冬季水鸟的物种数呈逐年下降趋势,但年间差异均不显著。除2003年分布于湾底的水鸟个体数量比1999年有所增加外,其他区域都呈逐年下降的趋势,但只有湾口2003年和1997年间的差异显著。鸟类多样性指数和均匀度指数均呈下降趋势,说明适宜水鸟栖息的整体资源环境正逐渐退化,这可能与围垦等人为干扰因素有关。     

Importance of Shallow Water Habitats for Demersal Fishes and Decapod Crustaceans in Penobscot Bay, Maine

We characterized demersal fish and decapod crustacean habitats in 14 shallow (< 12m) areas in Penobscot Bay, Maine, by mapping the distribution of subtidal substrata with an acoustic sea bottom profiler. We identified the aquatic vegetation and the fishes and decapods associated with these habitats. Samples of fishes and decapods in each habitat were collected with a small beam trawl. The seabed at most of the stations sampled was composed of a mosaic of substrata. More species of fishes tow^-1 and higher abundances of fishes and decapods were found in stations with vegetation present, particularly eelgrass, Zostera marina. Decapod species richness tow^-1 was similar between vegetated and unvegetated habitats. Shallow habitats in Penobscot Bay were dominated by juvenile fishes and function as nursery areas. The greater species diversity and higher abundances of epibenthic fishes and decapod crustaceans observed in vegetated habitats, particularly beds of Zostera marina, compared with unvegetated areas in Penobscot Bay conform to the hypothesis that increased habitat complexity results in increased species richness and abundance.The first author is also senior author     

An attempt to restore suitable conditions for demersal fishes and crustaceans in the Port of Sakai-Semboku, north Osaka Bay, Japan

Hypoxia and/or anoxia developed in the summer of 1995 and 1996 in the lower water layer in the Port of Sakai-Semboku, north Osaka Bay, causing an increase in sulfide content and a decrease in the redox potential of the bottom sediment. As a result, the number of benthic animal species was reduced and in the innermost part of the port no benthic animals were found. A jet stream pump system was installed at the Dejima Fishing Port, the innermost part of the Port of Sakai-Semboku to improve the oxygen conditions in the bottom waters. This led to an increase in percentage saturation of oxygen (ca. 10% increase) of the lower seawater layer along with an increase in richness and abundance of benthic fishes and crustaceans in the summer. These findings indicate that dissolved oxygen is a crucial environmental factor in the functioning of the port as a habitat for various benthic animals in north Osaka Bay. Based on the results of field surveys, the possibility of restoration of the benthic fauna by using a jet stream pump system is also discussed.     

Utilization by fishes of shallow,seagrass-covered banks in Florida Bay: 2. Diel and tidal patterns

Synopsis Diel and tidal patterns in the occurrence of water column fishes were examined on four shallow banks in Florida Bay, using continuous 72h gillnet sets. Patterns in capture rates were presumed to indicate movement of fishes on and off the seagrass-covered banks. Species that were nocturnally active on the banks included Arius felis, Mugil gyrans, Opisthonema oglinum, Harengula jaguana, Elops saurus, Lutjanus griseus, and Bairdiella chrysoura. Diurnal species included Eucinostomus gula, Lagodon rhomboides and Mugil cephalus. Strongylura notata and Mugil curema showed no consistent patterns. At the two sites with significant tidal fluctuation in water level, different activity patterns on the bank relative to tidal stage were evident for several species. At extreme low tides, water column fishes apparently left the banks to avoid stranding. Cycles of fish utilization of the bank habitat are proposed to be related to both availability of prey (diel patterns) and water level (tidal patterns). These cycles in turn influence activity patterns of predators foraging on these fishes.     

Utilization by fishes of shallow,seagrass-covered banks in Florida Bay: 1. Species composition and spatial heterogeneity

Synopsis Species composition and relative capture rates of water column fishes occurring on the shallow (<1 m), seagrass-covered mudbanks of Florida Bay were assessed using small-mesh gillnets. The fauna was largely temperate, with few tropical representatives, and was similar to the fish community in adjacent basins. There was a high variability in the catch across the Bay, reflecting heterogeneity in both the physical environment and various aspects of the seagrass canopy. The Gulf site, in the northwestern section of the Bay, had the highest species richness and highest capture rates of individual species, relative to other sites. Higher densities of potential prey, greater available foraging area, and organically rich, fine sediments are probably influential in the greater fish utilization of this bank. The greater exchange of western Florida Bay with open Atlantic or Gulf waters is proposed as a secondary factor influencing species richness; the probability of non-resident species occasionally appearing on western banks is greater than in isolated interior sections of the Bay.     

Relationship between biofouling and growth of the pearl oyster pinctada fucata (Gould) in Kuwait,Arabian Gulf

Results are presented from a three-year investigation of the relationship between accumulations of marine fouling organisms and growth of the pearl oyster Pinctada fucata (Gould). Estimates are provided of the diversity of the foulers, and data on certain hydrological features of the experimental site are also given.There was an inverse correlation between growth of the pearl oyster and diversity of the biofouling assemblages, whatever depth. Growth curves did not follow seasonal variations in the environmental factors very exactly. It was also observed that the polychaete, Polydora vulgaris Mohammad, preferred the oysters planted on the bottom to those suspended near the surface. Bottom oysters suffered the highest mortality, but definite evidence of a relationship between mortality and infestation by the polychaete was not apparent. Percentages of both infestation and mortality were higher among the fouled oysters than those cleaned periodically.     

The importance of mangroves, mud and sand flats, and seagrass beds as feeding areas for juvenile fishes in Chwaka Bay, Zanzibar: gut content and stable isotope analyses

The relative importance of bay habitats, consisting of mangrove creeks and channel, seagrass beds, and mud and sand flats, as feeding grounds for a number of fish species was studied in Chwaka Bay, Zanzibar, Tanzania, using gut content analysis and stable isotope analysis of carbon and nitrogen. Gut content analysis revealed that within fish species almost the same food items were consumed regardless of the different habitats in which they were caught. Crustaceans (mainly copepods, crabs and shrimps) were the preferred food for most zoobenthivores and omnivores, while fishes and algae were the preferred food for piscivores and herbivores, respectively. The mean δ¹³C values of fishes and food items from the mangrove habitats were significantly depleted to those from the seagrass habitats by 6·9 and 9·7‰ for fishes and food items, respectively, and to those from the mud and sand flats by 3·5 and 5·8‰, respectively. Fishes and food items from the mud and sand flats were significantly depleted as compared to those of the seagrass habitats by 3·4 and 3·9‰, for fishes and food, respectively. Similar to other studies done in different geographical locations, the importance of mangrove and seagrass themselves as a primary source of carbon to higher trophic levels is limited. The different bay habitats were all used as feeding grounds by different fish species. Individuals of the species Gerres filamentosus , Gerres oyena , Lethrinus lentjan , Lutjanus fulviflamma , Pelates quadrilineatus and Siganus sutor appeared to show a connectivity with respect to feeding between different habitats by having δ¹³C values which were in-between those of food items from two neighbouring habitats. This connectivity could be a result of either daily tidal migrations or recent ontogenetic migration.