Shallow-water Species Research Articles

Spatio-temporal distribution of soft-bottom epibenthic fauna on the Cilician shelf (Turkey), Mediterranean Sea

Spatio-temporal distribution of epifauna collected with a sledge was studied on the Cilician shelf of the Mediterranean Sea. There were two different communities: the shallow community was restricted to water at 5 and 10 m deep with sandy bottom inhabited abundantly by Conomurex persicus, Arnoglossus laterna and Murex trunculus. Conomurex persicus, an introduced tropical species predominated the shallow zone and distinguished it from the deep zone. The deep community (25-150 m) lacked shallow water species and was dominated by Arnoglossus laterna, Goneplax rhomboides and Parapenaeus longirostris. Seasonality was not a major factor in the epibenthic community structure of the entire shelf, but it is in the shallow waters. Bottom depth was main factor for structuring the community on the shelf. Sediment size and organic content is also a controlling factor for the distribution of the epibenthic fauna.

Larval development of <i>Dagetichthys marginatus</i> (Soleidae) obtained from hormone-induced spawning under artificial rearing conditions

Dagetichthys marginatus (formerly Synaptura marginata ) larvae were laboratory-reared from wild caught adult broodstock as part of an aquaculture research project in temperate South Africa. A larval description for the species is provided in this paper. This work also represents the first larval description for the genus Dagetichthys , which is represented by five species, three of which occur in the western Indian Ocean. Larval development in D. marginatus is typical of Soleidae. Dagetichthys marginatus larvae are heavily pigmented, with four characteristic melanophore “blotches” on the finfold. These larvae are easily distinguished from other soleid larvae commonly encountered in temperate South Africa based on the large size at flexion (5-7.06 mm BL) and the heavily pigmented body. Laboratory-reared postflexion larvae in this study showed similar meristic counts to those of wild caught adult fish. Despite the common occurrence of mature adults of this species in shallow marine waters off temperate South Africa, larvae are absent from nearshore ichthyoplankton catches. As yet, the spawning strategy of the species is unknown.

Morfología de la primera zoea de los cangrejos marinos Petrolisthes haigae y P. nobilii (Decapoda: Porcellanidae)

The porcellanid crabs Petrolisthes haigae Chace 1962, and P nobilii Haig 1960, are shallow-water species distributed along the tropical Eastern Pacific shores. Larvae of both species from eight and four females, collected at Taboga and Naos Islands, respectively, were hatched in the laboratory. First zoeal stages of these species are described and illustrated for the first time and compared to previously first zoeae of other congeneric species from western Panama. Characters of the first zoeae of both species most closely agree with those Osawa's (2002) Group 4 of larvae.

The rate of metabolism in marine animals: environmental constraints, ecological demands and energetic opportunities

The rates of metabolism in animals vary tremendously throughout the biosphere. The origins of this variation are a matter of active debate with some scientists highlighting the importance of anatomical or environmental constraints, while others emphasize the diversity of ecological roles that organisms play and the associated energy demands. Here, we analyse metabolic rates in diverse marine taxa, with special emphasis on patterns of metabolic rate across a depth gradient, in an effort to understand the extent and underlying causes of variation. The conclusion from this analysis is that low rates of metabolism, in the deep sea and elsewhere, do not result from resource (e.g. food or oxygen) limitation or from temperature or pressure constraint. While metabolic rates do decline strongly with depth in several important animal groups, for others metabolism in abyssal species proceeds as fast as in ecologically similar shallow-water species at equivalent temperatures. Rather, high metabolic demand follows strong selection for locomotory capacity among visual predators inhabiting well-lit oceanic waters. Relaxation of this selection where visual predation is limited provides an opportunity for reduced energy expenditure. Large-scale metabolic variation in the ocean results from interspecific differences in ecological energy demand.

Indications of competition between non-indigenous round goby and native flounder in the Baltic Sea

Abstract Karlson, A. M. L., Almqvist, G., Skóra, K. E., and Appelberg, M. 2007. Indications of competition between non-indigenous round goby and native flounder in the Baltic Sea. – ICES Journal of Marine Science, 64: 479–486. The Ponto-Caspian round goby (Neogobius melanostomus) was introduced to the Gulf of Gdańsk, southern Baltic Sea, in the late 1980s, and it has now become the dominant demersal fish species in shallow water. This study aimed to assess diet preferences and the degree of diet overlap between the round goby and the native flounder (Platichthys flesus). Results from time-series of stomach contents and stable isotope analyses of wild-caught fish, together with prey preference experiments carried out in the laboratory, showed that the two species consumed similar species and sizes of prey. The similarities in diet suggest potential for food competition. Catch data showed both reverse depth distributions of round goby and flounder when round gobies were abundant and that the abundances of the two species were negatively correlated. The diet overlap between small flounders and round gobies was greatest when goby abundance was least, suggesting that abundance of round gobies may restrict flounder habitat utilization and, therefore, also food availability to the latter. Therefore, round gobies may have a negative influence on the commercially important flounder.

Morphological and reproductive acclimations to growth of two charophyte species in shallow and deep water

We investigated the distribution of two charophyte species, Chara fibrosa var. fibrosa (A. Br.) and Nitella hyalina (DC.) Ag., in Myall Lake, a shallow lake in New South Wales, Australia, in an attempt to elucidate the factors causing their distribution patterns. The field study was carried out from July 2003 to May 2005 and charophytes were sampled together with bottom sediments at 20 sampling locations in the lake on 13 occasions. Charophyte biomass (0–321 g DW m −2) displayed an optimum curve with depth and maximum biomass occurred between 1 and 2.5 m depth. In deeper water, shoots were longer (i.e., around 30 cm at 1 m depth to 60–90 cm between 2 and 4 m depth). Oospore and antheridia densities were higher in shallower water with a maximum around 80 cm. Plants growing in shallow depths had shorter internodes implying a short life cycle of shoots, and nodal spacing was relatively regular in contrast to its deep water counterparts although spacing tended to increase at locations farther from the apex. The present study also reports that there is an apparent decline in sexual propagule production rates with increasing water depth, further highlighting the different morphological and reproductive acclimations of charophytes in shallow and deep water.

A comparison of absorption and assimilation efficiencies between four species of shallow- and deep-living fishes

We captured two species of deep-sea zoarcids, Melanostigma pammelas and Lycodapus mandibularis, from Monterey Bay California and maintained them in the laboratory. One shallow-water zoarcid, Eucryphycus californicus, and an ecologically and morphologically similar stichaeid fish Xiphister atropurpureus were collected from intertidal and subtidal habitats in Monterey Bay. We investigated the absorption and assimilation efficiencies of these fishes to determine whether deep-sea species have evolved mechanisms to increase their efficiency of food use. Fishes were placed in experimental chambers and fed a known quantity of food. Ammonia excretion was measured and feces were collected daily. Both food and feces were analyzed for water, protein, lipid and ash to determine specific absorption efficiencies. Absorption ranged from 87.7 to 92.4% and assimilation efficiencies from 84.0 to 86.5%. Meal sizes from 0.5 to 4.0% of body weight did not affect the results. No significant differences were found between deep-sea and shallow-water species fed single meals or fed ad libitum for 10 days. This suggests that the selective pressure to maximize absorption and assimilation is universal and is not affected by the productivity of the habitat occupied. However, the relative size of the intestine in the deep-sea species was significantly smaller suggesting that they had a lower metabolic cost to maintain their digestive apparatus. It could not be concluded whether this was the result of pressure to conserve energy or rather the tendency of the shallow-living species to ingest more refractory material (i.e. sediment, algae).

Community structure of coral reef fishes in El Quadim Bay (El Quseir, Egyptian Red Sea coast)

This study investigates the community structure of fishes on the coral reef in El Quadim Bay, in order to obtain baseline data for a regular monitoring programme. A total of 16,683 fishes, representing 111 shallow-water species belonging to 47 genera and 31 families, was counted at 12 transects. Multivariate analysis indicates significant differences between the fish communities of the left side and right side of bay, as well as at different depths. This might be due to different exposure to wave action. The fish community in El Quadim Bay is very similar to those in undisturbed reefs and marine reserves in the Red Sea.

Dioxin compounds in the deep-sea rose shrimp Aristeus antennatus (Risso, 1816) throughout the Mediterranean Sea

Polychlorodibenzo- p-dioxins (PCDDs) and polychlorodibenzofurans (PCDFs) are among the more toxic anthropogenic contaminants. They are fat-soluble and accumulate in animal tissues. Exposure to PCDD/Fs can cause several endocrine, reproductive and developmental problems in animals, including human beings. Several studies have demonstrated that fish and invertebrates living in association with sediments are exposed to and accumulate contaminants, but to date there have been no studies of PCDD/Fs contamination in deep-sea regions. Specimens of Aristeus antennatus (Risso, 1816) were collected from depths of 600–2500 m at different points in the Mediterranean Sea, from the western basin off the coast of Barcelona to the central basin off the Peloponnesian Peninsula, with otter trawl gear. Amounts of PCDD/Fs were measured in different animal tissues by high resolution gas chromatography coupled to high resolution mass spectrometry (HRGC–HRMS). This is the first study to report the presence of PCDD/Fs in deep-sea organisms dwelling at depths below 600 m. A. antennatus presented levels of PCDD/Fs of the same order of magnitude, or slightly higher, as those found in shallow-water species ( Melicertus kerathurus) with respect to land-generated contamination. This highlights the widespread distribution of these pollutants and the potential threat posed to the biodiversity of fragile and vulnerable ecosystems such as the deep-sea. PCDD/F levels detected in the edible parts (muscle) of the commercial shrimp A. antennatus were clearly below the toxic limit value established by European legislation. Levels followed the trend muscle<ovary<hepatopancreas, according to the lipid content of the organs in question. The specific profile of toxic PCDD/F congeners in the studied Penaeid shrimp specimens was characterized mainly by octachlorodibenzo- p-dioxin (OCDD), 2,3,7,8-tetrachlorodibenzofuran (TCDF) and 2,3,4,7,8-pentachlorodibenzofuran (PeCDF) congeners. Moreover, non 2,3,7,8-substituted congeners bioaccumulated in this species, as observed in shallow-water crustaceans. PCDD/Fs were found in the shrimp A. antennatus throughout the Mediterranean Sea. Total PCDD/Fs burdens were higher in shrimps caught in the western Mediterranean than in those caught at eastern Mediterranean sites. There was a tendency for higher levels of PCDD/F contamination in samples obtained from deeper (2500 m) than from shallower sites (600 m).

Highly predictable photosynthetic production in natural macroalgal communities from incoming and absorbed light

Photosynthesis-irradiance relationships of macroalgal communities and thalli of dominant species in shallow coastal Danish waters were measured over a full year to test how well community production can be predicted from environmental (incident irradiance and temperature) and community variables (canopy absorptance, species number and thallus metabolism). Detached thalli of dominant species performed optimally at different times of the year, but showed no general seasonal changes in photosynthetic features. Production capacity of communities at high light varied only 1.8-fold over the year and was unrelated to incident irradiance, temperature and mean thallus photosynthesis, while community absorptance was a highly significant predictor. Actual rates of community photosynthesis were closely related to incident and absorbed irradiance alone. Community absorptance in turn was correlated to canopy height and species richness. The close relationship of community photosynthesis to irradiance is due to the fact that (1) large differences in thallus photosynthesis of individual species are averaged out in communities composed of several species, (2) seasonal replacement of species keeps communities metabolically active, and (3) maximum possible absorptance at 100% constrains the total photosynthesis of all species. Our results imply that the photosynthetic production of macroalgal communities is more predictable than their complex and dynamic nature suggest and that predictions are possible over wide spatial scales in coastal waters by measurements of vegetation cover, incoming irradiance and canopy absorptance.

A review of the genus Tryphosella (Crustacea: Amphipoda) from Britain and Ireland, with the description of a new species Tryphosella lowryi

A review of the shallow-water species of the genus Tryphosella from the British Isles is presented and a new species, Tryphosella lowryi, is described. In addition, Tryphosella minima is recorded from this region for the first time. This brings to five the total number of species of this genus now known from the British Isles. All taxa are fully described and illustrated, and a key to the species is provided.

Perfluorinated Contaminants in Sediments and Aquatic Organisms Collected from Shallow Water and Tidal Flat Areas of the Ariake Sea, Japan: Environmental Fate of Perfluorooctane Sulfonate in Aquatic Ecosystems

Perfluorinated compounds (PFCs), such as perfluorooctane sulfonate (PFOS), perfluorooctanoate (PFOA), perfluorononanoate (PFNA), perfluorohexane sulfonate (PFHS), and perfluorooctane sulfonamide (PFOSA) are widely distributed in aquatic ecosystems. Despite studies reporting the occurrence of PFCs in aquatic organisms, the fate of PFCs in tidal flat and marine coastal ecosystems is not known. In this study, we determined concentrations of PFOS, PFOA, PFNA, PFHS, and PFOSA in sediments; benthic organisms, including lugworm, mussel, crab, clam, oyster, and mudskipper fish from tidal flat; and shallow water species, such as filefish, bream, flounder, shark, finless porpoise, gull, and mallard collected from the Ariake Sea, Japan. PFOS and PFOA were detected in most of the samples analyzed, followed by PFNA, PFOSA, and PFHS. In shallow water species, PFOS was the dominant contaminant, and elevated concentrations were found in higher trophic level species, such as marine mammals and omnivorous birds. These results suggest biomagnification of PFOS through the coastal food chain. In contrast, PFOA was the most abundant compound in tidal flat organisms and sediments. PFOA concentrations in sediments, lugworms, and omnivorous mudskippers in tidal flat were approximately 1 order of magnitude greater than the levels of PFOS. This indicates differences in exposure pattern and bioavailability of PFOS and PFOA between shallow water and tidal flat organisms. The accumulation profiles of PFCs were compared with those of organochlorines (polychlorinated biphenyls, PCB), organotin (tributyltin,TBT), and polycyclic aromatic hydrocarbons (PAHs) in tidal flat and shallow water samples collected from the Ariake Sea. Concentrations of PFCs in sediments and in tidal flat organisms were significantly lower than that found for PCBs, TBT, and PAHs. Nevertheless, PFOS concentrations in shallow water species were comparable to and/or significantly greater than those of other classes of contaminants. This implies that the aqueous phase is a major sink for PFCs, which is different from what was observed for nonpolar organic pollutants.

Neverita delessertiana (Récluz in Chenu, 1843): a naticid species (Gastropoda: Caenogastropoda) distinct from Neverita duplicata (Say, 1822) based on molecular data, morphological characters, and geographical distribution

The members of the caenogastropod family Naticidae show highly conserved morphological characters, which in many cases complicate species separation. In such cases DNA sequence analysis may help to distinguish between species. In this work partial sequences from the small mitochondrial ribosomal RNA (16S rRNA) gene, the small nuclear ribosomal RNA (18S rRNA) gene, a short intron of the nuclear calmodulin (Cal) gene, and the mitochondrial cytochrome oxidase subunit I (COI) gene are shown to differ significantly between the genomes of what generally had been considered to be merely two morphological variants of the common Western Atlantic naticid Neverita duplicata (Say, 1822). Sequence differences between the two forms of Neverita duplicata are similar to differences between either of these two forms and the Eastern Pacific Neverita reclusiana (Deshayes, 1839), the Indopacific Neverita didyma (Röding, 1798), and the Mediterranean Neverita josephinia (Risso, 1826). The COI sequences divergence between the two forms of Neverita duplicata is in the range of the average COI sequences divergence reported for congeneric species of Mollusca (Hebert 2003). We conclude that in addition to Neverita duplicata a second shallow water species of Neverita exists along the US Atlantic and Gulf coasts for which the name Neverita delessertiana (Récluz, 1843) is available.

Neverita delessertiana (Récluz in Chenu, 1843): a naticid species (Gastropoda: Caenogastropoda) distinct from Neverita duplicata (Say, 1822) based on molecular data, morphological characters, and geographical distribution

The members of the caenogastropod family Naticidae show highly conserved morphological characters, which in many cases complicate species separation. In such cases DNA sequence analysis may help to distinguish between species. In this work partial sequences from the small mitochondrial ribosomal RNA (16S rRNA) gene, the small nuclear ribosomal RNA (18S rRNA) gene, a short intron of the nuclear calmodulin (Cal) gene, and the mitochondrial cytochrome oxidase subunit I (COI) gene are shown to differ significantly between the genomes of what generally had been considered to be merely two morphological variants of the common Western Atlantic naticid Neverita duplicata (Say, 1822). Sequence differences between the two forms of Neverita duplicata are similar to differences between either of these two forms and the Eastern Pacific Neverita reclusiana (Deshayes, 1839), the Indopacific Neverita didyma (Roding, 1798), and the Mediterranean Neverita josephinia (Risso, 1826). The COI sequences divergence between the two forms of Neverita duplicata is in the range of the average COI sequences divergence reported for congeneric species of Mollusca (Hebert 2003). We conclude that in addition to Neverita duplicata a second shallow water species of Neverita exists along the US Atlantic and Gulf coasts for which the name Neverita delessertiana (Recluz, 1843) is available.

Interactive effects of temperature and nutritional condition on the energy budgets of the sea urchins Arbacia punctulata and Lytechinus variegatus (Echinodermata: Echinoidea)

Arbacia punctulata and Lytechinus variegatus are widely distributed echinoid species in shallow water in the western Atlantic Ocean, Caribbean Sea and Gulf of Mexico that seem to have different life history strategies. We evaluated the effect of two types of stress (high temperature and starvation) on gonad production and scope for growth. We hypothesized that A. punctulata has a stress tolerant life strategy and would be more tolerant to stress and L. variegatus has a competitive–ruderal strategy and would be less tolerant to stress. Gonad production by A. punctulata was not as greatly affected by temperature as L. variegatus, suggesting the hypothesis was correct. Arbacia punctulata had a significantly higher excretion rate indicating greater energy allocation to maintenance than production. Lytechinus variegatus had a significantly greater consumption rate but did not absorb significantly more energy. Arbacia punctulata compensated for its lower food consumption by a higher absorption efficiency. Measured energy expenditure and calculated scope for growth did not differ. However, the percentage change in energy absorbed and energy expenditure was greater for L. variegatus than for A. punctulata with a change in temperature. Feeding had a greater effect on production than temperature suggesting that the biotic stress of low food availability is more important than an abiotic stress such as temperature on energy budgets.

Temperature and pressure tolerance of embryos and larvae of the Atlantic seastars Asterias rubens and Marthasterias glacialis (Echinodermata: Asteroidea): potential for deep-sea invasion

Eggs of the shallow-water asteroids Asterias rubens and Marthasterias glacialis were fertilized in vitro and incubated through the early embryonic cleavages until the larval stage. Early embryos, blastulae, gastrulae, and swimming bipinnaria were subjected to a temperature/pressure matrix of 5, 10, 15 and 20°C and 1, 50, 100, 150 and 200 atm. Early embryos of both species were able to tolerate pressures up to 150 atm at 15°C and 100 atm at 10°C. Survivorship of A. rubens swimming bipinnaria remained high (>70%) after incubation at all the temperature/pressure combinations. Swimming larvae ranged from 100% survival at 10°C/50 atm to 72% at 15°C/200 atm. For M. glacialis the highest survival of swimming larvae was 100% at 5, 15 and 20°C/1 atm and 15 and 20°C/50 atm, but decreased to 56.85% at 5°C/200 atm. In general, survivorship decreased as pres- sure increased; nevertheless larvae generally tolerated pressures of 200 atm. Data for the tempera- ture and pressure effects on the later stages of development suggest that all the larval stages are more temperature/pressure tolerant than the early embryos and survivorship increases with larval age. All the developmental stages of both species have a potentially wider depth distribution than their respective adults. Therefore, the larvae of shallow-water species A. rubens and M. glacialis could survive transport to deeper waters and may be capable of acting as colonists in the deep sea.

Wind turbine underwater noise and marine mammals: implications of current knowledge and data needs

The demand for renewable energy has led to construction of offshore wind farms with high-power turbines, and many more wind farms are being planned for the shallow waters of the world's marine habitats. The growth of offshore wind farms has raised concerns about their impact on the marine environment. Marine mammals use sound for foraging, orientation and communication and are therefore possibly susceptible to negative effects of man-made noise generated from con- structing and operating large offshore wind turbines. This paper reviews the existing literature and assesses zones of impact from different noise-generating activities in conjunction with wind farms on 4 representative shallow-water species of marine mammals. Construction involves many types of activities that can generate high sound pressure levels, and pile-driving seems to be the noisiest of all. Both the literature and modeling show that pile-driving and other activities that generate intense impulses during construction are likely to disrupt the behavior of marine mammals at ranges of many kilometers, and that these activities have the potential to induce hearing impairment at close range. The reported noise levels from operating wind turbines are low, and are unlikely to impair hearing in marine mammals. The impact zones for marine mammals from operating wind turbines depend on the low-frequency hearing-abilities of the species in question, on sound-propagation conditions, and on the presence of other noise sources such as shipping. The noise impact on marine mammals is more severe during the construction of wind farms than during their operation.

Raspailia (Raspaxilla) bouryesnaultae, a new name for Brazilian Raspaxilla elegans Boury-Esnault, 1973 (Demospongiae, Poecilosclerida, Raspailiidae) with a redescription and a new record

The combination Raspailia (Raspaxilla) elegans sensu Boury-Esnault, 1973 is precoccupied by Raspailia elegans Lendenfeld,1887 (Porifera, Poecilosclerida, Raspailiidae). A new name for this Brazilian shallow-water species is proposed, Raspailia (Raspaxilla) bouryesnaultae n.n., and the species is redescribed based on a skeleton slide from the holotype and additional material freshly collected from the coast of Santa Catarina state. The distribution is now expanded to encompass the area from 22º to 27°S, in southeastern Brazil.

Susceptibility of zoospores to UV radiation determines upper depth distribution limit of Arctic kelps: evidence through field experiments

Summary 1 The UV susceptibility of zoospores of the brown seaweeds Saccorhiza dermatodea, Alaria esculenta and Laminaria digitata (Laminariales) was determined in field experiments in June 2004 on Spitsbergen (78°55′ N, 11°56′ E). 2 Freshly released zoospores were exposed for 1 or 2 days at various water depths to ambient solar radiation, ambient solar radiation depleted of UVB radiation (UVBR) and ambient solar radiation depleted of both UVBR and UVAR. Subsequently, germination rates were determined after exposure to favourable light and temperature conditions in the laboratory. 3 The radiation regime was monitored at the water surface and in the water column using data loggers attached adjacent to each experimental platform for the duration of the field exposure. 4 Under ambient solar radiation, the tolerance of zoospores to UVR was highest in the shallow water species S. dermatodea, intermediate in the upper to mid sublittoral A. esculenta and lowest in the upper to mid sublittoral L. digitata. There was, however, no difference in the susceptibility of the zoospores to ambient solar radiation or to solar radiation depleted of UVBR. 5 The water column was relatively UV transparent, especially in the upper water layers. The 1% UVB depth ranged between 5.35 and 6.87 m, although on one stormy day the 1% UVB depth was only 3.57 m, indicating resuspension of sediments. 6 Early developmental stages are most susceptible to environmental stress. Tolerance of zoospores to UVR is a major if not one of the most important factors determining the upper distribution limit of different Laminariales on the shore. 7 Kelps are very important primary producers in inshore coastal ecosystems, serving as food for herbivores and as habitat for many organisms. Enhanced UVBR due to stratospheric ozone depletion may lead to changes in the depth distribution of kelps and may cause significant ecological domino effects.

Cirripedia of Madeira

We give a list of Cirripedia from Madeira Island and nearby deep water, based on specimens in the collection of the Museu Municipal do Funchal (História Natural) (MMF), records mentioned in the literature, and recent collections. Tesseropora atlantica Newman and Ross, 1976 is recorded from Madeira for the first time. The Megabalanus of Madeira is M. azoricus. There are 20 genera containing 27 species, of which 22 occur in depths less than 200 m. Of these shallow water species, eight are wide-ranging oceanic forms that attach to other organisms or to floating objects, leaving just 13 truly benthic shallow water barnacles. This low diversity is probably a consequence of the distance from the continental coasts and the small area of the available habitat. No endemic species have been found.