Journal of Marine Biology The latest articles from Hindawi Publishing Corporation © 2014 , Hindawi Publishing Corporation . All rights reserved. The First Molecular Characterization of Picocyanobacteria from the Argentine Sea Thu, 20 Nov 2014 00:00:00 +0000 Picocyanobacteria are abundant throughout the world’s oceans. Particularly, it has been reported that Synechococcus strains have a wide latitudinal distribution, from polar to tropical waters. However, their molecular characterization in the Southwest Atlantic Ocean is still missing. We analyzed Synechococcus genetic diversity in a sector of the Argentine Sea, one of the richest biological areas of the world oceans. 16S rRNA amplicons obtained after PCR amplification of environmental DNA extracted from water samples of this area were used for DGGE and sequenced. Only Synechococcus sequences could be retrieved. On the other hand, we isolated two Synechococcus strains from the environment. Our analyses revealed that the clade I group was widespread from latitude 38°S to 48°S and that can coexist with clade IV strains in shelf waters. The cooccurrence of these two clades may be related to an adaptation to high-nutrient/low-temperature waters. Our data are the first report on Synechococcus ecotypes that would be important contributors to phytoplankton biomass in the Argentine Sea, one of the richest biological areas of the world oceans. Macarena Perez-Cenci, Gonzalo F. Caló, Ricardo I. Silva, Rubén M. Negri, and Graciela L. Salerno Copyright © 2014 Macarena Perez-Cenci et al. All rights reserved. Abundance and Diversity of Holothuroids in Shallow Habitats of the Northern Red Sea Thu, 13 Nov 2014 08:33:44 +0000 Holothuroid sea cucumbers are vital members of Coral Reefs and associated marine habitats and provide vital ecological services. In the southern regions of the Red Sea their populations have been decimated by overfishing. The main objective of this study was to test the hypothesis that the northern part of the Red Sea serves as an ecological refuge for the species threatened farther to the south. Accordingly, populations of sea cucumbers in 4 shallow sites south of Eilat, Israel (29°33′00N 34°57′14E), were repeatedly surveyed from November 2013 to April 2014. Overall 11 species were observed in these shallow sites. Their abundance and diversity differed significantly between sites, but not temporally. In sites in marine protected areas, with an intact fringing reef, diversity was high, with Holothuria edulis and Bohadschia sp. being the most common species. In areas with higher human use and characterized by rubble and scattered corals, diversity was low, and Actinopyga bannwarthi was the most common species. The observed abundance and diversity did not support the refuge hypothesis. These findings are discussed in relation to other surveys of abundance and diversity in similar habitats. Boaz Yuval, Lee Sudai, and Yarden Ziv Copyright © 2014 Boaz Yuval et al. All rights reserved. Cetacean Presence in the Trincomalee Bay and Adjacent Waters, Sri Lanka Tue, 21 Oct 2014 07:30:52 +0000 In Sri Lanka thirty species of cetaceans have been recorded to date. The canyon at Trincomalee bay is a multiple submarine canyon complex and anecdotal reports suggest that the Trincomalee bay and its adjacent waters are utilised by a number of cetacean species. Though Cetaceans are known to be abundant in the waters off Trincomalee there is a dearth of research and data pertaining to the abundance and species frequenting the Trincomalee bay and its adjacent waters. As such the current study was initiated, to get a consensus of the abundance and occurrences of species in Trincomalee Bay and its adjacent waters. Field surveys were carried out for 19 months and the research platform was a 35-foot commercial fishing vessel. 177 cetacean encounters were recorded on 67 of the 75 field days. Remarkably a total of 11 species of cetaceans which composed of two species of Baleen Whales and nine species of Toothed Whales were recorded. Delphinidae was the most common family recorded, followed by Balaenopteridae, Ziphiidae, Physeteridae, and Kogiidae. Spinner Dolphins were the most abundant cetacean owing to the large pods observed and the regularity of the sightings. They were the only species seen feeding/traveling with birds and fish (tuna). Sperm Whales, Blue Whales, and Bryde’s Whales were also relatively common. Two records of interspecific association between cetaceans were recorded. The increase in the human population in the study area has resulted in the overexploitation of marine resources which has dire repercussions on the marine mammal communities found in these waters. Ranil P. Nanayakkara, Jayampathi Herath, and Ruvinda K. de Mel Copyright © 2014 Ranil P. Nanayakkara et al. All rights reserved. Development of Enzymes and In Vitro Digestibility during Metamorphosis and Molting of Blue Swimming Crab (Portunus pelagicus) Wed, 08 Oct 2014 09:24:15 +0000 The work focuses on development of digestive enzymes (amylase, total protease, trypsin, and chymotrypsin) and activity ratio of trypsin to chymotrypsin (T/C ratio) for digestive efficiency and growth, in blue swimming crab (Portunus pelagicus) during metamorphosis and molting. Specific activities of all enzyme parameters studied were associated with growth during metamorphosis, while only those of trypsin and T/C ratio were associated during molting cycle where trypsin and chymotrypsin specific activities associated with consumption rate with especially high levels during late intermolt and early premolt stages. About 50% increased weight gain was observed with at least double increased T/C ratio at the end of molting period, compared to the stages prior to molting. Growth of carapace would be more significant after finishing molting. Carapace width gain and T/C ratio were highest at the first crab stage. Studies of in vitro protein digestibility of different feed raw materials indicated that Artemia, Rotifer, and Moina are the best for larval stages. Otherwise, the use of shrimp feed and Artemia flake could be the alternatives. Incorporating of cassava meal into the feed formula for early adult stage (juvenile) could be an advantage. The proteins from animals are more beneficial for adult crab culture than the proteins from plants and bacteria. The digestible quality of dietary protein is very important during larval stages, while the protein level of diet is more important during adult stages with fully developed digestive enzymes. Phanu Chamchuen, Boonyarath Pratoomchat, Arunee Engkakul, Uthaiwan Kovitvadhi, and Krisna Rungruangsak-Torrissen Copyright © 2014 Phanu Chamchuen et al. All rights reserved. Harvesting Model for Fishery Resource with Reserve Area and Bird Predator Mon, 22 Sep 2014 09:14:01 +0000 The aim of this paper is to study the dynamics of fishery resource with reserve area in the presence of bird predator. The aquatic region under investigation is divided into two zones: one free for fishing and another restricted for any kind of fishery. The criteria of biological and bionomic equilibrium of system are established. The points of local stability, global stability, and instability are obtained for the proposed model. An optimal harvesting policy is established using Pontryagin’s maximum principle. At last the theoretical results obtained are illustrated with the help of numerical simulation. Amit Sharma and Bhanu Gupta Copyright © 2014 Amit Sharma and Bhanu Gupta. All rights reserved. Locomotion and Functional Spine Morphology of the Heart Urchin Brisaster fragilis, with Comparisons to B. latifrons Mon, 22 Sep 2014 06:57:54 +0000 The heart urchin Brisaster fragilis is an important bioturbator found in the Estuary and Gulf of St. Lawrence. Several adaptations allow it to move within fine sediments (e.g., test shape, spine morphology, and distribution), which are compared here to those of its Pacific sibling species B. latifrons. While ventral spatulate spines and dorsal and anterolateral curvilinear spines are similar between the two species, anterior spines differ significantly: sigmoid-shaped for B. fragilis and curvilinear for B. latifrons. This morphological difference, in addition to a narrower plastron for B. fragilis, suggests a different digging strategy. In situ video observations of B. fragilis show a “dig and move” strategy: anterior spines “dig” forward at the sediment while the plastron spines “move” the urchin into the newly created space. B. latifrons on the other hand uses an oblique rocking motion. This suggests that generalizations derived from one or few species displaying similar body shapes may not be possible. Factors such as sediment depth (i.e., the amount of sediment above the urchin) are likely to affect movement and force the animal to employ a different digging strategy, even within a single species. The role of spines for locomotion is further discussed, with additional reference to tubercle morphology. Danielle E. Walker and Jean-Marc Gagnon Copyright © 2014 Danielle E. Walker and Jean-Marc Gagnon. All rights reserved. Dynamic Changes in Bacterial Population and Corresponding Exoenzyme Activity in Response to a Tropical Phytoplankton Bloom Chattonella marina Sun, 21 Sep 2014 08:31:18 +0000 The raphidophyte Chattonella marina (Subrahmanyan) Hara & Chihara bloom which causes lethal effects on marine ecosystem has been reported intermittently from Indian waters. In the present study, periodic samplings were made in a Chattonella marina bloom area, off Mahe, on 27 and 29 October and 1 November 2011 (in different phases of the bloom) to assess the associated bacterial population and their exoenzyme activity. Microbial community composition of Chattonella marina bloom revealed a twentyfold increase in bacterial load over the nonbloom area. The bacterial genera, Micrococcus, Flavobacterium, Vibrio, and Pseudomonas, increased significantly during the declining phase of the bloom. An assessment of the extracellular enzyme production also showed a marked increase in percentage of bacterial strains, potent in protease production, suggesting the possible role of proteolytic bacteria in bloom crash. This study reveals the bacterial community succession during the bloom and indicates that bacteria play an important role in bloom regulation. Anit M. Thomas, M. G. Sanilkumar, K. C. Vijayalakshmi, A. A. Mohamed Hatha, and A. V. Saramma Copyright © 2014 Anit M. Thomas et al. All rights reserved. Gametogenesis, Embryogenesis, and Fertilization Ecology of Platygyra acuta in Marginal Nonreefal Coral Communities in Hong Kong Mon, 08 Sep 2014 09:00:49 +0000 Understanding the reproductive biology of dominant coral species in subtropical nonreefal coral communities is critical in providing important information on the processes underlying the distribution limits of coral species and communities. This is the first study that investigates the reproduction cycle, gametogenesis, and fertilization ecology of Platygyra acuta. Results indicated that P. acuta is hermaphroditic and exhibits a single annual gametogenic cycle. Oogenic and spermatogenic cycle occurs for 6-7 months and for 2 months, respectively, prior to annual mass spawning event in May to June in Hong Kong. It took 18 hours for P. acuta to complete embryonic development, develop cilia, and start to rotate. High (>70%) fertilization success can be achieved under a broad range of sperm concentrations from 104 to 107 sperms mL−1. Fertilization success remained consistently high 6 h after spawning, indicating a prolonged viability of its gametes that is much longer than that recorded for other coral species. Significantly higher percentage of fertilization success was recorded in the first of the two consecutive nights of spawning, suggesting differences in the quality of the eggs and/or sperms between days of spawning. These results serve as important baseline information for better understanding of corals in marginal communities. Apple Pui Yi Chui, Man Chung Wong, Siu Hong Liu, Ga Wun Lee, Sze Wai Chan, Pui Ling Lau, Sin Man Leung, and Put Ang Jr. Copyright © 2014 Apple Pui Yi Chui et al. All rights reserved. Ecological Significance of the Association between Stomopneustes variolaris (Echinoidea) and Lumbrineris latreilli (Polychaeta) from Visakhapatnam Coast, India Thu, 14 Aug 2014 07:29:17 +0000 The present study reports a new association between the sea urchin Stomopneustes variolaris (Lamarck, 1816) and the polychaete Lumbrineris latreilli (Audouin & Milne Edwards, 1834) based on the specimens collected intertidally at Bay of Bengal (Visakhapatnam, east coast of India). Out of 60 sea urchins collected, 10 (16.67%) were associated with the polychaete. The prevalence increased with the increasing sea urchin test diameter. All polychaetes were exclusively found between the spines, in the aboral region of the host. This association protects the polychaete from the predators during displacement from its natural habitat. Archana Ayyagari and Ramesh Babu Kondamudi Copyright © 2014 Archana Ayyagari and Ramesh Babu Kondamudi. All rights reserved. Variability in the Structure of Phytoplankton Assemblages in relation to Human Disturbance in Southern Coast of Tunisia Wed, 25 Jun 2014 00:00:00 +0000 We investigated the impact of industrial effluents on phytoplankton assemblage in southern Tunisia (Skhira). We specifically addressed changes in microalgae composition caused by this anthropogenic interference. A hierarchical sampling design was used to compare planktonic microalgae structure between one disturbed station and one control station. Samples were collected by scuba diving at 5 m depth in August 2012. A total of 76 microalgae taxa were identified. Dinoflagellates abundance was low in the disturbed station, especially Gonyaulacales and Prorocentrales due to P-limitation, whereas diatoms and cyanobacteria abundance were low in control station which is characterized by Si-limitation. Lotfi Mabrouk, Lamia Dammak, Asma Hamza, Mabrouka Mahfoudhi, and Med-Najmeddine Bradai Copyright © 2014 Lotfi Mabrouk et al. All rights reserved. A Comparison of Abundance and Diversity of Epiphytic Microalgal Assemblages on the Leaves of the Seagrasses Posidonia oceanica (L.) and Cymodocea nodosa (Ucria) Asch in Eastern Tunisia Tue, 03 Jun 2014 00:00:00 +0000 We studied spatial patterns in assemblages of epiphytic microalgae on the leaves of two seagrass species with different morphologies and longevity, Cymodocea nodosa and Posidonia oceanica, which cooccur in Chebba in Eastern Tunisia. Epiphyte assemblages were described for each species in summer. Epiphyte microalgal assemblages were more abundant on the leaves of C. nodosa but more diversified on the leaves of P. oceanica. We suggest that the differences in species composition and abundance between those seagrass species may reflect an interaction of timescales of seagrass longevity with timescales of algal reproductive biology. Short-lived C. nodosa was dominated by fast growing species such as the cyanobacteria species Oscillatoria sp., while P. oceanica leaves were colonized by more mature and diversified species such as Prorocentrales. Local environmental conditions (hydrodynamics, light penetration), host characteristics (meadow type, shapes forms of leaves, life span, and growth rate), and grazing effect seem also to be responsible for these dissimilarities in epiphytic microalgae communities. Lotfi Mabrouk, Mounir Ben Brahim, Asma Hamza, Mabrouka Mahfoudhi, and Med Najmeddine Bradai Copyright © 2014 Lotfi Mabrouk et al. All rights reserved. Covarying Shell Growth Parameters and the Regulation of Shell Shape in Marine Bivalves: A Case Study on Tellinoidea Thu, 29 May 2014 13:16:21 +0000 Specific parameters characterising shell shape may arguably have a significant role in the adaptation of bivalve molluscs to their particular environments. Yet, such functionally relevant shape parameters (shell outline elongation, dissymmetry, and ventral convexity) are not those parameters that the animal may directly control. Rather than shell shape, the animal regulates shell growth. Accordingly, an alternative, growth-based description of shell-shape is best fitted to understand how the animal may control the achieved shell shape. The key point is, in practice, to bring out the link between those two alternative modes of shell-shape descriptions, that is, to derive the set of equations which connects the growth-based shell-shape parameters to the functionally relevant shell-shape parameters. Thus, a preliminary object of this note is to derive this set of equations as a tool for further investigations. A second object of this work is to provide an illustrative example of implementation of this tool. I report on an unexpected negative covariance between growth-based parameters and show how this covariance results in a severe limitation of the range of interspecific variability of the degree of ventral convexity of the shell outline within the superfamily Tellinoidea. Hypotheses are proposed regarding the constraints possibly at the origin of this limitation of interspecific variability. Jean Béguinot Copyright © 2014 Jean Béguinot. All rights reserved. Metabolic Effects in the Bivalve Perna perna and Mytilus galloprovincialis: Impact on the Environment due to Contamination by Copper Tue, 20 May 2014 11:26:59 +0000 This work presents the study of the effects of acute exposure to various concentrations of copper from 0.03 to 0.59 μmol·L−1 on the metabolic activities (nitrogen and phosphorus), protein levels, catalase (CAT) enzyme activities, and the biological response malondialdehyde (MDA) in the mollusks Perna perna and Mytilus galloprovincialis. The concentrations above 0.88 μmol·L−1 have proven to be lethal to P. perna. The results show slight disturbances of metabolism as a result of pollutant and a significant correlation between metal contamination and ammonia nitrogen levels, resulting in an increase in the latter after 48 h of M. galloprovincialis exposure to 0.59 μmol·L−1 of copper concentrations. CAT was rapidly induced even by low concentrations of copper; MDA was increased only with low concentrations of copper in P. perna. Mohamed Brahim Errahmani, Fayza Zouaoui, and Djamel Bendjoudi Copyright © 2014 Mohamed Brahim Errahmani et al. All rights reserved. The Immune Response of Acanthaster planci to Oxbile Injections and Antibiotic Treatment Wed, 09 Apr 2014 08:40:37 +0000 Bile salts have been recently identified as a rapid and effective method for killing A. planci. However the mechanistic basis of this new control method is poorly understood. This study explored the immune response(s) of A. planci and/or pathogenesis resulting from the injection of bile salts. To account for the possible role of pathogenesis in causing high rates of mortality, A. planci was treated with antibiotics to minimise the incidence and severity of bacterial infections. No significant difference in the time to death between groups with and without antibiotic treatment was reported, suggesting a limited bacterial effect on the induction of disease and death of injected sea stars. The number of circulating coelomocytes increased significantly after injection confirming the induction of a strong immune response. Five types of circulating cells were identified: (1) phagocytes, (2) small hyaline cells, (3) colourless spherule cells, (4) red spherule cells, and (5) fusiform cells. Histological analysis of A. planci tissues showed that the mechanism leading to rapid mortality is related to necrosis and/or apoptosis, rather than transmissible disease. Therefore, bile salts are an effective and safe method for killing crown-of-thorns sea star in situ. Alexandra Grand, Morgan Pratchett, and Jairo Rivera-Posada Copyright © 2014 Alexandra Grand et al. All rights reserved. Variability in the Structure of Planktonic Microalgae Assemblages in Water Column Associated with Posidonia oceanica (L.) Bed in Tunisia Sun, 23 Mar 2014 16:16:15 +0000 Patterns of phytoplankton in areas with seagrass (Posidonia oceanica) and areas without seagrass were quantified in the coast of Chebba (East of Tunisia). Replicate samples were collected at August 2011, from four stations (separated by 500 of metres). The diversity of phytoplankton was high around P. oceanica meadows compared to area without seagrass. A possible explanation to this finding is that water motion and hydrodynamics forces cause leaves agitation allowing the passage of epiphytic species in the water column. Our results also show an increase of abundance of potentially toxic dinoflagellates around Posidonia bed such as Alexandrium minitum, Amphidinium carterae, Karenia selliformis, Coolia monatis, Karlodinium veneficum, Ostreopsis ovata, Prorocentrum concavum, P. minimum, P. rathymum, and P. lima. Installation of fish farms on Posidonia beds should be avoided, not only to preserve this vulnerable habitat, but also to avoid fish contamination by toxic species derived from the resuspension of epiphytic community on seagrass substrata to the water column. Lotfi Mabrouk, Asma Hamza, and Med-Najmeddine Bradai Copyright © 2014 Lotfi Mabrouk et al. All rights reserved. Plasma Vitellogenin in Free-Ranging Loggerhead Sea Turtles (Caretta caretta) of the Northwest Atlantic Ocean Thu, 27 Feb 2014 08:12:55 +0000 Vitellogenin is the egg yolk precursor protein produced by oviparous vertebrates. As endogenous estrogen increases during early reproductive activity, hepatic production of vitellogenin is induced and is assumed to be complete in female sea turtles before the first nesting event. Until the present study, innate production of vitellogenin has not been described in free-ranging sea turtles. Our study describes circulating concentrations of vitellogenin in loggerhead sea turtles (Caretta caretta) from the Northwest Atlantic Ocean. We collected blood samples from juveniles and adults via in-water captures off the coast of the Southeast USA from May to August, and from nesting females in June and July at Hutchinson Island, Florida. All samples were analyzed using an in-house ELISA developed specifically to measure Caretta caretta vitellogenin concentration. As expected, plasma vitellogenin declined in nesting turtles as the nesting season progressed, although it still remained relatively elevated at the end of the season. In addition, mean vitellogenin concentration in nesting turtles was 1,000 times greater than that measured in samples from in-water captures. Our results suggest that vitellogenesis may continue throughout the nesting season, albeit at a decreasing rate. Further, vitellogenin detected in turtles captured in-water may have resulted from exposure to endocrine disrupting chemicals. Kimberly Smelker, Lauren Smith, Michael Arendt, Jeffrey Schwenter, David Rostal, Kyle Selcer, and Roldán Valverde Copyright © 2014 Kimberly Smelker et al. All rights reserved. Shape of Aquatic Animals and Their Swimming Efficiency Tue, 25 Feb 2014 12:56:37 +0000 The best swimmers have a streamlined shape that ensures an attached flow pattern and a laminar boundary layer at rather large values of the Reynolds number. Simple expressions may be obtained for the volumetric drag coefficient of an ideal body of revolution under laminar unseparated flow conditions together with estimations of a critical value of the Reynolds number. A measure, the capacity-efficiency factor, calculated for different organisms and underwater vehicles, shows that information about animal shapes and locomotion is of utmost biological interest and could be useful to improve robot fish and underwater vehicles as well. I. Nesteruk, G. Passoni, and A. Redaelli Copyright © 2014 I. Nesteruk et al. All rights reserved. Studies on the Survival and Growth of Fry of Catla catla (Hamilton, 1922) Using Live Feed Tue, 25 Feb 2014 12:21:36 +0000 Effect of live feed on the survival and growth of fry of Catla catla using three different live feeds namely, Cyclopoid (Thermocyclops decipiens), Cladoceran (Moina micrura), and mixed diet (Cyclopoid and Cladoceran) were studied. Commercial feed (Sunder’s feed) was used as control. Feeding experiments were carried out in 100 L tanks for 40 days. Fish fry fed with the mixed diet showed significantly better survival rate (54.80 ± 2.43%) than those fed with other food types . Fish fry fed with Cyclopoid had significantly better growth (26.03 ± 1.88 mm, weight 61.07 ± 3.53 mg) than those fed with other food types. Biochemical studies showed higher level of protein, carbohydrate, and lipid content in Catla fry fed with Cyclopoid diet. The results are discussed in the light of the literature available. It could be suggested that the Cyclopoid diet can be used as live feed for effective production of Catla fry. Abdul Kadhar, Arun Kumar, Jawahar Ali, and Akbar John Copyright © 2014 Abdul Kadhar et al. All rights reserved. Identification of Fine-Scale Marine Benthic Ecoclines by Multiple Parallel Ordination Sun, 16 Feb 2014 12:42:39 +0000 The species-environment relationship is a fundamental structural property of natural ecosystems. Marine sedimentary macrofauna is known to be structured by a range of environmental variables; however, the mechanisms by which environmental variables covary to form complex-gradients (i.e., groups of intercorrelated environmental variables), and how these are related to coenoclines (i.e., gradients in species composition), remain poorly understood. We classified our study area into geomorphological features that were used for stratified sampling of macrofaunal polychaetes, molluscs, and echinoderms. The resulting species-by-site matrix was subjected to indirect gradient analysis by a multiple parallel ordination strategy, using detrended correspondence analysis and nonmetric multidimensional scaling. One major and one minor coenocline were identified. Based on the correlation between complex-gradients and the main coenocline we hypothesise the existence of two ecoclines that we have termed Periodic hypoxia and Periodic physical forcing. We conclude that a combination of recurrent (periodical) and extreme events is likely to determine the variation found in the species composition of marine sedimentary ecosystems. Based on the results of our study, we conclude that indirect gradient analysis is a useful tool for enhancement of our basic mechanistic understanding of the processes governing the compositional structure of marine sediment communities. Thijs Christiaan van Son, Rune Halvorsen, Karl Norling, Torgeir Bakke, Maria Kaurin, and Fredrik Melsom Copyright © 2014 Thijs Christiaan van Son et al. All rights reserved. Correcting Positional Errors in Shore-Based Theodolite Measurements of Animals at Sea Wed, 22 Jan 2014 09:58:07 +0000 Determining the position of animals at sea can be particularly difficult and yet, accurate range and position of animals at sea are essential to answer a wide range of biological questions. Shore-based theodolite techniques have been used in a number of studies to examine marine mammal movement patterns and habitat use, offering reliable position measurements. In this study we explored the accuracy of theodolite measurements by comparing positional information of the same objects using two independent techniques: a shore-based theodolite station and an onboard GPS over a range of 25 km from the shore-based station. The technique was developed to study the habitat use of sperm whales (Physeter macrocephalus) off Kaikoura, New Zealand. We observed that the position accuracy fell rapidly with an increase in range from the shore-based station. Results showed that the horizontal angle was accurately determined, but this was not the case for the vertical angle. We calibrated the position of objects at sea with a regression-based correction to fit the difference in distance between simultaneously recorded theodolite fixes and GPS positions. This approach revealed the necessity to calibrate theodolite measurements with objects at sea of known position. Ophélie Sagnol, Femke Reitsma, Christoph Richter, and Laurence H. Field Copyright © 2014 Ophélie Sagnol et al. All rights reserved. Estimating Otter Numbers Using Spraints: Is It Possible? Sun, 19 Jan 2014 00:00:00 +0000 Spraints have been used to survey otters in the UK since 1979 and a standard methodology has been set up which has been used in Britain and Europe for most survey work. At present data from these surveys is being used to give an estimation of actual population numbers. However, for this to be possible, there must be a correlation between sprainting numbers, active spraint sites, and otter numbers. This paper investigates whether such a correlation exists. There is evidence from previous work that there is seasonal variation in sprainting and this study confirms this. Therefore spraint surveys should be undertaken in the same months for each repeat survey. Paul Yoxon and Kirsty Yoxon Copyright © 2014 Paul Yoxon and Kirsty Yoxon. All rights reserved. Limpets and Their Algal Epibionts: Costs and Benefits of Acrosiphonia spp and Ulva lactuca Growth Thu, 09 Jan 2014 11:45:46 +0000 Epibiont and basibiont relationships can have positive and negative effects on both organisms involved, ranging in intensity from minor to major effects. Limpets of species Lottia pelta are commonly found with two algal species growing on their backs, Ulva lactuca and Acrosiphonia spp. Previous research has shown that basibionts (substrate organism) and epibionts (organism growing on the surface) have complex interactions that can be positive, negative, or neutral. A force transducer and flume were used to measure the drag forces experienced by a limpet at various water velocities. Presence of either epiphyte significantly increased limpet drag. Acrosiphonia produced a greater drag effect than U. lactuca, increasing the force substantially. When dropped in a tank, limpets with algal growth landed foot-down significantly more often than limpets without algal growth. Acrosiphonia spp. had a greater effect than Ulva lactuca. Lastly, limpets in a wind tunnel with algal growth (especially Acrosiphonia) had cooler body temperatures than limpets without algal growth. In conclusion, the effects on the basibiont of this relationship were found to be both positive and negative. Travis Seaborn Copyright © 2014 Travis Seaborn. All rights reserved. Bioagents and Commercial Algae Products as Integrated Biocide Treatments for Controlling Root Rot Diseases of Some Vegetables under Protected Cultivation System Thu, 12 Dec 2013 10:52:44 +0000 Integrated commercial blue-green algae extracts and bioagents treatments against vegetables root rot incidence when used as soil drench under greenhouse and plastic house conditions were evaluated. All applied treatments reduced significantly root rot incidence at both pre- and postemergence growth stages of cucumber, cantaloupe, tomato, and pepper plants compared with untreated check control. In pot experiment, the obtained results showed that treatments of Trichoderma harzianum or Bacillus subtilis either alone or combined with commercial algae extracts were significantly superior for reducing root rot disease for two tested vegetable plants compared with the other tested treatments as well as control. It is also observed that rising concentrations of either algae products, Oligo-X or Weed-Max, were reflected in more disease reduction. Promising treatments for controlling root rot disease incidence were applied under plastic houses conditions. As for field trails carried out under plastic houses conditions at different locations, the obtained results revealed that the applied combined treatments significantly reduced root rot incidence compared with fungicide and check control treatments. At all locations it was observed that Weed-Max (2 g/L) + Bacillus subtilis significantly reduced disease incidence of grown vegetables compared with Oligo-X (2 mL/L) + Trichoderma harzianum treatments. An obvious yield increase in all treatments was significantly higher than in the control. Also, the harvested yield in applied combined treatments at all locations was significantly higher than that in the fungicide and control treatments. Mokhtar M. Abdel-Kader and Nehal S. El-Mougy Copyright © 2013 Mokhtar M. Abdel-Kader and Nehal S. El-Mougy. All rights reserved. Erratum to “Incidence and Spatial Distribution of Caribbean Yellow Band Disease in La Parguera, Puerto Rico” Thu, 28 Nov 2013 18:31:14 +0000 Francisco J. Soto-Santiago and Ernesto Weil Copyright © 2013 Francisco J. Soto-Santiago and Ernesto Weil. All rights reserved. Role of the Digestive Gland in Ink Production in Four Species of Sea Hares: An Ultrastructural Comparison Thu, 21 Nov 2013 14:16:56 +0000 The ultrastructure of the digestive gland of several sea hare species that produce different colored ink (Aplysia californica produces purple ink, A. juliana white ink, A. parvula both white and purple ink, while Dolabrifera dolabrifera produces no ink at all) was compared to determine the digestive gland’s role in the diet-derived ink production process. Rhodoplast digestive cells and their digestive vacuoles, the site of digestion of red algal chloroplast (i.e., rhodoplast) in A. californica, were present and had a similar ultrastructure in all four species. Rhodoplast digestive cell vacuoles either contained a whole rhodoplast or fragments of one or were empty. These results suggest that the inability to produce colored ink in some sea hare species is not due to either an absence of appropriate digestive machinery, that is, rhodoplast digestive cells, or an apparent failure of rhodoplast digestive cells to function. These results also propose that the digestive gland structure described herein occurred early in sea hare evolution, at least in the common ancestor to the genera Aplysia and Dolabrifera. Our data, however, do not support the hypothesis that the loss of purple inking is a synapomorphy of the white-ink-producing subgenus Aplysia. Jeffrey S. Prince and Paul Micah Johnson Copyright © 2013 Jeffrey S. Prince and Paul Micah Johnson. All rights reserved. Collisions between Whales and Fast Ferries around Korean Waters Wed, 20 Nov 2013 18:40:53 +0000 Although there is heavy maritime traffic around Korean waters, collisions between whales and fast ferries around Korean waters are nearly unknown. A ship strike that was associated with a minke whale occurred near the southeastern part of Tsushima Island along the sailing route of the fast ferry between Korea and Japan on December 16, 2004. It was associated with a fast ferry that runs at a speed of approximately 46.1 kn (83 km/h) between Korea and Japan. This individual was certainly seriously injured or killed by this ship strike because large amounts of skin of this individual were attached to the surface of the fast ferry, and also large amounts of blood of this individual spread out in that area. However, fortunately, serious damage did not occur to the mariners and passengers of the ferry, although many passengers were knocked down to the floor of the fast ferry when the fast ferry collided with the minke whale. In addition, a total of 4 records of possible collisions between whales and fast ferries have occurred on the fast ferry route between Korea and Japan between 2004 and 2007. This study is the first formal report on collisions between whales and fast ferries around Korean waters. Although the effect of ship strikes on the survival of cetaceans distributed around Korean waters is not very high at present compared with that of other threats, such as entanglement in fishing gear, ship strikes can pose a significant potential threat to endangered cetaceans such as western gray whales. Therefore, it is necessary to prepare prevention measures for ship strikes for the conservation of cetaceans around Korean waters in the future. Kyung-Jun Song Copyright © 2013 Kyung-Jun Song. All rights reserved. Fluorometer Controlled Apparatus Designed for Long-Duration Algal-Feeding Experiments and Environmental Effect Studies with Mussels Wed, 06 Nov 2013 07:59:26 +0000 Experimental feeding and growth studies on filter-feeding organisms often rely on constant algal concentrations maintained over extended periods of time. Here we present a fluorometer controlled apparatus (FCA) designed for feeding experiments with suspension-feeding mussels at naturally low chlorophyll concentrations above 0.5 µg L−1. The principle used is feedback regulation of the algal concentration based on continuous monitoring of the fluorescence intensity of chlorophyll in water pumped through the apparatus from an aquarium with mussels. The filtration rate is monitored continuously as the rate of change of measured volume of an algal stock added to the aquarium for keeping a constant algal concentration. As an example, the FCA has been used to study the filtration rates of blue mussels (Mytilus edulis) at algal concentrations both near and above the incipient saturation level for reduced filtration activity. As another example to put the FCA into perspective as a reliable method for environmental effect studies, the apparatus has been used to demonstrate the acute effect of changing salinity on the filtration rate of M. edulis. Daniel Pleissner, Kim Lundgreen, Florian Lüskow, and Hans Ulrik Riisgård Copyright © 2013 Daniel Pleissner et al. All rights reserved. Tidal Influence on Nutrients Status and Phytoplankton Population of Okpoka Creek, Upper Bonny Estuary, Nigeria Thu, 31 Oct 2013 14:37:31 +0000 Okpoka Creek of the Upper Bonny Estuary in the Niger Delta is a tidal creek receiving organic anthropogenic effluents from its environs. The study investigated the influence of tides (low and high) on the species composition, diversity, abundance, and distribution of phytoplankton. The surface water and phytoplankton samples were collected monthly from May 2004 to April 2006 at both tides from ten stations according to standard methods. Phytoplankton was identified microscopically. Species diversity was calculated using standard indices. Data analyses were done using analysis of variance, Duncan multiple range, and descriptive statistics. Phosphate and ammonia exceeded international acceptable levels of 0.10 mg/L for natural water bodies indicating high nutrient status, organic matter, and potential pollutants. A total of 158 species of phytoplankton were identified. Diatoms dominated the phytoplankton (62.9%). Diversity indices of diatoms were (Margalef) and (Shannon). Pollution-indicator species such as Navicula microcephala, Nitzschia sigma, Synedra ulna (diatoms), Cladophora glomerata (green alga), Euglena acus (euglenoid), Anabeana spiroides (blue-green alga), and Ceratium furca (dinoflagellate) were recorded at either only low, high or both tides. Concerted environmental surveillance on Upper Bonny Estuary is advocated to reduce the inflow of pollutants from the Bonny Estuary into this Creek caused by tidal influence. O. A. Davies and O. A. Ugwumba Copyright © 2013 O. A. Davies and O. A. Ugwumba. All rights reserved. The Impacts of Ex Situ Transplantation on the Physiology of the Taiwanese Reef-Building Coral Seriatopora hystrix Sun, 20 Oct 2013 15:08:28 +0000 We sought to determine whether the Indo-Pacific reef-building coral Seriatopora hystrix performs in a similar manner in the laboratory as it does in situ by measuring Symbiodinium density, chlorophyll a (chl-a) concentration, and the maximum quantum yield of photosystem II () at the time of field sampling (in situ), as well as after three weeks of acclimation and one week of experimentation (ex situ). Symbiodinium density was similar between corals of the two study sites, Houbihu (an upwelling reef) and Houwan (a nonupwelling reef), and also remained at similar levels ex situ as in situ. On the other hand, both areal and cell-specific chl-a concentrations approximately doubled ex situ relative to in situ, an increase that may be due to having employed a light regime that differed from that experienced by these corals on the reefs of southern Taiwan from which they were collected. As this change in Symbiodinium chl-a content was documented in corals of both sites, the experiment itself was not biased by this difference. Furthermore, increased by only 1% ex situ relative to in situ, indicating that the corals maintained a similar level of photosynthetic performance as displayed in situ even after one month in captivity. Anderson B. Mayfield, Tung-Yung Fan, and Chii-Shiarng Chen Copyright © 2013 Anderson B. Mayfield et al. All rights reserved. Aerial Survey as a Tool to Estimate Abundance and Describe Distribution of a Carcharhinid Species, the Lemon Shark, Negaprion brevirostris Wed, 09 Oct 2013 15:23:51 +0000 Aerial survey provides an important tool to assess the abundance of both terrestrial and marine vertebrates. To date, limited work has tested the effectiveness of this technique to estimate the abundance of smaller shark species. In Bimini, Bahamas, the lemon shark (Negaprion brevirostris) shows high site fidelity to a shallow sandy lagoon, providing an ideal test species to determine the effectiveness of localised aerial survey techniques for a Carcharhinid species in shallow subtropical waters. Between September 2007 and September 2008, visual surveys were conducted from light aircraft following defined transects ranging in length between 8.8 and 4.4 km. Count results were corrected for “availability”, “perception”, and “survey intensity” to provide unbiased abundance estimates. The abundance of lemon sharks was greatest in the central area of the lagoon during high tide, with a change in abundance distribution to the east and western regions of the lagoon with low tide. Mean abundance of sharks was estimated at 49 (±8.6) individuals, and monthly abundance was significantly positively correlated with mean water temperature. The successful implementation of the aerial survey technique highlighted the potential of further employment for shark abundance assessments in shallow coastal marine environments. S. T. Kessel, S. H. Gruber, K. S. Gledhill, M. E. Bond, and R. G. Perkins Copyright © 2013 S. T. Kessel et al. All rights reserved.