Journal of Marine Biology http://www.hindawi.com The latest articles from Hindawi Publishing Corporation © 2015 , Hindawi Publishing Corporation . All rights reserved. On the Interplay between Cannibalism and Harvest in Stage-Structured Population Models Wed, 17 Jun 2015 07:32:58 +0000 http://www.hindawi.com/journals/jmb/2015/580520/ By use of a nonlinear stage-structured population model the role of cannibalism and the combined role of cannibalism and harvest have been explored. Regarding the model, we prove that in most parts of parameter space it is permanent. We also show that the transfer from stability to nonstationary dynamics always occurs when the unique stable equilibrium undergoes a supercritical Neimark-Sacker (Hopf) bifurcation. Moreover, the dynamic consequences of catch depend not only on which part of the population (immature or mature) is exposed to increased harvest pressure but also on which part of the immature population (newborns, older immature individuals) suffers from cannibalism. Indeed, if only newborns are exposed to cannibalism an enlargement of harvest pressure on the mature part of the population may act in a stabilizing fashion. On the other hand, whenever the whole immature population is exposed to cannibalism there are parts in parameter space where increased harvest on the mature population acts in a destabilizing fashion. Arild Wikan Copyright © 2015 Arild Wikan. All rights reserved. Viability of Sea Fan Populations Impacted by Disease: Recruitment versus Incidence Tue, 26 May 2015 11:14:54 +0000 http://www.hindawi.com/journals/jmb/2015/987060/ Diseases are a threat to the viability of an increasing number of coral populations. In this study we analyze the effect of infection and recruitment rate on the viability and structure of sea fan (Gorgonia ventalina) populations using a size-based matrix model parameterized with data from field studies. The model predicts that the viability of sea fan populations is strongly influenced by disease incidence and recruitment. Under high recruitment rate, the disease incidence threshold for population viability is 0.12/yr. However, populations with no or low incidence may also go locally extinct given persistent low recruitment. The model also predicts an effect of recruitment on disease prevalence. Everything else being equal, sites with low recruitment will exhibit higher disease prevalence than ones with high recruitment, particularly in medium and large colonies. Elasticity analysis reveals that changes in colony survivorship are likely to have the strongest effect on population growth rate, particularly given low recruitment. We conclude that under current levels of incidence sea fan populations in the Caribbean are not at risk. However, future epizootics are likely to produce local extinctions particularly if coinciding spatially or temporally with low recruitment. Alberto M. Sabat and Carlos Toledo-Hernández Copyright © 2015 Alberto M. Sabat and Carlos Toledo-Hernández. All rights reserved. Ultrastructural Comparison of Processing of Protein and Pigment in the Ink Gland of Four Species of Sea Hares Sun, 24 May 2015 11:25:04 +0000 http://www.hindawi.com/journals/jmb/2015/847961/ The ink glands of four sea hare species (Aplysia californica, A. parvula, A. juliana, and Dolabrifera dolabrifera) were compared to determine where ink protein is synthesized, how it is incorporated into protein storage vesicles, and the degree of variation in the structure of the ink gland. Ink protein was synthesized in RER cells and stored in amber and white vesicles. Lack of competent RER cells in the ink gland of D. dolabrifera was correlated with the absence of ink protein. Ink protein had similar characteristics in all three Aplysia species but, again, it was absent in D. dolabrifera. Its uptake involved pinocytosis by protein vesicle cell membranes. Granulate cells showed little variation in structure among the four species, the opposite was the case for RER cells. The conversion of the red algal pigment, phycoerythrin, to phycoerythrobilin (PEB) occurs in the digestive gland but the change of PEB to aplysioviolin (APV), the form of pigment released by the ink gland, occurs in the ink gland itself by both granulate cells and pigment vesicles. The literature describes five types of vesicles based upon color and contents in the ink gland of these four species. We report only three types of vesicle: colored (purple), protein (white and amber), and transparent (includes clear vesicles). Jeffrey S. Prince and Paul Micah Johnson Copyright © 2015 Jeffrey S. Prince and Paul Micah Johnson. All rights reserved. Comparison of Three Methods for Determining the Prey Preference of the Muricid Snail Reishia clavigera Sun, 10 May 2015 11:59:28 +0000 http://www.hindawi.com/journals/jmb/2015/484392/ We propose an appropriate method for investigating the prey preferences of the muricid snail Reishia clavigera (Küster, 1860) with limited collection of live prey. We compared 3 methods for examining the prey preference. The first was a predation experiment, conducted with dead prey instead of live prey. The second was a prey choice test using a few preys. In this experiment, both live and dead prey were used. The last method was a stable isotope analysis of R. clavigera and its putative prey items. Using live prey, bivalves were the most preferred prey, but goose barnacle was the most preferred prey species in experiments using dead prey. The carbon and nitrogen stable isotope analysis supported the live prey experiment. Since R. clavigera prefer preying on live prey but will scavenge or cannibalize when no other food is available in natural habitats, experimental methods using dead prey are not suitable for investigating its prey preferences. Considering the damage to natural habitats, the prey choice test is ecologically benign. Taken together, our findings suggested the prey choice test is the most appropriate method of identifying the prey preferences of muricid snails when large numbers of live preys are difficult to collect. Morihiko Tomatsuri and Koetsu Kon Copyright © 2015 Morihiko Tomatsuri and Koetsu Kon. All rights reserved. Origins and Implications of a Primary Crown-of-Thorns Starfish Outbreak in the Southern Great Barrier Reef Thu, 26 Mar 2015 12:04:15 +0000 http://www.hindawi.com/journals/jmb/2015/809624/ The crown-of-thorns starfish (COTS) is a major predator of hard corals. Repeated COTS outbreaks in the Cairns and Central sections of the Great Barrier Reef (GBR) have been responsible for greater declines in coral cover than any other type of disturbance, including cyclones, disease, and coral bleaching. Knowledge of the precise timing and location of primary outbreaks could reveal the initial drivers of outbreaks and so could indicate possible management measures. In the central GBR, COTS outbreaks appear to follow major flooding events, but despite many years of observations, no primary outbreak has ever been unequivocally identified in the central and northern GBR. Here we locate a primary outbreak of COTS on the southern GBR which is not correlated with flooding. Instead it appears to have been the result of a combination of life history traits of COTS and prevailing oceanographic conditions. The hydrodynamic setting implies that the outbreak could disperse larvae to other reefs in the region. Ian Miller, Hugh Sweatman, Alistair Cheal, Mike Emslie, Kerryn Johns, Michelle Jonker, and Kate Osborne Copyright © 2015 Ian Miller et al. All rights reserved. Seasonal Changes in Glycogen Contents in Various Tissues of the Edible Bivalves, Pen Shell Atrina lischkeana, Ark Shell Scapharca kagoshimensis, and Manila Clam Ruditapes philippinarum in West Japan Tue, 24 Feb 2015 06:38:07 +0000 http://www.hindawi.com/journals/jmb/2015/593032/ The types of tissues accumulating glycogen and seasonal changes in glycogen content were investigated in the following shell species: pen shell Atrina lischkeana, ark shell Scapharca kagoshimensis, and Manila clam Ruditapes philippinarum. Comparison of the results showed that the adductor muscle or foot was the main glycogen reservoir and the levels varied seasonally. The adductor muscle in the pen shell showed higher glycogen content during spring and lower content during autumn. The ark shell, on the other hand, showed higher content during winter and spring and lower content during summer and autumn, while the Manila clam showed higher glycogen content during spring and summer and lower content during autumn and winter. These results revealed that the adductor muscle in pen shells and the foot in ark shells and Manila clams act as the main storage tissues for glycogen in the three species studied and that these tissues are suitable to analyze glycogen prevalence to estimate individual physiological condition. Tatsuya Yurimoto Copyright © 2015 Tatsuya Yurimoto. All rights reserved. Estimating the Potential Production of the Brown Mussel Perna perna (Linnaeus, 1758) Reared in Three Tropical Bays by Different Methods of Condition Indices Thu, 22 Jan 2015 09:31:09 +0000 http://www.hindawi.com/journals/jmb/2015/948053/ Perna perna (Linnaeus, 1758) is the main marine bivalve mussel yielded commercially in Brazil. In spite of this, scientific data is very scarce regarding its productivity in tropical shallow waters. The Condition Index (CI) is used worldwide in mariculture to assess animal health, harvest time, and yield. In this study, the authors used CI results from nine different methods to assess the season effect on the mussel CI and also to evaluate the potential yield of three southern Brazilian bays. The results from nine CI methods were used for the comparison of the seasonality and yield of mussels reared in three marine bays. Sampling was carried out monthly within two 4-month periods, from December 2008 to August 2009. The results show a trend for seasonal effects on the CI results. The winter months showed the highest and the lowest values. Between bays, higher CI values were detected in animals reared at Sepetiba Bay, followed by Guanabara Bay and Ilha Grande Bay. We suggest that the CI (that considers the ratio between bivalve soft tissue wet weight and total length) should be used by fishermen, since this formula was able to detect differences between sites and is more easily applied. Petrus Galvao, Renan Longo, João Paulo Machado Torres, and Olaf Malm Copyright © 2015 Petrus Galvao et al. All rights reserved. Composition of Periphyton Community on Water Hyacinth (Eichhornia crassipes): In Analysis of Environmental Characteristics at Ejirin Part of Epe Lagoon in Southwestern Nigeria Thu, 08 Jan 2015 08:34:57 +0000 http://www.hindawi.com/journals/jmb/2015/376986/ The composition of periphyton community on water hyacinth was investigated at Ejirin, part of Epe Lagoon, in relation to environmental characteristics from December 2012 to May 2013. A total of 14,536 individuals of 104 species belonging to five divisions were identified, with Bacillariophyta (82.69%), Cyanobacteria (10.43%), Chlorophyta (5.63%), and Euglenophyta (1.15%). The total species abundance observed showed a strong correlation with rainfall () and strongly significant correlation with TDS (; ). Biochemical oxygen demand value remained (BOD) 4.8 mg/L while Shannon-Wiener index value remained (. The presence of the following organisms could be used as an indicator of environmentally stressed aquatic ecosystem: euglenoids, blue green algae, Nitzschia palea, Surirella sp., Pinnularia sp., Gomphonema parvulum, Mougeotia sp., Spirogyra sp., Trachelomonas affinis (Lemm.), and T. ensifera Daday; T. gibberosa Playf. and Phormidium articulatum; Lyngbya intermedia; Cymbella ventricosa; Eunotia arcus; Surirella linearis and Closterium parvulum Nag. A. I. Inyang, K. E. Sunday, and D. I. Nwankwo Copyright © 2015 A. I. Inyang et al. All rights reserved. Catalase Activity in Brown Mussels (Perna perna) under Acute Cadmium, Lead, and Copper Exposure and Depuration Tests Thu, 25 Dec 2014 09:32:31 +0000 http://www.hindawi.com/journals/jmb/2014/830657/ Brown mussels (Perna perna) were exposed to cadmium (Cd), lead (Pb), and copper (Cu) concentrations under acute exposure and exposure-depuration tests for the estimation of biochemical biomarker catalase (CAT). The acute tests showed accumulated Cd, Pb, and Cu in Perna perna correlated linearly with the exposure concentrations (, , and for Cd, Pb, and Cu, resp.). The results of CAT increased significantly in tissues of treatment mussels after 72 h exposure when compared to control. The values of total protein were disturbed in exposed groups when compared with control. These results suggest that metabolites and catalase activity were affected by heavy metal exposures. Analysis using the Spearman rank correlation coefficient showed that the CAT activity appeared to have a significant positive correlativity (, , and for Cd, Pb, and Cu, resp.) with the accumulated Cd, Pb, and Cu concentrations, respectively. The result of exposure-depuration tests showed that there is a general tendency for CAT to decrease in depuration phase, suggesting that the induction of catalase is metal and/or mixture of metals dependent. Kamel Boudjema, Sidali Kourdali, Nabila Bounakous, Abdellah Meknachi, and Abdelmalek Badis Copyright © 2014 Kamel Boudjema et al. All rights reserved. Olive Ridley Sea Turtle Hatching Success as a Function of Microbial Abundance and the Microenvironment of In Situ Nest Sand at Ostional, Costa Rica Mon, 22 Dec 2014 00:10:05 +0000 http://www.hindawi.com/journals/jmb/2014/351921/ Sea turtle hatching success at mass nesting beaches is typically lower than at solitary nesting beaches, presumably due in part to high rates of microbial metabolism resulting from the large input of organic matter from turtle eggs. Therefore, we tested the hypothesis that hatching success varies across areas of the beach in conjunction with differences in the physical nest environment and microbial abundance of in situ olive ridley sea turtle nests at Ostional, Costa Rica. We marked natural nests in high-density, low-density, and tidal-wash nesting areas of the beach and monitored clutch pO2 and temperature throughout the incubation period. We quantified hatching success and collected samples of nest sand during nest excavations. We quantified microbial abundance (bacteria and fungi) with a quantitative polymerase chain reaction (qPCR) analysis. Hatching success was lower in nests with lower pO2, higher temperatures, higher organic matter content, and higher microbial abundance. Our results suggest that the lower oxygen within the nest environment is likely a result of the high microbial abundance and rates of decomposition in the nest sand and that these factors, along with increased temperature of clutches in the high-density nesting area, are collectively responsible for the low hatching success at Ostional. Vanessa S. Bézy, Roldán A. Valverde, and Craig J. Plante Copyright © 2014 Vanessa S. Bézy et al. All rights reserved. The First Molecular Characterization of Picocyanobacteria from the Argentine Sea Thu, 20 Nov 2014 00:00:00 +0000 http://www.hindawi.com/journals/jmb/2014/237628/ 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 http://www.hindawi.com/journals/jmb/2014/631309/ 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 http://www.hindawi.com/journals/jmb/2014/819263/ 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 http://www.hindawi.com/journals/jmb/2014/436789/ 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 http://www.hindawi.com/journals/jmb/2014/218451/ 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 http://www.hindawi.com/journals/jmb/2014/297631/ 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 http://www.hindawi.com/journals/jmb/2014/918614/ 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 http://www.hindawi.com/journals/jmb/2014/953587/ 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 http://www.hindawi.com/journals/jmb/2014/640785/ 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 http://www.hindawi.com/journals/jmb/2014/241410/ 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 http://www.hindawi.com/journals/jmb/2014/275305/ 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 http://www.hindawi.com/journals/jmb/2014/519510/ 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 http://www.hindawi.com/journals/jmb/2014/913932/ 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 http://www.hindawi.com/journals/jmb/2014/769356/ 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 http://www.hindawi.com/journals/jmb/2014/621238/ 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 http://www.hindawi.com/journals/jmb/2014/748267/ 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 http://www.hindawi.com/journals/jmb/2014/470715/ 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 http://www.hindawi.com/journals/jmb/2014/842381/ 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 http://www.hindawi.com/journals/jmb/2014/462529/ 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 http://www.hindawi.com/journals/jmb/2014/267917/ 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.