Journal of Marine Biology

Proximate Composition and Its Seasonality of the Mediterranean Green Crab: Carcinus aestuarii Nardo, 1847 (Brachyura, Portunidae), in Southern Tunisian Waters (Central Mediterranean)

Mon, 10 Jun 2013 11:10:10 +0000

The Mediterranean green crab Carcinus aestuarii was recorded in Tunisian waters several years ago. However, since its record in the Gulf of Gabes, no studies have been carried out about the spread of this crab. Because there is a lack of nutritional information concerning this species, this study aimed to characterize the chemical composition of hepatopancreas and gonads of Carcinus aestuarii in view of potential health implication for consumers and to determine the seasonal nutritional quality of females and males taken separately for various size groups. In this study, a total of 1399 individuals were collected along the Sfax coast. The nutritional value of various edible parts of Carcinus aestuarii was evaluated, and gender differences in terms of edible yield and proximate composition, protein, mineral, lipid, and water content, were compared for season, age, and sex. The biochemical compositions were strongly influenced by sex, age, and seasons. The highest protein and lipid contents were detected in gonads and hepatopancreas of females. Autumn was the season with the highest protein content and lowest fat content. Therefore, people with particular diets constrains should consume the ovaries of females in autumn and it should moderate in winter. The hepatopancreas and gonads from Tunisian waters can be a good source of proteins and mineral.

Spirulina (Arthrospira): An Important Source of Nutritional and Medicinal Compounds

Abdulmumin A. Nuhu — Wed, 08 May 2013 13:59:03 +0000

Cyanobacteria are aquatic and photosynthetic organisms known for their rich pigments. They are extensively employed as food supplements due to their rich contents of proteins. While many species, such as Anabaena sp., produce hepatotoxins (e.g., microcystins and nodularins) and neurotoxins (such as anatoxin a), Spirulina (Arthrospira) displays anticancer and antimicrobial (antibacterial, antifungal, and antiviral) activities via the production of phycocyanin, phycocyanobilin, allophycocyanin, and other valuable products. This paper is an effort to collect these nutritional and medicinal applications of Arthrospira in an easily accessible essay from the vast literature on cyanobacteria.

Occurrence of White Sharks (Carcharodon carcharias) in Hawaiian Waters

Kevin Weng and Randy Honebrink — Thu, 11 Apr 2013 09:27:52 +0000

White sharks (Carcharodon carcharias) have been known in Hawaii (~158°W, 22°N) since the time of ancient Hawaiians. We compiled sightings and records from 1926 to the present (4 females, 2 males, and 8 unknown sex; 3.3–4.5 m total length) and compared them with satellite tracking records (7 females, 9 males, and 6 unknown; 3.7–5.3 m total length). White sharks have been sighted in Hawaii throughout the year, whereas satellite tracking studies show individuals near the North American coast during fall and offshore during spring for the eastern North Pacific population (northern fall/spring). The mismatch of these datasets could hypothetically be consistent with fall-sighted individuals being sourced from a different population or part of a resident population. However, recently documented multiyear movements of North American sharks revealed that the annual nearshore-offshore pattern does not hold for mature females, which ranged over larger areas and were offshore during the fall. We found that fall white shark sightings in Hawaii are predominantly of females, most likely visitors from the eastern North Pacific population. Misidentification of other species as white sharks frequently occurs by fishers and in the news media, and we suggest methods for discrimination of related species.

New Records of Atypical Coral Reef Habitat in the Kimberley, Australia

Z. T. Richards, M. Bryce, and C. Bryce — Thu, 04 Apr 2013 08:56:35 +0000

New surveys of the Kimberley Nearshore Bioregion are beginning to fill knowledge gaps about the region’s marine biodiversity and the national and international conservation significance of this little-known tropical reef system. Here we report the recent finding of two unique coral habitats documented at Adele Island and Long Reef during the Woodside 2009/2010 Collection Project surveys. Firstly, we report the finding of a subtidal zone of mixed corallith and rhodolith habitat which appears on current records, to be unprecedented in Australia. Secondly, we report the discovery of an atypical Organ Pipe Coral habitat zone and provide empirical evidence that this commercially valuable species reaches an unparalleled level of benthic cover. We provide additional details about the wider hard and soft coral assemblages associated with these unique habitats; discuss the potential biological causes and consequences of them, and make recommendations to benefit their conservation.

List of Zooplankton Taxa in the Caspian Sea Waters of Iran

Mon, 28 Jan 2013 08:59:34 +0000

A total of 61 zooplankton taxa were found in the southwestern Caspian Sea between 1996 and 2010. Thirteen of them were meroplankton taxa and forty-eight were holoplankton taxa. The occurrence of 14 freshwater taxa indicated the influence of the Anzali wetland and river inflows. The decrease in zooplankton taxa was detected since 1996-1997 and continued till 2010. Pleopis polyphemoides, the only one out of the nine recorded Cladocera species in 1996-1997, was found after 2001. Similarly, of the five Copepoda species recorded in 1996-1997, only one, Acartia tonsa, was found abundant during the 2001–2010 sampling period. It was striking that many species which were abundant in the Caspian Sea in 1996-1997 were not found after 2000. Many reasons could have contributed to the changes in the zooplankton composition of the southern Caspian Sea, notably the serious environmental degradation since the early 1990s. It is also possible that invasive species might play a role in wiping out some sensitive endemic species.

Water Flow Affects Zooplankton Feeding by the Scleractinian Coral Galaxea fascicularis on a Polyp and Colony Level

Tue, 04 Dec 2012 08:47:16 +0000

Several factors may affect heterotrophic feeding of benthic marine invertebrates, including water flow rate and polyp context (i.e., the presence of neighbouring polyps). We tested the interactive effects of water flow rate and polyp context on zooplankton feeding by the scleractinian coral Galaxea fascicularis. Single polyps and colonies were incubated in a flow cell for 30 minutes with an ambient Artemia nauplii concentration of 10,000 and water flow rates ranging from 1.25 to 40 cm . Water flow rate and polyp context showed significant main and interactive effects on feeding rates of G. fascicularis polyps. More specifically, feeding rates were optimal at flow rates of 1.25 cm for single polyps and 5 to 10 cm for polyps inhabiting colonies. The presence of epizoic acoelomorph flatworms may have negatively affected the observed feeding rates, especially at high flow. Our results demonstrate that water flow affects coral feeding and thus heterotrophic nutrient input at both a polyp and colony level. These findings are of relevance to our understanding of how biotic and abiotic factors interact on coral heterotrophy and may serve to optimise coral aquaculture.

Comparison of Inorganic and Organic Matter Sedimentation in a Natural Laboratory: A One-Year Study at Lough Hyne Marine Reserve, Ireland

Stefanie Broszeit, John Davenport, Mark Jessopp, Luke Harman, and Rob McAllen — Mon, 12 Nov 2012 16:12:42 +0000

Measuring sedimentation rates may provide useful information on the habitat preferences of marine organisms. To understand the effect of flow rates and meteorological conditions on sedimentation in the absence of other confounding factors, sedimentation of organic (OM) and inorganic (IOM) matters was measured at 6 sites in Lough Hyne Marine Reserve (a semienclosed marine lake) over the course of 13 months. During winter, both OM and IOM were imported to the Lough, peaking in December at Whirlpool, the site nearest to the Lough entrance, likely as a result of extreme weather conditions causing resuspension of matter outside the Lough. Highest inorganic matter (IOM) sedimentation occurred in December (47.36 gm−2d−1 at Whirlpool Cliff) and was related to November wind speeds (, ). Decreasing current speed also caused a decline in IOM sedimentation. Highest OM sedimentation occurred in December at Whirlpool (5.59 gm−2d−1), but was not related to meteorological conditions. No single environmental factor strongly influenced organic matter (OM) sedimentation. One-way ANOVAs on OM and log-transformed IOM data showed that sedimentation differed significantly amongst the six sites within the Lough. Increased plankton production in the Lough during summer led to increased OM sedimentation in areas of low current speed away from the entrance of the Lough.

High-Speed Vessel Noises in West Hong Kong Waters and Their Contributions Relative to Indo-Pacific Humpback Dolphins (Sousa chinensis)

Paul Q. Sims, Samuel K. Hung, and Bernd Würsig — Mon, 05 Nov 2012 17:14:04 +0000

The waters of West Hong Kong are home to a population of Indo-Pacific humpback dolphins (Sousa chinensis) that use a variety of sounds to communicate. This area is also dominated by intense vessel traffic that is believed to be behaviorally and acoustically disruptive to dolphins. While behavioral changes have been documented, acoustic disturbance has yet to be shown. We compared the relative sound contributions of various high-speed vessels to nearby ambient noise and dolphin social sounds. Ambient noise levels were also compared between areas of high and low traffic. We found large differences in sound pressure levels between high traffic and no traffic areas, suggesting that vessels are the main contributors to these discrepancies. Vessel sounds were well within the audible range of dolphins, with sounds from 315–45,000 Hz. Additionally, vessel sounds at distances ≥100 m exceeded those of dolphin sounds at closer distances. Our results reaffirm earlier studies that vessels have large sound contributions to dolphin habitats, and we suspect that they may be inducing masking effects of dolphin sounds at close distances. Further research on dolphin behavior and acoustics in relation to vessels is needed to clarify impacts.

Shell Shape Analysis and Spatial Allometry Patterns of Manila Clam (Ruditapes philippinarum) in a Mesotidal Coastal Lagoon

Wed, 03 Oct 2012 12:51:03 +0000

While gradual allometric changes of shells are intrinsically driven by genotype, morphometrical shifts can also be modulated by local environmental conditions. Consequently the common use of a unique dimension (usually length) to assess bivalves’ growth may mask phenotypic differences in valve shape among populations. A morphometric exhaustive study was conducted on Manila clam, Ruditapes philippinarum, by acquiring data in the French Arcachon Bay (intrasite phenotypic variability) and by comparing with other sites in the literature (intersite phenotypic variability). 2070 shells were subsampled, weighted, and automatically measured using TNPC software. Some ratios’ values indicate a relatively round and globular shape shell in comparison with other sites confirming poor conditions for some individuals. Among adult clams, three main morphological groups were identified and discussed according to spatial considerations. Allometric relations for pairs of shell descriptors were determined by testing classical linear and piecewise regression models on log-transformed relation of Huxley. A significant shape change correlated to size was observed; it corresponds to the second year of life of the clam. Relationships between density, disease, and shell shape are demonstrated and discussed related to other potential factors affecting shell shape. Finally, consequences on population regulation are addressed.

Histological Examination of Precious Corals from the Ryukyu Archipelago

Masanori Nonaka, Masaru Nakamura, Makoto Tsukahara, and James Davis Reimer — Thu, 13 Sep 2012 11:07:56 +0000

In this paper we examined the histology of three commercially valuable species of precious corals (Paracorallium japonicum, Corallium elatius, and C. konojoi) from the Ryukyu Archipelago. In order to observe their inner structure, samples were thin sectioned and examined with a digital light microscope. Colonies of C. konojoi had thicker coenenchyme and larger autozooids than those of C. elatius and P. japonicum. The sclerites of the three species tended to be concentrated in the outer layers of coenenchyme. The gastric cavities of autozooids of all three species were found to be relatively empty. Some symbiotic polychates were observed in the axis of P. japonicum. As well, a zoanthid (Corallizoanthus tsukaharai) was often observed living on the coenenchyme surface of P. japonicum. It is hoped our observations will provide a good foundation of future study of Japanese Coralliidae corals.

Larval Diel Vertical Migration of the Marine Gastropod Kelletia kelletii (Forbes, 1850)

Tue, 11 Sep 2012 11:10:07 +0000

Documenting larval behavior is critical for building an understanding of larval dispersal dynamics and resultant population connectivity. Nocturnal diel vertical migration (DVM), a daily migration towards the surface of the water column at night and downward during the day, can profoundly influence dispersal outcomes. Via laboratory experiments we investigated whether marine gastropod Kelletia kelletii larvae undergo nocturnal DVM and whether the behavior was influenced by the presence of light, ontogeny, and laboratory culturing column height. Larvae exhibited a daily migration pattern consistent with nocturnal diel vertical migration with lower average vertical positioning (ZCM) during day-time hours and higher vertical positioning at night-time hours. ZCM patterns varied throughout ontogeny; larvae became more demersal as they approached competency. There was no effect of column height on larval ZCM. DVM behavior persisted in the absence of light, indicating a possible endogenous rhythm. Findings from field plankton tows corroborated laboratory nocturnal DVM findings; significantly more K. kelletii were found in surface waters at midnight compared to at noon. Unraveling the timing of and the cues initiating DVM behavior in K. kelletii larvae can help build predictive models of dispersal outcomes for this emerging fishery species.

Protecting Wild Dolphins and Whales: Current Crises, Strategies, and Future Projections

Lori Marino, Frances Gulland, and E. C. M. Parsons — Thu, 06 Sep 2012 09:39:04 +0000

Species Diversity of Shallow Water Zoanthids (Cnidaria: Anthozoa: Hexacorallia) in Florida

James Davis Reimer, Colin Foord, and Yuka Irei — Mon, 03 Sep 2012 08:52:25 +0000

Shallow water zooxanthellate zoanthids are a common component of the coral reef ecosystems of the Caribbean. Despite this, their species diversity remains poorly understood. In this study, collected Palythoa, Zoanthus, Isaurus, and Terrazoanthus specimens from the waters of Florida were phylogenetically examined to obtain a better understanding of zoanthid species diversity in the Caribbean. Surprisingly, the results from analyses utilizing three DNA markers (mitochondrial 16S ribosomal DNA, cytochrome oxidase subunit I, and the internal transcribed spacer of ribosomal DNA) showed the presence of at least eleven species, of which up to four appear undescribed. Additionally, the presence of the genus Terrazoanthus in the Caribbean was confirmed for the first time. Attempts to match phylogenetic species or clades with original literature were hampered by vague and short original descriptions, and it is clear that for Atlantic Palythoa and Zoanthus species an in-depth and multidisciplinary investigation is needed to reconcile recent phylogenetic results such as in this study with traditional taxonomy. Furthermore, most shallow water zoanthid species from Florida were observed to have close, sister-species relationships with previously investigated species in the Pacific Ocean. These results indicate that many brachycnemic zoanthid species likely had a Caribbean-Pacific distribution until the formation of the Isthmus of Panama. However, due to inadvertent redescriptions, overall species diversity in these two common genera is likely much lower than literature indicates.

Gametogenesis and Spawning of Solenastrea bournoni and Stephanocoenia intersepta in Southeast Florida, USA

Jenna R. Lueg, Alison L. Moulding, Vladimir N. Kosmynin, and David S. Gilliam — Thu, 16 Aug 2012 10:11:04 +0000

This study constitutes the first report of the gametogenic cycle of the scleractinian corals Solenastrea bournoni and Stephanocoenia intersepta. Tissue samples were collected near Ft. Lauderdale, Florida, USA between July 2008 and November 2009 and processed for histological examination in an effort to determine reproductive mode and potential spawning times. Both S. bournoni and S. intersepta are gonochoric, broadcast spawning species. Gametogenesis of S. bournoni began in April or May while S. intersepta had a much longer oogenic cycle that began in December with spermatogenesis beginning in July. Though spawning was not observed in situ, spawning was inferred from the decrease of late stage gametes in histological samples. In addition, histological observations of oocyte resorption and released spermatozoa were used to corroborate spawning times. Data indicate that S. bournoni spawns in September while S. intersepta spawns after the full moon in late August or early September.

Vertical Patterns of Early Summer Chlorophyll a Concentration in the Indian Ocean with Special Reference to the Variation of Deep Chlorophyll Maximum

Wed, 15 Aug 2012 12:55:00 +0000

Vertical patterns of early summer chlorophyll a (Chl a) concentration from the Indian Ocean are presented, as well as the variations of depth and size-fractioned Chl a in the deep chlorophyll maximum (DCM). A total of 38 stations were investigated from 12 April to 5 May 2011, with 8 discrete-depth samples (7 fixed and 1 variable at real DCM) measured at each station. Depth-integrated Chl a concentration (∑Chl𝑎) varied from 11.5 to 26.8 mg m−2, whereas Chl a content at DCM ranged from 0.17 to 0.57 μg L−1 with picophytoplankton (<3 μm) accounting for 82% to 93%. The DCM depth varied from 55.6 to 91 m and shoaled latitudinally to northward. Moreover, our results indicated that the ∑Chl𝑎 could be underestimated by up to 9.3% with a routine sampling protocol of collecting samples only at 7 fixed depths as the real DCM was missed. The underestimation was negatively correlated to the DCM depth when it varied from 55.6 to 71.3 m (𝑟=−0.63, 𝑃<0.05) but positively correlated when it ranged from 75.8 to 91 m (𝑟=0.68, 𝑃<0.01). This indicates that in the Indian Ocean the greater the departure of the DCM from 75 m depth, the greater the underestimation of integrated Chl a concentration that could occur if the real DCM is missed.

The Negative Impacts of Whale-Watching

E. C. M. Parsons — Wed, 15 Aug 2012 07:14:49 +0000

Whale watching is an international industry worth more than US$2 billion globally and is currently the greatest economic activity reliant upon cetaceans. However, there is concern that whale watching is detrimental to the target species. Numerous studies have shown that cetaceans exhibit behavioral changes in response to whale-watching boat traffic. Some of these behavioral changes involve inhibiting biologically important behaviors such as feeding and resting. There is convincing evidence for some species that these can translate into population-level effects such as reduced reproductive rates. Whale watching can also cause direct mortality through collisions between vessels and animals. The introduction of guidelines or regulations for whale watching has been the most common method of trying to mitigate the impacts of boat-based whale watching. However, there is great variety in the comprehensiveness of guidelines, and even if operators have guidelines, compliance with them can be poor. Compliance might be improved if guidelines have legal under-pinnings, with monitoring and enforcement or via pressure to comply by other operators and whale-watching tourists. Simple guidelines may be more easily complied with that ones requiring specialist knowledge. Likewise undertaking simple measures, such as establishing temporal or spatial “refuges” protecting biologically important areas (e.g., feeding grounds) where whale-watching activity is prohibited, could be an appropriate mitigation strategy.

Sponge Farming Trials: Survival, Attachment, and Growth of Two Indo-Pacific Sponges, Neopetrosia sp. and Stylissa massa

Karin Schiefenhövel and Andreas Kunzmann — Mon, 13 Aug 2012 13:32:04 +0000

Sponges, an important part of the reef ecosystem, are of commercial value for public aquaria, pharmacology and chemistry. With the growing demand for sponges, natural resources are at risk of being overexploited. Growing of sponges in artificial or semi natural farms is an alternative. In this study different farming methods were tested on two Indo-Pacific sponge species, Neopetrosia sp. and Stylissa massa. Survival, growth and attachment ability were observed with different substrates (suspended ropes, coral boulders and artificial substrate), two types of aquaria with different water volume and two different field sites in Indonesia. The two species responded differently to their individual locations and environmental stresses. Survival, growth and attachment rates of Neopetrosia sp. at the field site are depending on the cultivation method, we found highest volume increment (27–35%) for a horizontal line in the field. Whereas the volume increase for S. massa did not show any differences for the different transplantation methods, Neopetrosia sp. generally showed higher rates than S. massa. Further aquaria experiments, for example, on nutrient supply, should be tested to receive more detailed data about sponges, particularly because almost all fragments of both species showed a decline or steady state in mean length.

On the Occurrence of the Blunthead Puffer, Sphoeroides pachygaster (Osteichthyes: Tetraodontidae), in the Strait of Messina (Central Mediterranean)

Thu, 09 Aug 2012 14:13:11 +0000

The record of Sphoeroides pachygaster reveals the presence of the species in the Strait of Messina (Central Mediterranean Sea). The adult species was captured on 15 march 2012. It measured 280 mm of total length and weighed 461.5 g. Morphometric measurements (mm) and meristic counts were reported in this paper.

Reef Flat Community Structure of Atol das Rocas, Northeast Brazil and Southwest Atlantic

Adriana C. Fonseca, Roberto Villaça, and Bastiaan Knoppers — Sun, 05 Aug 2012 09:14:14 +0000

This study was conducted during 1999 to 2002 and addresses the community structure and some ecological aspects of the benthic reef flat assemblages of Atol das Rocas, located offshore the NE brazilian coast. It corresponds to the sole atoll of the SW Atlantic, which characterized by a shallow topography and is almost completely built by coralline algae. The turf forming red macroalgae Digenea simplex and the crustose coralline Hydrolithon pachydermum were the dominant species of the reef flat. The crustose green macroalgae Dictyosphaeria ocellata and the turf forming red macroalgae Gelidiella acerosa were the subdominant species. Biomass values of D. simplex were about twice higher than the other species, pointing out to its relevance in the community structure of this reef zone. Biodiversity indices indicated a high equitability within the few species observed and a relative temporal stability of the community structure. Some local spatial variations were found in the community structure of the reef flat zone, enabling the definition of three subhabitats. The patterns of distribution and abundance of the benthic organisms seem to be related to the environmental conditions of the reef flat, such as low water turbulence, lengthy periods of aerial exposure, and low herbivore pressure.

Incidence and Spatial Distribution of Caribbean Yellow Band Disease in La Parguera, Puerto Rico

Francisco J. Soto-Santiago and Ernesto Weil — Mon, 30 Jul 2012 14:13:45 +0000

The incidence and spatial distribution patterns of Caribbean Yellow Band Disease (CYBD) on the important frame-builder coral Montastraea faveolata were assessed by counting, tagging, and mapping all diseased and healthy colonies for one year in each of three 100 m2 quadrats on two inner, mid-shelf, and shelf-edge reefs off La Parguera, Puerto Rico. Healthy colonies were checked every month from January to December of 2009 to monitor disease spread within each quadrant. Incidence increased significantly from winter (0.7±0.8% SE) to summer (1.5±1.1% SE, 𝑛=23, Sign Test; 𝑍=2.40; 𝑃=0.01). Mid-shelf reefs had the highest host abundance and showed significantly higher CYBD incidence (2.1±1.4% SE, 𝑛=14) compared to the other zones (𝐻=9.74;𝑑𝑓=2; 𝑃=0.04). The increased incidence in the summer suggests that warmer months favor development of CYBD on M. faveolata. Results showed aggregated patterns of CYBD when all colonies (i.e., healthy + diseased) at the spatial scales sampled were analyzed on each reef. This suggests facilitation of disease spread between aggregated colonies within populations. Similar stressful conditions then might trigger the disease in susceptible, aggregated colonies harboring the potential pathogens.

Social and Behavioural Factors in Cetacean Responses to Overexploitation: Are Odontocetes Less “Resilient” Than Mysticetes?

Paul R. Wade, Randall R. Reeves, and Sarah L. Mesnick — Sun, 29 Jul 2012 14:13:05 +0000

Many severely depleted populations of baleen whales (Mysticeti) have exhibited clear signs of recovery whereas there are few examples in toothed whales (Odontoceti). We hypothesize that this difference is due, at least in part, to social and behavioural factors. Clearly, a part of the lack of resilience to exploitation is explained by odontocete life history. However, an additional factor may be the highly social nature of many odontocetes in which survival and reproductive success may depend on: (a) social cohesion and organization, (b) mutual defence against predators and possible alloparental care, (c) inter-generational transfer of “knowledge”, and (d) leadership by older individuals. We found little evidence of strong recovery in any of the depleted populations examined. Their relatively low potential rates of increase mean that odontocete populations can be over-exploited with take rates of only a few percent per year. Exploitation can have effects beyond the dynamics of individual removals. Four species showed evidence of a decrease in birth rates following exploitation; potential mechanisms include a deficit of adult females, a deficit of adult males, and disruption of mating systems. The evidence for a lack of strong recovery in heavily exploited odontocete populations indicates that management should be more precautionary.

Summary of Reported Whale-Vessel Collisions in Alaskan Waters

Tue, 17 Jul 2012 09:13:51 +0000

Here we summarize 108 reported whale-vessel collisions in Alaska from 1978–2011, of which 25 are known to have resulted in the whale's death. We found 89 definite and 19 possible/probable strikes based on standard criteria we created for this study. Most strikes involved humpback whales (86%) with six other species documented. Small vessel strikes were most common (<15 m, 60%), but medium (15–79 m, 27%) and large (≥80 m, 13%) vessels also struck whales. Among the 25 mortalities, vessel length was known in seven cases (190–294 m) and vessel speed was known in three cases (12–19 kn). In 36 cases, human injury or property damage resulted from the collision, and at least 15 people were thrown into the water. In 15 cases humpback whales struck anchored or drifting vessels, suggesting the whales did not detect the vessels. Documenting collisions in Alaska will remain challenging due to remoteness and resource limitations. For a better understanding of the factors contributing to lethal collisions, we recommend (1) systematic documentation of collisions, including vessel size and speed; (2) greater efforts to necropsy stranded whales; (3) using experienced teams focused on determining cause of death; (4) using standard criteria for validating collision reports, such as those presented in this paper.

Cetaceans and Marine Debris: The Great Unknown

Mark Peter Simmonds — Thu, 28 Jun 2012 19:15:38 +0000

Plastics and other marine debris have been found in the gastrointestinal tracts of cetaceans, including instances where large quantities of material have been found that are likely to cause impairment to digestive processes and other examples, where other morbidity and even death have resulted. In some instances, debris may have been ingested as a result of the stranding process and, in others, it may have been ingested when feeding. Those species that are suction or “ram” feeders may be most at risk. There is also evidence of entanglement of cetaceans in marine debris. However, it is usually difficult to distinguish entanglement in active fishing gear from that in lost or discarded gear. The overall significance of the threat from ingested plastics and other debris remains unclear for any population or species of cetaceans, although there are concerns for some taxa, including at the population level, and marine debris in the oceans continues to grow. Further research including the compilation of unpublished material and the investigation of important habitat areas is strongly recommended.

Raphides in the Uncalcified Siphonous Green Seaweed, Codium minus (Schmidt) P. C. Silva

Jeffrey S. Prince — Thu, 28 Jun 2012 14:18:10 +0000

The vacuole of utricles, the outermost cell layer of the siphonous green seaweed, Codium minus, had numerous single needles and needle bundles. The crystals composing each needle appeared arranged in a twisted configuration, both ends were pointed, and each needle was contained in a matrix or membrane; bundles of needles appeared enclosed by a matrix. Chemical and electron diffraction analysis indicated that the needles consisted of calcium oxalate. This is the first paper on terrestrial plant-like raphides in an alga.

The Reproductive Biology of the Softshell Clam, Mya arenaria, in Ireland, and the Possible Impacts of Climate Variability

M. E. Cross, S. Lynch, A. Whitaker, R. M. O'Riordan, and S. C. Culloty — Thu, 21 Jun 2012 08:09:07 +0000

Little is known about the biology of the softshell clam in Europe, despite it being identified as a potential species to culture for food in the future. Monthly samples of the softshell clam, Mya arenaria, were collected intertidally from Co. Wexford, Ireland, over a period of sixteen months. The mean weight of sampled individuals was 74±4.9 g and mean length was 8.2±0.2 cm. Histological examination revealed a female-to-male ratio of 1 : 1.15. In 2010, M. arenaria at this site matured over the summer months, with both sexes either ripe or spawning by August. A single spawning event was recorded in 2010, completed by November. Two unusually cold winters, followed by a warmer-than-average spring, appear to have affected M. arenaria gametogenesis in this area, potentially affecting the time of spawning, fertilisation success, and recruitment of this species. No hermaphrodites were observed in the samples collected, nor were any pathogens observed. Timing of development and spawning is compared with the coasts of eastern North America and with other European coasts.

The Painful Side of Trap and Fixed Net Fisheries: Chronic Entanglement of Large Whales

Michael J. Moore and Julie M. van der Hoop — Thu, 07 Jun 2012 09:47:49 +0000

Concern over the well-being of marine mammals at sea has focused on intentional harvests, both in terms of individual welfare and population sustainability. Unintentional mortalities from fishing gear entanglement are primarily seen as a risk to population viability. Additionally, larger whales breaking free of, and subsequently carrying, fixed trap and net gear are subject to a very slow demise, averaging 6 months in the case of the North Atlantic right whale (Eubalaena glacialis). Chronic cases can involve impaired foraging, increased drag, infection, hemorrhage, and severe tissue damage. The individual suffering of these cases appears to be extreme. Thus management measures should go beyond legally mandated conservation measures to include avoidance of such scenarios. Seafood consumers could succeed, where laws have failed, to demand fishing practices that do not kill whales in this manner. The effective absence of such demands would seem to reflect the cryptic nature of these cases to most consumers.

River Cetaceans and Habitat Change: Generalist Resilience or Specialist Vulnerability?

Brian D. Smith and Randall R. Reeves — Mon, 21 May 2012 13:41:25 +0000

River dolphins are among the world’s most threatened mammals, and indeed the baiji (Lipotes vexillifer), a species endemic to China's Yangtze River, is likely extinct. Exploitation for products such as meat, oil, and skins has been a lesser feature in the population histories of river dolphins compared to most large mammals. Habitat factors are therefore of particular interest and concern. In this paper we attempt to describe the population-level responses of river dolphins to habitat transformation. We find circumstantial but compelling evidence supporting the view that, at a local scale, river dolphins are opportunists (generalists) capable of adapting to a wide range of habitat conditions while, at a river basin scale, they are more appropriately viewed as vulnerable specialists. The same evidence implies that the distributional responses of river dolphins to basinwide ecological change can be informative about their extinction risk, while their local behaviour patterns may provide important insights about critical ecological attributes. Empirical studies are needed on the ecology of river cetaceans, both to inform conservation efforts on behalf of these threatened animals and to help address broader concerns related to biodiversity conservation and the sustainability of human use in several of the world's largest river systems.

Exploring Relationships between Demersal Resources and Environmental Factors in the Ionian Sea (Central Mediterranean)

Tue, 08 May 2012 13:50:44 +0000

The relationships between the abundance of demersal resources, environmental variables, and fishing pressure in the north-western Ionian Sea in the last two decades were evaluated. Data on the density collected during seventeen trawl surveys carried out from 1985 to 2005 were used. The following species were considered: Aristaeomorpha foliacea, Nephrops norvegicus, and Parapenaeus longirostris for crustaceans; Merluccius merluccius, Phycis blennoides, and Mullus barbatus for teleost fish. The recruitment index was also considered for N. norvegicus, P. longirostris, M. merluccius and Mullus barbatus. Six candidate models were evaluated for each density and recruitment data set either combining fishing effort with global (NAO) and regional (SST and precipitation) climatic indices, or models separately involving fishing effort, NAO, or regional climatic indices as the only predictive variable. Model selection was carried out using an information-theoretical approach that applies Akaike’s Information Criterion (AIC). High changes over time were observed for the density data and recruitment indices in each species. Apart from hake abundance and recruitment data, for which a clear positive relationship with the NAO index alone was detected, the changes observed in the other species seem to be the consequence of the interaction between bottom-up effects linked to changes in physical environment and top-down ones due to the fishing pressure.

Modelling Reef Fish Population Responses to Fisheries Restrictions in Marine Protected Areas in the Coral Triangle

Divya Varkey, Cameron H. Ainsworth, and Tony J. Pitcher — Wed, 28 Mar 2012 13:27:14 +0000

Marine ecosystem models are used to investigate marine protected area (MPA) benefits for coral reef ecosystems located in Raja Ampat, in the heart of the Coral Triangle. Field data from an integrated and diverse research project is used to develop a spatial ecosystem model using Ecopath, Ecosim, and Ecospace modelling software. The ecological and fisheries responses of a reef ecosystem to different levels of fishing effort restrictions inside MPAs are explored. The trade-offs of allowing some fisheries to operate inside the MPAs versus designating the MPAs as no-take zones are highlighted. The results show that rapid rebuilding of reef fish populations, especially the large charismatic species, requires no-take areas. Distinct trade-offs in spillover benefits are observed between partially fished and no-take MPAs.

Histology and Mucous Histochemistry of the Integument and Body Wall of a Marine Polychaete Worm, Ophryotrocha n. sp. (Annelida: Dorvilleidae) Associated with Steelhead Trout Cage Sites on the South Coast of Newfoundland

H. M. Murray, D. Gallardi, Y. S. Gidge, and G. L. Sheppard — Mon, 26 Mar 2012 13:17:42 +0000

Histology and mucous histochemistry of the integument and body wall of a marine polychaete worm, Ophryotrocha n. sp. (Annelida: Dorvilleidae) associated with Steelhead trout cage sites on the south coast of Newfoundland. A new species of polychaete (Ophryotrocha n. sp. (Annelida: Dorvilleidae)) was identified from sediment below Steelhead trout cages on the south coast of Newfoundland, Canada. The organisms were observed to produce a network of mucus in which groups of individuals would reside. Questions regarding the nature and cellular source of the mucus were addressed in this study. Samples of worms were taken from below cages and transported to the laboratory where individuals were fixed for histological study of the cuticle and associated mucus histochemistry. The body wall was organized into segments with an outer cuticle that stained strongly for acid mucopolysaccharides. The epidermis was thin and supported by loose fibrous connective tissue layers. Channels separating individual segments were lined with cells staining positive for Alcian blue. Mucoid cellular secretions appeared thick and viscous, strongly staining with Alcian blue and Periodic Acid Schiff Reagent. It was noted that lateral channels were connected via a second channel running through the anterior/posterior axis. The role of mucus secretion is discussed.