Rapana Venosa Research Articles

Effects of temperature, salinity, diet and stocking density on development of the veined Rapa whelk, Rapana venosa (Valenciennes, 1846) larvae

The veined rapa whelk Rapana venosa (Valenciennes, 1846) is an important and valuable fishery resource but has not been cultured on a large scale. We studied the effects of environmental factors, temperature, salinity, diet, and stocking density, on growth and survival of larvae to determine optimal artificial culture conditions. The optimal temperature was 25–31 °C at 30 ppt at densities of about 200 veligers per liter, under which the mean shell length (737–1006 μm) and survival rate (36–45%) were higher than those held at other temperatures. When cultured under a salinity of 25 ppt at 25 °C with densities of about 200 veligers per liter, larvae had the highest mean shell length (878.45–917.88 μm) and survival rate (29.75%). Larvae were fed a mixed diet, Pseudoisochrysis paradoxa + Tetraselmis chui + Chlorella vulgaris. Optimal stocking density was 300 veligers per liter for the first 5 days and was 100 veligers per liter afterward at 25 °C and 30 ppt.

Консорты брюхоногого моллюска Rapana venosa (Valenciennes, 1846) в северной части Чёрного моря. Часть II: Mollusca (Polyplacophora, Bivalvia)

Исследование моллюсков-симбионтов хищной гастроподы Rapana venosa (Valenciennes, 1846) является продолжением работы по описанию таксономического состава комплекса эпибионтов, формирующегося на раковине рапаны. Современные исследования инвазивной гастроподы R. venosa показывают, что экологическая роль этого вида не сводится только к хищничеству. На довольно крупной раковине рапаны может формироваться специфический комплекс организмов-эпибионтов, рассматриваемый как консорция, ядром которой является R. venosa. Консорция брюхоногого моллюска-вселенца R. venosa является малоизученным и неучтённым звеном бентосных сообществ и экосистемы шельфа Чёрного моря. Для изучения консортного сообщества рапаны были осуществлены сборы в 7 районах северной части Чёрного моря: 1 — Мамайя, Румыния; 2 — северо-западная часть Чёрного моря (СЗ-ЧМ), Крымский сектор; 3 — Севастополь; 4 — Алупка; 5 — Ялта — Алушта; 6 — Карадаг; 7 — Керченский пролив. Сбор рапаны в прибрежной зоне до глубины 15 м проводили тотально с использованием легководолазного оборудования, в более глубоководной зоне (до 40 м) — дночерпателем «Океан-50» с борта НИС «Профессор Водяницкий». Каждый экземпляр помещали в отдельный пластиковый пакет с указанием района, глубины и биотопа. Параллельно со сбором моллюсков проводили визуальные наблюдения и фотофиксацию гидробионтов in situ. Всего проанализировано 890 экземпляров R. venosa. По сравнению с предыдущими исследованиями существенно расширен таксономический список консортных моллюсков R. venosa, относящихся к трём классам: Polyplacophora (Loricata), Bivalvia, Gastropoda. В этой части работы рассмотрены Polyplacophora, представленные в консорции 3 видами 2 родов 2 семейств, и Bivalvia — 7 видами 7 родов 5 семейств. Установлено, что моллюски являются важным компонентом консорции рапаны. На скальной рапане хитоны встречаются с частотой до 25 %, на песчаной рапане — до 10 %, в целом в консорции рапаны — около 12 %. Более 80 % численности всех хитонов на рапане приходится на Lepidochitona cinerea. Встречаемость бивальвий в большинстве обследованных районов составляет 50–75 %. Площадь покрытия раковины рапаны двустворками обычно составляет 2–20 %, иногда достигая 85 %. Наиболее распространённым видом бивальвий и моллюсков в целом в консорции черноморской рапаны является Mytilaster lineatus. Большинство Bivalvia имеют тесную связь с ядром консорции, прикрепляясь биссусом к поверхности раковины рапаны, а на самых ранних стадиях — и к поверхности эпифитов. Представители Polyplacophora приурочены преимущественно к скальной форме рапаны, а Bivalvia представлены большим количеством видов в консорции рапаны рыхлых грунтов, чем скальных (6 против 3 видов соответственно). Различия в таксономическом составе эпибионтов и проценте покрытия раковины двух экоформ R. venosa преимущественно определяются спецификой динамического воздействия водной массы в зонах развития скальных и рыхлых грунтов.

Экологические связи Rapana venosa (Gastropoda: Muricidae) с представителями ихтиофауны в Чёрном море

Мониторинг популяций экологически значимого хищного вида моллюсков Rapana venosa является частью мониторинга Чёрного моря. Значительный интерес представляет изучение роли этого вида в современной морской экосистеме. В июне – сентябре 2015–2016 гг. проводилось изучение консортивных связей рапаны in situ с параллельным отбором проб. В ходе исследований была получена информация о взаимодействии R. venosa с представителями ихтиофауны, расширяющая представления об экологической роли моллюска – вселенца и этологии и экологии нескольких видов рыб.

Habitat Disturbance Combined with Life History Traits Facilitate Establishment ofRapana venosain the Chesapeake Bay

ABSTRACT The veined rapa whelk (Rapana venosa) invasion of the Chesapeake Bay in the United States was first observed in 1998. Chesapeake Bay rapa whelk population demographics, age-at-length relationships, and invasion progression (temporal, spatial) from 1998 to 2009 are described. Between June 1998 and November 2009, 27,624 rapa whelks, ranging from 11- to 195-mm shell length (SL), were collected fromthe lower Bay.Using a Von Bertalanffy age-at-length model (R 2 = 0.99), the 195-mm-SL whelk collected in 2007 was 26 y old, making 1981 the estimated year of first introduction. Age-frequency distributions for Ocean View, Hampton Bar, and the lower James River showed increased whelk numbers per age class and consistent representation of Age 2–3 through Age 7–8 whelks throughout the time series indicating recruitment and establishment. Whelk range expansion into James River oyster habitats began in 2004 and continued through 2009. Whelks occupy shallow areas during warmer months, move into deeper habitats d...

Prey selection and foraging behavior of the whelk Rapana venosa

Rapana venosa is one of the most widespread species of muricid gastropod and lives on all types of substrata. Although common in Bohai Sea, relatively little is known about its ecology specially foraging behavior. We examined (1) prey selection by R. venosa when offered three prey species, Manila clams Ruditapes philippinarum, blue mussels Mytilus edulis and oysters Crassostrea gigas, (2) relative importance of various behavioral components (i.e., encounter, attack, capture and consumption) to the prey selection and (3) in detail the foraging behaviors of R. venosa in the laboratory. Predation rates, prey characteristics (shell strength, energy content per prey, handling time per prey), behavioral components (encounter probabilities, foraging time budget) and major behavioral transition frequencies were analyzed. R. venosa consumed more clams per day than mussels and oysters. Predation on clams was the most effective with a consumption rate of 0.75 clams day−1, although whelks spent only 1.23 % of their time searching for prey. In comparison, 0.54 mussels day−1 were consumed while spending 2.28 % of their time searching, and 0.29 oysters day−1 were consumed occupying 3.08 % of the time. With the preference for clams over mussels and oysters resulted from R. venosa active selection, the prey has a higher profitability. The probability of capture upon attack and consumption upon capture, reflected prey shell strength and morphology, was the two most important behavioral components to determine the prey selection for clams. Searching events took place more often when offered oysters than mussels and clams. Therefore, prey species selection by R. venosa appears to be determined by differences in prey vulnerability and accessibility, and active selection of prey with the highest profitability. Our results have implications for the provision of protective refuges for species of interest (i.e., oysters), such as in population enhancement operations and bottom aquaculture.

Erratum to: Biochemical biomarker responses to pollution in selected sentinel organisms across the Eastern Mediterranean and the Black Sea

Pollution effects were assessed by means of biochemical biomarkers (catalase, glutathione S-transferase and acetylcholinesterase activities, and metallothioneins content) in five species at selected coastal sites across the Eastern Mediterranean and the Black Sea. The mussel Mytilus galloprovincialis, a well-established sentinel species, was investigated in the Adriatic Sea, Aegean Sea, and Black Sea. The mussel Brachidontes pharaonis and the striped red mullet Mullus surmuletus were used in the Levantine Sea where M. galloprovincialis is not present. The white seabream Diplodus sargus sargus and the gastropod Rapana venosa were additionally sampled in the Adriatic and the Black Sea, respectively. Mussels showed catalase, glutathione S-transferase, and acetylcholinesterase responses to pollution in most geographical areas while the response of metallothioneins was restricted to a few sites. R. venosa showed marked responses of catalase and metallothioneins whereas both fish species did not generally exhibit variations in biomarker values among sites. The approach based on the reference deviation concept using the "Integrated Biological Responses version 2" index was useful for the interpretation of overall biomarker responses.

Структура популяций Rapana venosa (Gastropoda, Muricidae) севастопольских бухт (Чёрное море)

Хищный брюхоногий моллюск-вселенец Rapana venosa (Valenciennes, 1846) в настоящее время является важным звеном экосистемы бентали Чёрного моря. Систематический мониторинг его популяций –– неотъемлемый элемент мониторинга Чёрного моря. В летний период 2015 г. проведено исследование популяций R. venosa в четырёх бухтах Севастополя: Голубой, Казачьей, Круглой, Стрелецкой. Определены и сопоставлены основные популяционные характеристики R. venosa. Проанализирован размерный, массовый, возрастной и половой состав популяций рапаны исследованных бухт. На основе полученных сведений дана оценка современного состояния и перспектив развития локальных популяций рапаны этих бухт. Наиболее сбалансирована по структурным показателям локальная популяция рапаны бухты Круглая, которая находится в относительно устойчивом состоянии. Локальные популяции R. venosa в остальных бухтах в разной степени квазиустойчивы. Предполагается, что основным фактором, определяющим структурные особенности популяций рапаны бухт Севастополя, является кормовая база.

Mechanistic studies to evaluate the size dependent toxicity of titanium dioxide nanoparticles (TiO2 NPs) on the soil nematode, Caenorhabditis elegans

In recent years, polybrominated diphenyl ethers (PBDEs) are ubiquitous environmental contaminants, but its bioaccumulation and debromination in biota have remained largely unclear. In this study, we analyzed six PBDEs (BDE47, 99, 100, 153, 154, and 209) in various tissues (i.e., viscera, muscle, and gill) of 11 types of marine organisms including zooplankton, invertebrate and fish. The concentrations of six PBDE including BDE209 in marine organisms ranged from 0.75 to 7.29 ng/g dry weight, BDE209 from 0.46 to 6.78 ng/g dry weight, respectively. BDE209 was the dominant congener in all samples, followed by BDE47. The concentration ratio of BDE47, 99, 154 to ΣPBDEs in various tissues of organisms (i.e., Rapana venosa, shrimp, crab, cuttlefish, octopus, Synechogobius hasta, tonguefish and wolfish) increased, while the concentration ratio of BDE209 to ΣPBDEs decreased. Large differences of the concentration ratios between BDE99 and BDE100 in tissues of crab was found, ranging from 32:68 in crab viscera to 83:17 in crab leg muscle. Biomagnification factors for individual PBDE congeners ranged from 0.16 to 78.6. In general, the BMFs for BDE209 in muscle were higher than those in viscera within feeding relationships. The study results suggesting BDE209 can be biodegraded to BDE47 through BDE154 and BDE99 in marine organism, its metabolite importantly influenced by organism type not trophic level; higher percentage of BDE154 was found in viscera than that in other tissues in the analyzed marine organisms of Bohai Bay.

Transcriptomic Analysis of Differentially Expressed Genes During Larval Development of Rapana venosa by Digital Gene Expression Profiling.

During the life cycle of shellfish, larval development, especially metamorphosis, has a vital influence on the dynamics, distribution, and recruitment of natural populations, as well as seed breeding. Rapana venosa, a carnivorous gastropod, is an important commercial shellfish in China, and is an ecological invader in the United States, Argentina, and France. However, information about the mechanism of its early development is still limited, because research in this area has long suffered from a lack of genomic resources. In this study, 15 digital gene expression (DGE) libraries from five developmental stages of R. venosa were constructed and sequenced on the IIIumina Hi-Sequation 2500 platform. Bioinformaticsanalysis identified numerous differentially and specifically expressed genes, which revealed that genes associated with growth, nervous system, digestive system, immune system, and apoptosis participate in important developmental processes. The functional analysis of differentially expressed genes was further implemented by gene ontology, and Kyoto encyclopedia of genes and genomes enrichment. DGE profiling provided a general picture of the transcriptomic activities during the early development of R. venosa, which may provide interesting hints for further study. Our data represent the first comparative transcriptomic information available for the early development of R. venosa, which is a prerequisite for a better understanding of the physiological traits controlling development.

Incubation Time Required for Hatching, and Ecological Characteristics of the Mode of Life Related with Total Numbers of the Suckers on Each Short Arm of the Hatched Juvenile Larvae of Octopus ocellatus (Cephallopoda: Octopodidae), in Western Korea

The incubation time required for hatching of O. ocellatus were investigated through the processes of egg and embryonic developments by the dissecting microscopic and visual observations. And differences in ecological characteristics of the plankton mode of life or the benthic mode of life according to total numbers of the suckers on each short arm of the hatched juvenile larvae of O. ocellatus were studied by comparisons with other octopodidae species. Compared with the recent a few results reported by other researchers associated with the incubation time required for hatching by female adult mother of O. minor (73-90 days after spawning at 20.9-21.5℃ ranges), in this study, the incubation time required for hatching by female adult mother of O. ocellatus was 56-57 days after spawning at 11.0-20.4℃. Therefore, the incubation time required for hatching by female adult mother varied with Octopodidae species. In this studies, each ovarian egg laid by a female was connected to an egg string attaching to the surface of the wall or bottom of vacunt shell of Rapana venosa. Egg and embryonic developments of this species were studied in the indoor aquaria, in the specific gravity ranging 1.024-1.025. the hatched juvenile of O. ocellatus is 10.3 mm in the mean total length and 4.5 mm in mantle length, and each of its short arms has 18-20 suckers. The just hatched juvenile larvae of O. ocellatus enter the benthic mode of life (benthic larval stage) after hatching. In particular, regarding differences in ecological characteristics of the mode of life according to total numbers of the suckers, O. vulgaris may not need to have many suckers because they enter the planktonic mode of life after hatching, however O. ocellatus may need to have many suckers, because they should adapt to the benthic mode of life. And also the just hatched juvenile larvae of O. minor (bearing many suckers more than O. ocellatus) enter the benthic mode of life (benthic larval stage) after hatching. Therefore, the total number of the suckers on each short arm of the hatched juvenile larvae can be used for determining whether an octopus species has planktonic larval stages or benthic larval stage (benthic mode of life). In particular, The intracohort cannibalism phenomena appeared at the hatched juvenile larval stage because the larval stage of O. ocellatus and O. minor enter into the benthic larval stage in the early stage, unlike entering into the plaktonic larval stage in other Octopus species such as O. vulgaris: at this time, the early hatched larvae fed the late hatched larvae (they are the same species and almost same ages). Therefore, the intracohort cannibalism pheneomena occur in the just hatched juvenile stage of only O. ocellatus and O. minor.

Comprehensive and Quantitative Proteomic Analysis of Metamorphosis-Related Proteins in the Veined Rapa Whelk, Rapana venosa.

Larval metamorphosis of the veined rapa whelk (Rapana venosa) is a pelagic to benthic transition that involves considerable structural and physiological changes. Because metamorphosis plays a pivotal role in R. venosa commercial breeding and natural populations, the endogenous proteins that drive this transition attract considerable interest. This study is the first to perform a comprehensive and quantitative proteomic analysis related to metamorphosis in a marine gastropod. We analyzed the proteomes of competent R. venosa larvae and post-larvae, resulting in the identification of 5312 proteins, including 470 that were downregulated and 668 that were upregulated after metamorphosis. The differentially expressed proteins reflected multiple processes involved in metamorphosis, including cytoskeleton and cell adhesion, ingestion and digestion, stress response and immunity, as well as specific tissue development. Our data improve understanding of the physiological traits controlling R. venosa metamorphosis and provide a solid basis for further study.

Sex and site-specific trends in veined rapa whelk (Rapana venosa) tributyltin bioaccumulation: considerations for biomonitoring

The imposition of male sexual characteristics onto the female (imposex) is present in wild populations of the non-native veined rapa whelk (Rapana venosa) in Chesapeake Bay, USA but does not appear to compromise reproductive function. Cultured whelks were used to test two hypotheses: (1) Observed imposex metrics will be similar to tributyltin (TBT) water concentrations at each of three sites; (2) Male and imposex/female whelks from the same site will have similar TBT body burdens. Cultured 2-year-old whelks were transplanted to three field sites in the York River, USA at the onset of their second reproductive season. Transplant site mean TBT water concentrations ranged from 1.4 ± 0.77 to 64.2 ± 57.8 ng l−1. Imposex incidence was 100% after 28 weeks with an observed M:F:IF ratio of 81:0:92 across all sites. Imposex stages (median vas deferens scale index = 4) and reproductive output were similar across sites. The imposex severity (IS = penis length/shell length) increased with increasing TBT concentrations. The relative penis length (RPLI) and relative penis size (RPSI) indices were positively related to site-specific TBT levels. Male whelks accumulated significantly higher TBT concentrations than female whelks at the site with the highest TBT concentration. Mean TBT concentrations in whelk egg capsules were significantly higher than concentrations in male or female whelk tissue. Egg capsule deposition provides a depuration mechanism for female whelks to reduce body burden of lipophilic TBT. Sex, season and reproductive status should be considered when using gastropod bioaccumulation to monitor TBT effects.

Metabolomic analysis of competent larvae and juvenile veined rapa whelks (Rapana venosa)

Metamorphosis of a planktonic larval stage to a benthic juvenile is an important process in many marine invertebrates including the whelk, Rapana venosa, but understanding of the variety of molecular mechanisms underlying metamorphosis in different invertebrate clades is still poor. The present study examined the metabolic profiles of competent larval and post-larval stages of R. venosa using GC-MS. The whelk egg capsules were collected in Laizhou Bay, Shandong, China, in June 2015, and the larvae and post-larvae were cultured in the laboratory. A total of 263 metabolites were detected, 53 of which had different concentrations in larvae and post-larvae: 29 that were apparently higher following metamorphosis and 24 that were lower. Among the metabolites whose concentrations were higher in post-larvae, quinoline-4-carboxylic acid, the dipeptide cysteinylglycine, and anandamide were the most abundant. The metabolites present in higher concentrations in the competent larvae were a suite of oligosaccharides ( maltotriose, glucose-6-phosphate, cellobiose, and maltose), L-homoserine, adrenosterone, and sarcosine. Although the roles of these and other metabolites in whelk development are not yet completely known, they provide some clues to the changes in energy metabolism and cell signaling that take place during metamorphosis.

FEATURES OF ASSOCIATIVE LINKS BETWEEN NONHOMOLOGOUS ALLELES OF THE GENE-ENZYME SYSTEMS IN DIFFERENT RAPANA GROUPS OF BLACK SEA

Rapa whelk (Rapana venosa, Valenciennes, 1846) has a great influence on the operation of such an isolated marine ecosystem, as the Black Sea. However, many aspects of its vital functioning, including the genetic and biochemical mechanisms of Rapana high adaptive capacity, practically unknown. Therefore, the aim of this work was to find among Rapana genotypes stable combinations (pairings, association) of different alleles of a gene-enzyme systems, the totality of which can be regarded as adaptive gene complexes. The shellfish from waters of the three north-western parts of the Black Sea (Odessa Bay, Tarhankut and island Zmeiniy) were investigated. There were analyzed 169 individuals of a species R. venosa. The homogenates for electrophoretic separation were prepared from gland of Leiblein of molluscs; the identification of allozymes were performed in PAA-gels. The following enzymes were studied: alkaline phosphatase, NADH oxidase, esterase, alcohol dehydrogenase and glutathione peroxidase. The eight loci, including two for next enzimes - alkaline phosphatase, esterase and NADH oxidase were chosen for the testing of genotypes; the alcohol dehydrogenase and glutathione peroxidase were presented by one locus for each enzime. In conducting the genetic analysis based on the hypothesis about the two allel structure of the investigated loci. The presence of conjugation between alleles of different loci, controlling different enzyme systems, determined by the coefficient of association and Russell-Rao coefficient of linkage disequilibrium. It revealed that between certain alleles of enzymes' loci formed temporary association. Specific association of alleles in a population can be kept for several years; this fact may indicate their adaptive value. The example of such combination is a long association between alleles of alkaline phosphatase Alp-126 and the alcohol dehydrogenase Adh03. Number of associated alleles of the gene-enzyme systems to a certain Rapana group due to the general state of the animals in the waters: the largest number of complexes between alleles of gene-enzymes systems were observed in a set of Odessa Bay Rapana individuals (grouping in good condition), the lowest - in Tarkhankut waters (grouping in the doldrums). It is suggested that the role of the alleles in the adaptation of associations: negomologinih found temporary combinations of alleles can act as a source of adaptive gene complexes. It is suggested that the role of the alleles associations is important for the adaptation : detected temporary combination of non-homologous alleles can act as a source of adaptive complexes

New source of chitosan from Black Sea marine organisms identification

ABSTRACTThe Romanian Black Sea environment, due to its biodiversity, contains a lot of organism, which represents a rich natural resource of many biologically active compounds, such as: sterols, proteins, polyunsaturated fatty acid, polysaccharides, pigments and antioxidants.In their evolution, marine organisms in the Black Sea adapted excellently to the marine environment such as: low temperature, absence of light, extreme pH and pressure, low salinity, low oxygen, the presence of one toxic abiotic chemical (H2S). Moreover, they produce a wide variety of secondary metabolites (biologically active), which cannot be found in other terrestrial organisms.Chitosan is a copolymer of β-(1→4)-linked 2-acetamido-2-deoxy-D-glucopyranose and 2-amino-2-deoxy-D-glucopyranose. Usually, it is obtained by deacethylation of the natural chitin, which is extracted from the exoskeleton of marine organisms, mainly crabs and shrimps. Chitosan could have a lot of applications in biomaterials, pharmaceuticals, cosmetics, metal ion sequestration, agriculture and foodstuff treatment (flocculation, clarification) because of its efficient interaction with other polyelectrolytes.In this paper, we propose new possible source of chitosan, the spawning of Rapana venosa, a predatory gastropod, which invaded the Black Sea in earlier 1940s. Preliminary spectral studies on this biopolymer extracted from this biomaterial and another marine source (Eriphia verucosa) will be discussed and compared with that of chitosan standard in order to put in evidence the presence of chitosan in the obtained extracts.

Metal Concentrations in Sediment And Biota of the Huludao Coast in Liaodong Bay and Associated Human and Ecological Health Risks.

This study assessed the contamination extent and potential ecological and human health impacts for chromium (Cr), manganese (Mn), nickel (Ni), copper (Cu), zinc (Zn), cadmium (Cd), and lead (Pb) in sediments and indigenous benthic organisms along the coastal area of Huludao, China. We analyzed a total of eight species: two benthic fish species, two bivalves, two snails, and two decapod crustaceans. Cu, Zn, and Cd levels in sediment exceeded the Chinese marine sediment quality criteria. The geoaccumulation index was highest for Cd followed in a decreasing order by Zn, Pb, Cu, Ni, and Cr. Metal levels were highest in the four mollusk species. The oyster and veined rapa whelk had the highest bioaccumulation factors, indicating that these two species would be well suited for monitoring the metal pollution in this area. Our comparison of estimated daily intake values for human consumption of the seafood species to the Food and Agricultural Organization-recommended daily dietary allowances indicate potential health risks from the intake of Cd from all shellfish other than our crab species and Zn intake from oyster consumption. An analysis of target hazard quotients identified noncarcinogenic health risks from Cd (in all shellfish analyzed except for our crab species), Cu, and Zn (in oysters and veined rapa whelks). Moreover, an analysis of cancer risk from Pb ingestion detected an increased risk for consumption of all shellfish except for the crab species. Health risks seem especially pronounced for the consumption of oysters and the veined rapa whelks; a seafood advisory may be warranted for these mollusks.

Особенности активности ферментов энергетического обмена в тканях черноморских моллюсков разной подвижности в норме и при патологии

Одним из важнейших показателей метаболизма у моллюсков является активность ферментов энергетического обмена ― лактатдегидрогеназы (ЛДГ, 1.1.1.27) и малатдегидрогеназы (МДГ, 1.1.1.37), неизменно участвующих в адаптационных перестройках. Целью работы было сравнение активности ферментов энергетического обмена в тканях черноморских моллюсков с различными эколого-физиологическими особенностями. Объектами исследования служили половозрелые моллюски Mytilus galloprovincialis, Flexopecten glaber ponticus, Аnadara kagoshimensis и Rapana venosa в нерестовый период. Длина раковины мидии составляла 50–55 мм, анадары ― 25–33 мм, рапаны ― 50–80 мм, флексопектена ― 35–54 мм. Активность ферментов измеряли спектрофотометрически (при 340 нм and 25 ºC) по скорости окисления НАД-Н в цитоплазме тканей. Максимальная активность ЛДГ и МДГ у мидии, анадары и рапаны установлена в мышечной ткани, минимальная ― в гепатопанкреасе. Уровень активности МДГ в ноге, аддукторе, жабрах и гепатопанкреасе двустворчатых моллюсков-фильтраторов мидии и анадары достоверно выше, чем ЛДГ. Наибольшей активностью МДГ характеризовались ткани устойчивой к гипоксии анадары. Активность ЛДГ и МДГ в однотипных тканях хищного моллюска рапаны существенно не различалась. Показано, что активность ЛДГ в гепатопанкреасе, жабрах и мышечной ткани пропорциональна подвижности вида и увеличивается в ряду мидия ― анадара ― рапана. У Flexopecten glaber ponticus, собранного в зоне сброса воды с рисовых чеков и пораженного перфораторами, тканевая специфика активности ЛДГ и МДГ была нарушена, уровень активности ферментов понижен и не соответствовал естественной подвижности вида. Обсуждено состояние здоровья черноморского гребешка, находящегося под угрозой исчезновения в дикой природе.

Influences of population density on polyandry and patterns of sperm usage in the marine gastropod Rapana venosa.

Polyandry is a common mating strategy in animals, with potential for sexual selection to continue post-copulation through sperm competition and/or cryptic female choice. Few studies have investigated the influences of population density on polyandry and sperm usage, and paternity distribution in successive broods of marine invertebrates. The marine gastropod Rapana venosa is ideal for investigating how population density influences the frequency of polyandry and elucidating patterns of sperm usage. Two different population density (12 ind/m3 and 36 ind/m3) treatments with two replications were set to observe reproductive behaviors. Five microsatellite markers were used to identify the frequency of multiple paternity and determine paternal contributions to progeny arrays in 120 egg masses. All of the mean mating frequency, mean number of sires and mean egg-laying frequency were higher at high population density treatment relative to low population density treatment, indicating population density is an important factor affecting polyandry. The last sperm donors achieved high proportions of paternity in 74.77% of egg masses, which supported the “last male sperm precedence” hypothesis. In addition, high variance in reproductive success among R. venosa males were detected, which might have an important influence on effective population size.

First documentation of the barnacle Fistulobalanus albicostatus (Cirripedia: Balanomorpha) as an epibiont of loggerhead sea turtle Caretta caretta

Epibionts on a nesting female loggerhead sea turtle Caretta caretta (Linnaeus, 1758; 92.1 cm straight carapace length and 70.7 cm straight carapace length) were examined on the island of Yakushima, Kagoshima, Japan (30.4156°N, 130.4394°S) on 16 June 2009 (Fig. 1a). Specimens were photographed, counted and identified at the lowest taxonomic level, and four species of barnacles were found: Chelonibia testudinaria (Linnaeus, 1758), Platylepas hexastylos (Fabricius, 1798), Stephanolepas muricata Fischer, 1886, and Fistulobalanus albicostatus (Pilsbry, 1916). The turtle barnacles C. testudinaria (n = 6), P. hexastylos (n = 42) and S. muricata (n = 1) are common on Japanese turtles (Hayashi 2012), while this is the first record of F. albicostatus (n = 4) on sea turtles. The acorn barnacle F. albicostatus is a common species in estuaries and mangroves and as a biofouling species on ships, and occurs in the waters of Japan, China, Taiwan and Korea (Newman and Ross 1976; Chan 2007). The barnacle has also been recorded in California waters as an invasive species (Bonnot 1935; Henry and McLaughlin 1975). Japanese loggerhead turtles migrate over the Pacific Ocean as developmental migration in their ontogenetic stages (Bowen et al. 1995); sea turtle migration allows F. albicostatus and possibly other organisms biofouling sea turtles to invade new habitats, as seen in a case of rapa whelk Rapana venosa (Valenciennes, 1846) recorded in Harding et al. (2011). In one example for F. albicostatus, a new geographic expansion into Norway by biofouling plastic tags on migrating birds was reported (Tottrup et al. 2010). Further studies are needed to examine the potential role of migratory animals such as sea turtles and birds as dispersal vectors of these hitchhikers.

Seasonal variations in biochemical composition during the reproductive cycle of the veined rapa whelk Rapana venosa (Valenciennes, 1846) from the northern coast of China

ABSTRACTSeasonal variations in the biochemical composition of Rapana venosa in relation to reproductive cycle and environment on the northern coast of China were investigated from March 2012 to February 2013. The results indicated that R. venosa has an annual reproductive cycle with synchronized gonad development in both females and males. Gametogenesis was initiated in September and gametes developed slowly during the winter, followed by rapid gonad development during spring and summer. Most individuals from this study were sexually mature between May and June, and gamete release occurred mainly between May and August. The peak of spawning was found in July and the recovery of the gonad was observed between August and November. The key biochemical components including glycogen, protein and lipid were analysed in four tissues, specifically the gonad, digestive gland, mantle and foot. The declining glycogen content in the gonad, digestive gland and mantle during maturation suggested that glycogen was consumed during the development of the gonad. Lipids and protein can be stored in the digestive gland and used during the winter in a period of food shortage. The protein and lipid contents in the ovaries increased during gonad development, which suggested that the protein and lipid had been accumulated as vitellin in oocytes.