Biological data were collected in a Patagonian scallop fishing ground, between 39° 00′ and 39° 50′ S and between 87 and 130 m depth. During 2007, we sampled the following stations where the trawling exerted could be precisely determined: 11 locations subjected to continuous fishing effort between 1996 and 2006 (continuous fishing effort, 878 commercial tows) and 12 locations subjected to fishing effort between 1996 and 2002 (interrupted fishing effort, 302 commercial tows). Univariate (species richness, Shannon's diversity index, and Pielou's equitability index) and multivariate analysis, analysis of variance, and Kruskal—Wallis tests were applied to analyze species composition and biomass. This study reflects the significant higher density of sessile taxa (Porifera and the ascidean Paramolgula gregaria) and two small ophiuroids (Ophiacantha vivipara and Ophiura lymani), all of them conspicuous during the exploratory cruises conducted in 1995, in the sites where fishing effort was interrupted 4 y before the sampling in 2007 than in those sites continuously exploited and discusses the results considering previous knowledge on the damage that the process on board scallopers imparts on invertebrates bycatch.

In the spring of 2007, a small number of empty valves from the bay scallop, Argopecten irradians irradians (Lamarck), were observed at several locations in Pomquet Harbour, Nova Scotia, Canada. Snorkeling surveys at selected sites in the harbor were carried out in spring 2007, summer 2007, and spring 2008. Scallop densities were very low in all sampling times, ranging between 0.04 and 0.053 scallops/m². The size distributions from 2007 suggested a single cohort of 0 individuals, with one 1 scallop. The 2008 samples were predominantly 1 scallops, with five 0 individuals. Four marked scallops from 2007 were collected alive in 2008, demonstrating their ability to overwinter. These scallops had an average daily growth rate of 0.08 mm/day from July 2007 to May 2008. A thermistor deployed in the same eelgrass beds indicated that the scallops survived extended periods of time with temperatures below 0°C. In 2013, four of the sites were surveyed again, and dramatic increases in density were recorded, averaging 1.713 scallops/m². The bay scallops in Pomquet Harbour probably represent an incidental introduction, as larvae, from aquaculture operations ∼80 km to the north.

The authentication of seafood origin is essential to establish a reliable product traceability system. In principle, appropriate markers can confirm the product origin without additional information. Scallop is an important shellfish product around the world. Its nutritional quality can be closely related to several environmental factors and varies between different habitats, yet it is not known if quality variation can be a reliable marker indicating product origin. In this study, the regional quality characteristics of scallop (Argopecten irradians) harvested from 18 farms in the North China Sea was investigated. Seven nutritional indices (moisture, ash content, sugar, crude protein, ω;3 polyunsaturated fatty acids, condition index, amino acid chemical score) show considerable geographic differences. Based on quality composition data, cluster analysis demonstrates three different scallop product origins: those from the North Yellow Sea and Bohai Sea, Middle Yellow Sea, and Laizhou Bay. Fatty acid biomarkers reveal that quality variations are caused by regional differences in pelagic food sources. Results suggest that nutritional quality indices could be a potential marker to indicate geographic sources of cultured scallop.

The Pacific geoduck Panopea generosa is distributed along the Pacific coast of the peninsula of Baja California, Mexico. Because of its high market value, this species has been under an intensive fishery pressure during the last few years, whereas its experimental aquaculture production is still developing. The fishery and culture practices point to the movement of clams as a risk factor for dispersion of symbionts, parasites, and diseases. Wild geoduck clams from fishery captures are sent to facilities that maintain clams alive, before marketing. Some of them show external abnormalities such as weakness and flaccidity, blisters, and darkening and thickening of the mantle surface and siphon. The objective of this study was to determinate if these abnormalities were related to parasites or diseases through conventional parasitological and histological analyses. The parasitological analysis showed two species of copepods, Pseudomyicola spinosus and a calanoid species in the mantle cavity and gills; additionally, a turbellarian species was also observed in the mantle cavity, none of these symbionts were related to tissue damage. The histological analysis showed that some weak-flaccid clams were in a postspawning condition. The dark and thick areas of the siphon and mantle suffered a dramatic transformation of the periostracum into a cavernous structure with numerous protozoans in different developmental stages. Fungi were occasionally observed in the external area of the periostracum. Unusual mortalities were reported by producers in clams with this abnormality. Rickettsia-like inclusions and trematodes were found in the digestive gland associated with limited damage to the host. The darkening and thickening of the siphon represent a major issue because of the negative appearance of the clams, which prevents its sale and is possibly related to the unusual mortality episodes. Detailed field and laboratory studies are needed to determine the origin of this pathology as well as its distribution and effect on the survival of the host. Moreover, field studies on the distribution, prevalence, and intensity of the other symbionts and parasites here detected are needed. These data constitute the first record for organisms associated with P. generosa in Mexico and a baseline for future studies.

The Pacific geoduck Panopea generosa is the largest burrowing clam in the world and adults can live up to a meter below the sediment surface. To extract these clams, harvesters use pressurized water jets to dislodge surrounding sediments. This type of disturbance could have significant effects on the local benthic environment, but has been little examined. The present study was conducted on one intertidal and one subtidal plot to assess potential effects of commercial-scale geoduck harvesting on the sedimentary benthic environment and nearby eelgrass beds. Sediment samples were collected inside the impacted plots and at intervals up to 75 m away while eelgrass sampleswere collected adjacent to the impacted plots and at intervals up to 50maway, seasonally over 2 y.Harvest of the subtidal plot occurred at one year and mock harvest of the intertidal plot occurred after one preimpact sample. Sediment and infaunal qualities examined included: grain size, percent organics, total nitrogen, total organic carbon, sulfide content, redox potential, and infaunal community structure. Eelgrass parameters studied included shoot length, shoot density, and biomass. Sedimentation rates during harvesting were examined and compared with those of natural occurrence. Suspended sediments were increased by harvesting, but generally limited to the footprint of the harvested area, and were not greater than those created by wind/storm conditions. No changes were observed, however, in any of the measured sediment or infaunal variables on or near the harvested plot or in adjacent eelgrass. In addition, no significant response in eelgrass parameters was observed. This study indicated little effect of commercial geoduck harvesting practices beyond short-lived resuspension of sediment on the two harvested plots.

The reproductive cycle of the large trough shell Mactra murchisoni (Deshayes, 1854) from Pegasus Bay, New Zealand, was examined between March 2013 and February 2014. Histological analysis indicated that M. murchisoni is dioecious (there were no observed hermaphrodites) and gametogenic development is synchronous between the sexes. Gonadal development began in May in both male and females, with the first ripe individuals observed in June and July for male and females, respectively. Spawning began in spring, peaking in late summer with resorption taking place around autumn. No resting samples were observed. Condition indices were calculated each month and were at their highest during the period individuals were ripe. These indices were significantly different (P < 0.05) between the majority of months and indicate that a high portion of individuals' mass was gonadal tissue during ripe periods. Finally, the results displayed parity between the sex ratio (P =0.2782), reinforcing that the species are dioecious.

The yellow clam Amarilladesma mactroides (Reeve, 1854), is an intertidal species that prospers mainly on dissipative sandy beaches along the temperate Atlantic coast of South America, from Brazil to Argentina (24–41° S). This large clam is considered a fast burrower, which lives buried in the sediment, migrating seasonally into the intertidal zone. The present study explores the effect of sediment grain size on the burrowing performance of this species, to elucidate the influence of granulometry on the alongshore distribution of the A. mactroides population. Laboratory trials were performed with clams of different sizes, to study the influence of grain size on the burial rate. Clam distribution was analyzed along a 32 km coastal fringe whose granulometric composition varies from very fine to coarse sand. The values of the mean burrowing rate index, a measurement of clam mobility, suggest that burrowing is fast to very fast in fine and medium sand and becomes slower toward areas with extreme particle size (very fine and coarse sand). The burial time of A. mactroides was positively correlated with shell length: small animals can burrow into substrates that may exclude larger animals. Adults clams burrowed in a very limited range of sand grain sizes. They displayed fastest burial times in grain sizes typical of dissipative beaches, i.e., fine to medium sand. Patchy distribution and density variation of A. mactroides alongshore reflect the relation between grain size and burrowing performance: the population is absent in sites with the highest proportion of coarse sands, its density increases in patches with the highest proportion of fine and medium sand and peaks at a site with the highest proportion of fine sand. Results indicate that the discontinuous distribution of A. mactroides along its range could be due to a postsettlement process. Clams can potentially recruit on a wide morphodynamic range, but only may thrive in beaches which sand grain size allows them a rapid reburial during migratory and local movements.

Genetic variation was investigated using allozymes, cytochrome c oxidase subunit I, internal transcribed spacer region 1, and microsatellite markers in mainland and insular populations of the carpet shell Ruditapes decussatus from the western and eastern Mediterranean Basin. Five morphometric parameters and weight of valves were also used to study the distribution of variation within and among populations. The species is characterized by a relatively high inter- and intrapopulation morphological and genetic variability. The highest values of percent polymorphism and heterozygosity (allozyme and microsatellite data) were found in the sample from Kerkennah Island. The occurrence of higher levels of genetic variability in insular population is probably because this population inhabit marginal environment characterized by temporal-ecological instability. The genetic heterogeneity analysis demonstrates a certain amount of genetic differentiation among local populations of R. decussatus with a relatively high level of genetic subdivision. Sample from Kerkennah Island was differentiated from almost all other populations. Kerkennah Island clams are also the most different in morphology. This study was intended to elucidate, from genetic markers and morphometric parameters, the relative importance of the biogeographical properties of islands on the observed patterns of differentiation of the Kerkennah population.

The vasa orthologs have been used as a specific germ line molecular marker in many animal species. In this study, the expression of the vasa ortholog (povlg1) in adult and juvenile pearl oysters (Pinctada fucata) was observed by in situ hybridization. The in situ hybridization with povlg1 made it possible to detect the immature germ cells, which could not be detected by hematoxylin and eosin staining. During the reproductive season (May to July), spermatogonia, spermatocytes, oogonia, and oocytes showed povlg1 expression in the gonads of mature adult pearl oysters. By contrast, in spent pearl oysters in the nonreproductive season (September and October), only small ovoid (8.9×5.2 mm) povlg1-positive cells were observed in the base of acini. In juvenile (1 mo old) pearl oysters, a clump of germ cells first formed from several cells that were distributed symmetrically and lateral to the visceral mass. These cells then migrated to the ventrolateral periphery of the visceral mass in 2-mo-old oysters. The cells then migrated posteriorly along the periphery of the visceral mass with increasing cell numbers and size in 4-mo-old oysters. This observation of immature germ cell distribution and migration provides useful information for the control of gametogenesis and about pearl quality.

The black-lipped pearl oyster Pinctada margaritifera is of high economic importance in French Polynesia.Arecent decline in pearl value led to the initiation of several genetic breeding programs aiming to improve production traits, including oyster shell growth, which dictates the time of grafting, size of the implanted nuclei, and biomineralization capacities. We assessed shell diameters on hatchery-produced spat to analyze juvenile growth performance of four half-sib families derived from polyandry (one dam crossed with two sires) and polygyny (two dams crossed with one sire) using gametes obtained by thermal shock or gonad scarification. Spat growth was monitored over 3 mo, with shell diameter measured weekly. Results revealed that the spawning method had no significant effect on juvenile growth; however, the half-sib families produced with the polygyny mating design showed significant differences in average shell diameter between dams throughout the experiment, whereas none were observed between sires with the polyandry mating design. Precocious larval size selection within each family was performed by separation into batches of small, medium, and large size, and their maintenance through juvenile stages, providing the possibility for early growth selection. These findings are important for genetic breeding programs (1) as breeding of sires and dams exhibiting the most colorful inner shell phenotypes would be possible with the gonad scarification spawning procedure without affecting overall growth performance and (2) because P. margaritifera is a protandrous hermaphrodite species, genetic selection strategies in the pearl industry must take into account the differential influence of polygyny and polyandry mating designs.

Oysters provide habitat, sediment stabilization, and improved water quality, and are important foundation species in many estuarine ecosystems. Worldwide oyster population declines have been dramatic and efforts to restore declining populations and the services they provide are ongoing. Several commonly used oyster restoration techniques were examined to determine which would be the most successful for restoring the Olympia oyster Ostrea lurida in Newport Bay, CA. Replicate (n = 5) 2×2 m shell beds were constructed of two initial shell planting thicknesses (bed thicknesses of 4 versus 12 cm) and two methods of deployment (bagged versus loose shell). Shell cover, oyster spatfall (settlement), oyster recruitment, and adult oyster densities were analyzed over 2 y; 12-cm-thick oyster beds maintained higher shell cover, experienced less sedimentation, and received greater numbers of oyster recruits than 4-cm-thick beds. There was no significant effect of shell deployment method on shell cover, recruitment, or adult density; however, spatfallwas greater on loose shell beds comparedwith bagged shell beds in the final year of the study. Overall, augmenting mudflat habitat with oyster shell significantly increased adult O. lurida oyster density compared with unmanipulated plots and increased oyster density relative to the average density of oysters measured elsewhere in Newport Bay. Collectively, the data suggest that building thicker shell beds might increase the longevity of a constructed shell bed, and therefore, this approach is recommended for future restoration activities in southern California. This study highlights the advantages of augmenting habitat in a manner that provides vertical relief from sedimentation.

Physiological characteristics of gametogenesis, fertilization, and early larval development in Ostrea chilensis (Philippi, 1845) pose a number of challenges for selective breeding, despite strong commercial potential. In wild populations, this larviparous protandric hermaphrodite exhibits asynchronous gonadal maturation and relatively low fecundity. Reproductive success and genetic diversity in a hatchery population are primarily determined by female fecundity and fertility, as well as synchrony of female gonad development. Better hatchery control of the reproductive cycle can lead to more cost-effective and reliable breeding. This study examined factors such as feed and temperature in an attempt to increase reproductive rates and female sex ratios in brood stock. Oysters held under two different hatchery conditioning regimes—flow-through outdoor nursery ponds and temperature-controlled indoor tanks—spawned earlier and had higher reproductive rates than natural or farmed populations. Oysters were sampled over 6 months with histological analysis used to assess seasonal gamete patterns. Magnetic resonance imaging was also trialed and compared with histology findings. Significant increase in female gonad proportion and improved synchrony of egg maturation was observed through manipulation of feed and temperature. The implications of these findings for implementing a cost-effective selective breeding program in this species are outlined.

The correct identification of oyster species is essential for both aquaculture and taxonomic study, but it has often been a challenging task due to enormous morphological variation in shell morphs with ecophenotypic origins. The difficulty of species identification based entirely on shell characters has raised the need for developing an accurate, rapid tool for the identification and discrimination of oyster species. In this study, a DNA microarray-based identification system was established for eight commercially important oyster species (Crassostrea ariakensis, Crassostrea gigas, Crassostrea sikamea, Crassostrea nippona, Crassostrea angulata, Ostrea circumpicta, Ostrea denselamellosa, and Saccostrea kegaki). Sixteen species-specific probes developed in this study unambiguously distinguished eight target oyster species with no false-positive or false-negative signals. Of the eight oyster species examined, three Crassostrea species, C. angulata, C. gigas, and C. sikamea, which are indistinguishable by morphology, could be precisely identified using species-specific hybridization probes. The DNA microarray-based identification system developed in this study offers a very effective and reliable tool for eight oyster species, most of which are of commercial value and/or ecological significance in the macrobenthic community of offshore marine environments.

On sea farms, oysters are constantly submitted to mechanical manipulation through size sorting and cleaning of epibionts, and also are maintained out of seawater and exposed to air and sunlight radiation during cleaning and transport to marketplaces. Therefore, the aim of this work was to evaluate gender differences and short-term changes in the immune response, glucose plasma levels, and Hsp70 gene expression in oyster Crassostrea corteziensis exposed for 0 (control), 15, 30, 45, and 60 min to mechanical (agitated), thermic (sunlight), and a combination of both stressors. Variations in total hemocyte count (THC) and granulocyte count (GC), as well in functional characteristics [i.e., mortality of hemocytes, phagocytosis, and anion superoxide production (SOA)] of hemocytes, suggest that oysters seems well adapted to mechanical disturbance, because SOA values increased, phagocytic activity was not affected, and hemocyte counts and mortality were rapidly recovered. Contrary with prolonged exposure of oysters to thermic conditions, which exerted a constantly increase of THC, whereas both hemocyte mortality and phagocytic activity decreased, but oxidative capacity (i.e., SOA) decreased in male and increased in female oysters. Immune competence and Hsp70 gene expression were significantly diminished in oysters exposed for 30 min to a combination of both stressors (i.e., mechanical and thermic), indicating the most vulnerable stress conditions. Hsp70 gene expression showed that females were more susceptible than male oyster to short-term (i.e., 15–30 min) exposure to mechanical and thermic stresses, but prolonged (i.e., 60 min) exposure of combined stressors exerted a particular effect on male oysters. The immune responses assessed and glucose levels in plasma demonstrated that thermic and mechanical—thermic stress conditions were more stressful than mechanical disruption, and that females were more susceptible than male oysters to stress conditions assayed. These environmental and anthropogenic stressors should be considered for the cultivation of this oyster species, as well for further research related with immune response of C. corteziensis.

The eastern oyster [Crassostrea virginica (Gmelin, 1791)] is an important epibenthic species in estuarine and coastal marine ecosystems, providing habitat for commercially valuable species and enhancing ecosystem function. One way to assess oyster population structure and the potential suitability of oyster restoration sites is through deployment of adult oyster shells or other substrates, and quantifying oyster spat settlement. The suitability of travertine tiles versus axenic adult oyster shells for C. virginica settlement was compared by deploying shellstrings with tiles and shells in four different locations across two seasons (fall or spring) in the subtropical, Loxahatchee River estuary, FL. There was no significant difference in spat densities on oyster shells compared with tile tops and bottoms, although there was significant spatial and temporal variation in spat settlement. Spat were slightly more abundant on the top of deployed tiles compared with the bottom, which differs from typical C. virginica settlement behavior. One possible explanation may be the presence of other fouling organisms on the bottom of tiles which decrease oyster settlement rates. Results show that oyster spat settlement was indistinguishable between travertine tiles and oyster shells and thus suggest that travertine tiles are preferable to axenic oyster shells because spat settlement can be precisely quantified per unit area.

Practical and aggressive programs were developed and implemented that enhanced the productivity of two oyster industries, whose landings had been declining for many years. One industry was in Connecticut-New York, Long Island Sound, and the other was on Prince Edward Island (PEI), eastern Canada. Both industries were far smaller than they had been and were in a state of degradation. The programs featured identification of factors that limited oyster abundances on the beds, and then taking immediate steps to reduce their effects. They also featured using information and ideas from the oyster managers in Connecticut, and oystermen and public fisheries officials on PEI. The programs included observing the beds and oysters using scuba. The Connecticut beds received too few shells to collect seed oysters, and mortalities of seed were high. The oyster beds on PEI had been scarcely cultivated. The restoration program in Connecticut lasted for 5 y, 1966 to 1970, and on PEI was for 1 y, 1972 to 1973, but it continued afterward. The Connecticut oysters increased in abundance when oystermen effectively spread more shells to collect seed and reduced mortalities of the seed by controlling starfish Asterias forbesi (Desor, 1848), oyster drills Usosalpinx cinerea (Say, 1822), and Eupleura caudata (Say, 1822), and ‘‘winter-kill.'' The Connecticut-New York landings rose from 62,000 bushels in 1965 to 348,000 bushels in 1975, an increase of 5.6-fold. On PEI, surveys found large quantities of oysters in nonharvested locations and also large deposits of fossil oyster shells. The island's first oyster-dredging boat was constructed to transplant oysters and shells to previously barren bottoms for oystermen to harvest. During the summer of 1973, a total of 53,000 bushels of oysters and shells were transplanted. Prince Edward Island oyster landings increased from 17,000 bushels in 1972 to 97,000 bushels in 2005, a 5.7- fold increase. Individual PEI oystermen did not increase their harvests substantially, but employment in the industry increased from about 200 to 500–700 men over that time. The two programs showed that oyster abundances and their landings can be raised rapidly in oyster industries under both private and public control by following their approaches that feature solving immediate production problems and using a holistic management approach.

Stable isotopes (δ¹³C, δ¹⁵N) were used to assess differences in the diets of wild adult Haliotis fulgens and Haliotis corrugata. Temporal variations in the diets of these species were compared using specimens collected monthly during one annual cycle in Laguna La Bocana, whereas comparisons were made with samples taken in October 2012 in Bahía Tortugas. The two species of abalone have different feeding habits year round; H. corrugata showed a constant d15N pattern (between 9.5‰ and 10.4‰), whereas H. fulgens exhibited a seasonal δ15Npattern [the lowest frequency (9.5‰) occurred in September and the highest (11.8‰) in December], which might indicate that this species fed on the resources that were available at the time. The d13C pattern showed that Laguna La Bocana had depleted values in relation to Bahia Tortugas, indicating different carbon sources. The fact that the d15Npattern of abalone was below the known food sources (macroalgae), suggests the presence of other sources in the diet of adult abalone, such as detritus or epiphytic diatoms.

Because of the nocturnal and slow feeding activity of abalone, farmed abalone are typically provided with feed throughout the night. Understanding the nocturnal feeding patterns of abalone is fundamental to feed management and productive abalone farming. In this study, the apparent feed consumption for greenlip abalone (Haliotis laevigata) and hybrid abalone (H. laevigata3Haliotis rubra) fed fresh Ulva sp. or a commercial formulated diet at 18°C or 22°C were investigated at night. Abalone were exposed to low light intensity (3.4 Lux) from 7:00 AM to 7:00 PM and darkness from 7:00 PM to 7:00 AM. Abalone were fed to excess daily at 4:00 PM and feed intake was determined at 7:00 PM, 10:00 PM, 1:00 AM, 4:00 AM, and 8:00 AM. When Ulva sp. was added to the tank, greenlip and hybrid abalone immediately displayed a feeding response, which was not observed in abalone fed the formulated diet. Abalone consumed Ulva sp. at a linear rate from 4:00 PM to 8:00 AM. In contrast, the apparent feed consumption rate of abalone fed the formulated diet was minimal from 4:00 PM to 7:00 PM, and was highest between 7:00 PM and 1:00 AM. Apparent feed consumption rate of abalone significantly increased as water temperature increased from 18°C to 22°C, but the effect was greater for hybrid abalone compared with greenlip abalone. The total apparent feed intake of both greenlip and hybrid abalone fed Ulva sp. was significantly greater than for both types of abalone fed the formulated diet. The total apparent feed intake on dry basis, and nutrient intake for abalone fed Ulva sp. was significantly lower than for abalone fed the formulated diet. This study indicates that the upper temperature range for feed intake in hybrid abalone is higher than in greenlip abalone. Ulva sp. can stimulate abalone feeding, though the high moisture content in algae can reduce nutrient intake.

Changes in the morphology of the radula in the giant key-hole limpet (GKL) were analyzed including radula length, width, number of rows, and the morphology of the teeth in each row through ontogeny. In postlarvae with a shell length (SL) of 700 mm, the radula is ∼240 mm long and composed of about 30 rows of teeth. Each row has a central rachidian tooth, which has a pointed tip similar to the three pairs of lateral teeth on either side. These are flanked by five pairs of marginal teeth. In GKL with an SL of ∼2 mm, the teeth are larger, the rachidian tooth no longer has a triangular tip and lies flat along the radular ribbon except for a curled cusp. The most distal lateral tooth is larger than the other lateral teeth and has a sharply pointed tip, and the number of marginal pairs has increased from 18 to 20. InGKLwith an SL of 6–8 mm, the radula is∼2mmlong. The large, flat rachidian tooth overlaps and covers the laterals except the fifth lateral, which is now much larger and tapers to a sharp point. By the time GKL have an SL of 11 mm, the radula is about 3 mm long and tooth morphology is the same as in larger animals except for a gradual increase in tooth size and differentiation of the marginal tooth tips into three varieties. Scanning electron microscopy with energy-dispersive X-ray spectroscopy demonstrates that the radula is not mineralized and signs of wear and breakage are common on teeth in the first five to seven rows, the rows that are actually extended out of the mouth during a feeding motion.

This study examined the scaling of the radula of the Atlantic slippersnail Crepidula fornicata with body size. As a suspension feeder, the prediction was that the radula may be more important (longer relative to body size) for younger animals, as younger animals are likely to also graze the benthos whereas adults primarily suspension feed. Smaller snails had a disproportionately longer radula than larger snails, likely reflecting a more important role of the radula when animals are small. Furthermore, the radula of C. fornicata is short compared with its body size among caenogastropods. This small radula to body length ratio would be expected if the radula is not used for grazing, except possibly in smaller snails.

Alterations of the cell-mediated and humoral immune parameters were revealed in the bivalves Modiolus kurilensis from the Sea of Japan after injection with heat-inactivated Staphylococcus aureus. Preliminary screening of the in vitro phagocytic activity (PA) and hemagglutination (HA) enabled to obtain homogeneous groups of individuals for all of the parameters to be measured. Changes in hemolymph parameters were studied over a 14-day period. High values for hemolytic activity (HL) and protein concentration (PC) persisted until 36 h, with high levels of HA persisting until 168 h. The in vitro PA level was low from 3 to 6 h postchallenge, which was caused active in vivo hemocyte elimination of the injected antigen in the first 12 h. A significant increase in the in vitro PA up to 36 h was related to a rise in the circulating total hemocyte concentration (from 6 to 12 h) and to in vivo S. aureus clearance (in the first 48 h). For the first time, a complex correlation analysis of the interplay between the cellular and humoral parameters against bacterial challenge in a bivalve revealed significant inverse correlations of PA with HL and HA during the period of these active immune responses from 3 to 48 h. The investigated immune parameters can serve as effective methods for estimation of the physiological state of the bivalve in natural and aquacultural populations under normal environmental conditions and significantly alterations under conditions of stress.

The aim of the present work is to increase the general knowledge about an economically important mussel species in Chile. Species of Mytilus are present in the southern cone of South America; however, there is still some controversy about species identification of samples from this area. The study herein presented attempts to: (1) corroborate the phylogenetic hypothesis defined for the Mytilus edulis species complex including taxa from a worldwide distribution; (2) evaluate the possible presence of the species Mytilus trossulus along the Chilean coast and determine if M. trossulus hybridizes with the local species; and (3) provide detailed data collected along the Chilean coast to help define the taxonomic status of Mytilus in South America. To this end, exhaustive sampling was conducted; Mytilus was collected from the Chilean coast and from the coasts of Argentina and Uruguay. Phylogenetic analysis and genetic divergence estimators were used to compare 426 Cytochrome oxidase I mitochondrial gene sequences and 190 16S RNA sequences of Mytilus species sampled from around the world. Following this, the time of divergence between northern hemisphere and southern hemisphere clades of Mytilus species was estimated. In addition, neither M. trossulus nor any associated hybrids were found along the Chilean coast. Finally, the identification of samples from the southern cone of South America is discussed including whether the samples should be identified as Mytilus planulatus or Mytilus platensis. In accordance with the taxonomic priority rules and the results presented here, the species identification frequently used in the literature for samples from the Chilean coast (Mytilus chilensis) may cease to be used.

Members of the family Tellinidae are considered major components of trophic chains in sheltered sandy beaches located in temperate and tropical waters, due to their high number of species and abundance, as well as their several ecological functions. The population dynamics and secondary production of two congeneric bivalves Tellina lineata and Tellina versicolor were assessed in a sheltered beach environment. Monthly samplings from December 2006 to February 2009 were carried out at Flexeiras beach in southeastern Brazil. Samplings were conducted according to a systematic design, where six transects (fixed 20 m apart) were established, each with 10 equally spaced sampling levels. From each level, a sampling unit (0.04 m²) was taken. The populations differed in several aspects as follows: (1) T. lineata showed a significant preference for occupying the intermediate levels of the beach, whereas T. versicolor showed higher densities at lower levels, (2) T. lineata had significantly higher density, grew significantly slower, the mortality rate was lower and the biomass (B), secondary production (P) and turnover rates (P/B) were higher than for T. versicolor. The differences in population parameters of the two species may be associated a difference in the species' capacities to use resources available in the marine environment.

The Mussel Watch Program sampled bays on the East, Gulf, and West coasts of the United States over a period of 16 y. Analytical protocols included the recording of parasites and pathologies. Oysters (Crassostrea virginica) harbored significantly more parasitic taxa than mussels (Mytilidae). Cases where body burden was higher in mytilids were exclusively eukaryotic parasites, trematode metacercariae and trematode sporocysts. Oysters had higher body burdens of Nematopsis, alimentary tract ciliates, prokaryotic inclusions, and a number of unique taxa including haplosporidians, Perkinsus marinus, cestodes, and nematodes. Major pathologies were much more common in mytilids. For oysters, many parasitic taxa were more common in the Gulf of Mexico, including Nematopsis, P. marinus, trematode sporocysts, and nematodes. For mytilids, most parasites and pathologies were more common on the East Coast. Most parasite distributions were clinal on the East and West coasts, with clear relationships to well-known provincial boundaries. West Coast mytilids and East Coast oysters showed a similar trend toward increased parasite weighted prevalence in the south. The greater body burdens in Gulf Coast oysters might be a continuation of this trend. East Coast mytilids offer an opposing trend with higher body burdens in the Gulf of Maine. An increasing incidence of pathologies in mytilids at northern latitudes on both coasts runs contrary to the antithetical trends on the two coasts for parasite weighted prevalences. Within the parasite-rich Gulf of Mexico, oysters from the Texas coast were notable for their higher parasite body burdens. Some parasites and pathologies tended to have low variance-to-mean ratios and thus be identified as having even distributional patterns. Others showed a large range of weighted prevalences within a region and thus had contagious distributional patterns. With the exception of P. marinus, most of the contagious parasites were single celled. The multicellular taxa were more uniformly distributed: they tended to have much lower variance-to-mean ratios. Likely, the difference in spatial distribution between single-celled and multicellular taxa is due to the tendency for single-celled organisms to proliferate within the host or, being small, the ability to accumulate in larger numbers within the host.

Parasites and pathologies of oysters and mussels were sampled yearly from 1995 to 2010 from the Gulf of Maine to Alaska and the Great Lakes as part of the National Oceanic and Atmospheric Administration Status and Trends Mussel Watch Program. Sentinel bivalves included mytilid mussels, dreissenid mussels, and oysters. This comprehensive dataset provides a unique opportunity to examine long-term temporal dynamics of parasites, pathologies, and physiological indices of these sentinel bivalves. Temporal dynamics fell into a few clear categories. Significant differences between years occurred commonly for parasites, pathologies, and physiological indices; the absence of significant change over time was more noteworthy. In a few cases, these trends were characterized by multiyear increases or decreases in value within the time series. Such behavior might be produced by a multiyear cycle and, in fact, such behavior was much more common along the southern East Coast, the Gulf Coast, and Southern California where a relatively short cycle, El Niño-Southern Oscillation (ENSO), is well documented. More interestingly, for a number of parasites, pathologies, and physiological indices, significant trends existed across the time series. These trends substantively exceed the time span of climate cycles influencing these regions such as ENSO and the North Atlantic Oscillation. A few of these longer term coherent trends were continental in scale, being observed across sentinel taxa and multiple coasts. Continental scale trends were restricted to the physiological indices such as length. Regional trends were important for a subset of parasites, pathologies, and physiological indices. In general, the regional trends were produced by single-celled proliferating parasites such as Perkinsus marinus, the major pathologies, and certain physiological indices. The multicellular eukaryotes and the gregarines often showed significant year-to-year changes without trend. Temporal trends were prominently represented by oyster parasites on the Atlantic and Gulf Coasts and by mytilid parasites on the West Coast. Pathologies by contrast had strong temporal signals in northeastern mytilids.

Multinucleate Sphere X (MSX) is an important pathogen of the eastern oyster (Crassostrea virginica) on the east coast of North America. This parasite is currently not present in Prince Edward Island (PEI), but there are concerns that it will spread from Cape Breton, Nova Scotia, where it was recently identified. Introduction of MSX to PEI would cause direct losses to the shellfish industry and it would have long-term implications for exports of oysters. The main goal of this study was to assess the risk of introduction and dissemination of MSX, as estimated by the number of movements of commercial oysters from three data sources. The in-degree (incoming) and out-degree (outgoing) of the contact network among bays, estuaries, and rivers were used to quantify the risks. For a single location on PEI, identification of up to 55 incoming and up to 26 outgoing movements to and from different locations within PEI were recorded. This suggests that if MSX was introduced it could be disseminated quickly. Movements of shellfish (oysters and mussels) from New Brunswick and Nova Scotia, which pose additional risks of pathogen introduction to PEI, were also identified. Two locations (New London Bay and the East-North-West River complex) were consistently ranked in the top quartile of incoming movements by the three data sources. In addition, two other locations (Bideford Area and Conway Narrows) were classified in the same quartile by only two of the data sources, suggesting that these four areas can be considered at high risk for pathogen introduction. Similarly, two locations were classified in the top quartile of outgoing movements (East-North-West River complex and Orwell Area) by the three data sources, whereas Bideford Area and Foxley River were only identified by two of the three data sources in the same quartile. These results indicate not only risk areas for pathogen introduction or dissemination, but also those areas having both high risk of introduction and high risk of dissemination (e.g., East-North-West River complex). Results of this study illustrate the potential consequences of MSX should Haplosporidium nelsoni reach PEI. Findings also highlight the need for the development of a system that captures all shellfish movements, which will be essential to mounting an effective response to pathogen introduction and mitigation of disease dissemination.

Methods to increase the precision of spat collection and strategies to mitigate fouling are greatly needed in aquaculture production. As such, larval recruitment of mussels and a common tunicate species was investigated. Recruitment was measured in shallow (1–2 m) and deeper (4–5 m) water at three sites during the summer of 2012. In addition, to evaluate the importance of timing in deployment of mussel ropes, differences in mussel yield were examined. The settlement plates provided a good description of the settling community with high temporal resolution. Peaks in recruitment were observed for both mussels and tunicates but recruitment rates and the timing of peaks differed among sites. Although mussel larvae preferred shaded substrates at some sites and times, these substrates were consistently preferred by tunicates. Mussels preferred to settle at shallow depths, whereas tunicates were consistently more abundant deeper. In contrast to predictions, there was no positive relationship between the yield of mussels on ropes and settlement rates on corresponding weeks. Somewhat surprisingly, the final abundance of mussels and tunicates were not related to the length of the recruitment and growth period. These results indicate that not only initial recruitment, but also mortality and repeated recruitment events are important processes shaping these dynamic assemblages. Combining the results, a minimum recommendation for monitoring larval settlement is to use, at two depths, one monitoring unit with several dark-surfaced sampling plates. Considering the fact that timing of deployment of mussel ropes in relation to mussel and tunicate settlement has been identified as a problem, it is believed that such methods can be used to optimize production of mussels. Thus, studies like these can also contribute to optimize farming techniques and practices in a broader context.

Two laboratory studies were conducted to determine the effects of coal particles in aquatic sediments on survival and organ tissues of rainbow mussels Villosa iris (Lea, 1929). First, mussel survival was assessed using treatments comprised of sand substrates with different percentages of pulverized coal, including 0%, 10%, 25%, and 50%. At the end of this 7-wk pilot experiment, there were no significant differences in survival of V. iris among substrate treatments. Second, effects of coal particles in substrate on organ tissues of V. iris, including gills, digestive glands, kidneys, and gonads, were assessed during a 20-wk experiment. Two sand substrates, containing 0% coal (control) and 50% coal (treatment), were tested. Organ tissues of five mussels from each of the treatment and control tanks were collected at 8, 16, and 20 wk. Sublethal alterations in organ tissues of coal-exposed mussels were observed. Fractions of gill filaments without cilia and digestive cells of digestive glands with condensed cytoplasm were significantly greater in coal-exposed mussels compared with those from the control. Females from the coal treatment showed significantly higher fractions of acini containing atretic, resorbing oocytes than the control females. Significantly higher fractions of lipofuscin, an insoluble lipid peroxidation byproduct that can be related to contaminant exposure, in kidney diverticula of the coal-exposed mussels suggested that unidentified contaminants were present in the water. Further study of the effects of these contaminants on freshwater mussels are warranted given the co-occurrence of declining mussel populations and coal mining and processing operations in Appalachian watersheds.

Chemical treatment for the control of the spread of zebra mussels in watercraft is typically focused on the early life stages of the mussel. Adult mussels may be spread via attachment or entangling to gear that is brought on board. Sodium chloride is a chemical that has been recommended for use during some aquacultural practices as a mussel disinfectant. The effectiveness of three sodium chloride-based salts (high-grade sodium chloride, iodized table salt, and water softener salt) was examined for their use as an adult zebra mussel decontamination solution. High-grade sodium chloride and iodized table salt both caused complete mortality at 30.000 mg/l in 24 h. Water softener salt caused complete mortality at the same concentration at 48 h. Iodized table salt caused complete mortality at a lower concentration faster than the laboratory-grade sodium chloride. On the basis of the results of this study, iodized table salt may be an acceptable alternative to high-grade sodium chloride for decontamination of zebra mussels, costing much less and leading to an increase in spread-prevention effectiveness.

To understand the underlying mechanism of the Pacific white shrimp Litopenaeus vannamei responding to acute salinity stress. RNA-seq was used to determine the transcriptome response of shrimp muscle and gill after ambient salinity changed from salinity of 20 (control) to 3 in 24 h. A total of 281.4 million reads were obtained and assembled into 105.153 contigs with an average length of 984 bp. Comparison of gene expression between shrimp exposed to salinity of 3 and the salinity control revealed that 991 and 3.709 genes were differently expressed in the gill and muscle, respectively. Both in muscle and gill, the changes of pathway can be categorized into oxidative pathways, signal transduction pathways, and metabolism pathways. More pathways significantly responded in gill than in muscle in metabolism and signal transduction. The significant change of pathways revealed that under acute low salinity stress, the increase of energy derived from carbohydrate, amino acid, or lipid in gill could satisfy the extra energy requirement of shrimp under salinity stress, but also lead to an overproduction of reactive oxygen species. For the maintenance of homeostasis, protein ubiquitination and relevant pathways were activated to remove the excessive reactive oxygen species and metabolite waste.

The Caribbean king crab Damithrax spinosissimus, a phyletie giant and the largest crab in the western Atlantic, was used to explore the costs of brooding, in terms of reproductive investment, in marine invertebrates. Given (i) the theoretical allometry between gamete production and brooding surfaces and (ii) increased physiological costs with increased brood mass, it was expected that larger broods from larger crabs should suffer higher mortality and brood loss than smaller broods from smaller crabs. It was also expected that smaller females should allocate disproportionably more resources to egg production than larger females. In D. spinosissimus, fecundity in females carrying early and late embryos varied, respectively, between 5.170 and 26.024 eggs/crab (mean ± SD = 16.569 ± 4.899) and between 1.966 and 26.906 eggs/crab (15.147 ± 7.003). In disagreement with expectation, females did not experience brood loss during embryo development. Egg mortality in females carrying early and late eggs varied, respectively, between 0% and 69% (4.71 ± 15.37) and between 2% and 100% (27.17 ± 33.99). Also in disagreement with expectations, egg mortality did not increase disproportionably with parental female body size. Reproductive output varied between 10.45% and 43.79% (34.02% ± 7.4) of crab body dry weight. Finally, in agreement with expectations, the slope (b = 0.54 ± 0.17) of the line describing the relationship between brood and parental female dry weight was significantly less than unity. Overall, most of the results disagree with the notion that the allometry of gamete production and increased physiological costs with increased brood size explain the association between brooding and small body size in marine invertebrates. Comparative studies on the reproductive investment of brooding species pertaining to monophyletic clades with extensive disparity in body size are warranted to further our understanding about the evolution of brooding in marine invertebrates.

The swimming crab Portunus trituberculatus is an important fishery and aquaculture species in China, and salinity has a significant effect on its physiological processes. To verify whether the calcyclin-binding protein (CacyBP) gene is related to salinity stress adaptation, a cDNA fragment of P. trituberculatus CacyBP was amplified and cloned. The cloned PtCacyBP fragment contains 702 nucleotides encoding 233 amino acids, with a calculated molecular weight of 26.35 kDa. PtCacyBP has approximately 40% amino acid sequence identity with homologs from other known species. To further validate the salinity tolerance roles of PtCacyBP. this study investigated the prokaryotic and eukaryotic expression of a PtCacyBP recombinant plasmid under a series of salinity stresses. A recombinant pET28( )-PtCacyBP prokaryotic expression plasmid was constructed and expressed in Escherichia coli DE3 (BL21). Moreover, an EGFP-C2-PtCacyBP eukaryotic expression plasmid was constructed and transfected into 293T cells, which were grown under a series of salinity stresses. During these salinity challenges, the survival of both prokaryotic and eukaryotic cells with the recombinant plasmid was significantly higher than the survival of cells that contained the plasmid without an insert. Therefore, the results indicate that PtCacyBP confers a protective effect against salinity stress and may be involved in the physiological process of salinity adaptation in P. trituberculatus.

Identifying suitable alternatives to fish oil for inclusion in formulated diets for aquaculture species is becoming increasingly important; however, relatively few studies have assessed the potential of terrestrial oils as possible replacements for fish oil in diets for marine crustaceans. This study examined the potential of soybean oil as a partial or complete replacement for fish oil in diets for blue swimmer crab Portunus pelagicus juveniles. Seven iso-nitrogenous and iso-lipidic diets were formulated to contain soybean oil to fish oil ratios of 1:0. 3:1. 2:1. 1:1. 1:2. 1:3. and 0:1. They were fed to first-stage crabs over four molts and survival, development, and growth of the crabs were measured. Crabs fed the diet containing soybean oil as the sole lipid source (i.e., soybean oil:fish oil ratio 1:0 treatment) recorded the lowest survival among treatments, significantly longer intermolt duration, and significantly lower specific growth rates compared with other treatments. Improved performance was shown by crabs fed diets containing fish oil at the same, or higher, dietary level than soybean oil but the best survival, shortest intermolt duration, and fastest growth rates were recorded for crabs fed the diet containing the soybean oil:fish oil ratio of 1:1. The results indicated that P. pelagicus juveniles require a balance of dietary n-3 and n-6 fatty acids and thus dietary lipid requirements can be met partially by soybean oil. Diets containing soybean oil are cheaper to produce than traditional fish oil—based diets and soybean oil is a more sustainably sourced ingredient than fish oil. Our results should support further development of the P. pelagicus aquaculture industry.

The effect of temperature and salinity on the larval development of the common spider crab Maja brachydactyla (Balss, 1922) were studied in the laboratory. Larvae were reared at different salinities (0–45) at constant temperature, and under six different combinations of temperature (18 and 21°C) and salinity (30, 35, and 40). The survival and developmental time from newly hatched zoeae to the megalopa stage and from megalopa to the first juvenile stage was quantified; the 24 h median lethal salinity (LS₅₀) for first zoeal stage was calculated. Dry mass (DM), elemental body composition (Carbon, Hydrogen, Nitrogen) and carbon: nitrogen ratio (C:N) were determined in both starved and nourished zoeae. The lower and upper LS₅₀ for M. brachydactyla first zoea in 24 h were 19.9 and 56.0, respectively; similar to other marine stenohaline brachyuran larvae. The megalopa stage was reached in a salinity range from 30 to 40. The highest survival rates to the first juvenile stage were observed at salinity: 35 and temperature: 21°C. Salinity was the key parameter for the survival to first juvenile, whereas the temperature had a higher effect over the duration of the larval development. The greatest loss of DM in starving and nourished zoeae was observed at low salinity (25). No differences were found in DM or C:N during the megalopa stage. The culture and ecological implications of the salinity tolerance of M. brachydactyla larvae are discussed.

This study identified and quantified in the field the natural predators of juvenile spiny lobster Jasus frontalis, an endemic, ecologically relevant species, and the most valuable local commercial catch of Robinson Crusoe Island. It also assessed the predation pressure that these predators exerted on juveniles lobsters and whether they showed preferences for particular body sizes within the juvenile size range. A series of tethering experiments were performed in three coastal sites of Robinson Crusoe Island (Juan Fernández archipelago. Chile). In overnight experiments, survival of juveniles decreased over time in all three sites, reaching ∼50% at the end of the experiment. The evidence suggests that fish were relevant predators since mortality of lobsters was proportional to their abundance. Although video surveillances depicted numerous octopus attacks, their abundance did not exhibit a statistically significant relationship with lobster mortality. Predatory events were not selective of juvenile sizes. These results are fundamental to understand one of the key factor (i.e., predation) that affects the juvenile (and more vulnerable) benthic phase of J. frontalis.

The American lobster Homarus americanas shares rocky shore habitats and resources with two common invasive crab species in the northwest Atlantic: the green crab Carcinus maenas and the Asian shore crab Hemigrapsus sanguineus. Juvenile or early benthic phase (EBP) lobsters live under the same boulders as these crabs and are potentially vulnerable to crab predation and competition. Time-lapse photography was used to quantify aggressive interactions between EBP lobsters and invasive crabs in the laboratory. Lobsters behaved far more aggressively toward Asian shore crabs (initiating 11.8 attacks/h) than green crabs (4.9 attacks/h). Crab behavior varied widely as well, as green crabs were five times more likely to attack EBP lobsters than were Asian shore crabs. Thus, lobsters initiated 75.5% of aggressive interactions with Asian shore crabs, compared with only 22.3% with green crabs. Invasion history was a possible reason for this disparity, as green crabs have shared geographic range with American lobsters for more than 100 y. compared with only more than 10 y for Asian shore crabs. Differences in lobster responses to the two crab species suggest that aggressive behavior is the default for EBP lobsters and that they attacked the novel species (H. sanguineus) because they had not developed avoidance behavior to the potential crab threat. Green crabs posed more of a predation threat than Asian shore crabs, consuming over 80% of lobsters in 24-h trials. These results suggest that invasion history and predator—prey adaptation may shape the behavior and ecological interactions of native and invasive species.

The timing and spatial variation in spawning in the green sea urchin Strongylocentrotus droebachiensis (Müller) was investigated at three moderately protected sites in each of three geographic regions along the coast of Maine before the commencement of significant commercial harvesting. Urchins were sampled monthly (1987 to 1988) from subtidal hard bottoms, and test diameter (TD), height, total wet weight, and gonad wet weight were measured. To interpret reproductive and spawning patterns additional data were taken on habitat type, water temperature, salinity, urchin density, and diets. Over a range of TD (34.1–89.4 mm), 1,594 urchins were sampled. Gonad index (GI) increased as an allometric function of TD, and for urchins from the northeast and southwest regions, GI was independent of TD for animals ≥64 mm. In the central region, the size at independencewas ≥55 mm. Analysis of variance with a priori, planned contrasts was used to quantify temporal changes in GI and spawning at two spatial scales (within and between regions). This information serves as a preharvest baseline for green urchin dynamics, analysis of reproductive cycles and spawning, and for current and future ocean changes. Gonad index and spawning varied seasonally, spatially and interannually. Gonad index increased during fall and early winter, and peaked in midwinter before a major spawning event in April at seven of nine sites. Gonad index ranged from 10%to 20% from December to April. Spawning [measured as a steep decline in GI (48%–78%) between successive sampling dates) occurred between early April and mid-May, except at one site in the central (Lamoine: March to April) and one in the northeast (Jonesport: May to June) regions. Gonad index patterns during spawning corresponded inversely to increasing seawater temperatures in the range of 2.5–5 °C. Salinity, urchin density, and test size did not explain a significant proportion of the variability in mean GI through time. Diets consisted primarily of diatoms and microalgae on ledge, sediment, and coralline barrens and showed no regional trends. Sex ratio explained a significant portion of the variability in mean GI at only one site. Seawater temperature, however, explained 55%–77% of the variability in mean GI through time. Predicting when spawning occurs in natural populations is central to the sea urchin fishery by refining estimates of what are termed harvest windows (HW). The HW represents a segment of time during the general spawning season when GI are at, or above, a specified percent, for example, 10%. A review of the literature uncovered 19 different techniques to determine GI and assess spawning. Of 167 papers published between 1922 and 2013 in which methods of spawning in wild populations of sea urchins were described, 84 and 134 used histology and GI, respectively. This study contributes to the questions of dependence of GI on test size, first illuminated by Gonor (1972), and the general practice of interpreting minor declines in GI as fractional spawning events, rather than simply sampling noise. The use of statistical tests is encouraged to define aspects of the reproductive cycle in sea urchins.

For over 30 y, a mouse bioassay has been used to monitor paralytic shellfish poisoning (PSP) toxicity in shellfish harvested along the coast of Uruguay. Although providing a good controlmechanism for the safety of shellfish consumers, the assay is known to have several disadvantages. To assess the potential for use of liquid chromatography with fluorescence detection, a study was conducted to analyze shellfish samples harvested over a 20-y period using this alternative method. Mussels and clams were analyzed using the AOAC Official Method 2005.06 with results compared with those obtained from the original mouse bioassay and used to determine the presence of specific toxin congeners. The chromatographic results from nontoxic samples indicated no specificity issues resulting fromthe potential presence of naturally fluorescent coextractives but with complex and variable toxin distributions in samples designated PSP-positive by the bioassay. Although some species-related differences in toxin profile may be attributed to differences in shellfish metabolism, clear profiles were noted in shellfish harvested during two distinct phytoplankton blooms of Gymnodinium catenatumand Alexandriumtamarense. The work therefore showed evidence for the presence of awide range of toxin congeners and the need for any replacement quantitative method to be fully capable of analyzing the major toxins of importance. Some differences between the toxicity results determined by the twomethods indicated, however, the need for further investigations to assess the potential presence of other toxins, which may remain undetected using AOAC 2005.06.

The marine dinoflagellate genus Dinophysis Ehrenberg is globally distributed in coastal and oceanic waters and can produce lipophilic toxins. These toxins can accumulate in filter-feeding shellfish and cause diarrhetic shellfish poisoning (DSP). Between 2009 and 2011 the two most frequent and abundant Dinophysis species found in North Patagonian gulfs were Dinophysis tripos Gourret and Dinophysis acuminata Claparéde and Lachmann, and in 2015 D. tripos was the only toxic species found in moderate to high relative abundances when mouse bioassay results for DSP were positive. The positive results from mouse bioassay for DSP agree with moderate to high relative abundances of D. tripos and it was the only potentially toxic Dinophysis species found in the samples. The toxin profiles consisted mainly of pectentoxin-2 (PTX-2) followed by PTX-11 and PTX-2 seco acid. The toxin profiles of the samples could be associated with D. tripos, because the maximum proportion of D. acuminata did not exceed 1.3% of total Dinophysis cells in any of the samples. The results suggest that shellfish accumulated high levels of PTX when D. tripos was at a high abundance. To our knowledge, this is the first record of positive results in the mouse bioassay for DSP related to D. tripos and with closures of shellfish harvesting in North Patagonian gulfs.

Mariculture and recreational zones are expanding rapidly along the coast of Primorsky Krai in the Russian Far East, increasing the pressing need for monitoring of toxin-producing algae and seafood poisoning. One poisoning syndrome, diarrhetic shellfish poisoning has not been reported in this region, but its expansion to other subarctic waters has been observed. To our knowledge, the research here shows the first measures of diarrhetic shellfish toxins (DST) on the east coast of Russia. Mussels contained DST concentrations above the recommended regulatory level of 16 mg/100 g shellfish at almost all sites sampled in the Primorsky Krai region, with maximum concentrations of 56.3 mg/100 g. The primary DST isoform was dinophysistoxin-1 (DTX-1; 94%-100%) but minor amounts of okadaic acid (0%-6%) also were detected. Other lipophilic toxins measured in shellfish were yessotoxin , pectenotoxin-2 (PTX-2), and azaspiracid-2; the last two toxins observed in Russian water for the first time. Phytoplankton samples dominated by Dinophysis acuminata contained DST, indicating that it was likely responsible for shellfish toxicity. Particulate seawater samples with Dinophysis contained 2.1–10.2 ng DTX-1/l and 6.5–101.8 ng PTX-2/l, corresponding to cellular concentrations of 3.1–5.6 pg DTX-1/cell and 9.6–46.7 pg PTX-2/cell. These findings provide a foundation for a Federal Monitoring Program for harmful algal blooms and phycotoxin control in seafood in Russia, and suggest that appropriate methods for both rapid screening and regulation of shellfish toxins should be established to ensure safe harvest in Russia.

Human-induced climate change and ocean acidification are global environmental phenomena with a common driver: anthropogenic emissions of carbon dioxide. Both processes potentially threaten the Mediterranean bivalve mollusc aquaculture sector, which is economically relevant to several regions and countries. Detrimental effects on bivalve mollusc species might arise from the associated increase in sea surface temperature, pH reduction, higher frequency of extreme climatic events, and possible synergies with other nonclimatic stressors, such as harmful algal blooms and mollusc diseases. This paper presents the results of a questionnaire-based study of Mediterranean bivalve mollusc producers from 12 coastal regions and six countries, the latter including those with the highest production share in the Mediterranean region. This study aims to assess knowledge and perception of threat of climatic and nonclimatic environmental stressors within the Mediterranean aquaculture industry. Furthermore, it collects information about the (geographical) impacts of summer heat waves and ocean acidification. The results suggest that ocean acidification is still a relatively unknown phenomenon and generally poorly understood.Moreover, it is considered a secondary threat compared with other pressures. Summer heat waves are presently perceived as the highest threat, having been observed in amajority of the studied production sites in past years,with effects on seed (spat), adultmortality, and byssus attachment.