Illegal harvesting of oysters is a concern for a broad range of stakeholders in the Chesapeake Bay region, including natural resource managers, oyster growers, fishermen, environmentalists, and public health advocates. This study analyzed oyster harvest citations issued by marine police in Maryland (n = 5,282 citations) from 1959 to 2010 as well as judicial decisions and fines resulting from these citations. Nearly three quarters of citations (73.9%) were issued for harvesting undersized or unculled oysters, or exceeding the daily catch limit. The citation rate per year was inversely proportional to the number of person-days worked. Of those individuals with a citation, 45% received citations on multiple days; ca. 10% of individuals had 5 days or more with at least 1 citation. Citations and harvests after 1994 were mapped using GIS. Eighty-two percent of court cases for oyster citations resulted in guilty verdicts. The distribution of court cases by county and verdict are presented. During the past decade (2000 to 2009), Maryland courts issued fines totaling $150,237 (mean fine, $179). Implications of our findings for oyster ecology and natural resource management in the Maryland portion of the Chesapeake Bay are discussed.

Oysters and the reefs they build are being recognized and restored increasingly for the broad suite of ecosystem services they can provide. However, surprisingly little effort has been devoted to documenting the outcomes of such restoration or creation projects through time, or to comparing projects from different regions. In this study, we examined the oyster (Crassostrea ariakensis) and benthic macrofaunal development on a created intertidal oyster (Crassostrea ariakensis) reef along a salinity and exposure (vertical position on reef) gradient 5 y after creation in the Yangtze River estuary, China. Three years after reef creation, sustainable oyster populations were established successfully and market-size oysters accounted for more than 24% of the total reef cover, with mean abundances ranging from 95–225 adult oysters/m². Associated community metrics (species richness, abundance. and biomass) of benthic macrofauna showed generally increasing trends with reef development during the 5-y period; however, crustaceans and polychaetes were correlated most strongly with oyster development. Barnacle (Balanus alhicostatus) abundance and biomass were correlated negatively with oyster and reef development. Salinity and exposure frequently interacted, suggesting that development at different places along the reef or salinity gradient was dependent on the vertical position along the reef or the degree of exposure at low tide. Oyster development on this created reef appears to be at a self-sustaining level and provides habitat for associated benthic macrofauna comparable with other regions globally.

Ten polymorphic microsatellite loci were multiplexed to analyze a total of 343 Pacific oysters (Crassostrea gigas) sampled from native (Japan and Korea), naturalized (France and Australia), and cultured (3 Australian programs) populations. Genetic diversity was high within the native and naturalized populations (average allelic richness, 18.7; expected heterozygosity, 0.89), but lower within samples from hatchery populations (allelic richness, 12.3; expected heterozygosity, 0.84). A significant decrease in diversity was found within Australian cultured populations. However, diversity was shown to be similar in samples from a well-managed, family-based selective breeding population and commercial hatchery mass spawning populations. The Bayesian analysis of population structure found no difference between native and naturalized samples, which, together with other results, indicate that the naturalized populations have not changed genetically since their introduction. This suggests that naturalized populations can provide a good source of genetic diversity for breeding programs.

Interspecific hybridization is a useful tool in genetic improvement of agriculture and aquaculture species. The Pacific oyster (Crassostrea gigas) and the Hong Kong oyster (Crassostrea hongkongensis) are both important aquaculture species in China. To determine whether these 2 species can hybridize and produce viable offspring, we conducted 2×2 factorial crosses between them. Asymmetry in fertilization was observed when C. hongkongensis eggs were fertilized readily by C. gigas sperm, but the reciprocal cross resulted in no fertilization. Embryos from C. hongkongensis female × C. gigas male crosses developed normally without noticeable defects, although their survival rate to D-stage was less than embryos of the two intraspecific crosses. From D-stage to metamorphosis, larvae of hybrid crosses had slower growth and a lower survival rate than that of intraspecific crosses. Nevertheless, 0.57% of hybrid D-larvae survived to spat stage at day 90. Hybrid spat had good survival (78.9%) to 1 y of age, but were significantly (P < 0.001) smaller than oysters of intraspecific crosses. Gonadal development was absent or retarded in most hybrids at 1 y of age, although some hybrids (39.2%) produced mature gametes. Our results show that hybridization between C. gigas and C. hongkongensis is possible in one direction. Some hybrids are viable, partly fertile, and can be used potentially for gene introgression between these two species.

The Pacific oyster, Crassostrea gigas, is an intertidal bivalve mollusc that inhabits several continents. Similar to other shellfish, the Pacific oyster is considered an important bioindicator species. One way to assess environmental perturbations is to examine an organism's stress response. Molecular chaperones, including heat shock proteins, are common targets when evaluating an organism's response to environmental stress. In this study, oysters were exposed to copper and the bacterium Vibrio tubiashii to characterize how these environmental stressors influence Hsp70 gene and protein expression. Bacterial exposure did not affect Hsp70 expression, whereas copper exposure changed both transcript and protein levels significantly. Interestingly, copper exposure increased gene expression and decreased protein levels when compared with controls. The dynamics of Hsp70 regulation observed here provide important insight into heavy metal exposure and heat shock protein levels in oysters, highlighting considerations that should be made when using Hsp70 as an indicator of an organism's general stress response.

The Eastern oyster Crassostrea virginica is a marine bivalve that has been used extensively in metal bioaccumulation studies. We exposed C. virginica to 0 mg/L cadmium, 0.1 mg/L cadmium, or 0.5 mg/L cadmium in seawater for 96 h and then measure the activity of enzymes (amylase, laminarinase, and protease) in the digestive gland. The levels of cadmium in the gills and digestive glands of the animals were also determined. Exposure of the animals to 0.5 mg/L cadmium resulted in a significant decrease in the activities of amylase, laminarinase, and protease enzymes compared with oysters exposed to either 0 mg/L cadmium or 0.1 mg/L cadmium. This decrease corresponds to significantly higher cadmium levels in the gills and digestive glands of oysters exposed to 0.5 mg/L cadmium. The results of this study suggest that exposure to cadmium affects the ability of the animals to process ingested food.

Ten-year time series (1992 to 2002) of salinity, Dermo disease, and size-class structure and mortality measured for an eastern oyster (Crassostrea virginica) population at a reef in Bay Tambour, Terrebonne Parish, LA, were analyzed using wavelet techniques to determine dominant frequencies and correlations. Along the Gulf Coast of the United States, Dermo disease (caused by Perkinsus marinus) responds to the El Niño-Southern Oscillation (ENSO) climate signal through its response to salinity. During the La Niña portion of ENSO, decreased rainfall leads to an increase in salinity, which triggers a rise in Dermo disease prevalence and intensity, producing increased oyster mortality. Although disease responds to the 4-y periodicity of ENSO and salinity, the oyster population dynamics do not appear to be controlled by disease at this site. A significant 4-y coherency exists between recruitment and salinity, with recruitment being higher during periods of high salinity. Recruit numbers and submarket numbers also exhibit a strong 4-y periodicity. However, a relationship between the recruit time series and the subsequent change in market-size abundance did not exist. The complexity of postsettlement processes and the extended time over which these processes interact decrease the predictability of the recruit-to-market transition. Even the strong pulse of recruits associated with La Niña and its locally elevated salinities did not result in an exceptional abundance of market oysters. Understanding the environmental and biotic factors that favor the production of large oysters is critical because large oysters not only supply the fishery, but, upon their death, contribute the bulk of the shell required for reef sustainability.

The ratio of ¹⁸O to ¹⁶O in the shell material of bivalves depends on the ambient water temperature at the time the shell material was deposited. By analyzing samples of shell material taken sequentially from the umbo to the shell margin, we obtained the oxygen isotopic records from the shells of 14 sea scallops (Placopecten magellanicus) and compared the isotope data with the visible rings on the upper valve. Using generalized additive models, we show that ring formation is related significantly to water temperature, and that rings were typically laid down near the annual temperature maximum. Shell ring formation was generally annual, although 2 of the mid-Atlantic scallops appeared to have laid down 2 rings in 1 y. Some of the scallops appear to form new shell material and increase in shell height over the entire year for the first few years of life, and in later years reduce or halt accretion at the shell margin during the coldest temperatures. The isotopic records obtained from near the umbo of the shells suggest that all but one of the scallops were spawned in the fall.

It is well known that immune defenses of bivalves against environmental and pathogenic stresses are primarily attributable to hemocytes. Hemocyte parameters are being used progressively as indicators to assess the host immune status. Moreover, there is increasing evidence that seasonal variations on the immune status have two origins: exogenous and endogenous. In this work, we investigated the effects of seasonal exogenous (water temperature and food availability) and endogenous (size and reproduction) factors on the hemocyte parameters in the scallop Chlamys farreri. Scallops were monthly collected from February to December 2009 at 2 sampling sites differing in culture mode: Qingdao for monoculture and Weihai for scallop—kelp polyculture. Six hemocyte parameters including total hemocyte count (THC), granulocyte percentage (GP), intrahemocytic phenoloxidase (PO), acid phosphatase (ACP), superoxide dismutase (SOD), and peroxidase (POD) were analyzed. Results illustrated that all hemocyte parameters exhibited marked seasonal variations, following a similar pattern at both sites. High values of THC, GP, PO, and POD were observed in spring and early summer, a period of favorable water temperature and high food availability and gonad index, whereas low values were found in summer and early autumn, a period corresponding to reproduction completion and high water temperature. Moreover, SOD was lowest in February and highest in August, and correlated positively with water temperature. Hemocyte parameters in the scallop C. farreri varied greatly among seasons, and their values were generally low during summer and early autumn, suggesting that scallops had a depressed immune status during this period.

Elemental fingerprinting of adult and juvenile Nantucket bay scallop shells, Argopecten irradians (Lamarck 1819) revealed distinct element/Ca ratios that can be used to distinguish provenance of bay scallops in Nantucket Harbor. Within this small harbor (∼ 10 km²), we identified 3 distinct habitat zones defined by the abundance of scallops at a location: zone 1 (barren), zone 2 (low abundance), and zone 3 (high abundance). Element/Ca ratios were associated with proximity to the harbor mouth, with elemental differences attributed to variation in salinity and pH. Using binary logistic regression, we identified the source zones based on shell elemental ratios (i.e., various elemental concentrations divided by [Ca]). We also identified boundary salinity and pH conditions that support large abundance of A. irradians within Nantucket Harbor. This information is crucial to seeding projects and the management of the Nantucket Harbor A. irradians population.

Spat of 2 pectinid species of commercial interest were grown in suspension to study the growth of the gonad, digestive gland, and adductor muscle at 3 different depths (2.5 m, 7.5 m, and 12.5 m). For the experiments, we used spat immediately after they were detached from the collectors (Aequipecten opercularis) or 3–4 mo later (Chlamys varia). The first sexual maturation of each species was recorded. The variations observed in the gonad development pattern were clearly a result of the effect of depth on the gonad growth of the 2 species. Both species showed faster gonad development at 2.5 m. Reproduction of C. varia was more intense in deeper water. This was also the case for A. opercularis in the first reproduction period, from the end of winter to early summer. After a resting period in summer, there was a first peak of gonad growth at 2.5 m in October that did not occur at 7.5 m and 12.5 m. There was a peak in January at all depths. The reserve storage organs of both A. opercularis and C. varia showed a regular pattern of evolution. In general, the variations in the reserve organs followed the same pattern at all depths with 2 exceptions: the digestive gland in C. varia in spring at 2.5 m, which showed a faster growth rate related to higher temperatures; and the digestive gland and muscle in A. opercularis, which showed a large growth peak in late spring and early summer at 12.5 m that did not occur at other depths and that was related to lower temperatures and greater food availability. The growth of the reserve organs was more conservative despite the variations in the environmental conditions that occurred during the experimental period. Gonad growth was affected more by environmental changes, and was more versatile.

Interannual variation of Perkinsus olseni infection intensity in the adult Manila clam Ruditapes philippinarum in Gomso Bay, off the west coast of Korea, was monitored from 1999 to 2000. Infection intensity of P. olseni (i.e., total number of P. olseni cells in unit tissue weight) was determined using Ray's fluid thioglycollate medium assay and Choi's 2-M NaOH digestion. In Gomso Bay, P. olseni monthly infection prevalence ranged from 83 (April 2000)–100%. It was remarkable that of the 18 mo of sampling, the prevalence remained at 100 % in 12 sampling months. Infection intensity of P. olseni in Manila clam ranged 366,001 (July 1999)–2,235,325 cells/g wet tissue (October 1999). The infection intensity recorded in 1999 was significantly higher than the level measured in 2000, suggesting an interannual variation in the intensity (P < 0.05). A very high level of infection intensity observed during the fall (September, October, and November) coincided with a relatively low condition index and mass morality of clams in the bay. Our data suggest that the mass mortality of clams observed during late summer to mid fall in Gomso Bay could be, in part, explained by the high level of Perkinsus infection coupled with the poor physiological condition of clams during the postspawning season.

Previous studies have shown that hemic neoplasia in softshell clams is related to the level of P53 -like mRNA in hemocytes. Traditionally, the p53-like mRNA level has been quantified using quantitative real-time RT-PCR (Q RT-PCR). However, this technique requires several steps that are sources of contamination and may result in a low accuracy of the analysis. The novel aspect of this study is that the p53-like mRNA level was quantified directly from a lysate of hemocytes without any RNA extraction or reverse transcription steps. This assay is based on branched DNA (bDNA) signal amplification technology and enables quantification of p53-like mRNA levels in as few as 2,500 hemocytes, with a coefficient of variation close to 6% (range, 2–12%). A significant correlation (R²= 0.99, P ≤0.01, n= 5) was found between the p53-like mRNA quantified directly from hemocytes without RNA extraction and from 1 µg total RNA extracted from hemocytes using the classic TRIzol protocol. To compare p53-like mRNA levels in hemocytes from diseased clams collected in North River (Prince Edward Island, Canada) and from healthy clams found in Havre aux Maisons at Magdalene Island (Quebec, Canada), the quantification of relative p53-like mRNA levels was performed using our single plex assay. Data showed a significantly (P ≤0.01, n= 5) high expression of p53-like in the hemocytes of clams collected from North River. Therefore, although Q RT-PCR remains the most widely used technique for the quantification of gene expression level, we believe that single plex using bDNA technology could represent a new generation of mRNA quantification tool, enabling a more efficient mollusc health management.

A previous study revealed genetic differences among collections of the commercially exploited geoduck clam (Panopea generosa) in Puget Sound, WA, but this heterogeneity did not follow an isolation-by-distance model. In this study, we investigated whether these differences were ephemeral or stable and tested predictions of the sweepstakes recruitment hypothesis, in which individuals show a high variance in reproductive success. We genotyped 11 allozyme and 7 microsatellite loci in 2,021 geoducks from 2 sites in Puget Sound and aged individuals by counting annuli in thin-section chondrophores under light microscopy. Genotypic data were then collated by year-class to test predictions of the sweepstakes recruitment hypothesis with allele count rarefaction, year-class relatedness, and 3 estimators of efective population size (N_e) using temporal shifts in allele frequencies. Although estimates of N_e were similar among year-classes, spatial shifts in allele frequencies and year-class strengths were detected among stations at 1 site, indicating that patchy settlement may be the result of an interaction between larval behavior during dispersal and hydrology.

Realistic species-specific information about larval life history is necessary for effective management of shellfish and parameterization of larval connectivity models. The patchiness of dispersing larvae, and the resources needed for sorting and identifying them, has limited many studies of larval distribution in the field, especially for species that are less common. In particular, little is known about in situ larval distribution of Pacific geoduck clams (Panopea generosa Gould 1850), a commercially important species found in Puget Sound, WA. A novel approach—time-integrating larval tube traps paired with molecular identification and sorting (FISH-CS)—was used to determine the distribution of geoduck larvae over 4 mo at 3 stations in Quartermaster Harbor. Larvae were found consistently at the surface and thermocline rather than at the bottom. More and larger larvae were captured in the inside and middle of the harbor than the outer harbor, indicating at least some larval retention. Two pulses of larvae were captured, in March and late May to early June. Size—frequency distributions of larvae indicate that these were 2 separate cohorts of larvae, with the possibility of a pulse of larvae from elsewhere toward the end of the season. The only physical parameter associated with relative larval abundance was degree of stratification, although the association was weak. These data represent the first reported study of geoduck larval distribution in the field and the first use of the FISH-CS technique for field collections. In the future, this approach can be used to answer many relevant management questions locally and more broadly, including quantifying larval export from shellfish farms, placement of restoration sites and marine protected areas, and spread of invasive species.

We describe the growth of the Cortes geoduck Panopea globosa (Dall 1898) in the Central Gulf of California using a multimodel approach. Geoducks were collected from November 2008 to February 2010 as part of an experimental fishery off Guaymas, Sonora, Mexico. Their age was established using the acetate peel method. Individual growth was estimated by means of 4 models: von Bertalanffy, logistic, Gompertz, and Schnute. The parameters in each model and their confidence intervals (CIs) were computed using the maximum likelihood method. The best-fitting model was selected using Akaike's information criterion (AIC). According to the AIC, the logistic growth model best describes the growth of P. globosa in this region. We recomputed the CIs of the best model through bootstrapping the model 1,000 times. We found that the asymptotic length of the shell of P. globosa off Guaymas (located in the Central Gulf of California) was 122.2 mm (95% CI, 116.3–128.1) by averaging the asymptotic length estimated in the 3 candidate models (Schnute was not supported). After bootstrapping, the values for the parameters and the first-order corrected 95% CI of the logistic model were L_∞ = 122.16 (118.2–124.94), K = 0.497 (0.36–0.614), and t₀ = 2.26 (1.599–2.571). We concluded that using a multimodel approach and the AIC represent the most robust method for growth parameter estimation, at least in the studied species.

There are 2 species of geoduck fished commercially in northwest Mexico: Panopea generosa, along the Pacific coast of the Baja California peninsula, and Panopea Globosa, in the Gulf of California and in Bahía Magdalena. This study describes the status of the geoduck clam fishery in northwestern Mexico. Recent surveys suggest an ample distribution of beds along both coasts of Baja California and the coast of Sonora. Landings have increased from 49 mt in 2002 to 2,000 mt in 2011. The fishery has a current annual value of approximately US$30 million, and in Sonora, stock assessments estimate the potential yield to be around 1,800 mt. Fishers in Sonora have expressed an increasing interest to enter into the geoduck fishery, and a total of 1,173,898 pieces have been authorized for new extraction in 2012. We have conducted surveys in 24 beds from February 2009 to October 2011 to evaluate the resource. Given the long life cycles of geoduck, low recruitment and high fishing rates threaten the viability of this resource unless immediate management actions are taken.

Identification of pinnid species is based largely on morphological characteristics that are highly plastic; thus, classification of pinnids remains controversial. We identified a species of Atrina, found along the southern China coast, as Atrina chinensis Deshayes, 1841, but other authors have treated it as a synonym of Atrina pectinata Linnaeus, 1767. The objective of this study was to clarify the taxonomic status of this species by comparing both morphological and genetic data with data from other Atrina species. Of the 4 shell parameters analyzed, only 1 (size of the posterior adductor) differed significantly between A. pectinata and A. chinensis. However, these species did not form a clade on the phylogenetic trees constructed based on nuclear 28S rRNA or the mitochondrial cytochrome oxidase I (mtCOI) and 16S rRNA genes. Moreover, A. chinensis is, genetically, is a sister taxon to Atrina vexillum instead of A. pectinata. We suggest that A. chinensis is a valid taxon and not a synonym of A. pectinata.

In this study, we evaluated the growth of adults and juveniles of the endangered noble pen shell Pinna nobilis, calculated the growth rates of newly recruited juveniles, and described relative directional growth during ontogeny. We described growth using posterior adductor muscle scars (PAMS) and fit of the von Bertalanffy growth curve for adult population data at shallow depths (5–10 m) around the Mallorca and Ibiza islands, and compared the parameters with other Mediterranean populations. Populations around Mallorca could be fitted according to the von Bertalanffy function L_t = 65.31(1 - e^{-0.11(t 0.53)}), whereas for Ibiza the function was L_t = 154.55(1 - e^{-0.03(t 4.31)}). We compared first-year growth rates obtained in the laboratory and from field collections with newly settled individuals. We found that experimentally evaluated growth rates of juveniles in the laboratory of 0.18 mm/day are low compared with minimum values obtained in the field, which range, on average, from 0.28–0.32 mm/day, indicating food availability can limit growth. Furthermore we investigated relative allometric growth patterns during ontogeny using a unique data set ranging from measurements of newly recruited juveniles with shell length less than 1 cm to measurements on adult shells of 69.8 cm length. Fitting a sigmoidal function to our data and solving for the allometric exponent b, we found 3 distinct growth periods: preferential growth in the length direction up to 5.82 cm in shell length, then widening of the shell up to 14.64 cm, after which the shape of the shell becomes more elongated once again.

The reproductive cycle of the cockle Cerastoderma edule was studied by histological techniques and observation of changes in the condition index during three consecutive years in the Ría de Vigo (Northwest Iberian Peninsula). The onset of gametogenesis took place at the end of the summer (September to October), progressed throughout the winter, and the mature stage was finally reached in spring. The first spawning occurred in April and May and, after gonad restoration, another spawning episode took place in May and June. During the summer (July and August), most of the population showed signs of gonad exhaustion, although a less-intensive spawning event was observed at the end of summer and beginning of autumn. This second episode coincided with a phytoplankton bloom, which acted as a stimulus for spawning. Although a simple measure, the condition index proved to be a good indicator of the gonadal cycle, because it reflected adequately the reserve accumulation during gametogenesis, maximum maturity, and gamete emission. The useful information obtained from this study can be applied in shellfishery management.

Fifteen-day pediveliger larvae of Anadara grandis (shell length, 230 ± 20 µm (mean ± SD, n = 20) were cultivated up to the juvenile stage by testing 2 densities: 71 larvae/cm² and 283 larvae/cm² for 37 days. During this time, we registered morphological changes of the larvae from pediveliger up to the juvenile stage, as well as absolute growth, and growth and survival rates. The growth rate was 53.5 µm/day at a density of 71 larvae/cm², with a survival of 60%; at a density of 283 larvae/cm², the growth rate was 33.6 µm/day, with a survival of 40%. Subsequently, the juveniles obtained were nursed for 57 days in 2 types of experimental units: Nestier trays suspended in a pond and cylindrical upwelling containers with increasing water flow in the laboratory. In each experimental unit we cultured 66,666 juveniles with a shell length of 1.57 ± 0.05 mm (n = 20). In the Nestier trays, growth was 4–6 µm/day, with a survival of 15%. In the upwelling-type units, growth was 5–6 µm/day, with a survival of 93%. ANOVA revealed significant differences (P < 0.05) in juvenile growth between the Nestier trays and the upwelling-type containers. Low juvenile survival in Nestier trays is attributed to clogging with wind-blown slime. However, a nursery of A. grandis juveniles in ponds requires further research to show its economic feasibility.

As a consequence of the current globalization of commerce, natural environments are subject to an unprecedented dynamic transport of organisms because global conditions favor transport, settlement, and dispersal of invading species. These produce widespread impacts such as decreased agricultural and utility production, increased health risks to humans and wildlife, and a significant decrease in native biodiversity. On the assumption that it is better to prevent bioinvasions than to control them, it is of paramount importance to identify and manage the potential dispersal vectors to implement preventive strategies. In our study, we identified 4 potential vectors in southern Brazil (sand transport, attachment to hulls of sports fishing boats, water in sports fishing boats, and live fish) for 2 freshwater invasive bivalves (Corbicula fluminea and Limnoperna fortunei). For each of these potential vectors, we assess the potential for dispersal by estimating the probability of finding larvae or adults, setting groundwork for further studies on the risks of invasion to which the region is subject.

Fluorescent molecules have revolutionized the field of molecular biology and biotechnology, and could be of benefit to research conducted on economically important haliotid species (abalone) for applications such as protein analysis, cell metabolism studies, fluorescence resonance energy transfer, cell imaging, and reporter genes for gene transfer. Many marine organisms exhibit autofluorescence; therefore, this raises the question whether autofluorescence also occurs in abalone and whether it could hinder fluorescence studies. We examined ova, sperm, larvae, juveniles, and hemocyte cell cultures of the southern African abalone (Haliotis midae Linnaeus, 1758) and established that ova, larvae, and juveniles exhibited autofluorescence at most wavelengths tested, especially in the mid-wavelength range of the visible spectrum. Autofluorescence was particularly prominent at the same wavelengths as that of green fluorescent proteins. Therefore, we caution studies using fluorescent molecules with emissions in the mid-wavelength range and suggest the use of molecules with emissions at the extremes of the light spectra.

Since 1969, abalone populations have declined globally more than 50%, with many species now recognized as threatened, endangered, or species of concern. As monitoring progresses and restoration efforts evolve to include population supplementation, a reliable and robust method of tagging individual abalone is needed. Current abalone tagging methods are unsatisfactory, particularly for long-term studies as a result of tag loss, shell erosion, and encrustation. Observing tag numbers of cryptically positioned abalone can be difficult. To obviate these issues, we evaluated passive integrated transponders (PITs) as tags for pinto abalone (Haliotis kamtschatkana kamtschatkana). We applied 9-mm PITs with cyanoacrylate glue to the dorsal exterior of the shell and to the ventral anterior of the shell, and by injection into the foot muscle of small adults (trial 1), and applied PITs to the ventral anterior of the shell of juveniles (trial 2). We subsequently tracked growth, survival, and tag retention over 15 mo in trial 1 and 6 mo in trial 2 in captivity. Among small adults (trial 1), differences in relative growth rate and survival were not significant. PIT retention by adhesion to the ventral anterior and dorsal exterior was significantly greater than injection into the foot in trial 1. Between controls and tagged animals in trial 2, differences in survival were not significant. There was no significant difference in ventral anterior tag retention between trial 1 and trial 2. Gluing PITs on the ventral anterior of the shell is a promising method because abalone quickly formed nacre over the tags, incorporating them into the shell, which does not appear to affect tag detection by the PIT reader. Trials are underway to characterize PIT retention in natural habitats, to determine tag longevity, and to use PITs to track adults reintroduced to aggregations.

A stomach content analysis was undertaken to determine the changes in the natural diet of the green abalone Haliotis fulgens as they relate to the 1997 to 1998 El Niño event at 2 sites along the central coast of the Baja California Peninsula. The index of relative importance of each identified food item was calculated, and Levin's index was used to determine the breadth of the diet. A total of 20 macroalgal species, 1 seagrass species, and 4 invertebrate species were observed from March 1997 to July 1998. The main constituents of the diet of H. fulgens before the 1997 to 1998 El Niño were Macrocystis pyrifera, Phyllospadix torreyi, and Cystoseira osmundacea. During and after, the principal items were Sargassum sp., Spatoglossum howelli, Cystoseira osmundacea, Dictyota sp., Gelidium sp., and Phyllospadix torreyi. Diet breadth of abalone diet was greater during and after El Niño 1997 to 1998 than before. Our results show that green abalone diet varies with the availability of the food source; therefore, El Niño events caused a major shift in diet related to changes in the local algal flora.

An Eulerian approach was applied through a daily data set (n = 51) on mantle length frequencies of jumbo squid Dosidicus gigas derived from a small jigging fleet (5 vessels), which stayed fishing in the same area off Mulegé, central Gulf of California. Data were corrected for observation bias introduced by the fishing gear (jigs) and were used to analyze population structure and growth-related parameters by modal progression analysis. Sexual maturity stages and size structure showed a predominance of medium-size immature specimens, both male and female. Mean size of jumbo squid showed a progressive increment throughout the fishing period that could be associated with growth or migration. Our estimations of growth rates were higher (3.15–3.85 mm/day) than those calculated previously for D. gigas with other methods in the same region (Gulf of California). This apparent overestimation of growth rates could be associated with a bias introduced by migration. In fact, our study area is part of some migratory routes known for this species and could be considered a transitory feeding ground for medium-size jumbo squid. The most possible explanation for the progressive increment of size (mantle length) during the fishing period considers a dynamic interaction between growth and migration.

Nassariids have a worldwide distribution and are most often found in sheltered embayments in tropical, subtropical, and temperate zones occurring in intertidal and subtidal areas. Species of this genus are scavengers, constituting a major link in the energy flow between carrion, independent of trophic levels, and the environment. The aims of this study are to compare the distribution pattern and the population biology (growth and mortality) of males and females of Nassarius vibex. Sampling was carried out monthly, at spring low tide, from September 2007 through February 2009 at Flexeiras Beach, located in Rio de Janeiro state (22°), southeastern Brazil. Sampling was conducted according to a systematic design in which biological samples were taken along 6 transects spaced equally and perpendicular to the shoreline. On each transect, 10 equally spaced sampling units (SUs) were established: the first (SU1) at the waterline, the second last (SU9) on the drift line, and the last (SU10) 3 m above the drift line (supralittoral). Highest population abundances were observed in spring for both sexes. There were significant differences in abundance among the levels in both sexes. Females of N. vibex had lower abundance, grew faster, and had higher mortality and shorter life spans than males. Variations in the population parameters of N. vibex might be regulated by phenotypic adjustment in local conditions, food availability, and, apparently, in this case, by exposure to organotin compounds inducing to the imposex.

The reproductive biology of the Panama brief squid was evaluated using reproductive indicators, and histological and histochemical analyses. A total of 2,460 squid were analyzed, which were captured during 15 exploratory fishing surveys in the Gulf of California during 2003 to 2006 and 2008. Of the total sample, 61% were female, 15% were male, and the rest were undifferentiated. Based on the frequency of the gonad developmental stages, the largest number of mature females was identified in February and October, whereas mature males were found in April and August. This result coincided with the gonadosomatic index. According to the histological analyses, we characterized 4 stages of oogenesis: previtellogenesis, vitellogenesis, postvitellogenesis with mature oocytes, and postspawning. We also characterized 6 substages of oocyte and 2 structural indicators of spawning: oogonia (Po0), previtellogenic oocyte primary (Pol), previtellogenic oocyte secondary (Po2), vitellogenic primary oocyte (Vol), secondary vitellogenic oocyte (Vo2), postvitellogenic oocyte (Pvo), postovulatory follicles, and atresia. Oocyte size among types showed significant differences (P < 0.05). The presence of postovulatory follicles, and oocytes of different sizes and various developmental stages throughout the study period indicates that the Panama brief squid has a synchronous ovarian development with multiple spawning. The size at first maturity (L₅₀) indicates that males (mantle length, 51 mm) mature at lengths shorter than females (mantle length, 85 mm).

In the current study, we examined the effects of histamine on survival and immune parameters of the Chinese mitten crab, Eriocheir sinensis. The crabs infected with the common bacteria pathogen Aeromonas hydrophila were injected with 0 µg histamine/g/crab, 1 µg histamine/g/crab, 50 µg histamine/g/crab, or 100 µg histamine/g/crab, and their survival after 96 h was recorded. The results showed that histamine alone had no influence on crab survival but can decrease survival of the crabs challenged with A. hydrophila after 36 h. In addition, the survival of the crabs injected with the high level (100 µg/g) of histamine was significantly greater than that of the lower level (50 µg/g) after 60–96 h (P < 0.05), but not different from that of the control. Immune parameters of the hemolymph in crabs, such as the total hemocyte count (THC), phenoloxidase (PO), acid phosphatase (ACP), alkaline phosphatase (AKP), and superoxide dismutase activity (SOD), were measured at 6 h, 12 h, and 24 h after histamine injection. Some immune parameters, such as PO and SOD, showed an increase, whereas THC, ACP, and AKP levels declined at 6 h. Surprisingly, after the injection of histamine, the crabs quickly released their pereiopods and began to twitch, and the number of the crabs with autotomy and spasm increased with the increasing histamine concentration (P < 0.05). This is the first report that indicates that histamine could lead to crab autotomy. The overall results of this study indicate that the effects of histamine on survival and the immune parameters of E. sinensis infected with A. hydrophila depend on its concentration.

The Dungeness crab is an important commercial and sports fishing species in Oregon. The fishery is regulated by sex, size, and season. This study examined whether female crabs are mating despite the removal of almost all legal-size male crabs each year. Of particular concern is whether large females are finding large enough mates. Females were collected from three Oregon fishing ports, dissected, and checked for evidence of mating. Captured male and female crabs were also measured to estimate population size distributions. The majority of female crabs examined (69%) mated in the collection year, and when combined with crabs that carried sperm from previous mating encounters (females store sperm), the percent of females that would have produced viable eggs was 83%. Crabs that definitely molted during the collection year showed higher mating success (95%). The largest females examined (carapace width, 160–169 mm) showed high mating success (84% mated in the collection year, 95% could have produced viable eggs). These numbers compare favorably with a similar survey conducted in northern California, in which 69% of molting females had mated. We conclude from the data that molting females in these Oregon fishing ports are finding mates successfully, regardless of size.

Reproductive biology, size at sexual maturity, and growth of the deep-water shrimp Solenocera melantho were studied in the East China Sea. The spawning season continues from July to November, with peaks during late August to November. Size at sexual maturity (CL₅₀), determined from the proportions of ovigerous females and of females with maturing ovaries, was estimated at 28.7 mm. The sex ratio was close to 1:1, with males slightly more abundant than females. Parameters of growth were estimated by the modified von Bertalanffy growth function, incorporating seasonal variation in growth. Females grew faster and reached a larger size at age than males (K = 1.14/y and L_∞ = 46.75 mm in carapace length for females, and K = 1.26/y and L_∞ = 33.6 mm in carapace length for males). Maximum life span was estimated at 2.43 y for females and 2.20 y for males. The S. melantho population in the East China Sea has different values of asymptotic length and growth coefficients in comparison with other local populations of this species.

The school prawn (Metapenaeus macleayi) is important among commercial prawn trawler operators, but its harvest is affected in a complex way by a number of interacting water quality, and other variables. In this study, using the Hawkesbury—Nepean River system as a case study, we use Pearson correlation and hierarchical agglomerative cluster analysis (HACA) to assess the influence of the selected water quality (n = 7), quantity (n = 1), and weather (n = 2) parameters on the prawn harvest. Using data records (n = 104) collected over a 9-y period, we found water temperature (r = 0.63, P < 0.01), dissolved oxygen (r = -0.59, P < 0.01), and rainfall (r = 0.26, P < 0.01) to be significantly correlated variables with prawn harvest. The HACA produced 3 distinct clusters of variables nutrient availability for prawns (the total nitrogen, the total phosphorus, reactive silicate, turbidity, and suspended solids), the physical river environment (temperature, rainfall, and river flow), and the biochemical river environment (dissolved oxygen and chlorophyll a). The study revealed that 2 key variables, viz., temperature and rainfall, representing the physical river environment are statistically significant in affecting prawn harvest in the study area. Therefore, from fishing industry point of view, the future river management need to focus on strategies that will improve the physical river environment, particularly to cope with the impacts of future peri-urban development and climate change scenarios.

We evaluated the effects of the dead probiotic Bacillus coagulons as a diet additive on growth performance, survival rate, digestive enzymes, and meat quality of the white shrimp Litopenaeus vannamei. Two treatment groups (T-1 and T-2) and a control group, each with 3 replicates, were established. The shrimp in the control were fed a basal diet, and those in T-1 and T-2 were fed with a basal diet containing viable and dead probiotic cells, respectively. After 50 days of culture, the addition of the probiotic resulted in greater (P < 0.05) final weight and daily weight gain, and survival rate. As for growth performance, the highest values (P < 0.05) were observed in T-1. Higher activities (P < 0.05) of protease, amylase, and lipase were also found in T-1 compared with T-2 and the control. No significant differences appeared in the muscle compositions of moisture, crude protein, and ash. However, the group that received viable probiotic showed greater (P < 0.05) muscle crude fat composition than that seen in the control group. In addition, greater (P < 0.05) inosinic acid content was observed in T-1. Our results showed that the dietary supplementation of both viable and dead probiotic, especially viable, can improve growth and survival rates of white shrimp.

Sexual dimorphism of the olfactory system is common in crustaceans; however, it has never been confirmed empirically to be sex dependent. In the current study, the growth pattern of aesthetasc (i.e., olfactory chemosensors of crustaceans) number in 4 protandric simultaneous hermaphroditic shrimp species in the genus Lysmata with 2 social systems—pair living (Lysmata amboinensis and Lysmata pederseni) and group living (Lysmata boggessi and Lysmata wurdemanni)—from male phase to euhermaphrodite phase were examined. The results show that the aesthetasc numbers of both male-phase and euhermaphrodite-phase shrimp are related in general to timing of sex change; in other words, those shrimp that change sex later have greater aesthetasc numbers than those that change sex earlier. This factor is the major reason contributing to the high variation in aesthetasc numbers in euhermaphrodite-phase shrimp. The aesthetasc number increased with shrimp growth during the male phase, but thereafter male-phase shrimp change into euhermaphrodite-phase shrimp and the aesthetasc number increased slowly at first and then stabilized, and even decreased in some. Our results suggest explicitly that the aesthetasc number in Lysmata shrimp is sex dependent and most likely related to their social environment as well.

Small, adult (19.50 ± 2.01g wet weight) Lytechinus variegatus (Lamarck, 1816) were fed 8 formulated diets with different protein (12–36% dry weight as fed) and carbohydrate (21–39% dry weight) levels. Each sea urchin (n = 8 per treatment) was fed a daily ration of 1.5% of the average body weight of all individuals for 9 wk. Akaike information criterion (AIC) scores were used to compare 6 different dietary composition hypotheses for 8 growth measurements. For each physical growth response, different mathematical models representing a priori hypotheses were compared using the AIC score. The AIC is one of many information—theoretical approaches that allows for direct comparison of nonnested models with varying numbers of parameters. Dietary protein level and protein:energy ratio were the best models for prediction of test diameter increase. Dietary protein level was the best model of test with spines wet weight gain and test with spines dry matter production. When the Aristotle's lantern was corrected for size of the test, there was an inverse relationship with dietary protein level. Log-transformed lantern to test with spines index was also best associated with the dietary protein model. Dietary carbohydrate level was a poor predictor for growth parameters. However, the protein × carbohydrate interaction model was the best model of organic content (percent dry weight) of the test without spines. These data suggest that there is a differential allocation of resources when dietary protein is limiting and the test, but not the Aristotle's lantern, is affected by availability of dietary nutrients.

We have cloned and characterized for the first time an allograft inflammatory factor 1 (Sn-AIF-1) from the Antarctic sea urchin. We report the cloning of Sn-AIF-1 cDNA and the characterization of its expression in coelomocytes after a bacterial challenge. The cDNA Sn-AIF-1 has a size of 608 bp and encodes a polypeptide of 151 aa. The deduced amino acid sequence has a putative size of 17.430 Da, an isoelectric point of 4.92, and shows 2 elongation factor handlike motifs that normally bind calcium ions. BLAST analysis revealed close matches with other known AIF-1. The deduced amino acid sequence of Sn-AIF-1 showed high homology with AIF-1 in vertebrates such as fish, mice, and humans; and in the case of invertebrates, the major degree of identity (55%) was with a predicted sequence of the purple sea urchin AIF-1, and 52% corresponded to a sponge. Expression of Sn-AIF-1 mRNA was analyzed by qPCR. Sn-AIF-1 mRNA expression was measured from coelomocytes after a bacterial challenge using RT-PCR and revealed that the gene was upregulated after 24 h. Sn-AIF-1 could participate in the inflammatory response, particularly in the activation of coelomocytes and their survival.

One of the most significant ecological and economic impacts of exotic species is associated with their role as vectors for the introduction of parasites into invaded areas. Exotic parasites may have devastating impacts on invaded ecosystems; moreover, invaders may also become hosts for aboriginal parasites, promoting native diseases that otherwise would not have emerged. During 2009 and 2010, exotic molluscs were collected from 27 sites in the Lower Great Lakes and their tributaries, the Finger Lakes, and Lake Oneida. Seven species of exotic molluscs were examined for the presence of trematodes, including the zebra mussel (Dreissena polymorpha), quagga mussel (Dreissena rostriformis bugensis), faucet snail (Bithynla tentaculata), European stream valvata (Valvata piscinalis), Asian clam (Corbicula fluminea), Chinese mystery snail (Cipangopaludina chinensis), and the New Zealand mudsnail (Potamopyrgus antipodarum). Most of the examined molluscs were infected with trematode larvae that may be harmful to their subsequent vertebrate hosts, including fish, birds, and mammals. These included Sphaeridiotrema sp. cercariae and Cyathocotyle bushiensis metacercariae from B. tentaculata, Echinostoma sp. cercariae from V. piscinalis, and echinostomatid metacercariae from Dreissena spp. and C. fluminea. Many exotic molluscs that were believed to be free of parasites have already acquired trematodes native to North America. Hotspots of trematode infections were recorded in the western basin of Lake Erie and in Lake Oneida, where several species of exotic molluscs had a high prevalence of trematodes, and thus potentially pose risk of transmission to definitive hosts.

Planktonic larvae of resident, oyster reef-associated decapods and fishes are subject to variable transport and retention whenever estuarine circulation is altered by freshwater inflow. Because freshwater inflow has the potential to advect larvae either toward or away from oyster reef settlement habitats, we compared the monthly distributions and abundances of larvae and postsettlement stages in Estero Bay, FL, under variable inflows during a 2-y period. Positive correlations between inflow and larval abundances of 2 species (Rhithropanopeus harrisii and Gobiesox strumosus) appeared to be caused by advection of upstream larvae downstream into the study area, whereas similar correlations with postsettlement juveniles of other species (Eurypanopeus depressus and Petrolisthes armatus) suggested bottom-up improvements to postsettlement survival. In contrast, the larvae of many species were advected seaward and away from oyster reef habitats during periods of elevated inflow, creating a spatial gap between the larvae and their landward settlement habitat. The size of this gap was larger for reefs that had greater exposure to freshwater inflows. Larvae displaced too far seaward would have a reduced window of opportunity to find oyster substrate for settlement, thus risking increased aberrant drift and predation loss. Because of the stationary nature of the settlement habitat, advection associated with elevated freshwater inflows was beneficial to some species and detrimental to others, producing winners and losers. The study also suggested that live oyster density was a good indicator of the density, biomass, and richness of oyster reef fishes and decapods. Evidence of temporal resource partitioning (successive peaks in larval densities) was present for those fishes that use empty oyster shell as sites for egg laying and nesting, although this pattern was present only during the first year of the study.