Cittarium Pica Research Articles

Last Interglacial coastal hydroclimate variability in Bermuda revealed by clumped isotope oyster sclerochronology

The islands of Bermuda preserve carbonates from several glacial and interglacial intervals with demonstrated potential for reconstructing past North Atlantic climate. Here, we describe new clumped and conventional stable isotope data from Dendostrea (oyster) shells collected from a Last Interglacial / Marine Isotope Stage 5e (MIS 5e) deposit. Interpretation of these and past data is supported by new amino acid racemization age dating results from nine localities around Bermuda.We find that the fossil oyster population on Verrill Island (within the present Great Sound of Bermuda) records MIS 5e temperatures and water δ18O values that are similar to modern. These data contrast with the much cooler temperatures and lighter reconstructed water δ18O values reconstructed for sites on the southern shore. This contrast may in part be due to timing, with the Verrill Island deposit plausibly representing an earlier and warmer portion of MIS 5e. The data also reflect meaningful, highly local differences in environment, with modern Great Sound shells perhaps living in partially restricted waters buffered from cooler and groundwater-influenced conditions along the South Shore. The mobility of Cittarium pica marine snails used in previous work likely also introduces exaggerated variability in those cases. Critically, incorporation of clumped isotope data across multiple sites and genera enables an understanding of Bermudian MIS 5e climate that would be meaningfully different if given data from only one site. We seek to illustrate both the complexities and potential of working with clumped isotope paleoclimate data from coastal deposits.

Congruence between microsatellite loci, SNPs, and COI gene reveals a phylogeographic break in the southern Caribbean Sea: The case of West Indian top shell Cittarium pica (Gastropoda: Tegulidae)

It has been proposed that species associated with shallow rocky bottoms in the southern Colombian Caribbean Sea are affected by two biogeographic barriers: the Magdalena River plume (MRP) and the combination of the absence of rocky bottoms and the almost permanent upwelling in the Guajira peninsula (ARB+PUG). We evaluated whether these barriers had generalized genomic effects on the phylogeographic structure of the West Indian top shell (Cittarium pica), a crucial fishery resource in many areas of the Caribbean Sea. Ten species-specific microsatellite loci, 55,112 SNPs from ddRADseq, and COI gene were used on samples of C. pica collected at five Colombian localities (Cabo de la Vela; Santa Marta; Cartagena; Isla Fuerte; and Capurganá). Genetic structure analyses performed for microsatellite and SNP loci indicated that there are three genetic groups of C. pica in Colombia (pop 1: Cabo de la Vela; pop 2: Santa Marta; pop 3: Cartagena+Isla Fuerte+Capurganá). However, both SNPs and COI gene were congruent in showing a phylogeographic break caused by only the ARB + PUG (AMOVA: ΦCT-SNP=0.224, p < 0.05; ΦCT-COI=0.722, p < 0.05), which was confirmed by the maximum-likelihood and network trees. In contrast, MRP was shown to be a permeable barrier to gene flow. Demographic history analysis indicated that C. pica experienced historical changes in population size during the last glaciation period. Cittarium pica is a biological model to demonstrate how the ARB + PUG barrier could affect marine organisms living in shallow rocky habitats, mainly those lacking larvae or having a short-lived larval phase in the southern Caribbean Sea. Finally, some recommendations for fisheries management and conservation C. pica populations are discussed.

A Comparative Phylogeography of Three Marine Species with Different PLD Modes Reveals Two Genetic Breaks across the Southern Caribbean Sea.

The comparative phylogeography of marine species with contrasting dispersal potential across the southern Caribbean Sea was evaluated by the presence of two putative barriers: the Magdalena River plume (MRP) and the combination of the absence of a rocky bottom and the almost permanent upwelling in the La Guajira Peninsula (ARB + PUG). Three species with varying biological and ecological characteristics (i.e., dispersal potentials) that inhabit shallow rocky bottoms were selected: Cittarium pica (PLD < 6 days), Acanthemblemaria rivasi (PLD < 22 days), and Nerita tessellata (PLD > 60 days). We generated a set of SNPs for the three species using the ddRad-seq technique. Samples of each species were collected in five locations from Capurganá to La Guajira. For the first time, evidence of a phylogeographic break caused by the MRP is provided, mainly for A. rivasi (AMOVA: ΦCT = 0.420). The ARB + PUG barrier causes another break for A. rivasi (ΦCT = 0.406) and C. pica (ΦCT = 0.224). Three populations (K = 3) were identified for A. rivasi and C. pica, while N. tessellata presented one population (K = 1). The Mantel correlogram indicated that A. rivasi and C. pica fit the hierarchical population model, and only the A. rivasi and C. pica comparisons showed phylogeographic congruence. Our results demonstrate how the biological traits of these three species and the biogeographic barriers have influenced their phylogeographic structure.

Settlement and culture of post-larvae, spat and juveniles of the West Indian topshell, Cittarium pica (Linne, 1758)

The settlement, survival and growth rates of C. pica post-larvae, spat and juveniles were evaluated under different culture conditions. The factorial effect of six stimuli (low temperature, γ-aminobutyric acid, potassium chloride, hydrogen peroxide, dibromo methane, and coralline algae extract), five types of biofilm substrates (artificial, artificial with coralline algae, artificial with congener mucus, benthic microalgae, and microalgae with congeners mucus) and five stimulation times (6, 12, 24, 36 and 72 h) on the larval settlement of the topshell were assessed. In addition, growth and survival rates of post-larvae fed with artificial biofilm and benthic microalgae were compared. Similarly, growth and survival rates were assessed in spat cultured in different environments (outdoor and indoor), and juveniles grown in concrete tanks with different finished of the inner walls (gray rough finish, and white smooth walls with epoxy paint). A higher larval settlement was observed in substrates with artificial biofilm exposed to cold water (20 °C) for 24 h. Treatments with the stimulus of KCl and dibromo methane had toxic effects on larvae. There were not differences in the shell length of the settled larvae between stimuli, substrata or exposition time. Post-larvae fed with artificial biofilm had survival and growth rates similar to those maintained with benthic microalgae biofilm. The spat that were cultured in outdoor conditions showed a higher growth rate than those kept indoor, but the survival was similar in both cases. Finally, juveniles grown in tanks with rough, gray concrete inner walls had higher growth and survival rates, compared to those held in tanks with smooth white finish. The improvements obtained in growth and survival of post-larvae, spat and juveniles of C. pica suggest that there is a great biological potential for its wild populations restocking and for its aquaculture in sea-based systems.

Seasonally Variable Aquifer Discharge and Cooler Climate in Bermuda During the Last Interglacial Revealed by Subannual Clumped Isotope Analysis

AbstractFaunal analog reconstructions suggest that Last Interglacial (MIS 5e) sea surface temperatures were cooler around Bermuda and in the Caribbean than modern climate. Here we describe new and revised clumped isotope measurements of Cittarium pica fossil shells supporting previous findings of cooler than modern temperatures in Bermuda during the Last Interglacial. We resolve temperature and δ18Ow differences between two closely located and apparently coeval sites described in Winkelstern et al. (2017), https://doi.org/10.1002/2016pa003014 through reprocessing raw isotopic data with the updated Brand/IUPAC parameters. New subannual‐resolution clumped isotope data reveal large variations in δ18Ow out of phase with seasonal temperature changes (i.e., lower δ18Ow values in winter). Supported by modern δ18Ow measurements identifying similar processes occurring today, we suggest past variations in coastal δ18Ow were driven by seasonally variable freshwater discharge from a subterranean aquifer beneath the island. Taken together, our results emphasize the importance of δ18Ow in controlling carbonate δ18O, and suggest that typical assumptions of constant δ18Ow should be made cautiously in nearshore settings and can contribute to less accurate reconstructions of paleotemperature.

Demography and shell use of the terrestrial hermit crab Coenobita clypeatus Fabricius, 1787 (Decapoda: Anomura: Coenobitidae) in two marine protected areas in Puerto Rico

Abstract Individuals of the terrestrial hermit crab Coenobita clypeatus Fabricius, 1787 use different gastropod shells for shelter during their life span. Availability of shells affects population traits, including density and size structure, influencing their fitness and survival. Locality and human presence can induce variation in the diversity and size of gastropod shells, influencing available shells for hermit crabs. We assessed how the diversity, size, and abundance of the occupied species of gastropod shells affect the density and demography of C. clypeatus in two marine protected areas (MPA) with different recreational use in Puerto Rico, Manatí (high) and Mona Island (low). We also evaluated the relationship between three shell traits (length, width, and aperture length) and the length of the crab chela as a size proxy. We did not find differences in the sex ratio. The density and median chela sizes were higher in crabs from Manatí. In Mona, however, they reached larger sizes. The diversity of occupied shell species was higher in Manatí than in Mona. Dimensions of occupied shells differed between genera and between study sites, and they scaled positively with hermit crab size. Differences in shells diversity, sizes, and abundance between MPAs might cause differences in density and demography of C. clypeatus. We only found large shells of Cittarium pica (Linnaeus, 1758), the only species occupied by larger individuals, occupied by hermit crabs in Mona. The low abundance of C. pica shells in Manatí might have affected the size of hermit crabs in this locality. Our in situ findings suggest that hermit crabs need larger shells to reach larger sizes as previously shown, and that location and the degree of human intervention might influence the availability of gastropod shells. Our study is the first attempt to characterize the demography and gastropod shells used by hermit crabs in Puerto Rico.

Effect of diet and water quality on the energetic physiology of the West Indian top shell Cittarium pica

The West Indian top shell Cittarium pica is a gastropod species currently regarded as threatened mainly due to overfishing of wild stocks. Substantial efforts have been invested in the experimental culture of this mollusk for resource conservation, as well for commercial production. In order to determine the suitable culture conditions for this species, the present study addressed the effect of diet and water quality on the energetic physiology of C. pica. Experimental animals were fed with different diets (fresh seaweed, benthic microalgae and artificial biofilm), and exposed to different rates of water renewal (10, 50, 100 and 300% h−1), and levels of salinity (25, 30, 35 and 40 ppt), temperature (22, 27 and 32 °C) and ammonia concentration (2.5, 8.0, 20.0 and 40.0 μg NH3-N L−1). Under such conditions, individual measurements of ingestion rate (IR), absorption efficiency (AE), oxygen consumption rate (OCR), ammonium excretion rate (UR), mucus production rate (MR) and scope for growth (SFG), were conducted. Both, juveniles and adults exhibited a micro-grazing feeding behavior. IR was affected by diet, water renewal and salinity, while AE was influenced by all the factors tested. OCR was only affected by ammonia concentration, while UR was influenced by salinity, temperature and ammonia concentration. Finally, MR was affected by all the factors tested, except for diet. The highest SFG performances were obtained when top shells were fed artificial diet biofilm, and maintained at relatively high levels of salinity (35–40 ppt) and temperature (27–32 °C), and intermediate rates of water renewal (50–100% h−1), oxygen saturation (> 70%) and ammonia concentration (2.5–40.0 μg NH3-N L−1). In general, such responses were associated with high IR and/or AE values, while energy losses in terms of OCR, MR and UR did not show a significant influence.

Effect of body size on the energetic physiology of the West Indian top shell Cittarium pica (Linnaeus, 1758)

Cittarium pica is an endangered Caribbean gastropod of ecological and economic importance. In order to provide the basis for the aquaculture development and/or population management of this species, the relationships among its body size and physiological variables associated with the energetic balance were assessed. Individual measurements of rates of egestion (ER), ingestion (IR), absorption (AR), oxygen consumption (OCR), ammonia excretion (UR), mucus production (MR), absorption efficiency (AE) and scope for growth (SFG), were carried out on specimens between 0.01 and 12.07 g of dry weight of the soft parts (DW) under controlled laboratory conditions. Most of the variables showed positive potential relationships with the DW of the animals (ER mg h -1 = 1.51 DW 0.37 , IR mg h -1 = 4.13 DW 0.32 , AR = 2.56 DW 0.30 , OCR mL O 2 h -1 = 0.38 DW 0.74 , UR μg NH 4 -N h -1 = 19.17 DW 0.78 , MR mg h -1 = 1.28 DW 0.14 and SFG = 36.92 DW 0.22 ). AE did not show any relationship with this variable. The large snails had faster input and output of energy compared to the small specimens, also having proportionally greater energetic expenditures, mucus production, and energetic balance.

Nursery culture of wild and hatchery-produced juveniles of the West Indian top shell, Cittarium pica, fed microalgal and artificial biofilms

Cittarium pica is an overexploited Caribbean top shell that is being produced at an experimental level by aquaculture for conservation purposes. To optimise nursery culture, the growth and survival of wild and hatchery-produced juveniles were assessed after feeding with different biofilm diets. The following three diets were tested over a 6-month period: (1) a microalgal biofilm of Nitzschia sp. and Tetraselmis chuii; (2) an artificial biofilm of dry seaweeds, Padina gymnospora and Laurencia obtusa, and the cyanobacterium Spirulina sp.; and (3) a mix of the microalgal and artificial biofilms. The biofilms were prepared and supplied on folded PVC plates, and treatments were administered in triplicated 10-L aquaria with down-welling systems at 25 ± 1 °C and a salinity of 36.5 ± 0.5 ppt. Higher growth rates were obtained in juveniles fed diets containing artificial biofilms, which had high protein and energy contents, whereas survival rates were higher in juveniles fed the mixed diet. The relatively high growth and survival values suggest that the nursery culture can be improved by feeding with the mix of microalgal and artificial biofilms and that the temporary translocation of wild juveniles to nursery conditions can be a tool for population enhancement.

Experimental culture of larvae, post-larvae and juveniles of the West Indian top shell, Cittarium pica (Linnaeus 1758)

The West Indian top shell, Cittarium pica, is an endangered vetigastropod of ecological and commercial value from the Caribbean. In order to assess the use of aquaculture as a tool for its sustainable production and conservation, embryos were produced in hatchery and experimentally cultured until juveniles under different conditions. Embryos were incubated under two temperatures (25 and 29°C) and six densities (0.3, 0.6, 1.0, 4.0, 9.0 and 37.0% of bottom-coverage). Larvae were reared under different temperatures (25 and 27°C), densities (0.5, 1, 1.5 and 10 larvae/ml) and culture systems (static and down-welling). Post-larvae were obtained in three different settling conditions, and the early juveniles were cultured supplying fresh seaweed (Laurencia obtusa and Padina gymnospora), natural multi-specific biofilm and Cylindroteca sp. biofilm. The growth and survival of embryos and larvae were not affected by temperature, but they were affected by density. Higher values were obtained at low densities (<1% of embryos bottom-coverage and <1 larvae/ml), except for the growth of larvae, which was similar among treatments. Higher larval survival was recorded using the static culture system, and higher percent of post-larvae recovered was associated with lower density of crawling veliger (0.2 and 0.1/ml), while its higher growth rate was related to the use of biofilms with conspecific mucus and low water-flow (50%/h). The type of food tested did not affect the juvenile growth, but higher survival was obtained in those fed with seaweed than with multi-specific biofilm.

Ecología poblacional de Cittarium pica (Gastropoda: Trochide) en la isla de San Andrés, Reserva Internacional de Biósfera, Seaflower.

Cittarium pica is a conspicuous gastropod of the rocky coastlines of the Caribbean. Given its importance in the diet of Caribbean communities, it has been over-exploited, even reaching extinction in some places, and the species has been included in the red lists of marine invertebrates in some countries. Its fishery in San Andres Island-Colombia is artisanal without any regulation, leading to a decrease in its population. Taking into account the socio-economic, cultural and ecological importance of C. pica and its vulnerability to extinction, it is urgent to develop management actions directed to increase the resilience of the species and its sustainability as a fishery resource. To assess the current population state of C. pica from San Andrés Island, we estimated size structure, sex structure, maturation size, and growth parameters, based on length-frequency data analysis. From September to December 2013, and January to March 2014, we randomly collected 458 individuals at eight representative sites of the rocky shores of the island. We measured the longest diameter of the shell base, determined the sex by the color of the gonad, and thus determined the minimum maturation size. We found, that 80 % of the population consisted of small individuals &lt; 25.5 mm sizes. The sex ratio was 1:1 except in November, where males were more abundant. The minimum size at the beginning of maturity for both sexes was 14.07 mm. The growth parameters of von Bertalanffy: K (0.730 yr-1), L∞ (110.78 mm) and Φ (3.95) were higher when compared to other populations of the Caribbean. The total mortality was 3.39 yr-1, while natural and fishing mortalities were 1.02 yr-1 and 2.36 yr-1, respectively. The maximum annual recruitment pulse was estimated for June, and the maximum exploitation rate for a sustainable yield was between 0.563 and 0.640, when the catch size was greater than 40 mm or 50 mm, respectively. The exploitation rate was estimated in 0.70, suggesting a strong extractive resource pressure. With these results we recommend the closure of the fishery and constant monitoring to promote and the population recovery is verified. Until a monitoring shows that the population recovers on the island.Until a monitoring shows that the population recovers on the island.

Meltwater pulse recorded in Last Interglacial mollusk shells from Bermuda

AbstractThe warm climate of Bermuda today is modulated by the nearby presence of the Gulf Stream current. However, iceberg scours in the Florida Strait and the presence of ice‐rafted debris in Bermuda Rise sediments indicate that, during the last deglaciation, icebergs discharged from the Laurentide Ice Sheet traveled as far south as subtropical latitudes. We present evidence that an event of similar magnitude affected the subtropics during the Last Interglacial, potentially due to melting of the Greenland Ice Sheet. Using the clumped isotope paleothermometer, we found temperatures ~10°C colder and seawater δ18O values ~2‰ lower than modern in Last Interglacial Cittarium pica shells from Grape Bay, Bermuda. In contrast, Last Interglacial shells from Rocky Bay, Bermuda, record temperatures only slightly colder and seawater δ18O values similar to modern, likely representing more typical Last Interglacial conditions in Bermuda outside of a meltwater event. The significantly colder ocean temperatures observed in Grape Bay samples illustrate the extreme sensitivity of Bermudian climate to broad‐scale ocean circulation changes. They indicate routine meltwater transport in the North Atlantic to near‐equatorial latitudes, which would likely have resulted in disruption of the Atlantic Meridional Overturning Circulation. These data demonstrate that future melting of the Greenland Ice Sheet, a potential source of the Last Interglacial meltwater event, could have dramatic climate effects outside of the high latitudes.

Spawning and early development of the West Indian top shell,Cittarium pica(Linnaeus, 1758), under ex-situ conditions

The West Indian top shell, Cittarium pica , is an endangered vetigastropod from the rocky intertidal Caribbean. In order to provide a basis for its hatchery-production as a conservation tool, spawning and early development were evaluated under ex-situ conditions. Spawning response was monitored during different lunar phases with application of physical and chemical stimuli – such as changes in temperature salinity and desiccation, exposure to UV irradiated water and chemical stimulation with Tris and hydrogen peroxide. Spawning response was obtained in association with daytime, new moon, flooding and high tides. Use of physical and chemical stimuli did not elicit any spawning response. Adults conditioned in the hatchery for one year did not spawn. Spawning of males and females was simultaneous and frequently intermittent. On average, percentage and size of spawn was higher for males than females. Fecundity was positively correlated with total female wet weight, with an average value of 149 000 oocytes per female. Embryonic and larval development was reported in detail. Results suggest that there is a high potential to use the controlled ex-situ reproduction of C. pica as a conservation tool, since gamete and larvae were repeatedly obtained from wild adults collected days before new moon following a circadian endogenous pattern applying simple protocols of spawning, fertilization and incubation.

Dislodgement force and shell morphology vary according to wave exposure in a tropical gastropod (Cittarium pica)

ABSTRACTWave exposure has strong influences on population density, morphology and behaviour of intertidal species in temperate zones, but little is known about how intertidal organisms in tropical regions respond to gradients in wave exposure. We tested whether dislodgement force and shell shape of a tropical gastropod, Cittarium pica, differs among shores that vary in wave exposure. After adjusting for body size, we found that C. pica from exposed shores required greater dislodgement force to remove them from the shore, had slightly larger opercula (the closure to the shell aperture), and were slightly squatter in shape (reduced in shell height relative to shell width) than C. pica from sheltered shores. These morphological adjustments are consistent with those observed in temperate gastropods, which are argued to represent adaptive responses to the risk of mortality associated with dislodgement.

Shellfish as reservoirs of bacterial pathogens

Shellfish comprises a variety of animals including bivalves – oysters, clams, quahogs, scallops, mussels, and others including crustaceans – lobsters, crabs, and shrimps. Shellfish naturally found in Grenada, an island nation in the Caribbean, include: blue land crabs (Cardisoma guanhumi), clams (Mercenaria mercenaria), oysters (Isognomon isognomon), queen conchs, also called “lambi” (Strombus gigas), and whelks (West Indian top shell) (Cittarium pica), all of which are used for human consumption in this country. Bacteria are ubiquitous in the marine environment. Shellfish can be a source of commensal bacteria that can be pathogenic to shellfish, as well as those pathogenic to humans. Raw and partially cooked molluscan shellfish (clams, oysters, and mussels) have a long history as vectors of infectious agents[1]. According to Potasman et al.[2], the earliest reports of shellfish-transmitted diseases were documented in the late 19th and early 20th century. Apart from typhoid fever, the most notable examples include Vibrio species, which account for 20% of all outbreaks of shellfishassociated human disease. Other bacteria are Salmonella species, Shigella species, Plesiomonas shigelloides, and Listeria species[2]. Several Vibrio species native to both marine and estuarine environments, have been identified as the causative agents of shellfish-associated human illnesses. These include Vibrio parahaemolyticus (V. parahaemolyticus), Vibrio vulnificus (V. vulnificus), Vibrio cholerae non-O1, Vibrio cholerae, Vibrio cholerae O1, Vibrio fluvialis (V. fluvialis), Vibrio hollisae, Vibrio mimicus, Vibrio alginolyticus (V. alginolyticus), and unidentified or miscellaneous Vibrio species. Among these, all except V. vulnificus, are associated with gastroenteritis of varying severity[1]. Oysterassociated V. vulnificus septicemia and death were first reported in 1975[3]. Another bacterium of public health concern is Salmonella. Compared to vibrios, there have been much less studies on Salmonella in various shellfish. Setti et al.[4] studied the dynamics of Salmonella contamination in the coastal areas of Agadir, a populous region of Southern Morocco where shellfish production is important to the local economy. Salmonella enterica (S. enterica) serovar Kentucky was found almost exclusively in mussels, whereas Salmonella blockley was found in mussels and sediment samples. Identification of Salmonella to serovar level is required ARTICLE INFO ABSTRACT

EXPLOTACIÓN, USOS Y ESTADO ACTUAL DE LA CIGUA O BURGAO CITTARIUM PICA (MOLLUSCA: GASTROPODA: TROCHIDAE) EN LA COSTA CONTINENTAL DEL CARIBE COLOMBIANO

The West Indian topshell, Cittarium pica is a common and conspicuous gastropod that thrives in Caribbean intertidal rocky shores and has been used for food by men since pre-Columbian times. Although, the exploitation of this resource is practiced only by artisanal fishermen and mainly for self-consumption, its abundance has noticeably reduced in the last ten years, so the species has been included in the endangered animal lists of several Caribbean countries, including Colombia. The present study was carried out to assess the current status of the population of C. pica along the Colombian Caribbean mainland and to describe the overall exploitation level and uses of this resource in recent times. In order to achieve so, Colombian Caribbean coast was divided into five zones according to the established distribution range of the species: 1-Urabá chocoano, 2-Isla Fuerte, 3-Cartagena and Rosario Islands, 4-Santa Marta and Tayrona Natural National Park, 5-La Guajira. In each one of the zones opinion polls among local inhabitants were conducted. A series of samples from representative stations were obtained in order to determine the abundance, density and size structure of the C. pica population. The fishing pressure on the resource is different between the sectors, being greater in Santa Marta and Tayrona Natural National Park, Urabá chocoano, and Cartagena and Rosario Islands. The main use given to C. pica is as dietary complement of the local population, but the flesh and shells are commercialized at times. Shells are sold to artisans and used for “souvenirs” and handcraft manufactures. The mean ecological density of C. pica in the entire study area was 5.38 Ind/m2 (± 0.82), with significant differences between sectors and between the stations within a sector as well. The size structure of the population (mean size = 25.08 mm ± 4.71, mode = 11.10 mm) suggests that in general the resource is being over-exploited in the Colombian Caribbean. This result confirms that C. pica is an endangered species in Colombia and its status as “vulnerable” in the red list should be maintained.

Periodicity of extinction and recolonization of the West Indian topshellCittarium picain the Quaternary of Bermuda (Gastropoda: Trochoidea)

Hermit-crab transported shells of the West Indian top shell Cittarium pica occur in numerous terrestrial fossil deposits on Bermuda, which is the most remote outpost of this Caribbean species. Cittarium is so far known only from deposits of interglacial ages corresponding to marine isotope stages (MIS) 11, 9, 5e, and 1 (Holocene). In at least the cases of MIS 11 and 5e, Cittarium appears at the very beginning of the interglacial. The species is definitely absent from well-stratified cave deposits of the last glacial (MIS 4–2). It is hypothesized that colder sea-surface temperatures (SSTs) during glacial periods caused Cittarium to be extirpated on Bermuda, and that it has made at least four independent colonizations of the island in the past 400 000 years. Because of the limited larval life of Cittarium, the window for colonization may be a very narrow period at the onset of interglacials when the SST has risen sufficiently to make Bermuda habitable but the velocity of the Gulf Stream is still sufficiently rapid to transport viable larvae from the Bahamas. © 2013 The Linnean Society of London, Biological Journal of the Linnean Society, 2013, 110, 235–243.

Genetic structure and connectivity patterns of two Caribbean rocky-intertidal gastropods

The extent of gene flow in Caribbean marine communities has been investigated primarily in taxa from coral reef habitats, particularly in corals and reef fishes. Results from empirical population genetic studies in those taxa have indicated the presence of an east –west genetic break between 678 and 708W longitude, and isolation of populations in the Bahamas. Hydrodynamic modelling has further suggested the presence of four connectivity regions that may contribute to genetic isolation. In this study we test for the presence of genetic structure in two gastropods (Cenchritis muricatus and Echinolittorina ziczac) from poorly sampled rocky intertidal habitats, using mitochondrial sequence data. Significant genetic structure was found in C. muricatus (Snn ¼ 0.29, P , 0.001; Fst ¼ 0.022, P , 0.001), but not in E. ziczac (Snn ¼ 0.17, P ¼ 0.48; Fst ¼ 0.022, P ¼ 0.48), in spite of similar larval life histories. The pattern of differentiation does not match a simple east– west model in either species, nor a four-region model, nor do the Bahamas show evidence of isolation. However, the genetic differentiation of Bonaire from other sites that is observed in C. muricatus and E. ziczac is consistent with the previously observed isolation of this location in the trochid gastropod Cittarium pica.

Population Genetics of a Trochid Gastropod Broadens Picture of Caribbean Sea Connectivity

BackgroundRegional genetic connectivity models are critical for successful conservation and management of marine species. Even though rocky shore invertebrates have been used as model systems to understand genetic structure in some marine environments, our understanding of connectivity in Caribbean communities is based overwhelmingly on studies of tropical fishes and corals. In this study, we investigate population connectivity and diversity of Cittarium pica, an abundant rocky shore trochid gastropod that is commercially harvested across its natural range, from the Bahamas to Venezuela.Methodology/Principal FindingsWe tested for genetic structure using DNA sequence variation at the mitochondrial COI and 16S loci, AMOVA and distance-based methods. We found substantial differentiation among Caribbean sites. Yet, genetic differentiation was associated only with larger geographic scales within the Caribbean, and the pattern of differentiation only partially matched previous assessments of Caribbean connectivity, including those based on larval dispersal from hydrodynamic models. For instance, the Bahamas, considered an independent region by previous hydrodynamic studies, showed strong association with Eastern Caribbean sites in our study. Further, Bonaire (located in the east and close to the meridional division of the Caribbean basin) seems to be isolated from other Eastern sites.Conclusions/SignificanceThe significant genetic structure and observed in C. pica has some commonalities in pattern with more commonly sampled taxa, but presents features, such as the differentiation of Bonaire, that appear unique. Further, the level of differentiation, together with regional patterns of diversity, has important implications for the application of conservation and management strategies in this commercially harvested species.

TBT pollution and effects in molluscs at US Virgin Islands, Caribbean Sea

An almost ubiquitous occurrence of imposex and butyltins in the molluscs from US Virgin Islands gives evidence to a widespread contamination with the antifouling agent tributyltin (TBT), which most likely is related to a relatively intense ship traffic. Three different muricid neogastropod species Thais deltoidea, Thais rustica and Purpura patula all seem to have potential as suitable and sensitive bioindicators for assessing levels and effects of TBT pollution in coastal areas including coral reefs in the Caribbean Sea. However, considerable interspecies differences in especially accumulation potential of butyltins were seen in this study. Furthermore, a high accumulation potential of TBT in the edible gastropod West Indian topshell ( Cittarium pica) was found, despite that no signs of imposex were observed in this archaeogastropod species.