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Trap fisheries targeting invertebrates are economically important but many of the target species lack stock assessments. One reason for this is the difficulty of estimating density. One important means by which density can be estimated uses the catch rates of baited traps that are spaced at different distances. With declining spacing, the sphere of attraction will increasingly overlap, leading to reductions in catches, allowing for the estimation of the density that is catchable by traps on the seabed. Here we review the analytical methods adopted across a range of studies and find that no consensus on robust methods exists. We propose an analytical method that assumes the trapping area is circular and that the chance of catching an individual declines linearly with distance from the trap. We apply this method to estimate the density and the trapping radius of crabs and gastropods from real and simulated datasets. The method estimated a trapping radius of between 4 and 86 m, and densities that are up to 2.5 times less and 13 times greater than estimates provided in the original sources, illustrating the sensitivity to methodology. In conclusion, we provide and test a standardized method to estimate the density of benthic invertebrates. [ABSTRACT FROM AUTHOR]

Abstract Natural mortality estimates of harvested stocks are key parameters used in stock assessments to aid in understanding the dynamics of populations, but these estimates are difficult to obtain and have a high degree of uncertainty. Data from unfished populations, which is often rare, provide a unique and valuable opportunity to estimate natural mortality. This study provides estimates of natural mortality using multiple methods from an unfished whelk (Buccinum undatum) population using statolith ages which prove to be an accurate method to assess age of gastropods. Using statolith age‐frequency data, natural mortality for this unexploited Mid‐Atlantic Bight whelk population was estimated to be 0.45–0.60 year−1. Due to the unexploited state of this population, the mortality estimate in this study can be assumed to be a true reflection of natural mortality and thus compared with mortality estimates for populations under varying degrees of exploitation to understand how exploitation affects population dynamics.

Size composition of common whelk Buccinum undatum in its aggregations on sandy and stony grounds at the depth of 2–15 m is analyzed on the data of experimental fishing by scuba divers and traps in the Kislaya Guba and Ura Guba Bays in different seasons of 2004–2017. The size group with shell height > 60 mm was the most abundant (70 %) and formed 90 % of the total biomass. This group is recommended for fishery; the shell height of 60 mm is sug­gested as the minimal commercial size for common whelk in this area.

Development of the unmanaged waved whelk (Buccinum undatum) fishery on the Mid-Atlantic continental shelf of the United States has initiated investigation into fisheries-related biological and population attributes of the species in this region. Maturation and reproduction timing vary by location for this species and are likely linked to bottom water temperature. This study examined the seasonal fluctuations in relevant body metrics and gonadosomatic index in relation to bottom temperature to assess the timing of the reproductive cycle of the B. undatum population in the southern-most extent of this species' range in the Atlantic. To characterize variation over the maturation schedule, nine locations in the Mid-Atlantic Bight (MAB) were sampled five times between January 2017 and September 2017. Maturity was assessed macroscopically, with morphological methods, and via gonadosomatic indices. Male behavioral maturity estimates, based on a penis length to shell length index (PL50), were compared to estimates made using other methods for assessing maturity to test the efficacy of this commonly used ratio. Mature whelk were found in all months and peak reproductive activity was observed in spring and early summer. This timing suggests that ideal sampling to visually identify maturity to estimate size of maturity would be late winter or early spring. Unique oceanographic dynamics in the MAB, such as strong seasonal stratification results in large changes in annual bottom temperature which appears to be closely linked to the reproductive cycle in this region. Our data suggest that B. undatum in the MAB experience spawning and development at ~ 7–8 °C; temperatures warmer than Canadian populations and cooler than some UK conspecifics. To our knowledge, this is the first study to document the annual reproductive cycle of waved whelk in the United States. [ABSTRACT FROM AUTHOR]

Highlights • Size at sexual maturity was determined at five sites on the Eastern Scotian Shelf. • Significant differences exist in size at sexual maturity among different populations. • Sampled sites were 11–221 km apart from each other. • Size at sexual maturity ranges from 45 to 65 mm and varies among sexes. • Each exploited population should have a different minimum landing size. Abstract The waved whelk (Buccinum undatum) is commercially fished in the North Atlantic Ocean; the fishery is growing in Atlantic Canada. The species' oviparous reproduction limits dispersal, posing a challenge to fishery management at the meta-population level. The Minimum Landing Size (MLS) for B. undatum in Nova Scotia is set at 65 mm with intent to maintain an adequate spawning stock. The implicit assumption that the MLS approximates a size at which half the population has reached reproductive maturity (LM 50) is unjustified. We measured the LM 50 of the whelks sampled from commercial fishing catches during 2016 and 2017 at five sites on the Eastern Scotian Shelf located roughly 11–210 km apart. There were significant differences among all measured parameters including total shell length, LM 50 , sex ratio and parasitic prevalence. The latter was measured to investigate its effects on calculations of LM 50 and fishery regulations. The LM 50 was smaller than the MLS at all sites. The LM 50 for males ranged 45–64 mm, and 53–65 mm for females. The age at LM 50 was found to be consistent with other studies: 5–6 years for both sexes. The size-frequency distributions in most samples were approximately normally distributed. The sex ratio was within the range found in other studies but varied among sampling sites. The prevalence of castrating trematodes was found to be 2–26% in males and 5–25% in females. We suggest that the area-based, effort management model for the fishery should adopt locale-specific MLS values based on the LM 50 determined for sub-populations being exploited within specific areas of fishing access. [ABSTRACT FROM AUTHOR]

Calculating age and growth rate for the commercially important whelk, Buccinum undatum in the aid of fishery management has historically been undertaken using growth rings on the organic operculum. This is difficult due to their poor readability and confusion between two different sets of growth lines present. Recent work presented the calcium carbonate statolith as an alternative for age determination of B. undatum. Here we compare the use of statoliths and opercula, comparing their readability and creating growth curves for three distinct populations across the United Kingdom. Using these data, we also test the most appropriate growth equation to model this species. Lastly, we use oxygen isotope analysis of the shells to assign accurate ages to several individuals from each site. These data were used to test the accuracy of statolith and operculum ages. Statoliths, whilst more time consuming to process have improved clarity and accuracy compared with the opercula. This improved readability has highlighted that a Gompertz growth function should be used for populations of this species, when in past studies, von Bertalanffy is often used. Statoliths are a viable improvement to opercula when assessing B. undatum in the context of fishery monitoring and management. [ABSTRACT FROM AUTHOR]

This study was conducted to assess the potential application of ultrasonic treatment to enhance the tenderness of whelk (Buccinum undatum) meat. The optimum ultrasonic conditions for the maximum tenderization effect were determined using response surface methodology by a three‐level factorial Box–Behnken design for the optimization of three variables. The optimum conditions for the three variables found were as follows: ultrasound power at 200 W, treatment time for 9.6 min, and temperature at 45°C. The resulted tenderization effect was comparable to traditional enzymatic methods. Furthermore, disruption of muscle microstructure was observed in the ultrasonic‐treated whelk meat by scanning electron microscopy, while evaluations on physicochemical properties indicated the ultrasonic treatment has no significant undesirable effects on the quality of whelk meat including pH, water‐holding capacity, and lipid oxidation. In conclusion, this study showed the feasibility of ultrasonic treatment as a promising tenderization method for whelk meat without detrimental effects on its quality. Ultrasonic treatment was found to decrease the shear force of whelk meat significantly and cause the disruption of its muscle microstructure, with no significant undesirable effects on the quality of whelk meat (including pH, water‐holding capacity, and lipid oxidation) being observed, showing ultrasonic treatment might be a promising tenderization method for whelk meat. [ABSTRACT FROM AUTHOR]

The commercial fishery for common whelk ( Buccinum undatum L.) has expanded significantly in the Irish Sea since 1990 and continues to grow, particularly in Welsh waters and the Isle of Man territorial sea, with landings throughout the region increasing by 227% between 2011 and 2016. Whilst whelk populations are known to be vulnerable to localised overexploitation due to inherent life-history parameters, fisheries remain relatively unrestricted by conservation measures in comparison to other fisheries operating in the area. With the exception of the northernmost fishing ground between the Isle of Man and Scotland (Point of Ayre), the size-at-maturity (L 50 ) estimate for populations sampled during peak-aGSI (the months in which adjusted gonadosomatic index is highest) indicates that whelk are being fished before the time at first spawning throughout the study area. A correlation was detected between the size (total shell length) and depth, with smaller whelks found in deeper waters where there generally is greater fishing effort, although effort data is not available at a resolution to investigate this relationship quantitatively. No clear link between benthic infauna biomass and the average size (total shell length) or reproductive capacity (aGSI) of whelk sampled throughout ICES Area VIIa was found, indicating that the ecological energetics of whelk populations are more likely to be a function of scavenging opportunities than predation on benthic communities. A mixed cohort analysis utilized length-based data to infer a size-at-age relationship in the absence of direct age observations ( e.g. statolith rings), with whelk recruiting into the Isle of Man fishery five years after hatching. The evidence presented in this study suggests that, prior to recommending a MLS that will adequately protect the spawning stock biomass, L 50 values should be adjusted for pre-spawning growth between the ideal time of assessment (when aGSI values are at a peak) and the spawning season (when aGSI values decrease). [ABSTRACT FROM AUTHOR]

Recent expansion of the unmanaged waved whelk ( Buccinum undatum ) fishery within the United States Mid-Atlantic continental shelf region has prompted investigation into local life history parameters. Limited adult dispersal and lack of a planktonic larval stage has the potential to create spatially distinct populations with respect to size of sexual maturity and size frequency. During the summer of 2015, a comprehensive survey was undertaken to evaluate population structure, sex ratio, relative abundance, and size of sexual maturity for whelk in the Mid-Atlantic. Samples (n = 228) were collected from Georges Bank through the DelMarVa region using a modified scallop dredge at depths ranging from 27.4 to 112 m, with most whelk caught between 40–75 m, and peak abundances at 51–60 m. All whelk collected (n = 3877) were sexed, weighed, measured, and assessed for maturity. Sex ratios were skewed in favor of females in the south and balanced through the rest of the regions. Size of maturity ranged from approximately 56–73 mm and varied among regions and sex. Estimates of size of sexual maturity for B. undatum from other regions of the world were compiled, demonstrating that the size of maturity for this species is highly variable, and current minimum landing size regulations tend to fall below the estimated size of sexual maturity, potentially increasing the risk of recruitment overfishing. Overall, spatial variation in whelk phenotype suggests local adaptation in this species, indicating that regional management would be most appropriate. [ABSTRACT FROM AUTHOR]

A comparative immunological survey of cytotoxic properties of whole and cell-free haemolymph (plasma) was performed on four species of marine molluscs. Diverse target cells were used: auto- and heterologous mollusc haemocytes, starfish Asterias rubens coelomocytes, trematode Himasthla elongata rediae, and human erythrocytes. While all the four mollusc species were found to contain cytotoxic factors in their plasma, functional features of these molecules in bivalve and gastropod species are essentially different. Cell-free haemolymph of two clams, Mya arenaria and Mytilus edulis, contains pre-synthetized cytolytic complexes capable of immediate and generalized activation, leading to destruction of a broad range of target cells. On the contrary, two gastropod species, Buccinum undatum and Littorina littorea, possess haemolytic factors which display high specificity of recognition of receptor molecules on the target cells and slow cytolytic reaction. Overall, molecular strategies of cytolytic cascade activation in Bivalvia and Gastropoda can be described as low- and highly selective, respectively. [ABSTRACT FROM AUTHOR]

Analysis of simultaneously occurring live molluscs and empty shells of the whelk Buccinum undatum indicated similar abundance on the seabed making possible the estimation of recent natural mortality. Nearly all empty shells were occupied by hermit crabs Pagurus bernhardus and most of the remainder by Pagurus prideaux . P. bernhardus is highly selective for robust whelk shells, whereas anemone-protected P. prideaux use a range of smaller and thin-walled shells. Application of age size keys based on age reading of opercula surfaces permitted a tentative estimate of natural mortality of M = 1.34 on trap fishing grounds for brown crab in the southwest North Sea (whelks aged 4–7 years) and M = 0.85 and M = 0.63 for the fishing grounds on the Western Waters (whelks aged 4-7 years and 4-9 years respectively). Estimates of total mortality (Z), based on size-frequencies of live whelks, were Z = 1.35 (North Sea) and Z = 1.46 and 1.23 (Western Waters, aged 4-7 years and 4-9 years). Estimates of M for the North Sea might be biased by differences in trap selectivity between hermit crabs and live whelks. This is a novel approach that might be developed for whelk fisheries assessment and management, particularly using better age determination techniques. [ABSTRACT FROM AUTHOR]

There is little common rationale for the 45 to 75 mm total shell length (TSL) minimum landing sizes (MLS) for Buccinum undatum among countries in the Northeast Atlantic. Size at maturity and length frequency of B. undatum populations vary over small spatial scales; however, the driving mechanism for this is unknown. Size at maturity research for B. undatum dates back to the late 1980s; since then, there has been little consensus on laboratory methods or in which season to undertake the research. Here, we assess small-scale spatial variation in size at maturity over a year to identify the seasons that increase error in visual maturity estimates. We compare and contrast results from methods used in the literature to estimate maturity for B. undatum. Monthly, B. undatum samples were obtained from Welsh fishers between May 2013 and May 2014 from eight sites at four locations (n = 5080). All whelks were sexed, weighed, and measured, and up to 60 whelks from each location were assessed for maturity (n = 1659). Mature whelks were found in all months, with a peak in reproductive activity through summer and early autumn, followed by the onset of spawning in November. Size at maturity varied between sexes and sites, and ranged from 51 to 76 mm TSL. Whelks caught in shallow waters (0-10 m) matured at a smaller size than those from deeper waters (up to 60 m). Length frequency varied at each site suggesting that a single increase in MLS would impact fishers disproportionately. No methodology trialled was found without inherent errors when used in isolation, though a combination of methods proved ideal. The seasonal variation in maturity estimates suggested that assigning maturity is increasingly difficult outside annual reproductive periods and that prespawning is the ideal time to undertake visual gonad assessments for whelks. [ABSTRACT FROM AUTHOR]

The exploitation of the common whelk ( Buccinum undatum L.) has become an integral part of commercial fisheries in both Jersey and French waters. Since 2004 declining catches have been reported, and it has been suggested that existing management measures may not be effective. This study reports a further 8 years of annual monitoring of whelk catches from 2003 to 2011, using identical methodology and analysis as previous work. Jersey commercial whelk fishermen's logbook returns from 2007 to 2011, were also analysed for changes in effort and catch. Average catch per unit effort (CPUE) dropped by 36.7% from 3.3 kg per pot to 2.09 kg per pot. Since 2007, Fishermen's reported landings per unit effort for whelks, also dropped from 2.12 kg per pot to 1.75 kg per pot. Whilst a decline in catch rates of whelks greater than 44 mm shell length was reported earlier, this study also found catch rates for smaller whelks (<44 mm shell length) had declined by 54.5% from 0.44 kg per pot to 0.2 kg per pot, suggesting the start of possible recruitment overfishing. We found no statistical significance (repeated measures ANOVA) between the sample station grouping of ‘fished’ and ‘non-fished’, as reported previously, for either the small fraction or large fraction of the catch, both of which showed declines in CPUE. Analysis of fishermen's logbook returns showed that effort had varied over time and between statistical reporting areas. It is suggested that, given changes in fishing effort, an earlier grouping of fishing intensity is no longer relevant and we discuss the pitfalls of using such classifications and other arbitrary boundaries for spatial analyses which are then relied upon in making spatial planning and fisheries management decisions. More detailed spatial observations on fishing effort and trans-national sharing of data, along with relevant choices in joint management measures are required for the future sustainability of local whelk stocks. [ABSTRACT FROM AUTHOR]

The common whelk Buccinum undatum is widely distributed around the coast of the United Kingdom, and supports valuable fisheries in many areas around the English coast. A minimum landing size (MLS) of 45 mm currently applies in England and is generally viewed as a useful management measure to help support a sustainable whelk fishery. However, there is limited knowledge about regional variation in the size of sexual maturity (SOM) in English whelk populations. Whelks were collected at 12 different sites around the English coast and SOM estimates were compared to the current MLS. The national SOM was above MLS, and the proportion of mature whelks at the MLS was extremely low or zero at most sites. Significant differences were found in SOM between sites and between sexes within some sites. The current MLS may therefore provide little or no protection to the English spawning stock, and whelk populations may thus be vulnerable to recruitment overfishing. Site-specific values of SOM suggest that discrete populations may occur at each sampled location, despite some being geographically close to one another. We recommend that regional rather than national management measures are necessary to protect English whelk fisheries, and further research is needed to determine the appropriate MLS for each region. [ABSTRACT FROM AUTHOR]

The processes and factors which affect shell growth and repair in molluscs are poorly understood. In this study, the capabilities of shell growth and repair in the marine gastropod Buccinum undatum were investigated experimentally by implementing laboratory-controlled mechanical damage to the shell margin/lip. Three key factors, life stage (juvenile or adult), seawater temperature (5–15 °C) and food availability (unfed, weekly, or daily feeding), were investigated in a series of controlled laboratory experiments to establish their roles in the processes of shell growth and repair. Significant differences in rates of shell growth and repair between food and temperature regimes were observed, with the greatest difference occurring with different life stages. Rates of shell growth in non-damaged whelks were slightly faster but not significantly different from damaged individuals in any of the experiments. Tank-reared juveniles maintained in the highest seawater temperature regime (15 °C) displayed significantly faster rates of shell repair (F = 6.47, p < 0.05) than conspecifics held at lower seawater temperatures. Through characterising both biological and environmental factors affecting shell growth and repair, it is demonstrated that there are multiple aspects influencing shell growth and shell repair. It is important to be able to understand and establish differences in rates of growth to better manage this commercial species. • Whelks were reared successfully from egg masses in the laboratory and collected from wild samples • Repair was confirmed by marking the shells with Calcein, which is incorporated into the calcium carbonate and indicates when the damage occurred • When shells were experimentally damaged, juvenile whelks (<45 mm) repaired their shells faster than adult whelk (>45 mm) • An increased temperature saw an increase in shell repair rates • Food availability on shell repair rates was highly variable in some experiments [ABSTRACT FROM AUTHOR]

Developmental resource partitioning and the consequent offspring size variations are of fundamental importance for marine invertebrates, in both an ecological and evolutionary context. Typically, differences are attributed to maternal investment and the environmental factors determining this; additional variables, such as environmental factors affecting development, are rarely discussed. During intracapsular development, for example, sibling conflict has the potential to affect resource partitioning. Here, we investigate encapsulated development in the marine gastropod Buccinum undatwn. We examine the effects of maternal investment and temperature on intracapsular resource partitioning in this species. Reproductive output was positively influenced by maternal investment, but additionally, temperature and sibling conflict significantly affected offspring size, number, and quality during development. Increased temperature led to reduced offspring number, and a combination of high sibling competition and asynchronous early development resulted in a common occurrence of "empty" embryos, which received no nutrition at all. The proportion of empty embryos increased with both temperature and capsule size. Additionally, a novel example of a risk in sibling conflict was observed; embryos cannibalized by others during early development ingested nurse eggs from inside the consumer, killing it in a "Trojan horse" scenario. Our results highlight the complexity surrounding offspring fitness. Encapsulation should be considered as significant in determining maternal output. Considering predicted increases in ocean temperatures, this may impact offspring quality and consequently species distribution and abundance. [ABSTRACT FROM AUTHOR]

Temperature is arguably the primary factor affecting development in ectotherms and, as a result, may be the driving force behind setting species' geographic limits. The shallow-water gastropod Buccinum undatum is distributed widely throughout the North Atlantic, with an overall annual thermal range of below zero to above 22°C. In UK waters this species is a winter spawner. Egg masses are laid and develop when sea temperatures are at their coolest (4 to 10°C) indicating future climate warming may have the potential to cause range shifts in this species. In order to examine the potential impacts of ocean warming, we investigate the effects of temperature on the early ontogeny of B. undatum across a thermal range of 0 to 22°C. Each egg mass consists of approximately 100 capsules, in which embryos undergo direct development. Successful development was observed at temperatures ranging from 6 to 18°C. Rates of development increased with temperature, but the proportion of each egg mass developing successfully decreased at the same time. With increasing temperature, the mean early veliger weight increased, but the number of early veligers developing per capsule decreased, suggesting a negative impact on the number of crawl-away juveniles produced per capsule. Elemental analysis showed both carbon (C) and nitrogen (N) to increase with temperature in early veligers but not in hatching juveniles, indicating greater energy reserves are accumulated during early ontogeny to compensate for the higher energetic demands of development at higher temperature. The developmental plasticity observed in B. undatum suggests this species to be capable of adapting to temperatures above those it currently experiences in nature. B. undatum may possess a thermal resilience to ocean warming at its current upper temperature distribution limit. This thermal resilience, however, may come at the cost of a reduced offspring number. [ABSTRACT FROM AUTHOR]

Intracapsular development is common in marine gastropods. In many species, embryos develop alongside nurse eggs, which provide nutrition during ontogeny. The common whelk Buccinum undatum is a commercially important North Atlantic shallow-water gastropod. Development is intracapsular in this species, with individuals hatching as crawling juveniles. While its reproductive cycle has been well documented, further work is necessary to provide a complete description of encapsulated development. Here, using B. undatum egg masses from the south coast of England intracapsular development at 6 °C is described. Number of eggs, veligers and juveniles per capsule are compared, and nurse egg partitioning, timing of nurse egg consumption and intracapsular size differences through development are discussed. Total development took between 133 and 140 days, over which 7 ontogenetic stages were identified. The number of both eggs and veligers were significantly related to capsule volume, with approximately 1 % of eggs developing per capsule. Each early veliger consumed nurse eggs rapidly over just 3-7 days. Within each capsule, initial development was asynchronous, but it became synchronous during the veliger stage. No evidence for cannibalism was found during development, but large size differences between embryos developing within each capsule were observed, and occasionally 'empty' veligers were seen, which had not successfully consumed any nurse eggs. These results indicate a high level of competition for nurse eggs within each capsule during development in the common whelk. The initial differences observed in nurse egg uptake may affect individual predisposition in later life. [ABSTRACT FROM AUTHOR]

The objective of this study was to develop a means to reduce the capture of undersize waved whelk (Buccinum undatum) in small mesh (51-64 mm) conical traps. To achieve this, egress windows were incorporated above the bottom ring of a trap to produce openings of sufficient width to allow undersize whelk to be released as a string of traps is being hauled to the surface. Analysis of the passage of undersize whelk through three egress window sizes revealed that a 30 mm wide window was most suitable. Simulations of two vertical surge distances and two trap angles were carried out in a controlled environment to provide a better understanding of trap performance. Experiments revealed that when a trap is oriented at an angle of 40-45º a substantial percentage (29-36%) of undersize whelk can be removed at vertical surge distances of 0.3-1 m. Few (3-4%) legal size whelk were emitted at a trap angle of 40-45º and all whelk emitted from a trap were observed to pass through an egress window. Increasing the angle of the trap to 70-75º resulted in loss of legal size whelk through the entrance located on top of the trap. The results of these simple experiments are promising but require verification through fishery trials before they can serve management decisions. Trap modifications and a trap line configuration that will maximize the egress of undersize whelk during fishing trials are discussed. [ABSTRACT FROM AUTHOR]

The common whelk Buccinum undatum (Neogastropoda, Buccinidae) is widespread along the north Atlantic coasts of France. In west Cotentin (Normandy), an important local fishery exists that depends exclusively on this marine resource and represents about 90% of French whelk production. Despite successive restrictive measures, fishing yields have decreased since 2000. Shell length frequency distributions of Buccinum undatum caught in west Cotentin were studied in 2005 (N = 2910), in 2007 (N = 2032) and in 2009 (N = 4145) ranging from 7 to 85 mm. In order to preserve this fishery and to characterise the whelk stock at this site, the reproductive biology of this species was studied in relation to age, sex and size, for whelks of commercial size (45 to 61 mm) over the complete annual cycle in 2008. Age was determined by reading the number of operculum striae: animals between 45 and 59 mm had 2 to 4 striae. Four reproductive stages were defined for males and females on the basis of histological analysis. The time course of reproductive events was described according to size and sex: the highest percentages of ripe stages were found in October for both sexes. Spawning events occurred between October and December. The shell length that corresponded to 50% of animals having mature gonads (49 mm and 52 mm for males and females, respectively, corresponding to 3 and 4 years old animals) exceeded the minimal landing size (45 mm). Fifty percent maturity was reached for males in their third year and for females in their fourth year. Reproductive investment was evaluated by quantitative analysis of the gonadal thickness or surface and was found to be proportional to shell size. We found that less than 20% of females under 49 mm in length were sexually mature and that these produced only a few eggs. This information, collected in a major fishing area, should assist fishery management decisions. [ABSTRACT FROM PUBLISHER]

The fine structure and function of the excretory system and associated veins of the muricid Nucella lapillus have been studied and compared with those of the buccinid Buccinum undatum. It is argued that in both species the nephridial gland vein is a functional unit with the auricle as it is in Littorina, and that its sinuses provide a compensation sac for blood displaced from the mantle skirt on retraction of the snail into the mantle cavity. This may be typical of marine caenogastropods. The epithelium lining the tubules of the gland recaptures organic solutes from the urine at the start of the systemic circulation, and phagocytes in its sinuses (the blood gland) abstract macromolecules and toxins from the blood. The development of two different types of folds on the dorsal wall of the kidney in neogastropods and other carnivorous neotaenioglossans is correlated with adaptations of the foregut to diet and with feeding mechanisms in which a retractile proboscis is accommodated in the cephalic haemocoel. It does not necessarily reflect phylogenetic relationship. On the basis of the observations reported here it is concluded that the dorsal afferent renal vein and secondary folds of the kidney act primarily as a compensation sac for blood displaced from the cephalopedal haemocoel during retraction of the proboscis, or when the snail withdraws into its shell. Aggregates of haemocyanin form in these blood spaces at such times. The relationship between the two sets of folds, which interdigitate in pycnonephridians or are largely separate in meronephridians, is related to shell shape, proboscis type and foregut structure in different families. Loss of the anal gland in the buccinoideans is correlated with changes in the efferent renal veins, a reduction in the size of the rectal sinus and the reduction or loss of the gland of Leiblein. Extracellular bacteria occur in the anal gland of the muricid Ocenebra erinacea similar to those previously reported in Nucella, suggesting that their presence may be typically associated with the gland in the Ocenebrinae and possibly other muricids. [ABSTRACT FROM PUBLISHER]

The fates of a phenolic contaminant and its hydrocarbon precursor have rarely been compared, especially in an invertebrate species. Two groups of Buccinum undatum were exposed to equimolar amounts of pyrene and 1-hydroxypyrene over 15 d through their diets. Tissue extracts from the muscle and visceral mass were analyzed by liquid chromatography with fluorescence and mass spectrometry detection. Nine biotransformation products were detected in animals from both exposures. These included 1-hydroxypyrene, pyrene-1-sulfate, pyrene-1-glucuronide, pyrene glucose sulfate, two isomers each of pyrenediol sulfate and pyrenediol disulfate, and one isomer of pyrenediol glucuronide sulfate. These compounds represent a more complex metabolic pathway for pyrene than is typically reported. Diconjugated metabolites were as important in animals exposed to pyrene as in those exposed to 1-hydroxypyrene. Biotransformation products represented >90% of the material detected in the animals and highlight the importance of analyzing metabolites when assessing exposure. A mean of only 2 to 3% of the body burden was present in muscle compared with the visceral mass of both groups. The analytical methods were sufficiently sensitive to detect biotransformation products both in laboratory control whelks and in those sampled offshore. The tissue distribution of [14C]pyrene was also studied by autoradiography. Radioactivity was present primarily in the digestive and excretory system of the whelks and not in the gonads or muscle tissue. Environ. Toxicol. Chem. 2010;29:779–788. © 2009 SETAC [ABSTRACT FROM AUTHOR]

Abstract: In the Dutch Wadden Sea a whelk fishery existed from 1900 to 1970. The high post-war catches, following a period without fishery, and the subsequent decrease in catches when fishery was reopened, allowed us to estimate fishery mortality and recruitment. Information on natural mortality and growth, which were required in the estimation procedure, was obtained from previous studies elsewhere. Natural mortality could be calculated from an experiment with marked whelks in the Thames estuary. Age-length relations could be used from French investigations on whelks near the Channel Islands. The size of a potential whelk population could be estimated. Effects of fishery and possible causes of the disappearance of the whelk from the Dutch Wadden Sea are discussed. [Copyright &y& Elsevier]

Abstract: The principal inshore fishery in the southwest Irish Sea is currently for whelk Buccinum undatum, which expanded in the 1990s and yielded almost 10,000t in 2003. The fleet exploiting it consisted largely of old boats many of which previously used a variety of gears but which cannot any longer compete with more modern towing craft. Whelk is the only target species for the majority. The fishery is in open access and is not regulated and the paper examines the consequences of this for the fishers, particularly the problems associated with maintaining a way of life traditionally associated with remuneration by share rather than wage. Lack of regulation, it is argued, encourages a short term, opportunistic harvesting regime, which is not conducive to maintain a biologically sustainable fishery. [Copyright &y& Elsevier]

We evaluated sea urchin Strongylocentrotus droebachiensis predation on egg masses of the whelk Buccinum undatum. The urchin actively grazes on the egg masses, even as they are being deposited on the bottom. Whelks preferentially lay their egg masses on vertical areas where urchin densities are 4-fold less than on flat areas. This strategy is advantageous, as experimental trials showed that the loss in the mass of capsules was 4 fewer on walls than on flat areas. Nevertheless, a high proportion of egg masses on walls show damage from predation. Urchins provided with egg masses in the laboratory, ingested the capsules at a steady rate over a 9-d period (5 urchins ingested 2.8 g.d-1). Urchins provided agar discs that included a preferred alga and whelk capsule walls ingested the discs at a rate that was half that observed for discs that only included the alga. Discs that included the preferred alga and capsule contents were eaten at the same rate as discs that only included the alga. Thus, capsule walls, but not the capsule contents, provide a defence against urchin predation. Laying aggregate egg masses likely provides only a limited advantage, as the attachment surface does not increase with the number of egg masses deposited together, so the risk of detachment increases. Consideration of the interactions between urchins and whelks is important in managing the fisheries of the two species. [ABSTRACT FROM PUBLISHER]

Abstract: The common whelk, Buccinum undatum, was sampled from three areas; east and west Shetland, and the south coast of England. The largest whelk measured 122mm shell length (SL) and was recorded from west Shetland (mean 76mm) with the smallest animal recorded from south England, measuring 31mm (mean 54mm). Both east and south areas showed a peak in length–frequency distributions greater than the minimum landing size (MLS). The peak in the west was found below the MLS, which was the only site to show a bimodal length–frequency distribution. Fisheries recruitment was estimated to occur at 6 years of age for east, 7 for west, and 4 for south regions using estimates from von Bertalanffy growth curves. Imposex was not found to be prevalent in Shetland. Significant differences were noted between east and west Shetland, and between Shetland and south England, for all measured parameters of: SL, growth, age, flesh weight, and individual yield. These results suggest that a large-scale MLS for B. undatum is not practical when local fisheries are in differing states of maturity, as seen in Shetland and south England, and that micro-management within the fishery should be considered on a region by region basis to assess the practicality of such a management measure. [Copyright &y& Elsevier]