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Chunde Wang - One of the best experts on this subject based on the ideXlab platform.

  • transcriptomic and proteomic analyses of genetic factors influencing adductor muscle coloration in qn orange Scallops
    BMC Genomics, 2019
    Co-Authors: Junlin Song, Chunde Wang
    Abstract:

    Background Color polymorphism, a high-valued trait, is frequently observed in molluscan shellfish. The QN Orange Scallop, a new Scallop strain successively selected from the interspecific hybrids of the bay Scallop (Argopecten irradians irradians) and the Peruvian Scallop (Argopecten purpuratus), is distinguished from other Scallops by its orange adductor muscles. In this study, to reveal the mechanisms of the formation of adductor muscle coloration in the QN Orange Scallops, we compared the proteome and transcriptome of orange adductor muscles of the QN Orange and those of white adductor muscles of the Bohai Red Scallop, another strain selected from the interspecific hybrids of the bay Scallop and the Peruvian Scallop.

  • transcriptomic and proteomic analyses of genetic factors influencing adductor muscle coloration in qn orange Scallops
    BMC Genomics, 2019
    Co-Authors: Junlin Song, Chunde Wang
    Abstract:

    Color polymorphism, a high-valued trait, is frequently observed in molluscan shellfish. The QN Orange Scallop, a new Scallop strain successively selected from the interspecific hybrids of the bay Scallop (Argopecten irradians irradians) and the Peruvian Scallop (Argopecten purpuratus), is distinguished from other Scallops by its orange adductor muscles. In this study, to reveal the mechanisms of the formation of adductor muscle coloration in the QN Orange Scallops, we compared the proteome and transcriptome of orange adductor muscles of the QN Orange and those of white adductor muscles of the Bohai Red Scallop, another strain selected from the interspecific hybrids of the bay Scallop and the Peruvian Scallop. Transcriptomic analysis revealed 416 differentially expressed genes (DEGs) between white and orange adductor muscles, among which 216 were upregulated and 200 were downregulated. Seventy-four differentially expressed proteins (DEPs), including 36 upregulated and 38 downregulated proteins, were identified through label-free proteomics. Among the identified DEGs and DEPs, genes related to carotenoids biosynthesis including apolipophorin, and Cytochrome P450 and those related to melanin biosynthesis including tyrosinase and Ras-related protein Rab-11A were found to express at higher levels in orange adductor muscles. The high expression levels of VPS (vacuolar protein sorting) and TIF (translation initiation factor) in orange adductor muscle tissues indicated that carotenoid accumulation may be affected by proteins outside of the carotenoid pathway. Our results implied that the coloration of orange adductor muscles in the QN Orange Scallops may be controlled by genes modulating accumulation of carotenoids and melanins. This study may provide valuable information for understanding the mechanisms and pathways underlying adductor muscle coloration in molluscan shellfish.

  • Introduction of the Peruvian Scallop and its hybridization with the bay Scallop in China
    Aquaculture, 2010
    Co-Authors: Chunde Wang, Baozhong Liu, Shengping Liu, Xiao Fan, Huahua Fang
    Abstract:

    This study describes the first introduction of the Peruvian Scallop, Argopecten purpuratus (P), from Peru to China. Reciprocal hybridization was carried out between the newly introduced Peruvian Scallops and the bay Scallops. A. irradians irradians (I). Morphological and molecular evidence indicated that the derived offspring were true hybrids between the two Argopecten Scallops. At larval stages, when cultured at 23 degrees C, the growth rates of the hybrid cohorts were not different from that of the inbred bay Scallop group but significantly higher than that of the Peruvian Scallops. The survival rate of the A. purpuratus female x A. irradians male (P female x male) cohort was higher than those of both inbred cohorts but the A. irradians female x A. purpuratus male (I female x P male) cohort survived better than the bay Scallop cohort only. Significant maternal effects were noted on growth rate but not on survival rate. Mating strategy and its interaction with egg origin had significant effects on both growth and survival rates. During the adult grow-out stage, the survival rates of the hybrid cohorts were not different from that of the bay Scallops but were much higher than that of the Peruvian Scallops. The growth rates in both shell height and whole body weight in the hybrid cohorts were much higher than those of the inbred bay and Peruvian Scallop cohorts. Compared with the bay Scallops, the production traits in the hybrid cohorts were increased by 125.9-138.9% in whole body weight and by 145.4-156.2% in adductor muscle weight. Thus, although it may not be feasible to culture the Peruvian Scallops at a large scale in China, hybridizing the Peruvian Scallops with bay Scallops may be a very effective way in increasing Scallop production in China. (C) 2010 Elsevier B.V. All rights reserved.

Kevin D. E. Stokesbury - One of the best experts on this subject based on the ideXlab platform.

  • Fisheries Sea Scallop, Placopecten magellanicus
    Scallops - Biology Ecology Aquaculture and Fisheries, 2016
    Co-Authors: Kevin D. E. Stokesbury, Catherine E. O’keefe, Bradley P. Harris
    Abstract:

    Abstract The sea Scallop ( Placopecten magellanicus ) fisheries in the United States and Canada have experienced unprecedented rebuilding over the past 15 years. Several factors have led to the successful rebound of these industries, including revised management approaches, investments in improved survey technologies, data-rich stock assessments, favourable environmental conditions and some luck. There is no comprehensive understanding of the stock–recruitment relationship for Scallops, which complicates management of the species. Through the use of spatial and temporal management strategies, large recruitment events have been identified and juvenile Scallops can be protected until they reach a harvestable size. Identification and protection of such anomalous, large recruitment events in Canada and the United States over the past 15 years have rebuilt the stocks and sustained the fisheries. This chapter describes sea Scallop life history, the ecosystem inhabited by sea Scallops, the composition of the Canadian and US fishing fleets, sea Scallop stock assessments, resource surveys and sea Scallop fisheries management.

  • stock definition and recruitment implications for the u s sea Scallop placopecten magellanicus fishery from 2003 to 2011
    Reviews in Fisheries Science, 2012
    Co-Authors: Kevin D. E. Stokesbury
    Abstract:

    The United States sea Scallop management plan applies fishing mortality in a uniform manner, assigning a single value of instantaneous fishing mortality (F) to the entire resource. Applying a single value of fishing mortality assumes the Scallop resource is a single population. Dividing the resource into Georges Bank and Mid-Atlantic Bight reveals that each has been either excessively fished or underutilized based on the present definition of optimum yield. The sea Scallop resource was highest in 2003 and has declined by about 50,000 metric tons, entirely from the Mid-Atlantic Bight. Abundance and the corresponding harvest levels will likely continue if the resource is a single population and Scallops in the closed areas of Georges Bank populate the entire resource. Abundance and the corresponding harvest levels will likely decline if Georges Bank and the Mid-Atlantic Bight are separate populations in that Scallops within these areas have a closed lifecycle. The depletion of the large number of small scal...

  • high densities of juvenile sea Scallop placopecten magellanicus on banks and ledges in the central gulf of maine
    Journal of Shellfish Research, 2010
    Co-Authors: Kevin D. E. Stokesbury, Bradley P. Harris, Jonathan D Carey, Catherine E Okeefe
    Abstract:

    ABSTRACT A video survey was conducted from August 10–14, 2009, to estimate sea Scallop density, abundance, and size distribution on Platts Bank, Fippennies Ledge, Jeffreys Bank, Jeffreys Ledge, and Cashes Ledge in the central Gulf of Maine. Of the 298 km2 surveyed, 134 km2 (45%) had Scallops present. Scallop density was estimated using only stations containing at least 1 Scallop. High densities of small Scallops occurred on all but Jeffreys Bank, where no Scallops were observed. Densities ranged from 1.56 Scallops/m2 on Jeffreys Ledge to 4.70 Scallops/m2 on Platts Bank, equaling an estimated abundance of 470 million Scallops. Less than 1% of Scallops were larger than 100 mm. Explanations for the lack of large individuals may include sporadic recruitment, high natural mortality from predation, or environmental influences. If these Scallops were to survive to harvestable size (approximately 102 mm), they could provide an important commercial resource worth approximately USS124 million.

  • spatial and temporal variation in the shell height meat weight relationship of the sea Scallop placopecten magellanicus in the georges bank fishery
    Journal of Shellfish Research, 2009
    Co-Authors: Christopher L Sarro, Kevin D. E. Stokesbury
    Abstract:

    ABSTRACT Spatial and temporal variations in the meat weight of sea Scallops were examined in the Georges Bank fishery. From 1998–2007, 31 commercial Scallop vessels supplied 145 dissections from the last tow of their fishing trip. During the dissection process we recorded the shell height, meat weight, sex, gonad weight, and visceral tissue weight. Meat weight was regressed against shell height (Ln(MW) = α + β ln SH). Predicted meat weight varied by up to 29% for a 120 mm shell height Scallop among months. Scallop meat weight varied by 31% for a 120 mm shell height Scallop between areas in the same month. The Southern Flank of Georges Bank had a different pattern of monthly variation in meat weight, possibly because of a spring spawning event observed in the gonadal indices. These spatial and temporal differences in meat weight could affect harvest, and harvest rate, with a 22% difference in Scallops harvested between June and October calculated from a hypothetical fishery. Understanding these spatial and...

  • spatio temporal variations of sea star asterias spp distributions between sea Scallop placopecten magellanicus beds on georges bank
    Marine Ecology Progress Series, 2009
    Co-Authors: Michael C Marino, Francis Juanes, Kevin D. E. Stokesbury
    Abstract:

    Presently 80% of the biomass of sea Scallop Placopecten magellanicus on Georges Bank is located within 3 large areas closed to fisheries. Sea stars Asterias spp., primary predators of scal- lops, are also aggregated within these closed areas. As prey becomes depleted within one Scallop bed, sea stars may move to another food source, possibly to another Scallop bed. We tested the hypothesis that sea star aggregations moved from one Scallop bed to another within the Nantucket Lightship Closed Area (NLCA) on Georges Bank. We video surveyed 204 stations in the NLCA from 1999 to 2006 using a 1.57 km grid-centric systematic sampling design. The center of sea star abun- dance was calculated by averaging the sea star frequency-weighted latitude and longitude for all stations. Using multivariate analysis of variance and all-pairs comparisons (Hotelling's T 2 ), shifts in the center of sea star abundance were determined by assessing if the locations of the 2 aggregations were different. The sea star center of abundance, standard ellipse and 95% confidence ellipse were superimposed on the Scallop density distribution maps to determine the spatial overlap. The distrib- utions of sea star aggregations in the NLCA significantly shifted between consecutive years from 1999 to 2006 and overlapped with areas of high densities of Scallops. Shifts in the center of abundance reflect changes in distribution possibly resulting from movement, recruitment and mortality. As sea stars aggregate in these areas presumably due to high abundances of Scallops, sea star movement between the Scallop beds may increase natural mortality rates of the Scallop population on Georges Bank.

A R Brand - One of the best experts on this subject based on the ideXlab platform.

  • Benefits of closed area protection for a population of Scallops
    Marine Ecology Progress Series, 2005
    Co-Authors: B. D. Beukers-stewart, Matthew W J Mosley, Belinda J. Vause, Helen L. Rossetti, A R Brand
    Abstract:

    Despite the current interest in using closed areas for fisheries management, few studies have actually examined the benefits for invertebrate fisheries such as Scallops. This study details the dynamics of a population of great Scallops Pecten maximus (L.), within a closed area and an adjacent fished area off the Isle of Man, over a 14 yr period (1989 to 2003). Scallop densities were very low in both areas when the closed area was set up, but increased at an accelerated rate over time within the closed area. Scallop densities also increased on the adjacent fishing ground, but not to the same extent. Consequently, the density of Scallops above the minimum legal landing size (110 mm SL) was more than 7 times higher in the closed area than in the fished area by 2003. There was also a shift towards much older and larger Scallops in the closed area and, correspondingly, lower estimates of total mortality. Experimental dredging of 2 plots within the closed area confirmed that fishing drove these differences in population dynamics and structure. These patterns of Scallop density, age and size structure resulted in the exploitable biomass (adductor muscle and gonad) of Scallops being nearly 11 times higher in the closed area than in the fished area by 2003, and the reproductive biomass was 12.5 times higher. This is significant for fisheries management because the build up of high densities of large P. maximus individuals enhanced local reproductive potential and therefore the likelihood of export of larvae to the surrounding fishing grounds. Along with these direct benefits of closed area protection, juvenile Scallops had higher survival and individual growth rates in the closed area, apparently in response to reduced fishing disturbance. Although juvenile Scallops are not subject to direct removal by fishing, protection during this critical phase therefore appeared to assist the recovery of the closed area population. In summary, this study joins a growing number indicating that the use of closed areas offers a range of benefits over more traditional methods of managing fisheries. Fisheries for relatively sedentary and long-lived species such as P. maximus appear to be particularly suitable for this type of management.

  • Biological control of fouling in suspended Scallop cultivation.
    Aquaculture, 2003
    Co-Authors: Katherine A. Ross, John P. Thorpe, A R Brand
    Abstract:

    Abstract Fouling of Scallop shells and cultivation nets by living organisms is costly to remove and can reduce Scallop growth. Here we investigate biological control of fouling in suspended Scallop ( Pecten maximus ) cultivation. In preliminary trials in the Irish Sea, off the Isle of Man, sea urchins ( Echinus esculentus and Psammechinus miliaris ) and hermit crabs ( Pagurus spp.) removed fouling from nets more efficiently than did a range of other invertebrates. Sea urchins and hermit crabs were subsequently deployed from August 2000 to January 2001 at various densities (hermit crabs and E. esculentus at 1, 2, or 3 per net and P. miliaris at 3, 5 or 7 per net) in pearl nets containing Scallops. After 6 months, the survival of biological control organisms and their effect on Scallop growth and mortality, and fouling of nets and Scallop shells, were assessed. Only P. miliaris was associated with increased Scallop shell growth, but no biological control organism reduced Scallop growth or survival. All three biological control organisms significantly reduced the weight of fouling on nets (often by as much as 50%) and fouling of Scallop shells; results were largely independent of biological control organism density. Sea urchins were most effective, removing hydroids and solitary tunicates efficiently; they could thus be commercially exploited alongside Scallops in a form of polyculture. These results suggest that biological control could be an efficient and environmentally sound method of addressing the problem of fouling in Scallop cultivation.

  • population dynamics and predictions in the isle of man fishery for the great Scallop pecten maximus l
    Ices Journal of Marine Science, 2003
    Co-Authors: B D Beukersstewart, Matthew W J Mosley, A R Brand
    Abstract:

    There has been a fishery for the great Scallop, Pecten maximus, around the Isle of Man, since 1937. Research up to the end of the 1980s suggested that these Scallop stocks were in continuous decline. The fishery is now largely dependent on the strength of each recruiting year-class, placing it at considerable risk from recruitment failure. This study utilised data on the spat settlement, age structure, abundance and commercial catch rates of Scallops, collected between 1975 and 2001, to examine recent population dynamics and the potential for predicting future catch rates. Spat settlement was generally low, but there were two exceptionally strong year-classes. Surveys of the stock revealed high exploitation rates during each fishing season (November to May inclusive) with variable recovery due to recruitment by the following October. In 1997/1998, Scallop catch rates reached a 20-year high on several grounds and have generally remained high since. The strong spat settlements in 1989 and particularly 1994 were largely responsible for recent rises in catch rates, although the maintenance of high catch rates between 1999 and 2001 has occurred despite poor spat settlement between 1995 and 2000. Within stock surveys, the density of 2-year-old Scallops was generally an accurate predictor of the density of 3- and 4-year-old Scallops, 1-2 years later. The nature and strength of these relationships varied considerably between fishing grounds due to spatial variation in both Scallop biology and patterns of exploitation. Results from fishery independent surveys did not always correlate well with commercial catch rates, however, suggesting the need for an expansion of the survey on some grounds. Overall, our study indicated that current levels of exploitation appear to be sustainable in the Isle of Man Scallop fishery. Our results also demonstrated that monitoring of both spat settlement and the abundance of juveniles has considerable potential for predicting future catch rates of commercial sized Scallops.

  • the effect of dredge capture on the escape response of the great Scallop pecten maximus l implications for the survival of undersized discards
    Journal of Experimental Marine Biology and Ecology, 2001
    Co-Authors: Stuart R. Jenkins, A R Brand
    Abstract:

    The effect of simulated dredge capture on the swimming escape response of the great Scallop, Pecten maximus, was assessed in order to determine the potential for mortality in undersized discards. Three experiments were carried out: firstly, to determine how the effect of simulated dredging on the escape response varied with season and Scallop size; secondly, to assess the time taken for Scallops to recover following simulated dredging; and thirdly, to determine the interactive effects of dredging, exposure to air and recovery time. In all experiments, simulated dredging caused a significant increase in the response time of Scallops and a significant decrease in the number of valve adductions performed. The negative effects of dredging occurred irrespective of season (spring versus autumn) and Scallop size. Exposure to air also had a negative effect on the escape response, which was evident in both dredged and nondredged Scallops. Determination of the period taken to recover showed that although some recovery was evident after 1 h, the negative effects of simulated dredge capture were still apparent after a period of 24 h. These results suggest that there is a potential for high levels of mortality in undersized discarded Scallops, and Scallops which encounter dredges but are not captured.

Junlin Song - One of the best experts on this subject based on the ideXlab platform.

  • transcriptomic and proteomic analyses of genetic factors influencing adductor muscle coloration in qn orange Scallops
    BMC Genomics, 2019
    Co-Authors: Junlin Song, Chunde Wang
    Abstract:

    Background Color polymorphism, a high-valued trait, is frequently observed in molluscan shellfish. The QN Orange Scallop, a new Scallop strain successively selected from the interspecific hybrids of the bay Scallop (Argopecten irradians irradians) and the Peruvian Scallop (Argopecten purpuratus), is distinguished from other Scallops by its orange adductor muscles. In this study, to reveal the mechanisms of the formation of adductor muscle coloration in the QN Orange Scallops, we compared the proteome and transcriptome of orange adductor muscles of the QN Orange and those of white adductor muscles of the Bohai Red Scallop, another strain selected from the interspecific hybrids of the bay Scallop and the Peruvian Scallop.

  • transcriptomic and proteomic analyses of genetic factors influencing adductor muscle coloration in qn orange Scallops
    BMC Genomics, 2019
    Co-Authors: Junlin Song, Chunde Wang
    Abstract:

    Color polymorphism, a high-valued trait, is frequently observed in molluscan shellfish. The QN Orange Scallop, a new Scallop strain successively selected from the interspecific hybrids of the bay Scallop (Argopecten irradians irradians) and the Peruvian Scallop (Argopecten purpuratus), is distinguished from other Scallops by its orange adductor muscles. In this study, to reveal the mechanisms of the formation of adductor muscle coloration in the QN Orange Scallops, we compared the proteome and transcriptome of orange adductor muscles of the QN Orange and those of white adductor muscles of the Bohai Red Scallop, another strain selected from the interspecific hybrids of the bay Scallop and the Peruvian Scallop. Transcriptomic analysis revealed 416 differentially expressed genes (DEGs) between white and orange adductor muscles, among which 216 were upregulated and 200 were downregulated. Seventy-four differentially expressed proteins (DEPs), including 36 upregulated and 38 downregulated proteins, were identified through label-free proteomics. Among the identified DEGs and DEPs, genes related to carotenoids biosynthesis including apolipophorin, and Cytochrome P450 and those related to melanin biosynthesis including tyrosinase and Ras-related protein Rab-11A were found to express at higher levels in orange adductor muscles. The high expression levels of VPS (vacuolar protein sorting) and TIF (translation initiation factor) in orange adductor muscle tissues indicated that carotenoid accumulation may be affected by proteins outside of the carotenoid pathway. Our results implied that the coloration of orange adductor muscles in the QN Orange Scallops may be controlled by genes modulating accumulation of carotenoids and melanins. This study may provide valuable information for understanding the mechanisms and pathways underlying adductor muscle coloration in molluscan shellfish.

Myriam A Barbeau - One of the best experts on this subject based on the ideXlab platform.

  • behavioural mechanisms of sea stars asterias vulgaris verrill and leptasterias polaris muller and crabs cancer irroratus say and hyas araneus linnaeus preying on juvenile sea Scallops placopecten magellanicus gmelin and procedural effects of Scallop
    Journal of Experimental Marine Biology and Ecology, 2009
    Co-Authors: Madeleine Nadeau, Myriam A Barbeau, Jeanclaude Brethes
    Abstract:

    Abstract We compared predation rates and behaviours of sea stars ( Asterias vulgaris and Leptasterias polaris ) and crabs ( Cancer irroratus and Hyas araneus ) preying on juvenile sea Scallops ( Placopecten magellanicus , 25-35 mm shell height) in laboratory. These predatory species co-occur with sea Scallops on the sea bed of the Gulf of St. Lawrence, Canada, and limit Scallop survival in seeding operations. We also examined, under controlled conditions, the effect of tethering Scallops on predator–prey interactions. Predation rates, time budgets and encounter behaviours observed for A. vulgaris and C. irroratus preying on free (untethered) Scallops were comparable to previous studies. C. irroratus were more effective predators as they consumed 3.1 Scallops predator − 1 day − 1 , although they spent only 0.9% of their time searching for prey. A. vulgaris consumed 0.9 Scallops predator − 1 day − 1 and spent 7.6% of their time searching. Sea stars L. polaris had a lower predation rate (0.02 Scallop predator − 1 day − 1 ) than A. vulgaris . The frequent avoidance behaviour of L. polaris and its low ability to capture Scallops support the notion that Scallops are not a main component of this sea star's diet. Crabs H. araneus had similar predation rates (1.3 Scallops predator − 1 day − 1 ) and behaviours to C. irroratus , although the probability of consumption upon capture was affected by relatively high numbers of rejections and post-capture escapes of Scallops. As expected, the tethering procedure increased predation rate of L. polaris (about 19 times higher), but surprisingly did not significantly affect that of A. vulgaris . Examination of behaviours indicated that A. vulgaris offered tethered Scallops tended to have a higher probability of capture, but spent less time searching for prey (possibly because satiation was reached) than A. vulgaris offered free Scallops. Predation rates and behaviours of both crab species were not affected by tethering, since encounter rate was the primary determinant of crab-Scallop interactions. Identification and quantification of behaviours underlying the predation process allowed us to mathematically model predator-related mortality for the four predator species.

  • sediment selection by juvenile sea Scallops placopecten magellanicus gmelin sea stars asterias vulgaris verrill and rock crabs cancer irroratus say
    Journal of Shellfish Research, 2006
    Co-Authors: Melisa C Wong, Lisa D Wright, Myriam A Barbeau
    Abstract:

    Abstract We examined sediment selection by juvenile sea Scallops (Placopecten magellanicus) and their predators, sea stars (Asterias vulgaris) and rock crabs (Cancer irroratus). In laboratory trials, groups of Scallops (~30 mm shell height) were simultaneously offered four sediment types in the presence and absence of a sea star or a rock crab: (1) glass representing a homogeneous, hard bottom; (2) sand; (3) granule and (4) pebble. As well, individual predators were offered the four sediment types without Scallops. The number of Scallops and the proportion of time predators spent on each sediment type were monitored over time. When compared with the expected distribution, Scallops avoided glass and tended to select granule and pebble sediments when alone. In the presence of a rock crab, Scallops also avoided glass. However, Scallop distribution was similar to the expected distribution when a sea star was present, because sea star encounters are an important trigger of Scallop swimming, leading to frequent...

  • prey selection and the functional response of sea stars asterias vulgaris verrill and rock crabs cancer irroratus say preying on juvenile sea Scallops placopecten magellanicus gmelin and blue mussels mytilus edulis linnaeus
    Journal of Experimental Marine Biology and Ecology, 2005
    Co-Authors: Melisa C Wong, Myriam A Barbeau
    Abstract:

    Abstract Predators in nature include an array of prey types in their diet, and often select certain types over others. We examined (i) prey selection by sea stars ( Asterias vulgaris ) and rock crabs ( Cancer irroratus ) when offered two prey types, juvenile sea Scallops ( Placopecten magellanicus ) and blue mussels ( Mytilus edulis ), and (ii) the effect of prey density on predation, prey selection, and component behaviours. We quantified predation rates, behavioural components (proportion of time spent searching for prey, encounter probabilities) and various prey characteristics (shell strength, energy content per prey, handling time per prey) to identify mechanisms underlying predation patterns and to assess the contribution of active and passive prey selection to observed selection of prey. Sea stars strongly selected mussels over Scallops, resulting from both active and passive selection. Active selection was associated with the probability of attack upon encounter; it was higher on mussels than on Scallops. The probability of capture upon attack, associated with passive selection, was higher for mussels than for Scallops, since mussels can not swim to escape predators. Sea stars consumed few Scallops when mussels were present, and so did not have a functional response on Scallops (the target prey). Rock crabs exhibited prey switching: they selected mussels when Scallop density was very low, did not select a certain prey type when Scallop density was intermediate, and selected Scallops when Scallop density was high relative to mussel density. The interplay between encounter rate (associated with passive selection) and probability of consumption upon capture (associated with both active and passive selection) explained observed selection by crabs. Scallops were encountered by crabs relatively more often and/or mussels less often than expected from random movements of animals at all Scallop densities. However, the probability of consumption varied with Scallop density: it was lower for Scallops than mussels at low and intermediate Scallop densities, but tended to be higher for Scallops than mussels at high Scallop densities. When mussels were absent, crabs did not have a functional response on Scallops, but rather were at the plateau of the response. When mussels were present with Scallops at relatively low density, crabs exhibited a type II functional response on Scallops. Our results have implications for the provision of protective refuges for species of interest (i.e., Scallops) released onto the sea bed, such as in population enhancement operations and bottom aquaculture.

  • effects of substrate on interactions between juvenile sea Scallops placopecten magellanicus gmelin and predatory sea stars asterias vulgaris verrill and rock crabs cancer irroratus say
    Journal of Experimental Marine Biology and Ecology, 2003
    Co-Authors: Melisa C Wong, Myriam A Barbeau
    Abstract:

    Abstract We investigated the effect of substrate (glass bottom, sand, granule, pebble) on predation of juvenile sea Scallops ( Placopecten magellanicus ) by sea stars ( Asterias vulgaris ) and rock crabs ( Cancer irroratus ) at two prey sizes (11–15 mm and 24–28 mm shell height), and two prey densities (10 and 30 Scallops per aquarium) in laboratory experiments. Specifically, we quantified predation rate and underlying behaviours (proportion of time a predator spent searching for and handling prey, encounter rate between predators and prey, and various outcomes of encounters). We detected a significant gradual effect of particle size of natural substrates on sea star predation: specifically, predation rate on and encounter rate with small Scallops tended to decrease with increasing particle size (being highest for sand, intermediate for granule, and lowest for pebble). Substrate type did not significantly affect predation rates or behaviours of sea stars preying on large Scallops or of rock crabs preying on either Scallop size classes. Other factors, such as prey size and density, were important in the Scallop-sea star and Scallop-rock crab systems. For example, predation rate by sea stars and crabs and certain sea star behaviours (e.g. probability of consuming Scallops upon capture) were significantly higher with small Scallops than with large Scallops. As well, in interactions between small Scallops and sea stars, predation rate and encounter rate increased with prey density, and the proportion of time sea stars spent searching was higher at low prey density than high prey density. Thus, substrate type may be a minor factor determining predation risk of seeded Scallops during enhancement operations; prey size and prey density may play a more important role. However, substrate type still needs to be considered when choosing a site for Scallop enhancement, as it may affect other Scallop behaviours (such as movement).

  • predator prey interactions between juvenile sea Scallops placopecten magellanicus and predatory sea stars asterias spp and crabs cancer irroratus
    1994
    Co-Authors: Myriam A Barbeau
    Abstract:

    This study examines the effects of biological and physical factors on predation of juvenile sea Scallops (Placopecten magellanicus; 5-28 mm shell height) by two major predators, sea stars (Asterias spp.) and crabs (Cancer irroratus). Predator-prey size laboratory experiments with sea stars (30-150 mm diameter) showed that predation rates increased with increasing sea star size and decreasing Scallop size. Preference for small Scallops by sea stars was determined by prey vulnerability resulting from differential probabilities of capture upon encounter, even though the probability of capture was $$0.20, since Scallops often closed their valves upon encounter with crabs. In laboratory experiments, predation rates on preferred prey sizes increased with water temperature (3-15$\sp\circ$C) with Q$\sb $ values of 6.9 and 2.1 for sea stars and crabs, respectively. The increase in predation rate with temperature was attributable to increased foraging activity of sea stars and crabs, and decreased escape effectiveness of Scallops with sea stars. In a field experiment manipulating Scallop density, crab predation rate increased with Scallop density, but crab density did not, indicating a functional response. Sea star predation rate on Scallops was not affected by Scallop density. In a series of experiments with different size classes of Scallops tethered at different sites and water temperatures (seasons), and in different densities of predators and free-living Scallops, the effects of covariates on Scallop survival times were assessed using the statistical procedure of survival analysis. Since the tethering technique affected crab and sea star predation differently, the competing causes of Scallop mortality were analysed separately. Water temperature, site, and Scallop density were the important variables affecting crab predation. There was a significant interaction between temperature and site, such that crab predation on Scallops increased with temperature at one site and was independent of temperature at the other site. Predation by crabs also increased with Scallop density and, to a lesser extent, with crab density. Water temperature and Scallop size were the primary variables affecting sea star predation. Sea star predation on Scallops increased with temperature and decreased with Scallop size. The results of this study further our understanding of predator-prey interactions in the marine benthic environment as well as suggest options for minimizing predation of Scallops by crabs and sea stars in bottom culture operations.