Long-term Changes in Intra- and Inter-specific Relationships in a Community of Scallops and Sea Stars under Bottom Scallop Mariculture

Silina, Alla V.

doi:10.2983/0730-8000-27.5.1189

Cited by 10 publications

(13 citation statements)

References 6 publications

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“…While we did not observe a massive influx of predators after scallop planting in late March/early April, as has been observed by some authors following scallop plantings (e.g. Volkov et al 1983;Silina 2008), it is very likely that predation was the primary factor responsible for mortality of free-planted scallops throughout the study. This conclusion is supported by the fact that increases in predator densities from early April to early May of both years coincided with significant declines in scallop density over the same periods.…”

Section: High-density Free-plantmentioning

confidence: 46%

“…Transplantation of wild juveniles or adults has also been done for scallop aquaculture in Russia (Ivin et al 2006) and for restoration in the US (Peterson et al 1996). Plantings of juvenile scallops for put-and-take fisheries have often been done at relatively low densities (B10/m 2 ) in order to avoid attracting high numbers of predators and/or because of concerns over growth inhibition (Kosaka and Ito 2006;Silina 2008). The utility of this approach has been confirmed by studies of scallop predation at a range of densities, where higher rates of predation typically have been observed at higher free-planting densities (Morgan et al 1980;Tettelbach 1986;Silina 1994; Barbeau et al 1996;Wong et al 2005;Félix-Pico 2006); these same studies also concluded that mortality of free-planted scallops is inversely related to scallop size.…”

Section: Introductionmentioning

confidence: 98%

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Utility of high-density plantings in bay scallop, Argopecten irradians irradians, restoration

Tettelbach

Barnes

Aldred³

et al. 2010

Aquacult Int

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Two different methods of establishing high-density spawner sanctuaries for bay scallop (Argopecten irradians irradians) restoration were evaluated over 2 years at a site in Northwest Harbor, East Hampton, New York, USA. Hatchery-reared scallops, which had been overwintered at nearby sites, were free-planted directly to the bottom in late March/ early April at an initial target density of 94-128 scallops/m 2 . In addition, scallops were stocked in off-bottom culture units consisting of three vertically stacked 15-mm mesh ADPI Ò bags at densities of 50, 100, or 200 scallops/bag (=117, 234, or 468 scallops/m 2 ), respectively. Survival of scallops differed significantly by year, planting method, and scallop source. Survival of free-planted scallops was generally lower than caged scallops. Better survival of free-planted scallops in 2005 versus 2006 likely reflected the presence of luxuriant eelgrass beds in 2005, which were absent in 2006. Survival of scallops in ADPI bags was not appreciably related to stocking density. Shell growth was highest for freeplanted scallops; in cages, growth was somewhat better at 50 versus 200 scallops/bag. Wet weights of epibionts were significantly higher in caged versus free-planted scallops. Reproductive condition of scallops stocked at 50/bag was usually higher than at 200/bag. Both free-planting and off-bottom systems yielded high densities of adult bay scallops at the time of spawning, which ensures a higher probability of successful fertilization of spawned eggs and thus a greater potential for success of restoration efforts.

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Section: High-density Free-plantmentioning

confidence: 46%

Section: Introductionmentioning

confidence: 98%

Utility of high-density plantings in bay scallop, Argopecten irradians irradians, restoration

Tettelbach

Barnes

Aldred³

et al. 2010

Aquacult Int

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“…Intraspecific competition can reduce growth at high densities (e.g. Marsden 2002, Silina 2008 or reduce growth rates for small individuals forced to compete with larger ones (e.g. Kautsky 1982).…”

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confidence: 99%

Small macrobenthic invertebrates affect the mortality and growth of early post-settlement sea urchins and sea stars in subtidal cobble habitat

Jennings

Hunt²

2011

Mar. Ecol. Prog. Ser.

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Early post-settlement events can have a large impact on the successful recruitment of benthic invertebrates. A field caging experiment was conducted in 2007 to examine whether predation by, and/or competition with, small macrofauna affects mortality or growth of recently settled sea urchins Strongylocentrotus droebachiensis or sea stars Asterias spp. Kelp was added to half of the sea urchin cages to test whether the addition of this food source (including its associated biofilms) altered growth or survival. Sea urchins survived 25% better in cages where the other organisms were removed, indicating that predation or bulldozing likely plays an important role. The growth of sea urchins was greatest in cages without other organisms and lowest in cages with other organisms and with food, possibly indicating competition that affects sea urchin behaviour. Sea stars showed the opposite trend in survival. A greater proportion of sea stars survived in cages where the other organisms were present (31.3 vs. 11.5%), presumably due to them being a food source for the sea stars, indicating that starvation, cannibalism and/or competition for food are likely important for recent settlers of this taxon. The declines in abundance in the cages were greater than those in the natural environment for sea urchins, but similar for sea stars, suggesting that caution is required when extrapolating experimental results to the field. These results indicate that multiple factors, which differ between these species, affect early post-settlement growth and mortality. KEY WORDS: Strongylocentrotus droebachiensis · Asterias spp. · Mortality · Growth · Predation · Competition · Early post-settlement · Natural declinesResale or republication not permitted without written consent of the publisher 90% mortality in juvenile limpets due to interspecific competition, an amount comparable to predation.However, competition does not have to be fatal, and may be more likely to have sublethal impacts on processes such as growth or fecundity (Birch 1957, Tomas et al. 2005. Intraspecific competition can reduce growth at high densities (e.g. Marsden 2002, Silina 2008 or reduce growth rates for small individuals forced to compete with larger ones (e.g. Kautsky 1982). Reduced growth rates can prolong the time it takes to reach recruitment (if defined by size) and sexual maturity.When predation and competition are examined together, the presence of predators often results in a greater reduction in abundance, fecundity and growth than does the presence of competitors (e.g. Aukema & Raffa 2002, Beal 2006. However, few studies have examined the effects of both predation and competition on juveniles. In the sea urchin Evechinus chloroticus, juveniles had higher densities when predators were excluded, regardless of the presence of adult conspecifics (Andrew & Choat 1982). Beal (2006) found that, while both predation and intraspecific competition had significant impacts on the survival of juvenile clams Mya arenaria, predation accounted for 45% of the variabi...

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“…Increased predation rates at higher densities may reflect improved capture probability (Barbeau et al 1998;, and the presence of conspecifics is thought to stimulate feeding through chemosensory signals and contact (Gaymer et al 2002). Sea star populations have been shown to increase following introduction of scallops for sea ranching (Cliche et al 1994;Barbeau et al 1996;Hatcher et al 1996;Barbeau et al 1998;Silina 2008), and furthermore, aggregations of sea stars have been shown to move between years, and these changes have overlapped with areas of high scallop densities (Marino et al 2009). The current study indicated that a population of seeded scallops could be reduced by 0.5-11% per month.…”

Section: Discussionmentioning

confidence: 95%

Potential predation rates by the sea stars Asterias rubens and Marthasterias glacialis, on juvenile scallops, Pecten maximus, ready for sea ranching

Magnesen

Redmond

2011

Aquacult Int

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The potential for predation by the sea stars Asterias rubens and Marthasterias glacialis on seed-size (41 ± 3 mm shell height) juvenile scallops (Pecten maximus), ready for seeding in sea ranching areas, was investigated in a 30-day laboratory predation experiment. There was no significant difference (P [ 0.05) in predation rate of large A. rubens (95-115 mm radium) and large M. glacialis (120-164 mm radius), which averaged 0.88 and 0.71 scallops individual -1 day -1 , respectively. Maximum rates of predation were 2.44 scallops individual -1 day -1 for large A. rubens and 3.00 scallops individual -1 day -1 for large M. glacialis. Small M. glacialis (76-87 mm radius) had a significantly lower predation rate than large individuals of either species (average 0.13 scallops individual -1 day -1 , P \ 0.05). Small A. rubens (50-80 mm radius) only began to prey on scallops when average scallop size was reduced to 35 mm. Based on estimated density of sea stars at a Norwegian sea ranching site and average predation rates, a population of scallops seeded at 10 m -2 would be reduced by between 0.5 and 11% in 1 month. Furthermore, using the highest observed predation rate, the degree of loss of scallops indicated that scallop culture via sea ranching would not be economically viable and thus methods for reducing scallop predation by sea stars are necessary.

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Long-term Changes in Intra- and Inter-specific Relationships in a Community of Scallops and Sea Stars under Bottom Scallop Mariculture

Cited by 10 publications

References 6 publications

Utility of high-density plantings in bay scallop, Argopecten irradians irradians, restoration

Utility of high-density plantings in bay scallop, Argopecten irradians irradians, restoration

Small macrobenthic invertebrates affect the mortality and growth of early post-settlement sea urchins and sea stars in subtidal cobble habitat

Potential predation rates by the sea stars Asterias rubens and Marthasterias glacialis, on juvenile scallops, Pecten maximus, ready for sea ranching

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