Release Strategies in Scallop (
            <i>Pecten maximus</i>
            ) Sea Ranching Vulnerable to Crab Predation

Strand, Øivind; Grefsrud, Ellen Sofie; Haugum, Geir Askvik; Bakke, Gunnar; Helland, E.; Helland, T. E.

doi:10.1002/9780470751329.ch40

Cited by 7 publications

(4 citation statements)

References 13 publications

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“…In the present study, there was a significant positive correlation between percentage recapture and size-at-release. In a range of marine invertebrate species, it has been demonstrated that larger size-at-release usually results in higher survival postrelease (Liu 1990;Strand et al 2004;Bell et al 2005;Ye et al 2005). However, optimisation of size-at-release for the Scylla spp.…”

Section: Recaptures and Release Strategiesmentioning

confidence: 99%

Evaluation of hatchery-based enhancement of the mud crab, Scylla spp., fisheries in mangroves: comparison of species and release strategies

Lebata

Vay

Walton

et al. 2009

Mar. Freshwater Res.

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Ranching, stock enhancement and restocking are management approaches involving the release of wild or hatchery-bred organisms to enhance, conserve or restore fisheries. The present study, conducted from April 2002 to November 2005, evaluated the effectiveness of releasing wild and hatchery-reared (HR) mud crabs in the mangroves of Ibajay, Aklan, Philippines where preliminary studies demonstrated declining fishery yields, abundance and size of crabs. Comparison of survival and growth of wild-released and HR Scylla olivacea and HR Scylla serrata demonstrated the effect of nursery conditioning, size-at-release and species differences. Overall yield and catch per unit effort (CPUE) increased by 46% after stock enhancement trials. Recapture rates of released crabs were highest in wild-released S. olivacea and in crabs measuring 65.0-69.9 mm carapace width (CW) and lowest in non-conditioned HR S. serrata. Growth rates were highest for conditioned HR S. olivacea and lowest for conditioned HR S. serrata (11.7 and 3.7 mm month −1 respectively). Fishing mortality was highest for S. olivacea, whereas natural mortality was greater for S. serrata. Conditioning hatcherybred animals before release is also important in obtaining higher survival. S. olivacea was the more appropriate of the two species for release in mangrove habitats inundated with low-salinity water. However, there is a need for site-specific studies to evaluate the effectiveness of releases.

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Section: Recaptures and Release Strategiesmentioning

confidence: 99%

Evaluation of hatchery-based enhancement of the mud crab, Scylla spp., fisheries in mangroves: comparison of species and release strategies

Lebata

Vay

Walton

et al. 2009

Mar. Freshwater Res.

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“…However, naïve, inexperienced individuals raised under laboratory or controlled conditions often demonstrate aberrant behaviours, such as reduced antipredator behaviour and foraging in the wild [ 7 – 9 ]. Release experiments have shown that hatchery produced juveniles are more prone to predation when released in the wild [ 10 – 12 ], thus the main challenge is to increase survival rates after release.…”

Section: Introductionmentioning

confidence: 99%

An Enriched Environment Promotes Shelter-Seeking Behaviour and Survival of Hatchery-Produced Juvenile European Lobster (Homarus gammarus)

et al. 2016

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The high loss of newly released hatchery-reared European lobster (Homarus gammarus) juveniles for stock enhancement is believed to be the result of maladaptive anti-predator behaviour connected to deprived stimuli in the hatchery environment. Our objective was to learn if an enriched hatchery environment enhances shelter-seeking behaviour and survival. In the “naïve” treatment, the juveniles were raised in single compartments without substrate and shelter whereas juveniles in the “exposed” treatment experienced substrate, shelter and interactions with conspecifics. Three experiments with increasing complexity were conducted. Few differences in shelter-seeking behaviour were found between treatments when one naïve or one exposed juvenile were observed alone. When observing interactions between one naïve and one exposed juvenile competing for shelter, naïve juveniles more often initiated the first aggressive encounter. The third experiment was set up to simulate a release for stock enhancement. Naïve and exposed juveniles were introduced to a semi-natural environment including substrate, a limited number of shelters and interactions with conspecifics. Shelter occupancy was recorded three times during a period of 35 days. Exposed juveniles occupied more shelters, grew larger and had higher survival compared with naïve juveniles. Our results demonstrate that experience of environmental complexity and social interactions increase shelter-seeking ability and survival in hatchery reared lobster juveniles.

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“…Thus, the rate of survival of seeded scallops, termed the survival rate, is determined by the level of losses from dispersion and predation during the sea ranching phase. Sea stars and crabs are generally thought to have the largest predatory impact on seeded scallops of a variety of species (Barbeau and Scheibling 1994a; Barbeau and Scheibling 1994b;Cliche et al 1994; Barbeau et al 1996;Hatcher et al 1996; Barbeau et al 1998;Strand et al 2002;Grefsrud et al 2003;Barbeau 2003, 2005;, although fish also may reduce numbers of smaller scallops (Strohmeier et al 2006). Trials have shown that fencing areas of the seabed can limit the access of crabs to seeded scallops (Strand et al 2004); however, methodologies commonly used to exclude crabs do not exclude sea stars.…”

Section: Introductionmentioning

confidence: 99%

“…During sea ranching, fences have been shown to reduce predation by brown crabs resulting in increased P. maximus survival from \5 to 89% (Strand et al 2004). Although both crabs (Grefsrud et al 2003;Strand et al 2004) and fish (Strohmeier et al 2006) have been identified as potential predators on P. maximus in Norway, there is no known study of the impact of sea stars. The sea stars Asterias rubens and Marthasterias glacialis are important bivalve predators in shallow water ecosystems in western Norway (Wiborg 1946).…”

Section: Introductionmentioning

confidence: 99%

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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Release Strategies in Scallop ( Pecten maximus ) Sea Ranching Vulnerable to Crab Predation

Cited by 7 publications

References 13 publications

Evaluation of hatchery-based enhancement of the mud crab, Scylla spp., fisheries in mangroves: comparison of species and release strategies

Evaluation of hatchery-based enhancement of the mud crab, Scylla spp., fisheries in mangroves: comparison of species and release strategies

An Enriched Environment Promotes Shelter-Seeking Behaviour and Survival of Hatchery-Produced Juvenile European Lobster (Homarus gammarus)

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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