Sea scallop larvae Placopecten magellanicus on Georges Bank: vertical distribution in relation to water column stratification and food

Tremblay, M. John; Sinclair, Michael

doi:10.3354/meps061001

Cited by 72 publications

(45 citation statements)

References 31 publications

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“…Approximately 540000 D-stage larvae were introduced into each replicate 9.5 m deep tube in the Tower Tank, giving a final larval concentration in each tube of -0.20 larvae ml-l. This concentration is somewhat lower than typical hatchery larval rearing densities of 1 to 5 larvae ml-l (Tremblay 1988), but at least 2 orders of magnitude greater than maximum densities found on Georges Bank [Tremblay & Sinclair (1990a) reported peaks in larval concentration within the water column as high as 0.002 larvae ml-'1. While experimental larval concentration was markedly greater than natural densities, it represents approximately the lowest concentration at which workable numbers of spat can be collected under such conditions.…”

Section: Methodsmentioning

confidence: 89%

“…Aggregation of larvae of Placopecten magellanicus at or above thermoclines/pycnoclines has been documented both in the field (Tremblay & Sinclair 1988, 1990a and in, laboratory mesocosms (Gallager et al 1996, Manuel et al 199613). In a previous study, found that settlement of giant scallop larvae-spawned from adults collected from Newfoundland, Canada-in 9 m deep thermally stratified mesocosms (i.e.…”

Section: Introductionmentioning

confidence: 99%

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Effect of thermoclines and turbulence on depth of larval settlement and spat recruitment of the giant scallop Placopecten magellanicus in 9.5 m deep laboratory mesocosms

Pearce¹,

Gallager²,

Manuel³

et al. 1998

Mar. Ecol. Prog. Ser.

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An experiment was conducted from December 1992 to February 1993 in a 10.5 m deep, 3.7 m diameter tank to examine the effect of thermoclines and water column turbulence on the depth of larval settlement and spat recruitment of the giant scallop Placopecten magellanicus (Gmelin) Polyethylene tube mesocosms set up within the tank were used to enclose 9.5 m deep columns of seawater which were then used as experimental replicates. Five different treatments were established as follows: (1) no turbulence and a l.S°C thermocline, (2) no turbulence and no thermal gradient, ( 3 ) low level of turbulence with a 1.5"C thermocline, (4) medium level of turbulence with a 0.5OC thermocline. and (5) high level of turbulence with no thermal gradient. Various turbulence levels simulated turbulent energies ranging from open oceanic environments to near-shore and coastal conditions with vertical dissipation rates ranging from 10-' to 1 0 -~ cm2 s -~. Ropes with collectors positioned at every 1 m depth interval were suspended the length of the water column in each replicate tube to collect settled spat. Spat counts varied significantly with both depth and turbulence treatment and were dependent on the interaction between the 2 factors. Numbers of spat generally increased with increasing depth in the static and low turbulence treatments, but this relationship became less evident with increasing turbulence; spat recruitment in the high turbulence tubes appeared random with respect to depth. It is suggested that the trend of increasing recruitment with depth in the static and low turbulence tubes was driven primarily by larval behaviour at settlement. There was no indication of increased recruitment at or above the thermocline, in contrast to a prevlous mesocosm experiment with a stronger thermal gradient and a different population of larvae, suggesting that strahfication intensity may affect depth of larval settlement and spat recruitment. Settlement rate did not appear to be a strict function of larval encounter rate with the spat collectors. Higher spat counts in treatments with a 1.5"C thermocline than in other turbulence treatments, even when results were corrected for differences in competency among the various treatments, suggest that thermal gradients have a potential commercial importance in both the collection and hatchery production of scallop spat.

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Section: Methodsmentioning

confidence: 89%

Section: Introductionmentioning

confidence: 99%

Effect of thermoclines and turbulence on depth of larval settlement and spat recruitment of the giant scallop Placopecten magellanicus in 9.5 m deep laboratory mesocosms

Pearce¹,

Gallager²,

Manuel³

et al. 1998

Mar. Ecol. Prog. Ser.

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show abstract

“…Because the density structure of the water column was primarily a function of temperature, temperature accounted for most of the variation in larval abundance for most taxa. The presence of larvae in a particular water layer may be the result of changes in their buoyancy and changes in water density (Tremblay & Sinclair 1990. The role of buo yancy in the vertical distribution of gastropod larvae is not known.…”

Section: Patterns In Larval Vertical Distributionmentioning

confidence: 99%

“…Physical (thermoclines, haloclines, pycnoclines) or biological (food patches) discontinuities in the water column can affect larval vertical distribution (Tremblay & Sinclair 1990, Raby et al 1994, Metaxas & Young 1998, Sameoto & Metaxas 2008, Daigle & Metaxas 2011. Physical clines often restrict bivalve larvae to a particular layer (Tremblay & Sinclair 1990 due to changes in buoyancy.…”

Section: Introductionmentioning

confidence: 99%

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Physical and biological factors affect the vertical distribution of larvae of benthic gastropods in a shallow embayment

Lloyd

Meta×as²,

deYoung³

2012

Mar. Ecol. Prog. Ser.

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Marine gastropods form a diverse taxonomic group, yet little is known about the factors that affect their larval distribution and abundance. We investigated the larval vertical distribution and abundance of 9 meroplanktonic gastropod taxa (Margarites spp., Crepidula spp., Astyris lunata, Diaphana minuta, Littorinimorpha, Arrhoges occidentalis, Ilyanassa spp., Bittiolum alternatum and Nudibranchia), with similar morphology and swimming abilities, but different adult habitats and life-history strategies. We explored the role of physical (temperature, salinity, density, current velocities) and biological (fluorescence) factors, as well as periodic cycles (lunar phase, tidal state, diel period) in regulating larval vertical distribution. Using a pump, we collected plankton samples at 6 depths (3, 6, 9, 12, 18 and 24 m) at each tidal state, every 2 h over a 36 and a 26 h period, during a spring and neap tide, respectively, in St. George's Bay, Nova Scotia. Concurrently, we measured temperature, salinity, density, fluorescence (as a proxy for chlorophyll, i.e. phytoplankton density), and current velocity. Larval abundance was most strongly related to temperature, except for Littorinimorpha and Crepidula spp., for which it was most strongly related to fluorescence. Margarites spp., A. lunata, Ilyanassa spp. and B. alternatum exhibited either diel or reverse-diel vertical migration during 1 or both lunar phases. For Crepidula spp., Littorinimorpha, A. occidentalis and Nudibranchia, larval vertical distribution differed between lunar phases. Only the larval vertical distribution of Margarites spp., D. minuta and Ilyanassa spp. varied with tidal state during 1 or both lunar phases. The key factors determining the vertical distribution of gastropod larvae were temperature, fluorescence, and light, although the importance of each factor varied among taxa. Differences in vertical distribution may enable these larvae to partition over a wide range of potential habitats for settlement.

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Modeling spatiotemporal abundance of mobile wildlife in highly variable environments using boosted GAMLSS hurdle models

Smith

Hofner

Lamb

et al. 2019

Ecology and Evolution

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Modeling organism distributions from survey data involves numerous statistical challenges, including accounting for zero‐inflation, overdispersion, and selection and incorporation of environmental covariates. In environments with high spatial and temporal variability, addressing these challenges often requires numerous assumptions regarding organism distributions and their relationships to biophysical features. These assumptions may limit the resolution or accuracy of predictions resulting from survey‐based distribution models. We propose an iterative modeling approach that incorporates a negative binomial hurdle, followed by modeling of the relationship of organism distribution and abundance to environmental covariates using generalized additive models (GAM) and generalized additive models for location, scale, and shape (GAMLSS). Our approach accounts for key features of survey data by separating binary (presence‐absence) from count (abundance) data, separately modeling the mean and dispersion of count data, and incorporating selection of appropriate covariates and response functions from a suite of potential covariates while avoiding overfitting. We apply our modeling approach to surveys of sea duck abundance and distribution in Nantucket Sound (Massachusetts, USA), which has been proposed as a location for offshore wind energy development. Our model results highlight the importance of spatiotemporal variation in this system, as well as identifying key habitat features including distance to shore, sediment grain size, and seafloor topographic variation. Our work provides a powerful, flexible, and highly repeatable modeling framework with minimal assumptions that can be broadly applied to the modeling of survey data with high spatiotemporal variability. Applying GAMLSS models to the count portion of survey data allows us to incorporate potential overdispersion, which can dramatically affect model results in highly dynamic systems. Our approach is particularly relevant to systems in which little a priori knowledge is available regarding relationships between organism distributions and biophysical features, since it incorporates simultaneous selection of covariates and their functional relationships with organism responses.

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Sea scallop larvae Placopecten magellanicus on Georges Bank: vertical distribution in relation to water column stratification and food

Cited by 72 publications

References 31 publications

Effect of thermoclines and turbulence on depth of larval settlement and spat recruitment of the giant scallop Placopecten magellanicus in 9.5 m deep laboratory mesocosms

Effect of thermoclines and turbulence on depth of larval settlement and spat recruitment of the giant scallop Placopecten magellanicus in 9.5 m deep laboratory mesocosms

Physical and biological factors affect the vertical distribution of larvae of benthic gastropods in a shallow embayment

Modeling spatiotemporal abundance of mobile wildlife in highly variable environments using boosted GAMLSS hurdle models

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