Recruitment, post-metamorphic drifting and reproductive output in the herbivorous gastropod Lacuna spp. within kelp canopies and intertidal seaweed communities. Martel, A. Ph.D. Thesis, University of Alberta (Canada), Canada, 1990.
Recruitment, post-metamorphic drifting and reproductive output in the herbivorous gastropod Lacuna spp. within kelp canopies and intertidal seaweed communities [link]Paper  abstract   bibtex   
Pre- and post-settlement factors controlling recruitment of the herbivorous gastropod Lacuna vincta in the canopies of Macrocystis and Nereocystis beds were studied. These factors encompass seasonality of oviposition, larval abundance, in situ larval growth, larval settlement and juvenile migration. Egg masses and adults are abundant on low intertidal algae but are seldom observed in Macrocystis and Nereocystis canopies. The study of cohorts of larvae enabled the determination of the planktonic period (7-9 weeks) as well as the forecasting of timing and intensity of recruitment. Recruitment rates in kelp canopies coincided with patterns of abundance of advanced larvae (\${\textgreater}\$500 \${\textbackslash}mu\$m) in the plankton. Newly-metamorphosed juvenile L. vincta consistently dominate the canopy and observations suggest that shortly after metamorphosis they migrate, via drifting, to the undercanopy or low intertidal area. It is hypothesized that factors such as lack of shelter and increased vulnerability to fish predation are selective pressures favoring this habitat shift. A similar pattern of habitat use by juvenile stages of other benthic invertebrates is reported. Quantitative evidence that several marine benthic invertebrates lacking a planktonic larval stage disperse as juveniles and small adults by drifting in the water column was obtained using off-bottom collectors that mimicked a habitat used by many small molluscs in the intertidal. It is shown that Lacuna can voluntarily produce a mucous thread and initiate drifting. Mucous threads not only reduce sinking rates, but also enhance the animal's ability to attach to nearby substrata. The ultrastructure of drifting mucous threads is described. Finally, recruitment and population dynamics of Lacuna spp. in semi-exposed rocky intertidal seaweed communities, as well as the significance of post-metamorphic drifting and plant morphology on temporal and spatial patterns of abundance of the snails were investigated. It is shown that substratum (algae) choice by juvenile and even adult L. vincta during drifting has significant implications for life-history parameters, including growth, sexual dimorphism, maximum size and, more importantly, fecundity. Females that drift from certain algae which were originally selected at settlement can markedly increase their egg production and lifetime fecundity by colonizing other seaweeds (such as kelp).
@phdthesis{martel_recruitment_1990,
	address = {Canada},
	type = {Ph.{D}.},
	title = {Recruitment, post-metamorphic drifting and reproductive output in the herbivorous gastropod {Lacuna} spp. within kelp canopies and intertidal seaweed communities},
	copyright = {Database copyright ProQuest LLC; ProQuest does not claim copyright in the individual underlying works.},
	url = {http://search.proquest.com.ezproxy.library.ubc.ca/pqdtglobal/docview/230729903/abstract/EEBEA5D6260040ABPQ/1},
	abstract = {Pre- and post-settlement factors controlling recruitment of the herbivorous gastropod Lacuna vincta in the canopies of Macrocystis and Nereocystis beds were studied. These factors encompass seasonality of oviposition, larval abundance, in situ larval growth, larval settlement and juvenile migration. Egg masses and adults are abundant on low intertidal algae but are seldom observed in Macrocystis and Nereocystis canopies. The study of cohorts of larvae enabled the determination of the planktonic period (7-9 weeks) as well as the forecasting of timing and intensity of recruitment. Recruitment rates in kelp canopies coincided with patterns of abundance of advanced larvae (\${\textgreater}\$500 \${\textbackslash}mu\$m) in the plankton. Newly-metamorphosed juvenile L. vincta consistently dominate the canopy and observations suggest that shortly after metamorphosis they migrate, via drifting, to the undercanopy or low intertidal area. It is hypothesized that factors such as lack of shelter and increased vulnerability to fish predation are selective pressures favoring this habitat shift. A similar pattern of habitat use by juvenile stages of other benthic invertebrates is reported.
Quantitative evidence that several marine benthic invertebrates lacking a planktonic larval stage disperse as juveniles and small adults by drifting in the water column was obtained using off-bottom collectors that mimicked a habitat used by many small molluscs in the intertidal. It is shown that Lacuna can voluntarily produce a mucous thread and initiate drifting. Mucous threads not only reduce sinking rates, but also enhance the animal's ability to attach to nearby substrata. The ultrastructure of drifting mucous threads is described.
Finally, recruitment and population dynamics of Lacuna spp. in semi-exposed rocky intertidal seaweed communities, as well as the significance of post-metamorphic drifting and plant morphology on temporal and spatial patterns of abundance of the snails were investigated. It is shown that substratum (algae) choice by juvenile and even adult L. vincta during drifting has significant implications for life-history parameters, including growth, sexual dimorphism, maximum size and, more importantly, fecundity. Females that drift from certain algae which were originally selected at settlement can markedly increase their egg production and lifetime fecundity by colonizing other seaweeds (such as kelp).},
	language = {English},
	urldate = {2016-06-08},
	school = {University of Alberta (Canada)},
	author = {Martel, Andre},
	year = {1990},
	keywords = {Lacuna},
}
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