Graduate Students
MSc Student,
Centre for Aquaculture and Environmental Research,
University of British Columbia
Invertebrate fouling community composition and succession associated with Pacific oyster deep-water suspended tray culture
Jody Shields
M.Sc Student, University of Windsor
Population Structure and Dynamics of the Mytilus species complex in Hybrid Zones on Vancouver Island , BC .
Debbie Paltzat
M.Sc Graduate, University of British Columbia
Completed December 2005
Biological feasibility of suspended Pacific oyster (Crassostrea gigas Thunberg) and California sea cucumber (Parastichopus californicus Stimpson) polyculture
Undergraduate Students
Student Projects 2004
Heidi Lydersen
Undergraduate Student, Department of Fisheries and Aquaculture, Vancouver Island University
Invertebrate communities associated with deep-water, suspended oyster culture in BC
Thurston Helm
Department of Fisheries and Aquaculture, Vancouver Island University
Infaunal community composition in relation to deep-water suspended oyster farms in BC
Bree Dixon
Undergraduate Student, Dept. of Fisheries and Aquaculture, Vancouver Island University
Mussel filtration and biodeposition
Undergrad Projects from 2005
Jody Shields
MSc Student
Great Lakes Institute for Environmental Research
University of Windsor
Supervisor: Dr. Daniel D. Heath
Co-supervisor: Dr. Penny Barnes
Thesis Project
Population Structure and Dynamics of the Mytilus species complex in Hybrid Zones on Vancouver Island , BC .
The Mytilus species complex was traditionally thought to be a single panmictic population with little geographic variation in the northern hemisphere, as is often thought of marine species with high dispersal potential (Hilbish 1996). Three sibling species in the genera Mytilus are now recognized through molecular genetic variation: Mytilus trossulus, Mytilus edulis, and Mytilus galloprovincialis (Suchanek et al. 1997). M. trossulus is native to British Columbia while both M. edulis and M. galloprovincialis were introduced for aquaculture purposes. These species are known to hybridize wherever there are sympatric populations (Hilbish 1999) while allopatric populations of Mytilus remain genetically distinct (Rawson et al. 1996). Morphologically these species cannot reliably be distinguished, thus genetic techniques must be used to identify individuals to species level (Heath et al. 1995). The taxanomic status of the genus Mytilus has been actively debated and depending on which characteristics are investigated, has been said to include three separate species, subspecies or a single panmictic population (Ringos and Cunningham 2005).
Studies of the Mytilus species complex may further our understanding of the evolutionary consequences of hybridization and its relationship with speciation and adaptation. Hybrid zones are attractive in that they represent the interaction among adaptation, reproductive isolation and speciation (Ringos and Cunningham 2002, Toro et al. 2004). If hybrid offspring are viable there is potential for introgression among species resulting in novel genetic variation (Toro et al. 2004).
The current study seeks to investigate the hybrid zones of Vancouver Island , BC to determine the level of gene flow between puretype and hybrid populations and examine the genetic consequences of hybridization on the physiology of marine mussels in the genus Mytilus .
Contact Info
Office Phone: 519-253-3000 ext 4244
Email: shieldsj@uwindsor.ca
Education
BSc 2000-2004 University of Victoria, Victoria BC
Major – Biology
Minor- Environmental Studies
Post Degree Diploma 2004-2005 Fisheries and Aquaculture Vancouver Island University , Nanaimo BC
Debbie Paltzat
Debbie Paltzat is a recent University of BC M.Sc. graduate. Debbie was sponsored by Dr. Barnes, in the EIRP lab, for the duration of her research.
Thesis Project
Biological feasibility of suspended Pacific oyster (Crassostrea gigas Thunberg) and California sea cucumber (Parastichopus californicus Stimpson) polyculture
An integrated system of marine aquaculture with farmed animals at different trophic levels has the potential to increase the efficiency and productivity of intensive monoculture systems while reducing waste products and environmental impacts.
Polyculture has been applied to sea cucumber production in China ; however, in other parts of the world, suitable culture methods for commercial species have not yet been developed or are in experimental stages. In this study, field investigations were undertaken at two Pacific oyster (Crassostrea gigas) culture sites in British Columbia to examine the potential for California sea cucumber (Parastichopus californicus) growth and production when in polyculture with suspended oysters and the potential for this polyculture to reduce the effects of biodeposition at oyster culture sites. The production rate of feces/pseudofeces from oyster strings was determined and samples of the particulate waste material were analyzed for organic carbon and nitrogen content. The utilization of this material as a food source by Parastichopus californicus was measured quarterly by growth (i.e. muscle development) and survivorship of the sea cucumbers in situ under oyster culture rafts. Laboratory experiments were conducted to identify the uptake rate of this material by P. californicus.
The study determined that this species of sea cucumber could survive and grow on the amount of organic matter deposited below the oyster rafts and significantly decrease the ecological footprint of the oyster farms.
Education
M.Sc., University of British Columbia
B.Sc. (Environmental Biology), University of Alberta , 2000.
Heidi Lydersen
Heidi Lydersen's NSERC Undergraduate Summer Research Award (Summer 2004) project was to investigate the diverse invertebrate communities associated with deep-water, suspended oyster culture in BC.
The biodiversity of these systems must be investigated in order to catalogue species present in BC's coastal ecosystems and, equally importantly, to determine the role of the communities in the environmental interactions of shellfish aquaculture. For example, these culture systems act as artificial living reefs and their role in ecosystem processes may include providing substrate for the larval settlement of other commercial species. Also, studies of invertebrates growing on oyster rafts in Washington State , USA , have yielded a surprisingly high number of invasive species, as well as valuable data on range extensions. Heidi's study represents the first study on the invertebrate biodiversity of oyster rafts in BC.
Thurston Helm
Thurston Helm's NSERC Undergraduate Summer Research Award (Summer 2004) project was to study infaunal community composition in relation to deep-water suspended oyster farms in B.C.
Despite the fact that B.C.'s shellfish industry is poised for expansion, very little information is available on the potential benthic impact of the deep-water farms. Biodeposition from bivalve culture, in which bivalves feed on natural phytoplankton, is largely composed of feces and pseudofeces. This packaging of phytoplankton and other seston into larger particles by the oysters may cause locally increased deposition of material to the benthos. Biodeposition under bivalve culture facilities may also include sloughed fouling organisms and cultured organisms. The 3-dimensional culture facility itself may encourage sedimentation through the baffle effect, whereby both wave amplitude and current speeds are reduced within the farm. Faunal community change in relation to an organic enrichment gradient is well documented for the marine benthos: in general, organic loading of sediment leads to a reduction in infaunal species diversity and an increase in the abundance of opportunistic species. Hence, infaunal community structure can be a sensitive indicator of sedimentary conditions and, therefore, useful in the detection of environmental impacts. The results of Thurston's study, in conjunction with sediment chemistry data and biodeposition rates collected as part of the larger particulate study funded by the BC Aquaculture Research and Development Committee, will help to determine methodologies applicable to monitoring the environmental effects of biodeposition from shellfish aquaculture in local benthic environments.
Bree Dixon
VIU Dept. of Fisheries and Aquaculture Undergraduate Research Project
The project is to evaluate filtration and biodeposition rates of commercial mussels.
The filtration and biodeposition rates (and absorbance efficiencies) of commercially reared bivalves are an area of economical and ecological importance in B.C. They are an integral component in the determination of site suitability and culture techniques used by shellfish growers. With some knowledge of weight specific filtration rates, growers can adjust culture techniques (i.e. densities) to maximize growth with respect to the primary productivity and water flow in the area. Expansion of the industry requires scientific research to establish the impacts on the underlying and surrounding benthic habitat posed by current operations. It is also necessary to evaluate the consequences of introducing large harvested biomasses to coastal areas based on primary productivity, oceanography and interactions with native flora and fauna.