Enhancing sustainable mussel industry production and growth through the assessment and removal of constraints in seed supply
Newfoundland is a zone of hybridization between two mussel species, Mytilus edulis and M. trossulus. Newfoundland growers currently use seedstocks consisting of mixtures of both species and their hybrids. Indigenous stocks on most mussel farms consist of widely varying proportions of all three genotypes. Past research has shown that variability in commercially important production characteristics is significantly related to this genotypic variability within and among mussel stocks in Newfoundland. This contributes significantly to high variability in growth, production per hectare, shell morphology, shell color, and meat yield. Low production rates and poor quality product have both been associated with stocks composed of relatively high proportions of M. trossulus. A growing body of research evidence both within and outside Newfoundland has clearly shown that culture of unispecific M. edulis stocks has great potential to improve industry-wide production and product quality and to reduce inter-site variability in these commercially important product characteristics. Thus, the use of transferred unispecific M. edulis stocks by industry has been recommended to replace the current practice of collecting seed on sites with high ratios of M. trossulus. This should, potentially, boost production rates industry-wide with the greatest impact on sites whose indigenous stocks have relatively high proportions of M. trossulus. Additionally, variability in commercially important product characteristics such as shell morphology, color, and meat yield should be reduced. However, the past history of seedstock transfers has shown that unispecific M. edulis stocks have not always consistently out-performed indigenous mixed-species stocks when such seedstocks have been transferred to other growout sites. Reasons for this are currently speculative but genetic variation within the M. edulis genotype is highly suspected. Thus the need exists to both identify sources of unispecific or high-ratio M. edulis stocks and to test their performance on recipient sites to determine their true potential as donor seedstock sites.
This project proposes to address these issues through directed research along two themes: 1) to search for and assess new potential seedstock sources at sites not currently in commercial use and, 2) to more closely assess seedstocks and sites of existing aquaculture leases to determine their potential for development as future donor sources of high quality seed for transfer to recipient growout sites.
2008 - 2010
Atlantic: Newfoundland, Labrador Shelves
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