The effect of sock spacing on the productivity of ...
|Title||The effect of sock spacing on the productivity of mussel on a longline system|
|Author(s)||A. Drapeau, L. A. Comeau, T. Landry, Henrik E. Stryhn, J. Davidson|
|Publisher||Gulf Fisheries Centre|
|Place published||Moncton, N.B.|
In suspended blue mussel (Mytilus edulis) culture, the link between sock spacing
and mussel performance on a longline system has never been experimentally
demonstrated. Therefore, the objective of this trial was to compare productivity of
mussel socks spaced (sock spacing treatments [Tx]) 10 cm, 20 cm, 40 cm, 60 cm and 80
cm apart on a longline. A large-scale experiment was conducted in distinct leases of
Tracadie Bay, PEI over a one-year production cycle. Shell growth and survival of premarket
mussels were positively associated with higher sock spacing treatments, while
condition index displayed no temporal and spatial relations to sock spacing treatments.
In two of the four experimental sites, results showed significantly greater growth and
survival levels on mussel socks spaced 80 cm apart (i.e. Tx 80) at the end of the
production cycle. Shell growth increased by 8% (3.4 mm) and 7% (3.4 mm), while
survival was 42% (233 mussels/m) and 18% (87 mussels/m) higher when comparing low
density levels (Tx 80) to high density levels (Tx 10) of cultured mussels. When all
management strategies (i.e. socking density and seed size) were kept constant, the
association between sock spacing treatments and productivity were non-significant. The
significant differences between sock spacing treatments at two of the four sites may be
due to high initial socking density and smaller seed size. Sites displaying significant
associations were respectively characterized by having 58% and 47% more mussels per
meter, while seed mussels were 46% and 23% smaller. Dense aggregation of bivalves at
the farm level and inside mussel socks may lead to intra-specific competition between
individuals as food demand at the local scale may exceed food supply and ultimately
limit growth. Food levels at the local scale were not measured during this study, but are
documented to be highly variable temporally and spatially within this growing area.
Using APA 6th Edition citation style.
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