Dr. Joe Wroblewski
Investigation of local fisheries resources of the Labrador
coast: J. Wroblewski, C. Parrish.
This is a subproject of ‘Coasts Under Stress’ looking
at the nutritional value of cultured finfish and shellfish, in
comparison to seafood from wild harvest. The goal is to provide
scientific information for government policy on aquaculture
development in Newfoundland and Labrador. In addition, the living
marine resources of coastal Labrador are being studied. These have
not been scientifically documented to date because of the
remoteness of Labrador. Participatory research is being conducted
with fishers to incorporate their ecological knowledge into
scientific hypothesis testing, with the objective of improving
their involvement with stock assessment science and management of
local stocks. The reliability of the colouration of cod as an index
of stock structure is being investigated. Fishers recognize bay cod
by their reddish-brown colouration, while offshore cod are
recognized by their grey-white coloration. Offshore cod are
countershaded as an adaptation to their deep water habitat, while
the reddish-brown coloration of shallow-water cod arises from a
diet rich in carotenoids.
Bio-physical modeling of bay-scale populations of marine
fish: J. Wroblewski, B. deYoung (Physics), Y. Chen (U of
Maine).
The hypothesis to be tested is that bay-scale populations of marine
fish exist where adults display homing-to-spawn behaviour and local
oceanographic conditions promote retention of eggs and survival of
larvae. Computer models are being used to simulate homing-to-spawn
behaviour of cod and physical oceanographic circulation in bays
which support local populations of Atlantic cod to seek
commonalities. Bays known to support local populations of cod all
have major freshwater input during the spring spawning season.
Surface stratification may play a role in retention and larval
survival. The large volume of runoff in springtime may be important
to the spring phytoplankton bloom and production of coastal cod.
Simulations will determine the assessment sampling required to
detect mixing between coastal populations of fish.