SS1.09 Fisheries Population Linkage Spatial and Temporal Variation in Zooplankton
Date: Wednesday, June 12, 2002
Time: 4:15:00 PM
Location: Carson C
 
HeadEJ, Bedford Institute of Oceanography, Dartmouth, Canada, HeadE@mar.dfo-mpo.gc.ca
 
INTERANNUAL VARIATIONS IN HYDROGRAPHY, PLANKTON AND LARVAL HADDOCK SURVIVAL ON THE SCOTIAN SHELF (1998-2001)
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Year-class strength in many commercial species of fish varies greatly and seems to be determined during the first few weeks of life. Survival of the early larvae is thought to depend on the timely presence of food and favourable hydrographic/hydrodynamic conditions. Each spring surveys of the Scotian Shelf allow assessment of biological and hydrographic conditions and each July groundfish surveys provide information on the survival of spring-spawned juvenile fish. During the last 4 years springtime temperatures were cool (1998), warm (1999, 2000), and cold (2001). In addition, the dynamics of the spring bloom (determined by satellite imagery) and the timing of reproduction of the copepod Calanus finmarchicus varied between years. Survival of larval haddock through to settled juveniles on Western and Browns Banks was good in 1998, exceptionally good in 1999 and average in 2000. In 1999, the spring bloom and C. finmarchicus reproduction occurred unusually early, but in 1998 and 2000 C. finmarchicus offspring and larval haddock should have co-occurred. Results from the spring 2001 survey are being analysed, but no settled juvenile haddock were caught in July.