|
|
In 1994, commercial landings of mackerel for the entire northwest Atlantic were roughly 25,000 t. According to the quota report, Canadian landings amounted to 19,000 t, which compares with 12,474 t based on the preliminary catch file established from logbook and purchase slip data. U.S. commercial and recreational landings stood at 5,000 t and 500 t, respectively. On the Scotian Shelf, a total of 44 t of mackerel was caught by Canadian and foreign vessels, with most of this quantity taken by a single Cuban boat. Among Canadian catches, the dominant year-classes were those of 1988, 1990, 1987 and 1991, in that order. The mean age and weight of these fish were 5.7 years and 533 g. A new technique was tested as a means of adjusting virtual population analysis (VPA) using abundance indices. This method, called Integrated Catch Analysis (ICA), was used with the egg index and a U.S. abundance index derived from a spring bottom trawl survey. With ICA, the spawning biomass and the total biomass of the northern population, which spawns mainly in the Gulf of St. Lawrence, and the southern population, which spawns chiefly along the U.S. coast, were estimated at 2 and 3 million tonnes, respectively. These estimates are similar to the figures obtained by some U.S. colleagues, who used a different method of calculation.
|
