| Resumo: |
Sequential population analysis on Long Tail Hake (Macruronus magellanicus)from the Southwest Atlantic. Years 1985-1995. VPA on the Long Tail Hake (Macruronus magellanicus), based on data covering the years 1985 up to 1995, was performed to assess the current state of the stock. Simulation trials, inducing uncertainty about both the natural mortality rate and recruitment were also accomplished, to evaluate the risk of overfishing which is associated to different fishing alternatives, always under the assumption of a single and closed Long Tail Hake population. CPUE data were not appropriate for tunning, so the traditional VPA has been applied. During the period of study, stock biomass and spawning stock biomass showed an increased trend. Long and short-term predictions about yield, stock biomass and spawning stock biomass were made under variable fishing mortality levels. Management measures have been adviced under the assumption of M = 0.35. The analysis showed that a fishing mortality rate F= 0.15 could be recommended as one exploitation alternative without risk of overfishing. On the other hand, F0.1, and F30. BRV involve a higher biological risk. During the last four years, total Long Tail Hake catches have been quite stable, about 40 thousands tons. The recommended fishing mortality would mean to increase 5.5 times fishing effort in relation to that applied in 1995, which would be equivalent to allow for a total catch about 180 thousand tons during 1996, including either Argentine float and Malvinas licensed vessels. The simulations indicates that if equal efforts were successively applied, yields would begin to be stabilized about 145 thousand tons by the year 2000.
|
