Northwest Atlantic fish stocks: actual status based on the june 2000 NAFO Scientific Council assessments
2001
Melo, A.A. de | Alpoim, R. | Vargas, J.
In 2000 the cod of northern Grand Bank from Div. 2J3KL and the cod of southern Grand Bank from Div. 3NO remained with low recruitments at age 3 and high levels of total mortality, well above the natural mortality usually accepted for cod stocks. The maintenance of the northern cod at an historical low level reflects the predation by harp seals, estimated to be in 1998 and 1999 above 50 000 ton and mainly composed of pre-recruited juveniles (ages 0 to 2). The Flemish Cap cod is also kept at a very low level due to the exhaustion, by trawl fishing, of all good year classes over the past 20 years. With recruitment almost null since 1995 and the size and fecundity of the spawning component declining, the recovery of this cod stock is not yet foreseen. According to 1999 VPA, and both spring and autumn Canadian survey series, American plaice of Div. 3LNO sharply declined from the mid eighties to the mid nineties. Between 1997 and 2000 several bottom trawl surveys presented important increases in their biomass and spawning biomass indices, that can be partly explained by an increase of the catchability/availability of this species on the shallower grounds of the Grand Bank. However, the present biomass from Canadian survey series is still well below the correspondent average level of biomass occurring at the turn of the last decade. For the first time an analytical assessment has been carried out for the Greenland halibut stock component of Sub Area 2 and Div. 3KLMNO with several models that used for calibration abundance at age indices from the Canadian autumn survey on Div. 2J and 3K, the EU summer survey on Div. 3M and the standardised observed cpue series for the Portuguese fleet. With the drop of the fishing mortality since 1995 all models give a constant increase in biomass, supported by a sequence of exceptionally good year classes. The actual stock size is the maximum for the most recent period starting at 1975. Short and medium term projections show that an increase of the catch in 2001 up to 44 000 ton will not increase the present level of fishing mortality
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