Recovery Just Begins

Has the state of emergency come to the end? This does not seem to be the conclusion followed from INIDEP’s (National Institute for Fisheries Research and Development) last Technical Report on hake. In fact, the report states that if the same effort level were maintained, a catch of about 300,000 tons of hake could be obtained in the stock south of 41º parallel.

Besides, it clearly recommends maintaining that effort level; otherwise, the still fragile recovery process of the resource, which was initiated three years ago, could be in danger.

Let us remember that the declaration of emergency of the resource was based on evidence of abundance reduction, geographical distribution, and deterioration of the population age structure.

Even though recovery symptoms can be observed, the abundance present in 1996 has still not been recovered, as shown in Figure 1.

Figure 1. Hake biomass south of 41º S. In blue, the biomass estimated by means of the swept area method with research vessels. In lilac, the total biomass calculated with the virtual population analysis (VPA); in green, the reproductive biomass calculated with the same method.

According to the projections for 2003, the reproductive biomass would exceed the 400,000 ton critical limit, and there would be a significant recovery in terms of total biomass, although it does not reach the levels prior to 1998.  Anyway, it is necessary to wait and see whether these projections are proved by swept area data obtained from global campaigns and by  the Catch Per Unit Effort (CPUE).

As regards the latter, the available information does not seem so optimistic, as shown in Figure 2.

Figure 2. Standard effort and CPUE over hake south of 41º S. 1990-2002

Last year, standard CPUE was 2,374 t/h, much less than 1995 CPUE (4,075 t/h) while the standard effort (trawling hours) was very similar to last year effort. This shows much less abundance.

Figure 3. First semester hake landings of the of shore ice chilling fishing fleet. 1996-2003

A sign of this derives from the comparison of the ice chilling fishing fleet landings during the first semesters of the last seven years, where it can be noticed that, with similar efforts and even less restrictions than last year, catches are smaller. Likewise, this fact can be perceived in the extension of fishing trips to 12 days again, as they were in 1999.

In the same way, Figure 2 shows a tendency towards an increase in effort, due to the growing exploitation of the resource by the factory trawler (freezer) fleet, after the significant 2000 reduction. If this tendency proved to continue, it could bring about dangerous situations close to collapse, already lived in the past.

The present age structure is still very far from being a normal population structure, since the age 4 and the subsequent ones have practically disappeared, as shown in Figure 4.

Figure 4. Hake population age structure south of 41º S

Considering 1987 age distribution as a normal distribution, due to the low level of  exploitation, it can be noticed that 2002 age distribution is still a post-war population pyramid, if likened to the human population case. There exists an evident predominance of the age 2 as a result of the great reproductive success and the important restrictions on 2000 fishing. However, the fall towards the age 4 is sudden, and the age 1 is symptomatically smaller than the age 2 since the recruitments later than 2000 have been of a normal-low level. This shows the fragility of the recovery process and the efforts still to be made in order to definitively stabilize the hake population south of 41º.

The present available information makes it necessary to be extremely prudent towards optimism, and to oppose decidedly the new tendency to increase the effort that it has been shown in the last two years.

On the other hand, INIDEP recommends that the effort should not be increased, and insists on advice given in previous years: to urgently re-establish satellite monitoring in order to avoid high catch of juvenile fish in the banned zone, and to recover the on board observer programme maintaining the level it was in 2000.

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