1. Chilean fleet operations on the jack mackerel fishery 2004 Document prepared for the Third Bilateral Consultation on Fisheries Conservation between the Governments of Chile and the People´s Republic of China, April 18-19-20, 2005.

2. Chilean Fleet Operation The jack mackerel fleet operation in the centre south zone during 2004 was similar to that of 2003, with an operative fleet of 44 fishing vessels. This fleet shows a decrease on the fishing effort of 60% with respect to 1997, when fisheries management started in order to recover the biomass of the resource.

3. Catches In 2004 the total jack mackerel catch quota allowed between the I and X regions registered 1.48 million tons, it was caught almost completely. (98%).

4. Catches Two different periods can be observed in the jack mackerel landings on 2004, the first one between January and August with high catches (monthly average for this period of 150,000 tons) and a second period of low catches between September and December.

5. Catches Jack mackerel catches outside the Chilean EEZ during 2004 reached 297,000 tons, concentrated between June and October 2004.

6. Space-temporary distribution of fleet operations The jack mackerel fleet operation during 2004 followed a very similar pattern to that showed during 2003. Thus the operation between January and May was focused in the centre-south zone within the Chilean EEZ, and it further operated outside the EEZ between June and September. Finally, the fleet operation between October and December occurred in the coastal area within the EEZ, with low lever catch.

8. Biological characteristics during 2004. During 2004, a jack mackerel mode increase was observed, this is explained by the fortification of the greater individuals and by a decrease of the recruitment (juvenile contingent), with a structure size between 17 and 62 cm (Fork Length), and a main mode of 29 cm Fork Length.

9. Biological characteristics during 2004. In terms of the resource state of maturity during 2004, the figure shows that between January and July the females are in a state of initial maturity and that between August and December a progressive level of maturity is observed.

10. Biological characteristics during 2004. The Gonadosomatic Index, shows that during 2004 (February and July) there is a rest in the spawning and reproductive processes, and a progressive increase of the sexual maturity between August and December. When comparing this index with the historical information, we can observe a loss of the reproductive potential due to the incorporation of juveniles to the process, and since the occurrence of “El Niño 97-98”, there has been no index recovery in the long term.

11. Biological characteristics during 2004.

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