Thumbnail Image

Overview on neritic tunas bycatch by the national bottom longliners in Madagascar








Also available in:
No results found.

Related items

Showing items related by metadata.

  • Thumbnail Image
    Meeting
    An overview of the bycatch landed by local and foreign tuna longliners in Mauritius for the period 2009 to 2012 2013
    Also available in:
    No results found.

    This paper presents by-catch estimates landed by tiol and foreign longliners fishing inside and outside the EEZ of Mauritius for the period 2009 to 2012. Some 100 licences are issued annually to foreign longliners to fish in the Exclusive economic zone (EEZ) of Mauritius. The average annual landing from these vessels during the period under report amounted to 3 102 tonnes of albacore tu which is the targeted species followed by 796 tonnes of yellowfin tu (Thunnus albacares), 360 tonnes of big-ey e tu (Thunnus obesus) and 1106 tons of by-catch comprising billfish, other tu-like species and sharks. A total of 21 196 tonnes of tu and tu-like species was transhipped in Port-Louis by non-licensed fishing vessels targeting albacore (Thunnus alalunga), from 2008 to 2012. The proportion of by-catch landed during this period varied between 28.9% and 39.4%. The total catch landed by non-licensed longliners targeting big-eye tu has increased over the years from 3495 tonnes in 2008 to 8125 tonnes i n 2012. The proportion of by-catch in the total catch seems to be the same (33.1%-47.0%) as compared to the level of by-catch of albacore-targeting fishing vessels (37.9%-39.4 %). The proportion of by-catch landed by longliners targeting swordfish (Xiphias gladius) varied between 37.2% to 49.6%. A comparison of shark landings by tu longliners and swordfish-targeting longliners was carried out: the levels of sharks in the total catch of longliners targeting big-eye tu are higher (7.9%-20.2%) than those targeting albacore (3.6%-8.03%). However, the catch of sharks was very significant in swordfish-targeting vessels varying between 24.3%-39.1% of the total catch in comparison to albacore-targeting fleets and big-eye targeting fleet. Sharks landed by swordfish-targeting vessels consisted mainly of blue shark (Prioce glauca) (74.2-84.2%) followed by moro (Isurus oxyrhinchus) (7.1-20.0%) and mako shark (Isurus paucus) (4.6-9.2%). Moreover, Mauritius has a small number of tiol boats targeting swordfish that operate in its EEZ. These boats also land a considerable amount of non-targeted tu and tu-like species including sharks. The by-catch levels for tiol boats targeting swordfish was higher (50.8%- 52.7% of the total catch) as compared to the FAD fishery whose by-catch varied between 27.9%- 42.9%.
  • Thumbnail Image
    Meeting
    Sharks: Bycatch in the tuna longline fishery in the Indian Ocean by Thai tuna longliners in 2012 2013
    Also available in:
    No results found.

    This report was based on the data extracted from fishing logsheets by two Thai tu longliners mely, “Mook Andaman 018” and “Mook Andaman 028”, which declared to Department of Fisheries, Thailand. Data from their logsheets displayed important information of their fishing operation and effort. In 2012, fishing grounds were mainly in the Western coast of Indian Ocean. The total catches were 470.40 tons with 387 days of fishing effort. The average catch rate of total catch was 10.83 individual fish/1 ,000 hooks. The major catch species were bigeye tu (Thunnus obesus), yellowfin tu (T. albacares), swordfish and shark. Sharks are present as an important role in the ocean ecosystem. The fishing operation was reduced their population. Among the bycatch of tu longline fishery, The percentage of sharks to the total catch is 4.64% by weight and 3.94% by number. Numbers of shark were 544 individual fishes with 18,528 kg. The catch rate was 0.5 individual fish/1,000 hooks, 17.10 kg/1,000 hooks. Catch data of sharks are classed into a single group of “sharks”, due to species unidentification.
  • Thumbnail Image

Users also downloaded

Showing related downloaded files

No results found.