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| Marine Resource Fact Sheet |
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| | Yellowfin tuna - Indian Ocean, 2005 |
| | Yellowfin tuna Indian Ocean |
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| | Owned by | Indian Ocean Tuna Commission (IOTC)
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| Main Descriptors | Considered a single stock: Yes
Spatial Scale: Regional
Considered a management unit: Yes |
| Considered a single stock: A group of individuals in a species occupying a well defined spatial range independent of other stocks of the same species. It can be affected by random dispersal movements and directed migrations due to seasonal or reproductive activity. |
| Spatial Scale: Spatial scale contains a standard term such as Global, Regional (e.g. for the whole Atlantic), sub-regional (e.g. for a part of the Atlantic), national, local (for sub-national levels). |
| Considered a management unit: An aquatic resource or fishery is
declared as [Fishery] Management Unit if it is
effectively the focus for the application of selected
management methods and measures, within the broader
framework of a management system. According to the FAO
Glossary for Responsible Fishing, "a Fishery Management
Unit (FMU) is a fishery or a portion of a fishery
identified in a Fishery Management Plan (FMP) relevant
to the FMP's management objectives." FMU's may be
organised around fisheries biological, geographic,
economic, technical, social or ecological dimensions ,
and the makeup and attribute of a fishery management
unit depends mainly on the FMP's management
objectives. |
| Jurisdictional distribution: Jurisdictional qualifier (e.g.
"shared", "shared - highly migratory") of the aquatic
resource related with its spatial distribution. |
| Environmental group: Classification of the aquatic
resource according to the environmental group (e.g.
pelagic invertebrate, or demersal fish) to which the
species belong. |
| | | | | | Habitat and Biology Climatic zone: Tropical Bottom type: Unspecified Depth zone: Unspecified Horizontal distribution: Oceanic Vertical distribution: Pelagic Geographical Distribution Jurisdictional distribution: Highly migratory Geo References  | | Distribution of Yellowfin tuna - Indian Ocean
| iotc Comp | IOTC: IOTC competence area |
| | | | | | Other georeferences
| FAO major areas | 51: Indian Ocean, Western | | 57: Indian Ocean, Eastern |
| | | | | | Intersecting Major FAO areas and LME areas |
The following area codes have been found as intersecting the distribution of Yellowfin tuna - Indian Ocean | FAO major areas | 51:
Indian Ocean, Western | | 57:
Indian Ocean, Eastern | | (LME) Large Marine Ecosystem Areas | 30: Agulhas Current | | 31: Somali Coastal Current | | 32: Arabian Sea | | 33: Red Sea | | 34: Bay of Bengal | | 39: North Australian Shelf | | 42: Southeast Australian Shelf | | 43: Southwest Australian Shelf | | 44: West-Central Australian Shelf | | 45: Northwest Australian Shelf |
Resource Structure Considered a single stock: Yes Assessment The stock assessment was undertaken in 2005 using data up to 2003 Management Considered a management unit: Yes Biological State and Trend Exploitation state: Fully exploited
Considering all the stock indicators and assessments, as well as the recent trends in effort and total catches of yellowfin, the Scientific Committee considered that: - Fishing mortality rates between 1999 and 2002 were probably slightly below or around Fmsy, and total catches during that period, at an average level of 347,000 t, were probably close to, or possibly above MSY. Total catches in 2003 and 2004 were substantially above MSY; see below for interpretation of the possible reasons for and possible effects of these catches. In these circumstances, any further increase in both effective fishing effort and catch above average levels in 1999 - 2002 should be avoided.
- The current fishing pressure on juvenile yellowfin by both purse seiners fishing on floating objects and artisanal fisheries is likely to be detrimental to the stock if it continues, as fish of these sizes are well below the optimum size for maximum yield per recruit estimated in 2002.
- The Scientific Committee also noted that juvenile yellowfin tuna are caught in the purse-seine fishery that targets primarily skipjack tuna. Some measures to reduce the catches of juvenile yellowfin tuna in the FAD fishery will be accompanied by a decrease in the catches of skipjack tuna.
Source of information “Report of the Eighth meeting of the IOTC Scientific Committee (2005)” IOTC Scientific Committee 2005 IOTC-2005-SC-R[EN+FR]. IOTC. |
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