Yellowfin Tuna, Indian Ocean, Troll/ pole and line

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1 Yellowfin Tuna, Indian Ocean, Troll/ pole and line Yellowfin Tuna, Indian Ocean, Troll/ pole and line Content last updated 7th Mar 2017 Stock: Indian Ocean Management: Indian Ocean Tuna Commission Overview Yellowfin tuna (Thunnus albacares) are found worldwide in tropical and subtropical oceanic waters. There is a single population found throughout the Indian Ocean. Tagging and catch data (longline) both support the theory of a single population distributed throughout the tropical Indian Ocean. Juvenile yellowfin tuna are commonly found associated with juvenile bigeye tuna and skipjack tunas in surface waters. Juveniles are also known to have a strong association with floating objects such as fish aggregating devices (FADs). Adult yellowfin are more commonly found schooling in both surface and subsurface waters. The main spawning grounds occur west of 75 o E, with smaller spawning locations occurring off Sri Lanka, the Mozambique Channel and off of Australia in the eastern Indian Ocean. In the Indian Ocean, purse seine fisheries currently catch the majority of yellowfin tuna, followed by longline, gillnet, handline, troll and pole and line gears. Unlike in other oceans, the artisanal fisheries in the Indian Ocean take a large portion of the total catch, between 20-30%. During 2015, handline, trolling and pole and line fisheries caught 19%, 7% and 5% of yellowfin tuna in the Indian Ocean respectively. Stock Status less risk more risk Indian Ocean yellowfin tuna has been scored a high risk. This is because the stock biomass has fallen below sustainable levels and the population is overfished. Fishing mortality rates are too high and overfishing is occurring. Management less risk more risk The management of yellowfin tuna has been scored a moderate risk. Managers have adopted new measures to address the current status of yellowfin tuna. These measures will not go into place until 2017 and therefore it is too early to determine their success. Bycatch less risk more risk The bycatch in the yellowfin tuna Indian Ocean troll, pole and line and handline fisheries has been scored a low risk. Bycatch and discards in troll, pole and line and hand line fisheries typically makes up a small proportion of the total catch (Kellher 2005) and no vulnerable species are reported (Ardill et al 2011). Baitfish are typically used in troll and pole fisheries. The ratio of tuna to baitfish is around 30:1 and in most cases baitfishing makes up a small proportion of the total fishing mortality for baitfish species (Gillet 2012). Habitat less risk more risk

2 The habitat impact of the yellowfin tuna Indian Ocean pelagic troll, pole and line and handline fishery has been scored as very low risk. In tuna fisheries, which target fish in open waters, there is not likely to be significant interaction with seabed habitats. Outlook Current risk status Outlook Reason Stock High Decreasing Yellowfin tuna are overfished and undergoing overfishing. Management Moderate Stable Managers have adopted measures to address overfishing but the success of these measures is not yet known. Bycatch Low Stable Bycatch in this fishery is very low and impacts to the habitat are minimal. Habitat Very low Stable Type Current Risk Status Outlook Reason Stock Management Bycatch Habitat

3 Stock Status Details less risk more risk Time-trends An updated assessment of yellowfin tuna was conducted during The new assessment included additional longline catch per unit effort series. Several indices of relative abundance were included in the 2015 and updated 2016 assessment, including those from Japan, Indian and Taiwan. All of the indices showed an overall similar trend, with a decrease over time. Catches have increased considerably since the 1950 s. Peak catches occurred during the early to mid 2000 s followed by a decline through 2015 (IOTC 2016)(IOTC 2016b). Stock structure and recruitment Based on tagging and longline catch data, it is currently assumed that there is a single population of yellowfin tuna in the Indian Ocean. Both tagging and longline catch data indicate that yellowfin tuna are spread throughout the entire tropical Indian Ocean (IOTC 2016b). Yellowfin tuna in the Indian Ocean were primarily caught by longline and to some degree by gillnet fisheries between the 1950 s and 1980 s. Due to this, catches were fairly stable and ranged from 30-70,000 t. However, when purse seine vessels began fishing in the Indian Ocean during the 1980 s, all vessels increased their effort and catches increased dramatically to over 300,000 t by the early 1990 s. Catches remained near this level over the next decade but then increased again between 2003 and 2006 to over 535,000 t. In 2012, catches declined to 370,000 t but increased again to over 400,000 t in Piracy in areas off Somalia, Kenya and Tanzania have been a factor in decreased catches of yellowfin tuna between 2007 and This piracy impacted the longline fishery in this region more substantially then the purse seine fishery, due mainly to the use of security personnel on purse seine vessels (European Union and Seychelles) (IOTC 2016b). Data gaps and research priorities Catch and effort data is limited and/or of very poor quality for several main fisheries. For example, there is no catch per unit effort data available for the fresh-tuna Indonesian longline fishery and data since 2006 is not available for the fresh-tuna longline fisheries of Taiwan and China. Information on catch per unit effort from Iran and Pakistan gillnet fisheries is considered insufficient and the Sri Lankan gillnet and longline data is considered to be of poor quality. In addition, information from coastal pole fisheries from areas including Yemen, Indonesia and Madagascar are not available. Size data is not provided by important fisheries including the pole and line and gillnet fisheries of Yemen, Pakistan, Sri Lanka and Indonesia, and the pole and line fisheries of Comoros and Madagascar. Catch data from a number of coastal fisheries from Indonesia, Sri Lanka, Yemen and Madagascar, the Pakistan gillnet fishery are uncertain. In addition, there are issues with non-reporting by industrial purse seine and longline vessels of India (IOTC 2015). References IOTC Status of the Indian Ocean yellowfin tuna (YFT: Thunnus albacares) resource). IOTC-2015-SC18-ES04. IOTC A update of the 2015 Indian Ocean yellowfin tuna stock assessment for IOTC-2016-WPTT IOTC. 2016b. Status of the Indian Ocean yellowfin tuna (YFT: Thunnus albacares) resource). IOTC-2016-SC19ES04.

4 Management Details less risk more risk TAC Information Catch 2015 (t) Advised Catch 2016 (t) Agreed TAC 2016 (t) Advised Catch 2017 (t) 407,575 t 80% of 2014 catches t Stock harvesting strategy Yellowfin tuna are assessed using full analytical models on a regular basis by the Indian Ocean Tuna Commission (IOTC). The last full assessment was conducted in 2015 and an updated assessment was also conducted during The assessment s used a Stock Synthesis III modelling approach and included biological information and catch and effort data (through 2015) from multiple fisheries and countries {IOTC 2016}. The Scientific Committee has recommended that catches of yellowfin tuna be limited to 80% of 2014 levels (IOTC 2015). In 2016, the IOTC adopted new measures to address the status of yellowfin tuna. Under these new measures nations (that reported yellowfin catches in 2014 greater than 5,000 t) are to reduce their catches (gears other than purse seine, longline and gillnet) by 5% from 2014 levels. Additional catch reductions are also mandated in other fisheries (IOTC 2016b). There are interim target and limit reference points in place for yellowfin tuna {IOTC 2016}. Surveillance According to the current IOTC resolution for tropical tunas, countries are to provide advice on appropriate reporting requirements for artisanal fisheries and implement appropriate data collection systems for these fisheries. In addition, the IOTC will maintain an IOTC Record of fishing vessels that are authorized to fish for tuna and tuna-like species in the IOTC area of competence and are 24 m in length and larger or vessels smaller than 24 m in length that fish outside of countries EEZ. Individual countries are required to provide the IOTC with specific information on each of these vessels and are required to take measures to prohibit the fishing for tuna and tuna-like species not included in this IOTC record. Individual countries must also provide the IOTC with a list of foreign vessels granted fishing rights in their respective EEZ s. In addition, in 2014 the IOTC established a programme for monitoring transhipments at sea, in an effort to reduce illegal, unregulated and unreported (IUU) fishing. Information on IUU vessels must also be reported to the IOTC by individual countries. Logbooks, either paper or electronic, are required to be used to collect catch and effort information. Vessel monitoring systems are required on vessels larger than 15 m in length and are used to monitor regulations such as time/area closures {IOTC 2014b}. In 2016 the Commission strengthened measures related to IUU fishing by adopting additional measures related to vessels fishing without nationality and on port state measures to reduce IUU fishing (IOTC 2016b). Logbooks, either paper or electronic, are required to be used to collect catch and effort information. Vessel monitoring systems are required on vessels larger than 15 m in length and are used to monitor regulations such as time/area closures {IOTC 2014}. There continues to be problems with countries reporting all information necessary to monitor compliance with management regulations. However, the Commission has recently adopted additional measures to address issues of non-reporting by countries and developed a working party on the Implementation of Conservation and Management Measures (WPICMM) (IOTC 2016b) References Indian Ocean Tuna Commission (IOTC) Status of the Indian Ocean yellowfin tuna (YFT: Thunnus albacares) resource). IOTC SC18-ES04. IOTC Status of the Indian Ocean yellowfin tuna (YFT: Thunnus albacares) resource). IOTC-2016-SC19ES04. IOTC. 2016b. Conservation and management measures adopted by the IOTC at its 20 th Session. IOTC Circular

5 Bycatch Details less risk more risk References Ardill, D, D Itano, R Gillett, 2011 A Review of Bycatch and Discard Issues in Indian Ocean Tuna Fisheries Gillett, R Report of the 2012 ISSF Workshop: the management of tuna bait fisheries: The results of a global study. ISSF Technical Report International Seafood Sustainability Foundation, Washington, D.C. Kelleher, K Discards in the world s marine fisheries an update. FAO Fisheries Technical paper 470.

6 Habitat Details less risk more risk All content 2018 Seafish. Origin Way, Europarc, Grimsby, DN37 9TZ. This page created on 7th April 2018 at 03:33pm.