scholarly journals Standardization of a geo-referenced fishing dataset for the IndianOcean Bigeye Tuna, <i>Thunnus obesus</i> (1952–2014)

2016 ◽  
Author(s):  
Teja A. Wibawa ◽  
Patrick Lehodey ◽  
Inna Senina
Keyword(s):  
Indian Ocean ◽  
Tropical Indian Ocean ◽  
Fishing Effort ◽  
Purse Seine ◽  
Historical Period ◽  
Data Sets ◽  
Bigeye Tuna ◽  
Thunnus Obesus ◽  
Modelling Studies ◽  
Tuna Fisheries

Abstract. Geo-referenced catch and fishing ­effort data of the bigeye tuna fisheries in the Indian Ocean over 1952–2014 were analysed and standardized to facilitate population dynamics modelling studies. During this sixty-two years historical period of exploitation, many changes occurred both in the fishing techniques and the monitoring of activity. This study includes a series of processing steps used for standardization of spatial resolution, conversion and standardization of catch and effort units, raising of geo-referenced catch into nominal catch level, screening and correction of outliers, and detection of major catchability changes over long time series of fishing data, i.e., the Japanese longline fleet operating in the tropical Indian Ocean. A total of thirty fisheries were finally determined from longline, purse seine and other-gears data sets, from which 10 longline and four purse seine fisheries represented 96 % of the whole historical catch. The geo-referenced records of catch, fishing effort and associated length frequency samples of all fisheries are available at doi.pangaea.de/10.1594/PANGAEA.864154.

scholarly journals Standardization of a geo-referenced fishing data set for the Indian Ocean bigeye tuna, <i>Thunnus obesus</i> (1952–2014)

2017 ◽  
Vol 9 (1) ◽  
pp. 163-179 ◽  
Author(s):  
Teja A. Wibawa ◽  
Patrick Lehodey ◽  
Inna Senina
Keyword(s):  
Indian Ocean ◽  
Tropical Indian Ocean ◽  
Fishing Effort ◽  
Purse Seine ◽  
Historical Period ◽  
Bigeye Tuna ◽  
Dynamics Modeling ◽  
Data Set ◽  
Thunnus Obesus ◽  
The Indian Ocean

Abstract. Geo-referenced catch and fishing effort data of the bigeye tuna fisheries in the Indian Ocean over 1952–2014 were analyzed and standardized to facilitate population dynamics modeling studies. During this 62-year historical period of exploitation, many changes occurred both in the fishing techniques and the monitoring of activity. This study includes a series of processing steps used for standardization of spatial resolution, conversion and standardization of catch and effort units, raising of geo-referenced catch into nominal catch level, screening and correction of outliers, and detection of major catchability changes over long time series of fishing data, i.e., the Japanese longline fleet operating in the tropical Indian Ocean. A total of 30 fisheries were finally determined from longline, purse seine and other-gears data sets, from which 10 longline and 4 purse seine fisheries represented 96 % of the whole historical geo-referenced catch. Nevertheless, one-third of total nominal catch is still not included due to a total lack of geo-referenced information and would need to be processed separately, accordingly to the requirements of the study. The geo-referenced records of catch, fishing effort and associated length frequency samples of all fisheries are available at doi:10.1594/PANGAEA.864154.

Vertical distribution of bigeye tuna Thunnus obesus in the tropical Indian Ocean

2013 ◽  
Vol 20 (3) ◽  
pp. 660-671 ◽  
Author(s):  
Xuezhong CHEN ◽  
Shenglong YANG ◽  
Yu Zhang ◽  
Wei FAN ◽  
Yumei WU
Keyword(s):  
Indian Ocean ◽  
Vertical Distribution ◽  
Tropical Indian Ocean ◽  
Bigeye Tuna ◽  
Thunnus Obesus

scholarly journals Effects of El Niño–Southern Oscillation events on catches of Bigeye Tuna (Thunnus obesus) in the eastern Indian Ocean off Java

2013 ◽  
Vol 111 (2) ◽  
pp. 175-188 ◽  
Author(s):  
Mega L. Syamsuddin ◽  
Sei-Ichi Saitoh ◽  
Toru Hirawake ◽  
Samsul Bachri ◽  
Agung B. Harto
Keyword(s):  
Indian Ocean ◽  
El Niño ◽  
El Nino ◽  
Southern Oscillation ◽  
Eastern Indian Ocean ◽  
El Niño Southern Oscillation ◽  
El Nino Southern Oscillation ◽  
Bigeye Tuna ◽  
Thunnus Obesus

scholarly journals Characteristics Fishing Areas of Bigeye Tuna (Thunnus Obesus) in Depth of 155 m Based on Remotely Sensed Data

2020 ◽  
Vol 5 (1) ◽  
pp. 62-70
Author(s):  
Achmad Fachruddin-Syah ◽  
Jonson Lumban Gaol ◽  
Mukti Zainuddin ◽  
Nadela Rista Apriliya ◽  
Dessy Berlianty ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Remotely Sensed ◽  
Eastern Indian Ocean ◽  
Bigeye Tuna ◽  
Remotely Sensed Data ◽  
Surface Salinity ◽  
Chl A ◽  
Fishing Vessels ◽  
Thunnus Obesus ◽  
Daily Data

Bigeye tuna (Thunnus obesus) is one of the commercially important pelagic species that caught mostly in the eastern Indian Ocean. This species prefers to stay close, and is usually below the thermocline layer. Remotely sensed data was used to determine the characteristics of Bigeye tuna fishing areas at a depth of 155 meter. Fishing vessels for Bigeye tuna were obtained from vessel monitoring systems (VMS) from January through December, 2015-2016. Daily data on sub-surface temperature (SST), sub-surface chlorophyll-a concentration (SSC), and sub-surface salinity (SSS) were obtained from the INDESO Project website. All oceanographic parameter data were selected at a depth of 155 m. The position of Bigeye tuna and oceanographic data were then grouped into 2 group monsoon, southeast monsoon (April – September) and northwest monsoon (October – March). The results showed that, during the southeast and northwest monsoon, Bigeye tuna mostly found in SSC of 0.03 – 0.05 mg/m3, SST of 16° - 18°C and salinity of 34 psu. These results showed that at depth of 155 m, Bigeye Tuna prefers to stay in small chl-a (0.03 – 0.04 mg/m3), low SST (16° - 18°C) and salinity of 34 psu. These information were essential and could be used to support fisheries management decisions especially for Bigeye Tuna in the eastern Indian Ocean.

Direct age estimation, interpretation and precision of bigeye tuna (Thunnus obesus) in the Southern Indian Ocean using vertebrae

2020 ◽  
Author(s):  
Cheng Zhou ◽  
Liuxiong Xu ◽  
Xuefang Wang ◽  
Guoping Zhu ◽  
Rong Wan ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Age Estimation ◽  
Southern Indian Ocean ◽  
Bigeye Tuna ◽  
Thunnus Obesus

Interannual variation of bigeye tuna (Thunnus obesus) hotspots in the eastern Indian Ocean off Java

2016 ◽  
Vol 37 (9) ◽  
pp. 2087-2100 ◽  
Author(s):  
Mega Syamsuddin ◽  
Sei-Ichi Saitoh ◽  
Toru Hirawake ◽  
Fadli Syamsudin ◽  
Mukti Zainuddin
Keyword(s):  
Indian Ocean ◽  
Interannual Variation ◽  
Eastern Indian Ocean ◽  
Bigeye Tuna ◽  
Thunnus Obesus

scholarly journals Spatial management of Indian Ocean tropical tuna fisheries: potential and perspectives

2014 ◽  
Vol 71 (7) ◽  
pp. 1728-1749 ◽  
Author(s):  
David M. Kaplan ◽  
Emmanuel Chassot ◽  
Justin M. Amandé ◽  
Sibylle Dueri ◽  
Hervé Demarcq ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Fishery Management ◽  
Tropical Indian Ocean ◽  
Catch Per Unit Effort ◽  
Management Options ◽  
Fish Movements ◽  
Spatial Management ◽  
Spatio Temporal ◽  
Tuna Fisheries ◽  
Tropical Tuna

Abstract Effective use of spatial management in the pelagic realm presents special challenges due to high fish and fisher mobility, limited knowledge and significant governance challenges. The tropical Indian Ocean provides an ideal case study for testing our ability to apply existing data sources to assessing impacts of spatial management on tuna fisheries because of several recent controversial spatial closures. We review the scientific underpinnings of pelagic MPA effects, spatio-temporal patterns of Indian Ocean tuna catch, bycatch and fish movements, and the consequences of these for the efficacy of spatial management for Indian Ocean tropical tuna fisheries. The tropical Indian Ocean is characterized by strong environmental fluctuations, regular seasonal variability in catch, large observed tuna displacement distances, relatively uniform catch-per-unit-effort and bycatch rates over space, and high fisher mobility, all of which suggest significant variability and movement in tropical tuna fisheries that are simply not well adapted to static spatial closures. One possible exception to this overall conclusion would be a large time/area closure east of Somalia. If closed for a significant fraction of the year it could reduce purse-seine bycatch and juvenile tuna catch. Dynamic closures following fish migratory patterns are possible, but more focused information on fish movements will be needed for effective implementation. Fortunately, several recent improvements in conventional fishery management and reporting will likely enhance our ability to evaluate spatial and non-spatial management options in the near future, particularly as pertaining to bycatch species.

Sign in / Sign up

Export Citation Format

Share Document