Action Research in Tropical Tuna Purse Seine Fisheries: Thoughts and Perspectives

2020 ◽  
pp. 193-212
Author(s):  
Manon Airaud ◽  
Laurent Tezenas ◽  
Gala Moreno ◽  
Laurent Dagorn ◽  
Jefferson Murua
Keyword(s):  
Action Research ◽  
Purse Seine ◽  
Tropical Tuna

scholarly journals Quantifying the increase in fishing efficiency due to the use of drifting FADs equipped with echosounders in tropical tuna purse seine fisheries

2020 ◽  
Author(s):  
Gwenaëlle Wain ◽  
Loreleï Guéry ◽  
David Michael Kaplan ◽  
Daniel Gaertner
Keyword(s):  
New Technology ◽  
Recent Change ◽  
Purse Seine ◽  
Catch Per Unit Effort ◽  
Katsuwonus Pelamis ◽  
Thunnus Obesus ◽  
Efficiency Increase ◽  
Tropical Tuna ◽  
Floating Objects ◽  
The Impact

Abstract Numerous pelagic species are known to associate with floating objects (FOBs), including tropical tunas. Purse seiners use this behaviour to facilitate the capture of tropical tunas by deploying artificial drifting fish aggregating devices (dFADs). One major recent change has been the integration of echosounders in satellite-tracked GPS buoys attached to FOBs, allowing fishers to remotely estimate fishable biomass. Understanding the effects of this new technology on catch of the three main tuna species (yellowfin tuna, Thunnus albacares; bigeye tuna, Thunnus obesus; and skipjack tuna, Katsuwonus pelamis) is important to accurately correct for this change in catch-per-unit-effort (CPUE) indices used for stock assessments. We analysed catch data from the French purse seine fleet for the period 2010–2017 in the Indian Ocean to assess the impact of this fleet’s switch to echosounder buoys around 2012. Results indicate that echosounders do not increase the probability a set will be succesful, but they have a positive effect on catch per set, with catches on average increasing by ≈2−2.5 tonnes per set (≈10%) when made on the vessel's own dFADs equipped with an echosounder buoy. Increases were due to a decrease in sets below ≈25 tonnes and an increase in those greater than ≈25 tonnes, with a non-linear transition around this threshold. This increase explains the considerable investment of purse seiners in echosounder buoys, but also raises concerns about bias in stock size estimates based on CPUE if we do not correct for this fishing efficiency increase.

Fishing on floating objects (FOBs): how French tropical tuna purse seiners split fishing effort between GPS-monitored and unmonitored FOBs

2018 ◽  
Vol 75 (11) ◽  
pp. 1849-1858 ◽  
Author(s):  
Julia E. Snouck-Hurgronje ◽  
David M. Kaplan ◽  
Emmanuel Chassot ◽  
Alexandra Maufroy ◽  
Daniel Gaertner
Keyword(s):  
Search Time ◽  
Fishing Effort ◽  
Purse Seine ◽  
Trajectory Data ◽  
Catch Per Unit Effort ◽  
Position Information ◽  
Foreign Objects ◽  
Tropical Tuna ◽  
Floating Objects ◽  
Over Time

Fishing on floating objects (FOBs) dominates catch in tropical tuna purse seine fisheries. One frequently cited advantage of deploying GPS-monitored FOBs is that the position information can be used for directed fishing to reduce search time for tuna. However, purse seiners also fish on foreign objects for which position information is not available. It is critical to quantify the prevalence of fishing on GPS-monitored versus unmonitored FOBs to understand how they impact fishing effort and catch per unit effort. We analyzed French commercial, observer, and FOB trajectory data in the Atlantic and Indian oceans to determine how often purse seine vessels fish on GPS-monitored FOBs. Only 2.7%–20.4% of French FOB fishing sets over 2007–2013 in both oceans were made on GPS-monitored FOBs. Though increasing over time, the low percentage suggests that French vessels do not primarily use GPS-monitored FOBs to reduce search time for tuna. We hypothesize that fishery-wide FOB deployments have important collective consequences for overall fishing effort and recommend that future effort metrics should be based on fishery-wide FOB activities.

scholarly journals Increasing the economic value of the eastern Pacific Ocean tropical tuna fishery: Tradeoffs between longline and purse-seine fishing

2019 ◽  
Vol 169-170 ◽  
pp. 104621 ◽  
Author(s):  
Chin-Hwa Sun (Jenny) ◽  
Mark N. Maunder ◽  
Minling Pan ◽  
Alexandre Aires-da-Silva ◽  
William H. Bayliff ◽  
...  
Keyword(s):  
Pacific Ocean ◽  
Economic Value ◽  
Eastern Pacific ◽  
Purse Seine ◽  
Eastern Pacific Ocean ◽  
Tropical Tuna ◽  
Tuna Fishery

scholarly journals Post-release survival of juvenile silky sharks captured in a tropical tuna purse seine fishery

2015 ◽  
Vol 521 ◽  
pp. 143-154 ◽  
Author(s):  
MR Hutchinson ◽  
DG Itano ◽  
JA Muir ◽  
KN Holland
Keyword(s):  
Purse Seine ◽  
Tropical Tuna ◽  
Purse Seine Fishery

scholarly journals Precision in bycatch estimates: the case of tuna purse-seine fisheries in the Indian Ocean

2012 ◽  
Vol 69 (8) ◽  
pp. 1501-1510 ◽  
Author(s):  
Monin J. Amandè ◽  
Emmanuel Chassot ◽  
Pierre Chavance ◽  
Hilario Murua ◽  
Alicia Delgado de Molina ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Linear Models ◽  
Purse Seine ◽  
Reliable Estimate ◽  
Routine Practice ◽  
Marine Animals ◽  
Trade Offs ◽  
The Indian Ocean ◽  
Current Sampling ◽  
Tropical Tuna

Abstract Amandè, M. J., Chassot, E., Chavance, P., Murua, H., Delgado de Molina, A., and Bez, N. 2012. Precision in bycatch estimates: the case of tuna purse-seine fisheries in the Indian Ocean. – ICES Journal of Marine Science, 69: . Estimating bycatch, i.e. the incidental catch of non-target marine animals and undersized individuals of target species, by raising observer data to the whole fishery is routine practice. The annual bycatch of the European tropical tuna purse-seine fishery over the period 2003–2009 was estimated at 11 590 t [95% confidence interval: (8165–15 818 t)], corresponding to 4.7% of the tuna landings. An analysis of the variability in the precision of this estimate, based on generalized linear models and Monte Carlo simulations, showed that the current sampling coverage of the tropical tuna fishery observer programme, which is 4.6% of the fishing trips, resulted in large uncertainties in bycatch estimates by species, i.e. none of the estimates have a relative root mean square error smaller than 50%. Although the overall magnitude of bycatch of the fishery appeared to be small, the current sampling coverage was insufficient to give any reliable estimate for low-occurring species, such as marine turtles, some oceanic pelagic sharks, and some billfishes. Increasing the sampling coverage would likely improve bycatch estimates. Simulation outputs were produced to help define (i) trade-offs between the priority species to be monitored, (ii) the estimation precision, (iii) expected accuracy, and (iv) the associated sampling costs.

Size-selective catch in tropical tuna purse seine fishery in the Eastern Indian Ocean: Assessment on new selectivity model for purse seine net

2016 ◽  
Vol 82 (3) ◽  
pp. 391-404 ◽  
Author(s):  
Watcharapong Chumchuen ◽  
Tatsuro Matsuoka ◽  
Kazuhiko Anraku ◽  
Sukchai Arnupapboon
Keyword(s):  
Indian Ocean ◽  
Purse Seine ◽  
Eastern Indian Ocean ◽  
Selectivity Model ◽  
Tropical Tuna ◽  
Purse Seine Fishery

scholarly journals Predicting bycatch hotspots in tropical tuna purse seine fisheries at the basin scale

2020 ◽  
Vol 24 ◽  
pp. e01393
Author(s):  
Laura Mannocci ◽  
Fabien Forget ◽  
Mariana Travassos Tolotti ◽  
Pascal Bach ◽  
Nicolas Bez ◽  
...  
Keyword(s):  
Purse Seine ◽  
Basin Scale ◽  
Tropical Tuna

Effects of time-area closure on tropical tuna purse-seine fleet dynamics through some fishery indicators

2011 ◽  
Vol 24 (4) ◽  
pp. 337-350 ◽  
Author(s):  
Edgar Torres-Irineo ◽  
Daniel Gaertner ◽  
Alicia Delgado de Molina ◽  
Javier Ariz
Keyword(s):  
Purse Seine ◽  
Tropical Tuna ◽  
Fleet Dynamics

Monitoring of Spanish flagged purse seine fishery targeting tropical tuna in the Indian ocean: Timeline and history

Marine Policy ◽  
2020 ◽  
Vol 119 ◽  
pp. 104094
Author(s):  
José Carlos Báez ◽  
María Lourdes Ramos ◽  
Miguel Herrera ◽  
Hilario Murua ◽  
José Luis Cort ◽  
...  
Keyword(s):  
Indian Ocean ◽  
Purse Seine ◽  
The Indian Ocean ◽  
Tropical Tuna ◽  
Purse Seine Fishery
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