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| Baidai, Yannick; Dagorn, Laurent; Gaertner, Daniel; Denebourg, Jean-louis; Duparc, Antoine; Floch, Laurent; Capello, Manuela. |
| This paper presents an associative behavior-based abundance index (ABBI) providing direct estimates of the abundance of yellowfin tuna (Thunnus albacares) based on their associative behavior around floating objects (FOBs). Considering the associative dynamics of small yellowfin tuna individuals (<10 kg) at FOBs through residence and absence times at FOBs, together with acoustic data obtained from fisher’s echosounder buoys, the ABBI index is derived for yellowfin tuna in the western Indian Ocean over the period 2013-2019. This index accounts for both the FOB-associated and free-swimming components of the tuna populations, as well as for the effects of increasing numbers of FOBs on each component. |
| Tipo: Text |
Palavras-chave: Abundance Index; Associative behavior; FADs; Yellowfin tuna. |
| Ano: 2021 |
URL: https://archimer.ifremer.fr/doc/00693/80507/83718.pdf |
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| Véras, Luísa Queiroz; Capello, Manuela; Forget, Fabien; Tolotti, Mariana Travassos; Véras, Drausio Pinheiro; Dagorn, Laurent; Hazin, Fábio Hissa. |
| Catches of pelagic fish associated to anchored Fish Aggregating Devices have been responsible for increases in income, fish consumption, and even cultural identity of artisanal fishing communities in many developing countries worldwide. Nonetheless, in Brazil, aFAD fishing is still poorly developed and studied. In this experiment, FADs were anchored offshore the city of Recife (Northeastern Brazil) to investigate the potential of moored buoys in the aggregation of commercially important pelagic species near the coast, as an alternative fishing site for artisanal fishers. The behavior of acoustically tagged fish was investigated to assess whether they were attracted to the FADs and how long they remained associated to them. The results indicated that,... |
| Tipo: Text |
Palavras-chave: Associative behavior; Acoustic tagging; Moored FADs; Pelagic fish; Artisanal fishing. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00665/77751/79875.pdf |
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| Tolotti, Mariana Travassos; Forget, Fabien; Capello, Manuela; Filmalter, John David; Hutchinson, Melanie; Itano, David; Holland, Kim; Dagorn, Laurent. |
| Several pelagic fish species are known to regularly associate with floating objects in the open ocean, including commercially valuable species. The tuna purse seine industry takes advantage of this associative behavior and has been increasingly deploying free-drifting man-made floating objects, also known as fish aggregating devices (FADs). Using passive acoustic telemetry, this study describes the associative dynamics of the main targeted tropical tuna species (Thunnus albacares, T. obesus and Katsuwonus pelamis), as well as three major bycatch species, silky shark (Carcharhinus falciformis), rainbow runner (Elagatis bipinnulata) and oceanic triggerfish (Canthidermis maculata). Short-term excursions away from the FADs were frequently performed by all tuna... |
| Tipo: Text |
Palavras-chave: Behavior; Acoustic telemetry; Residence time; Floating objects; Pelagic fish; Tropical tuna. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00609/72077/71042.pdf |
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| Capello, Manuela; Robert, Marianne; Soria, Marc; Potin, Gael; Itano, David; Holland, Kim; Deneubourg, Jean-louis; Dagorn, Laurent. |
| The rapid expansion of the use of passive acoustic telemetry technologies has facilitated unprecedented opportunities for studying the behavior of marine organisms in their natural environment. This technological advance would greatly benefit from the parallel development of dedicated methodologies accounting for the variety of timescales involved in the remote detection of tagged animals related to instrumental, environmental and behavioral events. In this paper we propose a methodological framework for estimating the site fidelity (“residence times”) of acoustic tagged animals at different timescales, based on the survival analysis of continuous residence times recorded at multiple receivers. Our approach is validated through modeling and applied on two... |
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| Ano: 2015 |
URL: https://archimer.ifremer.fr/doc/00275/38589/37116.pdf |
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| Pérez, Geraldine; Dagorn, Laurent; Deneubourg, Jean-louis; Forget, Fabien; Filmalter, John D.; Holland, Kim; Itano, David; Adam, Shiham; Jauharee, Riyaz; Beeharry, Sunil P.; Capello, Manuela. |
| Background Aggregation sites represent important sources of environmental heterogeneity and can modify the movement behavior of animals. When these sites are artificially established through anthropogenic actions, the consequent alterations to animal movements may impact their ecology with potential implications for their fitness. Floating objects represent important sources of habitat heterogeneity for tropical tunas, beneath which these species naturally aggregate in large numbers. Man-made floating objects, called Fish Aggregating Devices (FAD), are used by fishers on a massive scale to facilitate fishing operations. In addition to the direct impacts that fishing with FADs has on tuna populations, assessing the effects of increasing the numbers of FADs... |
| Tipo: Text |
Palavras-chave: Acoustic tagging; Associative behavior; Density of floating objects; Movement behavior; Tropical tuna. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00659/77137/78454.pdf |
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| Forget, Fabien; Cowley, Paul; Capello, Manuela; Filmalter, John D.; Dagorn, Laurent. |
| Multispecies aggregations at floating objects are a common feature throughout the world's tropical and subtropical oceans. The evolutionary benefits driving this associative behaviour of pelagic fish remains unclear and information on the associative behaviour of non-tuna species remains scarce. This study investigated the associative behaviour of oceanic triggerfish (Canthidermis maculata) and rainbow runner (Elagatis bipinnulata), two major bycatch species in the tropical tuna purse seine fishery, at floating objects in the western Indian Ocean. A total of 24 rainbow runner and 46 oceanic triggerfish were tagged with acoustic transmitters at nine drifting FADs equipped with satellite linked receivers. Both species remained associated with the same... |
| Tipo: Text |
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| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00624/73626/73053.pdf |
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| Baidai, Y; Dagorn, Laurent; Amande, Mj; Gaertner, Daniel; Capello, Manuela. |
| The aggregative behavior of tuna around floating object is widely exploited by the industrial purse-seine fishery, which deploy thousands of floating objects each year in all oceans in order to improve their catches. These fish aggregating devices (FADs) are generally equipped with echosounder buoys that can collect acoustic data, conferring to these devices the status of privileged observation platforms for the fish communities that aggregate. Using a classification model based on supervised learning algorithms trained on M3I buoy data, we were able to translate the acoustic data collected along the trajectories of 5748 drifting FADs newly deployed between 2016 and 2018 in the Indian Ocean into presence or absence of tuna aggregation. Analysis of the... |
| Tipo: Text |
Palavras-chave: Echosounders; Drifting fish aggregating devices (FAD); Tropical tunas; Behaviour. |
| Ano: 2019 |
URL: https://archimer.ifremer.fr/doc/00615/72694/71700.pdf |
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| Mannocci, Laura; Forget, Fabien; Travassos Tolotti, Mariana; Bach, Pascal; Bez, Nicolas; Demarcq, Herve; Kaplan, David; Sabarros, Philippe; Simier, Monique; Capello, Manuela; Dagorn, Laurent. |
| Fisheries observer programs represent the most reliable way to collect data on fisheries bycatch. However, their limited coverage leads to important data gaps that preclude bycatch mitigation at the basin scale. Habitat models developed from available fisheries observer programs offer a potential solution to fill these data gaps. We focus on tropical tuna purse seine fisheries (TTPSF) that span across the tropics and extensively rely on floating objects (FOBs) for catching tuna schools, leading to the bycatch of other species associated with these objects. Bycatch under floating objects is dominated by five species, including the vulnerable silky shark Carcharhinus falciformis and four bony fishes (oceanic triggerfish Canthidermis maculata, rainbow runner... |
| Tipo: Text |
Palavras-chave: Bycatch; Habitat modelling; Hotspots; Fisheries observer programs; Geographical extrapolation; Tropical oceans. |
| Ano: 2020 |
URL: https://archimer.ifremer.fr/doc/00662/77385/78986.pdf |
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