Vertical movements, behavior, and habitat of bigeye tuna (Thunnus obesus) in the equatorial central Pacific Ocean

Fuller, Daniel W.; Schaefer, Kurt M.; Hampton, John; Caillot, Sylvain; Leroy, Bruno; Itano, David

doi:10.1016/j.fishres.2015.06.024

Cited by 30 publications

(22 citation statements)

References 38 publications

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“…The echo-sounder buoys used in this study provide a single biomass value without determining the species or size composition of the fish underneath the DFAD. Tuna are well known to engage in both horizontal and vertical movements around DFADs [51, 56–58] and, although overlap may exist in the vertical range of the three species of tuna, tagging data suggest differences in depth preferences between the species and the different sizes of these species. Skipjack tuna schools tend to remain in shallower waters, as do small yellowfin and bigeye tuna that are found occupying similar depth ranges as skipjack.…”

Section: Discussionmentioning

confidence: 99%

“…In addition to this segregation by species and sizes, the vertical distribution of tuna at DFADs may vary depending on different factors, including oceanographic conditions (e.g. thermocline depth or surface and subsurface currents) [51, 56], total associated fish biomass or number and size of species present at DFADs [36]. Recent acoustic research [59] has found a different frequency response for skipjack compared to bigeye and yellowfin tuna when analyzed simultaneously using multiple acoustic frequencies, based on anatomical differences (i.e.…”

Section: Discussionmentioning

confidence: 99%

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Aggregation process of drifting fish aggregating devices (DFADs) in the Western Indian Ocean: Who arrives first, tuna or non-tuna species?

et al. 2019

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Floating objects drifting in the surface of tropical waters, also known as drifting fish aggregating devices (DFADs), attract hundreds of marine species, including tuna and non-tuna species. Industrial tropical purse seiners have been increasingly deploying artificial man-made DFADs equipped with satellite linked echo-sounder buoys, which provide fishers with information on the accurate geo-location of the object and rough estimates of the biomass aggregated underneath, to facilitate the catch of tuna. Although several hypotheses are under consideration to explain the aggregation and retention processes of pelagic species around DFADs, the reasons driving this associative behavior are uncertain. This study uses information from 962 echo-sounder buoys attached to virgin (i.e. newly deployed) DFADs deployed in the Western Indian Ocean between 2012 and 2015 by the Spanish fleet (42,322 days observations) to determine the first detection day of tuna and non-tuna species at DFAD and to model the aggregation processes of both species group using Generalize Additive Mixed Models. Moreover, different seasons, areas and depths of the DFAD underwater structure were considered in the analysis to account for potential spatio-temporal and structure differences. Results show that tuna species arrive at DFADs before non-tuna species (13.5±8.4 and 21.7±15.1 days, respectively), and provide evidence of the significant relationship between DFAD depth and detection time for tuna, suggesting faster tuna colonization in deeper objects. For non-tuna species, this relationship appeared to be not significant. The study also reveals both seasonal and spatial differences in the aggregation patterns for different species groups, suggesting that tuna and non-tuna species may have different aggregative behaviors depending on the spatio-temporal dynamic of DFADs. This work will contribute to the understanding of the fine and mesoscale ecology and behavior of target and non-target species around DFADs and will assist managers on the sustainability of exploited resources, helping to design spatio-temporal conservation management measures for tuna and non-tuna species.

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Section: Discussionmentioning

confidence: 99%

Section: Discussionmentioning

confidence: 99%

Aggregation process of drifting fish aggregating devices (DFADs) in the Western Indian Ocean: Who arrives first, tuna or non-tuna species?

et al. 2019

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“…In pelagic predators, such as bigeye tuna (Thunnus obesus) DVM represents a form of commuting, or central place foraging, where either the animals are only able to forage efficiently in the colder deeper waters during daylight and consequently return to the warmer surface water during the night, or alternatively, follow vertically migrating prey (Vaske et al 2012). The ecological and physiological drivers for this behaviour are well understood in predators such as T. obesus (Schaefer and Fuller 2010, Fuller et al 2015, Humphries et al 2016a. Consequently, the purpose of the work presented here was to investigate the occurrence of the DVM events that most closely suggest central place foraging, to test the hypotheses that the movements are benthic rather than pelagic, that the purpose of the events is foraging and to explore possible drivers and motivations for a behaviour that must incur a metabolic cost of transport, yet reduces foraging time.…”

Section: Seasonality Of Eventsmentioning

confidence: 99%

“…A common example is nesting sea birds, such as northern gannets, Morus bassanus or black browed albatross, Diomedes melanophrys, where provisioning birds need safe terrestrial locations for nesting, yet often forage in open seas at long distances from the colony (Weimerskirch et al 1997, Patrick et al 2014. In other cases, foraging areas can only be visited temporarily, as is the case with air breathing marine predators such as seals (Burns et al 2008) or penguins (Wilson et al 1993) or in ectothermic predators such as bigeye tuna, Thunnus obesus, diving into cold waters below the thermocline (Fuller et al 2015, Humphries et al 2016a). For many animals, for example Cape fur seals, Arctocephalus pusillus pusillus (De Vos et al 2015) it is predation risk that affects foraging behaviour.…”

Section: Nektobenthic Dvm As Possible Central Place Foragingmentioning

confidence: 99%

Diel vertical migration and central place foraging in benthic predators

Humphries¹,

Simpson²,

Sims³

2017

Mar. Ecol. Prog. Ser.

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Diel vertical migration (DVM) is a widespread behaviour among many pelagic species, from zooplankton to sharks, and has been widely studied in both marine and freshwater environments.Usually, DVM comprises repeated daily vertical movements through the water column, from shallower at night to deeper during the day. Consequently DVM is perhaps unexpected in benthic predators, nonetheless, DVM has been observed in benthic sharks and freshwater teleosts, where it comprises inshore-offshore migrations over the substrate. However there is no clear evidence of this behaviour in large temperate benthic predators, such as skates. Here we present new observations of DVM in 4 species of skate (Raja brachyura, R. clavata, R. microocellata and R. montagui) that identify it as a general behaviour in this clade. Analysis of 89 depth recording archival tags yielded 674 clear DVM events where skate left daytime deeper waters for shallower night time areas before returning to within 2.5 m of starting depths. Interestingly, these events closely resemble those of central place foragers, where shallow areas are foraging and deeper areas are refuging locations.Behaviour such as this has not been previously recorded in marine benthic predators and the findings suggest DVM might occur in many other benthic species. A broader understanding of DVM in benthic animals will be important in the design of effective boundaries for marine protected DVM In benthic predators 2 areas. These findings also have implications for trophic coupling between deep and shallow benthic zones. Further characteristics of this unexpected behaviour are presented and hypotheses for its occurrence are discussed.

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“…Many exploited marine species such as billfish, tuna, sharks, and rays that spend time in ABNJ regularly undertake extensive horizontal movements and deep-dives into the meso-and even bathypelagic (1,000-4,000 m) realms (Thorrold et al, 2014;Abascal et al, 2015;Fuller et al, 2015;Howey et al, 2016). Their roles in biogeochemical cycles are largely unquantified, but the movements link surface waters and the deep ocean and are likely to influence habitat characteristics in a similar manner to whales and mesopelagic fish.…”

Section: Habitats As a Function Of Their Inhabitantsmentioning

confidence: 99%

The Structuring Role of Marine Life in Open Ocean Habitat: Importance to International Policy

O‘Leary

Roberts

2017

Front. Mar. Sci.

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Vertical movements, behavior, and habitat of bigeye tuna (Thunnus obesus) in the equatorial central Pacific Ocean

Cited by 30 publications

References 38 publications

Aggregation process of drifting fish aggregating devices (DFADs) in the Western Indian Ocean: Who arrives first, tuna or non-tuna species?

Aggregation process of drifting fish aggregating devices (DFADs) in the Western Indian Ocean: Who arrives first, tuna or non-tuna species?

Diel vertical migration and central place foraging in benthic predators

The Structuring Role of Marine Life in Open Ocean Habitat: Importance to International Policy

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