Lessons learned from implementing three, large-scale tuna tagging programmes in the western and central Pacific Ocean

Leroy, Bruno; Nicol, Simon; Lewis, Antony; Hampton, John; Kolody, Dale; Caillot, Sylvain; Hoyle, Simon

doi:10.1016/j.fishres.2013.09.001

Cited by 32 publications

(21 citation statements)

References 15 publications

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“…An extensive international publicity campaign intended to inform captains and crews of purse-seine and longline vessels, cannery managers and workers, unloaders of purse-seine vessels, and observers monitoring longline vessel transhipments about the tagging project and subsequent rewards for the return of tags was established through the Pacific Tuna Tagging Program (Leroy et al, 2013) well in advance of this project. The reward for the return of each DT was US$10, or US$15 beginning in late 2011 in Manta, Ecuador, when fish with tags intact were presented by finders to the tag recovery officer (TRO) the same day recovered, along with reliable information on the vessel and well in which the tagged fish was found.…”

Section: Dart Tagsmentioning

confidence: 99%

Movements, dispersion, and mixing of bigeye tuna (Thunnus obesus) tagged and released in the equatorial Central Pacific Ocean, with conventional and archival tags

et al. 2015

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a b s t r a c tA total of 31,242 bigeye tuna was captured, tagged, and released, 30,793 with dart tags (DTs) and 449 with geolocating archival tags (ATs), in the equatorial central Pacific Ocean along the 140• W, 155• W, 170• W, and 180• meridians, during 2008 through 2012, of which 10,029 (32.1%) of the DTs and 74 (16.5%) of the ATs were returned. A subset of high-confidence filtered DT data was retained for 5807 fish at liberty for 30 d or more, for evaluating linear displacements from release to recapture positions. For the filtered DT data, days at liberty ranged from 30 to 1701 d (median = 187 d). Linear displacements ranged from 1 to 5372 nautical miles (M) (median = 936 M), with 71% eastward and 29% westward, and 95% within 3614 M of their release positions. The data indicate significant differences in the linear displacements by release locations, days at liberty, and fish length at release. An unscented Kalman filter model with sea-surface temperature measurements integrated (UKFsst) was used to process 48 AT data sets from bigeye tuna at liberty for 30 d or longer, to obtain most probable tracks, improved estimates of geographic positions, and movement parameters. The 95% volume contours surrounding the position estimates, along the most probable tracks from bigeye tuna releases along the 140• W, 155• W, 170• W, and 180• meridians show substantial overlap. For the pooled AT data sets, the median parameter estimates from the UKFsst model for errors in longitude ( x ) and latitude ( y ) were 0.52• and 1.75• , for directed eastward and northward movements (u and v) were −2.01 M/d and −1.41 M/d, and for dispersive movement (D) was 496.7 M 2 /d. The linear displacements and most probable tracks obtained from these tagging data demonstrate constrained latitudinal dispersion, some regional fidelity, some extensive eastward longitudinal dispersion, and substantial mixing of bigeye tuna between release longitudes. The amount of mixing of bigeye tuna among these release areas in the equatorial central Pacific Ocean, with those in adjacent areas of the equatorial eastern and western Pacific Ocean, is dependent on distances between areas, with, in general, the greatest mixing occurring between the areas that are closest to one another.

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Section: Dart Tagsmentioning

confidence: 99%

Movements, dispersion, and mixing of bigeye tuna (Thunnus obesus) tagged and released in the equatorial Central Pacific Ocean, with conventional and archival tags

et al. 2015

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“…SKJ can perform extensive migrations. Large-scale tuna tagging programs conducted in the Eastern Pacific Ocean (e.g., Fink and Bayliff, 1970), Western Central Pacific Ocean (Kleiber et al, 1987;Hampton, 1997;Leroy et al, 2009Leroy et al, , 2015 and IO (Murua et al, 2015) showed that on average, SKJ undertake horizontal migrations of more than 1,000 nautical miles (Fonteneau and Hallier, 2015). However, compared to other tuna species, their vertical movements are limited and restricted to surface waters.…”

Section: Introductionmentioning

confidence: 99%

Skipjack Tuna Availability for Purse Seine Fisheries Is Driven by Suitable Feeding Habitat Dynamics in the Atlantic and Indian Oceans

et al. 2017

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An Ecological Niche model was developed for skipjack tuna (Katsuwonus pelamis, SKJ) in the Eastern Central Atlantic Ocean (AO) and Western Indian Ocean (IO) using an extensive set of presence data collected by the European purse seine fleet (1998)(1999)(2000)(2001)(2002)(2003)(2004)(2005)(2006)(2007)(2008)(2009)(2010)(2011)(2012)(2013)(2014).Chlorophyll-a fronts were used as proxy for food availability while mixed layer depth, sea surface temperature, dissolved oxygen, salinity, current intensity, and height anomaly variables were selected to describe SKJ's abiotic environmental preferences. The resultant ecological niche included both mesoscale eddy-type productive features that displayed latitudinal range in the IO to large scale upwelling systems that shrink and swell seasonally in the AO. Overall, 83% of all free swimming school sets (FSC) and 75% of drifting fish aggregating device sets (dFAD) that contained SKJ occurred within 25 km of favorable feeding habitat. In the AO, 34% of dFAD sets were made more than 100 km away from this habitat, mostly in the surface chlorophyll-a poor environment of the Guinea Current. These distant sets represent 10% of dFAD sets in the IO and 8% of all FSC sets. Our results suggest that the Mozambique Channel in the IO, with its simultaneously favorable feeding and spawning conditions, may seasonally offer a better SKJ nursery habitat than the Guinea Current which shows a substantially poorer feeding capacity. With the exception of this latter area, our results also suggest that fishing accessibility will be higher in months where the size of the favorable feeding habitats are reduced, likely because this reduction drives a geographical contraction in SKJ populations. The observed relationship between the annual size of favorable feeding habitat and both annual catch rates and total catches in the IO is consistent with the near-full exploitation of this stock that has occurred since the 2000s. Moreover, it suggests that annual habitat size could be used as an indicator of growth capacity for this highly productive stock. Habitat monitoring, as part of a dynamic fisheries management approach, should contribute to the sustainable exploitation of SKJ by providing information on the climate-dependent aspects of stock variability and the effects of dFAD deployment in food-rich habitats.

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“…The need for greater understanding of skipjack tuna movements in the WCPO, and potential for new assessment region definitions or protected areas, has been identified as a critical area of improvement for stock assessment in the WCPO (Evans et al, 2015;Kiyofuji and Ochi, 2016;PTTP, 2015), and other regions (Fonteneau, 2015;Kaplan et al, 2014). Given the expense in undertaking tagging studies, and the uncertainty present in the resulting data (Leroy et al, 2013a), use of simulation models to examine differing scenarios would appear to be a useful tool in the optimisation of such tagging experiments. This could take form of providing independent prior values for stock assessment model parameter estimation, or providing movement input to alternative operating models in management strategy evaluations.…”

Section: Fisheries Applications and Further Developmentmentioning

confidence: 99%

“…This could take form of providing independent prior values for stock assessment model parameter estimation, or providing movement input to alternative operating models in management strategy evaluations. Such tuna tagging programmes are designed to obtain information on not only movement, but also mortality and fleet-specific catch rates (Leroy et al, 2013a). Conventional mark-recapture tagging experiments assume that a tagged group of individual fish are representative of the wider population at some spatial scale, after fully mixing with this population after a period of time.…”

Section: Fisheries Applications and Further Developmentmentioning

confidence: 99%

“…Dagorn et al, 2000;Føre et al, 2009;Huse and Fiksen, 2010). Due to the nature of the pelagic environment, fisheries-independent surveys are usually not feasible, and much of the data obtained on wild animal populations is sampled from observations at the individual level through mark-recapture tagging, biologging, sightings, and catch sampling (Ford et al, 2013;Hare et al, 2015;Leroy et al, 2013a;Scutt Phillips et al, 2017). However, because population dynamics models typically consider large-scale ecological phenomena through mathematical abstractions of these individual-scale processes, informing such models with observations obtained at the individual level remains a challenge (Dagorn et al, 2001;Freon and Misund, 1998;Sippel et al, 2014).…”

Section: Introductionmentioning

confidence: 99%

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An individual-based model of skipjack tuna ( Katsuwonus pelamis ) movement in the tropical Pacific ocean

Phillips

Gupta

Senina

et al. 2018

Progress in Oceanography

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The distribution of marine species is often modeled using Eulerian approaches, in which changes to population density or abundance are calculated at fixed locations in space. Conversely, Lagrangian, or individual-based, models simulate the movement of individual particles moving in continuous space, with broader-scale patterns such as distribution being an emergent property of many, potentially adaptive, individuals. These models offer advantages in examining dynamics across spatiotemporal scales and making comparisons with observations from individual-scale data.Here, we introduce and describe such a model, the Individual-based Kinesis, Advection and Movement of Ocean ANimAls model (Ikamoana), which we use to replicate the movement processes of an existing Eulerian model for marine predators (the Spatial Ecosystem and Population Dynamics Model, SEAPODYM). Ikamoana simulates the movement of either individual or groups of animals by physical ocean currents, habitat-dependent stochastic movements (kinesis), and taxis movements representing active searching behaviours.Applying our model to Pacific skipjack tuna (Katsuwonus pelamis), we show that it accurately replicates the evolution of density distribution simulated by SEAPODYM with low time-mean error and a spatial correlation of density that exceeds 0.96 at all times. We demonstrate how the Lagrangian approach permits easy tracking of individuals' trajectories for examining connectivity between different regions, and show how the model can provide independent estimates of transfer rates between commonly used assessment regions. In particular, we find that retention rates in most assessment regions are considerably smaller (up to a factor of 2) than those estimated by this population of skipjack's primary assessment model. Moreover, these rates are sensitive to ocean state (e.g. El Nino vs La Nina) and so assuming fixed transfer rates between regions may lead to spurious stock estimates. A novel feature of the Lagrangian approach is that individual schools can be tracked through time, and we demonstrate that movement between two assessment regions at broad temporal scales includes extended transits through other regions at finer-scales.Finally, we discuss the utility of this modeling framework for the management of marine reserves, designing effective monitoring programmes, and exploring hypotheses regarding the behaviour of hard-to-observe oceanic animals.

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Lessons learned from implementing three, large-scale tuna tagging programmes in the western and central Pacific Ocean

Cited by 32 publications

References 15 publications

Movements, dispersion, and mixing of bigeye tuna (Thunnus obesus) tagged and released in the equatorial Central Pacific Ocean, with conventional and archival tags

Movements, dispersion, and mixing of bigeye tuna (Thunnus obesus) tagged and released in the equatorial Central Pacific Ocean, with conventional and archival tags

Skipjack Tuna Availability for Purse Seine Fisheries Is Driven by Suitable Feeding Habitat Dynamics in the Atlantic and Indian Oceans

An individual-based model of skipjack tuna ( Katsuwonus pelamis ) movement in the tropical Pacific ocean

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