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137 results on '"Dagorn L"'

1. The heterogeneous spatial and temporal patterns of behavior of small pelagic fish in an array of Fish Aggregating Devices (FADs)

Author

Capello, M., Soria, M., Cotel, P., Potin, G., Dagorn, L., and Fréon, P.

Subjects
Quantitative Biology - Populations and Evolution
Abstract

Identifying spatial and temporal patterns can reveal the driving factors that govern the behavior of fish in their environment. In this study, we characterized the spatial and temporal occupation of 37 acoustically tagged bigeye scads (Selar Crumenophthalmus) in an array of shallow Fish Aggregating Devices (FADs) to clarify the mechanism that leads fish to associate with FADs. A comparison of the number of visits and residence times exhibited by the fish at different FADs revealed a strong variability over the array of FADS, with the emergence of a leading FAD, which recorded the majority of visits and retained the fish for a longer period of time. We found diel variability in the residence times, with fish associated at daytime and exploring the array of FADs at nighttime. We demonstrated that this diel temporal pattern was amplified in the leading FAD. We identified a 24-hour periodicity for a subset of individuals aggregated to the leading FAD, thus suggesting that those fish were able to find this FAD after night excursions. The modeling of fish movements based on a Monte Carlo sampling of inter-FAD transitions revealed that the observed spatial heterogeneity in the number of visits could not be explained through simple array-connectivity arguments. Similarly, we demonstrated that the high residence times recorded at the leading FAD were not due to the spatial arrangement of individual fish having different associative characters. We discussed the relationships between these patterns of association with the FADs, the exploration of the FAD array and the possible effects of social interactions and environmental factors., Comment: 21 pages, 9 figures + 2 supplementary figures

Published
2012

2. Role of current and daylight variations on small-pelagic fish aggregations around a coastal FAD from accurate acoustic tracking

Author

Capello, M., Soria, M., Potin, G., Cotel, P., and Dagorn, L.

Subjects
Quantitative Biology - Populations and Evolution
Abstract

We monitored twelve acoustically-tagged small pelagic fish (Selar crumenophthalmus) around a floating object in shallow water, playing the role of a coastal fish aggregating device (FAD). We characterized the response of the tagged-fish aggregation to varying current strengths and daylight. We found that the current induced a displacement of the aggregation upstream of the FAD, at distances that were increasing with the current strength. We gave evidence, of an expansion and a higher coordination in the aggregation at dusk, with increasing swimming speed, distances among congeners and alignment. We discussed possible scenarios where fish polarization increases at dusk and proposed complementary measurements in future experiments that could confirm our findings., Comment: 16 pages, 5 figures

Published
2012

5. Is FAD fishing an economic trap? Effects of seasonal closures and other management measures on a purse‐seine tuna fleet.

Author

Guillotreau, P., Salladarré, F., Capello, M., Dupaix, A., Floc'h, L., Tidd, A., Tolotti, M., and Dagorn, L.

Subjects
FISH traps, MACHINE learning, BIGEYE tuna, YELLOWFIN tuna, TUNA, SCHOOL closings, MARINE parks & reserves
Abstract

The management of fish aggregating devices (FAD) creates heated debates in tuna fishery management organizations striving to reduce the number of deployed floating objects. Through several econometric models and a machine learning approach, we evaluate the consequences of three management scenarios on the catch and profit of the French purse‐seine fleet operating in the Indian Ocean: (1) a half reduction in the number of authorized buoys per vessel, (2) a 72‐day closure of FAD fishing with and (3) without re‐allocation of effort on free schools. The results show a significant decrease of fleet profits by 7%, 10% and 18% respectively. We hypothesize an "economic trap" of FAD fishing caused by the far greater efficiency of this harvesting technique for larger vessels searching for economies of scale, and by the overfished status and catch limitation of yellowfin (Thunnus albacares) and bigeye (Thunnus obesus) tunas in the Indian Ocean. The results are compared with other studies looking at the impact of FAD management measures in other oceans. [ABSTRACT FROM AUTHOR]

Published
2024
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6. Diving into the vertical dimension of elasmobranch movement ecology

Author

Andrzejaczek, S., Lucas, T.C.D., Goodman, M.C., Hussey, N.E., Armstrong, A.J., Carlisle, A., Coffey, D.M., Gleiss, A.C., Huveneers, C., Jacoby, D.M.P., Meekan, M.G., Mourier, J., Peel, L.R., Abrantes, K., Afonso, A.S., Ajemian, M.J., Anderson, B.N., Anderson, S.D., Araujo, G., Armstrong, A.O., Bach, P., Barnett, A., Bennett, M.B., Bezerra, N.A., Bonfil, R., Boustany, A.M., Bowlby, H.D., Branco, I., Braun, C.D., Brooks, E.J., Brown, J., Burke, P.J., Butcher, P., Castleton, M., Chapple, T.K., Chateau, O., Clarke, M., Coelho, R., Cortés, E., Couturier, L.I.E., Cowley, P.D., Croll, D.A., Cuevas, J.M., Curtis, T.H., Dagorn, L., Dale, J.J., Daly, R., Dewar, H., Doherty, P.D., Domingo, A., Dove, A.D.M., Drew, M., Dudgeon, C.L., Duffy, C.A.J., Elliott, R.G., Ellis, J.R., Erdmann, M.V., Farrugia, T.J., Ferreira, L.C., Ferretti, F., Filmalter, J.D., Finucci, B., Fischer, C., Fitzpatrick, R., Forget, F., Forsberg, K., Francis, M.P., Franks, B.R., Gallagher, A.J., Galván-Magaña, F., García, M.L., Gaston, T.F., Gillanders, B.M., Gollock, M.J., Green, J.R., Green, S., Griffiths, C.A., Hammerschlag, N., Hasan, A., Hawkes, L.A., Hazin, F., Heard, M., Hearn, A., Hedges, K.J., Henderson, S.M., Holdsworth, J., Holland, K.N., Howey, L.A., Hueter, R.E., Humphries, N.E., Hutchinson, M., Jaine, F.R.A., Jorgensen, S.J., Kanive, P.E., Labaja, J., Lana, F.O., Lassauce, H., Lipscombe, R.S., Llewellyn, F., Macena, B.C.L., Mambrasar, R., McAllister, J.D., McCully Phillips, S.R., McGregor, F., McMillan, M.N., McNaughton, L.M., Mendonça, S.A., Meyer, C.G., Meyers, M., Mohan, J.A., Montgomery, J.C., Mucientes, G., Musyl, M.K., Nasby-Lucas, N., Natanson, L.J., O’Sullivan, J.B., Oliveira, P., Papastamtiou, Y.P., Patterson, T.A., Pierce, S.J., Queiroz, N., Radford, C.A., Richardson, A.J., Righton, D., Rohner, C.A., Royer, M.A., Saunders, R.A., Schaber, M., Schallert, R.J., Scholl, M.C., Seitz, A.C., Semmens, J.M., Setyawan, E., Shea, B.D., Shidqi, R.A., Shillinger, G.L., Shipley, O.N., Shivji, M.S., Sianipar, A.B., Silva, J.F., Sims, D.W., Skomal, G.B., Sousa, L.L., Southall, E.J., Spaet, J.L.Y., Stehfest, K.M., Stevens, G., Stewart, J.D., Sulikowski, J.A., Syakurachman, I., Thorrold, S.R., Thums, M., Tickler, D., Tolloti, M.T., Townsend, K.A., Travassos, P., Tyminski, J.P., Vaudo, J.J., Veras, D., Wantiez, L., Weber, S.B., Wells, R.J.D., Weng, K.C., Wetherbee, B.M., Williamson, J.E., Witt, M.J., Wright, S., Zilliacus, K., Block, B.A., Curnick, D.J., Andrzejaczek, S., Lucas, T.C.D., Goodman, M.C., Hussey, N.E., Armstrong, A.J., Carlisle, A., Coffey, D.M., Gleiss, A.C., Huveneers, C., Jacoby, D.M.P., Meekan, M.G., Mourier, J., Peel, L.R., Abrantes, K., Afonso, A.S., Ajemian, M.J., Anderson, B.N., Anderson, S.D., Araujo, G., Armstrong, A.O., Bach, P., Barnett, A., Bennett, M.B., Bezerra, N.A., Bonfil, R., Boustany, A.M., Bowlby, H.D., Branco, I., Braun, C.D., Brooks, E.J., Brown, J., Burke, P.J., Butcher, P., Castleton, M., Chapple, T.K., Chateau, O., Clarke, M., Coelho, R., Cortés, E., Couturier, L.I.E., Cowley, P.D., Croll, D.A., Cuevas, J.M., Curtis, T.H., Dagorn, L., Dale, J.J., Daly, R., Dewar, H., Doherty, P.D., Domingo, A., Dove, A.D.M., Drew, M., Dudgeon, C.L., Duffy, C.A.J., Elliott, R.G., Ellis, J.R., Erdmann, M.V., Farrugia, T.J., Ferreira, L.C., Ferretti, F., Filmalter, J.D., Finucci, B., Fischer, C., Fitzpatrick, R., Forget, F., Forsberg, K., Francis, M.P., Franks, B.R., Gallagher, A.J., Galván-Magaña, F., García, M.L., Gaston, T.F., Gillanders, B.M., Gollock, M.J., Green, J.R., Green, S., Griffiths, C.A., Hammerschlag, N., Hasan, A., Hawkes, L.A., Hazin, F., Heard, M., Hearn, A., Hedges, K.J., Henderson, S.M., Holdsworth, J., Holland, K.N., Howey, L.A., Hueter, R.E., Humphries, N.E., Hutchinson, M., Jaine, F.R.A., Jorgensen, S.J., Kanive, P.E., Labaja, J., Lana, F.O., Lassauce, H., Lipscombe, R.S., Llewellyn, F., Macena, B.C.L., Mambrasar, R., McAllister, J.D., McCully Phillips, S.R., McGregor, F., McMillan, M.N., McNaughton, L.M., Mendonça, S.A., Meyer, C.G., Meyers, M., Mohan, J.A., Montgomery, J.C., Mucientes, G., Musyl, M.K., Nasby-Lucas, N., Natanson, L.J., O’Sullivan, J.B., Oliveira, P., Papastamtiou, Y.P., Patterson, T.A., Pierce, S.J., Queiroz, N., Radford, C.A., Richardson, A.J., Righton, D., Rohner, C.A., Royer, M.A., Saunders, R.A., Schaber, M., Schallert, R.J., Scholl, M.C., Seitz, A.C., Semmens, J.M., Setyawan, E., Shea, B.D., Shidqi, R.A., Shillinger, G.L., Shipley, O.N., Shivji, M.S., Sianipar, A.B., Silva, J.F., Sims, D.W., Skomal, G.B., Sousa, L.L., Southall, E.J., Spaet, J.L.Y., Stehfest, K.M., Stevens, G., Stewart, J.D., Sulikowski, J.A., Syakurachman, I., Thorrold, S.R., Thums, M., Tickler, D., Tolloti, M.T., Townsend, K.A., Travassos, P., Tyminski, J.P., Vaudo, J.J., Veras, D., Wantiez, L., Weber, S.B., Wells, R.J.D., Weng, K.C., Wetherbee, B.M., Williamson, J.E., Witt, M.J., Wright, S., Zilliacus, K., Block, B.A., and Curnick, D.J.

Abstract

Knowledge of the three-dimensional movement patterns of elasmobranchs is vital to understand their ecological roles and exposure to anthropogenic pressures. To date, comparative studies among species at global scales have mostly focused on horizontal movements. Our study addresses the knowledge gap of vertical movements by compiling the first global synthesis of vertical habitat use by elasmobranchs from data obtained by deployment of 989 biotelemetry tags on 38 elasmobranch species. Elasmobranchs displayed high intra- and interspecific variability in vertical movement patterns. Substantial vertical overlap was observed for many epipelagic elasmobranchs, indicating an increased likelihood to display spatial overlap, biologically interact, and share similar risk to anthropogenic threats that vary on a vertical gradient. We highlight the critical next steps toward incorporating vertical movement into global management and monitoring strategies for elasmobranchs, emphasizing the need to address geographic and taxonomic biases in deployments and to concurrently consider both horizontal and vertical movements.

Published
2022

7. Biodegradable DFADs: Current status and prospects

Author

Zudaire, I., Moreno, G., Murua, H., Murua, J., Tolotti, M.T., Roman, M., Hall, M., López, J., Grande, M., Merino, G., Escalle, L., Hamer, P., Basurko, O.C., Capello, M., Dagorn, L., Ramos, María Lourdes, Abascal, Francisco Javier, Báez, José Carlos, Pascual-Alayón, Pedro José, Deniz, Santiago, Santiago, J., Zudaire, I., Moreno, G., Murua, H., Murua, J., Tolotti, M.T., Roman, M., Hall, M., López, J., Grande, M., Merino, G., Escalle, L., Hamer, P., Basurko, O.C., Capello, M., Dagorn, L., Ramos, María Lourdes, Abascal, Francisco Javier, Báez, José Carlos, Pascual-Alayón, Pedro José, Deniz, Santiago, and Santiago, J.

Abstract

Until recently, dFAD structure, materials and designs have remained quite rudimentary and virtually the same since their discovery, characterized by the increase of the dimensions and prevailing heavy use of plastic components. Biodegradable materials are called to be an important part of the solution, as they can faster degrade in the environment, free of toxins and heavy metals, reducing their lifespan, and preventing them from accumulating in sensitive areas once they are abandoned, lost or discarded. During last decades, regulatory measures at tRFMOs have advanced in the gradual implementation of biodegradable materials in dFAD constructions together with other measures limiting the number of active dFADs and the use of netting materials. However, more clarity is needed starting with a standardised definition of biodegradable dFADs among tRFMOs, to provide operational guidance. Research with those natural and synthetic materials is required, along with updated data collection for monitoring standards, as well as alternative and complementary actions need to be explored to contribute to minimising dFAD adverse effects on environment. Acknowledging the current difficulties for the implementation of fully biodegradable dFADs a stepwise process towards the implementation of fully biodegradable dFADs should be considered.

Published
2022

10. Spatial behaviour and site fidelity of the sicklefin lemon shark Negaprion acutidens in a remote Indian Ocean atoll

Author

Filmalter, J.D., Dagorn, L., and Cowley, P.D.

Subjects
Animal behavior -- Research, Human mechanics -- Psychological aspects, Sharks -- Behavior, Biological sciences
Abstract

Understanding the movement behaviour of any species is important for developing species-specific management and conservation measures. In recent years, the sicklefin lemon shark Negaprion acutidens has shown rapid range reductions and has even disappeared altogether in certain areas. In this study, the area use patterns and site fidelity of the N. acutidens were assessed at the St. Joseph Atoll in the Seychelles. Passive acoustic telemetry methods were employed to monitor the movements of 19 tagged individuals for 1 year. Area use within the lagoon of the atoll was found to be highly restricted, with individuals typically utilising a small portion of the available area throughout the year. A high-use zone was apparent in the south-east of the atoll's lagoon, which was shared by many of the monitored individuals. Fidelity to the study site was found to be extremely high, with the 79 % of tagged N. acutidens still present in the atoll at the end of the study. Individuals displayed both diel and tidal movements between the lagoon and surrounding habitats. The restricted area use and high site fidelity observed in this study highlight both the vulnerability of this species to rapid over exploitation and importance of remote habitats such as the St. Joseph Atoll in their future conservation. The results obtained here can be used to inform management decisions regarding the development and utilisation of similar atoll environments throughout the species' range., Introduction The spatial ecology of elasmobranch species has received considerable research attention in recent years, largely due to concerns over their conservation status (Domeier and Nasby-Lucas 2008; Heupel et al. [...]

Published
2013
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11. Reply to: Shark mortality cannot be assessed by fishery overlap alone

Author

Queiroz, N, Humphries, NE, Couto, A, Vedor, M, da Costa, I, Sequeira, AMM, Mucientes, G, Santos, AM, Abascal, FJ, Abercrombie, DL, Abrantes, K, Acuña-Marrero, D, Afonso, AS, Afonso, P, Anders, D, Araujo, G, Arauz, R, Bach, P, Barnett, A, Bernal, D, Berumen, ML, Lion, SB, Bezerra, NPA, Blaison, AV, Block, BA, Bond, ME, Bonfil, R, Bradford, RW, Braun, CD, Brooks, EJ, Brooks, A, Brown, J, Bruce, BD, Byrne, ME, Campana, SE, Carlisle, AB, Chapman, DD, Chapple, TK, Chisholm, J, Clarke, CR, Clua, EG, Cochran, JEM, Crochelet, EC, Dagorn, L, Daly, R, Cortés, DD, Doyle, TK, Drew, M, Duffy, CAJ, Erikson, T, Espinoza, E, Ferreira, LC, Ferretti, F, Filmalter, JD, Fischer, GC, Fitzpatrick, R, Fontes, J, Forget, F, Fowler, M, Francis, MP, Gallagher, AJ, Gennari, E, Goldsworthy, SD, Gollock, MJ, Green, JR, Gustafson, JA, Guttridge, TL, Guzman, HM, Hammerschlag, N, Harman, L, Hazin, FHV, Heard, M, Hearn, AR, Holdsworth, JC, Holmes, BJ, Howey, LA, Hoyos, M, Hueter, RE, Hussey, NE, Huveneers, C, Irion, DT, Jacoby, DMP, Jewell, OJD, Johnson, R, Jordan, LKB, Joyce, W, Keating Daly, CA, Ketchum, JT, Klimley, AP, Kock, AA, Koen, P, Ladino, F, Lana, FO, Lea, JSE, Llewellyn, F, Lyon, WS, MacDonnell, A, Macena, BCL, Marshall, H, McAllister, JD, Queiroz, N, Humphries, NE, Couto, A, Vedor, M, da Costa, I, Sequeira, AMM, Mucientes, G, Santos, AM, Abascal, FJ, Abercrombie, DL, Abrantes, K, Acuña-Marrero, D, Afonso, AS, Afonso, P, Anders, D, Araujo, G, Arauz, R, Bach, P, Barnett, A, Bernal, D, Berumen, ML, Lion, SB, Bezerra, NPA, Blaison, AV, Block, BA, Bond, ME, Bonfil, R, Bradford, RW, Braun, CD, Brooks, EJ, Brooks, A, Brown, J, Bruce, BD, Byrne, ME, Campana, SE, Carlisle, AB, Chapman, DD, Chapple, TK, Chisholm, J, Clarke, CR, Clua, EG, Cochran, JEM, Crochelet, EC, Dagorn, L, Daly, R, Cortés, DD, Doyle, TK, Drew, M, Duffy, CAJ, Erikson, T, Espinoza, E, Ferreira, LC, Ferretti, F, Filmalter, JD, Fischer, GC, Fitzpatrick, R, Fontes, J, Forget, F, Fowler, M, Francis, MP, Gallagher, AJ, Gennari, E, Goldsworthy, SD, Gollock, MJ, Green, JR, Gustafson, JA, Guttridge, TL, Guzman, HM, Hammerschlag, N, Harman, L, Hazin, FHV, Heard, M, Hearn, AR, Holdsworth, JC, Holmes, BJ, Howey, LA, Hoyos, M, Hueter, RE, Hussey, NE, Huveneers, C, Irion, DT, Jacoby, DMP, Jewell, OJD, Johnson, R, Jordan, LKB, Joyce, W, Keating Daly, CA, Ketchum, JT, Klimley, AP, Kock, AA, Koen, P, Ladino, F, Lana, FO, Lea, JSE, Llewellyn, F, Lyon, WS, MacDonnell, A, Macena, BCL, Marshall, H, and McAllister, JD

Published
2021

12. Reply to: Shark mortality cannot be assessed by fishery overlap alone

Author

Queiroz, N., Humphries, N.E., Couto, A., Vedor, M., da Costa, I., Sequeira, A.M.M., Mucientes, G., Santos, A.M., Abascal, F.J., Abercrombie, D.L., Abrantes, K., Acuña-Marrero, D., Afonso, A.S., Afonso, P., Anders, D., Araujo, G., Arauz, R., Bach, P., Barnett, A., Bernal, D., Berumen, M.L., Lion, S.B., Bezerra, N.P.A., Blaison, A.V., Block, B.A., Bond, M.E., Bonfil, R., Bradford, R.W., Braun, C.D., Brooks, E.J., Brooks, A., Brown, J., Bruce, B.D., Byrne, M.E., Campana, S.E., Carlisle, A.B., Chapman, D.D., Chapple, T.K., Chisholm, J., Clarke, C.R., Clua, E.G., Cochran, J.E.M., Crochelet, E.C., Dagorn, L., Daly, R., Cortés, D.D., Doyle, T.K., Drew, M., Duffy, C.A.J., Erikson, T., Espinoza, E., Ferreira, L.C., Ferretti, F., Filmalter, J.D., Fischer, G.C., Fitzpatrick, R., Fontes, J., Forget, F., Fowler, M., Francis, M.P., Gallagher, A.J., Gennari, E., Goldsworthy, S.D., Gollock, M.J., Green, J.R., Gustafson, J.A., Guttridge, T.L., Guzman, H.M., Hammerschlag, N., Harman, L., Hazin, F.H.V., Heard, M., Hearn, A.R., Holdsworth, J.C., Holmes, B.J., Howey, L.A., Hoyos, M., Hueter, R.E., Hussey, N.E., Huveneers, C., Irion, D.T., Jacoby, D.M.P., Jewell, O.J.D., Johnson, R., Jordan, L.K.B., Joyce, W., Keating Daly, C.A., Ketchum, J.T., Klimley, A.P., Kock, A.A., Koen, P., Ladino, F., Lana, F.O., Lea, J.S.E., Llewellyn, F., Lyon, W.S., MacDonnell, A., Macena, B.C.L., Marshall, H., McAllister, J.D., Meÿer, M.A., Morris, J.J., Nelson, E.R., Papastamatiou, Y.P., Peñaherrera-Palma, C., Pierce, S.J., Poisson, F., Quintero, L.M., Richardson, A.J., Rogers, P.J., Rohner, C.A., Rowat, D.R.L., Samoilys, M., Semmens, J.M., Sheaves, M., Shillinger, G., Shivji, M., Singh, S., Skomal, G.B., Smale, M.J., Snyders, L.B., Soler, G., Soria, M., Stehfest, K.M., Thorrold, S.R., Tolotti, M.T., Towner, A., Travassos, P., Tyminski, J.P., Vandeperre, F., Vaudo, J.J., Watanabe, Y.Y., Weber, S.B., Wetherbee, B.M., White, T.D., Williams, S., Zárate, P.M., Harcourt, R., Hays, G.C., Meekan, M.G., Thums, M., Irigoien, X., Eguíluz, V.M., Duarte, C.M., Sousa, L.L., Simpson, S.J., Southall, E.J., Sims, D.W., Queiroz, N., Humphries, N.E., Couto, A., Vedor, M., da Costa, I., Sequeira, A.M.M., Mucientes, G., Santos, A.M., Abascal, F.J., Abercrombie, D.L., Abrantes, K., Acuña-Marrero, D., Afonso, A.S., Afonso, P., Anders, D., Araujo, G., Arauz, R., Bach, P., Barnett, A., Bernal, D., Berumen, M.L., Lion, S.B., Bezerra, N.P.A., Blaison, A.V., Block, B.A., Bond, M.E., Bonfil, R., Bradford, R.W., Braun, C.D., Brooks, E.J., Brooks, A., Brown, J., Bruce, B.D., Byrne, M.E., Campana, S.E., Carlisle, A.B., Chapman, D.D., Chapple, T.K., Chisholm, J., Clarke, C.R., Clua, E.G., Cochran, J.E.M., Crochelet, E.C., Dagorn, L., Daly, R., Cortés, D.D., Doyle, T.K., Drew, M., Duffy, C.A.J., Erikson, T., Espinoza, E., Ferreira, L.C., Ferretti, F., Filmalter, J.D., Fischer, G.C., Fitzpatrick, R., Fontes, J., Forget, F., Fowler, M., Francis, M.P., Gallagher, A.J., Gennari, E., Goldsworthy, S.D., Gollock, M.J., Green, J.R., Gustafson, J.A., Guttridge, T.L., Guzman, H.M., Hammerschlag, N., Harman, L., Hazin, F.H.V., Heard, M., Hearn, A.R., Holdsworth, J.C., Holmes, B.J., Howey, L.A., Hoyos, M., Hueter, R.E., Hussey, N.E., Huveneers, C., Irion, D.T., Jacoby, D.M.P., Jewell, O.J.D., Johnson, R., Jordan, L.K.B., Joyce, W., Keating Daly, C.A., Ketchum, J.T., Klimley, A.P., Kock, A.A., Koen, P., Ladino, F., Lana, F.O., Lea, J.S.E., Llewellyn, F., Lyon, W.S., MacDonnell, A., Macena, B.C.L., Marshall, H., McAllister, J.D., Meÿer, M.A., Morris, J.J., Nelson, E.R., Papastamatiou, Y.P., Peñaherrera-Palma, C., Pierce, S.J., Poisson, F., Quintero, L.M., Richardson, A.J., Rogers, P.J., Rohner, C.A., Rowat, D.R.L., Samoilys, M., Semmens, J.M., Sheaves, M., Shillinger, G., Shivji, M., Singh, S., Skomal, G.B., Smale, M.J., Snyders, L.B., Soler, G., Soria, M., Stehfest, K.M., Thorrold, S.R., Tolotti, M.T., Towner, A., Travassos, P., Tyminski, J.P., Vandeperre, F., Vaudo, J.J., Watanabe, Y.Y., Weber, S.B., Wetherbee, B.M., White, T.D., Williams, S., Zárate, P.M., Harcourt, R., Hays, G.C., Meekan, M.G., Thums, M., Irigoien, X., Eguíluz, V.M., Duarte, C.M., Sousa, L.L., Simpson, S.J., Southall, E.J., and Sims, D.W.

Published
2021

13. Reply to: Caution over the use of ecological big data for conservation

Author

Queiroz, N., Humphries, N.E., Couto, A., Vedor, M., da Costa, I., Sequeira, A.M.M., Mucientes, G., Santos, A.M., Abascal, F.J., Abercrombie, D.L., Abrantes, K., Acuña-Marrero, D., Afonso, A.S., Afonso, P., Anders, D., Araujo, G., Arauz, R., Bach, P., Barnett, A., Bernal, D., Berumen, M.L., Lion, S.B., Bezerra, N.P.A., Blaison, A.V., Block, B.A., Bond, M.E., Bonfil, R., Braun, C.D., Brooks, E.J., Brooks, A., Brown, J., Byrne, M.E., Campana, S.E., Carlisle, A.B., Chapman, D.D., Chapple, T.K., Chisholm, J., Clarke, C.R., Clua, E.G., Cochran, J.E.M., Crochelet, E.C., Dagorn, L., Daly, R., Cortés, D.D., Doyle, T.K., Drew, M., Duffy, C.A.J., Erikson, T., Espinoza, E., Ferreira, L.C., Ferretti, F., Filmalter, J.D., Fischer, G.C., Fitzpatrick, R., Fontes, J., Forget, F., Fowler, M., Francis, M.P., Gallagher, A.J., Gennari, E., Goldsworthy, S.D., Gollock, M.J., Green, J.R., Gustafson, J.A., Guttridge, T.L., Guzman, H.M., Hammerschlag, N., Harman, L., Hazin, F. H.V., Heard, M., Hearn, A.R., Holdsworth, J.C., Holmes, B.J., Howey, L.A., Hoyos, M., Hueter, R.E., Hussey, N.E., Huveneers, C., Irion, D.T., Jacoby, D.M.P., Jewell, O.J.D., Johnson, R., Jordan, L.K.B., Joyce, W., Keating Daly, C.A., Ketchum, J.T., Klimley, A.P., Kock, A.A., Koen, P., Ladino, F., Lana, F.O., Lea, J.S.E., Llewellyn, F., Lyon, W.S., MacDonnell, A., Macena, B.C.L., Marshall, H., McAllister, J.D., Meÿer, M.A., Morris, J.J., Nelson, E.R., Papastamatiou, Y.P., Peñaherrera-Palma, C., Pierce, S.J., Poisson, F., Quintero, L.M., Richardson, A.J., Rogers, P.J., Rohner, C.A., Rowat, D.R.L., Samoilys, M., Semmens, J.M., Sheaves, M., Shillinger, G., Shivji, M., Singh, S., Skomal, G.B., Smale, M.J., Snyders, L.B., Soler, G., Soria, M., Stehfest, K.M., Thorrold, S.R., Tolotti, M.T., Towner, A., Travassos, P., Tyminski, J.P., Vandeperre, F., Vaudo, J.J., Watanabe, Y.Y., Weber, S.B., Wetherbee, B.M., White, T.D., Williams, S., Zárate, P.M., Harcourt, R., Hays, G.C., Meekan, M.G., Thums, M., Irigoien, X., Eguiluz, V.M., Duarte, C.M., Sousa, L.L., Simpson, S.J., Southall, E.J., Sims, D.W., Queiroz, N., Humphries, N.E., Couto, A., Vedor, M., da Costa, I., Sequeira, A.M.M., Mucientes, G., Santos, A.M., Abascal, F.J., Abercrombie, D.L., Abrantes, K., Acuña-Marrero, D., Afonso, A.S., Afonso, P., Anders, D., Araujo, G., Arauz, R., Bach, P., Barnett, A., Bernal, D., Berumen, M.L., Lion, S.B., Bezerra, N.P.A., Blaison, A.V., Block, B.A., Bond, M.E., Bonfil, R., Braun, C.D., Brooks, E.J., Brooks, A., Brown, J., Byrne, M.E., Campana, S.E., Carlisle, A.B., Chapman, D.D., Chapple, T.K., Chisholm, J., Clarke, C.R., Clua, E.G., Cochran, J.E.M., Crochelet, E.C., Dagorn, L., Daly, R., Cortés, D.D., Doyle, T.K., Drew, M., Duffy, C.A.J., Erikson, T., Espinoza, E., Ferreira, L.C., Ferretti, F., Filmalter, J.D., Fischer, G.C., Fitzpatrick, R., Fontes, J., Forget, F., Fowler, M., Francis, M.P., Gallagher, A.J., Gennari, E., Goldsworthy, S.D., Gollock, M.J., Green, J.R., Gustafson, J.A., Guttridge, T.L., Guzman, H.M., Hammerschlag, N., Harman, L., Hazin, F. H.V., Heard, M., Hearn, A.R., Holdsworth, J.C., Holmes, B.J., Howey, L.A., Hoyos, M., Hueter, R.E., Hussey, N.E., Huveneers, C., Irion, D.T., Jacoby, D.M.P., Jewell, O.J.D., Johnson, R., Jordan, L.K.B., Joyce, W., Keating Daly, C.A., Ketchum, J.T., Klimley, A.P., Kock, A.A., Koen, P., Ladino, F., Lana, F.O., Lea, J.S.E., Llewellyn, F., Lyon, W.S., MacDonnell, A., Macena, B.C.L., Marshall, H., McAllister, J.D., Meÿer, M.A., Morris, J.J., Nelson, E.R., Papastamatiou, Y.P., Peñaherrera-Palma, C., Pierce, S.J., Poisson, F., Quintero, L.M., Richardson, A.J., Rogers, P.J., Rohner, C.A., Rowat, D.R.L., Samoilys, M., Semmens, J.M., Sheaves, M., Shillinger, G., Shivji, M., Singh, S., Skomal, G.B., Smale, M.J., Snyders, L.B., Soler, G., Soria, M., Stehfest, K.M., Thorrold, S.R., Tolotti, M.T., Towner, A., Travassos, P., Tyminski, J.P., Vandeperre, F., Vaudo, J.J., Watanabe, Y.Y., Weber, S.B., Wetherbee, B.M., White, T.D., Williams, S., Zárate, P.M., Harcourt, R., Hays, G.C., Meekan, M.G., Thums, M., Irigoien, X., Eguiluz, V.M., Duarte, C.M., Sousa, L.L., Simpson, S.J., Southall, E.J., and Sims, D.W.

Abstract

Our global analysis1 estimated the overlap and fishing exposure risk (FEI) using the space use of satellite-tracked sharks and longline fishing effort monitored by the automatic identification system (AIS)...

Published
2021

14. Recent expansion of marine protected areas matches with home range of grey reef sharks

Author

Bonnin, L, Mouillot, D, Boussarie, G, Robbins, WD, Kiszka, JJ, Dagorn, L, Vigliola, L, Bonnin, L, Mouillot, D, Boussarie, G, Robbins, WD, Kiszka, JJ, Dagorn, L, and Vigliola, L

Abstract

Dramatic declines in reef shark populations have been documented worldwide in response to human activities. Marine Protected Areas (MPAs) offer a useful mechanism to protect these species and their roles in coral reef ecosystems. The effectiveness of MPAs notably relies on compliance together with sufficient size to encompass animal home range. Here, we measured home range of 147 grey reef sharks, Carcharhinus amblyrhynchos, using acoustic telemetry in New Caledonia. The distribution of home range was then compared to local MPA sizes. We report a home range of 12 km2 of reef for the species with strong differences between adult males (21 km2), adult females (4.4 km2) and juveniles (6.2 km2 for males, 2.7 km2 for females). Whereas local historic MPA size seemed adequate to protect reef shark home range in general, these were clearly too small when considering adult males only, which is consistent with the reported failure of MPAs to protect sharks in New Caledonia. Fortunately, the recent implementation of several orders of magnitude larger MPAs in New Caledonia and abroad show that recent Indo-Pacific MPAs are now sufficiently large to protect the home ranges of this species, including males, across its geographical range. However, protection efforts are concentrated in a few regions and cannot provide adequate protection at a global scale.

Published
2021

19. Silky Shark Population Trend In The Indian Ocean Derived From Its Associative Behavior With Floating Objects

Author

Diallo, A, Travassos Tolotti, Mariana, Sabarros, Philippe S.S., Dagorn, L., Deneubourg, J.L., Murua, Hilario, Ruiz, J., Ramos, María LourdesL., Báez, José CarlosC., Abascal, Francisco JavierJ., Pascual-Alayón, Pedro JoséJ., and Capello, M.

Subjects
Centro Oceanográfico de Canarias
Abstract

Silky sharks (Carcharhinus falciformis) figure among the main pelagic shark species caught by the industrial tropical tuna purse-seine fisheries. However, this data was not used so far for estimating their population trends. In this study, using data from the European tropical tuna purse seine fishery, we provide an abundance trend for the silky shark, based on the associative behavior of this species with floating objects (FOBs). Two models were used, describing the dynamics of sharks associated to floating objects (FOBs) in a social and in a non-social case. The parameters estimates of the models were obtained by fitting the distribution of the number of sharks caught per set. The relative abundance indices were derived for the Seychelles area and the Mozambique Channel. For both areas, an upward trend was observed. In the Seychelles area, the abundance index increased by a factor of 3 from 2006 to 2018 and in the Mozambique Channel the increase reached a factor of 15. This modeling approach could be extended to other bycatch species to generate population trends and could be useful for future stock assessment analyses.

Published
2019

20. Preliminary results of BIOFAD project: testing designs and identifying options to mitigate impacts of drifting Fish Aggregating Devices on the ecosystem

Author

Zudaire, I., Tolotti, M., Murua, J., Capello, M., Andrés, M., Cabezas, O., Krug, I., Grande, M., Arregui, I., Uranga, J., Goñi, Nicolás, Ferarios, J.M., Ruiz, J., Baidai, Y., Sabarros, P.S., Ramos, María Lourdes, Báez, José Carlos, Abascal, Francisco Javier, Moreno, Gala, Santiago, J., Dagorn, L., Arrizabalaga, Haritz, and Murua, Hilario

Subjects
purse seiner, FADs, biodegradable materials, Centro Oceanográfico de Canarias, Pesquerías, tropical tuna
Abstract

The EU project BIOFAD was launched in August 2017. This 28-months EU project is coordinated by a Consortium comprising three European research centers: AZTI, IRD (Institut de recherche pour le développement) and IEO (Instituto Español de Oceanografía). The International Seafood Sustainability Foundation (ISSF) is also actively collaborating by providing the biodegradable materials needed to test biodegradable dFADs (drifting FADs). Following IOTC, along with other tuna RFMOs, recommendations and resolutions to promote the use of natural or biodegradable materials for dFADs, this project is seeking to develop and implement the use of dFADs with both characteristics, non-entangling and biodegradable, in the IOTC Convention Area. However, there are no technical guidelines on the type of materials and FAD designs to be used. The main objectives of the project are: (1) to test the use of specific biodegradable materials and designs for the construction of dFADs in real fishing conditions; (2) to identify options to mitigate dFADs impacts on the ecosystem; and (3) to assess the socio-economic viability of the use of biodegradable dFADs in the purse seine tropical tuna fishery. This document shows the preliminary results regarding the effectiveness of around 716 BIOFADs deployed, in terms of tuna aggregation, drift, materials’ durability, etc. in comparison to currently deployed NEFADs (non-entangling dFADs). The project BIOFAD has counted since its inception with the support of the whole EU purse seine tuna fishery and, more recently, with the collaboration of the Korean purse seine fleet.

Published
2019

21. Results of the BIOFAD Project: Testing Designs and Identify Options to Mitigate Impacts of Drifting Fish Aggregating Devices on the Ecosystem

Author

Zudaire, I., Tolotti, M., Murua, J., Capello, M., Andrés, M., Cabezas, O., Krug, I., Grande, M., Arregui, I., Uranga, J., Goñi, Nicolás, Sabarros, P.S., Ferarios, J.M., Ruiz, J., Baidai, Y., Ramos, María Lourdes, Báez, José Carlos, Abascal, Francisco Javier, Moreno, Gala, Santiago, J., Dagorn, L., Arrizabalaga, Haritz, and Murua, Hilario

Subjects
Centro Oceanográfico de Málaga, Pesquerías
Abstract

The EU project BIOFAD was launched in August 2017. This 28-months EU project is coordinated by a Consortium comprising three European research centers: AZTI, IRD (Institut de recherche pour le développement) and IEO (Instituto Español de Oceanografía). The International Seafood Sustainability Foundation (ISSF) is also actively collaborating by providing the biodegradable materials needed to test biodegradable dFADs (drifting FADs). Following IOTC, along with other tuna RFMOs, recommendations and resolutions to promote the use of natural or biodegradable materials for dFADs, this project is seeking to develop and implement the use of dFADs with both characteristics, non-entangling and biodegradable, in the IOTC Convention Area. However, there are no technical guidelines on the type of materials and FAD designs to be used. The main objectives of the project are: (1) to test the use of specific biodegradable materials and designs for the construction of dFADs in real fishing conditions; (2) to identify options to mitigate dFADs impacts on the ecosystem; and (3) to assess the socioeconomic viability of the use of biodegradable dFADs in the purse seine tropical tuna fishery. This document shows the results regarding the effectiveness of 771 BIOFADs deployed within the project, in terms of FAD lifespan, drift, materials’ durability, catch and tuna aggregation in comparison to currently deployed NEFADs (non-entangling dFADs). The project BIOFAD has been supported since its inception by the whole EU purse seine tuna fishery and, more recently, with the collaboration of the Korean purse seine fleet.

Published
2019

22. Global spatial risk assessment of sharks under the footprint of fisheries

Author

Queiroz, N., Humphries, N.E., Couto, A., Vedor, M., da Costa, I., Sequeira, A.M.M., Mucientes, G., Santos, A.M., Abascal, F.J., Abercrombie, D.L., Abrantes, K., Acuña-Marrero, D., Afonso, A.S., Afonso, P., Anders, D., Araujo, G., Arauz, R., Bach, P., Barnett, A., Bernal, D., Berumen, M.L., Bessudo Lion, S., Bezerra, N.P.A., Blaison, A.V., Block, B.A., Bond, M.E., Bonfil, R., Bradford, R.W., Braun, C.D., Brooks, E.J., Brooks, A., Brown, J., Bruce, B.D., Byrne, M.E., Campana, S.E., Carlisle, A.B., Chapman, D.D., Chapple, T.K., Chisholm, J., Clarke, C.R., Clua, E.G., Cochran, J.E.M., Crochelet, E.C., Dagorn, L., Daly, R., Cortés, D.D., Doyle, T.K., Drew, M., Duffy, C.A.J., Erikson, T., Espinoza, E., Ferreira, L.C., Ferretti, F., Filmalter, J.D., Fischer, G.C., Fitzpatrick, R., Fontes, J., Forget, F., Fowler, M., Francis, M.P., Gallagher, A.J., Gennari, E., Goldsworthy, S.D., Gollock, M.J., Green, J.R., Gustafson, J.A., Guttridge, T.L., Guzman, H.M., Hammerschlag, N., Harman, L., Hazin, F.H.V., Heard, M., Hearn, A.R., Holdsworth, J.C., Holmes, B.J., Howey, L.A., Hoyos, M., Hueter, R.E., Hussey, N.E., Huveneers, C., Irion, D.T., Jacoby, D.M.P., Jewell, O.J.D., Johnson, R., Jordan, L.K.B., Jorgensen, S.J., Joyce, W., Keating Daly, C.A., Ketchum, J.T., Klimley, A.P., Kock, A.A., Koen, P., Ladino, F., Lana, F.O., Lea, J.S.E., Llewellyn, F., Lyon, W.S., MacDonnell, A., Macena, B.C.L., Marshall, H., McAllister, J.D., McAuley, R., Meÿer, M.A., Morris, J.J., Nelson, E.R., Papastamatiou, Y.P., Patterson, T.A., Peñaherrera-Palma, C., Pepperell, J.G., Pierce, S.J., Poisson, F., Quintero, L.M., Richardson, A.J., Rogers, P.J., Rohner, C.A., Rowat, D.R.L., Samoilys, M., Semmens, J.M., Sheaves, M., Shillinger, G., Shivji, M., Singh, S., Skomal, G.B., Smale, M.J., Snyders, L.B., Soler, G., Soria, M., Stehfest, K.M., Stevens, J.D., Thorrold, S.R., Tolotti, M.T., Towner, A., Travassos, P., Tyminski, J.P., Vandeperre, F., Vaudo, J.J., Watanabe, Y.Y., Weber, S.B., Wetherbee, B.M., White, T.D., Williams, S., Zárate, P.M., Harcourt, R., Hays, G.C., Meekan, M.G., Thums, M., Irigoien, X., Eguíluz, V.M., Duarte, C.M., Sousa, L.L., Simpson, S.J., Southall, E.J., Sims, D.W., Queiroz, N., Humphries, N.E., Couto, A., Vedor, M., da Costa, I., Sequeira, A.M.M., Mucientes, G., Santos, A.M., Abascal, F.J., Abercrombie, D.L., Abrantes, K., Acuña-Marrero, D., Afonso, A.S., Afonso, P., Anders, D., Araujo, G., Arauz, R., Bach, P., Barnett, A., Bernal, D., Berumen, M.L., Bessudo Lion, S., Bezerra, N.P.A., Blaison, A.V., Block, B.A., Bond, M.E., Bonfil, R., Bradford, R.W., Braun, C.D., Brooks, E.J., Brooks, A., Brown, J., Bruce, B.D., Byrne, M.E., Campana, S.E., Carlisle, A.B., Chapman, D.D., Chapple, T.K., Chisholm, J., Clarke, C.R., Clua, E.G., Cochran, J.E.M., Crochelet, E.C., Dagorn, L., Daly, R., Cortés, D.D., Doyle, T.K., Drew, M., Duffy, C.A.J., Erikson, T., Espinoza, E., Ferreira, L.C., Ferretti, F., Filmalter, J.D., Fischer, G.C., Fitzpatrick, R., Fontes, J., Forget, F., Fowler, M., Francis, M.P., Gallagher, A.J., Gennari, E., Goldsworthy, S.D., Gollock, M.J., Green, J.R., Gustafson, J.A., Guttridge, T.L., Guzman, H.M., Hammerschlag, N., Harman, L., Hazin, F.H.V., Heard, M., Hearn, A.R., Holdsworth, J.C., Holmes, B.J., Howey, L.A., Hoyos, M., Hueter, R.E., Hussey, N.E., Huveneers, C., Irion, D.T., Jacoby, D.M.P., Jewell, O.J.D., Johnson, R., Jordan, L.K.B., Jorgensen, S.J., Joyce, W., Keating Daly, C.A., Ketchum, J.T., Klimley, A.P., Kock, A.A., Koen, P., Ladino, F., Lana, F.O., Lea, J.S.E., Llewellyn, F., Lyon, W.S., MacDonnell, A., Macena, B.C.L., Marshall, H., McAllister, J.D., McAuley, R., Meÿer, M.A., Morris, J.J., Nelson, E.R., Papastamatiou, Y.P., Patterson, T.A., Peñaherrera-Palma, C., Pepperell, J.G., Pierce, S.J., Poisson, F., Quintero, L.M., Richardson, A.J., Rogers, P.J., Rohner, C.A., Rowat, D.R.L., Samoilys, M., Semmens, J.M., Sheaves, M., Shillinger, G., Shivji, M., Singh, S., Skomal, G.B., Smale, M.J., Snyders, L.B., Soler, G., Soria, M., Stehfest, K.M., Stevens, J.D., Thorrold, S.R., Tolotti, M.T., Towner, A., Travassos, P., Tyminski, J.P., Vandeperre, F., Vaudo, J.J., Watanabe, Y.Y., Weber, S.B., Wetherbee, B.M., White, T.D., Williams, S., Zárate, P.M., Harcourt, R., Hays, G.C., Meekan, M.G., Thums, M., Irigoien, X., Eguíluz, V.M., Duarte, C.M., Sousa, L.L., Simpson, S.J., Southall, E.J., and Sims, D.W.

Abstract

Brucellosis is a highly contagious zoonosis affecting humans and a wide range of domesticated and wild animal species. An important element for effective disease containment is to improve knowledge, attitudes and practices (KAP) of afflicted communities. This study aimed to assess the KAP related to brucellosis at the human–animal interface in an endemic area of Egypt and to identify the risk factors for human infection. A matched case–control study was conducted at the central fever hospitals located in six governorates in northern Egypt. Face‐to‐face interviews with cases and controls were conducted using a structured questionnaire. In total, 40.7% of the participants owned farm animals in their households. The overall mean practice score regarding animal husbandry, processing and consumption of milk and dairy products were significantly lower among cases compared with controls (−12.7 ± 18.1 vs. 0.68 ± 14.2, respectively; p < .001). Perceived barriers for notification of animal infection/abortion were predominate among cases and positively correlated with participants’ education. The predictors of having brucellosis infection were consumption of unpasteurized milk or raw dairy products and practicing animal husbandry. Applying protective measures against infection significantly reduced its risk. A model predicting risk factors for brucellosis among those who own animal showed that frequent abortions per animal increased the chance for brucellosis infection among human cases by 50‐fold (95% CI: 8.8–276.9), whereas the use of protective measures in animal care reduced the odds (OR = 0.11 [95% CI: 0.03–0.45]). In conclusion, consumption of unprocessed dairy products was equally important as contact with infected/aborted animals as major risk factors for Brucella spp. infection among humans in Egypt. There is poor knowledge, negative attitudes and risky behaviours among villagers which can perpetuate the risk of brucellosis transmission at the human–animal interface.

Published
2019

23. Repeated long-range migrations of adult males in a common Indo-Pacific reef shark

Author

Bonnin, L, Robbins, WD, Boussarie, G, Kiszka, JJ, Dagorn, L, Mouillot, D, Vigliola, L, Bonnin, L, Robbins, WD, Boussarie, G, Kiszka, JJ, Dagorn, L, Mouillot, D, and Vigliola, L

Abstract

© 2019, Springer-Verlag GmbH Germany, part of Springer Nature. The grey reef shark, Carcharhinus amblyrhynchos, is one of the most abundant coral reef sharks throughout the Indo-Pacific. However, this species has been critically impacted across its range, with well-documented population declines of > 90% attributed to human activities. A key knowledge gap in the successful implementation of grey reef shark conservation plans is the understanding of large-scale movement patterns, along with the associated biological and ecological drivers. To address this shortfall, we acoustically monitored 147 adult and juvenile grey reef sharks of all sexes for more than 2 yr across the New Caledonian archipelago, West Pacific. Here, we document multiple adult males undertaking return journeys of up to nearly 700 km in consecutive years. This constitutes the first evidence of repeated long-range migrations for this species. Although only a limited number of adult males were definitively tracked undertaking migrations, similar timing in changes in the detection patterns of a further 13 animals, mostly adult males, suggests this behavior may be more common than previously thought. The paucity of evidence for juvenile migrations and timing of adult movements suggest that mating is the motivation behind these migrations. Our results have important implications for management, given the potential of mature individuals to recurrently travel outside managed or protected areas. Future management of this species clearly needs to consider the importance of large-scale migratory behaviors when developing management plans.

Published
2019

24. Large-scale movements and site fidelity of two bull sharks Carcharhinus leucas estimated from a double-tagging experiment at Réunion Island (southwest Indian Ocean).

Author

Soria, M, Tremblay, Y, Blaison, A, Forget, F, Crochelet, E, and Dagorn, L

Subjects
SHARKS, BULLS, ISLANDS, OCEAN, TELEMETRY
Abstract

Since 2011, the mean number of bites per year by bull sharks Carcharhinus leucas has increased markedly at Réunion Island. To predict areas and periods of increased risk, we need to better understand the space-use dynamics of individual sharks. In coastal waters off Réunion Island, two bull sharks, one of each sex, were double-tagged and tracked for 174 days (male) and 139 days (female) using pop-up satellite archival tags (PSATs) and acoustic transmitters. Both sharks spent most of their time inshore (58.1% for the male and 89.9% for the female). The female performed short excursions but typically remained inshore. The male alternated between spending residence time along the coast and undertaking wide-ranging movements, including one extensive open-ocean excursion to the vicinity of a seamount situated about 210 km from the island. Differences in the residency and home range between the two sharks probably reflect different patterns of foraging and mating behaviours. Our results highlight the advantages of double-tagging in telemetry studies that attempt to estimate the degree of habitat fidelity of a species and illustrate the need to consider the movement patterns of sharks at different scales when developing efficient risk-mitigation management. [ABSTRACT FROM AUTHOR]

Published
2021
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28. Balanced Harvest in the Real World. Scientific, Policy and Operational Issues in an Ecosystem Approach to Fisheries

Author

Garcia, S.M., Bianchi, G., Charles, A., Kolding, J., Rice, J., Rochet, M.J., Zhou, S., Delius, G., Reid, D., van Zwieten, P.A.M., Atcheson, M., Bartley, D., Borges, L., Bundy, A., Dagorn, L., Dunn, D., Hall, M., Heino, M., Jacobsen, B., Jacobsen, N.S., Law, R., Makino, M., Martin, F., Skern-Mauritzen, M., Suuronen, P., and Symons, D.

Subjects
Aquaculture and Fisheries, Aquacultuur en Visserij, WIAS, Life Science, Wageningen Marine Research
Abstract

The concept of the Ecosystem Approach has entered the fishery harvesting discussions both from fishery perspectives (Reykjavik Declaration; FAO 2003 Annex to the Code of Conduct and from the principles of the Ecosystem Approach adopted by the CBD in 1995. Both perspectives establish the need to maintain ecosystem structure and functioning, whether for sustainable use of biodiversity (CBD) or simply to keep exploited ecosystems healthy and productive (fisheries). In response, the “Balanced Harvest” (BH) concept was suggested by a group of scientists brought together by the IUCN Fisheries Experts Group during the CBD CoP 10 in 2010. The meeting and the BH concept as consolidated there highlighted some of the collateral ecological effects of current fishing patterns and unbalanced removals of particular components of the food web, stimulating a critical rethinking of current approaches to fisheries management. The meeting on “Balanced Harvest in the real world - Scientific, policy and operational issues in an ecosystem approach to fisheries” (Rome, September 29-October 2, 2014) examined the progress made since 2010 on a number of fronts. It considered questions related to the scientific underpinning of the BH concept, including theory, modelling, and empirical observations. It began to explore the economic, policy and management implications of harvesting in a more balanced way.

Published
2015

29. Population assessment of tropical tuna based on their associative behavior around floating objects

Author

Capello, M., Deneubourg, J. L., Robert, Marianne, Holland, K. N., Schaefer, K. M., Dagorn, L., Capello, M., Deneubourg, J. L., Robert, Marianne, Holland, K. N., Schaefer, K. M., and Dagorn, L.

Abstract

Estimating the abundance of pelagic fish species is a challenging task, due to their vast and remote habitat. Despite the development of satellite, archival and acoustic tagging techniques that allow the tracking of marine animals in their natural environments, these technologies have so far been underutilized in developing abundance estimations. We developed a new method for estimating the abundance of tropical tuna that employs these technologies and exploits the aggregative behavior of tuna around floating objects (FADs). We provided estimates of abundance indices based on a simulated set of tagged fish and studied the sensitivity of our method to different association dynamics, FAD numbers, population sizes and heterogeneities of the FAD-array. Taking the case study of yellowfin tuna (Thunnus albacares) acoustically-tagged in Hawaii, we implemented our approach on field data and derived for the first time the ratio between the associated and the total population. With more extensive and long-term monitoring of FAD-associated tunas and good estimates of the numbers of fish at FADs, our method could provide fisheries-independent estimates of populations of tropical tuna. The same approach can be applied to obtain population assessments for any marine and terrestrial species that display associative behavior and from which behavioral data have been acquired using acoustic, archival or satellite tags.

Published
2016
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32. Targeting bigger schools can reduce ecosystem impacts of fisheries

Author

Dagorn, L., Filmalter, J.D., Forget, F., Amandè, M.J. (Monin J.), Hall, M., Williams, P., Murua, H. (Hilario), Ariz-Tellería, F.J. (Francisco Javier), Chavance, P., and Bez, N.

Subjects
RENDEMENT, IMPACT DE LA PECHE, APPROCHE ECOSYSTEMIQUE, DISPOSITIF DE CONCENTRATION DES POISSONS, GESTION DES PECHES, PRISE ACCESSOIRE, Centro Oceanográfico de Canarias, ANALYSE QUANTITATIVE, Pesquerías, PECHE THONIERE, MARQUAGE
Abstract

Sí

Published
2012

33. Feeding ecology of silky sharks Carcharhinus falciformis associated with floating objects in the western Indian Ocean.

Author

Filmalter, J. D., Cowley, P. D., Potier, M., Ménard, F., Smale, M. J., Cherel, Y., and Dagorn, L.

Subjects
ANIMAL feeding behavior, SILKY shark, FISH ecology, FISH feeds, FISH aggregation devices, ANIMAL behavior
Abstract

The silky shark Carcharhinus falciformis is commonly associated with floating objects, including fish aggregating devices ( FADs), in the Indian Ocean. While the motives for this associative behaviour are unclear, it does make them vulnerable to capture in the tuna purse seine fishery that makes extensive use of FADs. Here, the diet of 323 C. falciformis, caught at FADs in the Indian Ocean, was investigated to test the hypothesis that trophic benefits explain the associative behaviour. A high proportion of stomachs with fresh contents (57%) suggested that extensive feeding activity occurred while associated with FADs. Multiple dietary indices showed that typical non-associative prey types dominated, but were supplemented with fishes typically found at FADs. While the trophic benefits of FAD association may be substantial, our results suggest that associative behaviour is not driven solely by feeding. [ABSTRACT FROM AUTHOR]

Published
2017
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36. Modeling tuna behaviour near floating objects : from individuals to aggregations

Author

Dagorn, L., Josse, E., Bach, P., and Arnaud Bertrand

Subjects
FLOTTEUR, REPARTITION VERTICALE, BANC DE POISSONS, DISPOSITIF DE CONCENTRATION DES POISSONS, THON, REPARTITION HORIZONTALE, COMPORTEMENT ALIMENTAIRE, DYNAMIQUE DE POPULATION, CAPTEUR, TELEMETRIE ULTRASONIQUE, LOGIQUE FLOUE, DISTRIBUTION SPATIALE, MODELISATION
Abstract

Un modèle de logique floue du comportement des thons autour de dispositifs de concentration de poissons (DCP) est développé pour reproduire les différences individuelles observées dans les mouvements horizontaux à partir d'expériences de télémétrie ultrasonique. Dans ce modèle, le comportement d'un individu est basé sur son environnement local (DCP et proies) et sur son état interne (taux de remplissage de l'estomac), qui dépend de ses actions passées. Des capteurs internes déterminent la motivation du poisson, qui, combinée avec des capteurs externes, détermine ses mouvements. Les informations sensorielles et la motivation sont modélisées avec des ensembles flous. Un individu est toujours attiré par un DCP s'il se trouve dans un certain rayon autour de celui-ci. Le temps passé autour d'un DCP dépend de la motivation alimentaire du poisson et de son environnement local. Si le poisson n'a pas faim, il reste autour du DCP. Sinon, le poisson doit rechercher de la nourriture, et peut ainsi quitter le DCP s'il ne trouve pas de proies aux alentours. En variant les conditions environnementales autour du DCP, ce modèle reproduit les différents mouvements horizontaux observés chez les thons. Le modèle est ensuite étendu pour permettre la coexistence de plusieurs individus, sans aucune interaction directe ou indirecte entre ceux-ci. Ceci permet d'étudier les effets des comportements individuels sur les agrégations de thons autour de DCP. Le modèle prédit avec précision les dynamiques temporelles des agrégations de thons autour de DCP. En simulant différents réseaux de DCP, le modèle permet d'estimer la meilleure organisation spatiale des DCP. (Résumé d'auteur)

Published
2000

38. Quantifying the interplay between environmental and social effects on aggregated-fish dynamics

Author

Capello, Manuela, Soria, M, Cotel, Pascal, Deneubourg, Jean-Louis, Dagorn, L., Capello, Manuela, Soria, M, Cotel, Pascal, Deneubourg, Jean-Louis, and Dagorn, L.

Abstract

Demonstrating and quantifying the respective roles of social interactions and external stimuli governing fish dynamics is key to understanding fish spatial distribution. If seminal studies have contributed to our understanding of fish spatial organization in schools, little experimental information is available on fish in their natural environment, where aggregations often occur in the presence of spatial heterogeneities. Here, we applied novel modeling approaches coupled to accurate acoustic tracking for studying the dynamics of a group of gregarious fish in a heterogeneous environment. To this purpose, we acoustically tracked with submeter resolution the positions of twelve small pelagic fish (Selar crumenophthalmus) in the presence of an anchored floating object, constituting a point of attraction for several fish species. We constructed a field-based model for aggregated-fish dynamics, deriving effective interactions for both social and external stimuli from experiments. We tuned the model parameters that best fit the experimental data and quantified the importance of social interactions in the aggregation, providing an explanation for the spatial structure of fish aggregations found around floating objects. Our results can be generalized to other gregarious species and contexts as long as it is possible to observe the fine-scale movements of a subset of individuals. © 2011 Capello et al., SCOPUS: ar.j, info:eu-repo/semantics/published

Published
2011

39. Visual censuses around drifting fish aggregating devices (FADs): a new approach for assessing the diversity of fish in open-ocean waters

Author

Gaertner, J, Taquet, Marc, Dagorn, L, Merigot, B, Aumeeruddy, R, Sancho, G, Itano, D, Gaertner, J, Taquet, Marc, Dagorn, L, Merigot, B, Aumeeruddy, R, Sancho, G, and Itano, D

Abstract

This study provides a baseline measure of pelagic fish species diversity around fish aggregating devices (FADs) in the Western Indian Ocean. Using data from visual censuses made by SCUBA divers around drifting FADs we (1) analysed 11 diversity indices describing 4 main components of pelagic diversity: number of species, evenness, taxonomic diversity and rarity and (2) discussed the viability of using visual censuses around FADs to monitor temporal and spatial changes in diversity patterns of pelagic fishes in the future. Our results not only show that a single index, such as species richness or the Shannon-Wiener index, cannot provide a complete description of pelagic fish diversity around FADs, but also that some components of diversity appear to be multifaceted themselves and require the simultaneous use of several complementary indices in order to be accurately described and monitored. Despite a limited sampling effort, our results suggest that using visual censuses around FADs could provide reproducible 'relative' indices of diversity for a well-delimited assemblage of species (intra- and extranatant species in the epipelagic domain). In this context, we propose a preliminary 'short list' of diversity indices based firstly on their complementarity and secondly on their simplicity. While visual censuses of pelagic fishes at FADs (like any other sampling method) cannot give an exhaustive picture of diversity, they are a fishery-independent survey method that can complement other sampling techniques and provide reproducible information to monitor the diversity of these very difficult-to-access pelagic fish communities.

Published
2008
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42. Characterizing fish communities associated with drifting fish aggregating devices (FADs) in the Western Indian Ocean using underwater visual surveys

Author

Taquet, Marc, Sancho, G, Dagorn, L, Gaertner, J, Itano, D, Aumeeruddy, R, Wendling, B, Peignon, C, Taquet, Marc, Sancho, G, Dagorn, L, Gaertner, J, Itano, D, Aumeeruddy, R, Wendling, B, and Peignon, C

Abstract

We adapted a visual census method, mainly used in demersal and reef fish studies, to characterize fish communities associated to drifting fish aggregating devices (FADs) in the Western Indian Ocean. Drifting FAD associated fishes from both equatorial (Seychelles) and tropical waters (Reunion Island) were examined by divers. A total of 32 species (belonging to 16 families) were observed associated with drifting FADs in equatorial waters, and 24 species (14 families) were found around FADs in tropical waters. Twenty species were found in both regions. The highest number of species observed at a single FAD was 18 (12 +/- 2, mean +/- SD) in equatorial and 13 (10 +/- 3) in tropical waters, not counting circumnatant species loosely associated with the FAD. Some species like Kyphosus vaigiensis, Canthidermis maculata, Elagatis bipinnulata, Acanthocybium solandri and Coryphaena hippurus were observed on all or most of the surveys. In this study, the contribution in biomass of the 18 common species associated with drifting FADs (but excluding circumnatant species), represents more than 98% of the biomass. The overall biomass values of closely associated species remains well below tuna biomass estimates for circumnatant tuna schools at FADs, estimated as high as 200 tons. The species that most significantly contribute to the by-catch in tuna purse-seines logically match those that showing the highest biomass values in our surveys (Carcharhinus spp., Elagatis bipinnulata, Coryphaena hippurus, Canthidermis maculata, and Acanthocybium solandri). One of the most abundant and ubiquitous species in our study was the spotted oceanic triggerfish Canthidermis maculata that sometimes formed massive schools of many thousands individuals around the drifting FADs. Future research is needed to explore the role of such non tuna species in the attraction and aggregation processes of tuna around drifting FADs.

Published
2007

43. Satellite-linked acoustic receivers to observe behavior of fish in remote areas

Author

Dagorn, L, Pincock, D, Girard, C, Holland, K, Taquet, Marc, Sancho, G, Itano, D, Aumeeruddy, R, Dagorn, L, Pincock, D, Girard, C, Holland, K, Taquet, Marc, Sancho, G, Itano, D, and Aumeeruddy, R

Abstract

Automated acoustic receivers are now widely used by biologists to study the behavior of fish. However, currently available acoustic receivers require physical recovery of the units to download stored data. Such operation is often difficult in remote study areas like in the open ocean. We present a new satellite-linked acoustic receiver (Vemco VR3-Argos) that allows downloading data through a satellite uplink (Argos). The VR3-Argos can last up to one year, sending GPS positions and tag data at regular time intervals. We illustrate the advantages of this new technology with tagging data from 121 fish of seven species (yellowfin tuna, bigeye tuna, skipjack tuna, wahoo, dolphinfish, silky shark and oceanic triggerfish) caught and released around drifting fish aggregating devices (FADs) in the Western Indian Ocean, far from any land. In opposition with the classic acoustic receivers (Vemco VR2), the use of VR3-Argos allowed to collect data for several weeks after leaving the drifting FADs. Maximum residence times of 3 days for bigeye tuna, 7 days for skipjack, 8 days for wahoo, 10 days for silky shark and 15 days for yellowfin tuna, dolphinfish and oceanic triggerfish could be recorded. VR2 and VR3-Argos are equivalent in terms of quality of residence times data, however depth data obtained through satellites are aggregated in 8 classes for compression purposes, which leads to a loss of precision available with raw data. Future directions of this technology are discussed.

Published
2007
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44. Behavior of dolphinfish (Coryphaena hippurus) around drifting FADs as observed from automated acoustic receivers

Author

Taquet, Marc, Dagorn, L, Gaertner, J, Girard, C, Aumerruddy, R, Sancho, G, Itano, D, Taquet, Marc, Dagorn, L, Gaertner, J, Girard, C, Aumerruddy, R, Sancho, G, and Itano, D

Abstract

To study the behavior of dolphinfish (Coryphaena hippurus) around drifting Fish Aggregating Devices (FADs), we tagged individuals with long-lived, coded sonic transmitters and attached automated sonic receivers to drifting FADs in two regions of the Western Indian Ocean. Among the three tagging methods used in this study (surgery, external hooks, underwater bait without capture), the latest resulted in residence times significantly shorter than the other ones, likely due to regurgitation. Dolphinfish tagged with the two other methods usually stayed several days associated to FADs (Kaplan-Meier survival analysis 5.09 days, mean 6.25 days, SD 4.39 days, maximum 15.26 days), drifting with them. There was no significant difference in the residence times of dolphinfish in equatorial and tropical areas. While associated to FADs, dolphinfish spent most of their time close to floating object (< 365 m). The total time spent away from FADs was low (median 8%), and likely corresponded to making feeding excursions. Dolphinfish did not form a single school while associated to a given FADs, but formed multiple small schools. FADs are likely to be sites with exchanges of individuals between schools. These results are discussed in regards to the possibility of FADs acting as ecological traps and the validity of meeting-point hypotheses as an explanation for fish aggregations under floating objects.

Published
2007
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45. Homing abilities of dolphinfish (Coryphaena hippurus) displaced from fish aggregating devices (FADs) determined using ultrasonic telemetry

Author

Girard, C, Dagorn, L, Taquet, Marc, Aumeeruddy, R, Peignon, C, Benhamou, S, Girard, C, Dagorn, L, Taquet, Marc, Aumeeruddy, R, Peignon, C, and Benhamou, S

Abstract

We conducted displacement experiments using acoustic tags to study the orientation abilities of dolphinfish (Coryphaena hippurus) around FADs. Eleven fish were passively monitored using coded transmitters and acoustic receivers attached to FADs, while seven others were actively tracked with a vessel using continuous acoustic tags equipped with pressure sensors. All these 18 dolphinfish were captured close to a FAD and released between 70 and 1720 m from it. Five fish out of the 14 that were displaced at more than 360 m from a FAD ( estimated detection range of our acoustic receivers, defining the target area during our experiment) returned to the target area. With one individual successfully returning to the target area after having been released at 1600 m from the FAD, the rate of return of fish released up to this distance was significantly higher than expected if they were moving at random, but many fish released at intermediate distances moved in other directions. Based on detailed statistical analysis of the return score, we estimated that dolphinfish are able to orientate towards a FAD area from at least 820 m. The connection between our definition of the target area and the association area of dolphinfish around a FAD is discussed, as well as the impact of stress and motivation in the rates of return observed. More experiments should be conducted to improve this first estimate. Specific experiments should also be designed to more accurately determine the association range of fish around FADs and their motivation to orientate towards FADs.

Published
2007
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47. Foraging of the green sea turtle Chelonia mydas on seagrass beds at Mayotte Island (Indian Ocean), determined by acoustic transmitters

Author

Taquet, Coralie, Taquet, Marc, Dempster, T, Soria, M, Ciccione, S, Roos, David, Dagorn, L, Taquet, Coralie, Taquet, Marc, Dempster, T, Soria, M, Ciccione, S, Roos, David, and Dagorn, L

Abstract

We studied the foraging rhythms of green sea turtles Chelonia mydas on the seagrass beds of N'Gouja Bay, Mayotte Island (Comoros Archipelago) with acoustic transmitters and moored listening stations. We monitored 8 tagged turtles (4 probable males, 3 probable females and 1 immature), from 70 to 109 cm curved carapace length (CCL), for durations ranging from 5 to 92 d. The turtles exhibited a regular diel pattern: they foraged mainly during the day (on average 87% of seagrass detections were between 06:00 and 18:00 h) and rested on the inner reef slope during the night. Night time feeding activities were observed on the seagrass bed when the night light was high. The presence of turtles on the seagrass bed at night was significantly correlated with a night light index (r = 0.54, p = 0.002), which included both moon light and cloudiness indices. Behaviour of the only immature individual observed was similar to adult turtles, although it rested more frequently around noon. All turtles displayed a high fidelity to 1 foraging site within the seagrass bed. Acoustic transmitters and permanent listening stations are an appropriate technique for long-term behavioural studies of turtles, with no human interaction with turtles during tracking, and represent a suitable technique to assess the possible effects of environmental changes or human activities upon green turtle behaviour.

Published
2006
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