Oceanic islands are productive ecosystems, and so have higher densities of many marine predators. We investigated the dynamics of elasmobranch and teleost predators in coastal waters off Réunion Island, Indian Ocean, using fisheries-independent data from a preventative shark fishing program from January 2014 to December 2019. We developed a moonlight index that calculates exact moonlight through incorporating lunar azimuth, elevation angle and island topography. We quantified spatial–temporal and environmental drivers of occurrence using zero-inflated mixed models and assessed species-specific catchability in the program. A consistent segregated pattern was observed with higher occurrence of all species at dusk and after-dusk associated with lower luminosity. Scalloped hammerhead sharks (Sphyrna lewini) and giant trevally (Caranx ignobilis) were found to patrol coastal waters earlier in the day than the other species. Tiger (Galeocerdo cuvier) and bull (Carcharhinus leucas) sharks showed high spatial segregation, potentially reducing competition. Teleost predators were found more frequently inside the coral reef environment of the Marine Protected Area but there was no clear pattern for sharks. Seasonality was observed for giant trevally, stingrays, bull sharks, and giant guitarfish (Rhynchobatus australiae), with higher presence during early winter periods related to turbidity, photosynthetically available radiation, and temperature. Inter-annual variation in catch rates suggested that juvenile tiger sharks might be replacing bull sharks in nearshore habitats, and the consequences for mitigation of shark bite hazard are discussed. Operational alternatives are proposed to enhance reducing the impacts of preventative shark fishing upon critically endangered species, improve their conservation and ensure local ecosystem balance.
This is a preview of subscription content, access via your institution.
Buy single article
Instant access to the full article PDF.
Tax calculation will be finalised during checkout.
Subscribe to journal
Immediate online access to all issues from 2019. Subscription will auto renew annually.
Tax calculation will be finalised during checkout.
The data used in the present research was collected by the Shark Security Centre (collected from the field from 2018 to 2019, and from the Fisheries Committee for the data previously collected). Datasets used in the publication are available on the SIMM website (link to be provided).
Afonso AS, Andrade HA, Hazin FHV (2014) Structure and dynamics of the shark assemblage off Recife. Northeastern Brazil PLoS One 9:e102369
Afonso AS, Garla R, Hazin FHV (2017a) Tiger sharks can connect equatorial habitats and fisheries across the Atlantic Ocean basin. PLoS ONE 12:1–15
Afonso AS, Hazin FHV, Carvalho F, Pacheco JC, Hazin H, Kerstetter DW, Murie D, Burgess GH (2011) Fishing gear modifications to reduce elasmobranch mortality in pelagic and bottom longline fisheries off Northeast Brazil. Fish Res 108:336–343
Afonso AS, Niella YV, Hazin FHV (2017b) Inferring trends and linkages between shark abundance and shark bites on humans for shark-hazard mitigation. Mar Freshw Res 68:1354–1365
Austin RH, Phillips BF, Webb DJ (1976) A method for calculating moonlight illuminance at the earth’s surface. J Appl Ecol 13:741
Ballas R, Saetta G, Peuchot C, Elkienbaum P, Poinsot E (2017) Clinical features of 27 shark attack cases on La Réunion Island. J Trauma Acute Care Surg 82:952–955
Behrenfeld MJ, Westberry TK, Boss ES, O’Malley RT, Siegel DA, Wiggert JD, Franz BA, McClain CR, Feldman GC, Doney SC, Moore JK, Dall’Olmo G, Milligan AJ, Lima I, Mahowald N (2009) Satellite-detected fluorescence reveals global physiology of ocean phytoplankton. Biogeosciences 6:779–794
Benoit-Bird KJ, Au WWL (2006) Extreme diel horizontal migrations by a tropical nearshore resident micronekton community. Mar Ecol Prog Ser 319:1–14
Benoit-Bird KJ, Au WWL, Wisdom DW (2009) Nocturnal light and lunar cycle effects on diel migration of micronekton. Limnol Oceanogr 54:1789–1800
Blaison A, Jaquemet S, Guyomard D, Vangrevelynghe G, Gazzo T, Cliff G, Cotel P, Soria M (2015) Seasonal variability of bull and tiger shark presence on the west coast of Reunion Island, western Indian Ocean. African J Mar Sci 37:199–208
Block BA, Jonsen ID, Jorgensen SJ, Winship AJ, Shaffer SA, Bograd SJ, Hazen EL, Foley DG, Breed GA, Harrison AL, Ganong JE, Swithenbank A, Castleton M, Dewar H, Mate BR, Shillinger GL, Schaefer KM, Benson SR, Weise MJ, Henry RW, Costa DP (2011) Tracking apex marine predator movements in a dynamic ocean. Nature 475:86–90
Broadhurst MK, Butcher PA, Millar RB, Marshall JE, Peddemors VM (2014) Temporal hooking variability among sharks on south-eastern Australian demersal longlines and implications for their management. Glob Ecol Conserv 2:181–189
Brooks ME, Kristensen K, van Benthem KJ, Magnusson A, Berg CW, Nielsen A, Skaug HJ, Maechler M, Bolker BM (2017) glmmTMB balances speed and flexibility among packages for zero-inflated generalized linear mixed modeling. R J 9:378–400
Carlson JK, Ribera MM, Conrath CL, Heupel MR, Burgess GH (2010) Habitat use and movement patterns of bull sharks Carcharhinus leucas determined using pop-up satellite archival tags. J Fish Biol 77:661–675
Cliff G, Dudley SF (1991) Sharks caught in the protective gill nets off Natal, South Africa. 4. the bull shark Carcharhinus leucas valenciennes. South African J Mar Sci 10:253–270
Conand F, Marsac F, Tessier E, Conand C (2007) A ten-year period of daily sea surface temperature at a coastal station in Reunion Island, Indian Ocean (July 1993–April 2004): patterns of variability and biological responses. West Indian Ocean J Mar Sci 6:1–16
De Bruyn P, Dudley SFJ, Cliff G, Smale MJ (2005) Sharks caught in the protective gill nets off KwaZulu-Natal, South Africa. 11. The scalloped hammerhead shark Sphyrna lewini (Griffith and Smith). African J Mar Sci 27:517–528
Dicken ML, Cliff G, Winker H (2016) Sharks caught in the KwaZulu-Natal bather protection programme, South Africa. 13. The tiger shark Galeocerdo cuvier. African J Mar Sci 38:285–301
Doty MS, Oguri M (1956) The island mass effect. ICES J Mar Sci 22:33–37
Driggers WB III, Campbell MD, Hoffmayer ER, Ingram GW (2012) Feeding chronology of six species of carcharhinid sharks in the western North Atlantic Ocean as inferred from longline capture data. Mar Ecol Prog Ser 465:185–192
Dudley SFJ (1995) Shark nets in KwaZulu-Natal: an evaluation of catches and alternatives. University of Cape Town
Dudley SFJ (1997) A comparison of the shark control programs of New South Wales and Queensland (Australia) and KwaZulu-Natal (South Africa). Ocean Coast Manag 34:1–27
Dudley SFJ, Simpfendorfer CA (2006) Population status of 14 shark species caught in the protective gillnets off KwaZulu-Natal beaches, South Africa, 1978–2003. Mar Freshw Res 57:225–240
Duncan KM, Holland KN (2006) Habitat use, growth rates and dispersal patterns of juvenile scalloped hammerhead sharks Sphyrna lewini in a nursery habitat. Mar Ecol Prog Ser 312:211–221
Estes JA, Heithaus M, McCauley DJ, Rasher DB, Worm B (2016) Megafaunal impacts on structure and function of ocean ecosystems. Annu Rev Environ Resour 41:83–116
Feng J, Durant JM, Stige LC, Hessen DO, Hjermann DØ, Zhu L, Llope M, Stenseth NC (2015) Contrasting correlation patterns between environmental factors and chlorophyll levels in the global ocean. Global Biogeochem Cycles 29:2095–2107
Ferreira LC, Thums M, Meeuwig JJ, Vianna GMS, Stevens J, McAuley R, Meekan MG (2015) Crossing latitudes-long-distance tracking of an apex predator. PLoS ONE 10:1–17
Ferretti F, Jorgensen S, Chapple TK, De Leo G, Micheli F (2015) Reconciling predator conservation with public safety. Front Ecol Environ 13:412–417
Frank B (2016) Human-wildlife conflicts and the need to include tolerance and coexistence: an introductory comment. Soc Nat Resour 29:738–743
Friedlander AM, DeMartini EE (2002) Contrasts in density, size, and biomass of reef fishes between the northwestern and the main Hawaiian islands: the effects of fishing down apex predators. Mar Ecol Prog Ser 230:253–264
Gallagher AJ, Orbesen ES, Hammerschlag N, Serafy JE (2014) Vulnerability of oceanic sharks as pelagic longline bycatch. Glob Ecol Conserv 1:50–59
Game ET, Meijaard E, Sheil D, Mcdonald-Madden E (2014) Conservation in a wicked complex world; challenges and solutions. Conserv Lett 7:271–277
Gibbs L, Warren A (2014) Killing Sharks: cultures and politics of encounter and the sea. Aust Geogr 45:101–107
Guyomard D, Perry C, Tournoux PU, Cliff G, Peddemors V, Jaquemet S (2019) An innovative fishing gear to enhance the release of non-target species in coastal shark-control programs: the SMART (shark management alert in real-time) drumline. Fish Res 216:6–17
Souri AH, Azizi A (2013) Removing bowtie phenomenon by correction of panoramic effect in MODIS imagery. Int J Comput Appl 68:12–16
Halpern BS, Frazier M, Afflerbach J, Lowndes JS, Micheli F, O’Hara C, Scarborough C, Selkoe KA (2019) Recent pace of change in human impact on the world’s ocean. Sci Rep 9:1–8
Hammerschlag N, Martin RA, Fallows C (2006) Effects of environmental conditions on predator-prey interactions between white sharks (Carcharodon carcharias) and Cape fur seals (Arctocephalus pusillus pusillus) at Seal Island, South Africa. Environ Biol Fishes 76:341–350
Hammerschlag N, Skubel RA, Calich H, Nelson ER, Shiffman DS, Wester J, Macdonald CC, Cain S, Jennings L, Enchelmaier A, Gallagher AJ (2017) Nocturnal and crepuscular behavior in elasmobranchs: a review of movement, habitat use, foraging, and reproduction in the dark. Bull Mar Sci 93:355–374
Hardiman N, Burgin S, Shao J (2019) News media portrayal of attributed stakeholder attitudes to shark management in Australia. Hum Dimens Wildl 24:548–563
Hazen EL, Jorgensen S, Rykaczewski RR, Bograd SJ, Foley DG, Jonsen ID, Shaffer SA, Dunne JP, Costa DP, Crowder LB, Block BA (2013) Predicted habitat shifts of Pacific top predators in a changing climate. Nat Clim Chang 3:234–238
Heithaus MR, Frid A, Wirsing AJ, Worm B (2008) Predicting ecological consequences of marine top predator declines. Trends Ecol Evol 23:202–210
Heywood KJ, Barton ED, Simpson JH (2008) The effects of flow disturbance by an oceanic Island. J Mar Res 48:55–73
Holmes BJ, Sumpton WD, Mayer DG, Tibbetts IR, Neil DT, Bennett MB (2012) Declining trends in annual catch rates of the tiger shark (Galeocerdo cuvier) in Queensland, Australia. Fish Res 129–130:38–45
Hueter RE, Mann DA, Maruska KP, Sisneros JA, Demski LS (2004) Sensory biology of elasmobranchs. In: Carrier JC, Musick JA, Heithaus MR (eds) Biology of sharks and their relatives. CRC Press, Boca Raton, pp 325–368
Kyne PM, Jabado RW, Rigby CL, Gore MA, Caroline M, Herman KB, Cheok J, Ebert DA, Simpfendorfer CA, Nicholas K (2020) The thin edge of the wedge: extremely high extinction risk in wedgefishes and giant guitarfishes. Aquat Conserv Mar Freshw Ecosyst 1–45
Lagabrielle E, Allibert A, Kiszka JJ, Loiseau N, Kilfoil JP, Lemahieu A (2018) Environmental and anthropogenic factors affecting the increasing occurrence of shark-human interactions around a fast-developing Indian Ocean island. Sci Rep 8:3676
Le Croizier G, Lorrain A, Sonke JE, Jaquemet S, Schaal G, Renedo M, Besnard L, Cherel Y, Point D (2020) Mercury isotopes as tracers of ecology and metabolism in two sympatric shark species. Environ Pollut 265:114931
Lee KA, Roughan M, Harcourt RG, Peddemors VM (2018) Environmental correlates of relative abundance of potentially dangerous sharks in nearshore areas, southeastern Australia. Mar Ecol Prog Ser 599:157–179
Lee ZP, Darecki M, Carder KL, Davis CO, Stramski D, Rhea WJ (2005) Diffuse attenuation coefficient of downwelling irradiance: an evaluation of remote sensing methods. J Geophys Res C Ocean 110:1–9
Lowry M, Williams D, Metti Y (2007) Lunar landings-relationship between lunar phase and catch rates for an Australian gamefish-tournament fishery. Fish Res 88:15–23
Lutjeharms JRE, Cooper J, Roberts M (2000) Upwelling at the inshore edge of the Agulhas Current. Cont Shelf Res 20:737–761
McCauley DJ, Gellner G, Martinez ND, Williams RJ, Sandin SA, Micheli F, Mumby PJ, McCann KS (2018) On the prevalence and dynamics of inverted trophic pyramids and otherwise top-heavy communities. Ecol Lett 21:439–454
Meyer CG, Anderson JM, Coffey DM, Hutchinson MR, Royer MA, Holland KN (2018) Habitat geography around Hawaii’s oceanic islands influences tiger shark (Galeocerdo cuvier) spatial behaviour and shark bite risk at ocean recreation sites. Sci Rep 8:1–18
Myers N, Mittermeier RA, Mittermeier CG, Fonseca GAB, Kent J (2000) Biodiversity hotspots for conservation priorities. Nature 403:853–858
Niella YV (2020) Moonlight-index R code. https://github.com/YuriNiella/Moonlight-index.
Niella YV, Smoothey AF, Peddemors V, Harcourt R (2020) Predicting changes in distribution of a large coastal shark in the face of the strengthening East Australian Current. Mar Ecol Prog Ser 642:163–177
Niella YV, Afonso AS, Hazin FHV (2017a) Bioecology and movements of bull sharks, carcharhinus leucas, caught in a long-term longline survey off northeastern Brazil. Neotrop Ichthyol 15:1–9
Niella YV, Hazin FHV, Afonso AS (2017b) Detecting multispecific patterns in the catch composition of a fisheries-independent longline survey. Mar Coast Fish 9:388–395
Ortega LA, Heupel MR, Van BP, Motta PJ (2009) Movement patterns and water quality preferences of juvenile bull sharks (Carcharhinus leucas) in a Florida estuary. Environ Biol Fishes 84:361–373
Pirog A, Jaquemet S, Ravigné V, Cliff G, Clua E, Holmes BJ, Hussey NE, Nevill JEG, Temple AJ, Berggren P, Vigliola L, Magalon H (2019a) Genetic population structure and demography of an apex predator, the tiger shark Galeocerdo cuvier. Ecol Evol 9:5551–5571
Pirog A, Magalon H, Poirout T, Jaquemet S (2019b) Reproductive biology, multiple paternity and polyandry of the bull shark Carcharhinus leucas. J Fish Biol 1:1–12
Pirog A, Magalon H, Poirout T, Jaquemet S (2020) New insights into the reproductive biology of the tiger shark Galeocerdo cuvier and no detection of polyandry in Reunion Island, western Indian Ocean. Mar Freshw Res 71:1301–1312
Pirog A, Ravigné V, Fontaine MC, Rieux A, Gilabert A, Cliff G, Clua E, Daly R, Heithaus MR, Kiszka JJ, Matich P, Nevill JEG, Smoothey AF, Temple AJ, Berggren P, Jaquemet S, Magalon H (2019c) Population structure, connectivity, and demographic history of an apex marine predator, the bull shark Carcharhinus leucas. Ecol Evol 9:12980–13000
Poisson F, Gaertner JC, Taquet M, Durbec JP, Bigelow K (2010) Effects of lunar cycle and fishing operations on longline-caught pelagic fish: fishing performance, capture time, and survival of fish. Fish Bull 108:268–281
Powell M (2017) A world of fins and fences: Australian and South African shark management in the transoceanic south. Int Rev Environ Hist 3:5–30
Reid DD, Robbins WD, Peddemors VM (2011) Decadal trends in shark catches and effort from the New South Wales, Australia, shark meshing program 1950–2010. Mar Freshw Res 62:676–693
Roff G, Doropoulos C, Rogers A, Bozec YM, Krueck NC, Aurellado E, Priest M, Birrell C, Mumby PJ (2016) The ecological role of sharks on coral reefs. Trends Ecol Evol 31:395–407
Rubio FC, Camacho FG, Sevilla JMF, Chisti Y, Grima EM (2003) A mechanistic model of photosynthesis in microalgae. Biotechnol Bioeng 81:459–473
Ryan LA, Lynch SK, Harcourt R, Slip DJ, Peddemors V, Everett JD, Harrison LM, Hart N (2019) Environmental predictive models for shark attacks in Australian waters. Mar Ecol Prog Ser 631:165–179
Sandin SA, Smith JE, DeMartini EE, Dinsdale EA, Donner SD, Friedlander AM, Konotchick T, Malay M, Maragos JE, Obura D, Pantos O, Paulay G, Richie M, Rohwer F, Schroeder RE, Walsh S, Jackson JBC, Knowlton N, Sala E (2008) Baselines and degradation of coral reefs in the Northern Line Islands. PLoS ONE 3:e1548
Sandulescu M, López C, Hernández-García E, Feudel U (2008) Biological activity in the wake of an island close to a coastal upwelling. Ecol Complex 5:228–237
Shabtay A, Lagabrielle E, Plot V, Potin G, Guyomard D (2020) Marine spatial planning provides a comprehensive framework for building evidence-based shark risk management policies with sea-users. Environ Sci Policy 111:18–26
Smoothey AF, Lee KA, Peddemors VM (2019) Long-term patterns of abundance, residency and movements of bull sharks (Carcharhinus leucas) in Sydney Harbour, Australia. Sci Rep 9:1–16
Soria M, Heithaus M, Blaison A, Crochelet E, Forget F, Chabanet P (2019) Residency and spatial distribution of bull sharks (Carcharhinus leucas) in and around Reunion Island MPA. Mar Ecol Prog Ser 630:101–113
Soria M, Jaquemet S, Trystram C, Chabanet P, Bourjea J, Jean C, Ciccione S, Dalleau M, Bigot L, Hemery A, Blaison A, Lemahieu A, Dulau V, Estrade V, Magalon H, Révillion C, Pennober G, Goutorbe S, Cambert H, Turquet J, Cotel P, Pirog A, Verlinden N (2015) Etude du comportement des requins bouledogue (Carcharhinus leucas) et tigre (Galeocerdo cuvier) à La Réunion. La Réunion, France
Suthers IM, Taggart CT, Rissik D, Baird ME (2006) Day and night ichthyoplankton assemblages and zooplankton biomass size spectrum in a deep ocean island wake. Mar Ecol Prog Ser 322:225–238
Taglioni F, Guiltat S, Teurlai M, Delsaut M, Payet D (2019) A spatial and environmental analysis of shark attacks on Reunion Island (1980–2017). Mar Policy 101:51–62
Thieurmel B, Elmarhraoui A (2019) suncalc: compute sun position, sunlight phases, moon position and lunar phase. https://cran.r-project.org/web/packages/suncalc/suncalc.pdf
Trystram C (2016) Ecologie trophique de poissons prédateurs et contribution à l’étude des réseaux trophiques marins aux abords de La Réunion. l’Université de La Réunion
Trystram C, Rogers KM, Soria M, Jaquemet S (2017) Feeding patterns of two sympatric shark predators in coastal ecosystems of an oceanic island. Can J Fish Aquat Sci 74:216–227
Trystram C, Roos D, Guyomard D, Jaquemet S (2015) Mechanisms of trophic partitioning within two fish communities associated with a tropical oceanic island. West Indian Ocean J Mar Sci 14:93–111
Villeneuve N, Bachèlery P, Kemp J (2014) La Réunion Island: a typical example of a basaltic shield volcano with rapid evolution. In: Fort M, André MF (eds) World Geomorphological Landscapes. Springer, Dordrecht, pp 261–270
Walton CC, Pichel WG, Sapper JF, May DA (1998) The development and operational application of nonlinear algorithms for the measurement of sea surface temperatures with the NOAA polar-orbiting environmental satellites. J Geophys Res Ocean 103: 27999–28012
Werdell PJ, Bailey SW (2005) An improved in-situ bio-optical data set for ocean color algorithm development and satellite data product validation. Remote Sens Environ 98:122–140
Wetherbee BM, Lowe CG, Crow GL (1994) A review of shark control in hawaii with recommendations for future research. Pacific Sci 48:95–115
White ER, Myers MC, Flemming JM, Baum JK (2015) Shifting elasmobranch community assemblage at Cocos Island-an isolated marine protected area. Conserv Biol 29:1186–1197
White JW, Samhouri JF (2011) Oceanographic coupling across three trophic levels shapes source-sink dynamics in marine metacommunities. Oikos 120:1151–1164
Wintner SP, Kerwath SE (2018) Cold fins, murky waters and the moon: what affects shark catches in the bather-protection program of KwaZulu-Natal, South Africa. Mar Freshw Res 69:167–177
Wolanski E, Delesalle B (1995) Upwelling by internal waves, Tahiti, French Polynesia. Cont Shelf Res 15:357–368
Wood SN (2017) Generalized Additive Models: An Introduction with R, 2nd edn. Chapman and Hall/CRC
Funding to YN through an International Macquarie University Research Training Program scholarship is deeply acknowledged. Funding to AW through the University of La Réunion from European Union’s Horizon 2020 research and innovation program (grant agreement no. 641762, ECOPOTENTIAL) and from the European Union’s FEDER (Regional Council of La Réunion, University of La Réunion) Fiche Action 1.16 “Renforcer l’effort en RDI des entreprises par le recrutement de jeunes diplômés”. EL contribution benefited from the Ocean Metiss project investigations funded by the European Commission through the European Maritime and Fisheries Fund (grant EASME/EMFF/2016/184.108.40.206/04/SI2.766484).
The relevant funding agencies have been acknowledged in the appropriate section, and we have no further ones to report.
Conflicts of interest
The authors declare no conflicts of interest.
Code availability (software application or custom code)
The moonlight index code (https://doi.org/https://doi.org/10.5281/zenodo.3971062) is publicly available together with a manual from https://github.com/YuriNiella/Moonlight-index.
Springer Nature remains neutral with regard to jurisdictional claims in published maps and institutional affiliations.
Reviewers: undisclosed experts.
Responsible Editor: J. Carlson.
Below is the link to the electronic supplementary material.
About this article
Cite this article
Niella, Y., Wiefels, A., Almeida, U. et al. Dynamics of marine predators off an oceanic island and implications for management of a preventative shark fishing program. Mar Biol 168, 42 (2021). https://doi.org/10.1007/s00227-021-03852-9