Environmental Biology of Fishes

, Volume 101, Issue 8, pp 1261–1268 | Cite as

Smooth hammerhead sharks (Sphyrna zygaena) observed off the Portuguese southern coast

  • Ana CoutoEmail author
  • Nuno Queiroz
  • James T. Ketchum
  • Eduardo Sampaio
  • Miguel Furtado
  • André A. Cid
  • Joana Castro
  • Rui Rosa


Despite its worldwide distribution and vulnerable status, knowledge on the biology and ecology of the smooth hammerhead Sphyrna zygaena in the temperate NE Atlantic is very scarce. Here, we reveal intra-annual fluctuations in S. zygaena abundance in the Portuguese southwestern coast, using sightings data collected on board whale watching boats over five years (2010–14; excluding winter months). Moreover, we investigated how shark abundance is related to local environmental conditions. We describe the first smooth hammerhead “hotspot” in the NE Atlantic, and we show a recurrent pattern of occurrence during the warmer summer and autumn months (from July to October) near Sagres and Martinhal Bay and islands. Intra-annual variations in abundance were significantly associated with sea surface temperature and negatively related with upwelling index and chlorophyll a, suggesting horizontal movements linked to the seasonal changes. Hence, hammerheads moved inshore during the warmer periods (with low primary productivity), due to either direct influence of temperature in their movements or indirect influence in prey distribution. This hammerhead “hotspot” may constitute a nursery ground for S. zygaena, nevertheless, our data does not allow us to prove or refute such claim. Future telemetry-based studies should be conducted to fully understand hammerhead movements and habitat preferences, and to evaluate this “hotspot” as a critical habitat for this predator.


Sea surface temperature Nursery ground Horizontal movements Seasonality 



The authors would like to thank CAPE CRUISER Company (located in Sagres) for the data collection. The Portuguese Foundation for Science and Technology (FCT) supported this study through Programa Investigador FCT 2013 – Development Grant to R. Rosa and the strategic project UID/MAR/04292/2013 granted to MARE.

Supplementary material

10641_2018_773_MOESM1_ESM.docx (74 kb)
ESM 1 (DOCX 73 kb)


  1. Afonso AS, Andrade HA, Hazin FH (2014) Structure and dynamics of the shark assemblage off Recife, Northeastern Brazil. PLoS One 9:e102369CrossRefPubMedPubMedCentralGoogle Scholar
  2. Bass AJ, D'Aubrey JD, Kistnasamy N (1975) Sharks of the East coast of Southern Africa. III. The families Carcharhinidae (excluding Mustelus and Carcharhinus) and Sphyrnidae South African Association for Marine Biological Research Oceanographic Research Institute Investigational ReportsGoogle Scholar
  3. Barreto R, Ferretti F, Flemming JM, Amorim A, Andrade H, Worm B, Lessa R (2016) Trends in the exploitation of South Atlantic shark populations. Conserv Biol 30:792–804. CrossRefPubMedGoogle Scholar
  4. Bezerra N, Macena BCL, Mendonca SA, Bonfil R, Hazin FHV (2017) First record of the smooth hammerhead shark (Sphyrna zygaena) in Saint Peter and Saint Paul archipelago: range extension for the equatorial region. Lat Am J Aquat Res 45:481–484. CrossRefGoogle Scholar
  5. Bornatowski H, Braga RR, Abilhoa V, Corrêa MFM (2014) Feeding ecology and trophic comparisons of six shark species in a coastal ecosystem off southern Brazil. J Fish Biol 85:246–263. CrossRefPubMedGoogle Scholar
  6. Bornatowski H, Costa L, Robert M de C, da PJV (2007) Hábitos alimentares de tubarões-martelo jovens, Sphyrna zygaena (Carcharhiniformes: Sphyrnidae), no litoral sul do Brasil. Biota Neotrop 7:213–216. CrossRefGoogle Scholar
  7. Buencuerpo V, Rios S, Moron J (1998) Pelagic sharks associated with the swordfish, Xiphias gladius, fishery in the eastern North Atlantic Ocean and the strait of Gibraltar. Fish Bull 96:667–685Google Scholar
  8. Casper BM et al. (2005) Sphyrna zygaena The IUCN Red List of Threatened Species Version 20152 <> Downloaded on 23 June 2015
  9. Coelho R, Fernandez-Carvalho J, Amorim S, Santos MN (2011) Age and growth of the smooth hammerhead shark, Sphyrna zygaena, in the eastern equatorial Atlantic Ocean, using vertebral sections. Aquat Living Resour 24:351–357. CrossRefGoogle Scholar
  10. Coelho R, Fernandez-Carvalho J, Lino PG, Santos MN (2012) An overview of the hooking mortality of elasmobranchs caught in a swordfish pelagic longline fishery in the Atlantic Ocean. Aquat Living Resour 25:311–319. CrossRefGoogle Scholar
  11. Compagno LJV (1984) FAO Species catalogue, Vol. 4. Sharks of the World; an annotated and illustrated catalogue of shark species known to date. Part 2. Carcharhiniformes. FAO Fish Synop 125:250–655Google Scholar
  12. Correia JP (2009) Commercial fishing of sharks and rays in Portugal (in Portuguese). PhD thesis, Departamento de Biologia, Universidade de Aveiro, p 402Google Scholar
  13. Couto A, Baptista M, Furtado M, Sousa L, Queiroz N (2016) Life histories of Oceanodromous fishes. An Introd to Fish Migr 123–146 . doi:
  14. Cunningham RB, Lindenmayer DB (2005) Modeling count data of rare species: some statistical issues. Ecology 86:1135–1142CrossRefGoogle Scholar
  15. Diemer KM, Mann BQ, Hussey NE (2011) Distribution and movement of scalloped hammerhead Sphryna lewini and smooth hammerhead Sphyrna zygaena sharks along the east coast of southern Africa. Afr J Mar Sci 33:229–238. CrossRefGoogle Scholar
  16. Doño F (2008) Identificación y caracterización de áreas de cría del tiburón Martillo (Sphyrna spp.) en las costas de Uruguay. Tesis de Licenciatura, Facultad de Ciencias, Universidad de la República de UruguayGoogle Scholar
  17. Dudley SF, Cliff G (2010) Influence of the annual sardine run on catches of large sharks in the protective gillnets off KwaZulu-Natal, South Africa, and the occurrence of sardine in shark diet. Afr J Mar Sci 32:383–397CrossRefGoogle Scholar
  18. 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 57:225–240CrossRefGoogle Scholar
  19. Francis M (2016) Distribution, habitat and movement of juvenile smooth hammerhead sharks (Sphyrna zygaena) in northern New Zealand. N Z J Mar Freshw Res 50:506–525CrossRefGoogle Scholar
  20. García-Reyes M, Sydeman WJ, Schoeman DS, Rykaczewski RR, Black BA, Smit AJ, Bograd SJ (2015) Under pressure: climate change, upwelling, and eastern boundary upwelling ecosystems. Front Mar Sci 2:109CrossRefGoogle Scholar
  21. Hastie T (2013) gam: Generalized Additive Models, R Package, version 0.98 URL
  22. Hearn A, Ketchum J, Klimley AP, Espinoza E, Penaherrera C (2010) Hotspots within hotspots? Hammerhead shark movements around Wolf Island, Galapagos marine reserve. Mar Biol 157:1899–1915. CrossRefPubMedPubMedCentralGoogle Scholar
  23. Heupel MR, Carlson JK, Simpfendorfer CA (2007) Shark nursery areas: concepts, definition, characterization and assumptions. Mar Ecol Prog Ser 337:287–297CrossRefGoogle Scholar
  24. Ketchum JT, Hearn A, Klimley AP, Espinoza E, Peñaherrera C, Largier JL (2014) Seasonal changes in movements and habitat preferences of the scalloped hammerhead shark (Sphyrna lewini) while refuging near an oceanic island. Mar Biol 161:755–767. CrossRefGoogle Scholar
  25. Klimley A, Butler S (1988) Immigration and emigration of a pelagic fish assemblage to seamounts in the Gulf of California related to water mass movements using satellite imagery. Marine Ecol Prog Ser Oldendorf 49:11–20CrossRefGoogle Scholar
  26. Klimley AP, Butler SB, Nelson DR, Stull AT (1988) Diel movements of scalloped hammerhead sharks, Sphyrna lewini Griffith and Smith to and from a seamount in the Gulf of California. J Fish Biol 33:751–761CrossRefGoogle Scholar
  27. Klimley AP, Nelson DR (1984) Diel movement patterns of the scalloped hammerhead shark (Sphyrna lewini) in relation to El Bajo Espiritu Santo: a refuging central-position social system. Behav Ecol Sociobiol 15:45–54CrossRefGoogle Scholar
  28. Koslovsky S, Halpin P, Read A (2008) Wandering whale watches: the effectiveness of whale watches as a platform of opportunity for data collection unpublished MSc thesis. Durham, Duke UniversityGoogle Scholar
  29. Peliz A, Dubert J, Santos AMP, Oliveira PB, Le Cann B (2005) Winter upper ocean circulation in the western Iberian Basin - fronts, eddies and poleward flows: an overview. Deep-Sea Res Part I-Oceanograph Res Papers 52:621–646CrossRefGoogle Scholar
  30. Smale MJ (1991) Occurrence and feeding of three shark species, Carcharhinus brachyurus, C. obscurus and Sphyrna zygaena on the Eastern Cape coast of South Africa. S Afr J Mar Sci 11:31–42CrossRefGoogle Scholar
  31. Southall EJ, Sims DW (2005) A smooth hammerhead shark (Sphyrna zygaena) from south-west England JMBA2 - Biodiversity Records (published online):1–2Google Scholar
  32. Stratoudakis Y, Coombs S, de Lanzós AL, Halliday N, Costas G, Caneco B, Franco C, Conway D, Santos MB, Silva A, Bernal M (2007) Sardine (Sardina pilchardus) spawning seasonality in European waters of the northeast Atlantic. Mar Biol 152:201–212CrossRefGoogle Scholar
  33. Vooren CM, Klippel S, Galina AB (2005) Biologia e status conservação dos tubarão-martelo Sphyrna lewini e S. zygaena. In: Vooren CM, Klippel S (eds) Ações para a conservação de tubarões e raias no sul do Brasil. Igaré, Porto Alegre, pp 97–112Google Scholar
  34. Wood S (2006) Generalized additive models: an introduction with R. Chapman and Hall/CRC, Boca RatonGoogle Scholar
  35. Wood S, Wood MS (2017) Package ‘mgcv’ R package version:1.7–29Google Scholar

Copyright information

© Springer Science+Business Media B.V., part of Springer Nature 2018

Authors and Affiliations

  1. 1.MARE – Marine and Environmental Sciences Centre, Laboratório Marítimo da GuiaUniversidade de LisboaCascaisPortugal
  2. 2.CIBIO/InBIOUniversidade do PortoVairãoPortugal
  3. 3.Centro de Investigaciones Biológicas del Noroeste (CIBNOR)La PazMexico
  4. 4.Pelagios Kakunjá A.C.La PazMexico
  5. 5.Associação para a Investigação do Meio MarinhoLisbonPortugal

Personalised recommendations