PREVIOUS INFO

The killer whales of the Strait of Gibraltar are considered distinct from other subpopulations in the Northeast Atlantic, based on studies of photo-identification data, mitochondrial DNA, microsatellite genetic markers, stable isotope ratios and contaminant loads (Esteban et al. 2016a). This small subpopulation, with a low number of mature individuals, depends heavily on an endangered prey species, the Atlantic bluefin tuna (García-Tíscar 2009). Even though adult survival rates were estimated within levels known to be consistent with stable populations, long-term poor recruitment suggests an inferred decline in the future unless conditions improve (Esteban et al. 2016b). For these reasons, this subpopulation of killer whales were catalogued as vulnerable by the Spanish Ministry of Environment in 2011 (R.D. 139/2011), which then published a conservation plan in 2017 (APM/427/2017), and were assessed as Critically Endangered by the IUCN Red List in 2019 (Esteban and Foote 2019). Typically in the Strait of Gibraltar the killer whales are observed either actively chasing tuna until exhaustion (Guinet et al. 2007), or depredating tunas caught by long-line fishing boats (Esteban et al. 2016b).

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REFERENCES

Esteban, R., Verborgh, P., Gauffier, P., Giménez, J., Martín, V., Pérez-Gil, M., Tejedor, M., Almunia, J., Jepson, P. D. P. D., García-Tiscar, S., Barrett-Lennard, L. G., Guinet, C., Foote, A. D. , and de Stephanis, R., (2016a). Using a multi-disciplinary approach to identify a critically endangered killer whale management unit. Ecological Indicators, 66, 291–300. https://doi.org/10.1016/j.ecolind.2016.01.043

 

Esteban, R., Verborgh, P., Gauffier, P., Giménez, J., Guinet, C., and de Stephanis, R. (2016b). Dynamics of killer whale, bluefin tuna and human fisheries in the Strait of Gibraltar. Biological Conservation, 194, 31–38. https://doi.org/10.1016/j.biocon.2015.11.031

 

Esteban, R. and Foote, A. 2019. Orcinus orca (Strait of Gibraltar subpopulation). The IUCN Red List of Threatened Species 2019: e.T132948040A132949669. https://dx.doi.org/10.2305/IUCN.UK.2019-3.RLTS.T132948040A132949669.en.

García-Tiscar, S. 2009. Interacciones entre delfines mulares y orcas con pesqeuerías en el Mar de Alborán yestrecho de Gibraltar. PhD thesis. Universidad Autónoma de Madrid, España. 

Guinet, C., Domenici, P., De Stephanis, R., Barrett-Lennard, L., Ford, J. K. B., andVerborgh, P. (2007). Killer whale predation on bluefin tuna: Exploring the hypothesis of the endurance-exhaustion technique. Marine Ecology Progress Series, 347, 111–119. https://doi.org/10.3354/meps07035

 

Orden APM/427/2017, de 4 de mayo, por la que se aprueban las medidas de protección, y el Plan de Conservación de las orcas del Estrecho y Golfo de Cádiz.

Real Decreto 139/2011, de 4 de febrero, para el desarrollo del Listado de Especies Silvestres en Régimen de Protección Especial y del Catálogo Español de Especies Amenazadas.

FURTHER READING

de Stephanis, R., Giménez, J., Esteban, R., Gauffier, P., García-Tiscar, S., Sinding, M.-H., and Verborgh, P. (2015). Mobbing-like behavior by pilot whales towards killer whales: a response to resource competition or perceived predation risk? Acta Ethologica, 18(1), 69–78. https://doi.org/10.1007/s10211-014-0189-1

Esteban, R., Verborgh, P., Gauffier, P., Giménez, J., Afán, I., Cañadas, A., García, P., Murcia, J. L., Magalhães, S., Andreu, E., and de Stephanis, R. (2014). Identifying key habitat and seasonal patterns of a critically endangered population of killer whales. Journal of the Marine Biological Association of the United Kingdom, 94(6), 1317–1325. https://doi.org/10.1017/S002531541300091X

Esteban, R., Verborgh, P., Gauffier, P., Alarcón, D., Salazar-Sierra, J. M., Giménez, J., Foote, A. D., and de Stephanis, R. (2016). Conservation Status of Killer Whales, Orcinus orca, in the Strait of Gibraltar. Advances in Marine Biology. https://doi.org/10.1016/bs.amb.2016.07.001

Esteban, R., Verborgh, P., Gauffier, P., Giménez, J., Foote, A. D., and de Stephanis, R. (2016). Maternal kinship and fisheries interaction influences killer whale social structure. Behavioral Ecology and Sociobiology, 70(1), 111–122. https://doi.org/10.1007/s00265-015-2029-3

 

Foote, A. D., Vilstrup, J. T., de Stephanis, R., Verborgh, P., Abel Nielsen, S. C., Deaville, R., Kleivane, L., Martín, V., Miller, P. J. O., Oien, N., Pérez-Gil, M., Rasmussen, M., Reid, R. J., Robertson, K. M., Rogan, E., Similä, T., Tejedor, M., Vester, H., Víkingsson, G. A., … Piertney, S. B. (2011). Genetic differentiation among North Atlantic killer whale populations. Molecular Ecology, 20(3), 629–641. https://doi.org/10.1111/j.1365-294X.2010.04957.x

Foote, A. D., Martin, M., Louis, M., Pacheco, G., Robertson, K., Sinding, M.-H., Amaral, A., Baird, R., Baker, S., Ballance, L., Barlow, J., Brownlow, A., Collins, T., Constantine, R., Dabin, W., Rosa, L. D., Davison, N., Durban, J., Esteban, R.,  Morin, P. (2019). Killer whale genomes reveal a complex history of recurrent admixture and vicariance. BioRxiv, April, 520718. https://doi.org/10.1101/520718

Jepson, P. D., Deaville, R., Barber, J. L., Aguilar, A., Borrell, A., Murphy, S., Barry, J., Brownlow, A., Barnett, J., Berrow, S., Cunningham, A. A., Davison, N., Doeschate, M., Esteban, R., Ferreira, M., Foote, A. D., Genov, T., Giménez, J., Loveridge, J., et al. (2016). PCB pollution continues to impact populations of orcas and other dolphins in European waters. Scientific Reports, 6, 18573. https://doi.org/10.1038/srep18573

Mäkeläinen, P., Esteban, R., Foote, A. D., Kuningas, S., Nielsen, J., Samarra, F. I. P., Similä, T., van Geel, N. C. F., and Vikingsson, G. A. (2014). A comparison of pigmentation features among North Atlantic killer whale (Orcinus orca) populations. Journal of the Marine Biological Association of the United Kingdom, 94, 1335–1341. http://journals.cambridge.org/abstract_S0025315414000277

 

Otero-Sabio, C., Morale-Herrera, T., Escobar-Casado, J. M. M., & Andreu-Cazalla, E. (2018). Avistamiento de cetáceos como herramienta para el estudio de la población de orca (Orcinus orca) en el Estrecho de Gibraltar. Chronica Naturae, 7, 27–36. https://dialnet.unirioja.es/descarga/articulo/6339565.pdf