Looking for the migratory whales: Routes of the baleen whales in the Macaronesia
Valente, R.F. (2017). Looking for the migratory whales: Routes of the baleen whales in the Macaronesia. MA Thesis. Faculdade de Ciências da Universidade do Porto (FCUP): Porto. 114 pp. |  |
| Keywords | Behaviour > Migrations
Mysticeti Flower, 1864 [WoRMS]
| | Author keywords | Baleen whales, Macaronesia, Spatio-temporal patterns, Habitat Preference, Geomagnetism |
| Abstract | Baleen whales play a key role in marine ecosystems. Being top predators, this group of animals is fundamental in top-down regulation and thus in the preservation of biodiversity. In addition, they are migratory animals, crossing long distances between summer feeding grounds in upper latitudes and tropical winter grounds for mating and breeding. Being such mobile animals, it is fundamental to know their distribution, in order to implement the necessary measures for the conservation and protection of these animals. In the Northeast Atlantic, there are several species of baleen whales that cross the region of Macaronesia during their migrations. However, very little is known about their movements throughout the area because much of the information regarding the presence of these cetaceans is highly scattered and mainly restricted to areas near the coast. With all this in mind, this study aimed to understand spatial-temporal patterns in the migrations of four species of baleen whales (minke, fin, blue and humpback whales), using sightings from publication and databases. Spatio-temporal analysis were carried out in order to obtain a more concrete idea of possible migratory routes in the area. Posteriorly, with the occurrences of collected individuals, we investigate possible habitat preferences. Finally, a possible correlation between geomagnetism and migratory paths was explored. From a total of 15 articles, 3 reports, 1 conference proceeding and 4 databases, we gathered 1797 sightings of baleen whales in Macaronesia. The results show a clear difference in the distribution of minke and fin whales compared to the blue and humpback whales, most likely due to the existence of resident populations for the former two. It is also suggested the existence of at least 2 migratory routes in the Macaronesia: both are on the high seas, but while one passes through the Azores, the other will pass through "saharan" waters. The analysis of habitat preferences suggests that whales use both oceanographic phenomena and the topography of the oceans to feed opportunistically during their migrations. Regarding geomagnetism, although it has not been possible to demonstrate its use during migrations, it is definitely shown the potential of certain magnetic components as means of orienting the whales when they are migrating. Finally, this study demonstrated once again the need to obtain more data in offshore areas to implement measures that will effectively protect this group of cetaceans. |
| Dataset | - Correia, A.M., Oliveira-Rodrigues, C., Gandra, M., Liberal, M., Valente, R., Gil, A., Rosso, M., Pierce, G.J. & Sousa-Pinto, I., CIIMAR - UP. (2022). CETUS: Cetacean monitoring surveys in the Eastern North Atlantic. Marine Data Archive., more
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