Since 2024, ElasmOcean has been supporting Lennart Vossgätter and Lukas Müller in their research on blue, shortfin mako and porbeagle sharks in the Bay of Biscay. The primary focus of this work is to investigate their habitat use and population dynamics in order to provide data for potential catch quotas and marine protected areas.
The first results are now available. A key question in this context: how and where in the Bay of Biscay do blue sharks actually mate? For some shark species, it is known that the animals swim parallel to each other for a short time until the male bites into a pectoral fin or the gills of the female, inserting its claspers for internal fertilisation. Such behaviour had never been observed in blue sharks – until now.
Since 2021, 17 females with bite marks have been sighted along the northern Spanish coast in the Bay of Biscay, where the slopes of the "Gouf de Capbreton" plunge to depths of approximately 1,000 metres just a few kilometres offshore. Now, putative mating behaviour has been captured on camera for the first time: in the case described, a young male blue shark attempted to mate with a subadult female (approx. 1.8 m). The female broke free and swam away, leaving the attempt unsuccessful. The published findings suggest that the Bay of Biscay could serve as a nursery ground for blue sharks.
We look forward to what further research will reveal.
Source: Vossgaetter et al. (2025): First documentation of putative mating behavior in blue sharks (Prionace glauca) reveals a potential reproductive area in the Northeast Atlantic. https://doi.org/10.5194/we-25-213-2025
