A tale of two seas: Last Ice Age has shaped sharks across Europe
This depicts a catshark resting in the daytime. Credit: David Sims
Many previous studies on sharks suggest they move over large distances. But catsharks in the Mediterranean Sea appear to move and migrate much less, as revealed by this study. This could have important implications for conserving and managing sharks more widely, suggesting they may be more vulnerable to over-fishing than previously thought.
The study, published in the new journal Royal Society Open Science, used genetic techniques to investigate the population structure of the small-spotted shark, Scyliorhinus canicula. The species is common throughout Europe and has been eaten since ancient times, as documented in Roman mosaics.
In the UK anglers catch it for sport and it can often be seen in rock pools at low tide. The study found evidence of isolated populations in the Mediterranean, but no population division was found between catsharks around the North East Atlantic and British Isles.
During the last ice age, about 20,000 years ago, ice sheets occupied much of the Seas and Ocean of this region and catsharks probably didn't survive in the area. This means the region had to be recolonised, and there are very little genetic differences between them today.
The study also highlights differences in the movements of males and female catsharks – an increasingly common finding in sharks.
Dr Griffiths, based in the School of Biological Sciences, said: “It makes a lot of sense, females may want to stay in areas that are good for laying eggs, but males are often the dispersing sex, perhaps taking risks to increase how much they reproduce.”
This research has conservation implications; if patterns of population structure vary hugely in different seas, and between the sexes, then shark resilience to fishing can vary greatly, meaning that better informed management could be needed for many species.
Paper
'A tale of two seas: contrasting patterns of population structure in the small-spotted catshark across Europe' by Gubili C et al in Royal Society Open Science.
Media Contact
All latest news from the category: Earth Sciences
Earth Sciences (also referred to as Geosciences), which deals with basic issues surrounding our planet, plays a vital role in the area of energy and raw materials supply.
Earth Sciences comprises subjects such as geology, geography, geological informatics, paleontology, mineralogy, petrography, crystallography, geophysics, geodesy, glaciology, cartography, photogrammetry, meteorology and seismology, early-warning systems, earthquake research and polar research.
Newest articles
Trotting robots reveal emergence of animal gait transitions
A four-legged robot trained with machine learning by EPFL researchers has learned to avoid falls by spontaneously switching between walking, trotting, and pronking – a milestone for roboticists as well…
Innovation promises to prevent power pole-top fires
Engineers in Australia have found a new way to make power-pole insulators resistant to fire and electrical sparking, promising to prevent dangerous pole-top fires and reduce blackouts. Pole-top fires pose…
Possible alternative to antibiotics produced by bacteria
Antibacterial substance from staphylococci discovered with new mechanism of action against natural competitors. Many bacteria produce substances to gain an advantage over competitors in their highly competitive natural environment. Researchers…
