The Marine Biological Association is a group.
A new study shows that circling behaviors of basking sharks can be seen as shark speed dating displays.
The circles of basking sharks seen off western Ireland are the first place in the world where this has been verified.
The circling formations in the north-west Atlantic have been documented a few times over the past 40 years.
The scientists captured footage of 19 circling groups using underwater cameras and aerial drones. Each group consisted of between six and 23 sharks swimming slowly at the surface, with others below them deeper down.
The sharks in the circle formations had the same number of males and females and were not filter-feeding. Females in other shark species have a different body color than males.
The study showed that individual females and males were associated with most other members within a few minutes. The sharks interacted with each other through touching, rolling, and breaching behavior, which may have been a sign of their readiness to mate.
The lead author of the study said, "How usually solitary basking sharks find a mate in the ocean's expanse has been an enduring mystery." The torus forms and acts like a slow motion'speed-dating' event for assessing lots of potential mates.
It is amazing that this wonder of the natural world has remained hidden for so long, perhaps because circles most often form at depth away from surface observation, which could explain why mating itself has never been seen.
Basking sharks can grow up to 12 meters in length and can eat zooplankton. They were hunted for oil and fins in the 20th century which reduced the population. Populations of Basking sharks are continuing to recover.
Dr. Simon Berrow of the Irish Basking Shark Group said, "Our discovery of important basking shark courtship grounds in coastal waters off western Ireland makes it even more urgent that this species gets protection in Irish waters from potential threats."
Legislation to protect basking sharks in Irish waters was only drafted this year. It will be illegal to hunt, hurt, or destroy their resting places if the law is signed.
The study was published in the journal of fish biology The research team hopes that their findings will lead to the identification of other basking shark courting grounds in the U.K. and elsewhere in the Mediterranean Sea and Pacific Ocean.
More information: David W. Sims et al, Circles in the sea: annual courtship "torus" behaviour of basking sharks Cetorhinus maximus identified in the eastern North Atlantic Ocean, Journal of Fish Biology (2022). DOI: 10.1111/jfb.15187 Journal information: Journal of Fish Biology Provided by Marine Biological Association
All Rights Reserved © 2024
