In the seas around the UK about 21 different species of rays can be seen. Perhaps one of the most beautiful, the undulate ray, can be found around the south coast of the UK. These enigmatic creatures are unique to Western Europe, from the English Channel to the Moroccan coast. Although considered endangered from a global perspective, they are common in places along the south coast of the UK and each individual undulate ray can be identified from photographs of the unique pattern on their dorsal side - a technique pioneered for this species by the Undulate Ray project. Their behaviour has been observed in aquaria for decades, but we are only just learning about their life in the wild, and how it differs from captivity.
The Undulate Ray Project uses computer recognition of ray photographs to record their presence on the South Coast.
Data gathered initially from just one location in Dorset, has shown that undulate rays return to the same site over several years. Over a five-year period a database of photos with over 170 individual undulate rays was established and 25% of the rays had returned on more than one occasion. The undulate rays are not always on the same site, where they go is still a mystery.
In 2017 an appeal for photographs from divers and anglers of undulate rays along the Dorset coast was successful in highlighting that the original site is not unique. In the first 2 years the number of rays increased to over 700 with repeat sightings in several areas. However, out of all the submissions only 2 rays had travelled away from where they were originally seen. Undulate rays appear to be home loving creatures which could be vulnerable if subject to pressure in any one area.
The initial ray recognition technique was presented at the European Elasmobranch Association conference at Bristol in 2016 and led to an opportunity to assist wider research underway at Manchester University looking at the use of DNA to evaluate shark distributions. The undulate ray was one species under study in a PhD by Samantha Hook. She pioneered a swab technique for harvesting DNA from live rays without causing injury or distress (in fact it looks like they actually enjoy it). The project provided access to a population of undulate rays known to have visited a single site for over 5 years. DNA is extracted from mucus samples and analysis of the DNA will add to the understanding of undulate ray populations along the south coast.
Behavioural observations together with the data make us realise just how little we know about the lifestyle of the rays we interact with. We are making progress and hope to publish more information in the coming months.
There are many questions still to be answered, where do they go when they are not in the known locations; how far they travel; are they independent or remain as groups and where do rays lay their eggs? There are many theories to the last question, and we have different answers from aquaria data but very little data from the wild. Eggcases are washed up on our beaches, but where are they laid? This is another area where you can help, especially if you have underwater sightings, by contributing to The Great Eggcase Hunt, operated by The Shark Trust. More information will help to find out if there are specific breeding grounds for undulate rays.
Who operates the project? The Undulate Ray Project is operated by Martin and Sheilah from Stardis. They are assisted by marine ecologist and underwater photographer Matt Doggett. All genetics and DNA analysis is done by Samantha Hook.