Recognizing Undulate Rays (Raja undulata)


Photographic techniques and analysis are used to identify individual undulate rays that return to a particular site over prolonged periods and over successive years.  We number each individual sighting of a ray so we felt that it would be appropriate to use letters for the individuals we identified.  That would only give us scope for twenty six individuals, so names starting with the letter of the alphabet, in order, became the method and injected the element of humour into the project.  The less obvious names have been explained.





“Al” was first seen in May 2013, shortly after starting this project.  He was notable for the number of scars that can be seen in the photograph; “surely these would remain at least partially distinct and distinguishable”.  He was named after Al Pacino – Scarface; but only seen again 2 ½ years later in August 2015. His scars have completely healed and are therefore no longer a distinguishing feature.





“Billy” was first identified as an individual in 2013 when he was seen and photographed on 3 successive occasions across a 2-month period from the end of June to the end of August.



He was named after Billy Bones from Robert Louis Stevenson’s Treasure Island because of a distinctive black spot on his left wing.  The spot is in the shape of a small rectangle with distinct right angular corners.  It does not look natural and is assumed to be an old wound although this has not been confirmed.  Billy is a mature male with a wingspan (disc diameter) of almost 50-cm and an overall length of approximately 90-cm.


Checking earlier records he was photographed on the same site in July 2012 and was subsequently photographed in August 2014.  Hence was in the vicinity or visited the same site over 3 consecutive years.  On at least 4 of the 5 occasions Billy has been seen, he has been at the same position to within less than 20 metres.  The record for the first sighting of Billy is less precise but is likely to have been in this same very close proximity.





Billy does not appear overly concerned about the presence of a diver.  On each occasion it has been possible to approach and take photographs, including placing a photographic scale close by.  After a few minutes the continued presence of the diver can cause him to slowly swim away, possibly settling again not too far away.  He was not seen in 2015.





Ray “Charles” was the role model used to develop the image processing sequence that allows individual rays to be identified from the patterns on the fish. He was seen and photographed twice on a single dive in September 2013. At the time, the second photograph of Charles was suspected to be of a fish seen earlier in the dive, however, conditions were not good and the resulting photographs were of poor quality. Although used to develop this process Charles has not been seen since, he is therefore the only ray to be named who has not been seen on more than one day.

                              "Charles" - as taken                                                             "Charles" - photo processed for ID



 “Dierdray” was seen on 3 separate occasions between 27th August and 3rd September 2013. She is a relatively large mature female, over 90-cm total length and 56%u2011cm across the disc width. On the first occasion she remained in the same area for over 3-hours being photographed on 2 separate occasions, 215 metres apart on the same day.

                                                                                                  "Dierdray" 11:20 am                  "Dierdray" 14:16 same day           



“Elanna” was first seen and photographed in September in 2013. The original set of photographs included a macro shot of a cling fish sitting on the ray’s wing hence the photograph and fish became known as “Klingons on the starboard bow”. She was seen again in July 2014, in approximately the same position, but, not having any clear distinguishing marks, it was not until the photographs were processed and compared that she was identified as the same fish. A Star Trek name was needed and after giving up on a bewildering internet search, where there’s far more technical information available on Star Trek trivia than on Raja undulata, we consulted a teenage boy who came up with “Elanna” after the character B’elanna Torres, who is, or was, or will be(?) half Klingon and half human, born in 2346 on the Federation colony Kessik IV.

               "Elanna" - September 2013                                  "Elanna" - July 2014




“Fraydo” has been photographed twice, a few days apart at the end of August and beginning of September 2013. He is the ray in the foreground of the photograph. This image is often used because, if you look closely, there is a second ray over toward the top left. His friend, has not been seen again, however, as this photo shows their camouflage is very effective and they can easily be missed, so we can’t say they were not there, we may simply have missed them. His name is probably obvious to anyone who has had children in the last 15 years or to those of us who read the Tolkien books as the primary hobbit.




“Garay” was seen twice in 2013 about 1-week apart. He was first photographed on the 27th August at about 11:30 am and then again by a different diver, on the same day at 15:30 pm. Comparison of the 2 photographs shows him to be in exactly the same position, i.e. he had not moved for over 4-hours. He is a large mature male, with a disc width of approximately 50-cm and an overall total length of 80-cm.


                                    "Garay" 11:30 AM                                                 "Garay" 15:30 - Same Day






“Harray” was seen and photographed on the same days as “Fraydo”, a few days apart at the end of August and beginning of September 2013. On both days and with both rays they were in a similar position on the overall site. Harray is named after Harry Stone, who we met in South Africa and spends his life watching and photographing sharks.










“Irayner” was photographedtwice  just four days apart at the end of August 2013.









“Juno” was photographed on 2 occasions in 2014 approximately one month apart. On the first occasion (August 2014) Juno was lying close to a larger ray; she was not noticed at the time and only seen in subsequent image where she shows, but not fully in the bottom left of the photograph. Being at the outer extent of the lens the image of her is also partially distorted. Initially it was thought impossible to achieve a good identification picture however, an attempt was made and included with the other images of both male and female fish, her sex being found from the first image. It was a surprise to be able to clearly match this with an image one month later in early September and provides additional confidence in the ability to match from partial images.


Juno takes her name from “Juno I saw another ray.”


                                                                                                     "Juno" August 2014                         "Juno" 1st September 2014


“Katiyanna” was seen on 2 occasions, 3 days apart in 2014, first on 4th August then again on the 7th August. She was noted at the time as a large fish and when measured against a scale was 62.5 cm across the disc width, giving an estimated total length of just over 1-metre. We were told that her name meant ‘of the sea’ which we felt was appropriate as she is a fish.

                              "Katiyanna" - 4th August 2014                                                                "Katiyanna" - 7th August 2014




“Lorayne” was seen on 2 occasions, firstly in September 2013 and again in August 2014. Although noted at the time as “a large ray”, the photographs do not include a scale hence it has not been possible to determine her actual size. In both cases she was in a similar position on the overall site.

                              "Lorayne" - August 2014                                                                "Lorayne" - September 2014






“Morayarty” was first seen in September 2014 and then twice again in both early and late June 2015.











“Nead” was seen twice in May and June 2015. The rays have been seen to back-up, effectively swimming backwards, or as they are all really skates, skating backwards. As Nead was travelling backward we decided it best to keep his partner’s name in the forward direction.








“Orayana” is a spotted ray (Raja montagui) not an undulate ray. She is the only fish from another ray species that has been individually identified on more than one day, being photographed on the 23rd and 27th August 2013. We see fewer spotted rays on the site and they are generally more skittish and hence more difficult to photograph.






“Persephone”, the Queen of the underworld, was first photographed in September 2014 and then again almost 1-year later in August 2015. She is easy to identify having an unusual black spot on her tail.












“Queray” was seen twice in August 2013 however it was not until late 2015, when first introducing using a computer program to identify matching photographs, that these were seen to be of the same fish. Although the decision as to whether two photographs are of the same fish is still made manually, the selection of potential duplicates by computer is much easier, especially if the photographs are of poor quality or at an unusual angle as was the case with Queray.





“Rey” was first seen on two separate days in September 2013 but like Queray, the match was not identified until the computer matching was introduced.

She was again seen 2 years later in June 2015, with numerous scars. These are possibly thought to be from vigorous mating activity. As we worked on the identification process, Star Wars episode 8 was released with an appropriately named major character. As the Jedi return we hope to see her again, and as the case with Al, the scars will have fully healed.


Stephanie (aka Stevie)



“Stephanie" is another fish first seen in August and September 2013 but with photographs not matched until the computer matching process was introduced. We were disappointed that the 19th fish identified was female, we had been hoping to name it after the Late Stevie Ray Vaughan, but an abbreviation of Stephanie is Stevie so we compromised.











“Torvill” is again a skate first seen in August and September 2013 but with photographs not matched until the computer matching process was introduced. She travels forward when her partner reverses.







The later part of the alphabet is the more difficult for finding names especially ones suitable for the correct gender. This ray’s name comes after a particularity difficult session “Uray – we have thought of one at last!”


She was first seen in July 2014, it was to be 14 months before she was next seen in September 2015.

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