A Year’s Worth of Results

SURVEYING DUBAI WATERS FOR SMALL CETACEANS

FEATURE BRYANA COPE & ADA NATOLI – UAE DOLPHIN PROJECT INITIATIVE & ZAYED UNIVERSITY PHOTOGRAPHY

An Indo-Pacific Finless Porpoise exhibiting the unusual white frontal dorsal colouration.

Ada Natoli – UAE Dolphin Project

Indo-Pacific Bottlenose Dolphins, mother and her calf.

Ada Natoli – UAE Dolphin Project

An Indo-Pacific Bottlenose Dolphin in clear feeding behaviour.

Ada Natoli – UAE Dolphin Project

Another Indo-Pacific Finless Porpoise exhibiting the dark dorsal colouration.

Ada Natoli – UAE Dolphin Project

A juvenile Bottlenose Dolphin performing a backward leap.

Ada Natoli – UAE Dolphin Project

After one year of surveying Dubai waters, the UAE Dolphin Project initiative and Zayed University have produced some interesting and vital results. The survey started in February of 2021 with the main objective to collect data to assess the population of Indian Ocean humpback dolphins, Indo-Pacific bottlenose dolphins, and Indo-Pacific finless porpoises.A transect survey method was used in order to evenly search from Port Rashid to the Jebel Ali Marine Sanctuary, and 20km offshore. Multiple types of data was collected during each outing, including environmental data, water quality, behavioural and photo identification data when encountering the animals. Throughout the year, 60 surveys were conducted totalling 272.5 hours of positive navigation, and 5,443.91km. Overall 18 sightings of small cetaceans, 12 sightings of bottlenose dolphins, and 6 sightings of finless porpoises were recorded for a total of 250 individuals overall.A worrying outcome of the survey was the absence of the Indian Ocean humpback dolphins, that during the past survey in 2014 was among the species most frequently observed in the area.This species is listed as “Endangered” by the IUCN Red List as its decline has been observed across all its geographic range.

Water quality data was collected throughout the year and used to identify seasonal changes. There was a spike in temperature in mid-May which went back down in November. Thus, summer was defined as mid-May to midNovember, and winter as mid-November to mid-May. The average water temperature for summer was 34°C, and 26.36°C in the winter. This could be the reason there were only 4 sightings during the summer, but more data will need to be collected to determine this.

Photographic information of the dolphin and porpoises encountered was the important data collected during the sightings. Over 11,000 photos were collected across the 18 encounters. During each sighting, pictures of the dorsal fin of all individuals present were collected. Individual dolphins are recognisable from the shape, nicks and scars on their dorsal fin that works like a natural tag. So, analysing and matching the pictures in each sighting – across sightings and across years –scientists can estimate how many individuals were actually present in the group, how many individuals were resighted across sightings, and how frequently. Furthermore, it is possible to estimate the social structure of the groups, tracking the frequency of the same individuals occurring in the same group. Ultimately, matching individuals to a previous year’s Photo Identification catalogue, created during the 2014 survey, it is possible to understand whether these groups are actually long-term residents.

There were quite a few sightings of the same individuals throughout the year. This indicates that the population is likely to be small, as the greater the population, the less likely it is to sight the same individuals repeatedly. Several individuals were sighted in the same sighting and in multiple sightings, and some individuals were sighted with associated young.We were also able to match 14 individuals so far with the 2014 catalogue, suggesting that the same group is regularly using Dubai waters on a long-term basis, across 8 years! This number is likely to increase once the process of sorting and matching the photos is concluded.

During the 18 sightings, the team spent a total of 24 hours with the animals, during which behavioural data was also collected. Using the field estimates, group composition was calculated to show that total sightings consisted of 80% adults, 13% juveniles and 7% calves. For bottlenose dolphins, the majority of the time the groups were seen travelling (80%) but were also observed socialising (9%) and feeding (2%). Finless porpoises were also observed mainly travelling (60%) but also feeding (17%). This may indicate that finless porpoises use the area more for feeding than bottlenose dolphins, or that we couldn’t observe the bottlenose dolphins feeding if they were hunting in deeper waters where we can’t identify the behaviour. Finless porpoises were mainly observed inshore, most frequently between The World Islands and the mainland. On the other hand, bottlenose dolphins were observed mainly offshore. This suggests that both the inshore and offshore areas of Dubai are vital to the habitat of both species.

A volunteer assisting in data collection duing a survey.

Ada Natoli – UAE Dolphin Project

A juvenile and 2 adult Socotra cormorants flying in proximity of The World Islands.

Ada Natoli – UAE Dolphin Project

Green turtles mating.

Ada Natoli – UAE Dolphin Project

A blacktip reef shark.

Ada Natoli – UAE Dolphin Project

Sea snakes mating.

Ada Natoli – UAE Dolphin Project

A juvenile Hawksbill turtle rescued by the team during a survey.

Ada Natoli – UAE Dolphin Project

Although finless porpoises do not have a dorsal fin, photographic information was used mainly to confirm the species and the presence of calves. However, interestingly the colouration observed was not a usual colouration for finless porpoises compared worldwide. Both calves and adults had a characteristic white colouration on the underside of the body, underneath the mouth. This colour has been seen in Kuwait and further comparisons with the worldwide populations to investigate this characteristic is in progress.

Citizen science data collection was another important source of information. As the team can only go out so many times, it is vital that citizens report their sightings so data can be expanded on. Over the course of the year, 92 sightings were reported from the public and have been validated by experts, out of 74 of those sightings, a species has been confirmed. These included the three main species as well as a few rare species. We reported on these in the last issue as they were very exciting! A pod of killer whales seen offshore, a Bryde’s whale in Dubai Marina Harbour, as well as an additional Bryde’s whale and a false killer whale. This data is vital to showing just how many species occur in Dubai waters! Thank you again to all who have reported your sightings and please keep sending them in to us at sightings@uaedolphinproject.org. We couldn’t get these results without you!

The survey also allowed us to collect crucial data on other important marine megafauna: Socotra cormorants, sea turtles and sea snakes. There were a handful of sightings of sharks, rays and other rare birds as well. Overall there were 589 sightings of Socotra cormorants, some sightings had thousands of birds, and some as little as just one.There were 68 sightings of sea turtles, some of which were observed mating, along with 153 sightings of sea snakes who were also observed mating a number of times! The team also rescued a small Hawksbill turtle that was covered in barnacles and unable to swim. The turtle was taken to the Dubai Turtle Rehabilitation Project.You can report any stranded turtles to them at 800-Turtle!

All this data provided information to better identifying key areas of habitat use for all the species recorded. Sea turtles were observed throughout the entire survey area, whereas sea snakes were most often seen offshore, and Socotra cormorants were mainly observed inshore. They also confirmed that Dubai waters are important habitats for a variety of species both for feeding and breeding. This data is currently being reviewed and analysed for multiple scientific papers by the lead researcher, Dr Ada Natoli and will be vital to showcasing the importance of protecting these waters for generations of multiple marine species.

After a very successful year, the UAE Dolphin Project initiative is continuing to survey the area with hopes of expanding even further offshore and north to Deira. We hope that you continue to support the project in any capacity that you can.

WHAT YOU CAN DO TO HELP

REPORT YOUR SIGHTINGS AT: www.uaedolphinproject.org Or via Facebook, Instagram, Whatsapp on 050 955 1742,or Call on 056 671 7164

To join the ResearchTeam, you can email us at: team@uaedolphinproject.org

THANK YOU

A big thank you to our sponsors of the 2021-2022 survey, Atlantis the Palm, F3 Marine and Zayed University, and to the Emirates Diving Association for continuing to highlight our project in their magazine!