• Leanne Rosser

Dolphin Season 2022: From Mutsu to the Pacific

I'm back in Osaka after my last fieldwork trip as a resident of Japan. The trip was filled with dolphins, science chats, outreach, as well as an extra adventure on the Pacific Ocean to finish things off. With only a month or so left in this beautiful country I've called home for five and a half years, this year's research season was even more memorable.

Dolphin watching with Wakinosawa Primary School

Our work began with a guided tour on a sightseeing boat, leading the children of Wakinosawa primary school out to see the dolphins. Our research surveys are conducted aboard local fisherman Tanaka-san's boat but there is also a small tourist boat that runs trips to see the dolphins during this season. The weather was cloudy and cold but neither the dolphins nor kids seemed to mind. They were full of curiosity and fascination, asking such thought-provoking questions as 'do dolphins get tooth cavities?'

This year was the first time since before the pandemic that we could have a full research team. One of our core members (Mie University associate professor) could finally return to Aomori and was joined by Tokyo University of Marine Science and Technology assistant professor, both of whom specialise in cetacean acoustic work. After a two year hiatus, students could finally gain fieldwork experience with us again, and this season we were joined by two master’s students from the two universities.

Some of the team at work

The team tried to record the dolphins' feeding communication sounds using a hydrophone as well as capture their feeding behaviour with cameras. In the evenings the director's house became a research hub and the team would discuss science, dolphins, project goals and our next papers over beers. This season I also had my first experience as a dolphin watching tour guide. A group of American Girl Scouts had travelled to Wakinosawa from their home in Misawa, Aomori, to see the dolphins and learn more about Mutsu Bay Dolphin Research's work.

Teaching the kids about Pacific white-sided dolphins

As with any wildlife research, especially at sea, the weather plays a huge part. With unusually strong winds for June rolling in, boat surveys were cancelled for three days. Although it was disappointing to lose out on days of data collection, 'しょうがない' (shouganai; it can't be helped) as the Japanese would say. We made the most of our time on land by giving a presentation back at Wakinosawa primary school, teaching the kids all about our work. These kids are so interested in the dolphins that visit their hometown every spring and had all prepared some super smart questions. We also made local news! A reporter came to interview me about our recent paper and the article was featured in the newspaper.

Our final survey in Mutsu Bay was fantastic. After getting off to a worrying start where we were unable to locate the dolphins, we were treated to some socialising behaviours under the shining sun. My job as a photo-ID researcher can prove very difficult when the dolphins are in such playful moods. As the dolphins enjoyed some bow riding, one individual tilted to the side and we locked eyes in what seemed like a moment of mutual curiosity. It was the perfect way to say goodbye to our study site (hopefully only for a year).

This year we added some preliminary research, making the 8 hour drive along the Pacific coast to Miyagi prefecture for a survey with Minami-sanriku Nature Centre. Part of our long-term project is to help understand Pacific white-sided dolphin migration patterns around Japan. Through our photo-ID work we hope to compare with other areas and piece together any clues of where our Mutsu Bay dolphins might come from/leave to. Minami-sanriku was one of the towns devastated by the 2011 tsunami and its mark can be seen everywhere. The nature centre itself was also damaged, losing all of their collected marine specimens. However today, in the spirit of recovery representative of the entire area, they have collected thousands more than they once had. For the duration of our short stay here we were accommodated by a sustainability scientist from the nature centre, his lovely wife and their gorgeous old dog. Having met the couple two years earlier when living in Aomori, it was wonderful to spend time with them again.

Our lovely hosts

Our work in Miyagi began early in the morning aboard a local fisherman's boat. Unlike Mutsu Bay where these dolphins can be observed shortly after leaving the harbour, we had to travel for an hour and a half out into the Pacific Ocean before finding our first group. The conditions were perfect and even the dolphins were being cooperative, getting close enough to take some great ID-shots. It was really exciting for me to observe our study species in another location, to try and gain any new information of how this species behaves in more open waters. We were also lucky enough to spot a blue shark and three species of albatross. Later that evening, we were invited to give a talk to members of the local community. I discussed my recent paper on the potential infanticide attempt in Mutsu Bay and we showed the audience drone footage from that day’s survey. Nobody had ever seen wild Pacific white-sided dolphins so they were amazed that the video was shot in the ocean beside their town.

After such a memorable trip I have a lot of fins to sort through! Whether I will return to Aomori next year is dependent on grant money but my dolphin journey is about to take a sharp turn as I embark on a master's degree in the UK. I hope to get started on some research in British waters, however my work in Japan will still continue, as will my devotion to the project here.

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