Mikura 2004 Field Summary

Our Season was VERY Productive with much data collected. Twenty boat trips were provided for me to gather data on the dolphins. During this time we spent 38 hours, 31 minutes searching for and observing dolphins from which I was able to record more than 7.5 hours of video. This is about a 19.5% return on effort – the highest of any field season around Mikura for DCP. There were 92 sightings of dolphin groups with a range of 1-8 per trip and a trip median of 4 sightings.

Departure from Mikura Island

The ferry was cancelled in the morning, leaving me concerned for the afternoon. The return trip to Tokyo from Mikura was uneventful but very full of people. About 400 tourists returned from Hachijo Island and about 100 from Mikura. Today marked the end of a holiday weekend in Japan: Marine Day. That is, 19 July is “Umi no hi” – A day in celebration of the oceans. As far as I know, Japan is the only country to have a special day celebrating the oceans. The previous emperor was an avid amateur marine biologist.

Packing, Packing, Packing

And, cleaning of the house I rented for the 7 weeks I was here. I successfully refit everything into my large travel case. The array is well padded and packed. My wet suit (now dry) and mask, fins and snorkel fit inside the same box. First time I have been able to get everything into one case in terms of my research gear.

The data – 20 tapes in total (10 ECD and 10 video) will be hand-carried with me, as will the data sheets and the ID sketches per dolphin.

A Day of Cleaning and Preparing Gear

Today was a slow day that saw the wind increase Today was a slow day that I spent breaking down my array and soaking parts in fresh water then drying them. I sorted gear, clothing and data in preparation for packing.

I also visited a few folks on the island to say thank you for their help and for welcoming me again to their island home. I dropped off thank you letters to the school and said bye to the teachers till next year.

Likely, My Last Boat Trip for the Season

The sea condition is worsening and we are coming to a weekend (i.e., many tourists). I filled the last space on the trip with Michio this afternoon. There were three other watching boats out and several fishermen. The wind and sea were up but we saw dolphins between Motone and Shirataki. We had four sightings of about 8-12 dolphins per group. A sub-adult male group, a female sub-adult group, a mixed group and then that went undetermined as we did not stop to observe them under water.

In Port Day

As the day progressed, the sea calmed and the air temperature rose. The old pier is about 150 meters long and they are adding another 30 m to it this month. The construction has been interesting to watch over the past 7~8 weeks. There are two sections of pier at Mikura's port: the old pier was built in sections and took ~30 years from start to this point and the new pier which took about 6 years (so far).

In Port Today – a fierce wind greeted us this morning.

I was almost grateful of the wind because it meant that my body would get a rest. Okay, I admit it, I took a 3 hour nap this afternoon. It was wonderful! I also have begun the task of preparing for the end of this year's field season. That is, I made a list of people I need to write thank you letters to and began drafting them. I also finished tape 9 with respect to video logging the dolphin identities that can be made.

Another boat trip on calmer seas.

At least 75 individual dolphins observed today! Today I recorded about 40 minutes of video and identified at least 30 individual dolphins prior to reviewing the video. We saw a group of sub-adult males socializing and milling about near Subarune. One or two of these males later joined the group we'd been watching near Kawaguchi Taki on the South side of Mikura Island.

We had our longest underwater observations today on Mikura's south 'side' in front of Kawaguchi Taki.

A thunderstorm began the morning …

… but did not dissipate the heat or the following sun. I had been watching the white caps increase from my door up the hill from the ocean. The swells did not become apparent till I got down to the port. We could only go from the new pier around the east to Motone. At both the pier and Motone, there was a 1~2 m swell. The wind was 20~25 kn but gusted to ~30 kn.

A quick start for an early morning boat trip

Ichiro-sensei had his boat out today for some teachers, and me. While we did not see the new calf born yesterday, we did see many other dolphins today: about 50-60 in total as different IDs. We had 6 sightings but swam with only 3 of the groups. Two were fleeting with only one surface observation of a couple of dorsal fins. The other was a group of resting dolphins that moved off when passengers from a second boat near us entered.