Dispatch from the Sea of Japan: Hamachi days

The Conservation & Science team at the Monterey Bay Aquarium has worked for more than two decades to understand and recover bluefin tuna – particularly Pacific bluefin, whose population has declined historically due to overfishing. A key piece of our efforts is tagging bluefin in the wild so we can document their migrations across ocean basins. Much of our work takes place in the Eastern Pacific, but this summer we’re partnering with Japanese colleagues to tag bluefin tuna in the Sea of Japan. Tuna Research and Conservation Center Research Technician Ethan Estess, working with Program Manager Chuck Farwell, is chronicling his experience in the field. This is the third dispatch in his series; you can read the second here.

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Even when the nets come up tunaless, Sado Island offers some lovely sights.

It’s Day 9 of our bluefin tuna tagging expedition in the Sea of Japan. I’m sorry to report that after an exciting first day, we haven’t seen a single tuna in over a week.

We head out at 4 a.m. every day, excited at the prospect of a trap full of big bluefin ready to be fitted with satellite tracking tags. But when our crew hauls the net, what do we find? Lots and lots of yellowtail, or hamachi.

That’s fishing, I guess. Last fall I spent three weeks in chilly Nova Scotia and only tagged two tuna. (Weeks of bad weather kept us stuck in a cabin, watching B-rated movies.) Another year, we were hoping to tag bluefin off of Mexico, but the fishing was so slow we watched the entire Lord of the Rings trilogy in a day.

I’m really hoping this isn’t going to be another one of those trips.

Dispatch from the Sea of Japan: Tuna tagging 101

The Conservation & Science team at the Monterey Bay Aquarium has worked for more than two decades to understand and recover bluefin tuna – particularly Pacific bluefin, whose population has declined historically due to overfishing. A key piece of our efforts is tagging bluefin in the wild so we can document their migrations across ocean basins. Much of our work takes place in the Eastern Pacific, but this summer we’re partnering with Japanese colleagues to tag bluefin tuna in the Sea of Japan. Tuna Research and Conservation Center Research Technician Ethan Estess, working with Program Manager Chuck Farwell, is chronicling his experience in the field. This the second dispatch in his series; you can read the first here.

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A Pacific bluefin tuna swims in the Sea of Japan.

Before we go further into our bluefin tagging expedition in Japan, I want to share a bit of background on this fascinating and politically-charged fish we study: Thunnus orientalis, the Pacific bluefin tuna.

You may have read that bluefin are in decline due to overfishing. The challenge is to sort the headlines from the science. Scientists don’t always have perfect answers, but they do use the best data available to make educated guesses.

Dispatch from the Sea of Japan: Tagging takes teamwork

The Conservation & Science team at the Monterey Bay Aquarium has worked for more than two decades to understand and recover bluefin tuna populations – particularly Pacific bluefin tuna, whose population has declined historically due to overfishing. A key piece of our efforts is tagging bluefin tuna in the wild so we can document their migrations across ocean basins. Much of our work takes place in the Eastern Pacific, but this month we’re partnering with Japanese colleagues to tag bluefin tuna in the Sea of Japan. Tuna Research and Conservation Center Research Technician Ethan Estess, working with Program Manager Chuck Farwell, is chronicling his experience in the field. This the first dispatch in his series.

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Tags are laid out on a tatami mat, prepped and ready for use when the tagging team heads out to sea.

The alarm buzzes beside my head and, opening my eyes, I have no idea where I am.

I’m lying on the floor of a room covered wall-to-wall in woven straw mats, with rice paper windows and a table rising a foot off the ground. Right. Japan. Sado Island in the Sea of Japan, where I’m sleeping on a traditional tatami mat. Yesterday’s cannery whistle is blowing back home at the Monterey Bay Aquarium at noon, but my 4 a.m. alarm tells me it’s time to get up and find some Pacific bluefin tuna.

One year ago, I sat in a third-floor office at the aquarium with my colleague Chuck Farwell and Dr. Ko Fujioka from Japan’s National Research Institute of Far Seas Fisheries as we went through the steps necessary to deploy a satellite tag on a bluefin tuna. We discussed the tag attachment system that anchors the small electronic device to the animal for up to a year at a time, as well as the process for programming the tag’s onboard computer to record the whereabouts and behaviors of these wide-ranging fish.