We'd learn that the sea bed is very rocky and I later read that we were far enough south for coral. It made for tricky fishing, at times. I'm sure the seabed is quite littered with old line and lures. Also, I note that the focus is a bit off with this pic - It might be camera shake from the boat's vibration, but I suspect that it's because I was still learning how to actually focus on infinity with a new lens that is oddly marked.
On the way back, I discovered that my hands had burned wherever the skin was exposed. Multiple applications of SPF30 aren't enough when you're fishing for hours under 32°C weather and clear skies! I had worn a wide-rimmed hat and dressed in long pants and wore both a shirt and a pair of stocking-like things for my fore-arms that I'd borrowed from my mother-in-law, and frankly felt a bit silly but seeing the results I'm very glad I took the effort. In Hosoda-san's blog it's apparent that many other clients felt the same way, going to some length to hide from the sun; others, however, wore t-shirts!
Hosoda-san, who runs the charter, maintains a blog, and for those who can read Japanese the link is here. I've stolen some of his photos: