I remember being pleasantly surprised when this episode aired. I spent a couple of months living with an ojí-san in Miyazaki in Kyushu, and we went fishing often. I've personally caught and/or eaten all the fish that was shown in that episode.
The weird thing is, even local Japanese will throw out an aigo if they catch them. The oji-san went around and collected them from other fishermen if they caught them. The sashimi was legit the best I've ever tried, it's buttery with a very smooth texture. I'm probably one of the only foreigners who've ever had aigo sashimi lol.