The waters around Japan are warmer each day, the sea eels are not coming from Tokyo Bay as they move out to swim and feed. The texture changes and sea eel is softer. Here is a signature of Mr. T – his boiled anago and it is always served as a last bite. On the left is salted and the right is sweetened by tsume: https://mesubim.com/2016/03/30/tsume-explained/

https://mesubim.com/2015/04/03/anagos-deba-video/