Todd,
The article may be old but the events are not. I see a connection between the seeming early appearance of the fish and quakes in the area. Perhaps there are mechanisms at work early on in a subduction zone quake that the fish are sensitive to. I am sure that each of the mentioned quakes has some unique characteristics which make this kind of behavior difficult to point to and say, "There will be a quake at a given time and date." It is interesting to look back and spot things that 'might' have been a warning. That is one way to learn that the earth in fact does warn us, we just have to decipher the events correctly.
Ancient tales and legends are not just stories but come from the observations and wisdom of those who were closer to the earth than we are today. Some have good answers but which ones? That is a tough question to answer and is not always 100 percent. I am sure there are going to be many stories in the near future about what may have been early warning signs for Japan's BIG quake,at least for this area.
I am reminded of the story about a paleontologist who wanted to find a giant ammonite at a site known for some several feet in diameter. He spent a day at the site each year for some 16 years, eating his lunch on the same big rock. You guessed it, he looked at the 'rock' one time and it was a giant ammonite.
Sometimes we look and do not see what is right in front of us. Makes life interesting!
Bob in Woodland Hills