That is terrible. How did that happen? Did he get tangled in something? Was there a current?
A buddy of mine took his 11 year old lab on one last trip to Arkansas this year. On his first retrieve he picked up a nice pintail and on the way back stopped in the middle of the decoys, spit out the duck and started foaming at the mouth. He apparently couldn't move. My friend walked out to him and eventually he came around. Vet thinks his system couldn't handle the excitement/exertion any more and he had a seizure. Anyway if it had happened in swimming water instead of a flooded rice field (or if he had fallen down in the rice field) he could have drowned. That was Jake's last retrieve. Hopefully he will have a nice, long retirement.