In brief, the US attempted to restrict imports of yellow fin tuna caught by Mexican fishing boats because too many dolphins were being killed in the process. (clivehamilton.com)
According to Defenders of Wildlife, fishermen started to notice a half century ago that schools of yellow fin tuna seemed to follow dolphins that swim higher in the water column, especially in the Eastern Tropical Pacific. (scientificamerican.com)
Visibility was amazing reaching 30 m / 90 ft.. We saw: black tip sharks, grey reef sharks, huge school of big eye trevally, school of giant sweet lips fish, bumphead parrotfish, school of yellow fin barracudas, couple of dog tooth tunas, school of spade fish, and thousands of surgeon fish and fusiliers. (aggressor.com)