Two former government scientists say their superiors shot down years’ worth of research on the effects of tuna fishing on dolphin populations because the findings clashed with the policy aims of the Clinton and Bush administrations. Separate research conducted by Albert Myrick and Sarka Southern indicated that dolphins are exposed to dangerous levels of stress by the practice of chasing and encircling them to catch tuna. Myrick says he retired from his government post in 1995 after he was not permitted to continue his work, and Southern says she was forced to abandon her dolphin study and focus on other projects. The accusations come just after the Bush administration relaxed the rules for labeling “dolphin-safe” tuna to include the fishing practice, which Commerce Secretary Donald Evans said had “no significant adverse impact” on dolphins. The Commerce Department denied that it had suppressed research and blamed the termination of the scientists’ work on lack of financing and problems with peer review. But Sen. Barbara Boxer (D-Calif.) said she would call for hearings to determine whether the Bush administration was playing fast and loose with scientific findings.