The head of Kentucky's Department of Fish and Wildlife Resources has resigned the position he has held since 2005.The chairman of the department's commission says Jonathan W. Gassett submitted a letter of resignation Thursday evening.Commission chairman Stuart Ray says Gassett is resigning to pursue outside interests.Gassett's department had come under heightened scrutiny in recent years over concerns about spending and personnel decisions. The Office of Inspector General in the Kentucky Cabinet for Public Protection is conducting an investigation, and a legislative committee concluded its own review last month.Gassett, a biologist with a Ph.D., came to the agency in 1999 and oversaw the state's program to reintroduce elk to eastern Kentucky.Ray says deputy commissioner Benjy Kinman would become the interim head of the agency.