Sturgeon Success Story - Population Recovery in the Suwannee River Gulf Sturgeon Population

Thursday, August 21, 2014: 2:50 PM
206A (Centre des congrès de Québec // Québec City Convention Centre)
Kenneth Sulak , U.S. Geological Survey, Gainesville, FL
Michael Randall , U.S. Geological Survey, Gainesville, FL
Melissa Price , U.S. Geological Survey, Gainesville, FL

There are few sturgeon recovery success stories from Eurasia, but the situation is more promising in North American.  A particularly encouraging success story is that of the Suwannee River Gulf sturgeon.   In the 30 year period since the 1984 Florida harvest ban, the Suwannee population has rebounded vigorously.  Reduced by overfishing to about 2,000 individuals, the population has increased to about 7,500.  Adults have increased from 10% (1995) to over 50% (2009-2013).  Length frequency data from 25 years of mark-recapture shows a 2013 population with an overall normal distribution, comprised of at least ten solid year-classes. Good juvenile recruitment has occurred nearly every year in the past 15 years (versus every 5-7 years in the early 1990s).  Recruitment gaps are evident only during serious drought years (1999, 2000, 2002).  Annual natural mortality has remained stable at 11-12% from 2000-2013 (versus 16-17% in the early 1990s).  The population appears to be approaching natural carrying capacity, with signs of increased outmigration and expansion into peripheral habitats in the upper river.  The post-protection story of the Suwannee River Gulf sturgeon population demonstrates the capacity for fairly rapid and vigorous natural recovery in sturgeons, without supplementation, when the habitat quality remains suitable.