Population Viability Analysis: Loggerhead Turtles Brook Milligan - PowerPoint PPT Presentation

References Population Viability Analysis: Loggerhead Turtles Brook Milligan Department of Biology New Mexico State University Las Cruces, New Mexico 88003 brook@nmsu.edu Fall 2009 Brook Milligan Population Viability Analysis: Loggerhead Turtles

References PVA Example: Caretta caretta Declining loggerhead turtle ( Caretta caretta ) populations Major mortality of eggs and hatchlings Extensive effort managing nesting beaches Is this the right management strategy? Are there other management actions that would be better? Brook Milligan Population Viability Analysis: Loggerhead Turtles

References Nesting Females: Loggerhead Turtles Brook Milligan Population Viability Analysis: Loggerhead Turtles

References Projected Growth Rates: Loggerhead Turtles (2009) Brook Milligan Population Viability Analysis: Loggerhead Turtles

References Loggerhead Turtle Demographic Data Brook Milligan Population Viability Analysis: Loggerhead Turtles

References Loggerhead Turtle Stage Projection Matrix Brook Milligan Population Viability Analysis: Loggerhead Turtles

References Loggerhead Turtle Stable Stage Distribution Brook Milligan Population Viability Analysis: Loggerhead Turtles

References Loggerhead Turtle Elasticity Analysis Brook Milligan Population Viability Analysis: Loggerhead Turtles

References Loggerhead Turtle Elasticity Analysis Brook Milligan Population Viability Analysis: Loggerhead Turtles

References Loggerhead Turtle Escaping via TED Brook Milligan Population Viability Analysis: Loggerhead Turtles

References Loggerhead Turtle Escaping via TED Brook Milligan Population Viability Analysis: Loggerhead Turtles

References Implementation of Turtle Exclusion Devices (TEDs) 1978: all marine turtles in southeastern U.S. listed as endangered 1978–1980: initial development to TEDs 1981: voluntary program for shrimp fishers 1980–1984: improvements in TED technology 1985–1986: increased efforts to engage voluntary deployment of TEDs 1986: threat to sue by environmental organizations over enforcement of Endangered Species Act 1989: mandatory use of TEDs for U.S. fishers 1989: Public Law 101-162, Section 609 Requires the U.S. to embargo shrimp harvested with commercial fishing technology that may adversely affect sea turtles Currently ≈ 40 countries have certified programs Brook Milligan Population Viability Analysis: Loggerhead Turtles

References Shrimp Seizure: 2004 May 21 10,000 pounds of shrimp seized for lack of federally required marine conservation equipment. Brook Milligan Population Viability Analysis: Loggerhead Turtles

References Shrimp Seizure: 2006 January 13 6,330 pounds of shrimp seized because two of four Turtle Exclusion Devices and one By-catch Reduction Device were sewn shut. Brook Milligan Population Viability Analysis: Loggerhead Turtles

References Shrimp Seizure: 2006 January 13 6,330 pounds of shrimp seized because two of four Turtle Exclusion Devices and one By-catch Reduction Device were sewn shut. Brook Milligan Population Viability Analysis: Loggerhead Turtles

References Historical Shrimp Prices Brook Milligan Population Viability Analysis: Loggerhead Turtles

References Historical Shrimp Prices Value of seized catches: $3.00–$5.00 per pound landed = ⇒ $20,000–$50,000 Brook Milligan Population Viability Analysis: Loggerhead Turtles

References Conant, T. A., P. H. Dutton, T. Eguchi, S. P. Epperly, C. C. Fahy, M. H. Godfrey, S. L. MacPherson, E. E. Possardt, B. A. Schroeder, J. A. Seminoff, M. L. Snover, C. M. Upite, and B. E. Witherington. August 2009. Loggerhead sea turtle ( Caretta caretta ) 2009 status review under the U.S. Endangered Species Act. Technical report, Loggerhead Biological Review Team, National Marine Fisheries Service. Crouse, D. T., L. B. Crowder, and H. Caswell. 1987. A stage-based population model for loggerhead sea turtles and implications for conservation. Ecology , 68:1412–1423. Crowder, L., D. T. Crouse, S. S. Heppell, and T. H. Martin. 1994. Predicting the impact of turtle excluder devices on loggerhead sea turtle populations. Ecological Applications , 4:437–445. Brook Milligan Population Viability Analysis: Loggerhead Turtles