FW364 Ecological Problem Solving

1. FW364 Ecological Problem Solving Lab 7: Loggerhead turtle conservation

2. Log onto computers please Download files from saraparrsyswerda.weebly.com/fw364-ecological-problem-solving.html

3. Outline for Today • Lab 7: Investigate loggerhead turtle conservation strategies • Determine baseline population growth • Comparison of turtle conservation strategies

4. Loggerhead Turtle Background A little big about loggerhead turtles… World’s largest hard-shelled turtle: average size ~35” and 300 lbs Long-lived (47-67 yrs) with delayed sexual maturity (17-33 yrs) Broadly distributed: Found in Atlantic, Pacific, and Indian oceans Endangered species Causes of decline: Mortality: Over-harvest (intentional harvest) By-catch by commercial fisheries Eating trash Reduced fecundity: Loss of nesting habitat Introduction of exotic nest predators e.g. Red fox in Australia  Subject of intense conservation efforts

5. Loggerhead Turtle Background Undergo large migrations Tracks for nine leatherback turtles North America Europe Illustrate wide movement patterns of sea turtles Africa South America

6. Turtle Conservation To reduce turtle by-catch in shrimp fisheries, fishermen are required to include turtle excluder devices (TEDs) in their nets TEDs are the primary management tool for reducing adult mortality

7. Turtle Conservation lost habitat existing habitat Dramatic sea turtle nesting habitat loss green turtle Conservation efforts: Protecting nesting beaches Protecting nests Transplanting eggs to hatcheries hawksbill turtle

8. Loggerhead Turtle Stages Five stages: (0) Hatchlings Small juveniles Large juveniles Subadults (i.e., small adults) Adults Loggerhead Leslie matrix (from textbook): 11S 22S 33S 44S 01S 12S 23S 34S Small Juveniles Large Juveniles Hatchlings Adults Subadults 3F 4F

9. Lab 7 – Loggerhead Turtle Conservation Goal: Use a stage model to evaluate two alternative conservation strategies: Increasing adult survival vs. adult fecundity • Two parts: • Determine baseline population growth • Comparison of turtle conservation strategies

10. Lab 7 – Loggerhead Turtle Conservation • Part A: Determine baseline population growth for loggerhead turtles • Run a stage-structured simulation (see lab manual for parameters) and determine: • Final population size (total number of turtles)

11. Lab 7 – Loggerhead Turtle Conservation • Part B: Comparison of turtle conservation strategies • Compare cost-effectiveness of two management strategies: • Use of TEDs to increase survival rates of subadult and adult turtles • Protection of nesting beaches and transplanting eggs to hatcheries to increase subadult and adult fecundities • Givens: • Increasing the three subadult and adult survival rates (33S, 34S, 44S) by 1% costs the fishermen $10,000 • Increasing both subadult and adult fecundity rates (3F, 4F) by 1% costs taxpayers $2,500

12. Lab 7 – Loggerhead Turtle Conservation Assumptions: Assumption about demographic stochasticity Assumption about density dependence Assumptions motivating your recommendations to policy makers (e.g., assumptions about human behavior, who should pay for conservation efforts, right to impose conservation costs on particular groups vs. sharing costs)