Past

1. Past Present Future Norbert Wu photos

2. How many whales before whaling?

3. Co-author Joe Roman at Harvard U.

4. IWC Revised Management Procedure “...catches should not be allowed on stocks below 54% of the estimated carrying capacity.”

5. IWC pre-whaling estimates for the north Atlantic Humpback 10 - 20,000 Fin 30 - 50,000 Minke 100,000 ? Total 140 - 170,000 Based on reported catch in 19th and 20th centuries

6. For the North Atlantic: Original Now Humpback 10 - 20,000 12-15,000 Fin 30 - 50,000 56,000 Minke 100,000 ? >150,000 Total 140 - 170,000 ca.220,000 Based on modern censuses by the IWC

7. Genetic estimates of population size Inbreeding decreases genetic diversity Mutation increases genetic diversity

8. Genetic estimates of population size Small populations have strong inbreeding Low diversity

9. Genetic estimates of population size Large populations have low inbreeding High diversity

10. For stable populations and neutral mtDNA variation: = 2Ne(f) : genetic diversity : substitutions/generation

11. Mutation rate Rate = 1.5 - 2.0% per MY Silent divergence at cyt b Divergence in d-loop

12. Generation time 1) Based on whaler records of average age of mature females 2) Based on annual survival from photo-identified females 12 - 24 years

13. High global mtDNA diversity for humpback whales Genetic diversity predicted for 115,000 whales 4% 3% 2% 1% 0 Branch lengths (percent substitution)

14. Genetic estimates of world-wide population >1 million humpbacks Genetic diversity predicted for 115,000 whales Data from Palsbol, Baker, Palumbi 4% 3% 2% 1% 0 Branch lengths (percent substitution)

15. Gene trees also contain information about the growth or crash of populations Tips pruned away = crash Too few deep branches = growth 4% 3% 2% 1% 0 Branch lengths (percent substitution)

16. 340 humpback mtDNA sequences from six populations 188 from North Atlantic in red

17. North Atlantic humpback mtDNA diversity = 2.2% (n = 188) ==> female size = 68,000 ==> population size = 240,000 ± 60,000 ca. 15% global total

18. Current view of the history of humpback whales Original population - 115,000 N. Atlantic original - 10-20,000 N. Atl current - 13,000 MSY N. Atl - 6,000 - 11,000 Ready for harvest

19. Genetic view of the history of humpback whales Original population - 1,500,000 N. Atlantic orginal - 240,000 N. Atl current - 13,000 MSY N. Atl - 170,000 Ready for harvest in 50 years

20. North Atlantic Fin whales mtDNA diversity = 4.3% (n = 224) ==> female population 102,000 ==> total population = 360,000 ± 90,000

21. Potential limitations - Accuracy of mutation rate sets accuracy of estimates Generates long term, ‘typical’ population size Tends to dramatically underestimate populations Chance events may distort single gene estimates

22. Sensitivity analysis: Estimates of 20,000 whales require extreme parameter values Generation Time (Yr) 20 15 Mutation rate

23. Why the discrepancy? How are whaling records used to chart history? “Inconceivable”: Phil Clapham

24. Fin whale historic numbers 30-50,000 Sergeant 1977 widely cited, perhaps “greater than 30,000 and probably less than 50,000”

25. Fin whale historic numbers Honest guess ------> sacred text

26. Humpback history Total recorded catch = 29,279 Humpback whale catch Year Data from Tim Smith and Randy Reeves. Fig from Stevick et al. 2003

27. Current assumption sets: Assume 98% of whales harpooned after 1870 are landed Assume 100% of whales killed in the ocean are recorded Assume total population = number killed during whaling heyday Assume zero aboriginal catch

28. Alternatively: Assume 50% of whales harpooned are landed (data from Mitchell and Reeves 1983, Table 10) Assume 50% of whales killed are recorded in current summaries

29. 3600 Total mortality from hunt: ca100,000 2800 Historic population size: ca 80,000 2000 Humpback whale mortality 1200 400 Year

30. More sophisticated models incorporating whale log data are currently a ‘poor fit’ to modern data (IWC 2003, p. 295) “it is possible that removals from earlier periods [19th century] have been significantly underestimated.” (IWC 2003, p. 295)

31. Perry et al. 1999 - dropped estimates of original pop sizes from US report on whale status “Not estimatable” Past Present Whaling rates might be calculated strictly on the basis of current population growth Future

32. Why are humpback populations growing so fast? Perhaps they are far from their upper population size -?

33. What history-less management tells us about future whaling Humpbacks harvest Fin whales harvest Gray Whales harvest Minke whales harvest Blue whales not yet

34. What genetic history tells us about future whaling Humpbacks not yet Fin whales not yet Gray Whales ? Minke whales ? Blue whales not yet

35. Genetics adds independent data and a different assumption set Past is visualized using historical data and a series of assumptions

36. DNA views of turtle history? Loggerhead and green turtle effective population size is small - 10,000

37. DNA views of turtle history? But each Loggerhead carries parasitic barnacles - and their populations were huge - >10 million

38. Ocean ecosystems were probably dominated by the great whales before we ate them.