Summary of Orca Research in 3 Easy Steps.
Step One. There are noisy and quiet years in the Salish Sea because of economic booms and busts. Everyone knows the oceans got quieter when shipping activity fell during part of the pandemic, but did you know it also fell at least five other times since the late 1970s?
See the figure here for our noise disturbance measure and its link to economic activity. Notice that these changes are large, and there are several of them.
Step Two. Comparing fertility and mortality in noisy years vs quiet years, we find KW mortality in noisy years is significantly higher, and KW fertility, in the year after a noisy year, leads to fewer births. This timing is exactly what you should expect if a noisy year lowers conception.
See the figure here for the probability of a SRKW dying at various ages in an average noise year vs a very noisy year.
See the figure here for the probability of a female SRKW giving birth at various ages, one year after, an average noise year vs one year after a very noisy year.
Step Three. If vessel noise is really creating these impacts, then surely the Northern Resident Killer Whales (NRKW) who are infrequently in the Salish Sea should be affected less than the completely exposed Southern Residents?
See the figures here for a comparison of births and deaths, for noisy vs quiet years, for the NRKW. Notice that there is very little if any difference across these years for the NRKW, but there are large and significant differences for the SRKW as shown in Step Two above.
Presidential Address at the 2021 Canadian Economics Association Meetings: The Orca Conjecture
M. Scott Taylor
In this Address I argue that the Southern Resident Killer Whale (SRKW) population has been negatively affected by booming commercial vessel traffic, tied to international trade, in the post 1998 period. I present new data showing a dramatic increase in the volume of km travelled and the composition of vessel traffic in the Salish Sea. By exploiting recent work in biology linking vessel noise to changes in foraging and socializing behavior, I conclude the negative shock has degraded their habitat significantly. Surprisingly, the competing population of Northern Resident Killer Whales (NRKW) may be an unwitting benefactor of this negative shock; and as a result the SRKW are now on a slow-motion path towards extinction.
Important related work:
Bigg, M. A. (1982) “An assessment of killer whale (Orcinus orca) stocks off Vancouver Island, British Columbia.” Report of the International Whaling Commission 32, 655-666.
Colby, J. M. (2018) Orca: How we came to Know and Love the Ocean’s Greatest Predator, Oxford University Press, UK.
Ford, J. K. B. (2006) An assessment of critical habitats of resident killer whales in waters off the Pacific coast of Canada, Fisheries and Oceans Canada, Science.
McWhinnie, L. H., P. D. O’Hara, C. Hilliard, N. Le Baron, L. Smallsahw, R. Pelot and R. Canessa (2021) “Assessing vessel traffic in the Salish Sea using satellite AIS: An important contribution to planning, management and conversation in southern resident killer whale critical habitat,” Ocean and Coastal Management 200, 105479.
Olesiuk, P. F., M. A. Bigg, and G. M. Ellis (1990) “Life history and population dynamics of Resident killer whales (Orcinus orca) in the coastal waters of British Columbia and Washington State,” Report of the International Whaling Commission 12, 209–243.
Ward, E. J., E. E. Holmes, and K. C. Balcomb (2009) “Quantifying the effects of prey abundance on killer whale reproduction,” Journal of Applied Ecology 46(3), 632–640.
Orcinus Orca is the world's largest predator, and simultaneously a significant tourist asset and cultural icon for much of the Pacific Northwest. In the past two decades, the Southern Resident Killer whales (SRKW) have declined by more than 25 percent, and this population appears on a slow-motion path towards extinction. This paper combines elements from biology and economics to put forward a new methodology for investigating their collapse and presents empirical work supporting its novel explanation - the Orca Conjecture. The key mechanism is ecological - Gause's law of competitive exclusion - combined with a shock coming from booming trade with Asia. Using three different empirical methods drawn from economics, I find the attendant noise disturbance from increased ship traffic post-1998 has lowered births and raised deaths significantly, placing the SRKW on a slow-motion path towards extinction.
Important related work:
Ayres, Katherine L., Rebecca K. Booth, Jennifer A. Hempelmann, Kari L. Koski, Candice K. Emmons, Robin W. Baird, Kelley Balcomb-Bartok, M. Bradley Hanson, Michael J. Ford, and Samuel K. Wasser. 2012. “Distinguishing the impacts of inadequate prey and vessel traffic on an endangered killer whale (Orcinus orca) population.” PLoS One, 7(6).
Copeland, Brian R., Joseph S. Shapiro, and M. Scott Taylor. 2021. “Globalization and the Environment.” In Handbook of International Economics. Vol. V, , ed. Gita Gopinath, Elhanan Helpman and Kenneth Rogoff, forthcoming.
Hoyt, Erich. 2019. Orca: The Whale called Killer. Firefly Books, Ontario, Canada.
Levinson, Mark. 2016. The Box: How the Shipping Container made the World Smaller and the World Economy bigger. Princeton University Press, Princeton, USA.
Smith, Vernon L. 1975. “The Primitive Hunter Culture, Pleistocene Extinction, and the Rise of Agriculture .” Journal of Political Economy, 83(4): 727–755.