Kiva L. Oken, Ph.D.

Quantitative Ecologist and Fishery Scientist

Predation in marine ecosystems

lingcod-trap

Proposed lingcod traps (The Nature Conservancy)

Most of my dissertation focused on predation in marine ecosystems, at both the population and guild scales. I conducted a large simulation studying illustrating our limited power to detect large predation effects on the productivity of prey populations when predation impacts a specific life stage of the prey, and population dynamics are stochastic and observed imperfectly. I examined the structure and dynamics of marine predator assemblages, developing an index of predation to study assemblages as they are perceived by particular prey species. Despite the complex nature of marine ecosystems, these predator assemblages were frequently dominated by one or two individual predators. I also showed that there is little evidence of synchrony or asynchrony within these predator assemblages, which could either magnify or stabilize their temporal variability. Finally, collaborating with Jodie Toft at The Nature Conservancy Washington, I used a case study to exemplify the value of considering predation in fisheries management. In the California Current, lingcod are both apex predators and a valuable fishery, but their yield is limited by shared habitat with sensitive rockfish populations. However, it is possible for decreased predation on rockfish by culled lingcod populations to offset the increased yield of rockfish as bycatch in a lingcod fishery. The viability of this possibility depends strongly on how much rockfish lingcod are consuming.

In general, I think that predation is an important process in marine ecosystems that sometimes matters for fishery management, but it is also complex, and failing to account for that complexity can misinform conclusions.

Publications:
Oken K.L., T.E. Essington, and C. Fu. (2018) Variability and stability in predation landscapes: a cross ecosystem comparison on the potential for predator control in temperate marine ecosystems. Fish and Fisheries. 19:489-501. (link)

Oken K.L. and T.E. Essington. (2016) Evaluating the effect of a selective piscivore fishery on rockfish recovery within marine protected areas. ICES Journal of Marine Science. 73:2267-2277. (link) (press release)

Oken K.L. and T.E. Essington. (2015) How detectable is predation in stage-structured populations? Insights from a simulation-testing analysis. Journal of Animal Ecology. 84:60-70. (link)

Presentations:
ICES Annual Science Conference, Ft. Lauderdale, FL, 2017

Western Groundfish Conference, Newport, OR, 2016

American Fisheries Society Annual Meeting, Portland, OR, 2015

Ecological Society of America Annual Meeting, Sacramento, CA, 2014

PICES Annual Meeting, Nanaimo, B.C., 2013