Recovery of sea otter populations yields more benefits than costs
New model puts dollar value on ecological transformations driven by
otters

Date:
June 11, 2020
Source:
University of British Columbia
Summary:
Researchers have created a new model to evaluate the long-term
economic benefits of top predator recovery, using sea otter recovery
along the west coast of Canada as a case study.



FULL STORY ========================================================================== Since their reintroduction to the Pacific coast in the 1970s, the sea
otters' rapid recovery and voracious appetite for tasty shellfish such
as urchins, clams and crabs has brought them into conflict with coastal communities and fishers, who rely on the same valuable fisheries for
food and income.


==========================================================================
But the long-term benefits of sea otter recovery -- such as healthier
kelp forests, higher fish catches, carbon storage and tourism -- could be
worth as much as $53 million per year, according to new UBC research. If well-managed, these economic benefits could offset commercial losses to shellfish fisheries of $7 million per year.

The study, published today in Science, is the first regional economic
analysis of the costs and benefits of sea otter recovery along the west
coast of Vancouver Island. Critically, it offers a new modeling framework
to evaluate the significant long-term ecological changes driven by a
top predator like the sea otter.

"Our work offers a glimpse into a future where otter populations have
recovered to an estimated 5000 animals, and have fully reoccupied their historic range," said lead author Edward Gregr, an adjunct professor at
the Institute for Resources, Environment and Sustainability at UBC. "We
found that coastal ecosystems with otters present are almost 40 per
cent more productive. In the long run, that equates to higher fish
catches worth $9 million, carbon storage worth $2 million and tourism opportunities worth $42 million per year." That's because the hungry
otters drive huge transformations to their local ecosystems: by keeping
urchin populations in check, they allow kelp forests to recover. Healthy
kelp forests, in turn, sequester carbon and support abundant marine life,
from salmon and lingcod to seals and whales.

For the analysis, researchers integrated local ecological field studies
with available economic data and a recent tourism study, and accounted
for uncertainties in future values and potential interactions among the
species in the coastal ecosystem.

"It's clear that humanity must reverse the decline in biodiversity
if we want to achieve a sustainable future," said co-author Kai Chan,
a professor at IRES and the Institute for the Oceans and Fisheries at
UBC. "This study demonstrates that restoring key species to ecosystems
can also have great benefits for people, and could serve as a useful
framework for evaluating top predator recovery elsewhere." But,
the researchers warn, the costs and benefits of such large ecosystem reorganizations are often not equally distributed. In British Columbia,
future management decisions must consider the implications for local
Indigenous communities and fishers, who are experiencing the losses from shellfish fisheries more acutely.

For example, while commercial fishers are likely to adapt to fewer crabs
in shallow waters by fishing in deeper waters, Indigenous or recreational harvesters with more restricted access may not be able to.

"Other costs and benefits -- like food security, culture and tradition
-- are also considerable, but they are more difficult to value in
dollars," said Gregr. "Going forward, we want to scale the model down
and incorporate such impacts at the local level." The researchers hope
that quantifying the impacts of ecological transformations more broadly
will help mitigate conflicts, promote public acceptance of ecosystem
change and help identify opportunities for local communities.

"Sea otters co-existed with and were managed by the Indigenous Peoples
of this region for millennia before they were hunted to near extinction
by the maritime fur trade," said Gregr. "Their recovery is a golden
opportunity for the Government of Canada to reconcile coastal fisheries management with local communities and regional stakeholders to ensure
strong, healthy coastal communities and thriving otter populations."

========================================================================== Story Source: Materials provided by University_of_British_Columbia. Note: Content may be edited for style and length.


========================================================================== Journal Reference:
1. Edward J. Gregr et al. Cascading social-ecological costs and
benefits
triggered by a recovering keystone predator. Science, 2020 DOI:
10.1126/ science.aay5342 ==========================================================================

Link to news story: https://www.sciencedaily.com/releases/2020/06/200611152531.htm

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