We've been working on
a sea otter project looking at the conflict between commercial fisheries
and sea otters.
In southern Southeast Alaska we're seeing increases
in the sea otter population. They're actually fairly significant increases, so this is
a growing
population both in distribution and abundance.
The issue was brewing in my mind for a couple years before
Zac approached me about trying to tackle it from a research end.
Primarily that was because
Dungeness crabbers were coming and either talking to me or I'd listen to them
testifying at Shellfish Board of Fish meeting.
Their concerns are both for
their bottom line but I think also for the resource because
once they've seen otters in a bay for several years or even just one or two
years,
they won't fish there anymore because they're not catching any
crab there anymore. They're worried that they're going to lose their income.
They're also worried that that because they're being forced into the
smaller areas they're going to overly deplete
that resource. Right now sea otters are competing directly for the
California sea cucumbers,
which are commercially harvested by divers, as well as geoduck clams, red
sea urchins
and the Dungeness crab fishery. Sea otters were
extirpated on by the commercial fur trade probably by
the late 1800s and by 1911 when
the International Fur Seal treaty was put in place,
sea otters were non-existent southeast Alaska. Otters were reintroduced in the
late sixties.
A little over 400 otters were translocated. The populations
were really insignificant as a related to competition with commercial
fisheries for probably
twenty-plus years. But as these populations of otters got established
they got to a point where they could
grow rapidly in the in the way of numbers.
At the same time, commercial fisheries were being developed. We really
started seeing the conflict between
otters and fishermen probably in the early nineties. At that point the
otter population was at a level that it was impacting
commercial fisheries. Since that time we've seen
the otter population continue to grow as well
as the participation and value of some these commercial fisheries grow.
We've seen several areas that have been closed to commercial fishing.
And once those areas have been depleted of a couple of these resources, they've
they've remained closed.
Sea otters are kind of at the top of their food chain.
And they're voracious predators. Because of that voracious appetite
they have the ability to consume a lot
in an area. So the classic paradigm is that where otters move in
they remove herbivores from the ecosystem and that allows
kelps to reestablish themselves. And some these large canopy
kelps such as macrocystis, those are important and very productive habitats
especially for early life history.
We're seeing in areas where otters are moving in, they're changing
those ecosystems currently here.
Areas that are going from a monoculture, like
urchin barrens for instance, changing into a
more diverse ecosystem. And that's great when we talk about
ecosystems, but when we talk about commercial fisheries that's not a good
thing.
That is precluding some of the existing fisheries
from moving forward in southeast Alaska.
These populations of otters, they haven't been followed well since they were
reestablished.
So the first thing we need to do is just know how many otters were here.
And once we establish that, ongoing with
those efforts to survey the otters, we also felt it was very important to look
at the
diet of sea otters. What are sea otters consuming? What proportion of their diet
is these commercially important species? We're using high-powered telescopes
to observe otters. Lucky for us, otters bring everything they eat to the surface.
We're also recording their dive times, and how many calories per unit effort an
otter is consuming.
Commercially important species are some other most calorically rich and preferred prey of
sea otters. The third aspect of this research
is to look at otters' movement at the edge the range.
We've established that otters are impacting these commercial fisheries.
And so one of the things we wanted to do is look at otters and
how otters were distributed and how their dispersal was from these
edge of the range areas. As otters move into new areas, areas there haven't
been
existing are established populations in yet,
we were questions what's going happen here in the next year or two. So we've
instrumented
30 otters in this area with VHF transmitters
and we're following those otters as they disperse from where we caught them.
The next step of the research is collecting forging data from those
animals.
Right now we're working in Saginaw Bay. This bay has been inhabited by sea otters
probably for about seven or eight years now.
and there's no longer a commercial dungeness in Saginaw bay.
Today we probably saw 100 to 125
otters in the bay. It looks like from some work we've done previously they're
mostly eating several species of clams and smaller crabs.
We may be able to make some kind of prediction
for commercial fishermen that says
this is what you can guess is going happen in the next 5 10 15 years
in your fishery as we see this otter population change.
The project itself is not going to be providing
answers or recommendations for what to do,
but we'll be providing information that will help
decision-makers, policymakers, community members and commercial fishermen
make decisions about what to do in response,
if anything.