Availability of Prey for Southern Resident Killer Whales
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Availability of Prey for
Southern Resident Killer Whales
Technical Workshop Proceedings
November 15-17, 2017
Editors: Andrew W. Trites
David A.S. Rosen
Hosted by:
Marine Mammal Research Unit
Institute for the Oceans and Fisheries
University of British Columbia
Vancouver, BC, CanadaAvailability of Prey for Southern Resident Killer Whales
Technical Workshop Proceedings
November 15–17, 2017
UBC Marine Mammal Research Unit
Editors: Andrew W. Trites
David A.S. Rosen
These workshop proceedings should be cited as:
Trites, AW and Rosen, DAS (eds). 2018. Availability of Prey for
Southern Resident Killer Whales. Technical Workshop Proceedings.
November 15–17, 2017. Marine Mammal Research Unit, Institute for
the Oceans and Fisheries, University of British Columbia, Vancouver,
B.C., 64 pages
The information contained in this document is provided as a public
service. Although we endeavour to ensure that the information is as
accurate as possible, errors do occur. Therefore, we cannot
guarantee the accuracy of the information. It is important to note
that the opinions and suggestions contained in this document do not
necessarily reflect a consensus of every workshop participant, nor
the institutions or organizations they represent.
Cover image credit: Oil painting “Hide and Seek” by Bruce Muir (2017)
Marine Mammal Research Unit
Institute for the Oceans and Fisheries
University of British Columbia
Room 247, AERL, 2202 Main Mall
Vancouver, B.C. Canada V6T 1Z4
Tel.: (604) 822-8181
Email: mmru@oceans.ubc.ca
Web: www.mmru.ubc.ca
Availability of Prey for Southern Resident Killer Whales—Technical Workshop Proceedings 2018 • page 2Table of Contents Executive Summary ...................................................................................................................................... 4 Overview of Workshop ................................................................................................................................ 6 Goals. ........................................................................................................................................................ 6 Terminology.............................................................................................................................................. 6 Assumptions & Limitations. ..................................................................................................................... 6 Participants. .............................................................................................................................................. 6 Proposed Management Actions. ............................................................................................................. 6 Workshop Structure. ................................................................................................................................ 6 Summary of Discussions on Potential Management Actions ..................................................................... 7 A: Increase abundance of Chinook coast-wide by reducing removals by fisheries ............................... 7 B: Increase abundance of Chinook in specific-areas and times by adjusting removals by fisheries ..... 8 C: Increase accessibility of Chinook by decreasing acoustic & physical disturbances ........................ 11 Conclusions ................................................................................................................................................. 13 What Actions to Take ............................................................................................................................. 13 Measuring Efficacy of Actions ................................................................................................................ 13 Future Refinement and Planning ........................................................................................................... 14 Acknowledgements .................................................................................................................................... 14 Appendix A: Participants ............................................................................................................................ 15 Appendix B: Agenda ................................................................................................................................... 17 Appendix C: Participant Presentation Summaries ..................................................................................... 20 Day 1 – Prey Requirements of Southern Resident Killer Whales (SRKW) ............................................... 20 Day 2 – Availability of Chinook Salmon................................................................................................... 31 Day 3 – Evaluation of Potential Mitigation Measures ............................................................................ 38 Appendix D: Management Action Tables ................................................................................................... 40 Appendix E: Table Definitions .................................................................................................................... 49 Appendix F: Notes from Group Discussions—Increase coast-wide Chinook abundance by reducing fisheries ....................................................................................................................................................... 51 Appendix G: Notes from Group Discussions—Increase Chinook abundance at specific times and places55 Appendix H: Notes from Group Discussions—Increase Chinook accessibility at specific times ................ 60 Availability of Prey for Southern Resident Killer Whales—Technical Workshop Proceedings 2018 • page 3
Executive Summary to implement this coast-wide action. The
scientific justification and confidence in this
This workshop assembled scientists and action producing the desired benefits to SRKW
managers with technical expertise on killer were ranked unknown or low.
whales and Chinook salmon to identify and
Action B. A more directed approach that evoked
evaluate short-term management actions that
greater scientific confidence was to limit
might increase the immediate abundance and
fisheries in times and places that correspond to
accessibility of Chinook salmon for southern
SRKW foraging activities. The assumption of this
resident killer whales, given the current size of
action is that limiting fishing where SRKW
Chinook salmon stocks. The workshop did not
normally feed would reduce direct competition
consider ways of producing more Chinook
with them, and increase their foraging success.
salmon (which will be the subject of a
Most of the vessels fishing within SRKW habitat
subsequent workshop), but rather considered
are recreational. While scientific confidence in
ways of making more of the fish that are
this action was greater than for the “blanket”
presently in the ocean available to southern
closures of fisheries throughout BC, there were
resident killer whales (SRKW).
still concerns about its potential effectiveness.
Workshop participants presented and discussed Chief among these were uncertainties about
technical information on the prey requirements how much prey are needed for SRKW to
of SRKW, the availability of Chinook salmon, and successfully forage and meet their needs,
current protections for SRKW. Participants then uncertainty in predicting foraging patterns and
split into four groups with an even distribution of identifying which locations are most important,
expertise to review three potential non- and whether partial or total fishery closures
exclusive Management Actions: within SRKW habitat would significantly increase
A. Increase the abundance of Chinook for the numbers of Chinook that SRKW could
SRKW by reducing coast-wide fishery capture. The scientific justification and
confidence in this action producing the desired
removals.
benefits to SRKW were ranked low to medium.
B. Increase the abundance of Chinook for
SRKW by adjusting fishery removals at Action C. This action was designed to increase
specific times and in specific areas of Chinook accessibility to SRKW by decreasing
SRWK habitat. acoustic and physical disturbance from vessels.
C. Increase the accessibility of Chinook by This action was considered and discussed in the
decreasing underwater noise and the context of all vessels—and not fishing vessels
physical presence of vessels where SRKW alone (which are believed to make up a relatively
forage. small portion of all the vessels encountered by
SRKW). Reducing incidences of disturbance can
Action A. One way to significantly increase the
be achieved by 1) excluding all vessels from
numbers of fish in SRKW habitat—and thereby
important SRKW habitat, and 2) implementing a
increase the foraging success of SRKW—might
200 m exclusion zone around SRKW. Such a
be to prevent fisheries from catching Chinook
protective bubble would limit how close vessels
earlier in their migration before they enter SRKW
could approach SRKW, but would not protect
foraging areas. However, there was considerable
whales if they chose to approach vessels within
uncertainty among workshop participants about
their habitat. The scientific justification and
the underlying theory and the practical capacity
Availability of Prey for Southern Resident Killer Whales—Technical Workshop Proceedings 2018 • page 4confidence in this action producing the desired Chinook can include improvement in body
benefits to SRKW were ranked medium to high. condition of SRKW, increased use of foraging
areas, and less time travelling and feeding (and
Based on the current state of knowledge and
more time resting and socializing). However, use
best available data, workshop participants had
of these metrics requires a commitment to data
higher confidence in the effectiveness of Action
C (limiting vessel disturbances to make the collection and analyses (and forethought into
Chinook that are already present easier for how to interpret them) so that the effectiveness
SRKW to catch) than they did in increasing the of the actions can be assessed and modified as
abundance of Chinook by closing or adjusting necessary.
fisheries (Actions A & B).
This workshop was a first step in bringing
With >900 stocks of Chinook salmon migrating
together scientists and managers with killer
through BC waters at different times and
whale and Chinook salmon expertise from
strengths, there is currently insufficient evidence
to support being able to surgically manage Canada and the United States to identify and
fisheries to avoid catching the stocks destined evaluate short-term management actions that
for SRKW habitat. Nor is there evidence that might be taken to increase the immediate
fishery reductions would add significant abundance and accessibility of Chinook salmon
numbers to the estimated 600,000 Chinook for SRKW, given the current size of Chinook
thought to currently move through inside waters stocks. Going forward will likely require a
to Puget Sound and the Fraser River. smaller group of managers and scientists with
It will be critical to employ well-thought-out expertise in killer whales and Chinook to develop
experimental designs that allow continual detailed strategies, design the experimental
evaluation of the effectiveness of any implementations, and identify the required
Management Action enacted. This is likely to be analyses to ensure that any of the Management
important for the stakeholders and public Actions undertaken are effective in improving
seeking reassurance that SRKW will realize the the status and well-being of southern resident
full benefit of the intended action. killer whales.
Performance measures that can be used to
determine whether SRKW captured more
Availability of Prey for Southern Resident Killer Whales—Technical Workshop Proceedings 2018 • page 5Overview of Workshop actions regarding rebuilding Chinook stocks are
to be addressed in a future workshop. Thus, we
Goals. To identify short-term management only considered short-term actions that could be
actions that might be taken to increase the implemented through existing legislation and
immediate abundance and accessibility of regulations.
Chinook salmon for southern resident killer
whales, given the current size of Chinook stocks. Participants. Participants with technical know-
Thus, we evaluated short-term fishery ledge about killer whales, Chinook salmon, and
management actions that would provide fisheries management were invited from Canada
immediate benefits to southern resident killer and the United States. These included 46
whales (SRKW). We did not consider ways of individuals working for state and federal
producing more Chinook salmon, but rather governments, consulting companies, nonprofit
considered ways of making more of the fish that organizations, and universities (Appendix A).
are in the ocean available to SRKW to ultimately Proposed Management Actions. Given the
increase the birth rates and decrease the death afore-mentioned conditions, five potential (non-
rates of SRKW. exclusive) Management Actions were developed
Terminology. “Availability” means being able to in consultation with Fisheries and Oceans
be used or obtained. This term is used by some Canada (DFO) and US National Marine Fisheries
to mean accessibility, while for others it reflects Service (NMFS) biologists and managers.
the combination of both accessibility and However, workshop participants proposed
abundance. We used this later definition when facilitating discussions by grouping the five
referring to the availability (i.e., availability = potential actions into these three:
abundance + accessibility) of prey for killer A. Increase abundance of Chinook coast-wide
whales. “Accessibility” was defined as the ease by reducing removals by fisheries.
of obtaining or using prey; and "abundance” B. Increase abundance of Chinook in specific-
referred to the quantity or amount of Chinook areas and times by adjusting removals by
salmon in areas where killer whales forage. fisheries.
Assumptions & Limitations. For the purposes of C. Increase accessibility of Chinook by
attaining the goals of the workshop, we assumed decreasing acoustic and physical
that: disturbances.
1. The SRKW population trajectory is in The goal of these three Management Actions
decline and will not improve under current was to increase the short-term abundance or
conditions. accessibility of 4-5+ year old Chinook salmon in
areas where SRKW forage. SRKW consume
2. The status of SRKW is related to the Chinook 3+ years old, but prefer Chinook that are
abundance and accessibility of Chinook 4 years and older.
salmon. Workshop Structure. On Days 1 and 2 of the
Workshop participants did not consider the workshop, experts gave presentations in their
veracity of these assumptions, and focused fields to inform the scientific validity of any of
instead on evaluating management actions that the three potential management actions
could increase the abundance and accessibility (Appendices B and C). Day 3 of the workshop was
of adult Chinook salmon (currently in the ocean) dedicated to working in four groups to
within regions where SRKW forage. Potential independently discuss the possible actions.
Availability of Prey for Southern Resident Killer Whales—Technical Workshop Proceedings 2018 • page 6Discussions were guided by (but not limited to) a would ultimately move “downstream” and enter
series of criteria developed in consultation with areas where SRKW forage. Nor is it clear how
NMFS and DFO prior to the workshop (Appendix many more fish might join those already moving
D). through key foraging areas used by SRKW as a
result of this action.
The overall goal was for workshop participants to
consider how the three actions could be Based on the evidence presented at the
workshop, scientific confidence that this
implemented, and the likelihood that they would
Management Action was feasible or would
increase the abundance and accessibility of
provide the desired benefit to SRKWs was
Chinook for southern resident killer whales to overwhelmingly low or unknown.
consume. While consensus building within
groups was desirable, care was taken to The lack of endorsement for taking this action
document all opinions. was primarily due to:
Concern over being able to obtain real-time
scientific information on the movements of
Summary of Discussions on different salmon stocks to implement
Potential Management Actions selective fishery reductions coast-wide;
Uncertainty concerning whether reducing
The following summaries reflect the discussions catches in “distant” fisheries would increase
held on Day 3 of the workshop concerning each the abundance of Chinook by enough to
of the Management Actions. Notes combining improve SKRW body conditions.
information transcribed during group Mathematical models indicate that such an
discussions, and from tables filled out by action would not significantly increase the
workshop participants are contained in biomass of Chinook salmon for SRKW. This
Appendices F, G and H. is partly based on the observation that
The summarized discussions that follow contain some of the >900 Chinook salmon stocks in
1) the rationale underlying the three proposed BC waters that are most prevalent in SRKW
Management Actions; 2) the scientific diets are also currently the most abundant
confidence of the workshop participants in the Chinook runs.
feasibility of implementing each Management A general consensus that fishery actions
Action, and whether it would provide the desired that focus on key stocks targeted by SRKW
benefit to SRKWs; 3) associated uncertainties would be more effective than general coast-
and unintended consequences associated with wide fishery reductions. Key stocks thought
each action; and 4) ways in which the actions to be most important to SRKW during spring
might be experimentally implemented to and summer are returning to Puget Sound
evaluate the effectiveness of each action, and (pre-May and post-Aug), the Fraser River
refine them as necessary. (May–Aug), lower southwest Vancouver
Island (Aug–Sep), and lower Strait of
Georgia (Aug–Sep). Puget Sound fish are
A: Increase abundance of Chinook coast-wide present during summer, but in lower
by reducing removals by fisheries proportions relative to Fraser Chinook.
Selectively reducing fishery catches (commercial Uncertainty about how many more fish
and recreational) throughout British Columbia SRKW need and could be provided by
would leave more fish in the ocean and thereby reduced fisheries given that about 600,000
increase the abundance of Chinook. However, it Chinook move through inside waters
is less certain which fish not taken by fisheries (300,000 Fraser River and 300,000 Puget
Availability of Prey for Southern Resident Killer Whales—Technical Workshop Proceedings 2018 • page 7Sound). Percentages of Fraser-bound fish increase by initially consuming more
caught before they enter the river is Chinook in terminal areas, and later preying
relatively low for some stocks, such as the on juvenile fish (in the case of seals)—with
5-year-old spring and summer Chinook unintended impacts on overall Chinook
(about 3–4%)—and higher for some 4-year numbers.
old fish (~25%). And finally, there may be challenges for
Recognition that not every fish saved from international coordination, and impacts to
fisheries will be available to SRKW due to First Nations and Indian tribes.
density dependent effects. It is not a linear
Despite these concerns, a few workshop
relationship, as seen after 1990 when ocean
participants favoured this Management Action—
fisheries were reduced in response to
on the premise that any precautionary measure
declines of wild Chinook runs. Returns of
was worth implementing, despite it having a low
some Chinook stocks increased following
probability of success.
fishery restrictions, while others did not.
Recognition that the percentage of spring In contrast to this belief, most participants
and summer Fraser Chinook caught in agreed that implementing sweeping changes
offshore mixed-stock commercial and lacking scientific justification would ultimately
recreational fisheries that are headed to prove counterproductive to efforts to recover
Juan de Fuca Strait is small. SRKW due to a lack of stakeholder and public
buy-in, and a potential perception that this
Recognition that in-season adaptive
action was based on political rather than
management would be difficult to
scientific considerations.
implement to make this an effective action.
It would likely be too late to close fisheries
in-season by the time it was recognized that B: Increase abundance of Chinook in specific-
salmon numbers of particular stocks areas and times by adjusting removals by
consumed by SRKW were low. Large fisheries
offshore aggregate fisheries are managed
This Management Action is also designed to
based on pre-season abundance forecasts
increase the abundance of 4-5+ year old Chinook
of Canadian and US stocks in those fisheries.
salmon of key stocks — but within “core SRKW
These forecasts are not updated in-season,
areas” at biologically appropriate times of the
and would be challenging to do so until
year. In other words, to increase the abundance
after fishing occurred.
of large Chinook salmon where and when SRKW
Increased availability of Chinook resulting are foraging.
from fishery closures may be partially offset
by removals by other predators (e.g., One means of increasing Chinook abundance
NRKW). In other words, SRKW may not during times that SRKW seek prey would be to
consume the fish left by fisheries. create refuges (or exclusion zones) over a
portion of SRKW critical habitat when SRKW are
The possibility of other unintended
expected to be present. Operationally, this might
consequences, whereby efforts to leave
be accomplished by imposing selective area
more Chinook in the ocean might increase
closures during specific months, and
the numbers of other consumers. For
redistributing fishing effort to places not used by
example, NRKW might be the ultimate
SRKW. The period of highest recreational fishing
beneficiaries of increased Chinook
use in Canada is from June to early September
abundance—and might ultimately encroach
(Father’s Day to Labour Day).
on SRKW habitat as their numbers increase.
Similarly, seals and sea lions might also Adjusting removals by fisheries in specific areas
used by SRKW at specific times of year was
Availability of Prey for Southern Resident Killer Whales—Technical Workshop Proceedings 2018 • page 8considered to have more merit than coast-wide There was some consensus that the abundance
fishery closures (Management Action A) for of Chinook that occurred in previous “good”
several reasons. Most notably, adjusting fishing SRKW years could provide a baseline measure of
effort by time and space is more likely to directly what targeted abundance should be. However,
increase the abundance of Chinook for SRKW at in the absence of this knowledge, it is unknown
specific times, and in specific areas where they what level of increase or stability is required to
are likely to forage. It would avoid the “dilution” measurably change SRKW condition or
effect of fishing in areas and at times “upstream” demographics. Some predictive models indicate
of where SRKW forage. a 30% rise in Chinook abundance is required—a
level approaching the “best” historic years—
In addition to an increased likelihood of
while other models indicate that a complete
providing greater benefits to SRKW, this type of
fishery closure would still be insufficient to
targeted fishery closure would likely have a
produce SRKW recovery, given the broad
lower socioeconomic impact than would broad
ecological and physical changes that have
(“upstream”) fisheries closures. Such an
occurred in the North Pacific Ocean.
approach would likely result in higher
stakeholder and public buy-in. Some uncertainty was also expressed in the
ability to identify which locations are most
An additional positive effect of selective fisheries
important, and what times of year are most
closures would be to alleviate potential physical
critical for SRKW.
and acoustic disturbance (see Management
Action C), although the ultimate benefit of this In considering this action, it was generally felt it
would depend upon the proportion of fishing should only be applied to:
vessels present relative to other vessels (which 1) Fisheries that catch a significant portion of
may be very low). the key stocks of 4+ Chinook sought by SRKW
Despite having more merit than Management (e.g., those that catch >5% of returning fish);
Action A, workshop participants ranked their 2) Fisheries whose catches consist of a high
scientific certainty of the effectiveness of proportion of 4+ year old Chinook (e.g., >10-
increasing Chinook numbers by adjusting fishery 20% of the fishery); and
removals within SRKW critical habitat to be low 3) Fisheries occurring within the time and high-
to medium. In general, the effectiveness of area- use areas of SRKW foraging (based on field
based closures was ranked low, while the observations of SRKW).
effectiveness of maximum size limits on fish
For commercial fisheries, these actions would
caught was ranked higher.
apply to locations with the highest Chinook
The uncertainty expressed over implementing catch. However, these areas are generally
this Management Action reflects several critical outside (to the north) of SRKW range (with the
unknowns, such as how much prey are required exception of Fishery Management Area 123).
for SRKW to meet their needs. It was unclear, for Similarly, the critical time for closures would
example, what the desired abundance of specific likely be during summer (but not exclusively)
Chinook stocks should be at specific times of when the greatest numbers of Chinook are
year. Using current “conditions” as a baseline caught.
was considered problematic because catches Ideally, closures of commercial and recreational
and abundance are lower now than they have fisheries would accommodate real time changes
been historically, while the number of other in the presence and absence of foraging SRKW.
competing predators consuming Chinook However, differences in the spatial and temporal
(including NRKW) are higher. scale at which recreational and commercial
fisheries operate make it more difficult to
effectively adjust recreational fishery removals
Availability of Prey for Southern Resident Killer Whales—Technical Workshop Proceedings 2018 • page 9of Chinook compared to adjusting commercial During winter, J pod can be found foraging in the
fishery removals in real time. An action that Strait of Georgia where Chinook winter
adapts to the daily movements of SRKW would abundance has been high over recent years (and
likely be too difficult to effectively communicate fishing effort low relative to summer months),
and logistically manage. The effectiveness of suggesting that fishing limitations may have
such an action would also likely prove to be too minimal additive benefit to J pod.
difficult to evaluate.
While fisheries might be adjusted to increase the
Additional questions were raised regarding how quantity of Chinook available, they might also be
SRKW might react to partial closures within their adjusted to increase the quality of individual
critical habitat. For example, would whales Chinook consumed (through size-limits that
bypass areas where fishing was occurring and leave bigger fish in the ocean). Body size of
concentrate foraging efforts in undisturbed Chinook has become smaller over time, which
areas where abundance is theoretically higher? means that each Chinook consumed by SRKW is
Similarly, would lots of Chinook in a noisy site now providing fewer calories on average than it
with lots of vessel disturbance be as effectively did in the past.
beneficial for SRKW as would feeding on a lower
Another point of consideration relates to the
abundance of Chinook in a quiet, undisturbed
predictability of foraging patterns of SRKW from
location? These questions highlight the
one year to the next. While SRKW are generally
considerable uncertainty about the relative
considered to be predictable in their annual
importance of Chinook abundance vs. the
movements, there can be considerable
accessibility of Chinook within an area. Killer
variability between years. Thus, the effective-
whales tend to spend a large proportion of time
ness of specific fishery closures under
in small areas, but it is unclear how big an area is
Management Action B is inherently limited by
required to be effective, or what degree of
the natural unpredictability of SRKW foraging
connectivity is needed between areas.
behaviour.
Field studies are planned to define SRKW
Given the foregoing uncertainties, workshop
foraging patterns and their relationship to
participants recognized that implementing this
fishing efforts. In the meanwhile, the picture is
(or any) Management Action must be done
far from clear.
experimentally (with a statistically appropriate
Implementing this Management Action would experimental design), so that the effectiveness
be complex given that the three pods of the of the action can be evaluated and adaptively
SRKW population (J, K and L) use different changed as required. This would entail
foraging areas, and are not equally dependent evaluating the effectiveness of specific closures
on the same Chinook stocks. on an ongoing basis, and suitably adjusting the
specific implementation of this Management
For example, K and L pods feed during winter off
Action as necessary. Specific monitoring would
the US west coast down to California. The stocks
be required to ascertain the effect of this action
important to these two pods vary in size and
on Chinook abundance and SRKW foraging
robustness (Klamath, Columbia, and coastal
behaviour within specific areas.
Chinook salmon stocks). The potential to
mitigate numbers of Chinook belonging to the Determining whether restrictions placed on
different stocks through control of fisheries is fishery catches have positive effects on SRKW is
also likely to prove unfeasible. It was noted, for problematic. Determining whether foraging
example, that stocks in southern California are at success improves will require concurrent studies
dire numbers, and there are few immediate of salmon movements and SRKW foraging
options to revitalize these stocks, either through efficiency (using longer-term observations and
fisheries management or other actions. underwater tracking technologies).
Availability of Prey for Southern Resident Killer Whales—Technical Workshop Proceedings 2018 • page 10While the ultimate goal of this action is to rates. This Management Action would
improve the population dynamics of SRKW by specifically minimize acoustic interference with
increasing their birth rates and reducing death echolocation during hunting and communication
rates, such measures of population recovery between pod members, and would minimize
may respond on time scales that are too long to physical interference from vessels that may
be linked to the proposed actions. disrupt surface chases, preclude prey sharing, or
cause animals to cease foraging and move out of
Estimates of SRKW body condition were
an area. One model suggests that increasing the
generally felt to be a more useful short-term
accessibility of Chinook salmon (i.e., the ability of
metric of nutritional status of individual whales,
SRKW to catch them) by 30-50% would
with the caveat that changes in physical
significantly improve the demographics of
condition can be caused by a number of factors
SRKW.
(such as disease) and are not necessarily
indicative of inadequate prey. Nevertheless, This proposed action to minimize the negative
correlating metrics of SRKW health (body effect of vessels on SRKW incorporates 1) vessel
condition, hormones) with salmon abundance exclusion zones in key foraging areas (akin to
could help to identify when salmon abundance is Management Action B), and 2) a protective
too low and fisheries need to be restricted. exclusion zone around SRKW at all times.
Obtaining aerial images of SRKW returning in Workshop participants recognized that it is
May, and again in the fall will provide essential unrealistic to close all potential SRKW foraging
monitoring data on changes in body condition areas at all times. However, they emphasized the
relative to the abundance of Chinook. need for quality data to make decisions about
which areas should be closed, and at which times
Implementing this Management Action would
of year to do so. Implementing this action
require continued studies of SRKW diet and
requires a rigorous experimental design to
foraging behaviour (times and locations) to
evaluate its effectiveness.
inform the management of key Chinook stocks
important to SRKW at the proper times of year. It was further recognized that SRKW often forage
It would also require implementing an adaptive in the presence of many vessels (recreational
management strategy, with annual evaluations and commercial fishing, whale watching, and
of winter and summer SRKW distributions and recreational vessel traffic). Given this overlap
stock-specific Chinook abundances. between vessels and SRKW, this action would be
minimally effective if it is only applied to fishing
vessels because numbers of fishing vessels are
C: Increase accessibility of Chinook by
believed to be relatively small compared to other
decreasing acoustic & physical disturbances
types of vessels (although significant numbers of
Some workshop participants felt the accessibility fishing vessels may gather in prime areas at
of Chinook in areas where SRKW forage would be certain times). It is not clear how challenging it
significantly increased if 1) disturbances caused might be to implement this action for different
by the presence of vessels was reduced by 50%, classes of vessels from a regulatory view,
and if 2) disturbances caused by underwater involving multiple legislative changes (i.e.,
noise from vessels were reduced by 100%. Other Fisheries Act, Transport Canada, etc.).
workshop participants merely wanted significant
There was general consensus that a 200 m
reductions without specifying target levels.
exclusion zone was reasonable — despite the
Reducing the frequency of physical and acoustic
scientific questions surrounding the biological
disturbances would theoretically facilitate SRKW
effectiveness of this distance (a portion of the
being more successful at capturing prey—
participants suggested a more precautionary
thereby allowing them to be in better physical
400 m zone, but no one suggested a distance less
condition and have higher survival and birth
Availability of Prey for Southern Resident Killer Whales—Technical Workshop Proceedings 2018 • page 11than 200 m, which is the approach distance whales. Although whales might be expected to
currently required in the United States). This avoid such noisy corridors and move to less
Action would theoretically provide “bubble” disturbed areas, the presence of salmon may
protection around whales as they move into motivate them to stay put.
known foraging areas.
Finally, while the intent of this Management
Unfortunately, building a moving bubble around Action is to improve the foraging of SRKW by
SRKW has its limitations, even when perfectly making it easier for SRKW to catch the fish that
implemented. For example, it would not prevent are present, it would likely have to be
whales from moving into a foraging area where implemented for all killer whales (transient and
vessels are already present. While regulations resident) because it is unrealistic to expect
would prevent approaching the whales closer operators to readily distinguish between the two
than 200 m, it cannot legislate against whales ecotypes of killer whales.
moving towards vessels and exposing
Workshop participants ranked the scientific
themselves to vessel noise and movements that
certainty that reducing physical and acoustic
may degrade their foraging environment. Nor
disturbances by vessels would significantly
would operators necessarily be required to limit
increase the accessibility of Chinook for SRKW as
their acoustic footprint if they are already in the
medium to high.
area.
This range in certainty is higher than the other
One means of reducing the potential for vessels
two Management Actions considered, and
to affect the ability of SRKW to access Chinook
reflects the extent and importance of knowledge
would be to require them to pull their gear and
gaps. While there was an accepted link between
turn off their fish finders or engines (if safe to do
noise and poor foraging success, the dose-
so) should whales approach within a specified
response of SRKW foraging behaviour in relation
distance within identified foraging areas. Speed
to vessel noise and numbers was less clear.
restrictions could also be implemented within
Other identified potential knowledge gaps
critical foraging areas used by SRKW.
include sound profiles of critical areas, and
As a side note, it was mentioned that the diurnal pattern of SRKW foraging. It was felt that
majority of recreational Fishfinders operate at these questions could be clarified through
two frequencies (50 and 200 kHz), and are preset further studies, while the exclusion zone should
to the lower frequency that has a broader and be experimentally implemented. Despite these
deeper cone of ultrasound coverage than the gaps, vessel exclusion zones were generally felt
higher frequency. The hearing range of killer to be a prudent measure.
whales extends from ~0.6 KHz to >100 kHz, with
The efficacy and design of exclusion zones can
the greatest sensitivity between 20–50 kHz. To
only be improved through intensive monitoring
avoid potential impacts within the hearing range
during implementation. Operator compliance
of SRKW, manufacturers or users could preset
evaluations could include AIS (Automatic
their devices to the higher 200 kHz frequency to
Identification System) monitoring, cameras and
prevent overlap with the SRKW dynamic range,
radar. As has been demonstrated in other
and users could be educated about using the
marine programs, education of vessel operators
higher setting around whales.
(particularly recreational) is often as important
Mediating vessel behaviour when killer whales as regulatory enforcement. Specific guidance
approach them is particularly problematic in would also likely be required for those fishing
transportation corridors within SRKW critical (target messaging in key areas such as Salmon
habitat that have high numbers of moving Bank), and perhaps as part of licensing
vessels. Under such circumstances, there seems procedures.
little chance of creating a “quiet zone” for the
Availability of Prey for Southern Resident Killer Whales—Technical Workshop Proceedings 2018 • page 12The biological effectiveness of this action on significantly increase the ability of SRKW to catch
SRKW would have to be closely monitored. the salmon that are present in foraging areas.
While this action is likely to improve targeted
foraging opportunities for SRKW, it is unclear Measuring Efficacy of Actions
what effect it will have on their well-being.
There are a number of performance measures
Evaluating the efficacy should include potential
that can be used to assess the effectiveness of
short-term effects such as behavioural measures
(e.g., the amount of time whales spend in Management Actions on SRKW. However, each
feeding areas), the acoustic levels within those requires a commitment to data collection and
areas, and an analysis of foraging success vs. analyses, and forethought about how to
acoustic profiles, and longer-term studies on interpret them. Possible metrics include:
changes in physical condition and hormone
Body Condition. Aerial photographs of SRKW
profiles of SRKW.
retuning in May, and again in the fall will provide
In addition to implementing an experimental essential monitoring data on changes in body
framework to evaluate the benefit of areas of condition relative to the abundance and
action versus no action, restricting the accessibility of Chinook during spring and
movement and presence of vessels should be summer, as well as relative measures of feeding
done adaptively. This would entail establishing
conditions during winter when the SRKW are
connections between SRKW health and Chinook
believed to be primarily along the outer coast of
abundance (e.g., scenarios indicate suite of
options for high Chinook/low whale condition, the United States. An invaluable database of
low Chinook, etc.). body conditions has grown in recent years, but is
not yet sufficient to determine an ideal body
condition or what a significant improvement
Conclusions looks like.
What Actions to Take
The four discussion groups had evenly balanced Table 1. Scientific justifiability of the Management
expertise on killer whales, Chinook salmon and Actions and the likelihood that they would provide
fisheries management — and came to similar the desired benefit to SRKWs. Note that the
conclusions about the scientific justifiability of likelihood of success correlated positively with
the Management Actions considered, and the scientific justification — “?” represents unknown.
likelihood that they would provide the desired Scientific Justifiability
Management Action
benefit to SRKWs (Table 1). ? Low Med High
Overall, there was little confidence (unknown– A. Increase abundance
low) that reducing fishery catches coast-wide of Chinook coast-wide
X X
by reducing removals
would benefit SRKW, and slightly more
by fisheries
confidence (low–med) that restricting catches
B. Increase abundance
within specific areas of SRKW critical habitat
of Chinook in specific-
would significantly increase Chinook abundance. X X
areas & times by adjust-
ing fishery removals
In contrast to doubts about being able to
significantly increase the numbers of fish in C. Increase accessibil-
SRKW habitat, there was greater confidence ity of Chinook by
X X
decreasing acoustic &
(med–high) that reducing acoustic noise and physical disturbances
physical disturbances by vessels would
Availability of Prey for Southern Resident Killer Whales—Technical Workshop Proceedings 2018 • page 13Physiological Status. Significant advances have interval between calving times, increasing
been made in developing ways to assess the success at age of first reproduction, and
well-being of free-swimming whales. Fecal increasing reproductive potential (improved age
samples, respiratory (blow) samples, blubber & sex composition of pods). However, changes in
biopsies, and skin samples are increasingly used reproduction and survival rates occur over
to assess health, nutritional status, exposure to relatively long periods and are unlikely to be
disease, stress levels, and reproductive status. useful or dependable measures of the
Validation of methodologies to assess and immediate effects of the actions considered.
interpret physiological status relative to
environmental conditions (i.e., perceived Future Refinement and Planning
stressors) is ongoing. This workshop was an important first step in
Area Use. The percentage of time a whale bringing fisheries managers and killer whale and
spends in particular areas is likely to be a useful Chinook salmon experts together to identify and
metric. This is based on the assumption that evaluate short-term management actions that
more time moving between areas is indicative of might be taken to increase the immediate
lower available prey—while less travelling is abundance and accessibility of Chinook salmon
presumed to reflect relatively good foraging. for SRKW, given the current size of Chinook
stocks.
Activity Budgets. The percentage of time killer
whales engage in resting, foraging, travelling, As a next step, a smaller group of managers and
and socializing is presumed to reflect feeding scientists with expertise in killer whales and
conditions—as it has been observed that killer Chinook could develop detailed strategies,
whales typically travel more and forage less in design the experimental implementations and
bad salmon years and in the presence of vessels required analyses to ensure the effectiveness of
(they also tend to do less resting and socializing). the actions taken to improve the status of
southern resident killer whales.
Acoustic Behaviour. Foraging activity could be
captured by hydrophones. Changes in the
frequency of calls between SRKW might reflect
changes in feeding conditions.
Acknowledgements
The workshop was supported through Fisheries
Foraging Success. Individual SRKW might be and Oceans Canada’s Ocean and Freshwater
followed from shore or from a distance on the Science Contribution Program awarded to
water to document successful prey captures. Andrew Trites and Brian Hunt at the UBC
Suction-cup electronic tags that record Institute for the Oceans and Fisheries. We are
underwater behaviours can be attached for brief grateful for the logistical support provided by
periods to determine where, when and how Pamela Rosenbaum (UBC Marine Mammal
frequently SRKW catch Chinook and whether Research Unit), and for the rapporteur support
they are more successful following from Madeline Young (International Year of the
implementation of the Management Action. Salmon). We are also grateful to Earth and
Reproduction & Survival. The overall goal of all Oceans Sciences, and to the Institute for the
the Management Actions considered during this Oceans and Fisheries for providing meeting
workshop was to support SRKW recovery by rooms.
ultimately increasing the number of female
calves, increasing calf survival, reducing the
Availability of Prey for Southern Resident Killer Whales—Technical Workshop Proceedings 2018 • page 14Appendix A: Participants
Lynne Barre US National Marine Fisheries Service lynne.barre@noaa.gov
Lance Barrett-Lennard Ocean Wise lance.barrett-lennard@ocean.org
Penny Becker Washington Dept of Fish and Wildlife penny.becker@dfw.wa.gov
Gayle Brown Fisheries and Oceans Canada gayle.brown@dfo-mpo.gc.ca
Sean Cox Simon Fraser University sean_cox@sfu.ca
Thomas Doniol-Valcroze Fisheries and Oceans Canada thomas.doniol-valcroze@dfo-
mpo.gc.ca
John Durban US National Marine Fisheries Service john.durban@noaa.gov
Peter Dygert US National Marine Fisheries Service peter.dygert@noaa.gov
Holly Fearnbach SR3 hfearnbach@sealifer3.org
Mike Ford US National Marine Fisheries Service mike.ford@noaa.gov
John Ford University of British Columbia john.ford@ubc.ca
Jeff Grout Fisheries and Oceans Canada jeff.grout@dfo-mpo.gc.ca
Brad Hanson US National Marine Fisheries Service brad.hanson@noaa.gov
Marla Holt US National Marine Fisheries Service marla.holt@noaa.gov
Kirt Hughes Washington Dept of Fish and Wildlife kirt.hughes@dfw.wa.gov
Brian Hunt University of British Columbia b.hunt@oceans.ubc.ca
Lisa Jones Fisheries and Oceans Canada lisaann.jones@dfo-mpo.gc.ca
Chris James NW Indian Fisheries Commission cjames@nwifc.org
Ruth Joy SMRU Consulting rj@smruconsulting.com
Peter Katinic Fisheries and Oceans Canada peter.katinic@dfo-mpo.gc.ca
Robert Kope US National Marine Fisheries Service robert.kope@noaa.gov
Karen Leslie Fisheries and Oceans Canada karen.leslie@dfo-mpo.gc.ca
Wilf Luedke Fisheries and Oceans Canada wilf.luedke@dfo-mpo.gc.ca
Marla Maxwell Fisheries and Oceans Canada marla.maxwell@dfo-mpo.gc.ca
Teresa Mongillo US National Marine Fisheries Service teresa.mongillo@noaa.gov
Jennifer Nener Fisheries and Oceans Canada jennifer.nener@dfo-mpo.gc.ca
Dawn Noren US National Marine Fisheries Service dawn.noren@noaa.gov
Availability of Prey for Southern Resident Killer Whales—Technical Workshop Proceedings 2018 • page 15Jan Ohlberger University of Washington janohl@uw.edu Martin Paish Sport Fishing Institute of BC mpaish@sportfishing.bc.ca Brian Riddell Pacific Salmon Foundation briddell@psf.ca David Rosen University of British Columbia rosen@zoology.ubc.ca Teresa Ryan University of British Columbia teresa.ryan@ubc.ca Bryan Rusch Fisheries and Oceans Canada bryan.rusch@dfo-mpo.gc.ca Mei Sato Oregon State University msato@coas.oregonstate.edu Mark Saunders International Year of the Salmon msaunders@yearofthesalmon.org Sharlene Shaikh Fisheries and Oceans Canada sharlene.shaikh@dfo-mpo.gc.ca Eva Stredulinsky Fisheries and Oceans Canada estredulinsky@gmail.com Jennifer Tennessen US National Marine Fisheries Service jennifer.tennessen@noaa.gov Mary Thiess Fisheries and Oceans Canada mary.thiess@dfo-mpo.gc.ca Sheila Thornton Fisheries and Oceans Canada sheila.thornton@dfo-mpo.gc.ca Andrew Trites University of British Columbia a.trites@oceans.ubc.ca Bob Turner US National Marine Fisheries Service bob.turner@noaa.gov Eric Ward US National Marine Fisheries Service eric.ward@noaa.gov Rob Williams Oceans Initiative rob@oceansinitiative.org Brianna Wright Fisheries and Oceans Canada brianna.wright@dfo-mpo.gc.ca Madeline Young International Year of the Salmon myoung@yearofthesalmon.org Availability of Prey for Southern Resident Killer Whales—Technical Workshop Proceedings 2018 • page 16
Appendix B: Agenda Availability of Prey for Southern Resident Killer Whales—Technical Workshop Proceedings 2018 • page 17
Availability of Prey for Southern Resident Killer Whales—Technical Workshop Proceedings 2018 • page 18
Availability of Prey for Southern Resident Killer Whales—Technical Workshop Proceedings 2018 • page 19
Appendix C: Participant Presentation Summaries
The following synopses of workshop presentations were provided by participants, and have been
edited for style.
November 15, 2017 1. High proportions of physically mature
Day 1 – Prey Requirements of Southern males &/or lactating females in the
Resident Killer Whales (SRKW) groups (i.e. nutritionally-needy
individuals)
A. SRKW status and demographic update (Eric
Ward, NWFSC) 2. Leadership capacity within the group
SRKW are likely to continue to decline. (i.e. multiple old, mature females)
How quickly that happens depends on 3. Lower maternal relatedness among
what assumptions we make about future group members (this can occur
environmental conditions, sex ratios at through deaths of common ancestors
birth being different from 50:50, potential as well as group growth)
effects of inbreeding, and other factors Prey sharing is a prevalent behaviour in
that reduce fecundity or survival. RKWs, where animals share prey with
SRKW are an anomaly in that they are the their closest maternal relatives
only killer whale population in the NE - Adult RKW females are the primary
Pacific that hasn't increased exponentially. provisioners of their groups, sharing
This is true since the 1970s, including the consistently even in years of low
period since the last 2011-2012
salmon abundance (which makes
workshops.
them particularly vulnerable to food
As noted in the last independent panel
shortages).
report and work since, there is increased
- Adult males share the least with their
opportunity for competitive effects of
other killer whale populations on SRKW group. This is likely because they have
(NRKW in particular have spatial overlap huge caloric requirements and they
with SRKW). are also the least maternally related
Recent trends in SRKW appear to be (on average) to their group.
somewhat decoupled from aggregate While a mother’s provisioning of her
salmon indices. In the last 5-10 years, daughters stops at daughter’s
salmon indices have been at or near reproductive maturity, sons are
historic highs and these periods have seen provisioned throughout their lifetime
high population growth of other killer - Adult males depend on close female
whales. But the trajectory for SRKW is relatives to be provisioned, and, in the
somewhat opposite. absence of such relatives, their
survival decreases. This relationship is
B. Influence of sociality on the prey needs of especially apparent in years of low
Southern Resident Killer Whales (Eva salmon abundance.
Stredulinsky, DFO)
Relevant notes from outside of this
Splitting of RKW groups is correlated to presentation:
coast-wide Chinook abundance - According to SRKW photogrammetry
This relationship is amplified by: work (J. Durban, H. Fearnbach et al.),
while adult males have females
Availability of Prey for Southern Resident Killer Whales—Technical Workshop Proceedings 2018 • page 20provisioning them, they consistently D. Coastal occurrence of SRKWs based on
have the best body condition of all sightings and acoustic data (Ruth Joy, SMRU
age-sex classes. So it seems, in Consulting)
general, they are only vulnerable to Project goals
food shortages when they are lacking 1. To better understand the fine-scale
older female animals to provision spatial and temporal distribution of
them. SRKW during “Chinook season” (May-
October), focusing on current and
C. Killer whale genetics, and paternity in the proposed Canadian Critical Habitat.
southern resident population (Michael 2. To better understand where foraging
Ford, NOAA) occurs.
Main points Multiple datasets: some opportunistic
The whales have highly skewed male presence only, some more systematic with
reproductive success – ~50% of the associated effort.
current population descended from just One of the key datasets was collected by
two males Brian Gisborne with 2887 tracklines of
Four apparent cases of close inbreeding effort distributed across 815 days. He
(2.5% of all inferred matings) observed SRKW 158 times across effort
Less close inbreeding is certainly mostly concentrated in the
occurring, but hard to detect with spring/summer/fall months.
current data The 2nd key source of data is that from the
BCCSN and OrcaMaster datasets. These
Consequences of inbreeding in the
are presence only datasets for which we
population still under study - will have
will have to derive either a pseudo effort
results next year
datalayer from absence data, or else a
No evidence of inbreeding avoidance presence only approach. We’d like to
Population has had low effective size avoid making assumptions about ‘effort’.
(~25) for at least several generations The overarching methodological plan is to
Implications for prey conservation/use fit a Bayesian spatial-temporal model
Old, large males are important and they using approximate methods (instead of
need a lot of food, but the population particle MCMC) to estimate the
probability of SRKW presence in the Salish
may not need very many of them
Sea in the months from May to October.
Inbreeding depression may mean
We will be incorporating as much data as
population needs more prey than a
we can (scared about the Chinook data
comparable outbred population now though!!), with the intent to start
Based on the work by Eva Stredulinksy, with integrating Brian’s data with the
the whales seem to put a lot of resources sightings databases.
into males, and this seems almost Deliverable date is March 2018.
maladaptive from a population
perspective even if it perhaps makes
sense from an individual whale
perspective
Availability of Prey for Southern Resident Killer Whales—Technical Workshop Proceedings 2018 • page 21E. Coastal occurrence of southern resident G. Dtags as a tool for behavioural studies of
killer whales based on satellite tagging and resident killer whales (Brianna Wright,
acoustic recorder detections (Brad Hanson, DFO)
NWFSC)
See: Wright, B.M., Ford, J.K.B., Ellis, G.E.,
Acoustic recorder detections and satellite- Deecke, V.B., Shapiro, A.D., Battaile, B.C. &
linked tag location data from SRKW have Trites, A.W. 2017. Fine-scale foraging
provided a much more complete picture of movements by fish-eating killer whales
SRKW fall, winter, and spring occurrence (Orcinus orca) relate to the vertical
Acoustic recorder detection data showed distributions and escape responses of
that the area near the Columbia River was salmonid prey (Oncorhynchus spp.).
used much more than expected by K/L Movement Ecology 5:3.
pods
Satellite tagged members of K and L pods H. Acoustic cues recorded from animal-borne
ranged from Cape Flattery, Washington to tags to quantify foraging events in
Pt. Reyes, California, remaining on the endangered fish-eating killer whales (Marla
continental shelf, and generally close to Holt, NWFSC)
the coast 34% of dives contained echolocation click
High use sites for K/L pods included areas bouts
off the Columbia River and Gray’s Harbor, The majority of click bouts were slow
northern California, and the northern clicks on repeated shallow dives,
Olympic Peninsula interpreted as searching for prey at the
K/L pods primarily occur in a relatively surface. This makes SRKW vulnerable to
narrow band of the continental shelf near vessel masking noise and boat presence
the coast Dive depth and year were important
Satellite tagged members of J pod ranged explanatory variables of click presence
from the continental shelf waters of the Co-occurrence of buzzes and prey
central west coast of Vancouver Island to handling sounds indicate prey capture
northern Georgia Strait Males had higher presence of buzz and
High use sites for J pod included northern prey handling sounds on per dive basis,
Georgia Strait and the western end of Juan consistent with having higher feeding
de Fuca Strait rates to support a larger total body size
K/L and J pods appear to have nearly Integration of the acoustic data analysis
exclusively separate winter ranges results with other tag sensor data is
In general, SRKWs appear to display critical input for the development of the
similar range and site fidelity patterns foraging detector, presented by J.
between years Tennessen
Results ultimately will be used to predict
foraging in order to determine vessel and
F. Assessment of potentially important SRKW
habitat outside of designated Critical noise effects on behavior, including
Habitat (John Ford, DFO & UBC) different phases of foraging that involve
the use of sound
No summary provided
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