The optimism of early salmon hatchery practitioners to increase abundance (Lichatowich 1999) has been tempered in recent decades by theoretical and empirical studies indicating unintended negative effects hatcheries
can have on wild Pacific salmon and steelhead (Naish et al. 2008; Pearsons and Temple 2010).
Unintended
effects of hatcheries are much more difficult and costly
to assess than evaluating the benefits of hatchery production to provide harvest opportunities. Holistically
evaluating the relative costs and benefits of past and
current hatchery practices requires an understanding and
estimation of the unintended effects (Pearsons 2010). In
recent years, national and local governments, indigenous (e.g. First Nations or tribal) resource agencies, private
industry and NGO conservation groups have begun
efforts to reform public salmon and steelhead hatchery
systems in North America, which include critically evaluating societal and biological risks and benefits.
A significant number of national and international
policy concerns and actions are directly relevant to this
issue. In the US Pacific Northwest, for example, the
National Oceanic and Atmospheric Administration
(NOAA) is currently evaluating the environmental
impact of salmon and steelhead hatcheries through
federal mandates such as the Endangered Species Act
and the Mitchell Act. The US State of Alaska is faced
with ongoing challenges of adhering to the States
fisheries policies regarding sustainability, genetics
and escapement goals in the face of a growing private
salmon hatchery industry in the State. In Canada, the
Department of Fisheries and Oceans (DFO) is in the
process of implementing an ambitious new Wild Salmon
Policy that must address impacts hatcheries have on wild
salmon. There is fresh thinking and emerging new
initiatives in both Japan and Russia to identify and
separately manage wild salmon in these nations.
The growing demand for sustainable seafood has
put the global spotlight on salmon, which is near the
top of the list of most desired seafood, buoyed by
reports of health benefits of eating salmon. Third party
sustainability certifications of wild capture fisheries is
required in many global markets, and Pacific salmon fisheries are coming under increased international
scrutiny with respect to how salmon hatcheries are
managed and the degree to which hatchery salmon
interact with and affect wild salmon, both genetically
and ecologically (Peterman 2002; Chaffee and Bosworth
2007). Salmon populations (comprised of both wild
or hatchery populations, or a mixture of the two) also
continue to play a critical role in supporting subsistence,
ceremonial and recreational fisheries across the North
Pacific region.
The effects of hatchery-produced salmon on aquatic
ecosystems have been vigorously debated in academic
and natural resource forums and in the scientific literature. The attention to hatchery effects has resulted in
coordinated efforts to reform the public hatchery system
in the United States and led to very specific guidelines to
mitigate genetic impacts (Mobrand et al. 2005; Paquet et
al. 2011). Although genetic interactions have received
most of the attention in the scientific literature (Waples
1991; Araki et al. 2008; Fraser 2008; Christie et al.
2011), negative associations between the numbers of
hatchery fish released and wild salmon survival rates
have been hypothesized to be the result of ecological
interactions (e.g., Nickelson 2003). Indeed, a number of
recent reviews highlight the potential importance and
gaps in our understanding of the ecological effects of
hatchery salmon on wild salmon populations and their
freshwater and marine habitats (Naish et al. 2008;
Pearsons 2008). In 2009, a small group of scientists and
policy makers recognized the need and value of convening a diverse group of experts and stakeholders to
describe what is known about the scale and magnitude
of ecological interactions between wild and hatchery
salmonids, and to describe a logical path forward to
address unintended effects hatchery salmonids can have
on wild salmonids throughout their native range in the
North Pacific.
The papers contained in this volume are a product of
convening experts and stakeholders at a conference
entitled Ecological Interactions Between Wild and
Hatchery Salmon. The meeting was organized by State
of the Salmon and held on 47 May 2010 in Portland,
Oregon, USA. Our conference aimed to present the
most current information about ecological interactions,
identify critical scientific uncertainties, identify available tools for managing ecological risks, and to develop
a path forward for improving the understanding and
management of ecological interactions between wild
and hatchery salmonids in the North Pacific region. The conference was the first pan-Pacific event designed to
explore the scale and magnitude of the ecological effects
of salmon and steelhead hatcheries. Over 300 people
attended the meeting and participants in the conference
hailed from the United States, Canada, Russia, and
Japan. The conference agenda included 47 talks and
was organized into seven separate sessions. This special
journal issue represents 23 original scientific investigations and reviews on ecological interactions. We also
encourage the reader to visit the conference website
(http://www.stateofthesalmon.org/conference2010/) for
additional information.
The agenda and expected outcomes from the
conference were shaped by a steering committee composed of agency and academic experts from the United
States, Canada, Russia and Japan. The steering committee members were as follows (listed in alphabetical
order):
- Brian Allee, NOAA
- Barry Berejikian, NOAA
- Stephen Brandt, Oregon Sea Grant
- Dan Bottom, NOAA
- Craig Busack, Washington Department of Fish and Wildlife
- Ken Currens, Northwest Indian Fisheries Commission
- Robert Devlin, Department of Fisheries and Oceans, Canada
- Ian Fleming, Memorial University
- Susan Hanna, Oregon State University
- Masahide Kaeriyama, Hokkaido University
- David Noakes, Oregon State University
- Ken Ostrand, U.S. Fish and Wildlife Service
- Todd Pearsons, Grant County Public Utility District
- Pete Rand, State of the Salmon
- Bill Smoker, University of Alaska Fairbanks (retired)
- Alex Wertheimer, NOAA (retired)
- Lev Zhivotovsky, Institute of General Genetics, Russian Academy of Sciences
While we sought to encourage wide ranging participation and perspectives at the conference, the guest
editors wish to emphasize that any views or suggestions
expressed in this special issue are not intended to represent the views of any particular salmon management
entity whose jurisdiction includes the North Pacific. We
do hope, however, that views and perspectives expressed are thought provoking and help spur meaningful dialogue toward an important goal of conserving
wild salmon.
The structure of this special issue addresses the ecological interactions between wild and hatchery salmon
and steelhead as a life history progression across ontogenetic stages and habitats. In addition, a number of review
and perspective papers were presented at the conference.
Below we provide an overview on the unique contribution made by each of the authors in this special issue.
We began by examining interactions occurring in the
early life history of Pacific salmon and steelhead in
freshwater. A review of juvenile salmon competition
described how factors including duration of freshwater
cohabitation, relative body size, prior residence, and
species differences all influence competitive interactions, with fish density in relation to habitat carrying
capacity likely exerting the greatest influence (Tatara
and Berejikian 2012, this issue). Another review described evidence of predation by stocked hatchery steelhead on juvenile wild salmon (Naman and Cameron
2012, this issue) exemplifying the variability in predation
rates that can be associated with timing of emergence and
hatchery release practices. This paper provided practical
suggestions on how to minimize predation risk through
hatchery management changes. Manipulation of growth
regimes in steelhead hatchery facilities to induce more
natural life history expression and minimize negative
effects on wild fish further exemplified efforts to reform
hatchery practices to minimize predation and competition risks of released steelhead trout during their freshwater residence (Berejikian et al. 2012, this issue).
A unique modeling tool (PCD Risk 1) has been developed for conducting risk assessment and facilitating risk
reduction associated with predation, competition and disease among salmonids in freshwater environments
(Pearsons and Busack 2012, this issue). Methods to manage ecological risks of a hatchery program in the US State
of Washington were used to reduce adverse impacts to a
variety of non-target taxa, which are frequently overlooked
(Temple and Pearsons 2012, this issue). And, a broad scale
risk assessment approach using the PCD Risk 1 model and
expert based opinion is described for the Upper Columbia
River, USA/Canada (Pearsons et al. 2012, this issue).
Following the freshwater juvenile stage, smolts
originating from natural spawning habitat and hatcheries may differ in their early marine life histories but
may still compete during their seaward migration.
Wild and hatchery chum salmon in inlet and near
shore habitats in Southeast Alaska, USA partitioned
diets and habitat resources, which suggests transitory
effects of density-dependent competition between wild and hatchery chum salmon during the early marine phase of the life cycle (Sturdevant et al. 2012, this
issue). A similar study on Chinook salmon in waters
off the coast of the US States of Oregon and Washington showed less differentiation in diet and habitat
use among wild and hatchery individuals, with evidence that both populations responded synchronously
to ocean conditions (Daly et al. 2012, this issue). A
study in coastal British Columbia suggests wild Chinook salmon may be more resilient to future climate
change than their hatchery counterparts given observations of higher near shore survival of wild postsmolts (Beamish et al. 2012, this issue). There remains
substantial uncertainty regarding the interpretation of
spatial, temporal, and dietary overlap between hatchery and wild fish during their early life history in the
marine environment, but these studies have provided a
starting point for understanding some of the conditions
under which overlap can occur, the degree of overlap
in different regions, and some initial interpretations of
its significance.
Less is known about the offshore marine life history
of Pacific salmon. However, two papers in the special
issue have lifted the curtain on the potential interactions occurring between wild and hatchery salmon in the
open ocean. An increase in Asian hatchery chum salmon
abundance from 10 million to 80 million fish may have
influenced body size, age-at-maturation, productivity
and abundance of a distant wild chum salmon population
in Norton Sound, Alaska (Ruggerone et al. 2012, this
issue). Growth and survival of North Pacific salmon are
declining as a result of competitive interactions among
salmon at sea, a process that may be exacerbated by
hatchery programs for pink and chum salmon and future
climate change (Kaeriyama et al. 2012, this issue).
A number of studies addressed interactions occurring
at the time of adult return migration and spawning.
Recent research was presented on straying of hatchery
produced pink, chum and sockeye salmon in Prince
William Sound, Alaska. This helps frame some of the
challenges in minimizing adverse effects of hatchery
populations on wild salmon in this region (Brenner et
al. 2012, this issue). The first comprehensive salmon
escapement survey of chum salmon in Hokkaido, Japan,
provided evidence of natural reproduction in a region
that has focused for many decades on hatchery development (Miyakoshi et al. 2012, this issue). The unique
history of hatchery development in Sakhalin, Russian
Federation and the emerging understanding of interactions between wild and hatchery pink and chum
salmon provides insight into potential competition
between wild and hatchery salmon in this region (Kaev
2012, this issue). New evidence was presented on trait
divergence between wild and hatchery populations of
chum, Chinook and sockeye populations in southern
Kamchatka, Russian Federation and the first documentation in the literature on the contribution of hatchery chum
salmon to the natural spawning population of chum
salmon in this region (Zaporozhets and Zaporozhets
2012, this issue).
Three additional papers address reproductive interactions and demonstrate the power of genetic tools in
understanding the nature of ecological interactions between wild and hatchery salmon. Shifting demographics
of hatchery Chinook salmon populations to earlier male
maturity may influence overall DNA pedigree-based
estimates of reproductive success in natural populations
supplemented with hatchery-reared Chinook salmon
(Schroder et al. 2012, this issue). A study of genetic
markers reveals how a rare lake-type chum population
is being swamped by a rapidly expanding hatchery chum
salmon population in a small island in the Kurile archipeligo, Russian Federation (Zhivotovsky et al. 2012,
this issue). Genetic differences among cultured and
wild populations of masu salmon in Hokkaido, Japan
were highlighted in another study, and the authors
urged fisheries managers to consider the risk of fitness loss in wild masu populations that might interbreed with hatchery fish (Yu et al. 2012, this issue).
A number of broad reviews were presented on different dimensions of the conference theme. A succinct summary of enhancement of Alaska salmon fisheries noted
many of the positive benefits to the fishery and the state
(Heard 2012, this issue). A summary of five case studies
provides a rich description of the history, ecological
dimensions, and the interplay between emerging scientific
information and the creation of public policy in the US
Pacific Northwest context, concluding with some practical suggestions on how to effectively contain risks in the
future (Kostow 2012, this issue). A cogent argument for
developing and implementing a new wild salmon policy
in Japan was introduced (Nagata et al. 2012, this issue),
emphasizing reforms needed to conserve remaining
natural reproductive components of Japanese salmon
and to restore degraded salmon habitat. Theory and
empirical studies highlight the risks of hatchery fish
eroding the potential for adaptation in wild salmon,
and underscores the importance of protecting wild populations to achieve sustained harvests of Alaskan
salmon (Grant 2012, this issue). Finally, a regional
synthesis paper summarizing the state of understanding
of ecological interactions across the diverse North Pacific region highlighted efforts underway or planned to
increase our understanding and identify needed actions
to minimize negative effects in the context of fisheries
management (Rand et al. 2012, this issue).
We were encouraged by the positive testimonials that
we received during and following the conference. We hope
that this special issue will further inspire collaboration
among scientists, managers, conservationists, indigenous
peoples, fishers, business people, and politicians and serve
as a long-term record of the conference. Furthermore, our
hope is that through collaboration we can increase our
understanding and advance the management of ecological
interactions so that beneficial interactions can be facilitated
and detrimental interactions can be minimized.