Download Invasive Fishes of the Colorado River basin

The Colorado River basin, its Native
and Non-native Fishes, and the
Potential for Application of Genetic
Biocontrol to the Conservation of an
Imperiled Fauna
Paul C. Marsh
Marsh & Associates, LLC
Historical Setting
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Isolated for millennia
Depauperate ichthyofauna
Six freshwater families; 53 +/- taxa
48 of 53 (91%) of these taxa are endemic
Three marine/estuarine families, 3 species
56 +/- total taxa
Native Freshwater Families
Salmonidae: 4 taxa
Cyprinidae: 27 taxa
Catostomidae: 9 taxa
Native Freshwater Families
Cyprinodontidae: 10 taxa
Poeciliidae: 1 taxon
Cottidae: 2 taxa
Native Marine/Estuarine Fishes
Elopidae
Mugilidae
Eleotridae
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How Did We Get Here?
• Physical changes
• Socio-politics and economics
• Non-natives
Regional drought, livestock grazing, logging, road building
dam building and
impoundment
channelization
Sociopolitical & Economic Factors
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Absence of protections until the late 1960s
Lack of interest
Failed management of native fishes
Aggressive development and promotion of
sport fisheries
• Lack of cooperation at state and federal levels
(e.g., RIP, MSCP)
Non-native Biota
Non-native Fishes in the
Colorado River Basin
• 24 families
• About 100 species
• Origins
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eastern North America
Mexico & Central America
Atlantic and Pacific oceans
Africa
Asia
Families of Non-native Fishes
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Acipenseridae
Anguillidae
Clupeidae
Salmonidae
Osmeridae
Esocidae
Characidae
Cyprinidae
Catostomidae
Ictaluridae
Clariidae
Loricariidae
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Rivulidae
Fundulidae
Goodeidae
Poeciliidae
Cichlidae
Atherinopsidae
Centrarchidae
Moronidae
Haemulidae
Sciaenidae
Percidae
Cottidae
Non-native Fishes
• The single most significant obstacle to the
successful recovery of native fishes
• The IUCN “Invasive Species Specialist Group”
lists 100 of the world’s worst invasive alien
species, and the list includes eight fishes. Six
of those eight are established (all intentionally
introduced) in the Colorado River basin, and
another has been recorded but apparently
never took hold.
IUCN “100 Worst” List Fishes
• While the underlying causes of invasive species
threats are significant and global in nature, the
threat can effectively be dealt with at the local site
level, especially through prevention, early detection
and rapid response (www.issg.org/about_is.htm).
• Prevention does not exist, detection often is
serendipitous, and response rarely is rapid, if at all.
Two Colorado River Basin Examples
• Green sunfish Lepomis cyanellus
• Western mosquitofish Gambusia affinis
Green sunfish Lepomis cyanellus
Western mosquitofish Gambusia affinis
Pluses of Genetic Biocontrol in the
Colorado River System
• Selective for the target species
• If species-specific, would not threaten non-target
species including sport fishes
• No secondary or collateral damage to the system or
its biotic components
• Could treat entire watersheds, might not require
emplacement of barriers
• Potentially less expensive to implement
• Eliminates piscicide-related issues such as
registration, human health effects, etc.
Potential Issues – Nothing New
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Containment
Unintended effects on non-target species
Effectiveness limited in time and/or space
Does not ensure or alleviate issues of project support by
agencies or the public
• Does not mitigate the conflict between sport fishes and
native fishes
• Addition of genetically-modified organisms to a water
body could temporarily increase impacts to natives
• Public distrust of genetic manipulation could result in
lack of support or outright opposition
The Bottom Line
Acknowledgements
Rob Clarkson (Reclamation)
Tom Dowling (Arizona State University)
Abe Karam & Brian Kesner (Native Fish Lab at M&A)
Jerry Stefferud (Forest Service, Ret.)
Sally Stefferud (Fish & Wildlife Service, Ret.)
Introductory Remarks
• Not going to hear anything not already heard, but for
a different place and different fauna
• Perhaps learn a few things about the Colorado River
system and its native fishes
• Non-native fishes are a problem in the basin, and
genetic biocontrol might be a useful tool
• Do not represent a management agency and am not
burdened with the task of issuing a “company line”
• The “take home” message is that native fishes are in
desperate need and can use all the help they can get
Geographic Setting
• SW United States (AZ, CA, CO, NM, NV, UT, WY) and
NW Mexico (BCN, Son)
• Three geographic provinces: Rocky Mountains,
Colorado Plateau, and Basin & Range
• Drains 632,000 km2 (1/12th of the continental United
States
• 2320 km long (2725 km via Green River)
• Elevations from >4,000 m to below sea level
• mouth at the Sea of Cortez (Gulf of California)
In the lower basin the river and
its tributary streams flow through
some of the hottest and driest
deserts on the continent
Historical Setting
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Isolated for millennia
Depauperate ichthyofauna
Six freshwater families; 53 +/- taxa
48 of 53 (91%) of these taxa are endemic
Three marine/estuarine families, 3 species
56 +/- total taxa
Status of the Freshwater Fauna
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3 (5%) species extinct
17 (32%) species endangered
7 (13%) species threatened
12 (23%) species state listed, special concern,
or under conservation agreement
• 39 of 53 (74%) taxa are in trouble, or gone
How Did We Get Here?
• Landscape changes wrought by regional drought and
land uses (grazing, logging, roads, housing, etc.)
• Loss of habitat or habitat suitability (desiccation,
thermal alteration, loss of habitat complexity, loss of
interconnectedness)
• Dams, impoundment & channelization
• Socio-political and economic factors
• Introduction & establishment of non-native biota
Introductions of Non-native Biota
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Fishes
Invertebrates
Parasites
Disease organisms
Plants
Non-native Fishes
• The single most significant obstacle to the
successful recovery of native fishes
• The IUCN “Invasive Species Specialist Group”
lists 100 of the world’s worst invasive alien
species, and the list includes eight fishes. Six
of those eight are established (all intentionally
introduced) in the Colorado River basin, and
another has been recorded but apparently
never took hold.
• A majority of non-native fishes are implicated
in conflicts with native species.
• Mechanisms of interaction include
– Predation & competition
– Hybridization (especially among trouts)
– Novel parasites and diseases
Green sunfish
• One of the most invasive, pervasive, and
destructive species in the basin, although not
even recognized as an invasive species by
some states
• Implicated in declines of a diversity of native fishes
including stream dwelling chubs (Gila spp.), “big
river” razorback sucker Xyrauchen texanus, and
Colorado squawfish (Ptychocheilus lucius) (Marsh &
Langhorst 1988, Tyus & Carp 1990 Dudley & Matter
2000)
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Bass & sunfish family (Centrarchidae)
Native to eastern North America
First records in the 1920s
Ubiquitous in the Colorado River basin
Small (maximum length near 35 cm)
Predaceous on native fish larvae & early juveniles of
all species, and adults of some
• Not a desired sport fish, and not intentionally
stocked or managed
• Current control technologies include chemical
treatment and mechanical removal
• Has proven difficult to eradicate, or to keep systems
free of this pest
• Is widespread and thus available to reinvade
naturally, or with help.
• Can occupy all sizes of lotic waters from tiny streams
to large rivers, and lentic waters from small ponds to
large reservoirs
• Its range continues to expand
Western mosquitofish
• Perhaps the most widespread invasive species
worldwide, and one of the most pervasive in
the Colorado River basin, especially in
warmer, southerly regions
• Implicated in declines and local extirpations of its
con-familial native Gila (Sonora) topminnow
(Poeciliopsis occidentalis) and a diversity of other
native fishes wherever the two kinds co-occur
(Minckley & Meffe 1987, many others)
• Live-bearing reproductive mode could create both
challenges and opportunities for development of an
effective biocontrol technology
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Livebearer family (Poeciliidae)
Native to southeastern United States
First records in the 1920s
Ubiquitous in the Colorado River basin
Diminutive (maximum length near 35 mm)
Predaceous on native fish larvae & early
juveniles of all species, and adults of some
• Current control technologies and issues
are similar to those for green sunfish
• Mosquitofish are stocked routinely by
counties and private parties for mosquito
control. Its range continues to expand.
• Ironically, native topminnow and desert
pupfish (Cyprinodon macularius) are
equally effective in this role, but not used
because of permitting and other issues
Existing Major Programs
UCRB-RIP. 4 listed big-river fishes, multiple partners.
Upper Colorado River basin. Goal: recovery with development
Originally 15 yrs (1988-2003), extended until 2023
Original budget $67 million, total could exceed $150 million.
60% DOI, 28% power revenues, 12% others
San Juan River RIP. 2 listed big-river fishes, multiple partners.
San Juan River mainstream. Goal: recovery with development
Originally 15 yrs (1992-2007), extended until 2023
Expended $17.8 m 2001-2009, could expend another $28 m. 79% DOI, 21% others
CAP Fund Transfer Program. Gila River basin, 4 listed stream fishes, BR/FWS+AZ/NM.
2 parts: conservation actions and non-native control.
Gila River basin. Goal: conservation with operations
25 years (1997-2022), $12.5 m budget. 100% Reclamation.
LCR MSCP. 31 species including 3 listed and 1 non-listed big-river fishes, multiple partners.
Lower Colorado River mainstream. Goal: conservation with operations
50 years (2005-2055), $626 m budget. 50% DOI, 50% states (25% CA, 12.5% AZ/NM)
• Native fish conservation and recovery in the
Colorado River basin has cost hundreds of millions of
dollars since the inception of active implementation
programs more than two decades ago
• Most target and other native fishes are inarguably in
worse shape today than when protection and
management began with the ESA nearly four
decades ago
• Traditional habitat management strategies have not
been effective because of the presence of non-native
fishes
• Control of non-native fishes is problematic
The Bottom Line
• Genetic biocontrol is an important tool that needs to
be developed and applied in the basin
• Develop alongside other novel controls such as
species-specific piscicides
• Could provide recovery opportunities where they
currently do not exist or are logistically impractical
• Could eliminate or reduce the need for current
controls such as barriers, piscicides, or mechanical
removal
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