Robert Mauk- Texas Parks and Wildlife Dept.

Robert.Mauk@tpwd.texas.gov, 940-766-2383

Aquatic Invasive

Species

What is an Aquatic Invasive Species?Aquatic invasive species (AIS) are

nonindigenous species that threaten the

diversity or abundance of native species, the

ecological stability of infested waters, and/or

any commercial, agricultural, aquacultural, or

recreational activities dependent on such

waters.

Nonindigenous Aquatic Nuisance Prevention and Control

Act of 1990 (Dec 29, 2000; PDF | 259 KB)

Aquatic Invasive AnimalsAsian Carps

Bighead Carp (Hypophthalmichthys nobilis)

Black Carp (Mylopharyngodon piceus)

Grass Carp (Ctenopharyngodon idella)

Silver Carp (Hypophthalmichthys molitrix)

Asian Clam (Corbicula fluminea)

Northern Snakehead (Channa argus)

Nutria (Myocastor coypus)

Quagga Mussel (Dreissena rostriformis bugensis)

Rusty Crayfish (Orconectes rusticus)

Spiny Water Flea (Bythotrephes longimanus)

Zebra Mussels (Dreissena polymorpha)

Zebra Mussel InvasionNative to Eurasia – Black & Caspian Sea drainages

Invaded North America by 1988 (Lake St. Clair, Canada)

Invasion pathway - ocean-going vessels

North American ZM Distribution

Texas ZM Distribution

Zebra Mussel IdentificationSmall mussel with varying stripes and flat keel

Attaches to surfaces with byssal threads

Keel

Life Cycle-(generalized)Reproduce via ‘Broadcast Spawning’:Broadcast Spawning- the female mussel releases her egg in the water to be met by the male sperm. They fuse to form gametes.

Life-Cycle Characteristics/Success-• Sexually mature in 1st year• Female may release up to 1 million eggs• Egg release is dependent on water temp.• Must be above 12 degrees C• Optimal temperature- 28 degrees C

Biology• Larvae are microscopic and free floating• Juveniles settle, attach to hard surfaces• Filter up to 1 L/day• Can grow 0.5 mm/day (to 2.0 cm/year); Max. shell size is 3.5 –

4.0 cm• Life Span: 1.5 - 2 years*• Densities ≥ 700,000/m2 have been reported• Tolerate a wide range of conditions• Survive out of water for days even weeks

Biology

Physical

ParameterUnsuitable Marginal Suitable

Average August

Water

Temperature

>32°C 31-32°C <31°C

pH <6.8 or >9.5 6.8-7.4 7.4-9.5

Calcium Ion

Concentration<12 mg L-1 12-28 mg L-1 >28 mg L-1

Dissolved

Oxygen

as % of Air O2

Saturation

<30% O2 30-50% O2 >50% O2

Risk assessment parameters - zebra mussel

invasion of TX and other SW US waters.

Chart courtesy of Dr. Bob McMahon, UT-A (article in press)

Zebra Mussel Risk Factors:Overland Transport

Next 30 days

Previous 30 days

Source: 2014 TX Boater Surveys

Economic Impacts• Cleaning intake structures and pipelines• Increased pumping expenses• Increased maintenance and repairs• Retrofitting costs ~$1.8M

Ecological Impacts• Decrease plankton/productivity• Increase water clarity; increase vegetation• Alter food web / fish community• Biomagnify pollutants, create “dead zones”• Smother native mussels

Recreational ImpactsFoul boat hulls/motors; plug water intake systems

Colonize hard structures (docks, piers, buoys, bridges, etc.) and beaches

Methods of DispersalBarges, boats, recreational equipment

Downstream flows

Water transfers

Fish / animals (birds unlikely)

Jerry Holt, MN Star Tribune, 2014

Management EffortsSpot treatments – not eradicationManage economic impacts

Rod Aydelotte, Waco Tribune, 2014

Possession of Prohibited Species IllegalPossession of Zebra Mussels or other Prohibited Species is Illegal—live or dead

It is an offense for any person to release into the water of this state, import, sell, purchase, transport, propagate, or possess any species, hybrid of a species, subspecies, eggs, seeds, or any part of any species defined as a harmful or potentially harmful exotic fish, shellfish, or aquatic plant.

See the TPWD website or Title 31 Ch 57A, Texas Administrative Code for a full list:

http://tpwd.texas.gov/huntwild/wild/species/exotic/prohibited_aquatic.phtml

All Water Must Be Drained From BoatsExcept as otherwise provided, no person may use any public roadway to transport a vessel to or from a public water body unless all bilges, live wells, and other similar receptacles and systems holding or capable of holding water on board the vessel have been drained. This regulation is applicable statewide.

Noteworthy exceptions: travel between points on the same lake, same day; tournament participants; emergency responders

Regulations regarding ‘Draining of Water from Vessels Leaving or Approaching Public Fresh Water’ (Title 31 Ch 57 Texas Administrative Code, Rule 57.1001)

Prevention: Public Awareness Campaign

Plankton sampling (veliger larvae)Twice per year – May/June, Oct/NovWater temperatures ~ 64 - 77˚F (18 - 25 ˚C)

AnalysisVeliger larvae - Microscopy (CPLM / LM)DNA - PCR

Monitoring: Early Detection & Population Dynamics

Coordinated Monitoring EffortsSettlement Samplers (juveniles/adults)

‘Rock Kick’ Substrate Surveys (juveniles/adults)

58+ Water bodies, numerous partners

Clean, Drain, and Dry• Assume boat is infested• Remove any organic matter• High pressure wash•Hull, lines, bumpers, motor, trim tabs,

anchor trailer,and all nooks and crannies

•>140 degrees F

• Drain and flush any water•Bilge, live wells, bait buckets, cooling system

ResourcesTPWD Zebra Mussel Map: TPWD site > Water > Invasive Species (look for “see map” link)Zebra Mussel “News Roundup” (search on internet or TPWD site)Outreach Materials: www.TexasInvasives.org > Get Involved > Spread The Word

Aquatic Invasive Plants

Aquatic Invasive PlantsAlligatorweed (Alternanthera philoxeroides)

Curly Pondweed (Potamogeton crispus)

Eurasian Watermilfoil (Myriophyllum spicatum)

Giant Reed (Arundo donax)

Giant Salvinia (Salvinia molesta)

Hydrilla (Hydrilla verticillata)

Water Hyacinth (Eichhornia crassipes)

Water Lettuce (Pistia stratiotes)

Water Spinach (Ipomoea aquatica)

Treatment Proposal

Aquatic Vegetation Management In Texas:

“A Guidance Document”

www.tpwd.state.tx.us/publications/pwdpubs/media/pwd_pl_t3200_1066_1.pdf

* Required prior to any treatment on public water

Containment

Herbicide Control Efforts

Physical/ Mechanical Removal

Biocontrol Integrated pest management is the strategic use of

one or more techniques to control nuisance aquatic

species at the most cost-effective level without

hurting anyone or negatively impact the ecology of

the aquatic environment.

Outreach

Giant Salvinia in Texas• First discovered in Texas in 1998 – private water• Toledo Bend – 1st public water body established

Numerous treatment methodologies used• Herbicides• Weevils• Harvesters• Booms/Fence • Blow torch!!!

SALVINIA DID NOT DIE!

Areas at RiskDark blue - Salvinia eradicated

Red – Salvinia present

Light blue - Salvinia recently

established

Green - Salvinia threat due to

proximity to infested lakes

Where to lookSlow, quiet backwaters

Shallow water but not necessary

Lots of other vegetation

Lots of nutrients, esp. Nitrogen

Giant Salvinia Control10,790 Acres treated in FY1621,984 Acres Treated in FY17

Status at beginning of FY17• 17 lakes infested • 8 lakes eradicated

New infestations in FY17• 4 lakes infested

Eradications in FY17• 2 lakes eradicated

Herbicide Cost/AcreRapid Response Treatments

$56.80 - $121.62/AcreRequires multiple treatments

Established Treatments$25.65 - $76.22/AcreRequires multiple treatments

BiocontrolGiant Salvinia Weevils FY16• 583,200 adults releasedGiant Salvinia Weevils FY17• 284,422 adults released

Water Hyacinth ControlCurrent Status• 58 lakes present (red)• 10 lakes eradicated (green)

1,702 Acres Treated in FY162,157 Acres Treated in FY17 #

###

### #

##

#

####

##

###

##

#

#####

##

#

##

##

#

#

#

####

#

# #

#

####

######

#

##

#

#

#

#

###

#

County OutlineState Boundary

Waterhyacinth locations.shp

# Eradicated

# Present

N

Floating Heart spp.

Yellow Floating Heart Crested Floating Heart

Thanks! Questions?

Visit our new web pages for updates:

http://tpwd.texas.gov/landwater/water/aquatic-invasives/

Monica McGarrity - Austin AIS Team Leader

monica.mcgarrity@tpwd.texas.gov, 512-552-3465