Invasive Seaweeds
and the Last Frontier, Alaska
Mandy Lindeberg
November 1, 2010
Wireweed, Sargassum muticum
Auke Bay Laboratories
Alaska Fisheries Science Center
Overview: Invasive Seaweeds and Alaska
• Invasive seaweeds defined
• Global statistics
• Profiling some notorious invaders
• Alaska, the last Frontier for invaders
• Management of Invasive, weedy species
Seaweeds: what they are and are not!
Seaweeds are:
• macro-algae or benthic marine algae.
Red seaweeds
Seaweeds are not:
• Microalgae – unicellular and microscopic
(dinoflagellates and diatoms).
• toxic algae blooms, red tides, ciguatera,
etc.
ciguatera
Red Tide
Sea“weeds”: good, bad, and ugly
Defined
• Good – native or endemic seaweeds.
• Bad - some seaweeds don’t belong :
non-native, exotics, aliens,
introduced, etc.
AK Dragon Kelp
(may or may not be ecologically significant)
• Ugly - some seaweeds are “weedy”
and can become invasive (don’t have
to be aliens). Eutrification by nitrates.
Wakame
Native Sea Lettuce bloom
Global Seaweed Invasions: the numbers
#1 Hot Spot – Mediterranean Sea
• 85 introduced seaweeds
• 9 are considered invasive
• Thau Lagoon, southern France
has 45 introduced species or
23% of flora
Other Regions: (introduced species)
• US eastern Atlantic coast - 28 species
• New Zealand – 21 species
• Hawaii – 18 species
• California – 12 (2%)
• San Francisco Bay is CA hot spot.
• Alaska – 3 species
Global Invasions: Mechanisms of transport
Nearly all due to human activity:
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Tanker ballast water; on hulls
Shellfish farming
Seaweed mariculture
Aquarium trade
Packing for live seafood
Hosts for invasive invertebrates
Global Invasions: Seaweed allstars
Global Invasive Species Program
• 2 seaweeds have made the top
100 most invasive species list:
“Killer Seaweed” and Wakame
Impressive statistics:
• Killer Seaweed invaded the Mediterranean
at a rate of 50 km/yr and displaced 30,000
acres of seagrass meadows.
• 500,000 wet tons/yr of Wakame are
harvested from Asian Pacific. Intentionally
introduced for mariculture in Europe.
Killer Seaweed: Caulerpa taxifolia hybrids
Profile
Habit: green seaweed, SP-P, 1-50m depth, any
substrate, fast growing, spreads by
fragmentation, tropical to temperate waters.
Native Distribution: Australia
Transport Mechanism: hybirdizing with
aquarium strains.
Non-native Distribution: (1984)
Mediterranean Sea, (2000) California, southern
Australia.
Invasive Impacts: can displace native
seaweeds and seagrass meadows, distasteful
to herbivores, smothering of native fauna.
Management: aggressive techniques such as
plasitc sheets and poisoning with chlorine;
Legislation banning sale; successful eradication
in CA but cost $7 million over 6 yrs.
Caulerpa taxifolia
(M. Vahl) C. Agardh
Asian Kelp or Wakame: Undaria pinnatifida
Profile
Habit: annual kelp, SE-P, low intertidal to
5m depth, subtidal rocky shorelines, fast
growing to ~2m; 10-20C.
Native Distribution: Japan, Korea, China
Transport Mechanism: Oyster farming,
vessels.
Non-native Distribution: Australia, New
Zealand, Mediterranean Sea, France,
Argentina, Mexico, (2000) California – San
Diego to SF Bay.
Invasive Impacts: can displace native kelp
species including canopy species, fouling
fishing gear and other marine structures.
Management: aggressive; manual removal
on scuba; commercially grown and
harvested.
Undaria pinnatifida
(Harvey) Suringar
Alaska… the Last Frontier
A paradox for invasive seaweeds
Advantages
Disadvantages
• Huge coastal area, easily go
undetected.
• Regional differences may limit
expansion.
• Many routs: vessels, currents
• Transport too far to survive.
• Warming waters
• Still cold, glacial runoff
• Native species may not be able • Many AK species well adapted
to compete.
to extreme conditions.
Alaska’s Seaweeds:
Status of our Seaweeds
• There are 3 known aliens already here:
(not considered invasive)
• Ceramium kondoi
• Porphyra purpurea
• Sargassum muticum
• We still don’t have a comprehensive
baseline; still discovering new or
undescribed species.
Range extension - Giant Kelp
Macrocystis pyrifera
• We are witnessing range extensions
possibly due to climate change.
• Unique species that are cold water
adapted have a high risk of extinction
(Golden V Kelp). Island effect.
AK endemic - Golden V Kelp:
Aureophycus aleuticus
Wireweed: Sargassum muticum
Profile
Habit: brown perennial, E-P, rocky
substrate, highly tolerant to desiccation,
salinity, and temp., fast growth to 16m
long and forms floating mats, drifting
fronds reproductive.
Native Distribution: Japan
Transport Mechanism: oyster farming.
Non-native Distribution: (1944) western
North America – AK to Mexico, (1966)
Europe – Norway to Italy .
Invasive Impacts: WA State- it reduces
density and species richness of native
canopy seaweeds but not richness of
understory.
Management: manual removal;
none successful.
AK native species:
Cystoseira geminata
C. Agardh
Invasive species:
Sargassum muticum
(Yendo) Fensholt
Dead Man’s Fingers: Codium fragile
Profile
Habit: green annual growing to 3 ft, SE-P, intertidal
and shallow subtidal on rocky shorelines, weedy with
reproduction by fragmentation; 54-59 F (tolerates
28F); salinities 17.5-40 ppt.
Native Distribution: Japan
Transport Mechanism: oyster farming, vessels,
packing material.
Non-native Distribution: (1900) Netherlands, North
Atlantic, New Zealand, Australia, California – SF Bay
(1977).
Codium fragile subsp.
tomentosoides
(van Goor) P.C. Silva
Invasive Impacts: displaces native species; overgrows
and dislodges shellfish in New England (“oyster
thief”); can form rotting piles with foul odor.
Management: New Zealand has a native sea slug that
keeps it in check; eradication efforts had no effect.
AK native Species
Codium fragile subsp. californicum
(J.Agardh) Maggs & J.Kelly
Drawf form of Rockweed
Profile
Habit: brown perennial, very high
intertidal mixed in with salt marsh
vegetation, SP-P, rarely reproductive.
Native Distribution: Northeast Atlantic,
Pacfic Coast of North America.
Fucus distichus subsp. evanescens
(C.Agardh) H.T. Powell
Non-dwarf form of Rockweed
The Blob in Alaska!
Locals/ Responders Perplexed
• First responders treated it like an
oil spill.
• Locals worried about toxic
impacts.
• Where are the experts?
Reality check
• Educate responders and
locals.
• Get samples to right folks.
• Why did it happen?
Secondary symptom of
climate change?
July 18, 2009
Dwarf Eelgrass: Zostera japonica
Profile
Habit: seagrass 4-14” long and 1.5mm
wide, annual or short-lived perennial, SPP, mid intertidal, sandy and muddy
shores, salt or brackish waters; 6-7 month
life cycle.
Zostera japonica
Aschers. & Graebn.
Native Dist.: Asia, Russia, Sakhalin Is.
Transport Mechanism: packing with
oysters.
Z. japonica
Non-native Dist.: (1957) North America –
BC, WA, OR.
Invasive Impacts: colonization of bare
intertidal flats drastically modifying
habitat. Creates habitat for migratory
birds!
Management: control methods not
investigated.
Z. marina
Dwarf Eelgrass
Chord Grass: Spartina spp.
Profile
Habit: perennial grass, 1-1.5m tall, SP-P,
on mud flats, estuaries, salt marshes,
sand or cobble beaches.
Native Dist.: Atlantic Ocean
Transport Mechanism: introduced for
dike stabilization, cattle feed, oyster
farming.
Non-native Dist.: last 200 years globally;
(1960s) Pacific Northwest .
Invasive Impacts: aggressively displaces
native vegetation, alters ecosystem.
Management: manual removal,
introduction of herbivorous insect,
regulated herbicides; not successful.
clones, Willapa Bay,
WA
Spartina spp.
Management Plans for Invasive Seaweeds
Largely ignored, wetland plants get more attention
There are few success stories when seaweeds invade, but:
• CA, aggressive including legislation.
• Maine – Dead Man’s Fingers
• Hawaii
Hawaiian Islands
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networked
public education
information accessible
multi-agency funding
The Aquatic Invasive Species
Response Team (AIS Team) Hawaii
Mgmt Plan.
Hawaii’s Attack:
Super Sucker!
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underwater vacuum, runs on bio-fuel.
can remove 800 lbs/hr.
Modified gold dredge.
2006: 50,000 tons removed from reefs
targets aliens Gracilaria and Eucheuma (invades 300m/yr.).
recovered seaweed is used as fertilizer for farmers.
Other techniques:
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transplanting urchins
transplant native seaweeds
herbivorous fish replenishment zones
community based volunteer clean-ups.
Public education via web
Internet guides to ID invasive
species.
Alaska’s Plan for Invasive Seaweeds?
Well on our way with workgroup
• Need AK Invasive Species Council
• Web Resources:
• USDA Invasive Species Info for AK
• Aquatic Nuisance Species Task Force.
• AK Spartina Prevention, Detection and
Response Plan, NMFS.
• Seaweeds of Alaska.com?
• Expand our knowledge of invasive
species to all regions of AK.
Thank You
New!
A Field Guide to Seaweeds of Alaska
By Mandy Lindeberg and Sandra C. Lindstrom
More than 100 of the most common
seaweed species in Alaska’s waters,
as well as seagrasses and marine
lichens, are fully described and
illustrated with color photos on
water-resistant paper.
Come see at poster session!
For more information visit:
Seagrant.uaf.edu/bookstore
Seaweedsofalaska.com