Alewife: Assessment and Impacts on Lake
Champlain
(Brooks and Dodson,
1965)
Marty Frye, Lecia Babeu, Will Matukonis, Zack Clark
Goal/Purpose Statement
We seek to understand the
impacts of alewives on:
• Trophic interactions
• Species populations
• Aquatic ecosystem balance
In Lake Champlain
OBJECTIVES
• Select specific endpoints for assessing
alewife impacts on natural systems in
Lake Champlain.
• Examine the effects of alewife on:
o
o
o
Other fish specie’s eggs and larvae
Salmonid populations (Early Mortality Syndrome)
Zooplankton and Phytoplankton
Who's da Fish with da Funny Name?
-Alosa
pseudoharengus
-Anadramous fish of the herring family
native to the Atlantic coast north from the
Carolinas
-Planktivorous, focusing on larger
zooplankton.
Also eat the larvae of other fish
-Preyed upon by most larger piscivorous
fish
-A "brittle" species
-doesn't do well with dramatic
temperature changes
-not easily transported by humans
(Bean 2002) (USGS 2010)
Ecology and Life History (in Land
locked Lakes)
- Generalists. Highly invasive.
- Out-compete other fish and over-feed on macrozooplankton.
- Can become a huge part of the diet of larger fish.
- Don't like the super-cold.
- Retreat to deeper water during winter.
- Move towards shallow waters in April.
- Spawning peaks in July
Disclaimer: Alewife is a native and culturally valued fish along
the Atlantic coast and connected river-ways and there
are efforts to restore impaired populations in these areas.
(Bean 2002) (Madenjian et al 2008)
Introduction and Invasion in Other
Lakes
- First detected in Lake Ontario in 1873. Established in
all Great Lakes by 1954.
- Modes of Introduction:
- Natural movement between water bodies
- Human stocking
- Movement through human-built waterways
- Recorded in Lake St. Catherine in 1997
(Bean 2002) (Good and Cargnelli 2004)
(USGS 2010)
Good and Cargnelli 2004
Alewife in Lake Champlain
- First observed in 2003
- Exhibited a population boom and a winter mass die-off in
2007-2008.
- Monitoring and assessment underway
- No conclusive alewife impacts on the lake yet
- No management plan established
(Vermont Agency of Natural Resources 2008)
Findings
http://www.maine.gov/dmr/searunfish
/alewife/index.htm
Case Study - Otsego Lake, NY
• Introduced in 1986, established population
• Shallower than Lake Champlain, biologically similar
(Harman, 2006)
In 1990s Otsego Lake exhibited increases in:
• Oxygen depletion rates
• Chlorophyll a
• Phosphorus
• Decrease in transparency
Introduced fish species studied since 1930s, lots of pre-alewife
data
(Albright et al., 2002)
Following Introduction
Water turned green with algae
o Lack of large algal grazing zooplankton
o Large zooplankton population reduced by
alewife
Increased algal blooms increased turbidity
o Reduced Secchi depth measurements
(Harman, 2006)
lakechamplaincommittee.org
co.carver.mn.us
Secchi disk transparency in Otsego Lake prior to alewife
introduction, and post alewife introduction (Harman, 2006).
Zooplankton Size Distribution
Introduction changes size distribution
o Alewife prey selectively on large zooplankton
o Zooplankton size distribution useful indicator of ecological
impacts of alewife
(Kraft, 2006)
In Otsego Lake ciscoes dominated from 1970-1988
o Large bodied zooplankton dominated
o Grazing on algae, low algal biomass
o Alewife become more abundant
hamiltonnature.org
o High transparency, deeper Secchi depth
(Albright et al., 2002)
Size Distribution Cont.
Post introduction shift in zooplankton community cf.adfg.state.ak.us
Alewife selectively prey on large zooplankton
 Daphnia and Leptodora
Since 1990s
 Bosmina coregoni
smaller zooplankton species has dominated Otsego Lake
(Albright et al, 2002)
Alewife have top down effect on food web
o Establishment -- fewer large cladoceran, especially
daphnia
o Increased populations of small cladocerans and
copepods
o Increased algal biomass, lack of large cladocerans
consuming large algal particles
(Kraft, 2006)
(Brooks and Dodson, 1965)
Landlocked vs. Anadromous Alewife
• Both prey on zooplankton
o Landlocked, continuous interaction with zooplankton
• Keystone species in some E. North American lakes
o Dominant in determining structure of zooplankton
communities
• Lakes with landlocked alewife
o Smaller bodied zooplankton
o After introduction, rapid decline in zooplankton body size
o Constant predation pressure on zooplankton
o Zooplankton size remains small throughout growing season
o Changes in zooplankton community drive natural selection
of next generation
o Eco-evolutionary feedbacks strong
(Palkovacs and Post, 2008)
Eco-evolutionary Feedbacks
Strong in landlocked populations
• Landlocked alewives become morphologically adapted
to foraging on smaller prey
• Consume smaller prey/zooplankton
• Shift in body size of zooplankton present after
introduction
• More pronounced for cladocerans than copepods
(Palkovacs and Post, 2008)
fmel.ifas.ufl.edu
(Palkovacs and Post, 2008)
• Condition prevalent in species that prey upon alewife.
(Lake Trout, Atlantic Salmon)
Lake Champlain: The extent to which alewife contribute to thiamine
deficiency in fish species in unknown, however thiamine deficiencies
have been recorded in Lake Trout, this is probably true for other species
as well.
(Marsden 2010)
An enzyme present in certain plant/fish species that
splits Thiamine molecules in two.
Thiamine
http://arginine.chem.cornell.edu/Structures/Thi-I.html
A vitamin of the B-complex, essential to animals.
http://www.answers.com/topic/thiaminase
Family Cyprinidae (Minnows or carps):
Common bream (Abramis brama)
Central stoneroller (Campostoma anomalum)
Goldfish (Carassius auratus)
Common carp (Cyprinus carpio)
Emerald shiner (Notropis atherinoides)
Spottail shiner (Notropis hudsonius)
Rosy red, Fathead minnow (Pimephales promelas)
Olive barb (Puntius sarana)
Family Salmonidae (Salmonids):
Lake whitefish (Coregonus clupeaformis)
Round whitefish (Prosopium cylindraceum)
Family Catostomidae (Suckers):
White sucker (Catostomus commersonii)
Bigmouth buffalo (Ictiobus cyprinellus)
Family Ictaluridae (North American freshwater catfishes):
Brown bullhead catfish (Ameiurus nebulosus)
Channel catfish (Ictalurus punctatus)
Other families:
Bowfin (Amia calva) - family Amiidae (Bowfins)
Burbot (Lota lota) - family Lotidae (Hakes and burbots)
White bass (Morone chrysops) - family Moronidae (Temperate basses)
Rainbow smelt (Osmerus mordax) - family Osmeridae (Smelts)
Loach, Weatherfish (Misgurnus sp.) - family Cobitidae (Loaches)
http://www.wetwebmedia.com/ca/volume_6/volume_6_1/thiaminase.htm
Characterized by:
-Loss of Equilibrium
-Lethargy
-Hemorrhaging
-Hyperexcitability
-Ultimately, death.
-Effects of EMS found in Atlantic Salmon, Steelhead
Trout, and Lake Trout in the Great Lakes. (Mandenjian, 2008)
“The proliferation of alewives in the late 1870’s appears to have been the
keystone change in the great lakes ecosystem that pushed the Atlantic
Salmon population to extirpation via EMS reducing fry survival and
perhaps also via anorexia, induced by thiamine deficiency, causing
starvation of adults.” (Ketola et al., 2000)
Heavily Impacted Fish Species
*NOT AT ALL TO "SCALE"*
pond.dnr.cornell.edu
Atlantic Salmon
• Early life stages of atlantic salmon are not at risk of predation
by alewife because they do not overlap spatially.
o
Atlantic salmon spawn in up-stream reaches where they spend up to
two years. (Ketola,2000)
• Threat to Atlantic Salmon is mainly Early Mortality Syndrome
• Lag time in negative effects on salmon populations
o
EMS chokes recruitment rates (Madenjian, 2008)
• Lake Ontario Example
o
Strong correlation between alewife invasion and atlantic salmon
extirpation. (Madenjian, 2008)
Lake Trout
• The early life history of lake trout allows larvae to
be vulnerable to predation by alewife.
o
o
Spatial Overlap!
Pelagic lake trout eggs typically hatch during April and May
(Madenjian, 2008)
• Tank experiments have shown that the predator
avoidance response shown by lake trout larvae
is to flee upward in the water column
o
Creates spatial overlap and leaves lake trout larvae very
susceptible to predation by alewives
(Strakosh and Krueger 2005)
sciencenews.org
Lake Trout
• Several other compounding factors which
contribute to Lake Trout population declines
o
o
o
Overfishing
Predation by sea lamprey
EMS
• Important to differentiate between lake trout
population declines induced
by different factors.
o
Which declines are more
heavily alewife related?
sportfishingamericas.files.wordpress.com
Lake Trout
• Lake trout stocks collapsed in all five Laurentian
Great Lakes by 1960, primarily through overfishing
and predation by sea lampreys. (Hansen, 1999)
• Regardless of lake trout stocking programs begun in
the 1960s and 1970s, only lake trout populations in
Lake Superior have recovered.
**highly correlated with a very low abundance of alewife**
(Madenjian, 2008)
• Remember: Even with successful recruitment, lake
trout face a double threat from alewife - EMS and
predation
Emerald Shiner
• Due to its physical and ecological similarity to alewife, it is
particularly at risk to alewife invasions.
o
OVERLAP!
• Alewife interfere with emerald shiner reproduction by
feeding on pelagic eggs and fry
o
o
Peak hatching of emerald shiner eggs occurs in June and July
Eggs and larvae are pelagic, and newly hatched larvae have been
observed primarily in shallow water (Madenjian, 2008)
• This life cycle overlaps spatially
and chronologically with alewife
reproductive cycles and puts the
emerald shiner at high risk of
predation.
Emerald Shiner in the Great Lakes
• Studies in the great lakes have shown a high correlation
between alewife population increases and emerald shiner
population crashes.
• Studies in Lakes Michigan and Huron have shown that
Emerald Shiner populations were greatly reduced during
the early 1960s
o
Coincident with the increased abundance of alewives in both lakes
(Madenjian, 2008)
• The emerald shiner population collapse in Lake Michigan
spread from the northern part of the lake southward
o
Spatially coincident with the spread of alewives into the lake
(Wells, 1977)
• Emerald shiner populations in Lakes Michigan, Huron, and
Ontario have not recovered since 1960
o
Largely due to a lack in alewife population declines (Wells, 1977)
These aren't the only impacted fish
species....
•
•
•
•
•
Slimy sculpin
Lake whitefish • Yellow
Cisco
perch
Bloater
Rainbow smelt
Minimal Effect
image: csulb.edu
• Atlantic salmon
• Deepwater
• Lake trout
sculpin
• Emerald shiner
Strongest
Effect
Chart Recreated from Madenjian, 2008
Social Implications
• Die-offs reek and are unsightly
• Lost cultural heritage attached to native
fish being displaced
• Reduced recreation/use of lake with more
die-offs
• May increase algal blooms
bobberbobsfishen.com
Economic Implications
• Reduced lake trout and salmon viability
makes for bad fishing.
• Tourism hurts: mass die-offs, fishing,
stigma of having a non-pristine lake
dominated by invasives
• Algal blooms lead to decreased use of
lake for many activities
bizbox.slate.com/blog/dollar-sign.jpg
Ecological Implications
...a take home message
• Prey fish species are largely displaced
o Shifting trophic interactions
• Larger zooplankton are selectively preyed upon
o Small zooplankton and phytoplankton proliferate.
• Large fish subject to EMS
are less viable
• Die-offs don't seem to have
major ecological impacts.
www.studentforce.org.uk/toolkit
Assessment Endpoints
•
•
•
•
•
•
Secchi depth measuring turbidity
Zooplankton species populations
Phytoplankton species populations/abundance
Population of at-risk fish species
Salmonid egg hatching success (EMS effects)
Direct testing for thiamine deficiency in salmonids
seagrant.wisc.edu
http://www.paranormalencyclopedia.com/c/champ/
Recommendations
ActionPreventative Measures• Strict measures restricting • Increase stocking of lake trout
transportation of alewife in- and atlantic salmon following
die-offs
state are already in place.
• Increase monitoring
o zooplankton size distribution
and populations
• More research on diet of
alewife and ecological niche in
Lake Champlain
• Assess effectiveness of
monitoring
... or dead ones.
Literature Cited
Albright., M.F., Harman, W.N, & Warner, D.M. (2002). Trophic changes in Otsego Lake, NY following the introduction of the
alewife (Alosa psuedoharengus). Lake and Reservoir Management, 18(3), 215-226.
Bean, Tim. (2002) “Introduced Species Summary Project: Alewife: /Alosa pseudoherengus/.” Retrieved from
http://www.columbia.edu/itc/cerc/danoff-burg/invasion_bio/inv_spp_summ/alewife.html.
Brooks, J. L. & Dodson, S. I. (1965). Predation, body size, and composition of plankton. Science, 150, 28-35.
Flittner, G. A. (1964). Morphometry and life history of the emerald shiner, Notropis atherinoides Rafinesque. Doctoral
dissertation.University of Michigan, Ann Arbor.Hansen, M. J. (1999). Lake trout in the Great Lakes: basin wide stock collapse
and binational restoration. Michigan State University Press. 417-453.
Good, S and Cargnelli, L. (2004) "Alternative Strategies for the Management of Non-Indigenous Alewives in Lake St.
Catherine, Vermont." Retrieved from _http://www.vtfishandwildlife.com/library/
Reports_and_Documents/Fish_and_Wildlife/Alewife_Final_Report_-_April_2004.pdf_.
Ketola, G. H., Bowser, P.R., Wooster, G.A., Wedge, L.R., & Hurst, S.S. (2000). Effects of thiamine on reproduction of Atlantic
salmon and a new hypothesis for their extirpation in Lake Ontario.
Transactions of the American Fisheries Society, 129:607–612.
Lake Champlain Alewife Impacts – February 2006 Workshop Summary (3 Speakers)
Harman, W. N. (2006, February). Trophic Changes Following the Introduction of the Alewife in Otsego Lake, NY. Lecture
presented at Burlington, VT.
Kraft, C. E. (2006, February). Food Web Effects and Population Dynamics of Alewives, Lecture presented at Burlington, VT.
Madenjian, C.P. (2008). Adverses Effects of Alewives on Laurentian Great Lakes Fish Communities. North American Journal
of Fisheries Management, 28(1):263-282.
Palkovacs, E.P., and Post, D.M. (2008). Eco-evolutionary interactions between predators and prey: can predator-induced
changes to prey communities feed back to shape predtor foraging traits? Evolutionary Ecology Research, 10:699-720.
Post, D.M., Palkovacs, E.G., Schielke, E.G., & Dodson, S.I. (2008). Intraspecific phenotypic variation in a predator
affects zooplankton community structure and cascading trophic interactions. Ecology, 89:2019-2032.
Strakosh, T. R., and Krueger, C.C. (2005). Behavior of postemergent lake trout fry in the presence of the alewife, a
nonnative predator. Journal of Great Lakes Research, 31:296–305.
USGS. (2010). “Non-Indigenous Aquatic Species.” Retrieved from http://nas.er.usgs.gov/queries/
speciesmap.aspx?SpeciesID=490.
Vermont Agency of Natural Resources. (2008). "Lake Champlain Sees Its First Alewife Die-Off." Retrieved from
_http://www.vermont.gov/portal/government/article.php?news=201_.
Wells, L. (1977). Changes in yellow perch (Perca flavescens) populations of Lake Michigan, 1954–75.Journal of the
Fisheries Research Board of Canada, 34:1821-1829.