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Order Cladocera - Waterfleas

About 70 species of waterfleas make their homes in the waters of the Great Lakes basin. Of these, only a handful make up the bulk of the open water biomass. Leptodora kindtii is a native predatory waterflea. Two recent invaders, Cercopagis pengoi and Bythotrephes longimanus are also common predatory cladocerans. Larger members of the Daphnia family are most common in the spring: Daphnia retrocurva nearshore, Daphnia galeata in the deep clear waters, and Ceriodaphnia sp. in the warm upper waters. Smaller waterfleas in the families Bosminidae and Chydoridae become more abundant in the summer and fall: Bosmina in the cool, well-oxygenated waters, Eubosmina in warm epilimnetic waters and Chydorus in the eutrophic and near-benthic waters.

The Great Lakes have 4 species of predatory waterfleas, the natives Leptodora kintii and Polyphemus pediculus, and two exotics - Cercopagis pengoi and Bythotrephes longimanus. These are raptorial predators which grasp protozoans, rotifers, and small zooplankton with their forelegs. All other native Great Lakes waterfleas are herbivores, feeding on phytoplankton, attached vegetation or decaying organic material. Most use their legs to generate a current, filter appropriate sized food particles, and pass them to the mouth. The Chydoridae and Macrothricidae have modifications to their legs which enable them to cling to vegetation and/or detritus and scrape food particles from the surfaces.

Most cladocerans can reproduce by parthenogenesis (asexual reproduction), females producing 2-20 eggs per brood that develop into young without fertilization by males. As a result, males are not present in the population for much of the year. As long as environmental conditions remain favourable females will continue to reproduce in this manner, producing only female offspring. Eggs are laid inside a brood chamber along the back of the animal and are released as free-swimming juveniles when the parent molts. If the environment starts to deteriorate due to overcrowding, lack of food, oxygen depletion. or simply seasonal changes, eggs are produced that develop into males and females capable of sexual reproduction. These females produce eggs that once fertilized by the males are capable of surviving extended periods of harsh conditions such as drying or freezing (sometimes called resting stages). Each female produces only 1-2 such eggs in a specialized brood chamber called the ephippia. When the female molts, ephippia are released - eggs remain in the ephippia until conditions trigger hatching. In this manner cladoceran populations survive through winter and periods of drought. Some zooplankton resting stages are believed to have survived centuries buried in sediment. When environmental conditions are again favourable the eggs hatch and produce parthenogenic females.

Cladocerans have hard exoskeletons and molt many times as they grow. Many species show changes in shape as they grow - characteristic of age, season, or environmental conditions.

Order Profiles and General Information -

- "Zooplankton of the Great Lakes" by Balcer, Korda and Dodson. 1984.
Globe icon indicates link to a non-NOAA site.The Cladoceran Body Plan
Globe icon indicates link to a non-NOAA site.A Key to Cladocerans (Crustacea) of British Columbia (includes most Great Lakes families except Cercopagidae)
Globe icon indicates link to a non-NOAA site.An Image-Based Key To The Zooplankton Of The Northeast (USA)
Globe icon indicates link to a non-NOAA site.The Cladoceran Life Cycle
Globe icon indicates link to a non-NOAA site.The Waterflea - An introduction to the taxonomy of the sub-fossil remains ot the Cladocera
Globe icon indicates link to a non-NOAA site.Waterfleas - Jan Parmentier & Wim van Egmond
Globe icon indicates link to a non-NOAA site.Cladocerans of the Thompson-Okanagan Region
Bird icon indicates link to a non-GLERL NOAA siteMN Sea Grant - Seiche Article - Our Lake Has Fleas

Distribution and Habitat
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Taxonomic Key
(access gallery by taxa)

Distribution and Habitat


Image Link Scientific Name Lake Superior Lake Michigan

Lake Huron

Lake Erie Lake Ontario Habitat
Family Leptodoridae            
Leptodora kindtii Leptodora kindtii x x x x x littoral and limnetic
Family Polyphemoidea            
Polyphemus pediculus Polyphemus pediculus x x x   x nearshore areas occassionally to 40m
Family Cercopagidae            
Cercopagis pengoi Cercopagis pengoi   x   x x  
Bythotrephes longiramus Bythotrephes longimanus x x x x x  
Family Sididae            
  Diaphanosoma spp.            

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Diaphanosoma brachyurum Diaphanosoma brachyurum x x x x   littoral
Diaphanosoma birgei Diaphanosoma birgei x x x x x sheltered open waters at depths of 3-6 meters
Latona setifera Latona setifera x x x x   rare
Latonopsis occidentalis Latonopsis occidentalis       x    
Sida crystallina Sida crystallina x x x x x extremely patchy distribution
Family Holopedidae            
Holopedium gibberum Holopedium gibberum x x x x x littoral and pelagic, prefers cold waters

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Family Daphnidae            
  Ceriodaphnia spp.           littoral and limnetic, usually nearshore or in the warmer upper layers of water
Ceriodaphnia lacustris Ceriodaphnia lacustris x x x x x
  Ceriodaphnia laticaudata       x  
  Ceriodaphnia pulchella x     x  
Ceriodaphnia quadrangula Ceriodaphnia quadrangula   x x x  
Ceriodaphnia reticulata Ceriodaphnia reticulata       x  
  Daphnia spp. x x x x x  
Daphnia ambigua Daphnia ambigua   x x x   very low abundances post-1970
Daphnia galeata Daphnia galeata x x x x x Deep, transparent waters.
Daphnia longiremis Daphnia longiremis   x x x x Usually found below the thermocline but above the poorly oxygenated regions
Daphnia lumholtzi Daphnia lumholtzi           Exotic.
DAphnia parvula Daphnia parvula   x       Green Bay and Milwaukee Harbor - rare

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Daphnia pulex Daphnia pulex x x x x x easily confused with Daphnia retrocurva so ID uncertain
Daphnia retrocurva Daphnia retrocurva x x x x x One of the most abundant cladocerans in the Great Lakes.
Daphnia schodleri Daphnia schodleri   x       Collected in 1970's
  Scapholeberis spp.            
  Scapholeberis aurita   x   x   Occassional, near surface, littoral.
Scapheloberis kingi Scapholeberis kingi x x   x   aka S. mucronata
  Simocephalus spp.            
Simocephalus exspinosus Simocephalus exspinosus x          
Simocephalus serrulatus Simocephalus serrulatus   x   x   Abundant in the littoral areas of Lake Erie.
Simocephalus vetulus Simocephalus vetulus x     x  
Family Moinidae            
Moina micrura Moina micrura x x       generally low numbers but may reach high densities in Green Bay
Family Bosminidae            
  Bosmina coregoni x          
  Bosmina liederi x          
Bosmina longirostris Bosmina longirostris x x x x x Found in cool, well-oxygenated waters and littoral areas. Abundant during the summer.
  Eubosmina spp.            
Eubosmina coregoni Eubosmina coregoni x x x x x prefers warm, epilimnetic water. Abundant summer species, only recently observed in the Great Lakes (post-1970).
  Eubosmina longispina (?)     x x x  

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Family Macrothricidae            
Acantholeberis curvirostris Acantholeberis curvirostris     x     shallow waters of Georgian Bay, 1903
  Drepanothrix dentata x x       rare - Isle Royale and Georgian Bay
  Ilyocryptus spp.            
  Ilyocryptus acutifrons   x       SE Lake Michigan 1980
Ilyocryptus sordidus Ilyocryptus sordidus x x   x   littoral - rare
Ilyocryptus spinifer Ilyocryptus spinifer x     x x variable abundance
  Macrothrix laticornis x x   x x rare
  Ophryoxus gracilis   x x     littoral Georgian Bay and Green Bay
  Wlassicsia kinistinensis   x       occassionally found among nearshore vegetation
Family Chydoridae            
Acroperus harpae Acroperus harpae x x   x   littoral, benthic, abundant in some areas of Green Bay
  Alona spp. x          
Alona affinis Alona affinis x x x x x benthic, near bottom in weedy littoral areas,
Alona circumfimbriata Alona circumfimbriata   x       littoral, benthic
  Alona costata x x   x   low density, littoral, benthic
Alona guttata Alona guttata x x   x   low density, littoral, benthic
  Alona lepida x         planktonic, ID uncertain
Alona quadrangularis Alona quadrangularis   x   x   littoral, benthic
  Alona rectangula x x   x   low density, littoral, benthic
  Alonella spp.            
  Alonella excisa       x   rare
  Alonella nana x     x   Isle Royale and littoral Lake Erie
  Alonopsis elongata x         rare
  Anchistropus emaginatus x          
  Anchistropus minor x x x     Isle Royale, Georgian Bay, Green Bay, weed-associated
  Camptocercus spp.            
  Camptocercus macrurus       x   near bottom in weedy areas
Camptocercus rectirostris Camptocercus rectirostris x x x x x littoral, occassional high local abundances

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  Chydorus spp. x         Nearshore and littoral - eutrophic, usually found clinging to fliamentous algae. Epibenthic by day.
  Chydorus faviformis   x      
  Chydorus gibbus x     x  
  Chydorus globosus x   x x  
  Chydorus latus       x  
Chydorus sphaericus Chydorus sphaericus x x x x x
  Disparalona spp.            
  Disparalona acutirostris x          
Disparalona rostrata Disparalona rostrata x x       recent (1980) and rare to Lake Michigan
  Eurycercus lamellatus x x x x x benthic, moving into the water column at night
Graptoleberis estudinaria Graptoleberis testudinaria   x x x   very low numbers
Kurzia latissima Kurzia latissima     x x   occassional
Leydigia acanthocercoides Leydigia acanthocercoides       x   5 sites, 1960
Leydigia leydigi Leydigia leydigi   x x x   rare
  Leydigia quadrangularis x          
Monospilus dispar Monospilus dispar x   x x   <6 per cubic meter
  Pleuroxus spp.            
  Pleuroxus aduncus       x   Cedar Bay
Pleuroxus denticulatus Pleuroxus denticulatus   x   x   littoral
  Pleuroxus hastatus x         open water 1893
  Pleuroxus procurvus   x   x    
  Pleuroxus striatus       x   4 nearshore locations
  Rhynchotalona falcata x         <1 per cubic meter

Table drawn from "Zooplankton of the Great Lakes: A Guide to the Identification and Ecology of the Common Crustacean Species" by Mary Balcer, Nancy Korda and Stanley Dodson. University of Wisconsin Press. 1984.
with additions from: Globe iconLake Superior: an invasion coldspot? 2003. Igor A. Grigorovich, Alexei V. Korniushin, Derek K. Gray, Ian C. Duggan, Robert I. Colautti& Hugh J. MacIsaac. Hydrobiologia 499: 191-210.

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