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(Cladocerans [water fleas], shrimps, copepods, amphipods [scuds], sow bugs, crayfish, fish lice)
Soil & Water Conservation Society of Metro Halifax (SWCSMH)
Family: Hyalellidae; View: lateral
Updated: October 09, 2013
- Superphylum Arthropoda
- (jointed-legged metazoan animals [Gr, arthron = joint; pous = foot])
- Phylum Entoma
Classification of Crustacea and estimates of their numbers in North American freshwaters (Thorp & Covich, 1991)
|Taxa||Worldwide percentage found in freshwaters||Approximate number of species in the US and Canada|
|Subphylum Crustacea||<10%||ca. 1500|
| Class Cephalocarida||0%||0|
| Class Branchiopoda|
(8 orders; includes cladocerans)
| Class Remipedia||0%||0|
| Class Maxillopoda|
| Subclass Copepoda||<15%||>200|
| Class Ostracoda||>50%||420|
| Class Malacostraca||ca. 10%|| |
| Superorder Pancarida|
| Superorder Peracarida|
Amphipoda and Isopoda)
| Superorder Eucarida|
Diagnostic features of Crustacea (Mackie, 1998)
Nearly 4000 species of crustaceans
inhabit freshwaters around the world, occupying a great diversity of
habitats and feeding niches. Within pelagic and littoral zones, water
fleas and copepods are the principal macrozooplankton, and benthic
littoral areas shelter vast numbers of seed shrimps, scuds, and other
crustaceans. An omnivorous feeding habit is typical of crustaceans,
although there are many strict herbivores, carnivores, and
detritivores. Members of the subphylum Crustacea are characterized by a
head with paired mandibular jaws, a pair of maxillae, and two pairs of
antennae. Their appendages are often biramous.
Representatives of four groups of
malocostracean crustaceans can form major components of the benthic
fauna of some fresh waters.
Order Amphipoda (Scuds or side swimmers)
- Scuds are most commonly found associated
with aquatic vegetation. Scuds are sometimes confused with sowbugs, but
scuds are higher than they are wide and swim rapidly on their sides,
while sowbugs have flattened, oblong shaped bodies and crawl slowly
along surfaces. (Kellogg, 1994)
- Hyalella Azteca is so ubiquitous and abundant
that their absence in considered a reliable indicator of lake
acidification. They can tolerate pH's down to 6.5, at which point they
begin to disappear. Diporeia hoyi is found only in deep, cold,
oligotrophic lakes. However, their preference for deep waters appears
to depend upon their requirement for cold water because they have been
found in profundal zones with less than 7% oxygen saturation. (Mackie, 2001)
Order Isopoda (Aquatic Sowbugs)
- Large numbers of sowbugs (also known as
pillbugs) are often an indication of organic enrichment. Sowbugs are
sometimes confused with scuds, but sowbugs are wider than they are high
and walk slowly along surfaces. (Kellogg, 1994)
- Although the order is often considered an indicator of moderate enrichment or subpollution, only certain species, such as C. communis and C. racovitzai, can be considered such. (Mackie, 2001)
Order Mysidacea (Opossum Shrimps) (Mackie, 2001)
- They are almost exclusively marine
except for a few species that are native to deep, cold oligotrophic
lakes, such as the Great Lakes and the Finger Lakes of New York State.
- When lake productivity is high, the mysid life cycle
is 1 to 2 years in duration; when productivity or temperature are low,
mysids may require up to 4 years to complete their life cycle.
Order Decapoda (Shrimps, Crabs, etc.)
Family Cambaridae (Crayfish)
Most species live for approximately 2 years although certain species may live up to 6 or 7 years. (Kellogg, 1994)
Family Palaemonidae (Freshwater Shrimp)
Although infrequently encountered in riffle
areas of streams, freshwater shrimp may be common in slow moving
brackish or freshwater streams coastal or lowland areas. (Kellogg, 1994)
Class Branchiopoda, Order Cladocera (Water Fleas) (Mackie, 1998)
Holopedium gibberum is characteristic of acidifying lakes and waters low in calcium.
Class Ostracoda (Wetzel, 1983)
The ostracods are small, bivalved
crustaceans usually less than 1 mm in size, which are widespread in
nearly all aquatic habitats. Ostracod densities increase in more
productive lakes (to >50,000/sq.metre).
Micrographs of some crustaceans:
Order: Ostracoda (seedshrimps)
Order: Branchiopoda (cladocerans [water fleas]); Family: Chydoridae; View: lateral
Class: Copepoda; Left: Order Cyclopoida; Right: Order: Calanoida
References and web URLs:
- Hutchinson, G.E. 1993. A Treatise on Limnology. Vol. IV, The Zoobenthos. Ed. Y.H. Edmondson. John Wiley & Sons, Inc. Xx, 944pp.
- Kellogg, L.L. 1994. Save Our Streams.
Monitor's Guide to Aquatic Macroinvertebrates. Second Ed. Izaak Walton
League of America. 60p.
- Mackie, G.L. 2001. Applied Aquatic Ecosystem Concepts. Kendall/Hunt Publishing Company. xxv, 744 pp. ISBN 0-7872-7490-9
- Narf, R. 1997. Midges, bugs, whirligigs and others: The
distribution of insects in Lake "U-Name-It". Lakeline. N. Am. Lake
Manage. Soc. 16-17, 57-62.
- Pennak, Robert W. 1978. Fresh-Water
Invertebrates of the United States. Second Edition. John Wiley &
Sons. ISBN: 0-471-04249-8. xviii, 803p.
- Peckarsky, B.L., P.R. Fraissinet, M.A. Penton, and D.J. Conklin,
Jr. 1990. Freshwater Macroinvertebrates of Northeastern North America.
Cornell Univ. Press. xii, 442pp.
- Thorp, J.H., and Covich., A.P. (eds.) 1991.
Ecology and Classification of North American Freshwater Invertebrates.
Academic Press, Inc. ISBN:0-12-690645-9. xii, 911p.
- Wetzel, R.G. 1983. Limnology. 2nd ed. Saunders College Publishing. Xii, 767pp, R81, I10.
- Williams, D.D., and Feltmate, B.W. 1992. Aquatic Insects. CAB International. ISBN: 0-85198-782-6. xiii, 358p.
- Mandaville, S.M. 1999.
Bioassessment of Freshwaters Using Benthic Macroinvertebrates-A Primer.
First Ed. Project E-1, Soil & Water Conservation Society of Metro
Halifax. viii, Chapters I-XXVII, Appendices A-D. 244p.
- For the entire Report, download all the files in the subdirectory, Primer1
- Chapter XXII: Subphylum Crustacea (cladocerans [water fleas], shrimps, copepods, amphipods [scuds], sow bugs, crayfish, fish lice)
- Tree of Life- Crustacea
- New York Department State of Environmental Conservation
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