 |
||||
|
|
 |
 |
|
|
||||
      |
Great Lakes Water Life Photo Gallery
|
Class Malacostra
The Malacostraca include about two thirds of all crustacean species, including all the larger forms. This page includes only the planktonic malacostrans of the Great Lakes - those which are frequently found in the water column.
Distribution and Habitat
x=present
| Image Link | Scientific Name | Common Name | Lake Superior | Lake Michigan | Lake Huron |
Lake Erie | Lake Ontario | Habitat |
| Order Mysidacea | mysids, opossum shrimp | |||||||
 |
Mysis diluviana | x | x | x | x | x | Found year-round in deep, cold, well-oxygenated areas. Rest near bottom by day. At depths over 150m, may remain pelagic and not migrate. | |
 |
Hemimysis anomala | I | I | Ponto-Caspian Invasive first found 2006 in Muskegon, MI and Oswego, NY. At depths less than 50m. Avoids light, prefers hard bottom and structures. Migrates both vertically and horizontally. | ||||
| Order Amphipoda | scuds | benthic | ||||||
|
Diporeia | x | x | x | x | x | Benthic animals burrowing into fine sediments. Males migrate upwards into the water column by night, but rarely cross the thermocline. Populations throughout the Great Lakes in decline coincident with zebra mussel invasion. | |
| Order Isopoda | aquatic pillbugs, aquatic sowbugs | near breakwalls or vegetated areas | ||||||
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.
Order Mysidacea - mysids, oppossum shrimp
Mysis diluviana (formerly M. relicta) |
|
The mysid species in the North American Great Lakes, formerly identified as Mysis relicta, has been renamed Mysis diluviana based on genetic studies (Väinölä et al. 1994; Audzijonytë and Väinölä 2005; Dooh et al. 2006) which separated Mysis relicta into 4 separate species Collectively these species are now referred to as the Mysis relicta group species. |
Mysis diluviana (formerly Mysis relicta) is a relict species that evolved from an isolated Mysis oculata population that was confronted with decreasing salinity in areas influenced by melt water during the retreat of glaciers during the Pleistocene Epoch. Mysis relicta is the only member of the order native to the Great Lakes Region. Prefers deep, cold waters with high levels of dissolved oxygen. Prefers temperatures 1-6C. May concentrate near the base of steep slopes. In waters <100 meters deep rests on or near the bottom by day. Possibly <25% of the population crosses the thermocline. At depths over 150m, may remain pelagic and not migrate. A truly omnivorous filter feeder, consuming algae, detritus, and other zooplankton. In the Great Lakes Mysis feeds primarily on phytoplankton and do not compete with young fish. A primary food source for various sculpin, coregonids, and burbot. Males die after mating, but females remain alive for several months. Eggs are held in a brood pouch (hence the name opossum shrimp). After 3-4 months, the eggs hatch into fully developed young. Length to 30mm. |
|
|
Hemimysis anomala |
|
Invasive 1st discovered in the Great Lakes in 2006. Native to the Ponto-Caspian region, with a history of invading across Europe. Impacts to the Great Lakes unknown at this time. Slightly smaller and more pigmented than the native Mysis diluviana. Shape of the telson (last body segment) distinguishes the two species. |
|
|
|
Order Isopoda - sow bugs
Great Lakes aquatic isopods are generally found near the bottom of vegetated areas or along breakwalls. Isopods are primarily scavengers, feeding on dead and injured animals, but also consume leaves, grass and aquatic vegetation. Isopod taxonomy for the Great Lakes has not been studied systematically, but Pennak reports over 80 U.S. freshwater species. Most species are found only in shallow water (<1 meter depth) but Asellus racovitzai has been found at 42m depths in the Great Lakes.
Order Amphipoda - scuds
Great Lakes amphipods are mostly benthic, hiding among rocks, vegetation and detritus in shallow water and avoiding light. Amphipods are voracious feeders. A few are predators on live animals, most consume detritus or plant material. Most grasp and hold materials to chew off pieces, a few are filter feeders and some are external parasites on fishers or colonial invertebrates. Pennak describes about 90 freshwater species in the U.S.
Diporeia (aka Pontoporeia affinis, P. hoyi, P. filicornis) |
|
Great Lakes Fish Community Impacted by Diporeia disappearance - GLERL Assessments of Benthic Macroinvertebrate Communities in the Great Lakes Ecology of Lake Whitefish and Response to Changes in Benthic Communities in Lake Huron Effects of Diporeia Declines on Fish Diet, Growth and Food Web Dynamics in Southeast Lake Michigan Long-Term Trends in Benthic Populations Pelagic-Benthic Coupling in Nearshore Lake Michigan: Linking Pelagic Inputs to Benthic Productivity |
Found in all the Great Lakes, though restricted to the deeper portions of Lake Erie. Generally found burrowed in the sediments (benthic). Males are frequently found in the water column, vertical migration is believe to be related to mating. Males die after mating, females die shortly after young are released. Young may require several years to mature. Length to 9mm. Non-selective detritus feeders. An extremely important component in the diet of most Great Lakes fish (forage fish, young lake trout, etc.). |
|
|
Indicates
a link to a non-GLERL NOAA website.
Indicates
a link to a non-NOAA website or content not generated by NOAA. NOAA is
not responsible for the accuracy of content. Please check Privacy and
Use Policies of the destination site.
USE NOTICE
NOAA | DOC | Privacy Policy | Disclaimer | Accessibility Statement |