Friends of the Cawthra Bush
Greater Mississauga Area
Pages of Special Interest;
Other Table of Contents;
( the details about them )
The May 6/99
from Prof. D. Dudley Williams, Ph.D., D.Sc., Professor of Zoology (Fairy
Ed Hendrycks, Research Assistant, Research Division, Canadian Museum of Nature. Supplies some general back ground on Fairy shrimp. His expertise is in Amphipods.
Fairy shrimps belong in the order Anostraca, which means "no carapace", as they lack a carapace. They have large, stalked eyes. They are often sold in pet stores as instant shrimp or sea monkeys. The eggs are amazingly resistant and can withstand dessication for long periods of time. The brine shrimp Artemia salina is often sold as eggs, which when immersed in salt water of the right concentration, hatch into nauplius larvae which can tolerate salinities from fresh water to saturated brine. This is the only species that is found in saline lakes, as this group is strictly found in freshwater. They feed on microscopic algae, diatoms, protozoans, rotifers, bacteria and detritus which they gather as they swim in an inverted position. However, they have been seen gnawing on larger particles like dead tadpoles, earthworms, mollusks and frog eggs.
The feathery legs are rhythmically waved anteriorly to posteriorly and propel the animal forward, while the leg bases filter out and manipulate the algae. The 11 pairs of swimming legs are flattened and leaflike in appearance, hence the name "phyllopods" and "gill feet". The male has large structures called claspers, which are modified 2nd antennae, to hold onto the female prior to mating. They swim in pairs until the female moults, then the eggs are released and the male can fertilize them. The males usually die a few hours after copulation. The eggs are held by the female for some time and then drop to the bottom and may remain dormant for a year as the temporary ponds or vernal ponds dry up each year. These small bodies of water are usually full of water in the spring and dry up as conditions get warmer and drier in the summer.
E. bundyi apparently prefers clear ponds and pools, while other species can be found in muddy waters. Eubranchipus spp. are all restricted to North America. Since these animals are basically defenseless, they are not found in lakes as fish would decimate there numbers quite quickly. This is one reason why they can reach high densities in vernal ponds, ditches and prairie pools as these temporary bodies of water usually do not have large predators which would feed on fairy shrimps. Some of the fairy shrimps can reach 25 mm long. They are fascinating to watch in an aquarium and are easy to maintain.
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Web-sites to visit for both Fairy Shrimp and vernal ponds (mostly from the States);
Fairy Shrimp (general);
Vernal ponds (general);
http://library.advanced.org/2943 or as they call it the "Wicked Big Pond"
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