Sunday, March 17, 2013

Fairy Shrimp and Brine Shrimp in BC: new checklist now available

A new checklist of the fairy shrimp/brine shrimp of BC (Order Anostraca), by Ian Gardiner, is now available on the E-Fauna BC checklists page.  To date eight species have been reported for the province.  Species in the genus Artemia are generally referred to as brine shrimp, while other genera are referred to as fairy shrimp.

These tiny crustaceans are easily recognized, filter-feeding crustaceans in the Order Anostraca that are found in fishless vernal pools and hypersaline saline lakes and ponds around the world. Defecto (2002) provides the following description of brine shrimp.

"Brine Shrimp are distributed throughout the world, occurring on every continent except Antarctica (Browne and MacDonald 1982).  These tiny shrimp inhabit hypersaline lakes and ponds of varying ionic composition, temperature, and altitude (Triantaphyllidis et al. 1998).  Found in terminal inland salt lakes and commercial salterns, Artemia can tolerate salinity up to five times higher than seawater (Browne and Macdonald 1982).  In addition, brine shrimp have been found in waters high in carbonate with pH values as high as 10 (Cole and Brown, 1967).  Artemia populations have been observed at altitudes from below sea level to approximately 4500 meters above sea level in both humid and arid climates (Triantaphyllidis et al. 1998). Because Artemia are susceptible to predators such as fish, birds and other invertebrates, they typically will inhabit water with ionic compositions too high for their major predators to tolerate (Browne and Macdonald 1982)."

In BC, these shrimps have been reported from several saline lakes and ponds. Saline lakes and ponds are distinctive and are easily recognized from a distance by the white ring of encrusted salts and minerals around their shorelines. This ring expands as summer draw down occurs and water evaporates, leaving the lake or pond dry and encrusted.  Examples of saline lakes and ponds in BC include Spotted Lake, Mahoney Lake and Goodenough Lake.

 Goodenough Lake, BC, photo by Ian Gardiner

"Mating swarm of Artemia franciscana. The haemoglobin production (red colouration) is in response to the lowered oxygen content of the water resulting from the high concentration of dissolved solids".
Photo by Ian Gardiner

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