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

Tuesday, March 12, 2013

Ever Looked a Fairy Shrimp in the Eye?

Ever looked a fairy shrimp in the eye?  Photographer Ian Gardiner took a close look at the Alkali Fairy Shrimp (Branchinecta mackini), below, and took some great shots.   View his other photos for this species here. Stay tuned for more on BC's fairy shrimps, inhabitants of our salt lakes and ponds.

Saturday, March 9, 2013

Ask An Expert: Brown Recluse Spiders in BC

 Hobo Spider (Tegenaria agrestis), photo by Robb Bennett.
Not so fearsome as thought.


 "You state on your site that there are no Brown Recluse Spiders in B.C.  I have a friend in Duncan bitten on the foot which was diagnosed as Brown Recluse bite... [and]...I know a fellow in Kelowna that was bitten a couple years back and he had the inside muscle on his lower arm taken out in the hospital, wrist to inner elbow...he was also diagnosed as Brown Recluse bitten............What is your response? Do we have a clone here in B.C.?.....submitted by Jamie

Dear Jamie,

It is certainly unfortunate that your friends have suffered disfiguring and debilitating medical conditions. 

It is also unfortunate that a small minority of medical professionals apparently continue to provide erroneous diagnoses of brown recluse spider bite in the absence of any credible evidence.  If an appropriate diagnosis had been made your...friend’s foot would almost certainly have healed ages ago and your.... buddy might not have had to have muscle tissue removed. 

Although I cannot diagnose what sort of medical conditions your friends have suffered, their conditions were definitely not caused by bites from brown recluse or other spiders. 

Over the last 20 or 30 years a large number of peer-reviewed articles published in professional medical journals, ranging from Canadian Family Physician to Lancet and the New England Journal of Medicine, have completely debunked the popular mythology surrounding brown recluse spiders and their bites, including establishing the following facts:
  • it is very rare for anyone to suffer a bite from a brown recluse spider, even in areas of North America where they are very common 
  • most true bites never result in medically significant issues 
  • it is exceedingly rare for a bite to cause tissue necrosis 
  • nearly all medical conditions that have been blamed on bites from brown recluse or other spiders are actually caused by other medical conditions completely unrelated to any sort of spider 
  • the medical conditions that have been mistakenly diagnosed as resulting from brown recluse spider bites are numerous and range from simple chemical and radiant heat burns, through antibiotic-resistant bacterial infections and flesh-eating diseases, to syphilis, various cancers, and anthrax 
  • erroneous diagnosis of a medical condition as being the result of a bite from a brown recluse or other spider usually results in inappropriate treatment which can delay healing and/or cause unnecessary suffering even to the point of death 
  • brown recluse spiders are not often found outside of their natural range in the south central United States and definitely do not occur anywhere in or near Canada.
I urge you to take the time to learn the facts about spiders and share the knowledge with your friends and their doctors.  Forget the mythology – no one needs to suffer as your friends apparently have.  

A few good websites that will help bring you up to speed on spider bite facts and fiction are listed here:    

  • Rick Vetter’s spider research website is absolutely the best place to find anything you need to know about brown recluse and other spiders of real or imagined medical importance - 
  • Colorado State University’s  “mystery bites and itches” website provides an excellent review of all sorts of beasts that have been fairly or unfairly blamed for causing medical concerns in humans.  The spider section is especially good. 
  • Finally, Rod Crawford’s “spider myths website” provides a good overview of a wide variety of myths and misinformation associated with spiders -
I sincerely hope that the information I have provided here is helpful to you and your friends. 

Robb Bennett, Ph.D., F.E.S.C.
Research Associate, Entomology 
Royal BC Museum