Actually we do have some species that survive through our summer. They are
not strictly Daphnia though. Daphnia belong to the group of crustaceans
called Cladocerans. There are about 100 species so far described in
Australia. The majority belong to the Daphniidae (Daphnia), Macrothricidae
and Chydoridae. But we also have representitives in the Sididae, Bosminidae
and Moinidae. How's that for a bunch of useless information? Anyway our
"summer Daphnia" is actually a "Moina" of which there are five or so
species. The species that turns up in our ponds is less than half a
millimetre long, brown to green (depending, I suspect, on what colour algae
it has eaten), and at times forms very dense blooms that last one to two
weeks. It persists for most of the year, but seems to be most prolific in
temperatures of about 25 to 35 degrees celsius. It is also tolerant of
salinities up to about 15 parts per thousand (about half seawater). And it
is great rainbow, blue-eye and goby tucker.
See ya
Rob Wager
Freshwater Fish Biologist
Raintree Aquatics Pty Ltd
Aquatic Environment, Fish and Aquaculture Specialists
1002 Caboolture River Road, Rocksberg, Queensland, Australia, 4510
Phone 07 5496 7939, Facsimile 07 5497 0022, International +61 7 5496 7939
Email raintree at closer.brisnet.org.au