New Zealand crayfish



Good news, Clint has launched his site on New Zealand Native Fish and Crustaceans

Well our site is expanding, I no longer feel this is 'Dave's Crayfish Downunder' , I am truly becoming just the Web-master. These contributions are from Clint McCullough the Farm Manager of Rakaia Salmon Ltd, New Zealand. Clint is also the Vice President of the New Zealand Native Freshwater Fish Society. Clint can be contacted here.


Paranephrops planifrons, New Zealand has two freshwater crayfish species, with this species being
found throughout the North Island, and in the north of the South Island. They are largely nocturnal in their habitat of lakes, streams, and wetlands, where they feed opportunistically on aquatic insects and vegetation.
Freshwater crayfish are thought to function as a "keystone" species, where they modify the environment to permit more other species to exist than if they were not present. These crustaceans also provide an important food source for larger fish and waterfowl as well. Koura are non-migratory, andcarry their eggs and then their developing young under their tails. Juveniles are released as perfect miniatures of the adult, able to fend for themselves immediately. Lengths are greatest in lakes (around 160 mm), with ages over 3 years not being uncommon.

Conservation status: Koura have been lost from a significant proportion of their historical range through habitat deterioration and the introduction of exotic fishes.

Paranephrops zealandicus
Southern Koura are found through the east and south of the South Island to Stewart Island. They are significantly larger, spinier, (about 80 min long) and have distinctively, hairy robust pincers. The biology of this species is though to be very similar to that of the Northern Koura, although less is known of this species. For more information visit Clint's New Zealand Native Fish site.

Conservation status: Freshwater shrimp are common in many lowland streams and rivers in New Zealand, and are fairly tolerant of the degraded conditions often found in these waters. For more information and to see more of Clint's photos of their native fish visit the KAIPATIKI ECOLOGICAL RESTORATION PROJECT

(Hymenosomatidae: Amarinus lacustris)
The only species of freshwater crabs in New Zealand has a patchy and is found in a variety of habitats; from lakes, to some slow-flowing streams and rivers including the lower Waikato River. They are also found in south-eastern Australia and the Norfolk Islands. First discovered in Lake Pupuke in the Auckland region, they have recently been noted also in streams in that area. Although fairly tolerant to completely fresh or saline conditions, they are mainly found in brackish waters over their distribution, probably as a result of little surveying having been done.
Unlike marine crabs, young hatch directly from the eggs carried under thefolded tail of their mothers as with freshwater crayfish. They aredetritivores, feeding on both animal and vegetable material found in the organic silt of their habitat. They grow to around 10 mm in shell width.

Conservation status: Considered to be threatened, there are probably many as of yet unknown populations still to be discovered. Some populations are thought to have been lost to predation from introduced trout