Biodiversity in a disappearing river
Revealing the diversity of New Zealand hydrobiid snails
A new toxic dinoflagellate for New Zealand
New Zealand's cirolanid isopods - highlighting the diversity of these marine garbage cleaners
Enemy escapee or Trojan Horse? Looking for parasitic hitchhikers on an introduced crab
Species identification guides - identifying user needs
NIWA scientist receives hands-on training in marine alien-species research in USA
Isla Fitridge retrieving a settlement plate.
A settlement plate.
Isla Fitridge, a key member of NIWA’s Marine Biosecurity team, recently spent 3 weeks in Maryland, USA, working alongside staff in the Marine Invasions Laboratory at the Smithsonian Environmental Research Center (SERC).
Scientists there have been using passive surveillance techniques to monitor aquatic invasive species patterns at 21 sites in continental USA and Alaska and 2 sites in Australia for more than 3 years.
Charybdis japonica belly side up.
Charybdis japonica right side up.
Introduced species have a variety of effects on native plants and animals. Some become so abundant that they displace native species or alter their habitats.
One explanation of why introduced species do so well is that they arrive in a country free from natural enemies, such as parasites and diseases, which control their abundance in their native region.
A recent survey of user needs for tools to identify freshwater biota has helped to prioritise groups of aquatic plants and animals requiring future research.
Bathynomus giganteus, a Caribbean species, showing the size attained by these whale-scavenging isopods (Bathynomus is not yet known in New Zealand waters).
Isopods are usually inoffensive small animals like the slaters that live under stones or leaf litter in gardens and forests. Fishers and anglers know isopods better as parasites of marine fishes and call them sea-lice, tongue-biters, or fish doctors, but one of their most significant roles is that of scavenger.
Have you ever wondered what happens to the dead whales, fish, and all the other carrion that sinks to the sea floor?
Disappearing flows in the middle reaches of the Selwyn River. Photos were taken at the same location in November 2003 (top) and February 2004 (bottom).
NIWA scientists are studying the environmental consequences of extreme low flows in the Selwyn River, south of Christchurch. Of particular interest are the effects of seasonal drying and wetting of the riverbed on aquatic biodiversity values.
The Selwyn River drains the central Canterbury foothills, and flows – sometimes – for 60 km across the Canterbury Plains to Lake Ellesmere.
Some of the new species of Hydrobiidae currently being described. Top to bottom: species belonging to the genera Potamopyrgus, Opacuincola, and Leptopyrgus.
Recent research into the taxonomy of New Zealand hydrobiid snails has uncovered remarkable radiation in infrequently sampled freshwater habitats such as seepages, springs, and groundwaters. Little research has been done on this group in New Zealand, which has long been suspected to contain many undescribed taxa.
Lateral view of a cell showing ‘droop nosed’ look of a Concorde aircraft.
In the late spring of 2002 an undescribed Karenia species was found in the Hauraki Gulf in an algal bloom that contained several dinoflagellate species – Karenia brevisulcata, K. mikimotoi, and Nocticluca scintillans (see Aquatic Biodiversity & Biosecurity No. 3). The bloom coincided with the death of a large number of midwater and bottom-dwelling estuarine fish – parore (mangrove fish), flounder, yellow-eyed mullet, eel, goby, and spotty.
