Issue 10, 2005

19 April 2007 - 11:29am

Science Centres: Aquatic Biodiversity and Biosecurity

Algal invasion

New quick ID guides

Lessons on a reef

Take a look into lakes

New quick ID guides
NIWA has produced guides for a range of freshwater plants, algae, fish, and invertebrates, so freshwater scientists around the country can make quick and accurate species identifications. The set include guides for identification at coarse levels (e.g., freshwater fish families and major groups of freshwater algae), as well as detailed guides for genus and species level.

Algal invasion
Didymo growth in the lower Waiau River, showing how the alga completely covers stones and aquatic vegetation. It’s been dubbed ‘rock snot’ and described as ‘looking like wet toilet paper’. A northern hemisphere diatom (a single-celled freshwater alga) which NIWA identified in two popular trout fishing rivers in Southland is proving ominous. The diatom Didymosphenia geminata (didymo) was initially spotted in the lower Waiau River, Southland, during a survey by NIWA and Southland Fish & Game staff for Meridian Energy.

Take a look into lakes
Tracey Edwards (NIWA) surveying vegetation in a lake. NIWA’s latest web-based resource shows the condition of more than 50 lakes around the country. The lake assessments were produced using the LakeSPI (Lake Submerged Plant Indicators) management tool developed by NIWA. The web-pages include a LakeSPI summary for each lake, where bar graphs (see diagramto the right) show how close a lake is to its best possible condition (smiley face icon), or how badly the lake has deteriorated (frowned face icon). For example, this LakeSPI summary for the badly degraded Rotorua lake, Lake Rotoiti, i

Lessons on a reef
NIWA is helping teachers spread the lessons learnt from our biodiversity work with children at Makaurau Marae, Ihumātao, Manukau. When the Mangere sewage treatment ponds were built in the 1960s, the marae’s traditional kai moana reef disappeared under a dense covering of Pacific oysters and mud because there was less water circulation past the reef.