Kingfish make the leap
Anti-fouling trials begin
Farming bath sponges in Fiji
Understanding freshwater crayfish
Sounding out pelagic fish
Paranephrops planifrons
Freshwater crayfish or koura are an important kai (food) resource for Māori and a vital component of healthy natural freshwater ecosystems.
Our kingfish fingerlings being delivered to Island Aquafarms Ltd in the Marlborough Sounds for on-growing.
Understanding pelagic fish behaviour is essential to accurately estimate their abundance using aerial sighting techniques. The development of relative abundance indices for pelagic species is a current objective of several Ministry of Fisheries projects.
We recently began surveys with sonar equipment to map schools of pelagic fish such as mackerels, kahawai, trevally, skipjack tuna, pilchards, and anchovies in the Bay of Plenty and Bream Bay. We are using multi-beam wide-angle sonar to estimate the relative sizes of fish schools and study school movements.
With increased demand for natural bath sponges, sponge-farming is the only sustainable alternative to wild harvests, and a potentially valuable source of income for small island communities.
The farming method is based on cropping sections (‘clones’) of wild bath sponges, leaving behind a living sponge. The clones are grown to marketable size on artificial structures.
NIWA, in collaboration with Scion and our industry partners, Altex Coating Ltd and Quality Equipment Ltd, is trialling natural anti-fouling products for use in marine paints and plastics.
Current biocides prevent fouling by killing the fouling organisms, and there are concerns, due to their tendency to accumulate in the environment, that they may harm related non-pest species.
However, studies have shown that many non-mobile marine invertebrates, particularly sponges, remain largely unfouled because they release natural compounds that deter settlement of fouling species, rather than killing th
