Potential uses of mussel farm nuisances
Tracking Pacific swordfish
Giving eels a lift
New plan for Bluff oyster fishery
Instant health check on mussel spat
An eel lift at Waitaki dam.
Longfin and shortfin eels support an important fishery in New Zealand, but numbers, especially of large longfins, have declined since the fishery’s heyday in the 1970s.
Among the many factors that may have contributed to this decline is the proliferation of obstacles such as weirs and dams, which block the upstream migration of juveniles from the sea where they are spawned.
Māori traditionally transferred juvenile eels (e lvers) above natural barriers, such as waterfalls, to enhance eel numbers.
Carina Sim-Smith holds the prototype glycogen monitor for mussel spat (at left).
Retention of juvenile mussels (spat) is a big issue for mussel farmers, with spat losses commonly exceeding 70%. Research has shown that poor nutrition is a major cause of losses of wild-caught mussel spat from mussel ropes.
NIWA and Sealord Shellfish Ltd have now developed a simple way to identify poorly-nourished spat in the field, as an alternative to complex laboratory tests.
Oyster boat
NIWA is working with the Bluff Oyster Management Company (BOMC), the Ministry of Fisheries and a broad range of community stakeholders to enhance the iconic Bluff oyster fishery.
NIWA has provided scientific support for a recently-drafted Fisheries Plan for Bluff oysters, one of three proof-of-concept Fisheries Plans developed by the Ministry of Fisheries and stakeholders.
Our input has been encapsulated on an interactive CD, which includes information about oyster and bonamia population dynamics, the Foveaux Strait environment and ecosystems, and effects of oyster dredging on se
NIWA scientist Stephen Brown inspects heavily fouled floats and mussel lines.
NIWA is helping marine farmers to get more value out of existing aquaculture space. Organisms that foul mussel farms are currently a waste of space, and a costly nuisance for marine farmers.
Sealord Shellfish Ltd commissioned NIWA to investigate the potential for developing bioactive products from fouling organisms growing on their mussel farms in Pelorus Sound.
NIWA surveyed eight of Sealord’s mussel farms, scattered from the inner to the outer reaches of Pelorus Sound.
Smart tags:
These 17 cm long tags can record temperature, depth, and light levels every 20 seconds for up to a year, then transmit a summary to overhead satellites to monitor the locations of the fish.
NIWA and Blue Water Marine Research (BWMR) are tracking swordfish in the southwest Pacific to improve knowledge of stock structure in this highly migratory species.
Broadbill swordfish are a valuable fish, targeted by tuna longliners in New Zealand waters.
Commercial swordfish catches in the southwest Pacific (about 20% of which is caught in the New Zealand EEZ) have declined in recent years.
