A juvenile trout from
Otago Fish and Game's Macraes Hatchery has tested positive
for the same bacterial disease causing illness and death in
lampreys in Southland.
The identification comes just weeks after Fish and Game
released about 3500 trout from the hatchery into 10
reservoirs and lakes in Otago as part of its regular stocking
programme.
Otago Fish and Game manager Niall Watson said those fish were
released in September and had no signs of illness.
"No [further] fish liberations will proceed until the
situation is clarified," he said.
There have been concerns about the possibility of the
Aeromonas bacteria spreading from the Mataura River, near
Mataura, where the sick lampreys (kanakana) were first
discovered last month.
The hatchery manager found a poor-conditioned trout with
lesions at the hatchery last week and sent it to the Ministry
of Agriculture and Forestry (Maf) for testing.
Maf biosecurity response manager Glen Neal said the trout was
the only fish affected among the thousands being raised in
the hatchery's stock waterways for recreational fishing.
"The detection of this strain of this bacteria in a trout is,
unfortunately, not unexpected. This has not been found in any
other species to date."
The bug was known to affect a range of fish including trout,
eel, salmon, whitebait and kokopu.
It was a difficult process to identify the particular strain
of the bacterium, which had not been found in New Zealand
before, he said. It did not pose a direct risk to human
health but eating fish that appeared unhealthy was not
recommended.
Two other fish with suspicious markings had been sent for
analysis but there had been no further deaths. The other 3000
trout appeared healthy, he said.
Fish and Game had stepped up monitoring of the hatchery stock
and had restricted access to staff involved in essential
management, he said.
Maf was asking anglers to report any dead or ill fish and
reminding them of the importance of checking, cleaning and
drying equipment and clothing when moving between waterways.
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