snails will be ok

Miner confident snails will survive

"by Lee Scanlon
Solid Energy is now confi dent a rare snail species it
moved from Stockton opencast mine will survive.
Solid Energy collected 6140 of the native land
snails, Powelliphanta augusta, from a ridgeline at
Stockton opencast mine in 2007 so it could mine the
area. It aimed to establish one new viable population
in the wild.
About 4000 snails were later released into four
areas at or near Stockton. About 1600 remain in captivity.
Solid Energy general manager, environment, Mark
Pizey, said latest monitoring suggested at least one
of the relocated groups could be self-sustaining. He
was confi dent the species was now safe, given survival
rates in the wild and in captivity.
Mr Pizey said the snails relocated in the wild were
growing faster than expected. Three years data from
the most promising area also suggested the survival
rate was between 82 and 95 percent. Survival rates
of between 80 and 85 percent were required for a
sustainable population.
In another year Solid Energy would have three
years data for other release areas.
At the same time, the Department of Conservation
(Doc) has been running a captive management and
research programme at Hokitika.
Doc had overcome the major diffi culties of raising
snails in captivity and annual survival rates were now
about 90 percent, Mr Pizey said.
The captive snails? diet had been increased from
one to about six worms a month. They now had 12
hours light and 12 hours darkness a day, instead of
being kept in the dark, and the temperature had been
increased from 8degC to 10degC.
The high rate of young snail deaths had stopped,
the number of juveniles was increasing and egg laying
had increased from 150 ? 200 eggs a year among
1600 snails to over 1000 eggs a year.
This summer alone, during the peak November to
March breeding season, more than 700 eggs were
produced.
Eggs took about 14 months to hatch. Looking after
the hatchlings created logistical problems, Mr Pizey
said.
?We can?t feed them on large worms. We have
to sort baby worms out of our compost systems. It
becomes very labour intensive for somebody with
a pair of tweezers ? it?s about 6000 baby worms a
month.?
Mr Pizey said there was no reason to keep any
more snails captive when experts were confi dent
they could survive in the wild. A decision on more
releases would be made in the next few months.
As few as 500-600 snails would remain in captivity,
for research and to act as a backstop in case something
went wrong in the wild.
He said the snail programme had moved from
?stumbling around in the dark? to ?multiple professionals
coming up with great results?.
?We now have a group of specialists in Doc. These
guys are now probably the snail wranglers of New
Zealand and possibly in this area of the world.
?So few people are doing this work, otherwise it
would have been easy ? we could have just pulled out
the textbook on how you do it.?
The current programme runs until 2016."

Good news for Bathurst once again from the Westport News, Thursday front page