Probe into flea in­va­sion

Central Otago Mirror - - FOOD FOR THOUGHT - MAR­JORIE COOK

The wa­ter in Lake Wanaka is a win­try 10deg, but de­bate over a sus­pected link be­tween an al­gal ’’lake snot’’ and an in­tro­duced North Amer­i­can wa­ter flea is heat­ing up.

Otago Re­gional Coun­cil lake stud­ies com­mence next week and if the link be­tween the al­gae (Cy­clotella bo­dan­ica) and the flea (daph­nia pulex) is con­firmed, the re­gional coun­cil, Guardians of Lake Wanaka and the Otago Fish and Game Coun­cil ex­pect a na­tional biose­cu­rity re­sponse.

Guardians chair­man Dr Don Robert­son is also call­ing for greater in­vest­ment from coun­cils and busi­nesses in wa­ter catch­ment and lake snot re­search. Otago Re­gional Coun- cil man­ager of re­source science Dean Olsen said the Min­istry of Pri­mary In­dus­tries had been ad­vised.

‘‘They have ac­knowl­edged that . . we will do this DNA work to see if it is an in­tro­duced species or not. They are the lead au­thor­ity deal­ing with in­cur­sions of non-na­tive species. Once we get these re­sults back . . if it is an in­tro­duced species, we ex­pect the re­sponse will change quite markedly,’’ Olsen said.

How­ever, it could be four to six months be­fore re­sults are known, ac­cord­ing to a up­date from Dr Gavin Palmer, the re­gional coun­cil’s di­rec­tor of en­gi­neer­ing, haz­ards and science.

In the ‘‘Where to from here’’ sec­tion of his re­port, Palmer says the al­gae was spread­ing through the South­ern Lakes and had eco­nomic im­pli­ca­tions for wa­ter sup­plies, re­cre­ation and tourism.

‘‘Lake snow also raises ques­tions around the po­ten­tial roles of bi­o­log­i­cal in­va­sions and en­vi­ron­men­tal change. The pos­si­bil­ity that Cy­clotella bo­dan­ica is an in­va­sive species poses sig­nif­i­cant biose­cu­rity im­pli­ca­tions to Otago and else­where across New Zealand,’’ Palmer said.

An­glers be­gan re­port­ing al­gae bloom in Lake Wanaka about 2004. Soon af­ter, it was con­firmed in Lake Dun­stan. Lake Wakatipu had its first con­firmed case in May and a sim­i­lar slime has now been re­ported in Lake Hawea, al­though that has not been con­firmed by anal­y­sis.

MAR­JORIE COOK

Guardians of Lake Wanaka chair­man Don Robert­son wants a Lake Wanaka man­age­ment plan.

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