Marine NZ

Red crayfish observation statistics at Great Barrier Island and Tawharanui Marine Park

In January I carried out 7 dives in suitable crayfish habitat in and around Port Fitzroy on Great Barrier Island, and one at Tawharanui Marine Park.  Total dive time was 401 minutes at GBI and 12 minutes at Tawharanui.  The number of legal and sub legal red crayfish seen in each area is indicated in the table below.  Total crayfish seen per dive minute was 0.03 at GBI, and 2 at Tawharanui.  The largest crayfish seen at GBI was just under the legal size limit.  At Tawharanui the largest seen was just over 3 kilogrammes.  (see photos below).  This data suggests 66-times more crayfish are likely to be seen per dive minute at Tawharanui than at Great Barrier Island.

 (Left) Largest Crayfish seen in 7 dives at Great Barrier Island.  (Right) Largest Crayfish seen in 1 dive at the Tawharanui Marine Park.

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