Few sockeye in Benmore and Ohau

Graeme Hughes
Graeme Hughes
The mystery of the sockeye salmon in Lakes Benmore and Ohau has taken another twist.

Almost none are spawning this year, compared with recent years in which a resurgence in numbers was seen.

The wild sockeye salmon died out in both lakes, but then suddenly reappeared in the thousands since 2006.

However, this year's sockeye salmon spawning survey had revealed "a confusing picture", Central South Island Fish and Game Council officer Graeme Hughes said.

Spilling from hydro-electricity lakes since January appeared to have affected salmon numbers and their locations, spreading them from Lake Benmore down into lakes Aviemore and Waitaki.

The usual spawning areas in Larch Stream, the Tekapo and Pukaki rivers have very few sockeye salmon, whereas they were estimated to number about 14,000 in 2008.

Mr Hughes said they were now being found in the Otematata River and Waitangi Stream, flowing into Lake Aviemore, and in the Aviemore spawning race and Awakino Stream at Lake Waitaki.

Recently, campers at Lake Aviemore's Waitangi boat harbour had rescued about 150 sockeye salmon from Waitangi Stream when it started to dry up.

"Despite the relocation of populations, the sockeye numbers I suspect are well below the 14,000 counted in the last aerial-ground count in 2008," he said.

The sockeye salmon, introduced into Lake Ohau tributaries in 1901, disappeared in the 1980s after the Lake Ruataniwha spillway was built, cutting them off from their traditional spawning streams in Lake Ohau.

They reappeared dramatically in Lake Benmore's Haldon arm in 2006, their revival a mystery.

They also returned to Lake Ohau.

Usually, they grow to about 1.5kg, but they can prove difficult for anglers to catch.

 

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