Lake Omapere

Forest and Bird, Issue 309, 1 August 2003, Page 3

Lake Omapere

Tauranga

—BASIL GRAEME

The Lake Omapere article (Feb 03) was short on facts. The article failed to mention that the lake was initially drained and lowered by several metres to develop dairy farms. The pasture shown in the photograph is on the old lake bed! Denuded of its riparian vegetation, awash with stock effluent and the fertiliser runoff from the surrounding paddocks, aquatic weed species flourished in the now shallow lake. According to the February article, the ‘white knights’ to the rescue are 20,000 introduced grass carp. Grass carp are just one more abuse in the history of this lake. Their first preference is for native and usually uncommon aquatic plants. Less palatable introduced weeds will only be eaten after palatable native plants are cleaned out and mob

stocking forces the fish to feed on weeds. The habitat of native invertebrates, whitebait, fish and wildfowl is destroyed. Forest and Bird has consistently opposed the introduction of grass carp. These fish pose a threat to vulnerable native wetland and drain habitats should they escape or be dispersed by rogue fish fanciers. Containment has failed at least twice and, while they are not supposed to breed in New Zealand, they have bred overseas where they were not expected to. Grass carp do nothing to fix the enrichment of the lake. Riparian retirement would help.