Freshwater fish field day: Life found in a Waipu stream

09 May, 2022

It was a morning all about water for the 30 lifestyle block owners, farmers and community group members who shook off the rain to attend the Waipu River Catchment Native Freshwater Fish Field Day on April 28 at Waionehu Stream, McLeans Road, Waipu.

The purpose of the event was to share tips and techniques for restoring the health of waterways, offer support for getting the work done and kickstart a korero, possibly leading to the formation of the first catchment groups in the area. Representatives from Patuharakeke, Piroa-Brynderwyns Landcare Group, Whitebait Connection, Fonterra, NZ Landcare Trust, Waipu Waters, Weed Action and Waipu About Tern came together to deliver the field day.

The number one tip was to appreciate that every site is different. For this particular site, slowing erosion and combating weeds – such as kikuyu, alligator weed and nasturtium – through native riparian planting would be a great first step. Planting not only provides habitat for native fish, it also creates shade and reduces water temperatures in the stream.

Humane fish traps were set the day before, pulled out during the event and decanted into containers so attendees could enjoy a closer look at the inhabitants of the stream. The species identified included īnanga (native), redfin bully (endemic), toitoi or common bully (endemic), tītarakura / tīpokpoko or giant bully (endemic), kōeke or freshwater shrimp (endemic), tuna kūwharuwharu or longfin eel (endemic) and tuna hinahina or shortfin eel (native).

The fish were then released back into the awa, with some of the tuna choosing to slide home early down the grassy bank, much to the delight of the audience who were able to witness how these species move across land. This marks a key part of their life cycle – tuna heke (migrating eel) make an epic journey to the middle of the Pacific Ocean to spawn and die, leaving their offspring to return on the currents to Aotearoa. All of this while overcoming barriers to migration such as culverts, dams and water pumping stations – a fate they share with whitebait and other migratory species.

Aotearoa has more than 50 native freshwater fish species and about 70 percent of these are Threatened or At Risk, according to the Department of Conservation. Our sports fish, such as trout and salmon, also need to be able to migrate up and down stream to complete their lifecycle.

Peter Gibbs, local landowner, was pleased with what the traps revealed: “It is so encouraging to see life in the stream. It’s amazing how nature can restore itself so quickly. Focusing on the health of the stream is a wonderful thing to share with our grandchildren.”

Event organisers would like to thank the very generous Liz and Peter Gibbs for allowing access to the Waionehu Stream next to their property.

Local farmer Mary Abercrombie looking at a redfin bully fish at the Waipu River Catchment Native Freshwater Fish Field Day. The redfin bully is a territorial fish and a good indicator of a healthy waterway. PHOTO/SUPPLIED