In the mid-19th century, trout were the new guy on the block in streams occupied by galaxiids. However, the new neighbour was not a shy sort. It has spread widely, pushing native fish to the edges of suitable habitat.
Trout were introduced by European settlers for sport fishing. They thought that they were doing right thing by adding some life to seemingly empty New Zealand rivers. Secretive and shy galaxiid were too cryptic to be properly noticed.
Scientists suggest that trout would probably not be introduced these days, however, people have grown to love trout and many are proud of their presence in NZ rivers.
So trout are here to stay ... the question is whether galaxiids will be able to stay as well.
Management of the purity of freshwater alone cannot insure survival of its fauna. Not only must current human impact be mitigated, but interactions between native and introduced freshwater fish should be regulated. Assessment of the future of native fish cannot be left to the Department of Conservation alone; the protection of galaxiids will require greater influence in issues of water use (e.g. the amount of water that can be taken from rivers, and the minimum required flow), presence of sport fish, and how some headwater streams look (barriers to trout migration and fencing might be installed). It can even become a concern for big industry (attention given to native fish could compromise power company's plans for new dams).
GALAXIIDS COULD & SHOULD CONCERN US ALL.
Galaxiids in public
The topic of galaxiids does not appear often in public discussions. Where it has appeared in the news lately includes in discussions like:
1. Navis Dam controversy – plans for the dam were rejected because of presence of unique galaxiid species in the area. Fish and Game “employed” galaxiids for the protection of trout sites.
2. Decline of whitebait
3. Run-off decreasing water quality (irrigation run-offs, stock access to waterways)
4. Destruction of whitebait spawning grounds
5. Cleaning rivers – often mention native fish
6. Destruction of wetlands
7. Gravel extraction
8. Low flows
Protection/ Trout eradication
In order to protect galaxiids, DOC wants to ensure that existing populations are safe from predation. Their current strategies for galaxiid conservation include: improving situations with unfenced river banks on agricultural land, installation of barriers to trout passage in some of headwaters, and eradicating invasive trout from some headwater streams. They hope to eradicate trout from some headwaters where galaxiids are common and trout are too small for angling. However, trout eradication even from a small stream is difficult. Electric fishing doesn’t ensure that all predators of native fish are caught, it works well only in clear shallow waters. DOC suggests the fish poison rotenone is an effective method of trout eradication. Rotenone is a natural plant toxin used for centuries by indigenous people of Southeast Asia and South America for the harvesting of fish for human consumption. It is considered one of the most environmentally benign toxicants available and is commonly used to control unwanted fish species as well as garden pests. However, it is not widely implemented by DOC, due to the long approval process, cost, and fear of lack of public understanding. A Recovery Plan for non-migratory galaxiids was developed and published in 2003, however, it has never been fully implemented. DOC works with local government, like the Otago Regional Council (ORC). Together they work with farmers on the protection of galaxiid spawning sites. DOC, ORC and Fish and Game collaborate on the construction of barriers between trout and galaxiid populations.