Published online: October 2021
Synthesis by: Dr Finnbar Lee, Research Fellow, School of Environment, University of Auckland (finnbar.lee @ auckland.ac.nz)
Īnanga, the most common and widespread whitebait species (left) and shortjaw kokopu, the rarest of whitebait species (right). (Credit: Finnbar Lee, André Bellvé)
Table1. Distribution and conservation status of the five whitebait species.
|Species||Distribution||DOC+ threat classification status|
|Banded kōkopu||Aotearoa||Not threatened|
|īnanga||Aotearoa, Argentina, Australia, Chile, Falkland Islands, New Caledonia||At risk – declining|
|Kōaro||Aotearoa, Australia||At risk – declining|
|Giant kōkopu||Aotearoa||At risk – declining|
|Shortjaw kōkopu||Aotearoa||Threatened – nationally vulnerable|
+Department of Conservation/Te Papa Atawhai.
Non-native species (primarily rainbow and brown trout), habitat loss/degradation and reductions in connectivity can all have negative impacts on whitebait; however, the relative effect of each of these threats is not well understood. Additionally, there is a lack of knowledge regarding some fundamental demographic processes, such as mortality rates across the life-cycle, spawning sites and behaviour for all species other than īnanga, ecology of the larval marine phase of all species, and the spatiotemporal structure of stocks. Further complicating matters, some of these processes vary among the different species. For example, giant kōkopu are slow growing and long lived, whereas īnanga typically complete their life cycle within one year. To make sound conservation decisions we must have a good understanding of the population dynamics of each of the species; there is an immediate need to quantify these unknown processes.
While there are many gaps in our knowledge regarding whitebait, discoveries are being made all the time, some recent highlights include:
- In non-fished rivers, while whitebait densities can be higher than in fished rivers, populations may be skewed towards smaller fish, likely due to competition for resources. This pattern suggests fish lost to whitebaiting may be partially offset by larger, more fecund adults in the fished rivers 
- Most whitebait spend part of their life cycle at sea, but not all individuals do this. Instead, a proportion stay in their natal river, even when they have access to the sea [2,3]
- The majority of īnanga die at the end of their first year after spawning, but a proportion may survive and reproduce in subsequent years; these individuals are typically large and therefore highly fecund 
The significance of these findings for the long-term persistence of the five whitebait species is uncertain but they represent interesting and important avenues of research, along with the fundamental gaps in our understanding discussed above. Ultimately, whether the changes made to the whitebaiting legislation result in changes to conservation status is hard to say given the lack of data on the relative impacts of threats. It may be that whitebaiting is somewhat of a red-herring and addressing threats faced by adult fish is orders of magnitude more important, or it may be that these changes to fishing regulations represent a way to quickly reduce impact and buy time to address more pervasive and problematic issues.
 Watson AS., Hickford MJ., & Schiel DR. 2021. Freshwater reserves for fisheries conservation and enhancement of a widespread migratory fish. Journal of Applied Ecology. https://doi.org/10.1111/1365-2664.13967
 David BO., Jarvis M., Özkundakci D., Collier KJ., Hicks, AS., & Reid M. 2019. To sea or not to sea? Multiple lines of evidence reveal the contribution of non‐diadromous recruitment for supporting endemic fish populations within New Zealand's longest river. Aquatic Conservation: Marine and Freshwater Ecosystems, 29(9), 1409-1423. https://doi.org/10.1002/aqc.3022
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Goodman J. 2018. Conservation, ecology and management of migratory galaxiids and the whitebait fishery: a summary of current knowledge and information gaps. Wellington (New Zealand). Department of Conservation. https://www.doc.govt.nz/globalassets/documents/conservation/land-and-freshwater/freshwater/conservation-ecology-and-management-of-migratory-galaxiids.pdf
Haggerty, JH. 2007. “I’m not a greenie but…”: Environmentality, eco-populism and governance in New Zealand: Experiences from the Southland whitebait fishery. Journal of Rural Studies. https://doi.org/10.1016/j.jrurstud.2006.11.002