The front-page article in yesterday’s Kapiti Observer, showing a photo of a local man peering glumly into the his near-empty whitebait net at the mouth of the Waikanae River, prompted me to think about whitebait decline and its historical causes.
But first of all, what are whitebait? Many New Zealanders (including myself, until embarrassingly recently) may vaguely assume that it is a type of small fish – but in fact it is the juvenile form of five species of the fish family Galaxiidae (the most common being inanga). The larvae of these galaxiids are swept down to the ocean where they hatch and the sprats (or whitebait) then migrate back up their home rivers. They seek habitats upriver where there is still plentiful indigenous forest cover, where the fish then mature.
The term “whitebait” was a term used in Britain, and was brought with the early settlers to describe the little fish they found in such abundance here. The journals of early immigrants referred to shoals of whitebait swimming upstream, darkening the water. There were reports of cartloads being caught, with excess whitebait used as garden manure, or poultry feed.
However, this abundance was short-lived. Concerns about declining catches began as early as the 1890s – though sometimes natural seasonal variability was confused with dramatic declines. In 1927 South Westland was referred to as the last stronghold of the whitebait.
The whitebait season this year on the Waikato River has been the poorest for many years … The cause of the scarcity of the fish is not apparent. This year a restricted season for the taking of whitebait has been prescribed, with a view to letting more of the fish up the river to develop and return to spawn…
Though unsure of the cause, the journalist correctly identifies the returning of the fish upriver to spawn as a key factor. Almost 80 years later, this is a factor central to a new discovery and possible solution for declining whitebait numbers made by Waikato scientists. Over the last century or more, we have created so many impediments in our waterways – most notably, culverts and dams – that in many rivers and streams, fish are no longer able to make this journey. This, combined with pollution, sedimentation, and the severe reduction of indigenous forest cover around our rivers, is a major factor in the decline of these and many other indigenous freshwater fish species.
Watch the video of this fascinating story by clicking here.
Photo top: The inanga, or Galaxias maculatus, the most common species of whitebait, by Ryan Photographic. Centre: Henry Gurr and his son whitebaiting on the Taieri River, 1926. Photograph taken by Albert Percy Godber. Not to be reproduced without the permission of Alexander Turnbull Library, ref. APG-1581-1/2-G. Bottom right: The ebullient Dr Bruno David and some his subjects in “the climbing fish experiment”. Photo: Environment Waikato.
Sources/further reading: Te Ara Encyclopedia of New Zealand