Freshwater fish calendars
NIWA's publication "Freshwater Fish Spawning and Migration Periods" is designed to help people working near freshwater to minimise effects of their work on freshwater fish species.
The calendars contained within the publication cover 41 key freshwater fish species in New Zealand – 34 are native and the other seven are sport fish, including trout and salmon. The two New Zealand species of koura have also been included.
In addition to the calendars, there are also fact sheets listing important details about each species, including conservation status and preferred habitat, and a ranking given to each species based on their ability to adapt to changes brought about by forestry activities.
Most of New Zealand's native fish species are less than 150 mm long, and many move between fresh water and the sea as part of their life cycle. Being able to get from one to the other is crucial for the distribution and survival of a species.
The calendars were produced with the assistance of funding from the Ministry for Primary Industries, outline the spawning range for each species, the migration of adults to spawning habitats, and the upstream migrations of juveniles to adult habitats.
Species are assigned rankings based on based on their susceptibility to turbidity, sedimentation and afforestation which can affect such things as migration, feeding, foraging and stream morphology. The rankings in each category have been added together and an overall score applied. There are 20 species which score 40 or above, and considered highly sensitive. A further nine scored between 30 and 39.