Fish passage research for Southern Hemisphere species lags significantly behind that for Northern Hemisphere species. This is despite there being a relatively high prevalence of diadromous species relying on free access between marine and freshwater environments to complete their life-cycles. With an emphasis on New Zealand experiences, this paper discusses some of the challenges associated with transferring knowledge and methods from the Northern Hemisphere, and highlights the need for novel approaches for progressing fish passage research in the Southern Hemisphere.

One of the most significant challenges is that many Southern Hemisphere fish species undertake their main upstream migrations as small bodied juveniles (20-60 mm TL). This precludes the use of most state-of-the-art biotelemetry methods (e.g. PIT and acoustic tagging) for studying behaviour solely due to the tags being too large. It also means there is a need for greater focus on the impact of small instream structures, e.g. culverts, on connectivity. A further constraint is that the fundamental ecology and basic swimming capabilities of many Southern Hemisphere fish species are poorly understood, limiting the ability to establish whether existing solutions are transferable.

The unique behaviours of some Southern Hemisphere species (e.g. the ability to climb wet surfaces) opens up new avenues of fish passage research and a need for innovative approaches to finding solutions. To maximise these opportunities there is a need to embrace inter-disciplinary approaches and improve knowledge sharing. There is also a need to engage with end-users to ensure effective uptake of new solutions.