North Australian FISH FINDER forums

Some graphs here from BOM showing historic rainfall at some NT gauges. Given the importance of rainfall, these graphs hopefully bode well for barramundi fishing on the long term, keeping in mind increasing heat might have effects eg greater waterhole mortality.

Graphs are Magela Creek (East Alligator tributary), Katherine River (which is really just the upper Daly River), Douglas River (lower Daly River tributary), and Margaret River (Adelaide River tributary).

If you don't already know, wet season rain is of vital importance to the Top End environment. Long wet seasons generally promote more breeding/growing in bait and predators.

Might upload from other stations on this thread later.

Separately, from ChatGPT, re Top End rainfall ...

Increase in annual rainfall over past decades
The Top End has had a statistically measurable increase in annual rainfall. For example, a climate-guide report from the Northern Territory Bureau indicates that from a comparison of two 30-year periods (1959-1988 vs 1989-2018), annual rainfall increased by about 110 mm (≈11%), from around 940 mm to ~1050 mm.

Bureau of Meteorology - wet season / monsoonal rainfall increase
The wet season (monsoon period) rainfall has also increased in some key stations. For instance, Darwin’s wet season rainfall between Nov-Apr increased by ~146 mm compared to the earlier 30-year period. Daly Waters increased by ~81 mm.
Bureau of Meteorology

Seasonal shifts and variability
Rainfall in the build-up (the period leading into the wet season, often Oct-Dec) appears less reliable in parts of the Top End, especially the eastern part. That is, large inter-year variability and “false starts” of monsoon rains have been more common. There is also evidence that the earlier and later parts of the wet season (and perhaps associated with the monsoon onset) have become more variable. Some studies note a decrease in rainfall in the early and late wet season in certain parts.

Recent years
In 2024, for example, the Northern Territory as a whole saw rainfall totals well above average, and in some parts of the Top End or NW NT, the highest on record.

What is not fully settled / uncertainties
How much of the observed increase is due to long-term climate change vs natural decadal variability (e.g. ENSO, the Indian Ocean Dipole, Pacific Decadal Oscillation) is still being explored. The timing of the monsoon (onset, duration, breaks) is variable and some trends (later onset in some years) might be emerging, but the confidence is lower. The spatial differences are strong: some parts of the Top End (east vs west) show different trends. Some subregions have more reliable increases; others are more variable.

Overall conclusion
Yes, the rainfall over the Top End has been trending upwards, particularly in the wet season / monsoonal rainfall period and in aggregate annual totals, over the past several decades. But the increases come with more variability—some years of low rainfall, shifts in when rain falls, and differences in how reliable parts of the region are.

So to summarise, while fish are dying off the SA coast for who knows what reason but probably related to climate change, the Top End's rainfall-reliant fishing habitat is looking good.

I haven't seen the data presented like that before, pretty cool

Amazing what's on BOM when you dig around.

Mary River ...