High rainfall totals return to the Top End

Recreational fishers across the Territory have been rejoicing with the best wet season we have seen for a few years. The excitement for good run-off Barramundi fishing has been reflected in the high numbers of trailers at boat ramps, especially over the past two weeks.  Rainfall for the wet season to-date (October 2020–February 2021) across the NT was 32% above the long-term average, and the highest since 2016-17.

Daly River NT, March 2021

Rivers and floodplains exploding with life

Heavy and persistent rainfalls allowed floodplains, waterholes and river catchments to saturate and create the kind of ecosystem connectivity that drives productivity in riverine and coastal fisheries, especially for Barramundi. Inundated and connected floodplains, means rejuvenation of habitats and the transfer of energy from the land into aquatic environments; supporting the abundance of life that is so important for the health and quality of the most iconic Top End of fisheries.

The Daly River, having reached a peak last week, has now started to drop and should be (rain dependant), accessible for great fishing in the near future.  The Daly has also witnessed the annual migration of Macrobrachium spinipes, otherwise known as ‘Cherabin’.  The migration of Cherabin plays an essential part in the river systems’ ecological health and highlights the critical linkage between freshwater and saltwater environments.  River flow plays an integral part in the reproduction and recruitment of these freshwater prawns, with the larvae released upstream taking advantage of strong wet season flows in a race against time to reach the saltwater environment. Individuals must reach more saline waters within 7 days to enable the larvae to complete a critical stage in their development, or they will die.  The migration of juvenile Cherabin returning upstream towards the waters where they were spawned, has been witnessed along the banks of the Daly in the past week. This redistribution of nutrient along the river  is great news for the fish, animals and people that rely on an abundance of Cherabin.

To find out more about this important and intriguing little prawn, check out the fascinating video below from Dr Peter Novak of Charles Darwin University. Dr Novak spent years monitoring and researching Cherabin, with his findings shedding new light on the lifecycle and ecosystem function of this popular, yet previously poorly understood species. 

Youtube Video (c) Dr Peter Novak, Charles Darwin University 

Barra on the move and catches on the rise 

Swollen rivers and increased catchment connectivity provides opportunities for mature Barramundi to travel from the billabongs and lagoons where they have held residence for the past few seasons to the lower reaches of rivers and estuarine/saltwater environments.

AFANT recently reported a strong surge in tagged fish recaptures as a result of improved conditions and catchability. Among a number of new reports just this week, we were thrilled to receive a tagged fish recapture from Braeden Priore-Smith.  As part of the Research Tagging Program, Fisheries NT tagged an 89cm barramundi in the Mary River lagoon in June 2020.  Earlier this week, on a fishing trip with his Dad, 13-year-old Braeden caught the same fish at the mouth of the Sampan creek, measuring in at 98cm, just 2cm shy of the magic metre!  The barramundi had travelled 102km downstream and grew 9cm in 255 days.  Braeden will receive a recapture certificate and and AFANT/Reidys “I caught a tagged fish” lure prize, which is sponsored by our program partner Inpex Ichthys LNG.  Thanks for reporting the recapture Braedon, we hope your next big catch cracks the 1 metre mark!

Braedon Priore-Smith, 98cm Barramundi, Sampan creek NT

Map image supplied by Research Tagging Program Partner – InfoFish

An interesting side note to Braeden’s capture, was the report of another tagged fish recapture from the Sampan mouth one day prior.  This 100cm fish had also originally been tagged by Fisheries NT in June 2020 at the Mary River Bridge Lagoon.  It could be suggested that the fish may have travelled as part of the same cohort or pulse of fish, downstream towards the saltwater environment, where they were both re-captured, released and reported by recreational fishers.

If you are interested in learning more about the AFANT Research Fish Tagging Program or would like to register your interest to become a volunteer fish tagger, check out the page on our website.


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