How the poor Wet hit the Daly

Global warming and overfishing. And any good news we can dig up.
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Matt Flynn
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How the poor Wet hit the Daly

Post by Matt Flynn » Thu Sep 12, 2019 4:09 pm

https://www.abc.net.au/news/2019-09-12/ ... i/11505436

This is just one missing year-class, if it rains this Wet and the bait breeds up all the other year classes are likely to be back in the river once again.

Northern rainfall is not forecast to diminish under climate change, there may be more rain in the north, so there's every chance of a good run-off and good Daly fishing in 2020.

Not to mention Million Dollar Fish now has six eligible fish for the $1m prize. Plus 100 of the $10k fish ...

So let's not get gloomy about the Daly.

The Murray/Darling on the other hand, looks f.....d.

The Daly River competition catches for 2019 and years past are in the current Aug/Sep/Oct NTMAG, fish numbers were very low this year, but it wasn't unexpected ... https://fishfinderbooks.com/fishfinders ... quarterly/
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Re: How the poor Wet hit the Daly

Post by NinjaFish » Fri Sep 13, 2019 9:59 am

Very low numbers caught and small ones at that for the SWB out at Corroboree too just recently!

I’d be surprised if we don’t get a good wet this year after a record dry (temp) that’s still going...

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Re: How the poor Wet hit the Daly

Post by Jeno » Fri Sep 13, 2019 10:02 am

here's hoping!
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Re: How the poor Wet hit the Daly

Post by wonderwobler » Sun Sep 15, 2019 2:01 pm

The fisheries research figures on the failed 2019 recruitment of Barra in the Daly is no surprise, the accompanying graph in the press release also shows low recruitment in 2006, 2007,2009,2010,2012,2013,2014,2016,2018,2019.
The researchers state it will take a number of years for fish stocks to replenish, in favorable conditions.

Meanwhile the pro catch in Anson Bay (the mouth of the river) averages 80 tonne every year, this equates to around 30.000 fish per year permanently removed from the bio mass of fish stock. This year because the fish did not come into the river and stayed in the mouth over 100 tonne was harvested...

Maths is not my strong suite, but I think if you take things away faster than you put things back, eventually it will be harder to take.

Bare in mind that the barra of the Daly are genetically wired to live in the Daly, barra from all the river systems behave this way, they don’t migrate big distances from river to river. It is possible to diminish fish stock from a particular location.

AFANT addressed this issue in 2008 with a comprehensive paper requested by the NTG.
It’s a lengthy read, it was approved and supported by the AFANT committee, many of whom still hold executive positions on the AFANT committee, and perhaps they have forgotten or lost interest in the issue.
Last edited by wonderwobler on Sun Sep 15, 2019 6:16 pm, edited 2 times in total.

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Re: How the poor Wet hit the Daly

Post by wonderwobler » Sun Sep 15, 2019 6:07 pm

Here is the AFANT submission I reference in the earlier post.

http://www.afant.com.au/blog/docs/RECRE ... YRIVER.pdf

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Re: How the poor Wet hit the Daly

Post by ronje » Mon Sep 16, 2019 7:03 am

No luck with that link

Try this one.

http://afant.com.au/archive/docs/RECREA ... YRIVER.pdf
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Re: How the poor Wet hit the Daly

Post by Matt Flynn » Mon Sep 16, 2019 12:38 pm

Here's data backing up what I said suggesting the fish will be back in the Daly next year if there is a decent wet season.

The image shows Daly Barra Nats and Barramundi Classic comp results, with big rain years generally bringing a big catch.

The few high-rain years that registered a lower catch were invariably because the comp(s) were held on a rising or steady, dirty river after late rain. The fishing fires when the river falls.

The catch trend with extra rain is obvious.

Wonderwobler notes there was poor recruitment in 2006, 2007, 2009, 2010, 2012, 2013, 2014, 2016, 2018 and 2019. This means that, roughly speaking, if the low recruitments had a major impact, there would have been poor comp catches expected three to four years later when the fish would be 50cm to 80cm long, which would be 2009, 2010, 2012, 2013, 2015, 2017, 2019, 2021 and 2022.

I can't see any match. All I see is rainfall affecting the figures. Even the poor Classic result in 2013 is offset by a tripling of the catch at the Nats in the same year, suggesting a change in the river conditions, or better tides, influenced the catch at both events.

If it rains like f...k in 2019/20 I reckon the Daly will be back online.

What is fascinating is that at the NT's Shady Camp, where the coastal barramundi gill nets were pulled out, threadfin salmon have made a huge comeback, but the barramundi appear to have not done the same. I checked the Shady Camp regional wet season rainfall over the years and could not identify any major trends.
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Re: How the poor Wet hit the Daly

Post by bigwoody » Mon Sep 16, 2019 5:16 pm

I searched for the rainfall figures for the Mary River, seems no gauging or measurements have been taken since 2001. Most of the gauging stations were closed in the 1990s. Around the time that barrages were being built to capture the water.
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Re: How the poor Wet hit the Daly

Post by Matt Flynn » Mon Sep 16, 2019 7:43 pm

I took mine from the nearest weather station I could find that had figures, which wasn't very close. Can't remember which one, might have been Middle Point.

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Re: How the poor Wet hit the Daly

Post by ronje » Tue Sep 17, 2019 7:01 am

This might help

https://nt.gov.au/environment/water/wat ... ata-portal


Map of data points.

NT Rainfall and river data points.png

Here are 2 of those purple data points (Dorisvale and Daly R police station). There are heaps more the Daly and for other river system.

Daly R Dorisvale.png
Daly R Police station.png

Jere's a plot of rainfall in Katherine 2000 - 2020
Daly Katherine 2000 to 2020.png
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Re: How the poor Wet hit the Daly

Post by Matt Flynn » Tue Sep 17, 2019 8:10 am

Great info Ron, although the one we are having trouble getting long-term data for is Shady Camp.

Nice to see no really obvious trend in the Daly rainfall graphs. I'd like to see the same thing for Daly temperatures.

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Re: How the poor Wet hit the Daly

Post by ronje » Tue Sep 17, 2019 8:51 am

Trouble with Shady Camp is that they stopped collecting data in 2012. So no data from site G8180059 since.

However, a new data station commenced in 2018 (Tyrell Branch) about 1 km away. Site 8180084.

Being only 1km away, the data should be OK for Shady Camp as well. There'll be a 6 year gap from 2012 to early 2018 but at least its some historical context.

Old Shady Camp info (pre-2013 wet)
Mary River Shady Camp.png

New info (post 2017)

Mary River Tyrell branch.png
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