Jump to content

NSW slot limits


Recommended Posts

13 hours ago, Daryl McPhee said:

Mid-sized females (45 cm - 69 cm TL) dominate the production of eggs due to their abundance in the spawning aggregation

This would be right in the slot limit - So am i reading this extract right that the science doesn't quite back up the slot limits? With older / larger Female Flatties not really in the spawning aggregation?

Link to comment
Share on other sites

19 hours ago, Daryl McPhee said:

Here is a summary some published information from a colleague Dr Barry Pollock. 

The annual spawning aggregation of dusky flathead 'Platycephalus fuscus' at Jumpinpin, Queensland

Dusky flathead 'Platycephalus fuscus' form seasonal spawning aggregations where estuaries meet the ocean in eastern Australia. The present study at Jumpinpin in south Queensland shows that dusky flathead have a protracted spawning period with serial spawning during summer (November to April). They are rudimentary hermaphrodites with sex determined at an early juvenile stage. Sex ratios are skewed with males most common in the smaller size-classes (< 50 cm TL). Mid-sized females (45 cm - 69 cm TL) dominate the production of eggs due to their abundance in the spawning aggregation. Within the female component of the spawning aggregation, the occurrence of individuals exceeding the current maximum size limit of 75 cm TL is low (2.6%). Parasitic nematodes (philometrids) occurred in 8% of ovaries. Degenerated ovaries, in which atretic oocytes are common, are present in half of the very large females (70 cm - 75cm TL) examined. The current minimum size restriction of 40 cm TL for dusky flathead provides protection for 73% of males and 15% of females within the spawning aggregation. 

Bloody legend Dazza. Thanks

Link to comment
Share on other sites

29 minutes ago, Andrew_P said:

Slot limits may be used to protect certain parts of fish population (ie big Barra) biologically but may also be a reflection of fisher behaviour (eg fishers considering big flathead too precious to keep/kill)

I’m good with this, as I think everyone on this forum would be. It also means future generations can also enjoy the thrills of catching and releasing a large specimen or devastation of getting busted off by a freight train.

Link to comment
Share on other sites

There is some work specifically in NSW. This is not work that I have been associated with, but the Abstract is below and the full text can be accessed here: Oogenesis, Oocyte Atresia, Ovarian Development and Reproductive Senescence in the Dusky Flathead Platycephalus fuscus (Teleostei) (escientificpublishers.com)

Abstract
The aim of the present study is to examine developmental changes of oocytes and ovaries of a wild population of dusky flathead Platycephalus fuscus (Cuvier, 1829). This fish is endemic to the east coast of Australia where it inhabits estuaries and coastal waters. It is extensively fished throughout its range. It is a serial spawning teleost, capable of producing vast numbers of externally fertilised eggs in batches over a protracted annual spawning period. Successful egg production, as indicated by the presence of hydrated oocytes and post ovulatory follicles, is commonly observed in small and mid-size females (35cm–65cm Total Length; 2-6 years old) which numerically dominate the female component of the spawning aggregation. Oocyte atresia, at various levels, commences at the vitellogenic oocyte stage, and occurs in all mature fish during the spawning period. Mass oocyte atresia and degenerate ovaries were commonly observed in large fish (>70 cm Total Length and 7 years old), indicating that reproductive senescence occurs after females reach this size.

 

Link to comment
Share on other sites

On 20/06/2022 at 12:16 PM, Junky said:

Good on NSW. 

 

I'm not sure on size and bags effectiveness either.

It saved them from extinction, that's for sure but I would have thought for a fish so easy to catch that their numbers would still be dropping, even with the current size and bag quotas. 

I hope I am wrong. 

No saltwater fish has ever been fished to extinction. Also we have the 30 rec havens in our favour.

Link to comment
Share on other sites

On 23/06/2022 at 9:57 AM, Hweebe said:

This would be right in the slot limit - So am i reading this extract right that the science doesn't quite back up the slot limits? With older / larger Female Flatties not really in the spawning aggregation?

Remember the bag limit has been halved as well.

Link to comment
Share on other sites

  • 9 months later...
15 hours ago, Phil712z said:

They went pretty close to it with the collapse of the Atlantic cod fishery in the Grand Banks in Canada in the early 90's. In 1992 the cod population fell to 1% of historical levels, due mainly to decades of overfishing. Despite a ban on cod fishing being put in place, thirty years later the cod population has still nor recovered to a level where it can be sustainably fished.

I don't think the numbers of dusky flathead were even dropping as you suggested. The latest restriction were actually the result of lobbying by anglers. 

Link to comment
Share on other sites

  • 1 month later...
On 08/04/2023 at 2:56 PM, bigkingie said:

I don't think the numbers of dusky flathead were even dropping as you suggested. The latest restriction were actually the result of lobbying by anglers. 

I didn't suggest the numbers of dusky flathead were dropping. I was just pointing out that there has been a case of a saltwater fish nearly being fished to extinction. In Canada the cod stocks were reduced to such a low level that even with a total fishing ban being put in place the remaining cod struggled to rebuild their numbers because of the toll that was still taken by natural predation.

 

Link to comment
Share on other sites

Join the conversation

You can post now and register later. If you have an account, sign in now to post with your account.

Guest
Reply to this topic...

×   Pasted as rich text.   Paste as plain text instead

  Only 75 emoji are allowed.

×   Your link has been automatically embedded.   Display as a link instead

×   Your previous content has been restored.   Clear editor

×   You cannot paste images directly. Upload or insert images from URL.

×
×
  • Create New...