size limits. Who is correct?

[Jitlands]

Whilst I support size and bag limits I question the process and science that arrives at the size limits. And given the amount of our hard earned needed to fund the Qld & NSW DPI/Fisheries they should be able to substantiate the sizes imposed..

Lets say i am fishing the Broardwater and you the Tweed

I get a 75cm lizard and must let it go, You get a 75cm lizard and could keep it.

I get a 25cm whiting and kept it, you get a 25cm whiting and must let it go

I get jenny sand crabs and must release yet you could keep them

Its across the board that there is no similarities betweeen NSW and Qld regs and I question the reasoning on identical species.

Any explanations ou thoughts?

[bo_sawyer]

abit off base here (sorry Jitlands) but i always wondered what happens if you caught a flathead that could well and truly be a world record... do you still have to let it go???

[sf17fisherman]

Whilst I support size and bag limits I question the process and science that arrives at the size limits. And given the amount of our hard earned needed to fund the Qld & NSW DPI/Fisheries they should be able to substantiate the sizes imposed..

Lets say i am fishing the Broardwater and you the Tweed

I get a 75cm lizard and must let it go, You get a 75cm lizard and could keep it.

I get a 25cm whiting and kept it, you get a 25cm whiting and must let it go

I get jenny sand crabs and must release yet you could keep them

Its across the board that there is no similarities betweeen NSW and Qld regs and I question the reasoning on identical species.

Any explanations ou thoughts?

yeh i too have often wondered why in areas like this there are not shared limits and bags
however many nsw fishers do and will let a female crab go weather in berry or not as it is a smart tthing to do

one or two woun't hurt but takeing all the females just does not make sence
same goes for the larger breeded however it is a nice feeling knowing you can

[Louis]

A bit off the thread here but an interesting point to ponder nevertheless.

Are we breeding runts through our use of size limits?

Fish just like humans and other forms of animals have different rates of growth and are genetically geared to grow to different sizes.

At the moment all fishermen including both the recreational sector and the commercial sector abide by size limits.

Let us look at a possible scenario:-


Two Whiting are caught on the same day.

Both whiting are exactly the same age.

One is 23cm long and is kept.

The other is 16cm long and is thrown back into the water.

The fish that was 23cm long was a genetically larger fish than the smaller one which was returned to the water.

The 23cm fish, had he been allowed to live, may have grown to eg: 42cm

The small fish that was released would have never grown any larger than eg: 26cm.

But because the faster growing whiting was caught prior to maturity he did not get the chance to breed and pass on his genetics, or if he did get the chance to spawn it was only on one occasion.

The smaller fish however spawned many times and past on his genetics repeatedly.

If this process happens regularly over many years:


The question posed is:


Are we breeding genetically smaller fish?

Personally, I wonder if this issue has been investigated fully and whether there is something to be said for perhaps changing the size limits on certain species periodically or removal of size limits altogether on certain species periodically.





Louis

[wayne_cook]

Louis
GREAT point. Had never thought of your point sounds feasable.

Jitlands Just shows how out of tune the states are.Fisheries nsw have never come back to me with any satisfying answers to several questions I've asked.
More interested in looking at lic.

Bo-d Be prepared for a fine.

[dfox]

A simple answer to your quiery louis is "yes" of course that is the case, evidence can be found in the moreton bay sand crab fishery. A good mate of mine is a pro craber, hes in his 80's and still works. With over 50 years of experience he tells me of how the numbers are still there but over the years the size of crabs have slowly decreased, to a point that the xos crabs are nonexistant these days in the western bay.

[jpart10]

Listen mate if you really were a keen fisherman like me you would respect those laws so that future generations have the same thrill of catching a 75cm Lizzard and 25cm whiting and having a few crabs left around to catch

[onerabbit]

abit off base here (sorry Jitlands) but i always wondered what happens if you caught a flathead that could well and truly be a world record... do you still have to let it go???

Couldn't you weigh it alive & then release it , or would just being in possession, live or dead, be enough to wear the fine???

Muzz

[budge]

While your point in genetics may be feasible and agree with selection pressure laws of gentics, for many species it is highly unlikely. Supposedly the allocation of size and bag limits in current times should align with the typical size/breeding age of that particular species and therefore there shouldnt be a substantial pressure selecting in favour of a mutant size gene. Additionally with a widespread habitation of a particular species it is even more unlikely that a whole population of a particular species would be affected by the small number of mutants which would naturally occur.
It is my view though that although it is economically and culturally harder to do that these sizes should be looked at set periods much shorter than they are at the present time to take into account such trends such as the one you have suggested and many more.
It is just a personal view but i think in queensland atleast some bread and butter species like bream and whiting should have their limits increased slightly to meet a more accurate potrayal of average size of sexual maturation, also issues such as different limits for different flathead should be looked at personally i dont see why all flathead should not be at a 40cm limit as this will also help with the old i didnt know what type it was officer trick.

[Jack_Hunter]

On the topic that louis brought up, that is definately a good topic raised however it is highly unlikely that this would infact develop into a problem. If a genetically stunted fish has a reduced growth rate, other factors will also be affected, such as its vulnerability to predators, and its inability to compete for food. Because of this plus the numbers it would take for a geneticly stunted stock to outcompete and therefore replace existing stocks of fish the scenario is very unlikely.

On the example that dfox raised, the lack of xos sand crabs around no when compared to 50 years ago probably relates to the increase in fishing pressure. The probability that a crab will reach a substaintial size is greatly reduced, therefore then catching a large crab is also reduced.

I think budge hit the nail on the head when he said that the size limits of fish is generally to low, and alot of fish are not at a breeding age when they can be legally taken. This then defeats the purpose of imposing those size limits

[serene_lady]

And the sand crabs will get even smaller since fisheries brought out the notch to notch measurement of 11.5 cm. Nearly all the crabs that go 11.5 are much smaller than when they were measured 15 cm point to point. Over time the crabs will reduce in size as they go back to 11.5. And as for max size on flathead, cod, barra, and a few others because they are old breeders helps, because all the others also become old breeders when they get near there max sizes. I would say that minimum sizes are more important as there are more of them and more active at spawning. Bob.

[Leo_N.]

As Budge and Jack Hunter have mentioned, it is unlikely that genetic selection biases the population toward runts if they are based on breeding sizes.

The thing that stops fishing pressure from genetically selecting for runts is that size is the much more important than age in determining when fish become reproductively mature.

The trend that dfox mentioned with a skewed population toward undersized animals is very consistent with heavily fished populations. They seem to recover when fisheries are subsequently closed to fishing pressure.

[Jitlands]

The thing that stops fishing pressure from genetically selecting for runts is that size is the much more important than age in determining when fish become reproductively mature.



[/quote]

I agree your comments on size being more important than age for fish reaching maturity and still want to know why the NSW and QLD boffins have arrived at different sizes for the same specie. Surley this means one is wrong or both are guessing?

[bo_sawyer]

[quote author=Bo_D_ link=1142825988/0#1 date=1142827165]abit off base here (sorry Jitlands) but i always wondered what happens if you caught a flathead that could well and truly be a world record... do you still have to let it go???

Couldn't you weigh it alive & then release it , or would just being in possession, live or dead, be enough to wear the fine???

Muzz [/quote]

not sure about the rules mate, but i think it would be pretty hard keeping a flathead that size alive for long enough to go officially weigh it