Thu Feb 24, 2005 9:25 pm

Fish don't change in 50 years. Perhaps you would like to explain the mutation in the Barbels barbel caused by the growth promoters in pork luncheon meat. That's come about in less than 50 years.

The thing missing from your equation is MAN and his impact on everything he touches. I find it laughable that you wave a non existent Bsc, to support a flawed argument. A piece of advice given to me by my principal
"Engage brain before you put pen to paper.". :idea:

"What experience and history teach is this. That people and governments have never learned anything, from history, or acted upon any lessons they might have drawn from it." George Wilhelm Friedrich Hegel..

verbum sat sapienti......... :D as we say in Middle Earth 8) .....

Fri Feb 25, 2005 10:44 am

this is starting to get annoying, i'm not saying your wrong, i'm not disagreeing with the fact that fish seem to be getting smaller, i'm in total support of saving fish, and putting them back. i'm not disputing the fact man is what is screwing fish species, all i'm saying is that i find it near impossible to believe that through netting of fish over 50 years, has caused a genetic mutation. factors such as heavy metal traces, changes in pH, increased silting of estuaries, all these are directly linked to human activity, and thats why i choose to this this poxy degree to start with, so i could try, and make a difference.
i'm in total agreement with with you on the barbel, but once again it can't be compared to netting. it's a chemical inbalalance within the fish caused by the artificial introduction of growth stimulants into the fishes diet..... expose a human to a life time of low level radiation, or mercury, we get all sorts of tumours, and diseases withion our lifetime. in comparison reduce the size of every door way on the earth by half, so we have to stop, and crawl through the gap, rather than stroll or run through. we as a species aren't going to reduce in size in 50, 100, or 500 years. there is a difference between physical, and chemical changes.
yes i'm aware we are much larger than most fish, but we are similar in structure in that we are invertebrates. we are closer related to fish, than fish are to daisies!!
ok this thread has gotten close to 500 hits, does any one at all out there have any understanding of what i'm trying to say?

Fri Feb 25, 2005 11:18 am

Go Frodo, I'm with you on this one.

Fri Feb 25, 2005 11:41 am

As one of the 500 plus hitters on this thread I love it. In the red corner the, almost, a scientist and in the blue corner the philosopher :lol: . Frodo I am inclined to agree with your main point that fifty years is too short a time for genetic mutations, due to changes in the physical environment, to appear. However, your point is somewhat lost by your lack of tact and subtlety in presenting it. I am speaking here, by the way, as one who has a dominant tactless gene :lol: .

In an earlier post you equated having degree to having expertise. Well in my experience your degree is what will get you an interview and help you negotiate a better salary. Expertise, however, is gained from your time in the real world working in your chosen field. In fact this experience will no doubt help you on that road. A valid point can be very easily lost by inappropriate presention e.g. standing on the rock of an soon to be had qualification and beying to the world (whoops, there is my lack of tact breaking through :lol: ). Think Socrates, who, instead of beating people around the head with the answer, asked them questions. At the end of a series of questions his audience answered the question for themselves.

Finally I just remembered a fact that I came across a few years ago. Apparently in France the average size of French men was below the European average ( my apologies for not being able to cite my reference). This was due to Napoleon placing the big guys at the front of his army in order to frighten the enemy. Unfortunately, because they all tended to die, he in effect manage to decimate the 'tall man gene'. Could this happen to fish when we
"Throw back the little ones
And pan fry the big ones"

A quick thank you to all for helping me find my latest signature quotation. And finally Jack
verbum sat sapienti
I love it and my word is ....... diatribe :lol: :lol: :lol: .
Last edited by Read on Fri Feb 25, 2005 12:27 pm, edited 1 time in total.

Fri Feb 25, 2005 12:13 pm

thank you that's all i wanted.....just someone who knew what i was ranting on about!

Fri Feb 25, 2005 12:33 pm

neil with all this scientific talk surely u and ur mice must get a mention somwhere!!!!!

Fri Feb 25, 2005 10:10 pm

It's just this, in the 60's we had a caravan @ caistor-on -Sea. Gt Yarmouth was the place it all happened. You could in actual fact, walk from one side of the Harbour to the other without getting your pinkies wet on the decks of Trawlers. Steam trains pulled wagons of wet fish across the promenade.
Now all there is in the harbour is what.... June 1994 it was empty.........

'vox et preaterea nihil'

Sat Feb 26, 2005 2:48 am

Hope this inny Gaelic cos I dunny talk it. lolol :D :D

Decreasing fish sizes

Sat Feb 26, 2005 11:26 am

The post above regarding Napoleon and short Frenchmen has, in my view, hit the nail on the head. It is, of course, nonsense to suggest that spontaneous genetic mutation could have occurred and become ubiquitous over a time-frame of 50 years, allowing fish species to evolve into smaller versions in order to avoid capture. What the report actually suggests is that, as larger fish are more likely to be caught in nets, the balance of the population shifts to favour the smaller fish (which already have the "small" gene). As such, more genetically small fish breed and reproduce than genetically large ones so, over a number of (fish) generations, the average fish size will decrease. It's Darwin's principle of survival of the fittest, and can happen quite rapidly when a sudden change in the environment occurs, such as the current explosion in commercial fishing.
Of course, its not quite as simple as that, which is the point that I think Froddo was trying to make. A lot of the small fish that escape the nets are simply the juveniles of large fish, and many of these will also get the chance to breed before they are caught. However, the basis of the argument is sound - average fish sizes will decrease as a result of over-exploitation. Then again, we all knew that already, didn't we!

Re: Decreasing fish sizes

Sun Feb 27, 2005 8:51 am

" It is, of course, nonsense to suggest that spontaneous genetic mutation could have occurred and become ubiquitous over a time-frame of 50 years, "

Spontaneous, Resulting from natural impulse, NOT FORCED or suggested or caused from OUTSIDE, instinctive or automatic, volunteered or unconstrained.

So growth promoters in Pigs, have nothing whatsoever to do with the genetic mutation of the Barbel. It doesn't take the brains of Einstein, to know that all things being equal it will take millions of years to evolve naturally. What I'm saying is this that mans interference is an OUTSIDE FORCE and is not natural.

I also think that you are understating the 'Wild Card' in genetic mutation.
Try asking the Trilobite.......................

Mon Feb 28, 2005 2:37 pm

That's interesting about Napoleon, i'm French myself and the story I had heard was that there was increased agricultural mechanisation in the mid 19th century, people's revenue increased and they started to drink much more. A lot of kids would have started working in the fields or in factories from the age of 12 or younger and drink to keep going through the long working hours. It could have been a combination of two factors, just like fish: survival of the smallest and unhealthy stuff hampering growth

Mon Feb 28, 2005 4:28 pm


I tried, but failed, to find any study relating to barbel, pork England etc., Though I do not doubt it happened I believe the jump from a local case of change in a species, probably due to chemicals, to a global change due to a physical constraint, a bit much. Even relating my tale of the French to changes in fish size is a bit loose if only because the natural progression from small to big being interrupted doesn't mean the potential for big is excluded.

I checked your latin quotation, not being a native speaker I used Google, and it appears to be mispelt. If you meant 'vox et praeterea nihil' then perhaps you should check your spelling when firing such bullets :wink: .

Mon Feb 28, 2005 8:13 pm


So I made a typo 'A' before the 'E' instead of 'E' before the 'A'.

"errare est humanum"

If fish evolve over millions of years. What went wrong with the 'COELACANTH'.

Like I said you take no account of the wild card in genetics. What ever happened to Neanderthal man. Here one minute gone the next :)

Tue Mar 01, 2005 10:21 am

yes, genetic wild cards, but you are standing by a paper that claims ALL fish species have suddenly stopped growing in a bid to survive. coelacanth, and trilobite are just that, freaks, one in a million. but for suddenly the vast majority of viable commercial fish along with unwanted by catchs to stop growing due to human constraints, that indeed would be one of humanities greatest triumphs over it's arch enemy, mother nature!!
i'm sorry, it just comes down to alot of these reports prsenting facts in a certain light, they are not neccessarily lying, just bending the truth

Tue Mar 01, 2005 11:15 am


I generally have no issue with spelling and typo's. This particular case struck me as a high brow jibe which I thought was unwarranted and so I took you to task with what I hope was a light touch :) .

In the case of my tale of the French wouldn't Napoleon be a wildcard? With regard to the Neanderthals, my understanding is that they disappeared over several millennia because of competition from the newly arrived homo erectus or because of climate change (or possibly a combination of both). In the context of what is being discusssed in this thread the point is that no one is quite sure why they disappeared. This brings me nicely to my main point in this post.

I reviewed the posts again to see what was in dispute here and it appears, to me, to distill down to certainty. As I understand science it is based on hypothesis, our best theory so far that explains the facts. The level of certainty varies from speculation to a high degree of certainty. For example the barbel case you cited sounds to me like a high degree of certainty could be established. It is a relatively localised environment with relatively low complexity and an overwhelming unnatural intervention. However the general case of genetic change in all fish must have a much lower level of certainty when you consider the multitudes of environments, the huge complexity involved with the sheer number of other 'wildcards'.

So while I wouldn't be surprised to see what you are describing to be a major cause of genetic change I wouldn't be betting my house on it, especially not so when the time frame involved is so short.