Fish Driven from North Sea

[Leon Roskilly]

There is indeed a thriving population of cod down in the Southwest

 

see: http://www.cefas.co.uk/fsmi/southwest%2Dcod%2Dek.htm

 

Tight Lines - leon

[Ken Davison South Wales]

Hi peterthefisherman,

 

I agree there is global warming and I would also agree that certain species are turning up earlier every year and bass have been caught throughout the year.

 

In fact that enforces my query, the cod are in the south and west including the Bristol Channel and water temperatures are definately higher.

 

I would have to take a laymans logic and state there must be some other factor involved, the facts make a complete nonsense of the report and I am amazed that those investigating have ignored them.

[Guest stevie cop]

I think there is one almighty flaw in the global warming theory.

 

If the water in, say the Thames estuary, was getting too warm for the Cod, surely they would ALL stay away? Why is it that there are still Cod here, but only a fraction of what there was? Surely if it was too warm, they'd all bugger off?

 

Cod know what temperature they need to breed successfully. You would think that they wouldn't spawn down here at all if the water was too warm. If global warming was totally to blame for the diminishing Cod stocks in the Thames estuary, then we wouldn't be catching any. Would we?

[Guest stevie cop]

One more thing. About three or four years ago we started having the worst winter Cod season's that we'd had for a long time. Yet in the Bristol channel, they were having bumper Cod seasons. If global warming was to blame for our lack of Cod, why weren't the Bristol channel Cod missing?

[Leon Roskilly]

Steve,

 

You are partly right.

 

All cod are genetically different, just like us.

 

Some of us love the warm weather, others can stand the cold.

 

If things start getting very hot, or very cold, some will stay and some will go.

 

Those who prefer things a little warmer, will have offspring that also prefer warmer conditions.

 

So, although the overall population is dangerously reduced when those who can't take the heat head north for the colder conditions there, the remaining population, who don't mind so much will eventually increase.

 

That's if the warmer weather doesn't bring increased predator activity, disease etc., which kills off the reduced population.

 

And that's why we should be very careful, fishing these populations that have been reduced by global warming, until the small pool of fish genetically inclined to favour warmer conditions can get back onto its feet and become established.

 

But I doubt that will happen. The profits of fishermen are dangerously low now. Why let good fish go?

 

And anyway cod eat prawns, and there's plenty of money to be made from nephrops now.

 

Tight Lines - leon

 

[ 13. May 2005, 09:10 PM: Message edited by: Leon Roskilly ]

[Guest stevie cop]

Leon

Is there any data anywhere which would show the water temperatures for the Thames estuary and the Bristol channel between 2000 and 2004?

[Ken Davison South Wales]

Hi Steve,

 

The MET would store that info. I do not know if you could access it though

[Leon Roskilly]

Steve Coppolo:

Leon

Is there any data anywhere which would show the water temperatures for the Thames estuary and the Bristol channel between 2000 and 2004?

For the Thames Estuary theres this:

 

http://www.cefasdirect.co.uk/monitoring/TH1.asp

 

There isn't a bouy in the Bristol Channel and the one further out (West Lunday) is inactive

 

See: http://map.cefasdirect.co.uk/smartbuoyweb/...aticMapPage.asp

 

 

But there's this:

 

http://map.cefasdirect.co.uk/smartbuoyweb/tab4.asp

 

Poke around the site and you might find more.

 

Tight Lines - leon

[wurzel]

Leon,

I am not so sure about your genetically inclined warm water cod.

I am sure that small youg cod are more tollerant, thats why we get several small fish show inshore some years but don't come back the next.

as for the water temperature off shore from the Cornish coast, it's probably colder than the shallow southern north sea, or at least more consistant,in the Thames Esturary it's only takes a change in wind direction and the temprerature jumps up or down, half the time the fish don't know weather they are comeing or going.

By being very carful fishing these populations what do you suggest? a total ban on cod fishing pahaps. As Big Cod has caught more cod than all the long line fleet from Whitby to Harwich put together recently, would he and his colleges be included in any ban?

At least I agree that fishermens profits are dangerously low.

[Jaffa]

Leon, you want to stop Nephrops fishing too?!