Climate change & Cod fisheries

[seaside]

I'd like to suggest you download and read the following review - CLIMATE CHANGE AND SCOTTISH FISHERIES

 

http://www.marlab.ac.uk/FRS.Web/Uploads/Do...20Fisheries.pdf

 

It was conducted for the Scottish Fishermen’s Federation, a commercial organisation for those that know nothing of them whose aim is to advance the interests of Scottish fishermen at national and international levels by lobbying government officials in Edinburgh, London and Brussels.

 

The topic is the impact of climate change on fish stocks, and hence commercial fisheries and the review attempts a simple summary of some of the key findings to date.

 

It puts these into context for the Scottish fishing industry where it places some emphasis on cod, as currently changes to cod stocks in the North Sea and west of Scotland are of particular concern.

 

It was performed by the Fisheries Research Services this year and is written for fishermen, is extremly easy to read and it does challenge many pre-conceived notions and opinions.

Edited November 21, 2006 by seaside

[Jim Roper]

http://petitions.pm.gov.uk/Marine-Reserves/

[Leon Roskilly]

http://www.ices.dk/globec/data/presentations/

[ColinW]

The fishermen must have been well hacked off by those results!!

 

Executive Summary Section 8

We can not blame climate change for the decline of North Sea cod.

[glennk]

In summary, climate change has already altered many aspects of the

plankton that form the bottom of the food-chain supporting Scottish

fisheries. The oceanography of our seas has given us the most

productive areas of the European continental shelf. Climate change is

presently increasing the primary production at the bottom of the food-chain

in our area (although we can not yet predict if this increase will

continue, stop, or reverse). We can not blame a decrease in fish on a

lack of food at the base of the food-chain as a result of climate change.

Using computer models of cod growth, recruitment and fishing, the study went on to

examine in the cool and warm periods what size of cod stock was possible under

different fishing pressures. It found that the North Sea spawning cod stock, if cod

had been fished during 1988-2001 so that it produced the maximum sustainable

yield, could have been approximately 260,000 tonnes, which would have sustainably

supported a fishery during that period of 180,000 tonnes each year.

This result is very clear and worth repeating. Even given the warming in the North

Sea that happened between 1988-2001, and all the observed changes in the food-chain,

if we had fished cod at a lower level the ecosystem could possibly have sustained a spawning stock of 260,000 tonnes. In actual fact over this period the

spawning stock size decreased from 150,000 tonnes to less than 50,000 tonnes.

If we had fished cod at a lower level, the catches would have been higher. This at

first does not seem to make sense. But taking a small portion of a large stock gives

us a bigger catch than taking a large portion of a small stock. If North Sea cod had

been fished at a lower level, it could have supported a sustainable annual catch of

180,000 tonnes.

So, even with the climate changes that have occurred taken into account, the North

Sea cod population is lower than it could be, and this is a result of fishing pressure. If

the fishing pressure was reduced, the North Sea, even under current climatic

conditions, could support a larger, sustainable cod fishery and a healthy cod stock.

 

 

Using a single-species modeling approach, the North Sea, even given the

climatic conditions we have experienced since the 1980s, could presently

be supporting a sustainable cod spawning biomass of about 260,000

tonnes, which in turn could be supporting a sustainable fishery of 180,000

tonnes each year. The reason that we do not have this size of stock is

due to the high fishing pressure we have subjected the stock to. Cod is

not moving north; rather we are fishing out the southerly components of

the stock. There still remain large areas of potential habitat for North Sea

cod at suitable temperatures. We can not blame climate for the decline

of North Sea cod.

 

In the short-term, cod can recover - whichever climate change scenario was

used. If the fishery does not misreport catch, the management regime can

recover the stock to 150,000 tonnes within 6 years. If the fishery includes

misreporting, the recovery takes 15 years.

 

 

Lets hope Mr Bradshawe reads that before he goes to Brussels in December.

Edited November 21, 2006 by glennk

[big_cod]

Looks like the **** has hit the fan this time

[wurzel]

Quote

 

We can not blame climate for the decline

of North Sea cod.

 

 

Well some off us know better!

[stavey]

Quote

 

We can not blame climate for the decline

of North Sea cod.

Well some off us know better!

 

Hi wurzel did you see those old 1930's pictures of grimsby and all those huge cod!!!! thats 30 years before you thought there was not many in the north sea

[wurzel]

Hi wurzel did you see those old 1930's pictures of grimsby and all those huge cod!!!! thats 30 years before you thought there was not many in the north sea

 

Where were they caught ? probably north Norway, off Bear island or Iceland, I bet you they weren't caught locally. They defiantly weren't caught off your patch or mine.

 

Anyway I am referring to say, Yarmouth south to your bit, no doubt there were always more cod North, I should imagine Whitby has always had it's resident Cod stock. Harwich has not nor was there on your patch.

[stavey]

Where were they caught ? probably north Norway, off Bear island or Iceland, I bet you they weren't caught locally. They defiantly weren't caught off your patch or mine.

 

Anyway I am referring to say, Yarmouth south to your bit, no doubt there were always more cod North, I should imagine Whitby has always had it's resident Cod stock. Harwich has not nor was there on your patch.

 

So if i found proof of significant cod stocks say like in the biscay before 1960! what would say to that?