Talk:Atlantic cod

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[edit] North-East Atlantic Cod

I did some major changes in this article since the largest fraction of the Atlantic cod (North-East Atlantic Cod) was not present in the previous version. I also included a graph stating this point in catch terms. After the edits and additions I am however not sure where to place the sentence "The IUCN lists the species as vulnerable." Surely it does seem to apply for the North-West Atlantic Cod, but it is also true in the case of the North-East Atlantic Cod? In that case: Should the North-East Atlantic Cod be separated into two fractions? --Arnejohs 07:00, 2 May 2004 (UTC)

[edit] Cannibalism

A new contributor, DagHjermann, has provided some valuable additions concerning the North-East Atlantic cod. The following sentence may however be disputed:

The North-East Arctic Cod also shows cannibalistic behaviour, especially when there is little capelin available.

Not because of the cannibalistic behaviour, but rather the linkage to capelin. In Bogstad, B., G.R. Lilly, S. Mehl, Ó.K. Pálsson and G. Stefánsson (1994). Cannibalism and year-class strength in Atlantic cod (Gadus morhua) in Arcto-boreal ecosystems (Barents Sea, Iceland, and eastern Newfoundland). ICES Mar.Sci.Symp. 198, 576-599. the cannibalistic behaviour is verified by stomach analyses covering the time period 1949-1992. The main conclusions of this study are that cannibalism increases with predator length, most prey are less than 40 cm in length and less than 3 years old; cod eat large numbers of the young, especially those of ages 0-2 years. The frequency of occurrence of cannibalism increased with the abundance of juvenile cod (this for the Barents Sea), while there was little support for the hypothesis that the frequency of cannibalism increased when the abundance of capelin, the major prey of cod, was low. The findings of this study have been implemented in the MULTSPEC simulation model used by the Norwegian Institute of Marine Research.
Arnejohs 09:59, 4 Oct 2004 (UTC)

[edit] Size

Does not grow that large in most circumstances, usually 60-70 cms.

[edit] Red list

Source regarding Northeast Atlantic cod: [1] --Arnejohs 00:15, 22 January 2007 (UTC)

Artsdatabanken is not an official IUCN citation. Does it refer to the legally fished population in Norway's fishing grounds, rather than the north east atlantic as a whole? Do you have an English translation? Until we do, I suggest we restore the 'VU' status. http://www.iucnredlist.org/search/details.php/8784/all --Hroðulf (or Hrothulf) (Talk) 19:02, 5 October 2007 (UTC)
I restored 'VU' status for species until the article explains more about sub-populations. --Hroðulf (or Hrothulf) (Talk) 19:29, 11 October 2007 (UTC)

[edit] North-West Atlantic Cod

This explanation for the NW Atlantic Cod collapse that is "at odds with science" seems to be non-sensical to me - at least the way that it is described here is. This should be either tidied up to make more sense, or deleted. Also, there is very little useful information on the collapse of this stock - there has been plenty written and debated about this over the years, so why nothing in here?. Trevva 09:49, 29 March 2007 (UTC)

This section also includes the following sentence: "Young Atlantic Cod have become the prey in the northwest Atlantic, making recovery extremely slow as they do not spawn until about 7 years of age." There is no citation provided to support the statement that recovery has been delayed due to predation, and this sentence glosses over the numerous theories suggested for the weak or non-existent recovery of the many NW Atlantic cod stocks. In addition, the second half of the sentence ("they do not spawn until about 7 years of age") is not accurate for either Gulf of Maine or Georges Bank cod. These two cod stocks reach sexual maturity at between two and four years of age (see http://www.nefsc.noaa.gov/sos/spsyn/pg/cod/). The cause of the error seems to be in treating the several stocks in the Northwest Atlantic as a homogenous stock - they are not.Shipdriver 00:01, 5 May 2007 (UTC)

Someone who knows what they're doing (unlike myself), could you please cite the source below for the statement, "Sexual maturity is attained between ages 2 to 4" in the first paragraph and/or move it to a more relevant spot if you think it should be moved.

O’Brien, L., J. Burnett, and R. K. Mayo. 1993. Maturation of Nineteen Species of Finfish off the Northeast Coast of the United States, 1985-1990. NOAA Tech. Report. NMFS 113, 66 p. —Preceding unsigned comment added by 24.136.236.207 (talk) 02:13, August 30, 2007 (UTC)

[edit] Two taxoboxes ?

There are 2 taxonomy boxes even though there is only one species. The boxes are almost identical apart from the range (north east versus north west) and the Red List status. They even have the same picture. Should they be merged back into one box at the top of the article, similar to other species? The official IUCN Red List status is 'VU' (vulnerable) [2] - although I know that some sub-populations are quite plentiful. --Hroðulf (or Hrothulf) (Talk) 19:09, 5 October 2007 (UTC)

Done --Hroðulf (or Hrothulf) (Talk) 19:27, 11 October 2007 (UTC)

[edit] Capture of Atlantic cod 1950-2000

I just wanted to point out that the graph on the right hand side of the paragraph about capture of atlantic cod does not match the numbers stated. The number says 1,343,949 in 1956 when on the graph it shows the number somewhere around 2.5 million. —Preceding unsigned comment added by 24.57.146.172 (talk) 03:22, 19 October 2007 (UTC)

Thank you for pointing out this, the explanation is simply that the graph covers the whole Northeast Atlantic stock, while the number presented in the text refers to the North-East Arctic cod stock (in the Barents Sea). This is the major component, but during the 50-ies the catch from other Northeast Atlantic populations was considerable. The text has been updated to reflect this. --Arnejohs 22:24, 9 November 2007 (UTC)

There is another problem with this graph in my opinion. Catches of cod on the Grand Banks of Canada, which are part of the North Western Atlantic, peaked at 800 000 tonnes in 1968 before declining dramatically. However the graph shows a catch of well less than 800 000 tonnes for 1968 and no peak for that year.194.81.80.52 (talk) 13:11, 20 November 2007 (UTC)
Yes, you are right and I was wrong. Unfortunately I was mixing the catch of Europeans by European species when uploading the FAO data. The error is now corrected and the changes are substantial. I can nothing but apologise for the error I brought to this article. Thank you very much for pointing out the error. --Arnejohs (talk) 14:09, 20 November 2007 (UTC)