tag:blogger.com,1999:blog-22424144.post116649124188541817..comments2023-11-02T04:18:45.711-07:00Comments on blogfish: Are big fish disappearing or not?Mark Powellhttp://www.blogger.com/profile/08121566220326246265noreply@blogger.comBlogger8125tag:blogger.com,1999:blog-22424144.post-1166772805356706532006-12-21T23:33:00.000-08:002006-12-21T23:33:00.000-08:00Ah, but it's so much easier to criticize others th...Ah, but it's so much easier to criticize others than to come up with a good solution of one's own.<BR/><BR/>I think we have a disconnect in our single-species management system where reference points which are intended to be proxies for MSY, if applied properly to the least productive species, would lead to a level of fishing in multi-species fisheries well below the maximum sustainable yield forAnonymousnoreply@blogger.comtag:blogger.com,1999:blog-22424144.post-1166643156607627822006-12-20T11:32:00.000-08:002006-12-20T11:32:00.000-08:00Ian,Great comments and questions, thanks! If look...Ian,<BR/><BR/>Great comments and questions, thanks! <BR/><BR/>If looking only at single-species management, I think it would be fine (probably appropriate) to maximize yield outside of reserves if an ideal reserve network existed and it protected population structure, geographic range, and avoided loss of minor population segments (the latter hard to measure, so let's have range as a surrogate Mark Powellhttps://www.blogger.com/profile/10333424116503463839noreply@blogger.comtag:blogger.com,1999:blog-22424144.post-1166641471147153492006-12-20T11:04:00.000-08:002006-12-20T11:04:00.000-08:00You often focus on the elimination of big fish and...You often focus on the elimination of big fish and the reduced geographic range of fish populations, and the need to include these factors in our assessment models <BR/><BR/>But what happens if we get it all these details worked out for a given species and come up with an ideal management plan for that species. Perhaps it would includes a network of marine reserves covering 20% of all habitat Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-22424144.post-1166589278425879652006-12-19T20:34:00.000-08:002006-12-19T20:34:00.000-08:00Tim,Now we're really getting somewhere. The Good ...Tim,<BR/><BR/>Now we're really getting somewhere. <BR/><BR/>The Good Depletion is the planned depletion of fish populations to 20-40% of their unfished biomass, based on an outdated belief that this is good management. We have much evidence of neglected problems in the outdated models that predict this is a good idea. <BR/><BR/>It's true that fishing takes fish out of the ocean, so some Mark Powellhttps://www.blogger.com/profile/10333424116503463839noreply@blogger.comtag:blogger.com,1999:blog-22424144.post-1166567285381663302006-12-19T14:28:00.000-08:002006-12-19T14:28:00.000-08:00I'm not sure what you mean by the "good depletion"...I'm not sure what you mean by the "good depletion" Mark. If it means what I think it means, then I'd be the first to point out that surplus production theory is not the ultimate answer to everything. However, it surely has to be admitted that you can't have any "production" at all without at least some "depletion", unless you start transcending the limits that the ecosystem puts on your "Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-22424144.post-1166545721980135322006-12-19T08:28:00.000-08:002006-12-19T08:28:00.000-08:00Thanks Tim,The "self-referential" bit refers to th...Thanks Tim,<BR/><BR/>The "self-referential" bit refers to the soundbite saying that these issues are too complex for soundbites. <BR/><BR/>I think we have some scientific disagreements amongst us, I think there is doubt absout the standard view that "THE GOOD DEPLETION" really works perfectly all of the time everywhere. Some species don't fit the theory, and there are extra factors not includedMark Powellhttps://www.blogger.com/profile/10333424116503463839noreply@blogger.comtag:blogger.com,1999:blog-22424144.post-1166517717071012442006-12-19T00:42:00.000-08:002006-12-19T00:42:00.000-08:00This comment has been removed by a blog administrator.Anonymousnoreply@blogger.comtag:blogger.com,1999:blog-22424144.post-1166517671142638322006-12-19T00:41:00.000-08:002006-12-19T00:41:00.000-08:00Although I'm inclined to leap to the defence of my...Although I'm inclined to leap to the defence of my colleagues, and to argue with you over things like your implication that the phrase "cherry-picked data" is self-referential, and your definition of "large fish" (which has to be more restricted than other definitions in order to make your point), I would rather draw attention to the fact that you have hit the nail precisely on the head (sorry Anonymousnoreply@blogger.com