Something fishy
Posted 14th November 2007 at 01:56 PM by hampel
The controversy surrounding the Namibian midwater fishery, which mainly targets horse mackerel, comes as no surprise.
Rumors have been rife for some time now on illegal fishing activities inside the 200m depth zone - mainly on the northern fishing grounds - as well as on the open-ocean transfer of catches, and the alleged (which is now being investigated) dumping of unwanted catches.
And then, amidst the chaos this important fishery has been drowning in the last two weeks, one of the vessels that had been recalled to WBay decided to make a run for it, which does not necessarily count in favor of the industry either.
Now of course the industry bemoans the daily loss of millions of N$ due to the recall, and the vessels crews suffering the brunt of it, consequently increasing the frustration among the stakeholders.
But stop there for a moment and consider the implications of any of these rumours on the fishery(and its future health)? The horse mackerel stock is assessed annually, and this assessment takes into consideration annual scientific biomass estimates, total annual catches, and a range of biological data.
Scientist from MFMR then analyze this data, trying to observe trends in the data, or explain the difference between annual catches and annual observed biomass, eventually coming up with the magic number (or a range), which forms the basis of a quota recommendation.
Problems arise when the input data is full of snags and thus the resulting output close to useless (if not dangerously wrong). If the annual catches are in fact much higher than reported (due to fish dumped or transshipped - unreported catch), the average length of a caught horse mackerel much lower (due to small fish being dumped but not recorded), and the estimated mortality of the stock much higher (observed length data giving wrong signals), the assessment would churn out very different figures.
Actually this 'bad information' would result in the health of the stock (the current biomass swimming around in the sea) being overestimated, and the quota recommendation being way to high. The green light is given for catching fish which is not really there.
Therefore, assuming hat there might be some truth to the allegations against these vessels, and considering the possible consequences of inaction, I fully support the actions taken by the government to investigate this matter to the fullest.
Rumors have been rife for some time now on illegal fishing activities inside the 200m depth zone - mainly on the northern fishing grounds - as well as on the open-ocean transfer of catches, and the alleged (which is now being investigated) dumping of unwanted catches.
And then, amidst the chaos this important fishery has been drowning in the last two weeks, one of the vessels that had been recalled to WBay decided to make a run for it, which does not necessarily count in favor of the industry either.
Now of course the industry bemoans the daily loss of millions of N$ due to the recall, and the vessels crews suffering the brunt of it, consequently increasing the frustration among the stakeholders.
But stop there for a moment and consider the implications of any of these rumours on the fishery(and its future health)? The horse mackerel stock is assessed annually, and this assessment takes into consideration annual scientific biomass estimates, total annual catches, and a range of biological data.
Scientist from MFMR then analyze this data, trying to observe trends in the data, or explain the difference between annual catches and annual observed biomass, eventually coming up with the magic number (or a range), which forms the basis of a quota recommendation.
Problems arise when the input data is full of snags and thus the resulting output close to useless (if not dangerously wrong). If the annual catches are in fact much higher than reported (due to fish dumped or transshipped - unreported catch), the average length of a caught horse mackerel much lower (due to small fish being dumped but not recorded), and the estimated mortality of the stock much higher (observed length data giving wrong signals), the assessment would churn out very different figures.
Actually this 'bad information' would result in the health of the stock (the current biomass swimming around in the sea) being overestimated, and the quota recommendation being way to high. The green light is given for catching fish which is not really there.
Therefore, assuming hat there might be some truth to the allegations against these vessels, and considering the possible consequences of inaction, I fully support the actions taken by the government to investigate this matter to the fullest.
Total Comments 3
Comments
-
Very interesting, Hampel. What do you think can be done to make sure our fish stocks are made sustainable in the long run, and to prevent them from being plundered?Posted 16th November 2007 at 02:28 PM by Comrade_007
-
Last week cabinet approved a reduction in the total allowable catch (TAC) of horse mackerel (hm) and rock lobster. Judging by newspaper reports this is based on a reduction in biomass and catches, and in the case of hm smaller fish caught.
The cabinet decision is likely to be a blow to the fishing industry, but a life line for the resources.
The TACs for the other commercially important species, like hake, monk, and to a lesser degree pilchard, will only be decided on next year. So what can be done to ensure the sustainability of marine resources in general?
Managing any marine resource on a sustainable level must be one of the most difficult endeavors. Why?
Well, look at it this way.
1) The environment these organisms occupy is not entirely static, meaning it changes on a temporal, for instance seasonally or sometimes even daily, and spatial level. Organisms respond to these changes either in a determined way, by for example going to specific places every year to spawn or reproduce, or in a more haphazard way, for instance in search of food. Consider now that marine scientist go out on a research boat to collect data on the abundance of horse mackerel (hm), they need to have some idea where hm occurs (because ships time is expensive, one doesn't want to spend much to on searching), at which time of the year they are most concentrated, or what the possible potholes can be when determining how much of hm there is.
Which brings me to point 2). In 90% of these research surveys the organisms investigated are not observed directly but rather indirectly, - what I mean by this is that its not like going into a forest and counting tress, but more like looking at the forest using satellite pictures and trying to find out how many trees there are. There is always a degree of imprecision, and the trick is to reduce this.
So we know that assessing how much hm there is out there is tricky, but can be done with some degree of confidence.
Knowing this is not enough though! In addition one needs to know how much hm was caught, what size was caught, whether the environment has changed and how it might have influenced the health of the hm population, how much young fish were produced etc etc.
Then there has to be compliance by the industry, i.e. no dumping, transfer, illegal fishing practices like small mesh sizes etc. etc., and lastly the resource has to be protected from pirate fishing (boats which are no registered in NAM), often committed by companies from nations with over-bloated fishing fleets.
Is the NAM government doing enough regarding sustainable management? I think to a large degree it is. It spends a good deal of money on annual research surveys and assessing fish stocks, the enforcement of rules and regulations (either via observers on board the fishing vessels or via patrol vessels), and tries to keep pirates at bay. But the ocean is big and vital resource at times scarce.
To improve matters more focus needs to be put on understanding the interaction between a changing environment and marine organisms, as well as interactions between organisms. AND, the fishing industry needs to realize the responsibility it has towards sustainable fisheries. A high TAC today is not always good news for the fishery of tomorrow.Posted 22nd November 2007 at 09:52 AM by hampel -
Thank you Hampel for an excellent post! Very interesting reading. You must be an expert in your field. There is an excellent article here that underlines some of your points: http://www.theshebeen.org/economy/40....html#post4258Posted 24th November 2007 at 11:07 PM by Shebeen
Total Trackbacks 0
