A nice blog about fish and fisheries

I know I'm a lousy blogger, I'm terrible at writing, I don't do it very often and never post pictures (ok, I do post some pictures, but they're not mine). Fortunately if you like fish, this is not the only blog around!

Check this one out, it has very nice pictures and stories, mostly about Norway but also from a few other places. The blog is called A fish blog.

Enjoy!

The ironies of sustainability

I'm sure all of you have heard that eating fish is good for your health, that the omega-3 fatty acids are quite important for brain development and prevention of coronary disease, that expecting mothers are not eating enough fish and several other concerns on nutrition and public health (check this for an example). These claims are not just the 'popular knowledge' advices you'll get from grandma', there is an extense and well documented share of evidence on the subject (look at this paper published in JAMA) so it might be a wise move for you to belive it and start consuming more fish... not much of a problem, right? just change that steak or chicken breast for some tasty salmon or some juicy mackerel once in a while and you'll improve your health just by adjusting your eating habits a little bit. Things apparently work so well that it's been recommended that people in developing countries should double or even triple their fish intakes.

So, where's the catch? well, it just happens that not everyone agrees about fish oils being as nice as I just portrayed them and potential risks have been frequently listed (mercury poisoning is one of the most famous ones). Anyway, even if there are risks around the potential benefits seem to outweight them and so eating more fish still seems pretty reasonable.

"Ok, no problem then" you may say, but let's see this problem from an entirely different perspective. How many times have you heard about 'ovefishing'? (if you're reading this I guess the answer would be something like "once every two paragraphs") I think it is pretty obvious where I want to get: If we are already running out of fish and most management recommendations involve reducing catches (one way or the other) then WHERE THE HELL ARE WE GOING TO GET ALL THE FISH WE NEED? a very good question for which I have no good answer, but that's what a very interesting analysis by Dr. David Jenkins et al. published in CMAJ last month is about. Please, check it out here.

Politically incorrect joke

Ok, I'm not writing as often as I wanted to, but I can make you laugh. I found this somewhere in Facebook and thought it was pretty funny.

So it's wrong if the Japanese fish them, but it's ok if our sonars kill them?

I just found out today about this. In another wonderful display of double standards, the USA Supreme Court reversed a decision by a federal district court in California in which certain restrictions were applied to the use of sonar during military exericises. You also read the last word, right? Exercises!!! They are using sonars in a way that could harm or even cause death of several marine mammals, and they are doing it for nothing? well, exercises may be important, but are they so important that may allow the Navy to go against environmental laws? I don't think so, as does Justice Ruth Bader Ginsburg.

What is funny here is that the U.S. has been against commercial whaling since the moratorium of 1986, and has even certified Japan 3 times under the Pelly amendment. I wonder if deaths due to scientific whaling (I won't get into this debate yet) are wrong, but when they happen for "national security reasons" it's fine. Of course, there was the usual declaration of "there is no evidence...", but there is well documented evidence of deaths related to sonars for at least for one species (beaked whales), like this report says. Sonars were also supects for the death of ~400 dolphins in the coast of east Africa, and the stranding of 35 whales in North Carolina, although it was not possible to link the deaths to the sonar in the last case.

This might not be directly related to what I said I was going to talk about, but I thought I could mention it as an example on how important the environment really is for governments.

On resources tenure and stuff...

Last time I talked about the sad story of open access fisheries and said that I would do this one about resource tenure. However I'm feeling lazy now so I'll leave it for another time.

Update: Here's a small wiki entry on the subject. That should last while I write about this.

The sad story of the open access fishery

Long time without writing, don't you think so?

Today I would like to tell you another story, a sad one. Have you ever heard about open access fisheries? Maybe, but in case not I'll explain: an open access fishery is an absolutely 'democratic' fishery, one where everyone who wants to fish and has a boat can do it, without having to ask anyone for permission. It surely sounds nice and fair, natural resources should have no proprietaries and ownership should remain in the people. However, we all know that this system, though apparently fair, is almost always unsustainable and could easily result in the collapse of a fishery. This open acces situation is not exclusive to fisheries, it affects all natural resources, everywhere in the world (think for example in the deforestation of the Amazon). What might not be so obvious is why this system eventually could lead to such unpleasant results, and that's what I will try to explain.

The idea goes something like this: in an open access fishery, every fisherman can take all the fish he wants. The ammount of fish is limited and as such, the fishery can only support so many fishermen before going down into the pits of collapse, so if all the fishermen agree to catch only enough fishes to keep everything running, the fishery would sustain itself 'forever' and everyone will live "happily ever after". Of course, this doesn't happen. In the real world we have fisheries where people fish more than they should, even if they know that by doing so, they will harm everyone in the process, themselves included. This behaviour, even if it is evidently self-destructive, is quite common anywhere, and it has a reasonable explanation.

In 1968, Garrett Hardin published in Science an influential paper on this very subject titled The Tragedy of the Commons. This paper was very controversial (read it and you'll know why), but it stated clearly how the natural outcome for common access natural resources is depletion. Look, I found this comic strip which explains the idea very well:
(I took it from here)

As you can see in the pic, since individuals have no ownership of the resource, the only way they can guarantee to get a fair share is either to agree to hold resource utilization at a certain level (which, let's face it, hardly works) or to exploit it harder, since if they don't do it, someone else will do it for them. Saddest part? there is no solution for this dilemma, any open access system will eventually lead to disaster.

Bottomline, since the open access dilemma has no technical answer, we have to resort to the other option: resource ownership. It might not be "democratic" but you just saw what happens when things go "democratic". How do we do this? I'll explain it in my next post.

Fisheries management 101

Yeah, I know I said the list didn't have any particular order, but now that I think about it, why not start with the basics? I mean, if you're not a fisheries scientist, this would make your reading easier (=you will keep reading, right?). I will try to explain a few concepts that I will use over an over again. So, is the band ready?

• Fish stock:

Wow, I just started and this is already difficult. There is quite a bit of discussion on how we should define stock. My favorite definition is the one by Ray Hilborn and Carl Walters, and it says that a stock is a group of fishies that is large enough to maintain itself, and where all the little fishies have similar lives (that is, they grow at the same speed, become mature at the same age, eat the same things, like the same tv-shows, etc.). This is a very practical definition, but just because of this, it is a somewhat artificial one. Other people say that we should define stock according to a lot of genetic parameters and that stuff (the idea that we're all part of the same family), and it would be nice but it is also very difficult to establish, so I will use the one I told you before.

• Recruitment:

Ok, this one is easier. In not-so-many words, it means how many of all the baby fishies born in a given year (or any other time frame used) survive and grow up to either sexual maturity, or the age at which they are first caught (the age where they become vulnerable to fishing gear). What definition to use depends on what we want the data for.

• Spawning stock (also known as spawner stock):
  

I guess the name is quite self-explaining, right? It makes reference to the parental stock, the part of the stock who is sexually mature. So, if I say spawning stock biomass, I guess you'll know what I'm talking about... yup, that's right, it is the total weight of the spawning stock.

• Maximum sustainable yield (MSY):

This is a rather tricky concept, but it is very important to know more-or-less what it means if you want to ever grasp what is wrong with fisheries. The main idea goes like this: on one hand, the more fishies you have, the more eggs and fishies that could be born, at least theoretically. On the other, the more fishes you have, the less food there is going to be for each fish, these won't grow as large and more of them will die of starvation, so the more fish you have, the less fish you have (well, this is a little more complicated, but you get the idea). If these two things happen, then there should be some kind of theoretical optimum value where we can take the largest yield, and ensure we will keep getting such large yields into the future. If we fish more, then less fishies will be born and we will have less, but if we fish less there will be less and less food, so we won't get as many fat fishes and our yields will be smaller.

So far everything sounds perfect and we shouldn't have any problems with fisheries, but there are lots of issues with this. There's for instance, uncertainty, that is, we can never know for sure how many fishes there are in the sea, so we don't know for sure where the optimum is and how close (or far) we are from it. But there is even a bigger problem, maybe you noticed that I was mentioning the word 'theoretical', which obviously implies that we're not even sure if such an optimum value even exists! Things in nature vary just too much for us to sit and hope that they will behave the same way over and over again, that's a little bit too much optimistic. I guess you can get an idea on how some fishery managed only by using the MSY idea can easily get out of control and collapse. If you don't, you can ask me :)

• Total allowable catch (TAC):

One of the most famous concepts in this whole area of fisheries, a TAC is a quota set by the managers to the fishermen, and it states how much can be caught during a given year. There are lots of ways in which TACs are set, how they are distributed among fishermen and other things, but I won't get into it now.

• Marine protected area (MPA):
  

This is a very trendy thing these days. The idea behind it is very simple, and so far it seems to work. As its name implies, an MPA is a place where no fishing can take place, so every fish living there will be safe from us. In a way, it works the same way as a national natural park almost anywhere. There are some issues though, like for example, how do you design a reserve for species like tuna, who travel thousands of miles during their migrations? well, I will talk about that some other day.
--------------------------------------------------------

Ok, I think that is enough for now. If you know what the things above mean, you will easily understand the subject of the following discussions.

Please, let me know if you understood or not.