terça-feira, fevereiro 07, 2017

State of World Fisheries and Aquaculture (SOFIA)

Every year FAO publishes the world fisheries and aquaculture data submitted by member states.
It is a useful source to analyse globally the state of the oceans and to understand trends regarding the seafood production and consumption.

One of the key messages from the publication SOFIA 2016 was that world aquaculture production continues to grow and now provides half of all fish for human consumption.


Source: SOFIA 2016

Pauly and Zeller (2017) just published a paper criticising FAO for reporting inaccurate data and giving wrong impressions about the seafood production overview.
Here there are some of the statements that the argue against:

1. the catch of world marine fisheries is not "stable"

We do not believe that this perceived ‘stability’ in marine fisheries catches is the case. One reason is that the catch reconstructions that have been conducted through the Sea Around Us over the last decade for all countries of the world and which will be discussed further below, indicate that since 1996, total world catches are declining at a rate of 1.2 million tonnes per year. 

...overeporting for Myanmar [demonstrated as a problem several years earlier;] is thus a clear indication as to a likely main (political) reason for the disconnect between reported data and catch reality on the ground for some of the countries of interest here. A disconnect between actual catches and official reporting of data has also been shown for China.

We thus conclude this point by suggesting that rather than stressing an elusive ‘stability’ of the world marine fisheries catch, FAO should emphasize the rather tentative nature of the trend it reports and that its apparent stability is probably a misrepresentation of true global trends due to two factors: (1) reliable catch time series that are trending downwards being compensated for by unreliable catch time series that are trending up; and (2) by the generally improving quality of data collection systems in more recent years accounting for an increasing share of actual catches without making corrections and adjustments to the under-reporting of such catches in previous years (i.e., a time-series bias), leading to inconsistent historic baselines. 


2. do not pretend that catch reconstructions does not exist

Other problems are due to a tradition that sees fish only as taxable commodities, hence only landed fish are reported, while discards are not. Thus, FAO instructs its member countries not to report discarded fish. In today's age of endorsing the Ecosystem Approach to Fisheries (as also supported and emphasized by FAO), it is anachronistic to not include discarded catches as a clearly identified category in global fisheries statistics. 


3. it is not correct to emphasise that for the first time aquaculture produced “as much as marine fisheries

...this is not correct, as fisheries catches are actually much higher than FAO reports, while aquaculture (or at least mariculture) statistics appear not to be as much miss-estimated.

More importantly, combining aquaculture statistics and capture fisheries statistics implies serious double counting will occur unless clear data adjustments are done. This is because a sizable fraction of aquaculture relies on fishmeal and fish oil or other fish products for feed in their operation. Thus, around 22% of total global fisheries landings are used for non-direct human use [33], including fishmeal and direct feed purposes.

Thus, if for example 4 t of wild caught anchovies are required as feed or fishmeal to produce one tonne of aquaculture-raised salmon, one cannot say that humanity has 5 t of fish production. Humanity has either 4 t of anchovies [which, incidentally, are excellent eating and
highly nutritious] or one tonne of salmon, but not both.


Very interesting to understand the complexity of the data that we have to analyse and take conclusions about the way we are using the resources allover the world.
Above all it is scary that per capita food fish supply (kg) is still growing together with the world population: it was 18.6 kg in 2010 and 20.1 kg in 2014!