Aquaculture

When you think about it, the global fish industry is peculiar in one aspect. Whereas the majority of food production has progressed to human controlled cultivation, or farms, over the last several thousand years, it would seem that fish catch is the last remaining example of mass-scale hunter gathering. After all, the mobile nature of fish means that the logical action is to gear up your boat, set sail and hope for a good catch. Increasingly however this seems to be changing.

Recent decades have seen expansion in aquaculture, an attempt to replicate terrestrial agricultural practice in the form of 'fish farms'. Typically, this is achieved through setting up nets in the sea not too far from the coast, populating them with a particular fish species and then providing required conditions and nutrients to raise them in much the way pastoral farmers have farmed livestock for millennia.

The figure below shows that at present, over half of seafood is still wild caught while 45% is sourced from farms. It is predicted that by 2030, aquaculture will dominate production with a 62% share. Many have hailed aquaculture as the solution to many existing problems with global fish harvesting, including overexploitation by humans.

Figure 1 - Global seafood consumption (Source: World Bank).

The extent to which aquaculture can be seen as the long desired fix to fisheries problems is highly contestable. One thing that is quite certain however is that aquacultural practices are likely to be affected by climate change.

A recent IPCC report (2014) pointed out that despite their seeming independence from the larger ocean ecosystem, fish farms will still experience difficulties. The food stocks for many farmed fish species are anchoveta. Declines in this pelagic fish stock will have the result of a reduced food source for aquaculture, leading to declines in output and possible price spikes.

However, unlike many advanced aquaculture technologies found in the global north, many poorer regions of the planet are reliant on ecosystem services to raise their stock. So any changes to the ecosystem at large, which have been mentioned in previous posts, will have an impact on their farms (IFAD).

Additionally, extreme weather events resulting from climate change are likely to inflict damage on coastal aquaculture projects, making it an increasingly infeasible business endeavour fraught with uncertainty and instability.

There have been attempts in recent years to carry out fish farming on land with the aid of vast tanks. However, in many cases this has proved to be too costly and the resulting waste can lead to severe eutrophication in nearby freshwater systems if disposed off improperly.

If you've been following the blog regularly, it might seem like quite a bleak forecast so far. Predictions of so many large scale disruptions in the future can seem a bit overwhelming, but from next week we'll be looking at what measures and actions can be taken to reverse or minimise climate impacts. So cheer up!