Climate Change Threatens Global Fish Stocks

New research suggests climate change could cause a massive change in the global distribution of fish stocks.

An international team, led by Dr. William Cheung of the University of East Anglia, has, for the first time, modelled the response of global fish stocks to climate change

The terrifying complexity of models such as this often makes them a tad inaccurate; however, the general trends shown by Dr. Cheung are troubling to say the least! Using 1066 species taken from the IUCN's (International Union for Conservation of Nature) Red list, the team predicts "catch potential" will increase by an average of 30-70% in northern latitudes, but to fall by 40% in the tropics.

The most vulnerable are at risk

Unfortunately, another recent publication led by Dr. Edward Alison suggests that many of the areas likely to experience a decrease are those with an already shaky food supply and (in comparison to more wealthy nations) a major dependence on fish protein⁽¹⁾. In fact the latest FAO fisheries and aquiculture report⁽²⁾ suggests Bangladesh and Cambodia (two of the countries deemed most vulnerable by Dr. Alison) get upwards of 50% of their animal protein from fish.

Perhaps the biggest worry is that many of these nations simply don't have the money, expertise and infrastructure to adapt to a change of this sort; just look at the catastrophic effect the over-exploitation of anchovies (and a subsequent El Niño) had on the Peruvian fishing industry back in the seventies.

How much do we really know?

We also have no idea how accurate Cheung's model is! There's no way to include every factor that could possibly affect the model, the researchers would go crazy and any sponsors would get a tad impatient (plus you'd end up with a slightly cumbersome, life size, fully functioning version of the entire planet).

Plus, there'll always be something completely bizarre and unpredictable to ruin even the best produced model! Lately it seems that North Atlantic Cod are evolving! They're reaching sexual maturity sooner (and at a smaller size) after excessive fishing culled the late (and larger) breeders from the gene pool.

Nobody could have predicted such rapid evolution, but it entirely throws off models used to predict sustainable fishing quotas. Now that I think about it, there's no reason other fish populations couldn't evolve just as rapidly following the massive climatic and oceanic changes we're expecting over the coming decades. So, with the added possibility of highly evolved mutant fishmen (or maybe just unexpected responses to climate change) modelling something as complicated as the ocean is a real headache. In the short term, however, unpredictability such as this makes it very easy for politicians to drag their heels whilst waiting for further information.

What can be done?

However, can we blame them? The FAO itself suggests adopting "Creative Adaptive Strategies", which I'm pretty sure means wait, see and hope like hell we can figure something out! Although this sounds crazy, at the moment it's about all that can be done! Cheung's team's research is the first of its type, scale and scope. Until we have a better idea of what to expect, large scale changes to the way we fish could be a disaster. It seems all we can do is remain aware of the science, reduce greenhouse gas emissions and support massive investment into alternative food sources.

When combined with changes to land-based agriculture, virtually all research suggests climate change is going to be disaster for global food supplies. Combine this with our ridiculous population growth, a raft of unfair international trade policies and a growing demand for meat by newly developed countries, and we might be going hungry.

⁽¹⁾Alison, E.H. et al (2009) Vulnerability of national economies to the impact of climate change on fisheries. Fish and Fisheries 10, 2:173-196

⁽²⁾Food and Agriculture Organization (FAO) (2008) The State of World Fisheries and Aquaculture (SOFIA). FAO, Rome 

⁽³⁾ The Research Council of Norway 

Published - Sun 25th Oct 2009 19:52:01