“The most profound impact of human activity on Earth may be what we’re doing to the oceans: turning them slowly but surely more acidic. Each time we start a car, use coal- or gas-fired electricity, or travel by plane, train, or boat, half the carbon dioside emitted from the burning of the fossil fuel ends up in the sea – 25 billion tonnes …of it per year. Each molecule of carbon dioxide turns the ocean imperceptibly more acidic, in a process that is happening regardless of global warming or other changes.” (p.94)
“Corals, algae, and plankton with chalky skeletons are at the base of the marine food web. They rely on seawater saturated with carbonates and bicarbonates to form their structures, just as we use calcium to form [-p.95] our bones. As more carbon dioxide dissolves out of the air and acidity rises, however, the carbonate saturation of seawater declines, making it much harder for these animals – and indeed all shellfish – to calcify, or grow their shells and skeletons.” (pp.94-95)
“We are changing the oceans as profoundly as we are changing the air we breathe risking an important component of our future food supply – and the only known way to prevent this is for humanity to ‘decarbonize,’ to stop emitting carbon dioxide.” (p.97)
“The first and most practical thing that can be done to arrest the decline of the world’s wild fisheries is to restrict catches until the dynamics of fish populations are better understood and they can recover from what is taken. …A factor demanding urgent attention is waste: almost a quarter of all the fish caught – 25 million tonnes… per year – are thrown away. Often these are fish of low market value known as bycatch or, contemptuously, as ‘trash fish’.” (p.97)
“Fishing is an efficient industry in the sense that the fish do all the hard work of gathering nutrients for us – and we only have to gather them. so more scientific effort must be put into understanding how oceanic and local fish stocks can be renewed, perhaps by assisted breeding or redistribution, as well as by natural replenishment and the management of marine food chains. Also, because intensive aquaculture is always risky in terms of pollution or disease, greater effort is needed to pioneer extensive forms of mariculture – a kind of ‘pastoralism of the seas’ in which large marine ecosystems, entire bays, bights, and currents are manages with a view to maximising production of food in the same way that large cattle or sheep enterprises are managed in the world’s rangeland areas.
Just as humans have progressed from hunting animals to developing a food system based on farming crops over the past ten thousand uears, we need to apply similar thinking to the oceans. The growing of sea and water crops …will probably underpin an effective and sustainable aquatic harvest in the future. A huge worldwide effort is needed to devise means to efficiently grow and harvest water plants, both as food for us and feed for and land animals. Indeed, water plants are one way we can reharvest the nutrients that we nthinkingly pour into bodies of water.” (p.98)
“The ultimate power to improve the world’s fishing industries and to run pirates and plunderers off rests with the urban consumer – and so does the responsibility. Governments may regulate: consumers decide. Thus, what is needed most is worldwide education to help consumers to discriminate between fish that are produced by sustainable means and those that are obtained by mindless, greedy plundering. Have the fish in tanks in your local seafood restaurant, for example, come from well-maintained farms with a light environmental footprint, or were they caught by poor fishermen using cyanide sprayers under the direction of a ruthless and uncaring pirate company? Are pilchards more sustainable as a food choice than dories or roughies? How do you feel about eating [-p.99] a deep-sea fish that may be four times your age – and is it sustainable to do so? If you would reject a seal fur coat or whale meat, why would you not also reject unsustainable fish product? …If we do not accept that there is a problem, we will have difficulty in mustering either the will or the resources to solve it.” (pp.98-99)
What can I do about it?
“1. Eat fish sparingly and ensure that none is wasted.
2. Be an informed and selective consumer, buying fish from wild fisheries that can demonstrate that they are sustainable – that is, where the catch is balanced by natural replacement.
3. Choose grazing fish in preference to the larger predatory fish, which are needed to maintain ecosystem balance.
4. Choose farmed fish, but demand information to show that its production processes are clean, safe, and sustainable.
5. If you need more omega-3 oils in your diet, then consider algal sources or even crops enhanced to produce these. These oils originate with plant-life in any case, not with fist.
6. Support government policies that conserve water, protect its quality, and keep it free from toxic contamination so it can be used to grow fish.
7. Support all measures that will eliminate greenhouse gas emissions, to reduce the risk of ocean acidification. Reduce your own emissions.
8. If you are a fisher, practice catch-and-release.” (p.99)
Ref: Julian Cribb (c2010) The Coming Famine: the global food crisis and what we can do to avoid it. CSIRO Publishing: Collingwood, Vic., Australia.