March 2012 Article
Report confirms fish as ‘green’ protein
The New Zealand seafood industry is one that appears to be held to a higher standard than other protein producers when it comes to environmental impacts - is this fair? We examine a new report, The Environmental Cost of New Zealand Food Production that puts fi sheries ahead of dairy and meat in terms environmental impact.
The results are readily apparent, says Professor Ray Hilborn, author of the report published in February. "Wild fisheries simply do not impact the environment in the many ways that dairy and meat production do."
You would be forgiven for doing a double take at that statement says Peter Bodeker, chief executive of the New Zealand Seafood Industry Council. "If you believe anything the environmental groups say a report giving fish the green tick is likely to seem a bit out of leftfield."
But the science says it all. When considering its lower environmental impacts and pairing that with fisheries which are managed sustainably and harvested responsibly, New Zealand fish is the ‘green' protein choice.
Hilborn started thinking about the environmental cost of production around two years ago.
"Must I stop eating fish?" asked an anguished friend after reading yet another article about the sustainability of seafood. Inquiries as to what he would eat instead elicited the expected response: beef, chicken and pork, his usual ‘guilt-free dinner choices." This is the opening paragraph of Hilborn's report which posed the question - is meat indeed a ‘better' choice than fish?
Measuring environmental impacts
For this report Hilborn looked at the components that make up Life Cycle Assessments (LCAs) - a process widely used in science to determine what is required to produce, and the environmental impacts of specific products - in this case 40 g of protein from fish, meat or dairy.
LCAs measure inputs and outputs. Inputs include energy, fresh water, fertiliser, pesticides, antibiotics, surface area impacted and antifouling paints on fishing vessels. From the outset it is clear that few inputs are used in the harvesting of fish. Outputs measured are greenhouse gas emissions, eutrophication potential - this is the level of excessive nutrients in the environment - acidification potential (this can present as acid rain or soil acidification, for example), soil erosion, biodiversity impacts and solid waste and debris.
"Most of the available LCA data on farming stop at the farm gate and similarly for fishing, the available data stop at the dock," said Hilborn.
In fisheries the calculation of inputs and outputs relates to the process of the catching the fish, dominated by the use of fuel.
"None of the dynamics of the marine ecosystem are part of the calculation because the ecosystem would be there in the absence of fishing. In contrast, on a farm the environmental impacts include all the actions of the farm animals, and all the inputs into the farm, such as irrigation, animal husbandry and fertiliser application."
The biodiversity argument
When it comes to biodiversity loss New Zealand fisheries get a bad rap. The Environmental Cost of New Zealand Food Production puts this assumption to the test. Hilborn says there is a fundamental difference in how fisheries affect biodiversity as opposed to dairy and meat production.
"Fisheries rely on maintaining naturally functioning ecosystems and seek to harvest surplus biomass in a sustainable fashion."
Dairy and meat production replaces natural with exotic ecosystems. Hilborn experienced this first-hand working his own land as a farmer.
"Any agricultural area that is subject to ploughing suffers, in essence, at first 100 per cent loss of native vegetation abundance and diversity and vey high losses of dependent fauna. Where agriculture is mixed in a mosaic of farmed and more natural habitat, the change is less than 100 per cent, but for each hectare that is farmed, it is safe to assume there is very high loss most native abundance and biodiversity."
Why then, is the New Zealand seafood industry held to a higher standard than other protein producers? In the media recently, environmental organisations have criticised the report as lacking particularly around species by-catch.
Hilborn and Bodeker both have answers for this.
Hilborn says that yes, fishing does have biodiversity impacts but this, including species by-catch, is around 30 per cent - far less than agriculture.
Bodeker spells it out: "You wouldn't plough down a kiwi bird farming because there are no kiwis there - their native habitat is gone."
Should an environmentalist stop eating fish?
Should an environmentalist stop eating fish? This is a question Hilborn sought to answer in The Environmental Cost of New Zealand Food Production.
"Within the range of foods we have examined, New Zealand fisheries generally have lower environmental impacts than other forms of protein production. So the simple answer is that if the alternative to eating fish is to eat meat or dairy, someone concerned about the environment should eat fish that are captured with low fuel use - for example hoki and southern blue whiting. While we have not looked at vegetarian diets, we must remember that vegetable production requires water, fertiliser and pesticides, and causes soil erosion. Even totally organic agriculture still requires the transformation of native habitat into fields of crops, with the associated loss of biodiversity. Thus there are almost certainly trade-offs and fisheries may have less environmental impacts than a vegetarian diet."
What about aquaculture?
Sufficient specific studies on the environmental impacts of New Zealand aquaculture could not be found which was why it was not specifically included in the report, says Hilborn. However, an extensive analysis of the impacts of aquaculture was produced by the WorldFish Centre (Hall et al. 2011). They found that the environmental costs depended greatly upon the species and production technology. Species that need to be fed agricultural products or fish meal generally looked similar to more efficient livestock such as chickens and pigs. Bivalves and seaweeds place low demands on the environment and may have the lowest environmental impact of any form of food production.
The New Zealand Seafood Industry Council asked Professor Hilborn to consider the environmental impacts of New Zealand fisheries.
The report can be downloaded at www.seafoodindustry.co.nz/publications
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