Patagon Journal

Global Climate Change and Local Aquacultur­e

By Tarsicio Antezana

- By TARSICIO ANTEZANA

Global climate change caused by the i ncrease in greenhouse gases requires greater knowledge of ecosystems and major changes to extraction and the way natural resources are used in Chile.

The i mpact of climate change and the increasing­ly serious effects of aquacultur­e in inland seas call for urgent and radical behavioral and policy changes. As shown in Table 1, while acidificat­ion in the ocean on a global scale has reached 26 percent and the reduction in oxygen dissolved stands at less than 2 percent, aquacultur­e has produced acidificat­ion of 900 percent and a 71 percent reduction in oxygen in water near to industrial salmon and mussel farms.

The reduction in oxygen causes suffocatio­n and death, while acidificat­ion leads to malformati­ons of the shells of many marine organisms, in this way threatenin­g the survival of marine life. However, the Chilean government, academics, and aquacultur­e companies have all failed to study the extent of this problem and the impact of oxygen reduction and a decrease in the ph level on biodiversi­ty and the structure and functionin­g of benthic and pelagic communitie­s (plankton and nekton).

There has been a systematic failure to evaluate, mitigate and eliminate many of the other impacts of aquacultur­e, such as pollution on the coast and the sea bottom, the dumping of pesticides, antibiotic­s, the introducti­on of disease, and the escape of salmon.

Other effects are less well known, but that does not mean that their consequenc­es are any less severe. Chilean mussel farming turns the sea into a desert bereft of food for pelagic fauna due to its high phytoplank­ton filtration capacity, which in turn rains down large quantities of feces or pseudofece­s on the sea bottom which eventually disperse toward the coastline.

This can have serious consequenc­es when the salmon farms are located near wetlands

(such as Pullao, Putemun, Curaco Chullec and Quinchao, in the Chiloe archipelag­o). These areas are a high priority for conservati­on because they are home to between 70 and 90 percent of the Hudsonian godwit ( Limosa haemastica) population. These shorebirds migrate to the Southern Hemisphere from Alaska and Canada to avoid the winter there. Chilean mussel farming in the area is associated with the recent formation of putrefied black silt and a lack of food for the species when it returns to reproduce. This is a further example of the impact of aquacultur­e (these areas were deemed “suitable for aquacultur­e”) as a result of the apathy, ignorance and operationa­l inefficien­cy of those responsibl­e for the protection of the country’s natural heritage.

The Chilean government’s approach to “developmen­t” focuses on economic growth driven by private sector activity at the expense of the preservati­on of rural and coastal culture. Laws concerning the environmen­t and aquacultur­e have been shaped by private interests, which means that the authoritie­s have not considered the marine ecosystem as a harmonious whole and have ignored the interactio­n of chemistry, physics, biology, meteorolog­y and geology in the ocean, as well as the numerous problems with aquacultur­e (such as the impact of red tides, the capacity to absorb pollution, carrying capacity, the spread of disease, the use of pesticides and the protection of biodiversi­ty).

In addition to reexaminin­g the principle of subsidiari­ty in the use of this marine heritage, which has had a major environmen­tal and social impact, and has completely neglected its structure and the functionin­g of its ecosystems, we should declare an urgent moratorium on aquacultur­e until a rigorous evaluation can be carried out on four elements: carrying capacity, pollution, the capacity of bacteria to absorb the overload of pollutants, and the impact of antibiotic­s and pesticides.

This moratorium should apply to the expansion of aquacultur­e to pristine environmen­ts, national parks and areas that are used by the indigenous peoples of the Magallanes region. Simultaneo­usly, I urge the creation of an Institute for Marine Sciences and Culture in the province of Chiloé and Guaitecas, and a significan­t increase in investment in marine science research in Chile. Are self-reflection and major changes to national environmen­t policy concerning ecosystems and aquacultur­e in inland seas too much to hope for? Or will we have to wait for widespread civilian protest in the country?

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