Ecological Footprints of Intensive Shrimp Culture

The ecological impacts of industrialised shrimp aquaculture can extend far beyond the boundaries of the physical site itself. While intensive production systems are far more productive, they are far more costly to operate and are risk-prone due to high stock densities, heavy feeding rates, and the difficulty of maintaining adequate water quality and disease control. Environmental impacts are vastly greater and more pervasive in comparison to low-density operations.

The additional ecological or biophysical "costs" associated with certain aquaculture production systems has become known as the "ecological footprint". This "ecological footprint" concept seeks to quantify the minimum areas of productive ecosystem required to sustain resource inputs to and to assimilate waste outputs from the aquaculture system in question. The results of a study by Larsson and his colleagues in 1994, of a semi-intensive shrimp culture system analysed in Columbia, for instance, revealed that every "farmed" hectare

(producing about 4000 kg of shrimp/ha/year)appropriated the productive or assimilative capacity of between 38 and 189 hectares of ecosystem per year.

Larsson and his colleagues estimated that the Colombian semi-intensive shrimp farm appropriated approximately 295 joules of ecological work (i.e. natural inputs such as fish meal, agricultural products in feed and pond productivity plus industrial energy such as labour, energy to catch and produce feed, fuel, fertilizer, maintenance and harvest costs, etc)in order to produce one Joule of edible shrimp protein. In looking at industrial energy requirements alone (not including labour), shrimp aquaculture ranks high in comparison with other

production systems.

As previously stated the true costs of the ecological impacts caused by industrialised modes of shrimp aquaculture are not calculated or paid for. Indeed, if such costs of damage to the ecosystem were required to be paid, the intensive shrimp farming industry would be out of business. In their report to the Supreme Court of India, the National Environmental Engineering Research Institute (NEERI)stated that in Andhra Pradesh the industry brings in 15 billion Indian Rupees (Rs). However, the loss due to poor environment conditions caused

by it is Rs 63 billion. In Tamil Nadu, the damages totalled Rs 422 crore with the earnings only at Rs 280 crores. That is, for every one rupee gained by the shrimp farming industry in these two Indian states, as many as four are lost by the community.