Today in Western countries it is apparent to all that consumption of prawns is far greater than it was ten years ago.  Why is this?  Well, first of all, prawns are cheap and so we've lost the custom of reserving them for special occasions.  And why has the price dropped?  Simple.  Supply has increased. Yet this is not because prawns in our waters have been reproducing more than ever. What's happening is we import more and more from other parts of the world.

In the seventies, prawns began to be raised on fish farms, allowing large quantities to be obtained at a much lower price than prawns that are captured. Today, one third of world prawn production is aquacultural while two thirds is captured. The current pace of capturing and raising prawns is grossly inappropriate, for many different reasons.

Cultivated prawns

Typically, marshy coastal areas in tropical countries are mangrove swamps: forests of mangle, a tree that lives in salt water. The majority of prawn farms are established in these areas where mangrove swamps are completely cleared and turned into "pools". 

Mangrove swamps are one of the richest ecosystems on the planet.  The people who live in their vicinity obtain a variety of resources from them, including fish, reptiles, mammals, molluscs, crustaceans, birds, medicinal plants, herbs, poisons, tanning substances, spices, and wood.  When a mangrove swamp is destroyed, the source of all these resources disappears, as well as the natural habitat of these people and a part of their cultural identity.

Mangrove swamps filter sediments that travel from land to sea.  Felling them thus leaves coral reefs fronting coasts buried.  10% of global marine catches, it turns out, are obtained from these reefs.  

Mangrove swamps protect the coast from storms and hurricanes and halt erosion.  Areas least severely affected by tsunamis are ones protected by coral reefs and mangrove swamps in a good state of conservation.

The FAO estimates that since 1980, 25% of the surface area of mangrove swamps has been lost, most due to the setting up of prawn farms. 

To add new prawns to farms, larva or females with roe must be captured (although getting them to reproduce in pools is beginning to meet with success), which diminishes the amount of prawns available in the sea for local fishermen.  It has been estimated that for every larva captured, one hundred fish are killed.  

Farms generate a large quantity of organic material as waste that imbalances the marine area into which it gets drained.  Pools must be filled regularly with new water. 

Who knows what's in the feed that is fed to prawns?  Perhaps not even those who manufacture it.  What is known is that it contains fish flour, not exactly a prawn's natural diet.  Three tons of fish converted into flour are needed to produce one ton of prawns. 

The cultivation of farm-raised prawns is one of the agricultural activities that utilize the most pesticides, antibiotics, immunostimulants, etc.  Residue of all these products, none of which are healthy, can remain in the prawns.  Chlorophenicol is an antibiotic prohibited because it can cause a lethal strain of anaemia in humans but regularly used since no other form of combating some epidemics in pools presently exists. 

Fishermen must increase the amount of prawns they catch in order to be able to compete with the price of farm-raised prawns, and this leads to overexploitation of the sea.

Prawn farms eliminate fish from mangrove swamps, and therefore inhabitants of the area are left without their primary source of animal protein.  Moreover, they do not have access to prawns raised in pools because the majority is exported to countries in the North.

In the establishment of prawn farms, violence and murder have been employed to steal land; deaths have occurred in at least 11 countries.  

Prawn pools have a life span of 3 to 10 years (because antibiotic, food, salt, and other remains make them uninhabitable); in Ecuador 90% of those built are now closed.

The appearance of aquaculture in the 70s promised a salary to "poor fishermen" in coastal areas. Thirty years later, these people are discovering that with the money they earn, they are able to buy less fish than they caught before.  On top of this, fishing in the mangrove swamp is no longer an option because it no longer exists. In addition, their salary is contingent on distant factors such as the possibility that eating prawns becomes unfashionable in the West, that there is an uncontrollable epidemic (in 1999 in Ecuador a viral attack caused sales to fall by at least half), or simply that the pool is exhausted.

Caught prawns

When they are obtained directly from the sea, prawns are captured using the trawling technique: the net is dropped to the bottom and dragged, a technique which in addition to prawns also snares all kinds of marine fauna, including young, in the net.  It is estimated that with each kilogram of prawns, trawling nets also capture between 5 and 10 kilograms of other species.  All of these "extra" fish die and are thrown overboard; it is estimated that prawn fishing is responsible for a third of all fish thrown overboard in the global fishery.  It is impossible to quantify the effect of this large-scale massacre on the marine ecosystem.  

According to the FAO, it is easy to observe that many prawns are fished for in defiance of the law.

Massive fishing of prawns also deprives local fishermen of their main source of animal protein.

Furthermore, the refrigerated transport of prawns across the world, whether they are caught or farm-raised, involves a significant consumption of energy. 

All of these problematic issues are acknowledged by the FAO, the food and health organization of the United Nations, which has produced various reports regarding the situation and elaborated a code of conduct for controlling the eco-social impact of fishing for and cultivation of prawns.  The international Ramsar Convention calls for a moratorium on the opening of new farms until their impact has been evaluated more thoroughly.  All is worthless: the prawn industry continues to expand, in large part thanks to subsidies from the World Bank.

Some "usual" problems

It is not that we are especially inept when it comes to prawns; rather it involves generic aspects of our culture:

The cheaper, the better It is perhaps our most universal law.  It is why it is more of a priority to produce massively (to minimize the cost per unit) than to adjust the rhythm of production to that of ecosystems, and why things that carry an economic price such as applying measures to reduce environmental impact or properly remunerating workers are disregarded.   

By magic
We view positively the fact that as consumers we do not have to concern ourselves with what happens before products "appear" in the store, but only with having the money to buy them.  This makes us forget that in order to obtain any resource we depend inexorably on ecosystems, encouraging the use of forms of production which if known publicly would be rejected.  Also, it makes detecting signs of ecosystem exhaustion in time to avoid an irreversible situation difficult.

Direct contact with nature is scorned due to the belief that it runs counter to development (for example, having money to buy prawns is looked upon more favourably than catching them directly). It is a dogma that is applied automatically; it is not the norm to be aware that each concrete situation can be evaluated differently.

What we can do as consumers

According to Spanish professor of ecological economics Joan Martinez Alier, Consumers of farm-raised prawns that live in Europe, the United States and Japan are morally responsible for the destruction of ecosystems and human subsistence.  Naturally, all of these situations are both the cause and effect of the large amount of prawns that we consume.  

Let's go back to making prawns an item that we enjoy only on special occasions. At the same time, this will also contribute to making them truly special.      

Only buy locally caught prawns (less than a fourth of those available).

Inquire as to the manner of prawn production (many are fished industrially in Argentina) and, generally speaking, of all products.

Apply these practices both at home and in restaurants.