Open Ocean Aquaculture - Pros and Cons

Natural Marine Resources and the Economy of the Sea

Open Ocean Aquaculture Pros and Cons

Pedro Matos Pimenta - 8823

INDEX

1. Introduction

2. The fish supply challenges that mankind will face on the next decades.

3. Open Ocean - Pros and Cons

4. Solutions for the near furure

INTRODUCTION

Aquaculture is by definition the cultivation of fish and other marine species in a controlled environment, we can say that it’s a system similar to an animal farm. The three most common systems used are: - open - semiclosed - closed systems.

Open system - culture generally refers to fish farming in natural water bodies such as oceans, bays, estuaries, coastal lagoons, lakes, or rivers. Semiclosed system - are those in which the culture water makes one pass through the system and is discharged. Systems of this nature are referred to as flow-through or once-through systems. The raceway falls into this category. Closed system - are those where the water is reconditioned and recirculated to the culture unit. A more recent term for this type system is the closed recirculating system.

2. The fish supply challenges that mankind will face on the next decades.

By 2050, the Food and Agriculture Organization of the United Nations predicts that the world's population will reach 9.1 billion people. This is 34% more than it is today.To eliminate mass hunger, food supplies must grow at a faster pace, and world food production must increase by 70%. Aquaculture is vital for meeting today’s and tomorrow demand for seafood. One of the emerging system in the Open system, is the Ocean or Offshore system.

The offshore fish farms are positioned in deeper and less sheltered waters some distance away from the coast, where the cultivated fish stocks are exposed to more naturalistic living conditions with stronger ocean currents and more diverse nutrient flow. Offshore waters are deep and continually flushed by ocean currents. With no landforms to act as buffers, wave energy can be significant, especially during storm events. To withstand the force of the high seas, open water farms must be built to be more robust than those inshore, the usage of fully enclosed cages that can be tethered to the ocean floor and either mostly or fully submerged in order to protect them from waves. Several designs are in use today, either for commercial production or experimental pilot projects, and the technology is developing rapidly, aimed at reducing cost and maintenance.

3. Ocean Aquaculture Pros and Cons

CONS: - Large water flows; - Dependence on artificial rations; - Habitat encroachment and destruction; - Danger of theft - Use of antibiotics and chemicals counter disease and parasites could impact on wild populations food webs; - Transfer and spread of diseases; - Farmed fish escaping and impacting on wild populations; - Uneaten food and feces that sinks below cage can suffocate benthic organisms and change water quality; - Nets entangling wild seabirds, seals and other wildlife;

PROS:- Fish can be reared to a larger size in less time than in the wild; - Doesn’t compete for land that can be used for other food production; - Minimum space requirements - Very high production per unit area; - Lower costs than raising fish on land or in fully enclosed systems; - Provides jobs for coastal communities, especially those traditionally employed in fishing who have lost their livelihoods; - Reduces reliance on wild fish stocks; - Easy to change cages in case of contamination: - Convenience for the cultivation of many species, - Ease of collection

4. Solutions for the near furure

The use of new production technologies forecast a shift towards more technically advanced systems for high-value species of finfish between now and 2050.

One good example of investment that is being made on future approaches to offshore fish farming. Is from Norwegian shipbuilder NSK Ship Design, that created a new concept for exposed fish farming for the company Nordlaks.

Another example of future system, comes from Chile in South America. The project aims to build a low emission trimaran with 170 metres long and 64 metres wide, and it’s being developed by Ocean Ark Tech of Chile (OATECH). Ocean Ark Tech of Chile is working with Ocean Sovereign, with the goal to help feeding the earth’s growing population, in line with the UN’s 2050 Food Security Challenge. The vessel technology will be based in artificial intelligence and self-cleaning fish cages of copper will help to ensure fish health and welfare.

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