Food

As yields from captured fish are leveling out, the question

has been raised as to whether aquaculture will be able

to provide the extra fish yields needed for the world’s

expected 9.6 billion inhabitants in 2050. According to the

FAO (2013e), 62.7 million tonnes of seafood were produced

for human consumption in 2011 through aquaculture. With

an annual growth rate of 8.8 per cent between 1980 and

2010 (FAO 2012b), no other food production sector has

grown as fast in the past 40 years (UNEP 2012). Aquaculture

is gaining a dominant position within fisheries with a

40 per cent share of the total fish production (FAO 2013e)

and experts predict that aquaculture will gain an increasing

role in the global food supply (FAO 2010b).

Asia is the leading producer in the sector contributing nearly

90 per cent of all aquaculture production. Eight out of the

top 10 aquaculture producing countries are found in Asia,

with China as the main producer with 38.6 million tonnes,

followed by India, Vietnam, Indonesia and Bangladesh

(FAO 2013e). In addition to being an important contribution

to national economies, aquaculture is an important provider

of nutrient-rich food to the Asian region. The majority comes

from large-scale commercial production, but Asia also has

long traditions of fish farming for local food production.

In several Asian countries, fish is traditionally farmed

on flooded rice fields (Halwart and Gupta 2004). In fact,

developing countries are the main producers of aquaculture

with as much as 80 per cent of all aquaculture taking place in

developing countries. This highlights the sector’s importance

for economic development, poverty reduction and food

security (Asche and Khatun 2006). In Africa, aquaculture

production is still low with only 1.4 million tonnes produced

in 2011 (FAO 2013e). Scientists (Schmidt

et al.

2013) as well as

international organizations such as the FAO (Moehl

et al.

2008)

and WorldFish (2012) are promoting the potential for

aquaculture in Africa, and predict that it can play an

increasing role in supplying food for the continent.

In spite of its future prospects, aquaculture has been

criticized. Perhaps one of its most censured practices is

feeding farmed fish fishmeal made up of large proportions

of wild fish as this increases pressure on current forage fish

stocks (Naylor

et al.

2000) and their dependent species. The

ratio of wild fisheries inputs to farmed fish output is currently

0.63, though it takes about five kilogrammes of wild fish

to produce 1 kilogramme of salmon (Naylor

et al.

2009).

Fishmeal is usually made up of small pelagic fish such as

anchovies, herring, sand eels, mackerels, menhaden and

sardines (Stuart 2009). While there is no direct evidence,

there is concern that fishmeal will compete with human

food consumption, especially in regions where small

pelagic fish are important components to diets, typically in

Africa, Asia and Latin America, regions that also have the

highest number of hungry people in the world (WorldFish

2011; Tacon and Metian 2009).

Intensive aquaculture practices may also lead to

environmental degradation and changes in local

ecosystems. For example, intensive fish farming pollutes

waters with uneaten feed, fecal and metabolic waste from

the fish. This can lead to over-fertilization (eutrophication),

that can cause algal bloom and oxygen deprived dead

zones, harmful to both wild and farmed species (Schmidt

et al.

2013). When alien fish species, raised in aquaculture

systems, enter the natural habitat, either through release

or escape, these non-native fish can cause loss of native

stocks through predation, competition or transmission of

diseases (Naylor

et al.

2000).

In spite of these criticisms, many fish farms are more

environmentally friendly than other food producing

systems. For example, aquaculture has lower nitrogen and

phosphorus emissions than beef and pork. It takes 15 times

less feed to produce one kilogramme of carp compared to one

kilogramme of beef (Schmidt

et al.

2013). According to the FAO

(2011b) “responsible aquaculture can provide substantial

environmental benefits, such as recovery of depleted wild

stocks, preservation of wetlands, desalinization of sodic

lands, pest control, weed control, and agricultural and human

waste treatment”. About one-third or 20 million tonnes of all

farmed fish is produced without artificial feed (FAO 2012b).

Mussel farming relies on natural feed from the ocean and

intensive mussel farming has been shown to be beneficial

for the ecosystems as mussels filter water to sieve out tiny

particles of food, counteracting over-fertilization and algal

blooms (Schmidt

et al.

2013).

As the aquaculture sector grows, it is crucial that the

environmental and social concerns are thoroughly

addressed and that sustainable management practices

are adopted (Diana

et al.

2013). If managed sustainably,

aquaculture can be part of the solution to feeding a growing

human population as well as to restoring the dwindling

fish stocks, since increased investment in aquaculture can

potentially take the pressure off wild fish stocks, giving

them time to recover (Asche and Khatun 2006).

Aquaculture