# World Aquaculture: Environmental Impacts and Troubleshooting

Authors: Marcel Martinez-Porchas; Luis R. Martinez-Cordova
Journal: The Scientific World Journal
 (2012)

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## Abstract

Aquaculture has been considered as an option to cope with the world food demand.
However, criticisms have arisen around aquaculture, most of them related to the
destruction of ecosystems such as mangrove forest to construct aquaculture
farms, as well as the environmental impacts of the effluents on the receiving
ecosystems. The inherent benefits of aquaculture such as massive food production
and economical profits have led the scientific community to seek for diverse
strategies to minimize the negative impacts, rather than just prohibiting the
activity. Aquaculture is a possible panacea, but at present is also responsible
for diverse problems related with the environmental health; however the new
strategies proposed during the last decade have proven that it is possible to
achieve a sustainable aquaculture, but such strategies should be supported and
proclaimed by the different federal environmental agencies from all countries.
Additionally there is an urgent need to improve legislation and regulation for
aquaculture. Only under such scenario, aquaculture will be a sustainable
practice.


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## Body

## 1. Introduction

Aquaculture, the farming of aquatic organisms, has been the agroindustrial activity
with the highest growth rate worldwide in the last four decades. From 1970 to 2008
the production of aquaculture organisms grew at a rate of 8.3% per year,
compared to less than 2% of fisheries, and 2.9% of livestock [1]. The annual aquaculture production is at
present over 60 million tons (including marine plants), with an approximate value of
85 billion dollars [2]. The last FAO report
revealed that the world population increased by 6.3% from 2004 to 2009, whereas
the production of aquatic organisms by aquaculture increased by 31.5% in the
same period (Figure 1) [2].Growth behavior of world population and aquaculture production during the
last six years. (a) illustrates the total world population by year
(billions) and the total production of aquatic organisms by aquaculture
(million tonnes). (b) compares the percentage of annual increase of world
population and aquaculture production, considering year 2004 as the
basepoint. Data obtained from FAO Report 2010: World Review of Fisheries and
Aquaculture.
(a)
(b)Despite the undeniable benefits of aquaculture such as the provision of good quality
and accessible food for population and the generation of millions of jobs and
billion dollars in budget for the developing countries, the activity is one of the
most criticized worldwide, mainly because of the environmental impacts that have
been and can be caused. Thus, the predominant and unavoidable question is: could
aquaculture be a truly sustainable activity?Understanding sustainability as “the ability to meet the needs of the present
without compromising the ability of the future generations to meet their own
needs” [3], many researchers,
aquaculturists, and governmental instances have considered that a sustainable
aquaculture is possible, but it depends on the way that the activity will be managed
[4]. Additionally, other authors [5] have argued that “the sustainability
of aquaculture not only requires neutral or benign effects on the environment, but
also economic feasibility.”The present paper is a review of the world aquaculture and its environmental impacts.
It analyzes the situation of aquaculture production up to date and summarizes the
main problems faced by the activity, as well as the strategies suggested, evaluated,
and proven to contribute to achieve a sustainable activity.Aquaculture Is an Essential Activity for World’s Welfare
Aquaculture is considered as a double-edged sword, because it has not only
tremendous benefits for the humanity, but also great repercussions to the
environment. Considering the benefits, seafood produced by fisheries and
aquaculture contributes with 15 to 20% of average animal protein
consumption to 2.9 billion people worldwide [6] without considering the contribution of freshwater or brackish
water species. The nutritional quality of aquatic products has a high standard
and represents an important source of macro- and micronutrients for people from
developing countries [7]. Additionally,
aquaculture and fisheries are recognized as a source of employment; for
instance, near to 43.5 million people were employed in 2006, and 520 million
people relied on income from seafood production [6, 8].
Aquaculture products have also high trade potential as food commodities in the
international market; fish and shellfish exports from developing countries have
a greater value than the combination of important products such as coffee, tea,
tobacco, meat, cocoa, rubber, and rice [6,
8]. In many cases, the incomes
generated by aquaculture exceed those from other agricultural activities, due to
the high price market that some products can achieve and due to the most
effective bioenergetics of some aquatic species. However, despite all these
benefits, aquaculture is actually not considered a sustainable activity in the
perception of the scientific community and the average population.


## 2. Why Aquaculture Is Considered a Nonsustainable Activity?

With or without valid arguments, aquaculture has been accused to be the cause of many
environmental, social, economic, and inclusively esthetic problems. Ecosystems are
not always as fragile as could be considered, instead, they have remarkable capacity
of resiliency, and as long as basic processes are not irretrievably upset,
ecosystems will continue to recycle and distribute energy [9]. However, irreversible damages have been already caused due
to inadequate management of the activity. The main negative impacts attributed to
the activity are as follows.(1) Destruction of Natural Ecosystems, In Particular Mangrove Forests to
Construct Aquaculture Farms [4, 10, 11]
The mangrove forests are important ecosystems considered as the main source of
organic matter to the coastal zone [12,
13]; they are also nursery areas for
many aquatic species ecologically and/or economically important, as well as
refuge or nesting areas for bird, reptiles, crustaceans, and other taxonomic
groups [14]. Mangroves are additionally
accumulation sites for sediments, contaminants, nitrogen, carbon and offer
protection against coastal erosion [15].
According to environmentalists [16],
mangroves support diverse local fisheries and also provide critical nursery
habitat and marine productivity which support wider commercial fisheries. These
forests also provide valuable ecosystem services that benefit coastal
communities, including coastal land stabilization and storm protection.
The cover of mangrove forest has decreased worldwide from 19.8 million hectares
in 1980 to less than 15 millions in 2000. The annual deforestation rate was
1.7% from 1980 to 1990 and 1.0% from 1990 to 2000 [17], and the problem continues up today.
Some authors have documented that aquaculture has been responsible for the
deforestation of millions hectares of mangrove forest in Thailand, Indonesia,
Ecuador, Madagascar, and other countries [18, 19]. From 1975 to 1993,
the construction of shrimp farms in Thailand diminished the mangrove cover from
312,700 to 168,683 ha [20].
Philippines has reconverted 205,523 ha of mangrove and wetlands into
aquaculture farms, Indonesia 211,000 ha, Vietnam 102,000 ha,
Bangladesh 65,000 ha, and Ecuador 21,600 ha [21].(2) Salinization/Acidification of Soils
Aquaculture farms are sometimes abandoned by multiple problems (operative,
economic, sanitary, and etc.), and the soil from those former farms remain
hypersaline, acid and eroded [22].
Therefore, those soils cannot be used for agricultural purposes and are unusable
for long periods. In addition, the application of lime and other chemicals used
in aquaculture to treat the soil can also modify its physicochemical
characteristics, which could aggravate the problem [23].(3) Pollution of Water for Human Consumption
Although few studies have been conducted in relation with such topic, there are
some signs indicating that inland aquaculture has been responsible for the
deterioration of water bodies used for human consumption [21]. For instance, preliminary calculations revealed that
an intensive aquaculture system farming three tons of freshwater fish can be
compared, in respect to waste generation, to a community of around 240
inhabitants [24].
Although most of the aquaculture farms produce marine species, there is a growing
sector of aquaculture farms producing freshwater species, which is a point of
concern considering the above information.(4) Eutrophication and Nitrification of Effluent Receiving Ecosystems
The eutrophication or organic enrichment of water column is mainly produced by
nonconsumed feed (especially due to overfeeding), lixiviation of aquaculture
feedstuffs [25, 26], decomposition of died organisms, and overfertilization
[27–30]. It is well documented that from the total nitrogen
supplemented to the cultured organisms, only 20 to 50% is retained as
biomass by the farmed organisms, while the rest is incorporated into the water
column or sediment [31, 32], and eventually discharged in the
effluents toward the receiving ecosystems, causing diverse impacts such as
phytoplankton blooms (sometimes of toxic microalgaes, such as red tides) [33], burring, and death of benthic
organisms, as well as undesirable odors and the presence of pathogens in the
discharge sites [34]. The impact may be
more or less severe depending on some factors such as the intensification of the
system (density of organisms), which is directly related to the amount of feed
supplied [26, 35]. The feed conversion ratio (FCR) is a well indicator of
the effectiveness of feeding and, consequently, of the retention of nitrogen and
carbon as biomass of the farmed organisms. For instance, farms culturing the
tiger shrimp Penaeus monodon usually report FCRs ranging from 1
to more than 2.5; such huge difference is later reflected in the amount of
organic matter, nitrogen, and phosphorous discharged in the effluents, which may
range from 500 to 1625 kg, 26 to 117 kg, and 13 to 38 kg,
respectively, for each ton of shrimp harvested [28]. The estimated mean FCR worldwide for shrimp aquaculture is 1.8,
which means that, for a world annual shrimp production around 5 million tons,
5.5 million tons of organic matter, 360,000 tons of nitrogen, and
125,000 tons of phosphorous are annually discharged to the environment.
Unfortunately, these data considers only shrimp production, which represents
around 8% of the total aquaculture production; if we assume that the FCRs
are similar for the other farmed organisms and the diet formulations have some
similitude [36], the total discharge of
wastes may be multiplied by 12.5 from a very preliminary perspective. The
nutrification is considered as the nutrient (N, P, C) enrichment of water
column, mainly due to fertilization, mineralization of organic matter,
resuspension of sediments, and excretion of organisms into the ponds. The
greatest concern in this aspect is the increasing production of nitrogenous
metabolites especially ammonia, which is highly toxic in its unionized form
(NH3) for many aquatic organisms [37].(5) Ecological Impacts in Natural Ecosystems because of the Introduction of
Exotic Species
The negative impacts of the “biological contamination” for the
introduction of exotic aquacultural species on the native populations have been
well documented [18, 38, 39]. The main reported problems are the displacement of native
species, competition for space and food, and pathogens spread. To cite an
example, recent reports have revealed a parasite transmission of sea lice from
captive to wild salmon [40]. The authors
of such study have hypothesized that “if outbreaks continue, then local
extinction is certain, and a 99% collapse in pink salmon abundance is
expected in four salmon generations.”(6) Ecological Impacts Caused by Inadequate Medication Practices
Farmers usually expose their cultured organisms to medication regimes, for
different purposes such as avoiding disease outbreaks and improving growth
performance. However, monitoring studies have detected low or high levels of a
wide range of pharmaceuticals, including hormones, steroids, antibiotics, and
parasiticides, in soils, surface waters, and groundwaters [41]. These chemicals have caused imbalances in the
different ecosystems. In particular, the use of hormones in aquaculture and its
environmental implications have been scarcely studied.(7) Changes on Landscape and Hydrological Patterns
The agricultural and aquacultural activities have contributed to the degradation
of ecosystems including important modification on landscape [10, 18, 22, 42]. The construction of shrimp farms in the river beds has
modified the hydrological patterns in many regions of the world with the
consequent impacts on the regional ecosystems and the local weather.(8) Trapping and Killing of Eggs, Larvae, Juveniles, and Adults of Diverse
Organisms
It has been estimated that, for each million of shrimp postlarvae farmed, four to
seven millions of other organisms are killed by trapping in the nets of farms
inlet [18, 43].(9) Negative Effect on Fisheries
Although aquaculture has been proclaimed as a solution to avoid overfishing, it
has contributed in more or less proportion to the fisheries collapse. Fishermen
who work in places near to aquaculture farms argue that the contamination
produced by farms has decreased the population of aquatic organisms and in
consequence their volume captures. Additionally, another problem of similar
magnitude is the extremely high aquaculture’s dependence of fishmeal and
fish oil, which could be another nonsustainable practice in aquaculture. The
proportion of fishmeal supplies used for fish production have increased from
10% in 1988 to more than 30% in the last years, which classifies
aquaculture as a potential promoter of the collapse of fisheries stocks
worldwide [24].(10) Some Other Accusations
Some other accusations for aquaculture include the production of fish and
shellfish with high concentrations of toxins and/or heavy metals; genetic
pollution and infestation of nondesirable phytoplankton and/or zooplankton
species [44–47].(11) In Its Role as Food Producer, Aquaculture Is Far from Complying an
Adequate Distribution of Food
Overlaying net exports, governance, and undernourishment suggest that
“seafood’s contribution as a source of protein and livelihood is
precarious” [6]. Moreover, it has
been revealed that some countries with undernourishment and weak governance
usually play a role as baler of seafood from countries well nourished and with
strong economic capacity [6].
For these above reasons remains a generalized perception that the sustainability
of aquaculture is at present being threatened or, in some cases, far from being
reached.


## 3. What to Do for a Sustainable Aquaculture?

Many strategies have been suggested, evaluated, and/or proven in order to advance in
the sustainability of aquaculture. Basically, all of them respond to the criticisms
and are possible solutions to the problems attributed to the activity. The main
aspects that have to be performed to advance toward such goal are the correct
selection of the farming sites and species; the implementation of the most adequate
culture system; use of the best feed and feeding practices; the use of
bioremediation systems; decreasing the dependence of fishmeal and fish oil; adequate
management of the effluents; achieving certification of compliance with
sustainability; improving research and legislation related to evaluation and
solutions for aquaculture impacts.(1) In the context of the site selection it is necessary to consider the following.(a)
The vocation of the selected site. It would be absurd to select a site
for aquaculture purposes if it is excellent for agriculture or
livestock. Unfortunately, this is the case in many regions of the world,
where agricultural lands have been reconverted to aquaculture farms. The
vocation of a selected site is determined for many aspects (which can
change from region to region) such as physical and chemical soil
characteristics; water availability, soil fertility, topography, wild
vegetal and animal communities, proximity to cities, towns, tourism
zones, and so forth; priorities of the region or country (food, fuels,
tourism budget, aquaculture budget, and etc.).
(b)
The carrying capacity of the water bodies from the sites considered to
supply the farms or used as effluent discharge places. It is very
important to evaluate how much water can be taken from a particular
water body or how much effluents it can receive without important
alterations on its ecological equilibrium [48]. The use of advanced technologies such as
remote sensing could be an excellent auxiliary in this field [11].(2) For the selection of species it is crucial to consider the following.(a)
It is always better to select native instead of exotic species. The
introduction of exotic species causes many and diverse problems as
mentioned in the previous section. Additionally, the obtaining and
maintenance of broodstock of exotic species could be difficult and
expensive.
(b)
It is necessary to have the most possible knowledge about the biology and
ecology of the organism that is pretended to be farmed (life cycle,
feeding habits and nutritional requirements, tolerance to environmental
parameters, and etc.).
(c)
It is important to select organisms with a good market and price when
farmed for commercial purposes.(3) Regarding implementation of the best culture system, the main aspects to consider
include the following.(a)
The type and size of farming structure [49]. Depending on the species, intensity, land and water
availability, and economic investment, it is possible to use different
types of farming structures for the culture of the same species or
group. Some of them are more adequate and sustainable. For the case of
shrimp farming, for instance, it has been suggested that floating or
submerged cages could have a lower impact on the environment than
earthen ponds. The same suggestion is applicable for culture of fishes
or mollusks. Regarding size of production units, small ponds or farming
structure is easier to manage in aspects such as feeding, monitoring,
cleaning, pond bottom management, and harvesting. Such considerations
usually lead to lower environmental impacts.
(b)
Intensity. The stocking density and the consequent biomass harvested are
absolutely related to the sustainability of aquaculture. The increase of
the intensity implies an increase in the supplemental feed and in
consequence, in the organic matter, nitrogen, and phosphorous in the
effluents. Additionally, intensive or super intensive systems require
the use of diverse chemicals (antibiotics, algaecides, parasiticides,
and etc.), which also contribute to increasing the pollution [50]. The most adequate intensity
depends on the land and water availability, as well as the carrying
capacity of the water body or terrestrial ecosystems which will receive
the effluents. However, recalculating and zero water exchange systems
can eliminate the environmental impact while maintaining extremely high
densities of aquatic organisms. Promising results have been achieved in
the culture of fish and crustaceans using biofloc systems with zero
water exchange [51].
(c)
An adequate design of the water inlet and outlet systems, considering the
water quality, weather conditions, marine currents and tide patterns
(for sea water), and hydrological patterns (for continental waters)
[52]. The modifications of
oceanic currents patterns may have implications on the sediment
transport and consequently on the beaches conformation.
(d)
The possibility of farming simultaneously two or more species
(polycultures or integrated multitrophic aquaculture (IMTA)). This
strategy has proven to be one of the most effective ways to recuperate
the carbon, nitrogen, and phosphorous supplied to the system as biomass
of the farmed organisms and to diminish the environmental impacts caused
by the effluents [53–55]. Polyculture is commonly
referred to organisms of the same environment (marine, brackish
wáter, or continental waters) and trophic level, while IMTA is
mostly referred to organisms from different trophic levels and
inclusively different environments. The implementation of such
alternative systems improves the nutrient cycling within the culture
units. In short, while in a traditional aquaculture system, 25 to
35% of the nitrogen supplied is recuperated as biomass of the
farmed organisms, in a polyculture or IMTA, the recuperation could be
increased by more than 50%. A pilot project made aware and informed
a group of participants about the benefits of IMTA; the authors revealed
that 50% of the participants were willing to pay an extra 10%
of products labeled as of “IMTA products.” Moreover, the
authors were optimistic regarding the social impacts caused by the
implementation of IMTA as a sustainable practice [5].(4) Since supplemental feed is considered the main source of contamination of
aquaculture systems and effluent receiving ecosystems [56], the improvement of these feed, as well as the feeding,
strategies could be considered as an important part of the solution for a
sustainable aquaculture [28, 57]. The main aspects in which the feedstuffs
must be improved include the following.(a)
Better and more precise formulations for the particular species to be
farmed, which consider the best concentration and quality of the
nutrients. A common practice of world aquaculture is the use of diets
with protein contents higher than those required, thus affecting not
only the price of the feed but also increasing the pollution potential,
considering that protein catabolism produces ammonium nitrogen as the
main metabolite. Regarding nutrient quality, it is important to use
ingredients with high digestibility; the low digestibility of
ingredients (protein, lipid, carbohydrate) is partially the responsible
for a low retention of those nutrients in the farmed organisms and their
increase in the water column and sediment, augmenting the polluting
potential [58].
(b)
Higher hydrostability. One of the most important causes of nutrient
losses of aquafeeds is the low hydrostability, which provoke fast
disintegration and lixiviation, decreasing the nutrient incorporation
efficiency by the farmed organisms and increasing the concentration in
the water column. Fishes are faster swimmers and can consume a
formulated feed within minutes, but crustaceans are usually less active
and can consume the formulated feed within minutes or even hours. The
hydrostability of feedstuffs can be improved by incorporation of
effective binders and/or for the use of special fabrication processes
[59].
(c)
Better attractability and palatability. It is necessary to produce feeds
which can be consumed as soon as possible to avoid nutrient losses. This
is possible with the incorporation of effective attractants and
improving the palatability with ingredients such as fish oils and
others. Many of these ingredients have been sufficiently proven [60].(5) Regarding to the feeding strategies some important advances have been achieved
but there are yet much more to advance in aspects such as forms to supply the feed,
adjustment of the ration, and frequency of feeding.(a)
The use of feeding trays and the increase of feeding frequency have been
demonstrated to diminish the pollution potential of the effluents in
shrimp farms [37]; however these
strategies are suitable only for high-intensity systems (intensive or
superintensive), but not economically feasible for extensive,
semiextensive of semiintensive systems.
(b)
The promotion, management, and rational utilization of natural feed,
including microorganisms (biofilm, biofloc), are considered as a
promising strategy for the culture of shrimp, fishes, and mollusks. Some
authors [61–63] have successfully enhanced the
production of zooplankton and benthos in shrimp ponds and demonstrated
their great contribution not only in the production response, but also
in the nutritional, sanitary, and immune condition of the farmed
organisms. Additionally, the use and contribution of microorganisms
associated to biofilms and bioflocs for the nutrition of farmed
organisms have been also documented [24, 64–66]. Such practice may also
decrease the dependence of fishmeal and fish oil; however other
strategies such as the use of plant ingredients and the use of
bioflocflour have been tested and proposed to substitute at different
rates the fishmeal in formulated feeds [51].
(c)
The practice of subfeeding or intermittent-feeding regimes is a strategy
aimed to achieve average growth performances in aquatic organisms, but
supplying significantly lower amounts of formulated feed. Such
alternative takes advantage of the compensatory growth process of shrimp
and crustaceans [67].(6) The adequate management of effluents is indubitably one of the central aspects
to consider for a sustainable aquaculture. Diverse strategies have been proven or
suggested to minimize the environmental impacts of effluents. The most promising are
settling lagoons [34], treatments with septic
tanks [68], the implementation of systems
with low or zero water exchange [69], the
utilization of recirculation systems [70,
71], the use of mangrove forests as sinks
for nutrients, organic matter, and contaminants [72], the polyculture or integrated multitrophic aquaculture systems
[55, 73], and the bioremediation [54,
74].(a)
It is considered as bioremediation the use of individual or combined
organisms (including animal, vegetal, and bacteria) to minimize the
contaminating charge of effluents from any activity (including
aquaculture). This practice takes advantage of the natural or modified
abilities of those organisms to reduce and/or transform waste products
[75].
(b)
There are different ways to conduct bioremediation: in situ, ex situ,
biostimulation, bioaugmentation, and others. Many successfully examples
of bioremediation practices can be mentioned: the use of plants
(phytoremediation), macroalgae, microalgae, filter feeders, biofilters
(polymer spheres with immobilized microorganisms), biofilms, and
bioflocs [76, 77]. There are also combined
systems which use two or more of these practices. Many studies have been
conducted to use individual or combined organisms for bioremediation
[78–80]. However, the ideal strategy
would be the decreasing or complete halting of effluent discharge and
using zero water exchange systems.(7) Achieve certification of compliance with sustainability.A combination of analyses has been suggested to evaluate the sustainability of
commercial aquaculture farms [81]. For
example, the authors of such contribution suggest the calculation of mass balances
and undesirable outputs of shrimp farms; calculation of the input distance function
approach which provides a complete characterization of the structure of multiinput,
multioutput efficient production technology and provides a measure of the distance
from each producer to that efficient-sustainable technology; finally a productivity
measurement with and without undesirable outputs. However, the analysis of the
socioeconomic impacts caused by farms ought to be included in the list.Additionally, certification processes can be followed to assure the sustainability of
aquaculture or to compare the standards established by the different agencies and
check if the practices of any farm cope with those standards. The certification of
aquaculture is performed by the International Standards Organization (ISO), the WTO
Technical Barriers to Trade (TBT), the FAO Guidelines for the Ecolabelling of Fish
and Fishery Products from Marine Capture Fisheries, and the Network of Aquaculture
Centres in Asia-Pacific (NACA) and others [82].According to the FAO criterion [82],
certification “is a procedure through which written or equivalent assurance
states that a product, process, or service conforms to specified requirements.
Within the aquaculture sector certification can be applied to a process followed by
a production unit (pond, cage, farm, processing plant), a specific product or
commodity or to the inputs being applied to the system before or during
production.”(8) Finally, there is an unavoidable need to improve research and legislation
regarding evaluation and solutions for aquaculture impacts.(a)
One of the reasons of the severe environmental impacts of aquaculture is
that scientific research in some developing countries is firstly focused
on increasing biomass production (improvement of formulated feeds,
production systems, genetically improved organisms, etc.) and later on
the environmental impacts; however, it is desirable to evaluate the
potential impacts of any farm that is pretended to be installed, rather
than monitoring the pollution that is already being caused by any farm
constructed without considering its environmental impact.
(b)
In addition, there is a great heterogeneity regarding policies and
legislation of aquaculture impacts among different countries; while some
developed countries have complete and concrete legislation for
aquaculture in order to avoid environmental impacts, others have weak
policies that do not protect their environment from aquaculture wastes;
under such scenario ecological imbalances and disasters have been
caused, with some of them being irreversible. Herein, Smith et al.
asserted that “some developing countries often lack the
institutions necessary to prevent deleterious ecosystem impacts of
seafood production and to sustain trade benefits” [6]; they also argued that
“the developed countries have a history of these problems as
well, but with less-obvious consequences.” In the same report,
the authors revealed that with base in the World Bank indicators, more
than 60% of the countries had inefficient governance regarding the
regulation of aquaculture and fisheries activities; a possible cause of
such result is related to corruption and regulatory quality. Thus, it is
absolutely essential for the future of aquaculture that the governments
and the producers be attuned with each other to reach agreements that
resolve the problems of this activity.
(c)
Finally, contrasting actions have been observed by governmental
instances, while some instances try to protect the environment and
achieve a sustainable aquaculture, others have directly or indirectly
supported the unsustainable aquacultural practices; for instance,
according to a recent report [16]
“the conversion of mangroves to aquaculture ponds has been
fuelled by governmental support, private sector investment and external
assistance from multilateral development agencies such as the World Bank
and Asian Development Bank” [83, 84].In conclusion, aquaculture is a possible panacea, but at present is also responsible
for diverse problems related with the environmental sanity; however the new
strategies proposed during the last decade have proven that it is possible to reach
a sustainable aquaculture, but such strategies should be supported and proclaimed by
the different federal environmental agencies from all countries. Only under such
scenario, aquaculture will be a sustainable practice. The implementation of the
different alternatives stated above would depend on particular circumstances of any
farm. Fortunately, there are reports of some aquaculture farms along the world on
sustainable practices.



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