E-paper content
Different Types of Aquaculture Production System
· Highlights
of topic:
· What
is Aquaculture?
·
Types of
farming practices in aquaculture
· Advances in aquaculture
production systems
·
What is Aquaponics?
· What is Biofloc technology?
·
Integrated
multi-trophic aquaculture
·
Recirculatory
aquaculture system (RAS)
·
What is organic
aquaculture?
· What is Aquamimicry?
Aquaculture
production systems are constantly modified for
bringing ease in operation and attaining higher efficiency in terms of cost and
benefits. The current article aims is highlighting the recent technological
advancements in the aquaculture systems based on the R&D efforts and
indigenous technical knowledge (ITK).
Introduction
Fish
represent both a vital contribution to the human food supply and an extremely
important component of world trade and economy. The world capture fisheries attained almost a stable and
constant production during the recent years. Whereas the aquaculture production
tends to be dynamic and aquaculture shows an increasing trend. Fisheries sector
serves as a substantial source of income and livelihood for hundreds of
millions of people around the world and it comparatively remains a crucial
source of food and nutrition. The global population in 2020 is around 7.8
billion and it is anticipated to reach more than 9 billion by 2050.
Global fish production reached about 179 MMT in 2018, with a total
sale value of USD 401 billion. 82MMT of this production, valued at USD 250
billion, came alone from aquaculture. Of the total production, 156 million
tonnes were used for human food, equivalent to anannual supply of 20.5 kg per
capita. (FAO, 2020).
The
following table represents the world fisheries and aquaculture production till
the year of 2018 (SOFIA, 2020).
Types
of farming practices in aquaculture
Aquaculture
refers to the cultivation/ rearing/raising of aquatic organisms for commercial,
recreational or public purpose. Due to diversification of aquaculture
operations, the description of various types of aquaculture systems may be
intricate and puzzled too. Aquaculture is an extremely diverse enterprise. Aquaculture
is performed in very different environments (freshwater, brackish water,
saltwater), which represent extremely distinguished environmental and physiological
challenges to the animal being raised and to the associated fauna and flora. This
is also work with many different species, where some estimates exceed 600
economically important culture sand the number is growing each year.
Based
on the type of enclosure and water sources aquaculture can be broadly
categorized into:
1. Open culture
e.g. Bivalve culture, Pen culture, cage culture.
2. Semi enclosed culture
e.g. Pond culture, Raceways.
3. Closed culture
e.g. RAS, biofloc based system.
4. Hybrid system
e.g. integrated farming, Aquaponics, In pond raceways, Aquageoponics,
Aquasilviculture, Aquamimicry.
Like other culture systems,
aquaculture is also restrained by many constraints like cultural, environmental,
health and disease, nutritional, waste management and domestication related
issues. These issues are being addressed from time to time by various
scientific and technological interventions. The various levels at which the
technology was modified and enhanced may broadly include:
1. Hatchery
management and Brood stock management
2. Types
of advanced farming system likeaquaponics, biofloc, IMTA, organic aquaculture, race
way culture, RAS
3. Advancement
in cage & pen culture
4. Advances
in monitoring the culture practices and quality of the product, BMPs, eco-labeling,
bio-security
5. Genetic
level improvement
6. Diet
based regulation on aqua farming
Advanced
technology for hatchery management
The need of water in hatchery
operation, which was profuse earlier, is now being fulfilled with the help of
recirculatory system that includes mechanical as well as bio filtration. So
that the water quality can be maintained and water requirement can be
fulfilled. Nutritional and prophylactic measures are being employed to increase
the growth and health of organisms like use of species-specific feeds and
feeding methods, live, bioenriched feed for larvae, feed size specifications,
nutritional immunostimulants, use of probiotic, prebiotics, herbal stimulants
etc.
Advances in quarantine measures have
ensured the check and corrective action of a pathogenic spread. Brood
management, genetic improvement of animalsand control of reproduction are core
parts of an aquaculture business that allow a successful hatchery and improve
efficiency and productivity of the entire aquaculture venture.
Less focus on genetic improvement and
poor hatchery operations, in both developed and developing countries, has
significantly downsized the performance of many species due to the phenomenon
of inbreeding, genetic drift and uncontrolled gene pool mixing. This warrants a
routine change of the stock to alleviate the problems of reduced brood and
hatchery performance.For example, properlymonitored selective breeding operations
have shown continual improvements in performance and quality. For instance,Atlantic
salmon breeding companies have revealed more than 100 %enhancement in growth
performance in nearly six generations, with significantimprovements in
immunedefense and delays in the onset of sexual maturation.
Advances in aquaculture production systems
Various
aspects of production systems like water management, waste disposal, animal
welfare, area utilization, seed production and other facility are being
modified timely. Due to the efforts various modern and technologically advanced
systems like RAS, biofloc, high intensity cage cultures, in pond raceways,
aquapoics, aquamimicry, partitioned ponds and many more are being brought into
the operations. Such system help in profit maximization using much reduced area
than the conventional pond culture systems. Simultaneously the issues are water
management is also addressed by making recirculatory systems using various
mechanical and biological filters.
Following is the account related to a few advanced
aquaculture production systems.
1.
AQUAPONICS
Aquaponics
involves the integration of aquaculture and hydroponics in a recirculating
aquaculture system, where plants grow without soil.
The main components
include:
a. Water
– Recirculated
and topped up with rainwater harvesting.
b. Wastes
– fish wastes and nitrates are stabilized by plants, offcuts and worms are
consumed by fish.
c. Heat
– heating gains in the day and heat losses at night and thus may require heat
seals or thermostats.
These
fish-plant systems are intended to raise large quantities of fish in relatively
lesser volumes of water by treating the water and then reusing it. However, in
the process of reusing the water, many nontoxic nutrients and organic matter can
accumulate in the system and can lead to nutrient loading.
Aquaponics
system
2. BIOFLOC TECHNOLOGY
This
method is based on the maintenance of extreme levels of bacterial floc in water columnby providingconstant aeration and addition of carbohydrates, in orderto allow
aerobic breakdown of the organic material present within. By adding sugars like
molasses, rice bran, potato starch, etc, heterotrophic microbial growth is stimulated and production of
microbial proteins occurs through nitrogen uptake and
transformation. Biofloc is a
conglomerate assemblage of microscopicunits such as phytoplankton, bacteria, and particulate organic matter, dead or alive.
Biofloc technology aims at establishing a specific C/N ratio to convert toxic
nitrogenous compounds into the useful microbial protein and simultaneously improve
water quality under a zero water exchange system. (Ahmad, I., Rani, A.B.,
Verma, A.K. and Maqsood, M., 2017)
3. INTEGRATED MULTI-TROPHIC
AQUACULTURE (IMTA
Integrated multi-trophic aquaculture
is predominantly practiced under mariculture where it is usedto biologically mitigate
ecological effects of mariculture in oceans. Its advantages are prompting
increased attention and interest among researchers and farmers, especially in
developed nations. It provides the byproducts or residuals or waste, from one
aquatic system as inputs (in the form of fertilizers or food) for anotheraquatic
system. IMTA conjoinsartificially fed aquaculture (e.g., fish, shrimp,
crawfish, etc) with inorganic extractive (e.g., seaweed) and organic extractive
(e.g., shellfish aquaculture) to create balanced systems for environment
sustainability and development through biomitigation. It also leads to economic
stability (improved output, lower cost, product diversification and risk
reduction) and social acceptability (better management practices).
Fig: Process flow
diagram (Clements et. al., 2016)
4.
RECIRCULATORY AQUACULTURE SYSTEM
(RAS)
A recirculating
aquaculture system (RAS) is an approach for the removal of metabolic and
otherwastes from the culture water without harming environmental integrity
(Gutierrez-Wing and Malone 2006).The beneficial effect of this technology is
that only 10% of the total water volume is needed to be replaced on a daily
basis (Twarowska et al. 1997). The practice of RAS in developing nations is
greatly limited due to the higher costs of the technology and requirement of
technical expertise.
Recirculating
aquaculture system (RAS)
5.
ORGANIC AQUACULTURE
Organic
aquaculture is the sustainable management system that advocates and enhances endemic
biodiversity, original biological cycles, and biological activity and emphasize
on minimum use of off farm inputs, holistic management practice that regenerates,
maintains and enhance species biodiversity along ecological integrity. It has
gained popularity globally as a sustainable farming system, which maintains the
long-term viability of the soil and uses less of the Earth’s limited resources
to produce quality, nutritious and hazardless food. This raises animals without
antibiotics growth promoters, chemicals, fertilizers, GMO products and production
is achieved while preserving the ecosystem and biodiversity.
6.
Integrated floating cage
Aquageoponics system (IFCAS)
Aquageoponics is a new version of
traditional aquaponics where soil is used as a medium to grow plants within the
cage surface instead of conventional media such as pebbles and sponges in
aquaponic systems. This approach can extends the growing potential of rural areas
where land is a major constraint. This farming technique uses water from culture
media and uses it to grow crops while it purifies and stabilizes the water for
fish in the cage or pond. In return the waste products generated by fish supply
nutrients for the growing vegetables. This system finds its origin from
Bangladesh (Haque et. al., 2015).
Integrated
floating cage Aquageoponics system (IFCAS)
AQUASILVICULTURE
It is a
management tool that connects and harmonizes fish production and mangrove restoration
and development. This innovation has become a favorable earning opportunity to
sustainably augment income and, at the same time maintain the mangrove
ecosystems. This mainly originated from the indigenous knowledge and experience
based sustainable skills. Such systems
are commonly used in Southeast Asia like Indonesia and Vietnam and in the early
stages of development in Hong Kong, the Philippines, and Malaysia. The approach differsplace to place but mainly
aims at the integration of mangrove ponds and impoundments for fish and crabs
(Primavera,2000).
AQUAMIMICRY
Aquamimicry is a concept that implies
on simulating natural estuarine phenomenon by creating zooplankton community
blooms (mainly copepods) as supplemental food to the cultured shrimp and flourishing
beneficial bacteria to stabilize water quality. This is attained by
fermentingcarbohydrates, such as rice or wheat bran, with probiotic microbes
(like Bacillus sp.) and releasing their constituent nutrients.
This method is in line with the technology of biofloc, but there are some main
differences:
Firstly,
the amount of added carbohydrate source is less and not strictly added based on
ratios to nitrogen inputs. Secondly, rather than promoting and suspending high rates
of bioflocs, solids are removed in more intensive systems to be reused by other
farming systems/practices.
Potential
problems related to aqamimicry may include difficulty of applying this concept
to indoor conditions andthe use of relatively large treatment ponds.
PARTITIONED
PONDS (PAS)
PAS confines fish at high densities
in concrete raceways that comprise about 5% of the total pond area. Wastes formedin
fish ponds are distributedto a large, turbulentwater
spreadarea with appropriate algal bloom density for the treatment.these
large basins were originally designed for sewage treatment (Oswald, 1963). The
concept originated from the Ictalurid
fish culture in United States.
Broadly
there are two variants of this system
In-Pond
Raceway Systems (IPRS): In this system, the already
existing pond is built with a group of raceways in it. The fish are cultured in
the raceways while the rest pond water area acts as a waste stabilization
lagoon for the culture waters.
Split-ponds:
In
this system, the large water body is divided into two by raising a suitable
embankment in a levee form. The smaller section is used for holding fish and
from there the water is pumped in the larger section and that acts as a waste
stabilization lagoon with an optimum algal density maintained in it.
PARTITIONED
PONDS (PAS)
About Author
Credit of Writing: Writing credit
of this article goes to M. Junaid Sidiq, Ph.D scholar, Department of
Aquaculture, Central institute of Fisheries Education –Mumbai (India) and Dr. M.A. Rather, Div. of Fish Genetics and Biotechnology, SKUAST-K