"Sustainability" and "sustainable" are
popular words these days, but often misused. We understand it as producing food
while sustaining natural resources and achieving it only through production
systems with minimal ecological impact.
The most common relation is linking environment with sustainability. If
something does not impact the environment or has a positive impact on it, it is
considered sustainable. However, there are other factors that might come into
play when considering a product or production system's sustainability.
RAS as case study
We conducted a survey among different stakeholders whose opinions are critical
for the advancement of the aquaculture industry. One of the questions we asked
was why RAS is considered "environmentally friendly" fish production methods.
Responses were received from all over the world and the main reasons given
were: less water usage from the environment compared to other culture
technologies, such as ?ow through systems; decrease of the eutrophication
potential of the outgoing water; elimination of potential disease transfer and
genetic contamination of wild stocks; use of no or very little vaccines or
antibiotics because of a biosecure culture environment; and the possibility of
re-using discharged nutrients in agriculture.
Nonetheless, in practice, sustainability of RAS was considered uncertain and
the use of energy and its environmental impact was of little concern to the
respondents. In fact, concerns identi?ed by the stakeholders included (Fig. 1):
identifying alternatives to ?shmeal (35%); enhancing animal welfare (i.e.
increased biomass production, increased survivals and reduced maturation with
the subsequent reduction of product downgrades) (26%); decreasing the feed
conversion ratio (23%); decreasing the use of chemicals (11%); and decreasing
the use of energy and thus, created environmental impacts (5%).
Energy plays an important role when considering the sustainability of RAS.
Respondents were also asked about techniques or strategies applied in relation
to energy recovery systems designed/applied. Examples included exchanging heat
between the incoming (i.e. make-up water) and outgoing water through a
heat-exchanger; retaining heat based on the system's operation/water use;
controlling the energy use of CO2 stripping through pH/CO2 set-points for
on/off control of blowers for energy saving and; increasing the recirculation
rate through the use of denitri?cation technologies which resulted in energy
use reduction and cost savings. Using system sludge for local farming purposes
and producing energy for other nearby companies through a bioreactor supplied
by sludge, guts from the processing stage and mortalities, were also mentioned.
Typical environmental benefits of RAS are less water and land use, greater
control over the environmental and water quality parameters enabling optimal
conditions for fish culture, and high biosecurity standards. However, there is
something else beyond this. There are many other reasons to consider such
systems as environmentally sustainable. RAS are located where consumers are,
decreasing the transportation and thus the carbon footprint of each of the
marketed products. RAS producers are committed to promote site-specific energy
sources such as renewable energies and zero or near-zero impact initiatives
within the local community. The recapture and reuse of waste from the system,
included in a lifecycle assessment throughout the whole production cycle, make
it possible to consider such systems within circular economy business models.
Aquaculture is the production of fish, the industry of the future, the
(potential) engine of many communities in developing countries and the promising
farming method to meet the seafood demand in technological and economically
advanced areas. Society needs aquaculture as aquaculture needs society.
RAS produces absolutely fresh products, possibly and potentially certified,
available all year round. Moreover, these systems allow full traceability of
the product, from egg to the table, giving consumers the confidence of
purchasing a trustworthy product. The site selection by investors and/or
company managers also guarantees local employment and economic development.
This positively contributes to local job creation and generates ripple effects
in the local supply and service sectors. RAS can promote aquaculture (and
related areas) through schools, universities and research companies as well as
investing in R&D with continuous feedback from stakeholders.
However, society and consumers need to be educated. The understating of what
fish production is and the implications of the industry in the near and further
future is crucial. RAS companies need to educate fish eaters about the benefits
of sustainable choices. The importance and awareness relies on the information
strategies to adopt sustainable seafood choices.
Should technology and the economy also be considered when defining the
sustainability of RAS? Learn about sustainability and the circular
economy, which radically limits the extraction of raw materials
and the production of waste, recovers and reuses as many of the products
and materials as possible, in a systemic way, over and over again.
The prevailing model of production and management of resources that promote
short-term consumption is leading the planet to an unsustainable outcome. In
contrast, the circular economy is a "make/remake - use/reuse" economy that
offers substantial improvement.
Repoduced From Hatchery International, by Maddi Badiola, PhD, is a RAS engineer and co-founder of HTH aquaMetrics
LLC, (www.hthaqua.com) based in Getco, Biscaye, Basque Country, Spain. Her
specialty is energy conservation, life cycle assessments and RAS global