236 Marine Macro- and Microalgae: An Overview
macroalgae in a range of aquaculture systems. Several examples will be given of the incorporation of
macroalgae to increase the environmental and economic sustainability of land-based aquaculture systems
and also aquaculture at sea.
IMTA an historical perspective
IMTA can be traced back to the origins of aquaculture. In China, the integration of fish with aquatic
plants and vegetable production and the development of cage culture has been described as early as 2000
BC by You Hou Bin. Moving fast forward in time and to the Fertile Crescent region, there is evidence
of tilapia grown in integrated agriculture-aquaculture drainable ponds on bas-reliefs in Egyptian tombs
from about 1550–1070 B.C. In Europe, during the French Renaissance, an IMTA system was built at the
Château de Fontainebleau, the Etang aux Carpes (Carp Pond). Moving again to China, Xu Guangqi wrote
the Nong Zheng Quan Shu, an outstanding agricultural treatise (The Complete Book on Agriculture)
published posthumously in 1639. The treatise covered many topics, including irrigation and the rotation
of fish and aquatic plant production, the integration of fish with livestock and the effects of manure on
pond production, and the integration of mulberry trees, rice paddies, and fish ponds (Chopin 2013). So,
when rice/fish culture started to be popular in Europe in the 19th–early 20th centuries, it had already been
practiced in China for millennia (Fernando 2002).
In the West, this type of integration never fully developed into commercial scale and aquaculture
only started its expansion in the 20th century. From then to now more species were brought into culture
and the industry continued to expand both in area and in quantity of production. Only in the late 20th
century aquaculture started to work with economies of scale. A new trend to select species that are
most profitable to culture was adopted by operators in the industry: for example, Penaeid shrimps and
high value finfishes (seabass/groupers), and seaweeds and related species started to become interesting
aquaculture products (Rabanal 1988). In many places aquaculture developed into an industrial aquaculture
food system, based on a monoculture system with high tech methods, and intensification of production
towards more efficiency, higher production with lower costs.
However, with the rapid expansion of intensive monoculture systems several environmental and
socio-economic problems also started to arise. A major issue, pointed out by several authors, is that
Western-oriented aquaculture has been managed as an isolated part of its supporting environment (Folke
and Kautsky 1992). In the 1970s, the eutrophication problem, with oxygen depletion, biodiversity
modifications and pollution of the surrounding waters, was one of the first concerns leading to research
on IMTA. According to Chopin (2013), John Ryther and co-authors reignited the interest in IMTA and
can be considered the grandfathers of modern IMTA for their pivotal work entitled “integrated wasterecycling marine polyculture systems” (Ryther et al. 1975). The main aim was to recreate a cultivating
system based on a food chain, capable of providing an effluent virtually free of inorganic nitrogen, thus
avoiding the risk of eutrophication in the receiving waters (Ryther et al. 1975).
This work was followed by three productive decades addressing this issue under many different
designations including polyculture, integrated mariculture, integrated aquaculture, ecologically
engineered aquaculture, and ecological aquaculture (Chopin 2013). Then in 2004, Thierry Chopin and
Jack Taylor, understanding the need to harmonize all these names, combined integrated aquaculture and
multi-trophic aquaculture into the term integrated multi-trophic aquaculture—IMTA (Chopin 2013). Even
though the designation is fairly recent, the concept is ancient. Nevertheless, the designation brought with
it the research debate, which has evolved and is developing to new commercial and legal perspectives.
The role of seaweeds in IMTA—research approach
In 1975, Ryther and co-authors described the development and testing of a combined tertiary sewage
treatment/marine aquaculture system. In this work, red seaweeds were included as a final inorganic
nutrient bio filtration unit in a complex system. This used domestic wastewater effluent from secondary
sewage treatment mixed with seawater as a source of nutrients for growing unicellular marine algae.
These microalgae served as feed for oysters, clams, and other bivalve mollusks. Polychaete worms,
macroalgae in a range of aquaculture systems. Several examples will be given of the incorporation of
macroalgae to increase the environmental and economic sustainability of land-based aquaculture systems
and also aquaculture at sea.
IMTA an historical perspective
IMTA can be traced back to the origins of aquaculture. In China, the integration of fish with aquatic
plants and vegetable production and the development of cage culture has been described as early as 2000
BC by You Hou Bin. Moving fast forward in time and to the Fertile Crescent region, there is evidence
of tilapia grown in integrated agriculture-aquaculture drainable ponds on bas-reliefs in Egyptian tombs
from about 1550–1070 B.C. In Europe, during the French Renaissance, an IMTA system was built at the
Château de Fontainebleau, the Etang aux Carpes (Carp Pond). Moving again to China, Xu Guangqi wrote
the Nong Zheng Quan Shu, an outstanding agricultural treatise (The Complete Book on Agriculture)
published posthumously in 1639. The treatise covered many topics, including irrigation and the rotation
of fish and aquatic plant production, the integration of fish with livestock and the effects of manure on
pond production, and the integration of mulberry trees, rice paddies, and fish ponds (Chopin 2013). So,
when rice/fish culture started to be popular in Europe in the 19th–early 20th centuries, it had already been
practiced in China for millennia (Fernando 2002).
In the West, this type of integration never fully developed into commercial scale and aquaculture
only started its expansion in the 20th century. From then to now more species were brought into culture
and the industry continued to expand both in area and in quantity of production. Only in the late 20th
century aquaculture started to work with economies of scale. A new trend to select species that are
most profitable to culture was adopted by operators in the industry: for example, Penaeid shrimps and
high value finfishes (seabass/groupers), and seaweeds and related species started to become interesting
aquaculture products (Rabanal 1988). In many places aquaculture developed into an industrial aquaculture
food system, based on a monoculture system with high tech methods, and intensification of production
towards more efficiency, higher production with lower costs.
However, with the rapid expansion of intensive monoculture systems several environmental and
socio-economic problems also started to arise. A major issue, pointed out by several authors, is that
Western-oriented aquaculture has been managed as an isolated part of its supporting environment (Folke
and Kautsky 1992). In the 1970s, the eutrophication problem, with oxygen depletion, biodiversity
modifications and pollution of the surrounding waters, was one of the first concerns leading to research
on IMTA. According to Chopin (2013), John Ryther and co-authors reignited the interest in IMTA and
can be considered the grandfathers of modern IMTA for their pivotal work entitled “integrated wasterecycling marine polyculture systems” (Ryther et al. 1975). The main aim was to recreate a cultivating
system based on a food chain, capable of providing an effluent virtually free of inorganic nitrogen, thus
avoiding the risk of eutrophication in the receiving waters (Ryther et al. 1975).
This work was followed by three productive decades addressing this issue under many different
designations including polyculture, integrated mariculture, integrated aquaculture, ecologically
engineered aquaculture, and ecological aquaculture (Chopin 2013). Then in 2004, Thierry Chopin and
Jack Taylor, understanding the need to harmonize all these names, combined integrated aquaculture and
multi-trophic aquaculture into the term integrated multi-trophic aquaculture—IMTA (Chopin 2013). Even
though the designation is fairly recent, the concept is ancient. Nevertheless, the designation brought with
it the research debate, which has evolved and is developing to new commercial and legal perspectives.
The role of seaweeds in IMTA—research approach
In 1975, Ryther and co-authors described the development and testing of a combined tertiary sewage
treatment/marine aquaculture system. In this work, red seaweeds were included as a final inorganic
nutrient bio filtration unit in a complex system. This used domestic wastewater effluent from secondary
sewage treatment mixed with seawater as a source of nutrients for growing unicellular marine algae.
These microalgae served as feed for oysters, clams, and other bivalve mollusks. Polychaete worms,