Integrated multitrophic culture of white shrimp with mullet in a biofloc system

Editor/Mohamed Shihab

The following is an extract from an article published by Panorama da Aquicultura:

Mullet (Mugil liza) is a promising species to integrate multitrophic crops. When young, species of the Mugilidae family reveal a plankton-eating habit, becoming iliophagous in adulthood, when they mainly consume plant matter removed from silt or sand. This feature gives them great ecological importance due to their ability to convert the potential energy of debris into energy that can be used at other trophic levels. In this article, an experiment whose results show the functionality of an integrated multitrophic system composed of shrimp L. vannamei and mullet, used as a natural filter of excess suspended solids from cultivation in a biofloc system.

The concept of integrated multitrophic aquaculture (AMTI) aims at managing a balanced ecosystem that provides environmental sustainability, economic stability and social acceptability.

In general it includes:

1-a target species, which is fed with specific feed;

2-species that consume organic matter, which take advantage of the remains of particulate matter from the target species; It is

3-nutrient-consuming species that were not used by previous species.

A classic example of multitrophic cultivation is that of salmon integrated with oysters (consumers of particulate matter) and macroalgae (consumers of nutrients).

There are also systems where several other components with different functions are incorporated, such as the absorption of particles of different sizes, or even with different production cycles, which can be harvested before the end of the cycle of another species. There are also components that are incorporated with the purpose of feeding on deposited material, such as sea cucumber, urchin and polychaetes, which are arranged in cages at the bottom of the crops, or in suspended trays.

The most advanced integrated systems, many operating on a commercial scale, are located in Canada, Chile, South Africa, Israel and China, and research projects related to the subject, and mainly with integrated multitrophic aquaculture on shore, are taking place in several places in the world.

In Brazil, UNESP has been working with AMTI in traditional systems and FURG and UFSC are developing research with multitrophic aquaculture integrating fish, shrimp and aquatic plants in a biofloc system.

Despite the benefits of the biofloc system, little or no water renewal results in the accumulation of total suspended solids (TSS) and nutrients (nitrate and phosphate) that can be harmful to farmed animals when they reach very high levels. The constant increase in TSS results from the formation of bioflocs, which are microbial aggregates composed of heterotrophic and chemoautotrophic bacteria that consume nitrogenous compounds (ammonia and nitrite) from the production system. This excess of bioflocs deteriorates the water quality and can lead to occlusion of the gills, a fact that increases the sensitivity of the animals to hypoxia, negatively affecting the growth of the animals and, consequently, increasing the energy cost of maintaining dissolved oxygen levels within limits. suitable for the species Litopenaeus vannamei. [Continues...]

Authors: Mariana Holanda, Gabriel Santana, Plínio Furtado, Ricardo Rodrigues, Luís André Sampaio, Wilson Wasielesky Jr. and Luis H. Poersch | Aquaculture Overview | Read the complete article by clicking here (Only available in Portuguese)

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