IS IMTA JUST A BUZZWORD FOR POLYCULTURE? REDEFINING THE IMTA CONCEPT

Abstract

Clear definitions are essential for understanding rules, concepts, and phenomena, preventing confusion with other terms, enabling clear communication, and supporting progress in any field. In aquaculture, there are many types of technical and biological solutions that try to improve productivity or tackle environmental problems related to faeces and uneaten feed. Particular attention has been given to a specific form of polyculture - integrated multi-trophic aquaculture (IMTA), which treats wastes from primary fed organisms using organic and inorganic extractive organisms that can be utilised as additional crops. Despite its clear conceptual foundation, IMTA is increasingly used as a catch-all term for almost any form of polyculture. Our study explains why an oversimplified definition of IMTA as a system in which the waste of one organism is utilised by another results in IMTA being practically the same as polyculture, thereby questioning the need for this new concept with high popularity. Based on a reassessment of the earliest IMTA literature, we propose four criteria that must be fulfilled for a system to qualify as IMTA sensu stricto. They give a clear distinction between true IMTA systems and other polycultures, such as aquaponics, fish-crustacean polycultures and others, which we systematically organise and discuss. We also systematically analyse 769 indexed articles mentioning IMTA, checking their compliance with the criteria. By clarifying IMTA terminology in line with its original concept, this paper provides a framework that supports more precise classification, comparison, and development of sustainable aquaculture systems.

Methods

We conducted a systematic review of peer-reviewed IMTA studies using Scopus and Web of Science, searching titles, abstracts, and keywords for "integrated multi-trophic aquaculture", "integrated multitrophic aquaculture", or "IMTA" AND "aquaculture". After filtering for English-language research articles, removing duplicates and reviews, 769 publications remained for analysis. Taxa mentioned in each document were automatically identified using custom R code and an extensive taxonomic dictionary, standardizing organism names to unified taxonomic groups. Organisms were then classified into primary cultured species, organic extractive species, and inorganic extractive species, while feeding status was assigned based on taxonomic and contextual rules. The automated workflow was validated on a random subset of 50 articles, confirming high consistency in taxa recognition and functional classification.

Figure 1

Figure 1: IMTA-related articles and their proportions of using fed organisms (A), secondary extractive organisms (B) and fulfilment of IMTA 4 criteria (C).

Figure 2

Figure 3: The most frequently used taxa in IMTA-indexed research: overall (A) and in combinations of primary raised species and organic extractive species (B).