Malta Case Study

Nutrient retention of fish farm effluent and site assessment for Integrated Multi- trophic Aquaculture (IMTA) in Malta

Case study description
The Central Mediterranean case study of the TAPAS project carried out by AquaBioTech Group in Malta will investigate:

  • The mapping of visible impacts of sea bream cage aquaculture on the marine environment to identify possible conflicts with the tourism industry.
  • The dispersion and retention of nutrients from the fish farm to provide data for improving environmental impact assessment models and to describe the impacts on Posidonia oceanica meadows.
  • The development of a new method to identify the most appropriate spots around fish farms to produce extractive species in IMTA.

AquaBioTech Group will conduct a case study to quantify the nutrition dispersion and retention in the environment surrounding a sea bream farm in the Marsaxlokk Bay, Malta.

In the first stage of the research, sample collection and analysis was carried out to illustrate the distribution of suspended solids from the fish farm. The TAPAS research team will collect samples of benthic flora to analyze the nutrients retained by of the surrounding ecosystems. The isotopic compositions will demonstrate the dispersion of nutrients from fish farm effluent and show which organisms or substrate retained the most nutrients. A Remote Operated Vehicle (ROV) with digital video recording and sediment sampler will be used to perform a benthic survey to assess the marine communities surrounding the fish pens.


The data obtained will be used to improve the existing waste dispersion models and to develop a new method to identify the best conditions and locations for the production of extractive species in an IMTA system.

The second stage of the research will evaluate and test the site assessment method by stocking selected extractive IMTA organisms in the identified locations while continuing to investigate the nutrient dispersion and retention patterns. To obtain more data about the impacts of aquaculture on the water quality and visibility in the water, the newly developed WISP system also will be tested in the case study.

The use of case study data in TAPAS
The main outcomes of the case study research in Malta will be fed directly in the following work packages and tasks:

  • The collected data will be used in WP5 to improve and validate existing near-field models (Task 5.2, 5.3) and WP2 will investigate how these improved models can be used in the regulatory framework development in Malta (Task 2.6).
  • The data on nutrient retention and the IMTA production of locally consumed species will provide input to identify management and incentive strategies that facilitate sustainable aquaculture development and maximize societal benefits in WP4 (Task 4.4)
  • Testing the WISP tool in oligotrophic marine environment will support the development of novel real-time in situ measurement systems in WP7 (Task 7.2)
  • The method developed for IMTA site assessment will be an element of the TAPAS SMART decision-making tool and best practice inventory (Task 8.2, 8.3)

The state of the case study research in June 2017

The first trial phase of the project started in May and data collection aims to be finished by September 2017. We placed an invertebrate rack system in the Marsaxlokk fish farm and examined the water quality with the WISP system to collect initial data about the site. We deployed a total of 8 sedimentation trap along the boundary of the fish farm to measure the amount of collected suspended organic material to help illustrate any predominant current patterns.