Literature Review take on IMTA systems

The team conducted a literature review regarding the current state of IMTA systems, the New Zealand environment and regulations to determine how an IMTA system should be incorporated and whether it could succeed. 

From the literature review, the best species to integrate together in New Zealand are suggested to be the Chinook Salmon, green-lipped mussels and seaweed. With majority of New Zealand’s $500 million revenue from aquaculture production already coming from both green-lipped mussels and salmon, these two species will be the most profitable and easiest to establish into an IMTA system. For the seaweed grown in a New Zealand IMTA, to sell it internationally as food it would need to be marketed as a premium product to be profitable. Instead, it is suggested that the seaweed be used to produce fertilizers and bio-stimulants to help support New Zealand’s horticulture and agriculture, making it more environmentally friendly. To increase profitability and the likelihood of success, it is advisable to incorporate the IMTA system into an already established salmon farm. With salmon being the only specie that requires an external input adding mussels and seaweed would only require the initial cost of lines, floats and anchors. 

There is potential for IMTA systems to be established both inshore, offshore and on land. Offshore has great potential as it has been noted that it increases shellfish growth due to the increased current activity. However, it is currently not as feasible nor profitable as a sheltered near shore system. Land based also has the potential to reduce escapees and increase sustainability of the company but it does have a much greater carbon footprint and requires external energy through pumps and filtration mechanisms. This suggests that an inshore and sheltered system would be more profitable and successful.

A large potential danger to an IMTA system is eutrophication. This can be mitigated through seaweed species selection by choosing species that have varying harvest times and by optimising the co-cultivation proportions which can be observed through water samples that are already expected from salmon farms.

It was concluded that an IMTA in New Zealand would be beneficial for both the environment and the economy and by incorporating it to an already existing salmon farm makes it more likely for success.