Three pilot actions are jointly conducted:
- Pilot 1 aims to test new eco-friendly technologies and high value seaweeds (Codium tomentosum, Palmaria palmata, Porphyra purpurea, Himanthalia elongata and Ulva spp.) applied to IMTA.
- Pilot 2 focuses on near-shore eco-friendly developments of the integrated Porphyra spp. + oyster system.
- Pilot 3 tests and develops an IMTA eco-friendly standard model for land-based semi-extensive aquaculture industry. This will explore different combinations of fish, bivalves and seaweeds.
PILOT 1: new eco-friendly technologies and high value seaweeds
Pilot 1 studies innovative IMTA systems to find alternatives to organic and inorganic extractive components for Atlantic IMTA. Experiments will monitor performances of different IMTA associations in controlled systems. Also, IMTA’s underdeveloped benthic component will be assessed to develop suitable technologies to support it. The market potential of Atlantic IMTA seaweeds will be improved by developing production techniques for new high-value species.
Pilot 1 partners are AGROCAMPUS OUEST and CEVA (France), NUIG and ISC (Ireland), SAMS (UK) and ALGAPLUS (Portugal).
- NUIG: Ulva/lumpsucker recirculating systems
The 8 recirculating systems we have been building are very close to completion and we are ready to begin the first growth trials in January.
Coming in 2019 we will begin the growth and nutrient uptake assays for the ulva and analyse the harvested ulva for metals, protein, CHN.
- ISC: Cultivation Himanthalia elongata:
Sea Spaghetti is ready to go to Sea!
The Irish Seaweed Consultancy (ISC) is cultivating Himanthalia elongata (Sea spaghetti) as a potential new species in an IMTA system.Eggs and sperm were continuously released from August until end of October. Throughout this time scallop shells were used as a seeding substrate , with good attachment results. Shells covered with fertilised Himanthalia eggs are now in aerated tanks, waiting to be moved to the IMTA farm this winter.
- CEVA : Definition and optimization of culture conditions for Codium tomentosum and Palmaria palmata
Assays for at-sea cultivation: Because at-sea cultivation of Codium tomentosum is forbidden in France, only the hatchery stage is operated. Different materials have been seeded with either C. tomentosum or P. palmata.
After a 1 month cultivation in hatchery, Palmaria palmata materials were transferred to CEVA’s at-sea farm. The at-sea cultivation will run until June 2019. C. tomentosum is kept in hatchery tanks.
Coming in summer 2019: analyses of biomass and chemical contents (Pigments, proteins, amino acids, heavy metals, polysaccharides).
Land based assays: The objective here is to test the efficiency of current materials used by other aquaculture sectors (Mussel and Oyster productions) as supports for seaweed aquaculture.
Coming early 2019: analyses of biomass and chemical contents (Pigments, proteins, amino acids, heavy metals, polysaccharides).
- ALGAPLUS: Porphyra and Codium optimized methods for cultivation in earthen ponds.
Assays were started in September 2018 and are still running.
Although there are occasional problems with epiphytes, especially during summer. A parallel project has been set up to look into how light can be used to control epiphytes.
- AGROCAMPUS-OUEST: Integrated cultivation of Ulva, mussels and Sea cucumbers.
Experimental cultivation was designed and assays are expected to be launched early 2019.
Pilot 2: near-shore eco-friendly developments of the integrated Porphyra spp. + oyster system.
Pilot 2 seeks to develop efficient management techniques for Porphyra-oyster IMTA systems. The wild collection and hatchery production of Porphyra are being assessed in order to provide oyster farmers with new tools to support their diversification efforts, and to bring new supplies to the seaweed industry and new hatchery best practice.
Pilot 2 partners are CEVA and AGROCAMPUS OUEST (France) and Algaplus (Portugal).
ALGAPLUS has started different trials with Porphyra in tanks and earthen ponds.
- CEVA: Porphyra purpurea strains collection and cultivation trials in French oyster farms
7 French oyster farms have been identified where Porphyra purpurea naturally settle on oyster pockets.
13 strains from these 7 farms were collected and isolated. Vegetative cultivation is in progress in order to build one strain collections of conchocelis.
Coming spring 2019:
- Optimization of vegetative cultivation of conchocelis
- Hatchery cultivation of seeded oyster pockets
- Transfer in oyster farms
Coming summer 2019: Development of efficient harvest techniques for P. purpurea adapted to oyster farming.
Pilot 3: IMTA eco-friendly standard model for land-based semi-extensive aquaculture industry.
Pilot 3 focuses on land-based IMTA systems combining fish, molluscs, invertebrates and seaweed/salt tolerant plants. The possibility of controlling water flow through different compartments makes land-based systems an excellent candidate for successful Atlantic IMTA.
During the first stage of the pilot, CTAQUA has set up its experimental land-based IMTA system and tested the performance of combined oyster (Magallana gigas –Crassostrea gigas) and seaweed (Ulva sp. & Gracilaria gracilis) farming technologies.
Seeding of the upper trophic levels (fish and oysters) in the first culture unit was done in June-July 2018. A total 1500 gilthead seabream (Sparus aurata) with an average weight of 40 grams were placed in the system and are manually fed a commercial fish feed twice a day.
3000 spat of oyster with an average size of T10 –equivalent to an average weight of 4g- were seeded in the same culture unit, i.e. sharing the culture space with the gilthead seabream.
The oysters are grown in the mesh oyster bags typically used in intertidal zones. However, instead of the traditional rack support system, the bags are attached to floating devices arranged on a long-line as per IPMA’s design. This system has so far performed well and is proving to be a good solution for convenient husbandry and cleaning. The pilot started off with 5 oyster bags and is currently running 20.
Seaweeds were first seeded onto a long-line system implemented in an earthen pond. Despite initial promising results, this system soon failed due to a bryozoan (Amathia verticillata, Bugula neritina) invasion which added excess weight to the ropes, thus making them sink below the euphotic zone and causing total loss of the seaweeds. Long-lines were replaced by seaweed floating cage systems that so far have proved suitable for the land-based IMTA set-up. Initial fine tuning was required and some losses were recorded, but from there onwards our seaweeds’ growth rates have been good and bryozoan invasions have ceased to be an issue. CTAQUA has implemented 8 seaweed cages in 2018.
The system is protected from predation by anti-cormorant bird netting.
In order to test the performance of the farming systems and the growth of the organisms, we have implemented a biometrics sampling strategy for the fish, the oysters and the seaweed biomass.
The fish will be sampled twice a year so as to prevent unnecessary stress, while oysters are being sampled monthly because they grow faster and the farming system we are using is new to our area. Besides, oyster-rearing in bag systems requires frequent size grading and thinning to ensure uniform growth. The oysters’ condition index is also monitored in the lab for the entire duration of the culture period in order to keep track of their growth and health.
Regarding the seaweed, apart from monitoring biomass we take regular tissue samples to analyse their nutrient content.
Finally, it is very important to monitor water quality in the culture units. Vital parameters such as temperature, salinity and dissolved oxygen are recorded in situ and water samples are collected twice a month coinciding with spring and neap tides, i.e. periods of maximum and minimum flow between the compartments. Dissolved nutrient levels are recorded (nitrites, nitrates, ammonium, phosphate, Nt and Pt) to monitor nutrient uptake in the each of the compartments of the multi-trophic system.
Coming up in the pilot action
We are now entering the slow growth winter period, which is expected to last until February 2019. Monthly seaweeds & oyster sampling and water quality monitoring will continue while significant growth is registered and then the frequency will be gradually reduced to couple it to slow growth.
According to our sampling strategy, the fish will be sampled in January 2019.
Once the slow growth period is over, CTAQUA will gradually increase the number of seaweed cages until we reach our maximum capacity of 20 cages (16 Ulva sp. and 4 Gracialria gracilis).