Designing a marine aquaponics
(maraponics) system to model IMTA
Daryl Gunning; Luke Harman; Mairead Keily; Rory Nunan; Peter Jones; Ben Horgan; Gavin Burnell
Aquaculture and Fisheries Development Centre, University College Cork, Ireland
Typical Integrated Multi‐Trophic Aquaculture array
Troell, M., and J. Norberg
(1998). Modelling output and retention of suspended solids in an integrated salmon‐
mussel culture. Ecological Modelling 110: 65‐77.
Typical RAS system with hydroponics
(Waller et al. 2014)
Aquaponics = Aquaculture + hydroponics
Converting an IBC to a maraponics unit
Why marine aquaponics?
• Hard to demonstrate nutrient recycling in oligo/mesotrophic open water IMTA
• Difficult to obtain licenses for mixed species culture in Ireland
• Closed RAS allows full control of inputs
• RAS allows behavioural observations
• Experiment with different species mix
• Reduced sampling variability (diurnal/tidal)
• Possible to test disease transfer
Trophic levels
• Level 1: Plants and algae make their own food and are called primary producers.
• Level 2: Herbivores eat plants and are called primary consumers.
• Level 3: Carnivores that eat herbivores are called secondary consumers.
• Level 4: Carnivores that eat other carnivores are called tertiary consumers.
• Level 5: Apex predators that have no predators are at the top of the food chain.
• Level 6: Detritivores – eat organic material
• Level 7: Decomposers (bacteria and fungi) – modify nutrients
Model maraponics ecosystem
Pmy producer
Pmy producer
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Tertiary consumer
Pmy consumers
Detritivores
P
Pmy consumers
Decomposer
P
Research questions
• Will rainbow trout (Salmo gairdneri) become steelheads and drive the system?
• What species of macroalgae and halophytes
will grow in our system?
• Can we use fatty acid profiles to trace nutrients through the animals?
• Can we use stable isotopes to trace nutrients into the algae?
• Will be able to record growth of sea cucumbers?
Maraponics & Salicornia europaea
Unlike freshwater aquaponics, where there are a multitude of plant component choices (e.g. lettuces, herbs etc.), a marine system has a limited number of suitable plant species available S. europaea was chosen as a candidate species in an experimental IMTA/Maraponics
system as it is extremely salt‐
tolerant and commercially valuable and has potential as a bio‐filter
S. europaea growth trials
• Preliminary Research:
 Trial One: No pre‐germination treatment. Controlled light conditions (16:8 light:dark), no temperature control. 5% seedling emergence
 Trial two: No pre‐germination treatment. Temperature, humidity and light controlled growth room. 15% seedling emergence
 Trial three: Cold stratification pre‐
germination treatment. Ambient light and temperature conditions. 100% seedling emergence
Growth of Salicornia in aeroponics unit
Sea Cucumber Anaesthesia
• Why?
 more accurate measurements
 reduce stress prior to treatments such as tagging Anaesthesia Results
 When anesthetised with 1%, 1.5%, and 2% MgCl2, variation in mean weight measurements was significantly reduced  Variations in length measurement were only reduced when specimens were exposed to 2% MgCl2. However, there was no significant difference in variation of length measurements pre‐ and post anaesthesia Sea Cucumber Tagging
1) Tagged dorsally
2) Tagged ventrally
3) Tagged at the head‐region
***Tags are 1.4mm x 8mm (Trovan ®)
Tagging Results
Tag Retention
90
80
% Individuals 70
60
50
Dorsal
40
Ventral
Head Region
30
20
10
0
24 Hours
1 Week
2 weeks
3 weeks
4 Weeks
6 Weeks
Time
 The most successful position was dorsal, with a 25% retention rate after one week
 All tag positions showed a poor retention rate with 0% within two months
Outreach and Education
1. Ecoponics –
2. Maraponics
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3. Miniponics
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