AEI 8:1-13 (2015)  -  DOI: https://doi.org/10.3354/aei00158

Redox stratification drives enhanced growth in a deposit-feeding invertebrate: implications for aquaculture bioremediation

Georgina Robinson1,2,*, Gary S. Caldwell1, Clifford L. W. Jones2, Matthew J. Slater1,3, Selina M. Stead1

1School of Marine Science and Technology, Newcastle University, Newcastle NE1 7RU, UK
2Department of Ichthyology and Fisheries Science, Rhodes University, Grahamstown 6140, South Africa
3Alfred-Wegener-Institute, Helmholtz Center for Polar and Marine Research, Am Handelshafen 12, 27570 Bremerhaven, Germany
*Corresponding author:

ABSTRACT: Effective and affordable treatment of waste solids is a key sustainability challenge for the aquaculture industry. Here, we investigated the potential for a deposit-feeding sea cucumber, Holothuria scabra, to provide a remediation service whilst concurrently yielding a high-value secondary product in a land-based recirculating aquaculture system (RAS). The effect of sediment depth, particle size and redox regime were examined in relation to changes in the behaviour, growth and biochemical composition of juvenile sea cucumbers cultured for 81 d in manipulated sediment systems, describing either fully oxic or stratified (oxic-anoxic) redox regimes. The redox regime was the principal factor affecting growth, biochemical composition and behaviour, while substrate depth and particle size did not significantly affect growth rate or biomass production. Animals cultured under fully oxic conditions exhibited negative growth and had higher lipid and carbohydrate contents, potentially due to compensatory feeding in response to higher microphytobenthic production. In contrast, animals in the stratified treatments spent more time feeding, generated faster growth and produced significantly higher biomass yields (626.89 ± 35.44 g m-2 versus 449.22 ± 14.24 g m-2; mean ± SE). Further, unlike in oxic treatments, growth in the stratified treatments did not reach maximum biomass carrying capacity, indicating that stratified sediment is more suitable for culturing sea cucumbers. However, the stratified sediments may exhibit reduced bioremediation ability relative to the oxic sediment, signifying a trade-off between remediation efficiency and exploitable biomass yield.


KEY WORDS: Sea cucumber · Holothuria scabra · Sandfish · Value-added aquaculture · Recirculating aquaculture · Bioturbation · Compensatory feeding


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Cite this article as: Robinson G, Caldwell GS, Jones CLW, Slater MJ, Stead SM (2015) Redox stratification drives enhanced growth in a deposit-feeding invertebrate: implications for aquaculture bioremediation. Aquacult Environ Interact 8:1-13. https://doi.org/10.3354/aei00158

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