Integrated seaweed cultivation on an abalone farm in South Africa |
| |
Authors: | Deborah V Robertson-Andersson Michelle Potgieter Joakim Hansen John J Bolton Max Troell Robert J Anderson Christina Halling Trevor Probyn |
| |
Institution: | (1) Botany Department, University of Cape Town, Rondebosch, 7701, South Africa;(2) Department of Systems Ecology, Stockholm University, SE 106 91 Stockholm, Sweden;(3) Department of Systems Ecology, Stockholm Resilience Centre, Stockholm University, SE-106 91 Stockholm, Sweden;(4) The Beijer International Institute of Ecological Economics, The Royal Swedish Academy of Sciences, Box 50005, S-104 05 Stockholm, Sweden;(5) Seaweed Unit, Marine and Coastal Management, Pvt Bag X2 Roggebaai, South Africa;(6) Aquaculture Unit, Marine and Coastal Management, Pvt Bag X2 Roggebaai, South Africa;(7) Biodiversity and Conservation Biology, University of the Western Cape, Bellville, 7535, South Africa |
| |
Abstract: | Land-based abalone aquaculture in South Africa, based on the local species Haliotis midae, started in the early 1990s and has grown rapidly in the last decade, with 13 commercial farms now producing over 850 t per
annum. Over 6,000 t per annum of kelp Ecklonia maxima are now harvested for this purpose, and some kelp beds are reaching maximum sustainable limits. Research into seaweed aquaculture
as feed (Ulva and some Gracilaria) for abalone started in the late 1990s on the southeast coast (where there are no kelp beds) using abalone waste water. A
growing body of evidence suggests that a mixed diet of kelp plus other seaweeds can give growth rates at least as good as
compound feed, and can improve abalone quality and reduce parasite loads. A pilot scale Ulva lactuca and abalone integrated recirculation unit using 25% recirculation was designed and built on the south west coast of South
Africa using one 12,000-L abalone tank containing 13,200 15 ± 2.5 g abalone, connected to two 3,000-L seaweed tanks containing
an initial starting biomass of 10 kg of seaweed, replicated 3 times. In an 18-month period, there were no significant differences
in abalone health or growth rates, sediment build up and composition, mobile macro fauna densities and species between the
recirculation or the flow-through units. Transfer of oxygen generated by the seaweeds to the abalone tanks was poor, resulting
in the recirculated abalone tanks having lower (33%) dissolved oxygen concentrations than a comparable flow-through abalone
unit. Seaweed nutrient content and specific growth rates in the units were comparable to seaweeds cultivated in fertilized
effluent (SGR = 3.2 ± 3.4%.day−1; Yield = 0.2 ± 0.19 kg.m2.day−1). Indications were that at this low recirculation ratio the seaweeds in the units were nutrient limited and that there were
no negative effects to the abalone being cultivated in such a recirculation unit at this recirculation ratio. |
| |
Keywords: | Integrated Abalone Seaweed Aquaculture Ulva Recirculation |
本文献已被 SpringerLink 等数据库收录! |
|