Felsing M, Telfer T & Glencross B (2006) 15N-enrichment of an aquaculture diet and tracing of cage culture waste in an estuarine environment. Journal of Applied Ichthyology, 22 (5), pp. 419-426. https://doi.org/10.1111/j.1439-0426.2006.00744.x
A method was developed to use the stable isotope 15N to trace the fate of cage aquaculture-derived nutrients at an experimental cage aquaculture site in Fremantle Harbour, Western Australia. Artificial enrichment of a finfish diet in 15N was achieved through the enrichment of the macroalgae Ulva rigida, which was fed to rainbow trout (Oncorhynchus mykiss) to produce 15N-labelled fishmeal. From the subsequently produced fishmeal, a pelleted feed with a 15N signal of 298 ± 58‰ (mean ± SE) was produced and fed to pink snapper (Pagrus auratus) in a seacage. Strong enrichment (15N range: 38-53‰) was detected in primary producers and suspended particulate organic matter in the vicinity of the cage immediately following enrichment, and a delayed uptake (to 15N 15.9 ± 0.2‰, mean ± SE) was detected in deposit feeders under the cage 14 days following enrichment. No further enrichment signal could be detected near the cage in this short-term trial. The limited accumulation of aquaculture waste in the vicinity of cages was supported by findings from concurrent environmental monitoring. It was concluded that artificially enriched aquaculture feeds provide a sensitive method for tracing aquaculture wastes in the environment, but that further development of the technique is required to make it viable for more widespread use.
Journal of Applied Ichthyology: Volume 22, Issue 5
|Publication date online||02/06/2006|
|Date accepted by journal||19/08/2006|