Aquaculture Canada and WAS North America 2022

August 15 - 18, 2022

St Johns, Newfoundland, Canada

INTRODUCING SIBS: ‘SUBSTRATE INDEPENDENT BENTHIC SAMPLER’ FOR HARD AND MIXED-BOTTOM HABITATS: A PROOF OF CONCEPT STUDY

Nigel Keeley*, Olivier Laroche and Xavier Pochon

*Institute of Marine Research, 9007 Tromsø, Norway (nkeeley@hi.no)

 



 As is the case in most countries, the  Norwegian standard for monitoring  of  organic impacts of salmon farming is centered

 around the analysis of chemical and biological parameters of soft-sediments habitats . However, m any fish farms are situated in areas with hard or mixed substrates and  this is likely to increase given the anticipated

 shift to more  physically  dynamic sites.

Although a nalogous changes are probably occurring on these mixed-bottoms

habitats , our knowledge of

any

potential interactions is severely lacking , and more critically,

 are going largely unmonitored due to the absence of a suitable sampling method.

 There are however emerging alternative biological indicators that may provide a solution. Recently, several studies have demonstrated

the potential of using genetic material from micro-organisms (e.g. bacteria, foraminifera etc.), assessed

 through rapid, high-throughput sequencing techniques, to discern benthic enrichment. To date, these have been necessarily restricted

to sampleable soft-sediment habitats. The small, ubiquitous, highly abundant and diverse nature of these

organisms means that they are likely to be present in the biofilms and/or flocculent layers that

 overly most hard- and mixed-bottom substrates.

 Here we present the first set of results using eDNA to describe the microbial communities of samples collected using a newly developed ‘Substrate Independent Benthic Sampler’ device. Samples were obtained from sand, shellsand , gravel, and bedrock using a low-cost surface operated suction device and are compared to more conventional  microbial  eDNA samples  from soft-sediments  and to macrofauna samples, where feasible. Minor differences were observed between sample types and farms, but in general, very g ood congruence wa s observed between the datasets with respect to distance from farm and anticipated benthic effects. Sampling of flocculent material overlying all substrates provides a potentially vital monitoring tool for the management of fish farm effects in the future.