Assessment of the impact of Atlantic bluefin tuna farming on Adriatic benthic habitats by analysing macroinvertebrate assemblage structure at family level

Abstract

The rapidly expanding Atlantic bluefin tuna fattening industry is characterized by high stock densities and a high input food biomass in the form of whole bait seafood. The environmental impact of this activity must be effectively monitored within a proper sustainable development framework, to address concerns about the potential adverse effects. However, evaluation of monitoring tools for tuna farming has received less attention than other activities. Based on the principles of key taxa (Pocklington and Wells, 1992), we tested the potential use of changes in benthic macroinvertebrate assemblages, polychaetes and amphipods for this purpose. Applying a non-parametric multivariate approach for monitoring the impact of this aquaculture activity on the benthic habitat, we checked for correlations with the physicochemical environmental variables of the sediment. A hierarchical spatial design was followed, using multiple controls. Amphipods and polychaetes showed dissimilarities between impacted and control locations, with significant differences for total assemblage structure at a taxonomic level of families. Total nitrogen (TN) and total sulfur (TS) concentrations were the variables best associated with these changes for amphipods, and d 13C and total phosphorus (TP) were the best for polychaetes. However, total free sulfides (TFS) and TP were the chemical variables that best indicated the effects on sediment. Using this approach, surrogating the whole benthic assemblage to a single taxocene, our data suggest that monitoring tuna farming impact by comparing the changes in amphipod and polychaete assemblages at family level could be an optimal procedure with an excellent cost/benefit ratio.

Changes in trophic behaviour and trace metal concentrations in wild fish in a tuna-farming environment. The key role of a sound baitfish choice

“…In Europe, studies exploring the influence and effects of coastal aquaculture have principally focused on salmon, sea bass, and sea bream facilities. However, remarkable changes have also become evident in the areas hosting Atlantic bluefin tuna (BFT) (Thunnus thynnus) cages, with subsequent effects on the local ecological communities surrounding the cages (Aguado et al, 2004;Moraitis et al, 2013;Die 2016;Mangion et al, 2018;Sanchez-Jerez et al, 2018). These effects principally include the aggregation of abundant and diverse fish communities that are closely associated with the cages (Šegvić Bubić et al, 2011;Bacher et al, 2012;Stagličić et al, 2017).…”

Impact assessment of fish cages on coralligenous reefs through the use of the STAR sampling procedure

“…However, the impact of aquaculture on natural systems is an increasing cause of environmental concern (Holmer, 2010). In fact, light reduction and deposition of particulate carbon have been described to have profound effects on the water column (Islam, 2005;Sarà, 2007) and sediment quality (Holmer et al, 2003;Pusceddu et al, 2007) with detrimental consequences on the benthic communities (Tomassetti et al, 2009(Tomassetti et al, , 2016Edgar et al, 2010;Sanchez-Jerez et al, 2018).…”