Distribution Patterns of Benthic Foraminifera in Fish Farming Areas (Corsica, France): Implications for the Implementation of Biotic Indices in Biomonitoring Studies

Abstract

Corsican marine aquaculture is one of the highest contributors of fish production in France, which may result in environmental perturbations caused by organic matter (OM) accumulation under fish farms and impacting natural communities. This study aimed to (1) characterise the environmental conditions at two different fish farms, (2) monitor the response of benthic foraminiferal species to this activity, and (3) assess the accuracy of existing foraminiferal biotic indices. In 2017, sea floor sediment was sampled in transects from two Corsican fish farms for living foraminiferal and sedimentary analyses. Four indices were calculated and compared: exp(H′bc), Foram-AMBI, Foram Stress Index and TSI-Med. A significant increase in total organic carbon (TOC) has been shown, mainly below the fish cages. Communities were characterized by a shift from high density, opportunistic and tolerant species under the cages to lower densities and more sensitive species further away. According to their distribution patterns along the TOC gradient, we propose to update the ecological group classification of seven species to improve Foram-AMBI’s accuracy and sensitivity: Triloculina oblonga and Quinqueloculina lamarckiana to Ecological Group (EG) I; Rosalina bradyi to EGIII; and Bolivina dilatata, Bulimina aculeata and Quinqueloculina stalkeri to EGIV. We recommend prioritising the use of TSI-Med and Foram-AMBI with the updated list to assess ecological quality in coastal waters of the Mediterranean Sea.

The Ecological Quality Status Assessment of Marine and Transitional Ecosystems: New Methods and Perspectives for the Future

“…Three contributions specifically focused on monitoring the health of benthic habitats. In detail, Dubois et al [20] considered the effects of fish farming in Corsica (France) in the Mediterranean Sea, Parent et al [21] tested different biotic indices in a large survey along the French coast of the Mediterranean Sea, and Filippos et al [22] assessed the effects of a sewage outfall in front of the nearshore beach of Cigarras in Brazil. All these studies highlighted the accuracy of foraminiferal biotic indices in evaluating EcoQS.…”

A Multiparametric Approach to Unravelling the Geoenvironmental Conditions in Sediments of Bay of Koper (NE Adriatic Sea): Indicators of Benthic Foraminifera and Geochemistry

“…Foraminiferal species are grouped in five ecological groups according to their sensitivity to organic matter enrichment (from the most sensitive GRI to the 1st order opportunists GRV, Table 1). For the calculation only species assigned to the ecological groups (Alve et al, 2016;Jorissen et al, 2018;Dubois et al, 2021;Parent et al, 2021) were used. The unassigned species are excluded from the data set before the proportion is calculated (Borja et al, 2000(Borja et al, , 2008.…”

Domestic Sewage Outfall Severely Altered Environmental Conditions, Foraminiferal Communities, and Ecological Quality Statuses in Front of the Nearshore Beach of Cigarras (SE Brazil)

“…Benthic foraminifera are abundant [25] and an important component of modern benthic communities, representing up to 50% of the benthic eukaryotic biomass [26], being a key link between microalgae and bacteria to the higher trophic levels [27,28] and playing a key role in bioturbation processes in soft-bottom sediments [29,30]. These organisms are sensitive to either natural or anthropogenic impacts (see review [31]), which constrain the assemblages composition, altering the abundance and diversity of organisms [22,32,33], leading to the formation of test anomalies [19,34,35], and favoring the development of opportunistic species due to their tolerance to pollutants and adverse environmental conditions [20,36,37]. Hence, foraminifera have been used to evaluate environmental impacts as sewage outfall [20,23,38,39], heavy metal [35,40], aquaculture [41,42], and petroleum hydrocarbon [43,44].…”