Do intertidal Zostera noltei meadows represent a favourable habitat for amphipods? The case of the Kneiss Islands (Gulf of Gabès: Central Mediterranean Sea)

Abstract

The structure, diversity, spatial and seasonal distributions of amphipod assemblages associated with intertidal Zostera (Zosterella) noltei meadows were studied around the Kneiss Islands (central Mediterranean Sea). This site represents a site of international interest in terms of its ornithological diversity (Important Bird Area, Ramsar Site and SPAMI). The amphipod fauna was sampled at 32 stations in spring 2014. A total of 6,482 individuals belonging to 78 species and 22 families were identified; among these taxa, Lysianassa ceratina is new for the Tunisian amphipod inventory, whereas 25 species are identified for the first time in the Gulf of Gabès. The dominant species are Cymadusa filosa, Microdeutopus gryllotalpa, Gammarus insensibilis, Dexamine spiniventris, Monocorophium insidiosum, Elasmopus rapax, Melita palmata and Leucothoe incisa. Four amphipod assemblages are identified using MDS analysis. The distribution of amphipod assemblages is linked to several environmental factors, such as sediment type, organic matter content and distance from the shore, which is itself associated with a clear inshore–offshore gradient. Seasonal variations of the amphipod assemblage patterns at eight stations, sampled between April 2014 and January 2015, show a maximum abundance and diversity during summer and autumn, with a minimum in winter. These seasonal fluctuations may be related to many factors such as variations of climatic factors (e.g. temperature, salinity), the growth and production rates of Zostera noltei meadows and seasonal patterns in the life cycle of dominant species.

Estimation of Chlorophyll and Turbidity Using Sentinel 2A and EO1 Data in Kneiss Archipelago Gulf of Gabes, Tunisia

“…Large offsets in these linear regressions indicate the influence of bottom reflectance. Several oceanographic studies, biogeochemical, fisheries features [54], amphipods [55], faunal analysis [56] were carried out in the Gulf of Gabes and Kneiss islands. The results are temporary and not continuous over time, which is why the extraction and generation of an algorithm for the continuous quantification of water quality data is a necessity in these types of environment.…”

Ecological status assessment and non-indigenous species in industrial and fishing harbours of the Gulf of Gabès (central Mediterranean Sea)

“…The identi ed taxa were classi ed into six trophic groups according to the categories used by many authors (e.g A i et Jumars et al 2014;Mosbahi al. 2017Mosbahi al. and 2020.…”

“…However, there are few quantitative studies designed to examine soft-bottom communities and the impacts of NIS in soft sediment habitats (Travizi et al 2019). In Tunisia, the majority of benthic macrofauna studies have focused on macrobenthic communities of shallow coastal areas (i.e Khedhri et al 2014;Fersi et al 2018;Boudaya et al 2019;Mosbahi et al 2017Mosbahi et al , 2019Mosbahi et al and 2020.…”