On the diversity of amphipods inhabiting Sargassum as well as clear areas in Kuwait coastal waters, with an assessment of the effect of turbidity and notes on their abundance, composition, and distribution: a preliminary study

The distribution and abundance patterns of amphipods associated with Sargassum species were studied on a spatial scale along Kuwait’s coastal waters. Macroalgae, in particular Sargassum spp., are known to host a high biodiversity of marine fauna, particularly amphipods, when compared to non- Sargassum (“clear”) areas. Amphipods are an important component in the food web, being consumed by different stages of fish. Sargassum was sampled from four different stations in Kuwait’s waters to determine the amphipod species composition and density. Physicochemical parameters were measured at the time of sampling at each station, focusing on turbidity, as this can promote variation in the faunal distribution between areas, and it was the only non-biological factor showing a distinctive pattern between stations in this study. The objectives of this study thus were to describe the amphipod biodiversity in Sargassum communities and to measure the difference in diversity between Sargassum and clear areas, while concurrently taking into account the effect of turbidity. The most abundant amphipods represented were Pontocrates sp. (cf. arenarius (Spence Bate, 1858)), Ericthonius sp. (cf. forbesii Hughes & Lowry, 2006), Maxillipius rectitelson Ledoyer, 1973, and Podocerus mamlahensis Myers & Nithyanandan, 2016. Among the measured physicochemical parameters, only turbidity had a significant effect on the biodiversity of amphipods (F1,6=19.35, p=0.0046) with a negative relationship based on the general linear model test. The effect of Sargassum and non- Sargassum areas on amphipod diversity was statistically not significant (F1,6=3.35, p=0.117). Also, there was no interaction between turbidity and Sargassum /clear areas (F1,6=0.12, p=0.742). However, the diversity was observed to be higher in Sargassum areas of all stations as compared to their clear counterparts, except in Khairan during January 2016, where the situation was the opposite. The abundance was highest in low turbidity, particularly at Salmyia station, compared to the high turbidity conditions at the stations at Failaka and Green Island. The species composition differed as well, the number of species found being the highest in the Sargassum area of Salmyia Station and the lowest at Failaka Island (highest turbidity). Only Salmyia Station (low turbidity) contained 27 species in its Sargassum area, of which only few were present at other stations in both areas. Turbidity affected the diversity of amphipods, and diversity was higher in Sargassum areas at all stations except Khairan in January 2016, but that difference was not significant.