Revealing the coral habitat effect on benthopelagic fauna diversity in the Santa Maria di Leuca cold‐water coral province using different devices and Bayesian hierarchical modelling

Abstract

Data from two experimental longline surveys and two video inspections carried out in Santa Maria di Leuca cold‐water coral province (Mediterranean Sea) during spring–autumn 2010 were used in order to compare the benthopelagic abundance and diversity between coral and non‐coral habitats and between different devices. The sampling was carried out in two types of habitat: a coral habitat with carbonate mounds and a non‐coral habitat characterized by intermound sea floor. A Bayesian hierarchical modelling approach to accommodate factors influencing community assemblages was used considering the number of species, the Shannon–Wiener diversity index and the two most abundant species represented by the European conger (Conger conger) and blackbelly rosefish (Helicolenus dactylopterus). A relevant effect of the habitat factor was observed for both the number of species and the diversity index, showing a higher species number and diversity index in the coral habitat than in the non‐coral habitat. Concerning the relevance of fixed effects from the model on the probability of observing non‐zero (positive) abundances, the devices considered, longline and baited lander, did not show different influence for either C. conger or H. dactylopterus. In the case of positive abundance, a relevant device effect was only observed for H. dactylopterus, showing higher abundances for longline than for baited lander. A habitat effect was detected, with positive abundances for both species in the coral habitat. This study proves that structurally complex habitats generated by cold‐water corals influence the distribution and diversity of the benthopelagic fauna, and that the use of different devices can provide complementary useful results. Increased knowledge about the role of cold‐water corals in the associated benthopelagic fauna could lead to better conservation of one of the most important hot spots of biodiversity in the Mediterranean Sea.

Deep-Water Cartilaginous Fishes in the Central Mediterranean Sea: Comparison between Geographic Areas with Two Low Impact Tools for Sampling

“…The use of different sampling system has been validated through the comparison of species composition and abundance determined with different tools. Baited lander efficiency has been compared to those of different fishing methods including trap and longline [21,27,38,39]. These studies suggest that baited lander can provide information on species assemblage and abundance comparable to those generate with traps and longline.…”

The spread of the non-indigenous species Bregmaceros nectabanus Whitley, 1941 (Osteichthyes: Bregmacerotidae) in the eastern Mediterranean

“…Stomach content analysis provides a contribution to biodiversity knowledge especially in the deep-sea (Capezzuto et al, 2019;2022) avoiding the issues related to traditional sampling gears, such as mesh net size, as suggested by Ali (2018) about the low catchability of B. nectabanus.…”

Deep-water species assemblages on the trawlable bottoms of the Central Mediterranean: Changes or not over time?

“…The geomorphological diversity of the basin is reflected in different habitat distribution on the shallow and deep bottoms affecting the abundances of the megafauna in the area (D'Onghia et al, 1998b;Capezzuto et al, 2019;Maiorano et al, 2010;D'Onghia et al, 2011;Capezzuto et al, 2018;Ricci et al, 2022).…”