Abundance and Diversity of Holothuroids in Shallow Habitats of the Northern Red Sea

Abstract

Holothuroid sea cucumbers are vital members of Coral Reefs and associated marine habitats and provide vital ecological services. In the southern regions of the Red Sea their populations have been decimated by overfishing. The main objective of this study was to test the hypothesis that the northern part of the Red Sea serves as an ecological refuge for the species threatened farther to the south. Accordingly, populations of sea cucumbers in 4 shallow sites south of Eilat, Israel (29 ∘ 33 00N 34 ∘ 57 14E), were repeatedly surveyed from November 2013 to April 2014. Overall 11 species were observed in these shallow sites. Their abundance and diversity differed significantly between sites, but not temporally. In sites in marine protected areas, with an intact fringing reef, diversity was high, with Holothuria edulis and Bohadschia sp. being the most common species. In areas with higher human use and characterized by rubble and scattered corals, diversity was low, and Actinopyga bannwarthi was the most common species. The observed abundance and diversity did not support the refuge hypothesis. These findings are discussed in relation to other surveys of abundance and diversity in similar habitats.

Growth, Survival, and Behavior of Early Juvenile Sandfish Holothuria scabra (Jaeger, 1883) in Response to Feed Types and Salinity Levels under Laboratory Conditions

“…Sea cucumbers are essential keystone species, bioturbators, and recyclers in many coastal ecosystems and provide vital and often overlooked ecological services in the habitats they occupy (Yuval et al 2014). They are a significant component of the marine ecosystem as they help in the local buffering of ocean acidification and can be hosts for different parasites and commensals (Purcell et al 2016).…”

Community structure of Echinoderms in littoral zone of the Red Sea Coast of Egypt

“…The holothurian species H. atra was recorded with relatively highest density 8 individuals/100m 2 in site (14) the relative abundance of this species was relatively high in site (2). This result can be related that these sites are good habitats for sea cucumber which characterized by mixed habitats of coral reef, seagrass, rocky and sandy shore (Yuval et al, 2014). The reef has many cracks and groove like channels separating the reef areas and extends from the reef surface to high depths, all that give well sheltered and refuge place from enemy (Ahmed, 2009).…”

“…Holothurians are one of the most important members of Red Sea ecosystem and influence the structure and functioning of coral reef ecosystems (Bakus, 1973). In the recent years the holothurian species have overfishing all over the Red Sea especially in southern part (Yuval et al, 2014). Ahmed (2009) recorded 18 different species of sea cucumber in the Egyptian coast in the Red Sea and Gulf of Aqaba.…”