Sponges in the continental shelf (73 – 210 m) of the southwestern area of Isla Fuerte and Alta Guajira, with the description of new records for the Colombian Caribbean

Abstract

The biodiversity of sponges in environments beyond 50 m is poorly known, as access to this type of environment without specialized technology is difficult. This study aims to understand the biodiversity of the group present on the continental shelf of the southwestern area of Isla Fuerte and Alta Guajira. Sponge samples were collected via trawls during exploration sessions in hydrocarbon blocks between 73 and 210 m, which were fixed and taken to the sponge collection of the Museum of Marine Natural History of Colombia (MHNMC) in 2012. Then, in 2022, these samples were processed and identified in the laboratory using standard methods. A taxonomic list is presented, with 89 taxa belonging to the classes Demospongiae and Homoscleromorpha, which are grouped in 16 orders, 33 families, 51 genera, and 45 species, out of which 10 are new records for the Colombian Caribbean. Only one species was identified for Alta Guajira, which could be attributed to a difference in substrate composition and to the fact that, in the Isla Fuerte sector, due to diapirism and gas emanation events in the continental shelf, there is a greater availability of food, which can support the composition of sessile benthic organisms such as sponges.