Revised species records reveal the Canary Islands as a cephalopod biodiversity hotspot

Abstract

Cephalopods are a diverse group of species, with a high ecological and economic relevance. Despite this, its species diversity has been studied in few places at regional scale. We herein aim to update the current state of knowledge and diversity of cephalopods fauna of the Canary Islands. We carried out a systematic review of the available literature regarding cephalopod species in the area spanned from 1834 to 2019. More specifically, we reviewed (a) records of historic and recent research cruises; (b) records of species from scientific literature and technical reports; and (c) stomach contents analysis of top predators. A total of 48 documents, including scientific literature, technical reports, and species referenced in museums collections of cephalopods caught around the Canary Islands were identified. The current species richness in different habitats from coastal to deep-sea zones was determined according to records and previous information on the ecology of each species. These records revealed that this small archipelago holds 85 confirmed species belonging to 31 families, representing ca. 10% of the overall known cephalopod diversity. The cephalopod community was dominated by oceanic cephalopods, followed by shelf-slope and coastal cephalopods species with 65, 11, and 9 species, respectively. 47% of the species showed a wide geographic distribution (33 cosmopolitan and 7 presents in more than one ocean), whereas 19 are only encountered in the Atlantic Ocean and Mediterranean Sea and 26 are exclusively Atlantic. This species richness is comparable to other cephalopod biodiversity hotspots, such as the Indian Ocean Ridge or the Caribbean. The Canarian cephalopod diversity likely to be underestimated, since scarce information exists on species inhabiting the deeper water layers around the Canary Islands. This work represents the first baseline of cephalopod biodiversity around the Canary Islands; hence, it constitutes a first step to develop future research on this taxonomic group.