Ichthyofauna of the Selvagens Islands. Do small coastal areas show high species richness in the northeastern Atlantic?

Abstract

The Selvagens Islands are located in the northeastern Atlantic between the Canary Islands and Madeira Island. As a result of their small size, remote location and harsh sea conditions only a few studies have been conducted to describe their marine species diversity. We were able to identify 29 new coastal fish species, an increase of 33% in the ichthyofauna described for these islands (n = 88). There is a prevalence of species with tropical affinities and only 2.3% (n = 2) are endemic to Macaronesia. Considered a stepping-stone colonization vector from the nearest continental shore, as proposed by other authors for this region, the Selvagens Islands host 34.1% of the ichthyofauna described for the much larger Canary Islands (n species = 258, submerged area n SelvagensIs. = 2.3%) and 47.3% of the ichthyofauna described for the more distantly located Madeira Island (n species = 186, submerged area n SelvagensIs. = 17.9%). Interestingly, 6.8% (n = 6) of the species failed to bridge the gap between the Selvagens Islands and Madeira Island. Data collected so far showed no trend toward an increasing number of species with high dispersal capability. The Selvagens Islands are an example of a high coastal species diversity occurring even in very small areas of the northeastern Atlantic Ocean.

Contrasts in the marine ecosystem of two Macaronesian islands: A comparison between the remote Selvagens Reserve and Madeira Island

“…Expansion of the reserve would provide protection for coastal and pelagic species, as well as reducing by-catch of sea birds, marine mammals, and large pelagic fishes (e.g., tuna and billfishes) that frequent the area. In addition, the Selvagens may be an important biogeographical link between Madeira and the Canary Islands [ 60 ].…”

“…The results of this study reinforce patterns observed at smaller spatial scales within the Canary Islands [ 16 – 17 , 45 – 46 ], and are consistent with observations contrasting remote vs. inhabited marine ecosystems around the world [ 61 – 63 ]. The Selvagens harbor one of the last intact marine ecosystems in the North Atlantic, and maintains high coastal fish species diversity within a relatively small area [ 60 ]. The Selvagens Nature Reserve serves as a global model for what can be achieved elsewhere if species are protected and allowed to recover within their borders.…”

New Insights into the Occurrence and Toxin Profile of Ciguatoxins in Selvagens Islands (Madeira, Portugal)

“…As a result of the remote location of Selvagens Islands and the high anthropogenic pressures at Madeira, total fish biomass was estimated to be 3.2 times higher at Selvagens than at Madeira, and when considering only the fish top predators biomass it reach values 10 times higher at Selvagens [26]. Previous studies describing the marine fish diversity found that 34.1% of the ichthyofauna observed in Selvagens also occurs in the Canary Islands and 47.3% in Madeira Island [27].…”

Geopolitics and Marine Conservation: Synergies and Conflicts

“…The habitats are very well preserved as a unique example of pristine habitats in the Atlantic, with many species rare at the global scale (Friedlander et al, 2016). The archipelago is influenced by the general circulation of the North Atlantic surface currents, playing an essential role on larval dispersal of species from many geographical origins (Marine Conservation Institute, 2019) These islands are, therefore "stepping stones" for colonization of new areas (Almada et al, 2015).…”