Corals of the Aleutian Islands

Abstract

A unique feature of the benthic habitat in the Aleutian Islands is the presence of a highly diverse and abundant coral and sponge community. These communities likely provide important habitat for a variety of fish and invertebrate species. Summaries of historical data and recent direct observations with a submersible indicate that the Aleutian Islands may harbour the highest diversity and abundance of coldwater corals in the world. There are 69 documented taxa (species and subspecies) of coral in the Aleutians of which 25 are endemic. Within the Aleutian Islands, there is an increase in diversity of corals west of about longitude 169°W. This shift in diversity is consistent with the hypothesis of an ecological boundary in the vicinity of Samalga Pass. Given the endemism and high diversity and abundance of corals in the Aleutians, there is evidence that this region is the evolutionary centre of origin for some taxa of coldwater corals.

NOAA Prof. Paper NMFS 16: The ecology of deep-sea coral and sponge habitats of the central Aleutian Islands of Alaska

“…Examination of specimens collected during that study, from fi shery surveys, and from fi shery bycatch revealed that the Aleutian Islands harbored a diversity of coldwater corals that was extraordinary for a high-latitude ecosystem and that at least 51 species or subspecies of hydrocorals and gorgonians were endemic to the region (Stone and Shotwell, 2007). Corals are widespread on the continental shelf and slope throughout Alaska, but strong evidence indicates that a major shift in coral abundance and species diversity occurs west of the Alaska Peninsula (Heifetz et al, 2005).…”

Megafaunal composition of cold-water corals and other deep-sea benthos in the southern Emperor Seamounts area, North Pacific Ocean

“…Ocean, and many other areas have shown that some species of cold-water corals build complex structures and produce unique demersal communities in the same way as do shallow-water coral reefs (Heifetz 2002;Heifetz et al 2005;Lundsten et al 2009;McClain et al 2010;Mol et al 2002;Morris et al 2013;Reed et al 2006;Roberts et al 2006;Stone et al 2015). Such frameworks of coldwater corals provide habitats or spawning and nursery grounds for fish and many other animals and thereby support diverse ecosystems (Baillon et al 2012;Roberts et al 2006).…”

“…Recent developments in deep-sea surveys that use acoustic and submersible devices have revealed the widespread distribution of cold-water corals on the deepsea floor throughout the world ocean (Heifetz et al 2005;Lundsten et al 2009;McClain et al 2010;Mol et al 2002;Reed et al 2006;Roberts et al 2006). Reports from…”

Unexpectedly High Diversity of Monoporella (Bryozoa: Cheilostomata) in the Aleutian Islands, Alaska: Taxonomy and Distribution of Six New Species

“…Supporting this contention is another group of benthic marine invertebrates that tends to occur in deeper water (most abundant from 100-200 m depth) (Stone, 2006) and that shows relatively high diversity analogous to that of Monoporella in the Aleutians. The species diversity of a diverse assemblage of skeleton-forming benthic cnidarians (the so-called "coldwater corals," including stylasterines, gorgonaceans, stoloniferans, pennatulaceans, alcyonaceans, and scleractinians) increases sharply west of Samalga pass (~169°W) (Heifetz et al, 2005). Several of these taxa have apparently undergone high levels of speciation in the Aleutians, resulting in a high number of endemics (Heifetz et al, 2005).…”

“…The species diversity of a diverse assemblage of skeleton-forming benthic cnidarians (the so-called "coldwater corals," including stylasterines, gorgonaceans, stoloniferans, pennatulaceans, alcyonaceans, and scleractinians) increases sharply west of Samalga pass (~169°W) (Heifetz et al, 2005). Several of these taxa have apparently undergone high levels of speciation in the Aleutians, resulting in a high number of endemics (Heifetz et al, 2005).…”