Hermissenda opalescens
Distribution
Description
Previously thought to be Hermissenda crassicornis and now understood to be a separate species occuring from the Sea of Cortez to Northern California. The two species overlap in distribution in the San Francisco Bay Area. Distinguished from H. crassicornis by absence of longitudinal white band extending along anterior surface of each ceras. Like H. emurai (ranges from Japan to Russian Far East), cerata have brown to orange background colour and may or may not exhibit red or brown tip. Body is tarnslucent or white and longitudinal stripe between rhinophores is bright or light orange.
Information
Max Size: N/A cm
Sea Temperature Range: N/A
Depth: N/A
Habitat Generalization Index: N/A
Also referred to as the SGI (Species Generalisation Index), this describes the habitat niche breadth of the species. Species with values less than 15 are found in a relatively narrow range of reef habitat types (specialists), while those over 25 may be found on most hard substrates within their range (generalists). Learn more here.
Conservation and Rarity
IUCN Status: Not Evaluated
Occurrence: Common (33.3% of sites)
Occurrence describes how often the species is found on surveys within its distribution. It is calculated as the % of reef sites surveyed by RLS divers across all the ecoregions in which the species has been observed
Abundance: Several (6 per transect)
Abundance is calculated as the average number of individuals recorded per RLS transect, where present.
Edit by: Jo Schmid