Longnose chimaera

10/8/2017

Public Domain Jon Moore

The longnose chimaera (Harriotta raleighana) holds a special place in my heart… mainly because they were one of my MSc species!

The longnose chimaera is also known as spookfish or longnose rabbitfish with a relatively short, flattened nose. They are moderately sized (94-120 cm in length) and have a medium-sized eye above or behind their mouth. These chimaeras sport a tall first dorsal fin that has a spine in front; they also have large pectoral fins, and no anal fin. Their claspers are covered in fine spines, their pre-pelvic clasper is adorned with large thorns, and the head clasper has dense spines on its surface. It doesn’t seem like a good recipe for sex, but clearly they like it.

They are uniformly chocolate brown in colour, with paler fins that are darker at the edges. They also have deciduous skin, and are often pale when skin falls off. Attaining 94 – 120 cm in length, their diet is made up of shellfish and crustaceans.

They are found on the continental slopes of the Atlantic, Indian and Pacific Oceans up to 2600 metres (m) deep. The longnose chimaeras are occasionally caught as bycatch on continental slopes of New Zealand (part of my MSc thesis!) from deep water fisheries, and often marketed for their meat. The IUCN has currently assessed them as Least Concern (LC).

have you seen these animals?

glossary

Bycatch: The part of a fishery’s catch that is made up of non-target species.
Continental shelf: Extends from a continent underwater, resulting in a shallow-water area.
Continental slope: The steep slope from a continental shelf to the ocean floor; usually around 20 km (12.4 miles) wide and made up of mud and silt substrate. It is an ideal area for deep sea fishing.
Deciduous skin: the continuous, periodic or seasonal peeling of their scales/skin.
Dorsal fin: Fin located on the back.
Head clasper: male chimaeras have cephalic claspers (tenacula) on their heads; thought to aid in holding the female during mating.
IUCN: International Union for Conservation of Nature.
Pectoral fins: Fins located behind the gills on either side.
Pre-pelvic claspers: closer to the head than pelvic claspers.