Longspine chimaera

3/5/2018

Source: Australian National Fish Collection, CSIRO.

TFUI is bringing you another chocolate-brown chimaera this week with the longspine chimaera (Chimaera macrospina). A large chimaera, they have deciduous skin and are uniformly that brown color we mentioned. #Finfact: The first dorsal-fin spine is generally taller than the dorsal fin (this is why they have their common name)! Maximum size of these animals is at least 75 cm total length (TL). These chimaeras have a long tail and mature males have short, trifurcated claspers. I know what you may be wondering: what are trifurcated claspers?! Good question- we didn't know either. So we looked up the definition of "trifurcated" and got "divide into three branches or forks" which makes sense when you look at the clasper.

The longspine chimaeras have been observed on the continental slope of both east and west Australia. In fact, these chimaeras have even been seen around Tasmania (Northwest). Like many chimaeras, they tend to stick to depths of 435-1,300 metres (m) and are more common below 800 m. Due to habitat and depth overlap, these chimaeras can are sometimes are taken as bycatch in benthic deepwater commercial trawls in their range. Two Queensland State-managed commercial fisheries, the Deep Water Fin Fish Fishery and the East Coast Otter Trawl fishery, overlap with this chimaera's range.

Like other chimaeras, we still have large gaps in what we know about them! We can only assume that they are most likely egg layers (oviparous). The IUCN has assessed this species 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.
Commercial fishery: The activity of catching fish and other seafood for profit.
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.
Claspers: Sexual reproduction organs found on male elasmobranchs and chimaeras.
Deciduous skin: the continuous, periodic or seasonal peeling of their scales/skin.
Dorsal fin: Fin located on the back.
IUCN: International Union for Conservation of Nature.

Oviparity/oviparous: Where adult Chondrichthyans lay eggcases (also known as ‘mermaid’s purses) and the baby develops inside the egg before hatching.
Trawl fisheries: Fisheries that pull a fishing net through the water behind one or more boats.