Spotted ratfish • Hydrolagus colliei
{Hydrolagus = water hare; colliei = after 19th century naturalist M. Collie on the HMS Blossom}
Photo by Tristan Blaine
Identification
There is no chance of confusing this cartilaginous fish* with any other species found along the coast of British Columbia. The only member of the small Family Chimaeridae found in the Pacific Northwest, the unique-looking spotted ratfish is composed of odd conglomeration of features. Its bulbous head features a large snout, over-sized green eyes, and a rabbit-like face with plate-like teeth well suited to grinding up its shelled food. This prominent head contrasts against a long, tapering, rat-like tail, a tall dorsal fin preceded by a long venemous spine, and large pectoral fins that look (and move) more like wings. Adding to the oddity of this creature is the prominent lateral line that branches across the face, making the face look as if it is composed of panels, similar to welded sheet metal — an appearance that may be further enhanced by small spots lining these tributaries of the lateral line. The spotted ratfish's smooth, scaleless skin is a shimmery bronze with silver spots. From large snout to pointed tail, this fish reaches almost a meter in length.
Habitat & Range
The spotted ratfish can be found near the seafloor, particularly sandy-bottomed locations, from the intertidal to nearly 1000 m deep. While it is most common in moderate to deep depths and so is not commonly spotted by divers, it can be attracted to lights on wharves and docks at night and may also swarm in shallow sandy habitats. Its range extends from central Alaska to northern Mexico, with an isolated population at the northern end of the Gulf of California.
Human Uses
The liver of this and other chimaerids were once used to make machine oil, for purposes such as lubricated guns. While it is often caught as bycatch in commercial fisheries, the spotted ratfish is edible but not tasty: its flesh is described on FishBase as bland with an unpleasant aftertaste.
Intriguing Info
The spotted ratfish has a venemous spine that can cause painful wounds. Its plate-like teeth are apparently also capable of inflicting considerable damage. These teeth aid the fish in eating crunchy prey such as mollusks, echinoderms, and crustaceans. It also eats worms and fish.
The male spotted ratfish has extra appendages used to clasp the female during mating: a single grasping organ kept folded on the top of the head, and a clasper behind each pelvic fin. The female lays long thin egg cases.
iNaturalist
https://www.inaturalist.org/taxa/84182-Hydrolagus-colliei
Check out the following video to see this fascinating fish in action and to learn more about its unique physiology and interesting life history.
There is no chance of confusing this cartilaginous fish* with any other species found along the coast of British Columbia. The only member of the small Family Chimaeridae found in the Pacific Northwest, the unique-looking spotted ratfish is composed of odd conglomeration of features. Its bulbous head features a large snout, over-sized green eyes, and a rabbit-like face with plate-like teeth well suited to grinding up its shelled food. This prominent head contrasts against a long, tapering, rat-like tail, a tall dorsal fin preceded by a long venemous spine, and large pectoral fins that look (and move) more like wings. Adding to the oddity of this creature is the prominent lateral line that branches across the face, making the face look as if it is composed of panels, similar to welded sheet metal — an appearance that may be further enhanced by small spots lining these tributaries of the lateral line. The spotted ratfish's smooth, scaleless skin is a shimmery bronze with silver spots. From large snout to pointed tail, this fish reaches almost a meter in length.
Habitat & Range
The spotted ratfish can be found near the seafloor, particularly sandy-bottomed locations, from the intertidal to nearly 1000 m deep. While it is most common in moderate to deep depths and so is not commonly spotted by divers, it can be attracted to lights on wharves and docks at night and may also swarm in shallow sandy habitats. Its range extends from central Alaska to northern Mexico, with an isolated population at the northern end of the Gulf of California.
Human Uses
The liver of this and other chimaerids were once used to make machine oil, for purposes such as lubricated guns. While it is often caught as bycatch in commercial fisheries, the spotted ratfish is edible but not tasty: its flesh is described on FishBase as bland with an unpleasant aftertaste.
Intriguing Info
The spotted ratfish has a venemous spine that can cause painful wounds. Its plate-like teeth are apparently also capable of inflicting considerable damage. These teeth aid the fish in eating crunchy prey such as mollusks, echinoderms, and crustaceans. It also eats worms and fish.
The male spotted ratfish has extra appendages used to clasp the female during mating: a single grasping organ kept folded on the top of the head, and a clasper behind each pelvic fin. The female lays long thin egg cases.
iNaturalist
https://www.inaturalist.org/taxa/84182-Hydrolagus-colliei
Check out the following video to see this fascinating fish in action and to learn more about its unique physiology and interesting life history.
* While characterized as cartilaginous fish, the spotted ratfish and its relatives (the chimaerids) have characteristics of both bony and cartilaginous fish; for this reason they are considered as a link between the two groups.
References
Froese, R. and Luna, S. M. Hydrolagus colliei (Lay & Bennett, 1839) Spotted ratfish. FishBase. Accessed 03/11/2015.
Lamb, A. and Edgell, P. Coastal Fishes of the Pacific Northwest. Revised. (2010). Madeira Park, BC: Harbour Publishing. Pp. 40-42.
Lamb, A., and Hanby, B. (2005). Marine Life of the Pacific Northwest [electronic version]. Madeira Park, BC: Harbour Publishing.
Spotted ratfish. Monterey Bay Aquarium. Monterey Bay Aquarium Foundation. Accessed 03/11/2015.
Authors and editors of page
Kelly Fretwell (2015).
Froese, R. and Luna, S. M. Hydrolagus colliei (Lay & Bennett, 1839) Spotted ratfish. FishBase. Accessed 03/11/2015.
Lamb, A. and Edgell, P. Coastal Fishes of the Pacific Northwest. Revised. (2010). Madeira Park, BC: Harbour Publishing. Pp. 40-42.
Lamb, A., and Hanby, B. (2005). Marine Life of the Pacific Northwest [electronic version]. Madeira Park, BC: Harbour Publishing.
Spotted ratfish. Monterey Bay Aquarium. Monterey Bay Aquarium Foundation. Accessed 03/11/2015.
Authors and editors of page
Kelly Fretwell (2015).
