Spotted ratfish belongs to order chimera, class condricthyes. It is a marine water fish. Whole body is pigmented with white spots. and has long rat like tail. male anf females have distinct apperance. Males have claspers for transfer of sperms to the female body.

1. SPOTTED RATFISH
Hydrolagus colliei
Saleha Asawar

2. UNIVERSITY OF CHAKWAL, PAKISTAN
Presented by: Saleha Asawar
20M-UOC/ZOL-38
Presented to: Dr. Syeda Nadia Ahmad
Course Title: Ichthyology
Semester 8th (2020-2024)
Department of Zoology

3. Discussion Points
1 2 3 4 5
Introduction
Taxonomy
Morphology Habitat
Diet
Reproduction
Behaviour
Unique
Adaptations of
ratfish
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4. Taxonomy
Kingdom: Animalia
Phylum: Chordata
Class: Chondrichthyes
Order: Chimaeriformes
Family: Chimaeridae
Genus: Hydrolagus
Species: H. colliei
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Taxonomy Hierarchy

5. Introduction to Spotted Ratfish
❑ The spotted ratfish is a chimaera found in
the north-eastern Pacific Ocean.
❑ These fishes have smooth skin
❑ Large Green eyes
❑ Rabbit like face
❑ Mouth with plate like grinding teeth
❑ Tail is tiny, propel their large winglike
pectoral fins for propulsion. (Didier etal,
2002)
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6. Morphology
❑ Spotted ratfish have distinct appearance.
❑ Body tappers toward the end of fish.
❑ Tail covers almost half length of the body.
❑ Prominent lateral line canals on scaleless skin.
❑ At leading edge of dorsal spine sharp venomous spine.
❑ Pectoral fins are triangular in shape with fleshy base.
❑ Male have club shaped processes located on the head.
❑ Male with slender claspers next to pelvic fins. (Didier etal, 2002).

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https://www.savalli.us/BIO370/Diversity/03.Chondrichthyes.html

8. Body Coloration
❑ Body of spotted ratfish is
brown or grey with the
hues of gold, green and
blue.
❑ White spots are scattering
on the body of fish.
❑ Resulting in appearance
of iridescence with silvery
sheen.
❑ Ventral surface is silver
and fins are grey. (Bester,
2017).
Up-close view of the rabbit-like head of the spotted ratfish. Photo © George Burgess

9. Dentition
• Unlike sharks, which have
sharp teeth that are easily
replaceable, spotted ratfish
teeth are plate-shaped,
mineralized, and permanent,
which assist them in
grinding their prey.
• Like many bony fishes, but
unlike its sister group, the
Elasmobranchii, the upper
jaw of the chimaera is fused
with the skull. (Huber etal,
2002)
http://www.chalk.discoveringfossils.co.uk/5%20RATFISH%20TERMINOLOGY.htm

10. Habitat
❑Residing in temperate waters, found
most commonly off the Pacific
Northwest.
❑Live near the bottom from the intertidal
zone to depths of 2,950 feet (900 m).
❑It prefers mud and rocky bottom
habitats.
❑As the distribution range moves
southward, the spotted ratfish is found in
progressively deeper waters, preferring
water temperatures of 45-48 °F (7-9 °C).
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https://sanctuarysimon.org/regional_docs/monitoring_projects/100373_Kramp_2012.pdf

11. Food Habits
❑ Ratfish locate prey primarily though
electroreception and smell.
❑ Swims slowly close to the bottom substrate
searching for clams, crabs, shrimps,
polychaetae worms, and small benthic fishes.
❑ Spotted ratfish are also documented
cannibals. (Bester, 2017).
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https://themarinedetective.com/2016/02/08/ra-ra-ratfish/

12. Reproduction in Spotted Ratfish
❑Ratfish are oviparous.
❑Spawning peaks in spring to autumn.
❑During this time female releases up to 2 fertilized eggs in the mud or sand
seabed every 10-14 days.
❑The extrusion process can last 18–30 hours and the actual laying can last
another 4–6 days.
❑The egg sack is leather-like, 12.7 cm (5. 0 in) long, and has a filament
connected to it which is used to attach it to the ocean floor when it is let go
by the mother.
❑Development of the egg can take up to a year. (Barnett, 2008).
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13. ❑When the young finally hatch, they are about 14 cm (5.5 in) in length and
grow, reaching 30 cm (12 in) in length their first year.
❑Male spotted ratfish have multiple secondary sexual characteristics,
which include paired pelvic claspers, a single frontal tentaculum, and
paired pelvic tentacula.
❑The pelvic claspers are located on the ventral side of the fish.
❑They protrude out from the pelvic fins and are responsible for the
movement of sperm to the oviduct of the female
❑The cephalic clasper (tentaculum) is a unique, club-like organ not found
in any other vertebrate. (Barnett, 2008)
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14. Unique Features of
Spotted Ratfish
Having characteristics of both Bony
and cartilaginous fishes.
Gill openings are like bony fish and
reproduce like sharks.
Skeleton are made up of cartilage so
called chimeras.
can generate absolute and mass-specific bite
forces comparable with other durophagous
elasmobranchs.
It has the highest jaw leverage of any
cartilaginous fish studied. (Bester, 2017)
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2
3
4
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15. Predators of the Spotted Ratfish
Six gill
Sharks
Tope
Sharks
Trematode
s
Pacific
halibut
Rockfish
lingcod
Seven gill
Sharks
Spiny
dogfish
Marine
mammals (Bester, 2017)

16. Economic Importance
Importance to
Humans
▪ Although it is not a targeted species taken as
bycatch by commercial fisheries and recreational
fisheries usually considered as trash fish.
▪ Generally avoided due to dorsal spine.
Danger to Humans:
• Not considered as dangerous to humans.
• Care should be taken while handling due
to dorsal venomous spine.
• Care should be taken while handling male
sharp clasper organs. (Bester, 2017).
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17. Behaviour
• Ratfish prefers to maintain a safe distance
from divers.
• They are usually not aggressive.
• If they feel their territory has been
invaded, they are able to inflict a mildly
toxic wound with their dorsal fin spines.
• .As they swim, they perform barrel
rolls and corkscrew turns, as if they are
flying. (Bester, 2017).
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https://www.reeflex.net/tiere/4714_Hydrolagus_colliei.htm

18. Conservation Status
• The spotted ratfish is currently listed as
“Least Concern” by the World Conservation
Union (IUCN).
• Currently there are no conservation
measures being taken for the spotted ratfish,
however in Oregon (US) trawlers use gear
to avoid bycatch and reduce pressure on the
ratfish populations. (Barnett etal, 2012)
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https://themarinedetective.com/2016/02/08/ra-ra-ratfish/

19. Summary
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• The spotted ratfish (Hydrolagus colliei) is a chimaera found in the
north-eastern Pacific Ocean. Often seen by divers at night in
the Pacific Northwest, this cartilaginous fish gets its characteristic
name from a pointed rat-like tail. While mainly a deep-water
species, it occurs at shallower depths in the northern part of its
range. The spotted ratfish is common in much of its range, not
typically eaten by humans, and is not commercially caught.

20. References
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▪ Didier, D. A., & Rosenberger, L. J. (2002). The spotted ratfish,
Hydrolagus colliei: notes on its biology with a redescription of the
species (Holocephali: Chimaeridae). California Fish and Game, 88(3),
112-125.
▪ Huber, D. R., Dean, M. N., & Summers, A. P. (2008). Hard prey, soft
jaws and the ontogeny of feeding mechanics in the spotted ratfish
Hydrolagus colliei. Journal of the Royal Society Interface, 5(25), 941-
953.

21. 21 Presentation title 20XX
▪ Bester, C. (2017, August 05). Discover fishes. Retrieved from Natural
Museum of Florida:
file:///C:/Users/FAIZAN%20COMPUTER/Desktop/Hydrolagus%20colliei%
20%E2%80%93%20Discover%20Fishes.html
▪ Barnett, L. A. K., Ebert, D. A., & Cailliet, G. M. (2012). Evidence of
stability in a chondrichthyan population: case study of the spotted ratfish
Hydrolagus colliei (Chondrichthyes: Chimaeridae). Journal of Fish
Biology, 80(5), 1765-1788.
▪ Barnett, L. A. (2008). Life history, abundance, and distribution of the spotted
ratfish, Hydrolagus colliei.

22. Thank you