The Smallspotted catshark (Scyliorhinus canicula), also commonly known as the Lesser Spotted catshark, and sometimes referred to as the Sandy dogfish, Rough Hound or Morgay (in Scotland and Cornwall), is a catshark belonging to the family Scyliorhinidae. It is found on the continental shelves and the uppermost continental slopes off the coasts of Norway and the British Isles south to Senegal and in the Mediterranean. It is found primarily over sandy, gravelly, or muddy bottoms from depths of a few meters down to 1,312 feet. It is one of the most common sharks among its range.
Family: Scyliorhinidae – Catsharks
Genus: Scyliorhinus
Species: canicula
Phylum– Chordata
Class– Chondrichthyles
Common Name– Ground Sharks
Family– Scyliorhinidae
Common Name– Catsharks
Genus– Scyliorhinus
Species– canicula
Status: IUCN Red List LEAST CONCERN
Average Size and Length: Hatchlings measure between 9-10 cm/3.5-3.9 inches. Mature males in the Mediterranean measure 39 cm/1.3 feet, and females 44 cm/1.4 feet. They are larger in the Atlantic and in the North Sea. The maximum recorded in the Mediterranean was 60 cm/2 feet. In the UK and North Sea, 100 cm/3.3 feet.
Average Weight: It can weigh more than 4.4 pounds.
Teeth and Jaw: There are labial furrows on the lower jaw only. The teeth are larger in males than in females; in addition, male sharks from West African waters have stronger, larger, and more calcinated jaws. The differences in mouth dimensions and tooth length between males and females, and between immature and adult males, could be due to different feeding habits or adaptations for reproductive behavior. Generally, the teeth in the lower jaw are larger than the teeth in the upper jaw. There is a long, pointed central cusp, with two surrounding (one on each side) miniscule cusplets. The rear teeth are comb-like or burr-like.
Head: The head and snout are blunt. There are greatly expanded anterior nasal flaps that reach the mouth, and cover shallow nasoral grooves. The eyes are large and cat-like.
Denticles: The dermal denticles are small, and thus the shark does not feel extremely rough. Use of dermal denticles to assist in feeding was first documented in the Smallspotted catshark.
Tail: The caudal fin is asymmetrical.
Demographic, Distribution, Habitat, Environment and Range: The Smallspotted catshark or Lesser Spotted catshark can be found in the northeast Atlantic in Norway, the British Isles to the Mediterranean, the Canary Islands, the Azores, Morocco, Sahara Republic and Mauritania to Senegal, and the Ivory Coast (63° N and 12° N). They can be found on the continental shelves and upper slopes on sediment from nearshore to 361 feet. On occasion they have been found at 1,312 feet. They are considered demersal.
Diet: They feed on small invertebrates like gastropods, crustaceans, cephalopods and worms. They also consume a variety of fish.
Dietary preferences change with age; younger animals prefer small crustaceans, while older animals prefer hermit crabs and mollusks. Feeding intensity is highest during the summer due to the higher availability of prey life. There aren’t any apparent differences between feeding habits of males and females, but consumption does vary with the size of the shark.
Juvenile Smallspotted catsharks feed by anchoring the prey item on the dermal denticles near their tail, and tearing bite-sized pieces off with rapid head and jaw movements, a behavior known as “scale rasping” (Southall, E.J., Sims, D.W. 2003. “Shark skin: a function in feeding. Proceedings of the Royal Society of London”. Series B-Biological Sciences, 270: 47–49).
Larger sharks will prey on the Smallspotted catshark.
Aesthetic Identification: The Smallspotted catshark or the Lesser Spotted catshark has a large (compared to other related sharks) and slender body covered in numerous small dark spots on a light background. The dorsal side is a greyish brown background. The ventral background is lighter. Sometimes there are scattered white spots, and also eight or nine dusky saddles may be unclear. The two dorsal fins are located towards the tail end of the body. The second dorsal fin is much smaller than the first dorsal fin. There are five pairs of gill slits with the last two overlapping the pectoral fins. The anal fin base is elongate and measures less than the interdorsal space.
Biology and Reproduction: They are oviparous. Egg cases are deposited in pairs year-round, but mostly November through July on seaweed. They hatch in 5-11 months, but mostly between 8-9 months. Females located off the Mediterranean coast of France lay their eggs from March to June and in December. In the waters surrounding Great Britain, egg laying occurs in spring with a gap between August and October. On the Tunisian coast, the sharks lay their eggs starting in spring, peaking in the summer and then slightly decreasing during Autumn.
The size of each egg case varies with the size of the female. They are smaller in the Mediterranean. Egg cases usually measure 4 cm/1.5 inches x 2 cm/.8 inches, without ever exceeding 6 cm/2.4 inches. The egg cases have long tendrils, which are used by the female to attach them to the macroalgae in shallow coastal waters. When the egg cases are deposited farther from shore, they are placed on sessile erect invertebrates. Typically, between 18-20 egg cases are released during each season.
Males reach sexual maturity with a length of about 37–49 cm/1-1.6 feet. Females reach sexual maturity with a length of 36-46 cm/1-1.5 feet, this relates to between 3-8 years and they live a maximum of 12 years.
The Smallspotted catshark is a shark that has been used in comparative analysis of gastrulation. One reason this shark is ideal is because it is found in very large numbers and it is the only known species that sharks of all development stages can be found in abundance throughout the year. Fertilization is internal, but eggs are laid at early stages of development, before the formation of the blastocoel. Once laid, they can go on developing normally in the laboratory, simply in oxygenated seawater. Also, the size and accessibility of the embryo is ideal. Five well-characterized stages can be distinguished between the onset of gastrulation and the beginning of neurulation (Mazan, S., Sauka-Splengler, T. 2004. “Gastrulation in the chondrichthyan, the dogfish Scyliorhinus canicula.” Gastrulation: from cells to embryo. Ed. Claudio D. Stern. Cold Spring Harbor Laboratory Press. New York, NY, p. 151–155).
Parasites of the small-spotted catshark include the copepod Lernaeopoda galei, monogeneans Leptocotyle minor and Hexabothrium appendiculatum, and larval anisakid nematodes.
Behavioral Traits, Sensing and Intelligence: Adults can be found in single sex schools. The young and hatchlings can be found in shallow water.
They are nocturnal, remaining motionless during the daytime hours and actively searching for prey at night.
A study published in 2014 at Exeter University showed that individual small-spotted catsharks have different personality traits. Some individuals are more sociable than others, some more aggressive, some more exploratory in nature (Jacoby, D.M.P., Fear, L.N., Sims, D.W., Croft, D.P. 2014, Oct 2. Shark personalities? Repeatability of social network traits in a widely distributed predatory fish. Behavioral ecology and sociobiology. Volume 68, Issue 12, pp 1995–2003.
Speed: More than likely slow-moving.
Smallspotted Catshark or Lesser Spotted Catshark Future and Conservation: They are currently of least concern. They are taken in many fisheries, then discarded later. Their rate of survival after being discarded is high; 98%. However, continued monitoring of landing and discarded data is important to avoid any future decline. Some populations are stable or are increasing. They are popular and hardy in aquariums. They breed in captivity.
Since 2003 there have been yearly releases of these sharks into the Gullmarn fjord in Sweden by the public aquaria Havets Hus in Lysekil. More than 90 sharks have been released since 2003, of which one was found in southern Norway 10 years after its release. This means that these sharks can reach at least an age of 14 years.
Currently, it is on low commercial value. In the recent past it was one of the species sold in English and Scottish fish and chip shops as rock salmon, rock eel, huss or sweet william. In other parts of its range it is occasionally baked or used in fish soup. Its hard skin has been used as a substitute for pumice, but because the catsharks have to be skinned before they can be filleted discourages commercial fishermen from catching the Smallspotted catshark.
Smallspotted Catshark or Lesser Spotted Catshark Recorded Attacks on Humans: They are not a threat to humans. SCUBA divers are able to approach the Smallspotted catshark but depending on the situation, the shark may quickly swim away when approached closer than about a meter.
Scientists also use this common species as a common subject in the study of various systems within the body including hormones, blood, and organs.