- 1 Defining Features
- 2 Habitat and Range
- 3 Fisheries Conservation and Concern
- 4 Closest Relatives
- 5 Example Species in Squatiniformes
- 6 Example Species in the Gulf of Maine
- 7 References
Defining Features[edit | edit source]
Squatiniformes, also known as Angel Sharks, are found only in salt water. Their pectoral fins are not fused to the rostrum but are large and extend to their rostrum, giving them a flat, ray-like look. Their eyes are at the top of their head (dorsal), but do not protrude. These fishes can grow up to 6.6 feet fully matured, yet can still camouflage themselves well on the seafloor with their light coloring and sand-like patterning. Their caudal fin is semi-elongated, with two dorsal fins emerging from tail. These Angle sharks also have a pair of short barbels on the end of their oval shaped snout.
Habitat and Range[edit | edit source]
Widely spread across the globe yet within smaller pocket regions, Squatinformes or as it's more commonly known- “Angel shark”- is heavily dispersed from the North Sea starting in Norway around the western shoreline of the United Kingdom and with in he Mediterranean Sea (Northern Africa, Italy, western edge of Turkey). However, these sharks may also be found along Eastern pacific, starting in western Alaska to the edge of the Chilean shore where it then wraps around to Brazil, then around the Cape of South Africa to Tanzania and eventually around the shorelines of Indonesia and the southern strip of Australia.
Though these pockets are in various parts of the globe, one thing remains common in each location: its marine temperate or tropical environment. The majority of Squatinformes are found in shallow water depth as shallow as 10 ft. They can also be found in mesopelagic habitats in kelp forests.
Fisheries Conservation and Concern[edit | edit source]
Many Angel sharks are critically endangered and/or threatened. The main cause for the decrease in population is bycatch (commercial) and release after being caught (recreational). Habitat disturbance is another factor adding onto this. There are many groups and networks that are trying to protect these species which has caused a population rebound in a few places around the world. Besides that, much more work needs to be done to further protect angel sharks.
Closest Relatives[edit | edit source]
[Pristiophoriformes + Echinorhiniformes]
Example Species in Squatiniformes[edit | edit source]
Japanese Angel Shark[edit | edit source]
Squatina japonica[edit | edit source]
Defining Features: The Japanese Angel Shark has no dorsal soft rays, dorsal spines, anal soft rays, or anal spines. The pectoral fins have rounded free rear tips and are broad. It has a shorter hypocercal tail. On the midline of its tail and back from dorsal fins to head and between its fin bases, it has rows of large spines. The body coloration is blackish brown with smaller pale and dark spots, but it has no ocelli or eye like spot.
Range & Habitat: It is a marine demersal species that live or are found near the seafloor in the sand. The Japanese Angel Shark is distributed in the Northwest Pacific Ocean of the coasts of Japan, Korea, and northern China. It is also found in the Yellow Sea.
IUCN Concern: This species is considered to be vulnerable. It can be found in local fish markets throughout Japan and Taiwan, but it is undetermined if they are the specified target of fisheries. The Japanese Angel Shark is frequently bycatch in gillnet and set fisheries, and it is caught in large amounts by demersal trawl fisheries. Its distribution areas, such as the East China Sea and Yellow Sea, have been overfished and continue to be despite bans.
Pacific Angel Shark[edit | edit source]
Squatina californica[edit | edit source]
Defining Features: This species has no anal spines, dorsal spines, anal soft rays, or dorsal soft rays. It is dorsoventrally flattened, but its pectoral fins are separated from its head despite their broad appearance. The Pacific Angel Shark also has five gill slits that are located ventrally. On its snout, this organism also has nasal barbels and flaps. This species is usually grey or dark brown with varying shades of black and brown splotches. The ventral surface is white.
Range & Habitat: The Pacific Angel Shark resides in the eastern portion of the Pacific Ocean from Costa Rica to southern Chile as well as the Gulf of California to Alaska. It is a marine demersal species that lives in a depth range of 3 m to 205 m, but it usually is located in 3 m to 46 m. This species is found on littoral areas and the continental shelf.
IUCN Concern: This species is labeled as nearly threatened. The Pacific Angel Shark used to be used as bait or discarded at sea until a commercial fishery, located in California, started to specifically target the species in the early 1970s. Eventually, a minimum size was suggested for gillnet fisheries that were targeting the species, but the population levels continued to decline. Landings were already declining before the minimum size was proposed which suggests that the species was already over-exploited. This species was also often caught by fisheries that targeted elasmobranchs in Mexico, and it is now absent in the Baja California Sur where fishermen used to be able to catch Pacific Angel Sharks regularly.
Example Species in the Gulf of Maine[edit | edit source]
Atlantic Angelshark (also known as sand devil)[edit | edit source]
Squatina dumeril[edit | edit source]
Defining Features: These fishes have large eyes, and usually dark brown coloration. They have the same basic shape as other squatiniformes, eyes at the top of their heads, semi-elongated caudal fin, two dorsal fins emerging from their tail, and a pair of short barbels on the end of their oval shaped snout. The sand devil's barbels are actually "U" shaped and a bit shorter than the average barbels on an angel shark.
Range & Habitat: The sand devil is native to a variety of locations, from the Northwest Atlantic coast near the Gulf of Maine and Massachusetts to all the way down to the Gulf of Mexico. This species has even been seen as far down as Columbia in northern South America. It's habitat being at the bottom of the seafloor, as squatiniformes are bottom dwellers, and is normally seen buried in the sediment.
IUCN Concern: The Atlantic Angel Shark is under "least concern" in the IUCN red list, and it's population is increasing. Sometimes, it is accidentally caught in the Gulf of Mexico, but that is not concerning to the population of these angel sharks as a whole.
References[edit | edit source]
Animal Diversity WebBase: https://animaldiversity.org/accounts/Squatina_californica/
Chondrichthyan Tree of Life: https://sharksrays.org/
I.U.C.N. Redlist: https://www.iucnredlist.org/species/39328/80671059