This small shark is also known as the piked dogfish, skittledog, spotted dogfish, white-spotted dogfish, codshark, and thorndog. Its dorsal fin has spines that are mildly poisonous.
First and second dorsal fins nearly equal in size 4. Eyes large, oval-shaped, and catlike Biology Smooth dogfish. The second dorsal fin is approximately twice as large as the anal fin and positioned slightly anterior to the anal fin.
The lower lobe of the tail is rounded and much shorter than the upper lobe. The rear edge of the upper lobe has a deep notch near the tip. The smooth dogfish has a tapering, blunt snout and a spiracle behind each narrow eye. The range of the smooth dogfish overlaps that of the spiny dogfish Squalus acanthiashowever it is easy to distinguish the two species.
The spiny dogfish has one spine in front of each of the two dorsal fins while the smooth dogfish lacks dorsal spines. The main distinction between these two species is the number of vertebrae, with the subspecies M. Spiny dogfish have spines in front of each dorsal fin as shown above.
The tips of both dorsal fins are also more pointed in M. Coloration Coloration of the smooth dogfish varies from gray to brown with the underside a yellowish gray Dogfish shark white. It has the ability to change its coloration through the contraction of melanophores to camouflage with its immediate surroundings.
Newborn individuals possess a first dorsal fin that has dusky gray edges on the upper portion, the apex of the second dorsal fin also has dusky edges with a white rear edge and a tail fin edged in white below. These marking fade quickly, usually by the time the smooth dogfish has grown to two feet in length.
Dentition Dentition of the smooth dogfish differs greatly from other sharks which have sharp blade-like teeth. The small teeth of the smooth dogfish are flat and blunt, similar in both the upper and lower jaws. They are asymmetrical with a rounded apex or cusp. Large mature smooth dogfish has tooth crowns that are low, hiding the cusps.
The rows of functional teeth are used to crush and grind prey items rather than bite and tear as with other species of sharks.
Ventral view of head. Illustration courtesy Bigelow and Schroeder FNWA Denticles Along the body of the smooth dogfish, denticles are irregularly spaced and lance-shaped with two to six longitudinal ridges extending the entire length of the denticle.
Smooth dogfish showing juvenile coloration. Smooth dogfish reach maximum size at seven to eight years of age. Average size of this shark is approximately 48 inches TL cm.
Longevity data indicates females live to 16 years of age and males have a life span of 10 years. This species grows quickly, with males reaching maturity at two to three years of age inches TL cm and females at four to five years of age inches TL cm.
Food Habits As a scavenger and opportunistic predator, the nocturnal smooth dogfish feeds primarily on large crustaceans, including lobsters, shrimp, and crabs, as well as small fish and mollusks.
The flat, blunt teeth of the dogfish are used to crush and grind these prey items which have tough outer body coverings.
Small fish that are preyed upon by the smooth dogfish include menhaden Brevoortia tyrannus and tautog Tautoga onitis. Young smooth dogfish feed on small shrimps, polychaete worms, and crabs. Female smooth dogfish are capable to storing live sperm throughout the year, although it is unknown if this sperm can be utilized for fertilizing eggs.
The smooth dogfish is a viviparous species with a yolk-sac placenta and a placental connection between the mother and embryo. Following a gestation period of approximately months, a litter numbering as few as 4 and as many as 20 is born during late spring or early summer.
Larger females tend to have larger litters of pups. Upon birth, the pups are inches cm in length. Smooth dogfish with gray coloration along the body and a white underside. Parasites The nematodes Pseudoterranova sp.Dogfish is a primary fish used in Fish n Chips in England.
I don't remember my source on the below, but I use it and eat the doggies Cleaning shark (dogfish). The spiny dogfish has dorsal fins, no anal fin, and dark green spots along its back. The caudal fin has asymmetrical lobes, forming a heterocercal tail.
The species name acanthias refers to the shark's two spines. These are used defensively. If captured, the shark can arch its back to pierce its captor. Dogfish Sharks Order: Squaliform. Dogfish sharks are the second largest of shark orders with species.
Dogfish come in all shapes, sizes, and colors and they live in almost every ocean habitat and depth. D. Sillman; 7/17/ Dissection of the Spiny Dogfish Shark – Squalus acanthias Biology – Penn State New Kensington (D.
Sillman - adapted from ‘Laboratory Studies in Integrated Zoology’ by Hickman and Hickman). The patches of pores on the head in the areas of the eyes, snout, and nostrils are the openings of the Ampullae of Lorenzini. Discuss the function of the Ampullae of Lorenzini with your group.
Fertilization in the dogfish shark is schwenkreis.com copulation, one of the male's claspers is inserted into the cloaca of the female.
The sperm proceed from the clasper of the male. Dogfish Head Craft Brewery and Tasting Room is located in Milton, DE.
Dogfish Head Brewings & Eats and Chesapeake & Maine located in Rehoboth, DE and the Dogfish Inn in Lewes, DE.