Contents
Introduction
Dogfish shark is a type of shark that belongs to the Squalidae family. It is considered a primitive shark because it has several features that are similar to the ancient sharks that lived over 300 million years ago. In this article, we will explore the external anatomy of the dogfish shark, including its body shape, skin, fins, and teeth.
Body Shape
The body of the dogfish shark is elongated and tapered at both ends. It has a fusiform shape that allows it to swim quickly and efficiently. The shark’s body is covered in rough, sandpapery skin called dermal denticles. These denticles provide protection against predators and reduce drag when swimming.
Skin
The skin of the dogfish shark is grayish-brown and covered in dermal denticles. These denticles are arranged in a pattern that resembles tiny overlapping scales. The shark’s skin is also covered in mucus, which protects it from parasites and bacteria.
Fins
The dogfish shark has several fins that help it swim and maneuver through the water. It has two dorsal fins, one on the back and one closer to the tail. It also has two pectoral fins, which are located behind the gills and help the shark steer and turn. The shark’s caudal fin, or tail fin, is crescent-shaped and provides the majority of the shark’s propulsion.
Teeth
The dogfish shark has several rows of teeth that are constantly replaced throughout its lifetime. The front rows of teeth are used for grabbing and tearing prey, while the back rows are used for grinding and crushing. The shark’s teeth are sharp and serrated, making them highly effective at catching and consuming prey.
Head and Senses
The dogfish shark’s head is relatively small compared to its body size. It has a pointed snout and large eyes that are positioned on the sides of the head. The shark’s nostrils are located on the underside of the snout and are used for detecting odors in the water. The shark also has a lateral line system, which is a series of sensory organs that run along the sides of its body. These organs are used to detect vibrations and movements in the water.
Gills and Respiration
The dogfish shark breathes through five to seven pairs of gills, which are located on the sides of its head. The gills extract oxygen from the water and expel carbon dioxide. The shark must constantly swim in order to keep water flowing over its gills and maintain respiration.
Reproduction
The dogfish shark is oviparous, which means that it lays eggs. The female shark produces several egg cases that contain a single embryo each. The egg cases are leathery and have tendrils that attach them to seaweed or other structures. The embryos develop inside the egg cases and hatch after several months.
Habitat and Distribution
The dogfish shark is found in temperate waters around the world. It prefers to live in deep water, but can also be found in shallow coastal areas. The shark is a bottom-dweller and feeds on a variety of prey, including fish, squid, and crustaceans.
Conservation Status
The dogfish shark is not currently listed as endangered, but some populations have been overfished for their meat and liver oil. The shark is also caught as bycatch in commercial fishing operations.
Conclusion
In conclusion, the dogfish shark is a fascinating and unique species of shark. Its external anatomy, including its body shape, skin, fins, teeth, head, senses, gills, and reproductive system, all contribute to its survival in the ocean. While the shark is not currently endangered, it is important that we continue to monitor its populations and protect it from overfishing and other threats.