The Spiny Dogfish Shark

By: Harrison Augustine

Shark Research Definitions

Shark External Anatomy

  • First dorsal fin - it is also referred to as the cranial dorsal fin, the spine itself is supported basally by a rod of cartilage which is just right above the vertebrae.
  • Second dorsal fin - a median ventral fin that is situated right between the anus and the tail fin in fishes, it actually helps them to maintain stable equilibrium.
  • Caudal fin - it is a vertical fin, that is actually used for propulsion in locomotion. This fin is the tail fin.
  • Pelvic fin - it is a pair of fins that are located on the underside of the fishes body, attached to the pelvic girdle and helping to control direction.
  • Gill slits - a series of openings that are between the gill arches of a fish, through which water passes from any of the pharynx to the exterior, which is bathing the grills in the process.
  • Snout - it is a projecting nose and mouth of an animal, especially a mammal.
  • Claspers - a pair of appendages that are located under the abdomen of a male shark or ray, or even at the end of a male insect, and they are used to hold the female during copulation.
  • Pectoral fin - each pair of fins situated on either side just behind a fish's head, which helps to control the directions of they're movement during locomotion.
  • Lateral fin - a series of sensory pores along the head and sides of fish and some amphibians by which water currents, vibrations, and pressure changes are detected.

Shark Internal Organs

  • Liver - the large lobed glandular organ located in the abdomen of vertebrates, involved in many metabolic processes.
  • Heart - an organ which includes the atrium and the ventricles. the heart pumps the blood supply throughout the body.
  • Kidney - organs that filter urea/waste from urine and rectum urea to the blood.
  • Gallbladder - an organ that is known as the green gallbladder and sits along the right edge. When not working properly, it can be very painful.
  • Pancreas - a large gland behind the the stomach that happens to secrete the digestive enzymes into the duodenum.
  • Small Intestine - a part of the intestine that runs right between the stomach and the large intestine; the duodenum, jejunum, and the ileum collectively.
  • Large Intestine - it is mostly know as the cecum, colon and rectum collectively.
  • Pancreas - an organ located near the duodenum and lower stomach. The pancreatic secreations enter the duodenum thorugh the pancreatic tube.
  • Stomach - it is an internal organ in which the major part of the digestive system occurs.
  • Esophagus - the part of the alimentary canal that connects the throat to the stomach; the gullet.
  • Rectum - the final section of the large intestine terminating at the anus.
  • Claspers - male anatomical found in some groups of animals for mating.
  • Lateral line - a system sense organs found in aquatic vertebrates used to detect movement and vibration in surrounding water.
  • Gills - the paired respiratory organs of fishes, and some amphibians by which oxygen is extracted by water flourishing other surfaces within or attached to the walls of the pharynx.
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Kingdom: Animalia

Phylum: Chordata

Class: Chondrichthyes

Order: Squaliformes

Family: Squalidae

Genus: Squalus

Species: Spiny dogfish shark

Life Span

They live about 18-24 months after winter and mating.


The spiny dogfish shark happens to stay in water between 45 - 59 degrees F. It will usually venture into brackish waters. Dogfish are mostly bottom-dwellers, dwelling in the depths from the surface down to 400 fathoms. (2,400 feet).
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