Spiny Dogfish (Squalus acanthias) & Smooth Dogfish (Mustelus canis)
Spiny dogfish are the most commonly known of the two-dogfish species that inhabit the coastal waters off New Jersey. In fact, both the spiny dogfish and smooth dogfish are two completely distinct species of shark that belong in two separate family classifications.
The Squalus family of dogfish are made up of smaller dogfish species found around all the oceans of the world, but spiny dogfish are known to be the largest species od dogfish. Other smaller dogfish species are commonly found in aquariums across America. Spiny dogfish are also referred to as mud shark, skittledog, Atlantic spiny dogfish and Pacific spiny dogfish. The spiny dogfish is widely found from north to south on both coasts of North America. The spiny dogfish is the most well-known of the dogfish shark species here in New Jersey as well, and are easily identified by the spiny and slightly venomous pair of barbs at the front of each of the shark’s two dorsal fins. Spiny dogfish look almost prehistoric, carrying dark green and white spots along ta field of dark gray and brown backs.
The other dogfish species found throughout New Jersey is the dusky smooth-hound shark or as they are commonly referred to by Garden State anglers; the smooth dogfish. This dogfish belongs to the Mustelus scientific family of shark. This shark, although biological cousins to the spiny dogfish, is of a different scientific family. Smooth dogfish lack the two spine barbs of their prickly cousins, but exhibit many of the same behaviors and environmental needs to survive. These sharks are also lighter in color than spiny dogfish and are commonly flanked with white and even occasionally yellow shading on the sides of their underbellies. Smooth dogfish are a lesser known shark species that, unlike the spiny dogfish, only inhabits the Atlantic Ocean.
Spiny dogfish were once known as one of the most abundant shark species in the world, but have seen a sharp decline in the last decade due to the commercial fishing industry and a booming overseas market for these smaller sharks. In New Jersey, the fishing on spiny dogfish is seasonally off limits because of the shark’s critically threatened status throughout the Garden State and other Mid-Atlantic states. The only time an everyday angler can hook a spiny dogfish is largely restricted to the summer. In other southern Atlantic regions of America spiny dogfish are caught in far out Atlantic waters and exported to the United Kingdom, serving as the main fare for the region’s famous dish of ‘fish and chips’.
Smooth dogfish have similar population decreases despite being a lesser known shark species. The management surrounding the sharks is not as strict as with other notable shark species, such as with the spiny dogfish. They are often sought after by anglers in the Atlantic alongside their distant spiny cousins, but do possess restriction limits in states where populations are lower and under threat. The overall population of smooth dogfish within their Atlantic range is more stable than that of the spiny dogfish, but there are no official population counts on either species.
Dogfish are two of the smallest species of sought after shark fished within North American waters. When fully mature, both the spiny and smooth dogfish grow to an overall average length of five feet long in females of the species, whereas and male members of dogfish average a length of three feet long before reaching sexual maturity. The size of either species of dogfish often varies on the climate of the shark’s environment. Larger individuals are found more often in temperate southern coastal zones and smaller species in colder water ecosystems off the northern seas of the Northeast and Pacific Northwest in spiny dogfish.
The teeth of the spiny dogfish are specialized in crushing and grinding prey into a seafood pulp which the shark can easily digest. Spiny dogfish track down crustaceans and bony fish across the ocean floor while also being opportunistic scavengers as well. The spiny dogfish can take advantage of any meal that happens to cross its’ path and are therefore easily lured onto a strong line in both deep and shallow water along either North American coast.
Smooth dogfish have a similar jaw structure to their spiny cousin, with the ability to crush unsuspecting food items into a manageable mouth full. They are less opposing to handle due to the lack of venomous dual spines and blunted teeth, making smooth dogfish generally harmless to humans. Also, easily lured to a fishing line, smooth dogfish are commonly caught by anglers along both coasts of the Atlantic in various environments.
Despite their small size, both species of dogfish are still members of the shark family and should therefore be respected both on and off the fishing line. Spiny and smooth dogfish are both equipped with blunted teeth that are still able to slice an unguarded line. Modestly heavy leaders should be set as deep as the sea floor due to the ground staking hunting style found in either dogfish species.
Scrap fish are the best option when baiting a line and either species can be caught from shore, out at sea, by boat or off a pier, if the angler desires. Wait patiently for the hook to firmly set before attempting to bring in a dogfish. Be extremely cautious of the spiny dogfish’s back spines at the front of both dorsal fins. Smooth dogfish lack this last-ditch defense, but each spiny dogfish carries a compact dose of venom in either spine that, although not deadly, can still be harmful to anglers and beachgoers alike and should be avoided at all costs.
Spiny dogfish are known to live to an astounding age of over 100-years-old. They could possibly have the longest gestation period of any animal within the animal kingdom, with female spiny dogfish carrying their young for between 18 and 24 months. Spiny dogfish finally reach sexual maturity between 18 and 20 years old in females and just 11 years old in males. When female spiny dogfish finally do give birth, they give birth to live young who are already a foot in length when born.
Female smooth dogfish reach sexual maturity at around four to five years old or when they reach a fully-grown length of five feet long; reaching reproductive maturity over four times faster than their spiny cousins. Male smooth dogfish reach sexual maturity two years and one foot shorter in length than females. The gestation period for smooth dogfish is shorter than spiny dogfish with a 12-month period before giving birth to live young measuring less than a foot long. Despite a faster sexual transformation, smooth dogfish are known to have a large gap between broods of pups, but when they do finally give birth smooth dogfish are known to give birth to over 20 pups at a time.
Spiny dogfish have highly adapted to a multitude of environments and are widely found on both sides of North America and abundantly off the coast of Western Europe. These smaller sharks are happily at home in deep water up to 700 feet far out to sea, or close by in the shallows just off shore. In New Jersey specifically, spiny dogfish are found along the state’s entire coast and have been observed and caught within the Delaware Bay as far inland as the mouth of the Delaware River. Spiny dogfish prefer murky temperate waters which make it easy for the sharks to conceal themselves and hunt or scavenge for food.
Smooth dogfish enjoy a similar habitat to their spiny cousins, but strictly inhabit the Atlantic Ocean and are among the species of shark that seasonally migrate. They can be found from the Chesapeake Bay down to coastal South Carolina during the winter months and migrate north at the end of spring to the Mid-Atlantic and Northeastern states. That puts the best time to see a smooth dogfish in New Jersey between May and October. This species of shark is less adapted to colder waters and must pursue limited prey items due to solely inhabiting the Atlantic and not the Pacific Ocean as well. This forces them on seasonal migrations that bring this lesser known shark species far across both sides of the Atlantic.