COASTAL SHARKS

 “Coastal Sharks” is a term used by the Atlantic States Marine Fisheries Commission (ASMFC) to describe a complex of 41 diverse species, ranging from the small and inoffensive Florida smoothhound through the predatory white shark and on up to the whale shark, the largest fish that swims, which feeds only on plankton.

The National Marine Fisheries Service (NMFS) has two “coastal shark” categories. Eleven species are designated “large coastal sharks,” while four others are deemed to be “small coastal sharks,” all of which are subject to recreational and commercial fisheries. Many of the species included in ASMFC’s “coastal sharks” complex may not be killed or retained in federal waters; NMFS designates such nineteen species “prohibited sharks.” Other species included in ASMFC’s “coastal sharks” complex, including the shortfin mako and common thresher, NMFS deems “oceanic sharks” even though some of them, in particular the common thresher, may regularly be caught within state waters.

Recreational Fishery

Recreational shark fishing is popular throughout the Atlantic seaboard.

In the northeast, particularly between New Jersey and Massachusetts, which is arguably the epicenter of the sport, most such angling takes place in federal waters, where the acrobatic and good-tasting shortfin mako is a prized quarry. However, there also are shark fishing opportunities in the region’s inshore waters, particularly in recent years, when large schools of menhaden have appeared and lingered off area beaches. Sharks, including a few common threshers weighing in excess of 500 pounds, shadow the menhaden schools, and give small-boat anglers an good opportunity to catch sharks as well. In addition, there is a growing contingent of surfcasters who shark fish from the beaches at night. Although such anglers occasionally catch large sharks, surf fishing for sharks in the northeast is almost always a catch-and-release proposition, as most of the fish that come within reach of the fishermen are protected species such as sandbar and sand tiger sharks, which may not be killed.

Farther south, where waters are warmer and offshore anglers have far more opportunities to catch fish such as marlin, sailfish, wahoo and various tunas, deep-water shark fishing is a much less popular activity. However, inshore shark fishing, whether from a boat, a pier or the surf, draws more fishermen than it does In the northeast. Although small coastal sharks dominate the southern fishery, the possibility of hooking into a very large shark is much better than it is farther north; a 1,780-pound tiger shark, which held the all-tackle world record for forty-one years, was caught from a South Carolina pier in 1964. Today, most large sharks caught, whether from pier, shore or boat, are released, and many serious shark anglers participate in NMFS Cooperative Shark Tagging Program. Information about such program can be found at http://nefsc.noaa.gov/nefsc/Narragansett/sharks/tagging.html.

Commercial Fishery

Commercial shark fisheries , like recreational shark fisheries, are very diverse and differ from region to region.

Pelagic longliners, sailing on weeks-long trips out of northeastern ports, often catch and sell oceanic sharks such as shortfin makos, porbeagles and common threshers incidental to their targeted catch of swordfish and tuna. Such longliners also have a significant bycatch, and significant dead discards, of unsalable species such as blue sharks or the badly overfished dusky.

The directed shark fishery, which landed about 600,000 pounds of large coastal sharks and 350,000 pounds of small coastal sharks in 2015, is prosecuted in the southeastern states. Its primary tool is the bottom longline, which generally consist of about 300 hooks, attached by short dropper lines or “gangions,” to a heavy monofilament main line more than three miles long. There is also a directed shark gillnet fishery which operates primarily from the east coast of Florida.

Range and Biology

Given the size of ASMFC’s Coastal Sharks complex, and even the smaller coastal shark categories maintained by NMFS, there are few common threads tying all of the species together, although some generalities apply.

All sharks are cartilaginous; they have no bones in their skeletal structure, which is composed, instead, of cartilage. That’s why the only remains of fossil sharks that are usually found are the teeth. In addition, sharks don’t have scales. Instead, their skin is covered with “dermal denticles,” literally “little skin teeth” that lay smooth against the shark’s body and allows it to easily slip through the water while moving forward, but feel very rough and abrasive—so abrasive, that they have been used as a sort of sandpaper—when rubbed the wrong way, from tail to head.

Species diversity of sharks increases as water temperatures warm. None of ASMFC’s coastal sharks thrives in truly cold water. However, the so-called “mackerel sharks,” including the white, porbeagle and mako, are mildly endothermic, meaning that they can raise their body temperatures a few degrees above that of the surrounding water, which allows them to be more effective in cool northern seas. Blue sharks and common threshers are also often found in water temperatures as low as the mid-50s (Fahrenheit). Despite such exceptions, both the “large coastal sharks” and “small coastal sharks,” as designated by NMFS, are more common in the lower Mid-Atlantic and South Atlantic regions than they are farther north, with the small coastal sharks seldom seen north of Delaware Bay.

Sharks are generally active predators, that feed on fish, squid and, in the case of some species, crustaceans of various sorts. Some, like the tiger shark, are generalists that will feed on anything from flounders and skates that they pick off the bottom to sea turtles and (when they can catch them) porpoises and other marine mammals. Some are more specialized; a large proportion of an adult white shark’s diet consists of seals and other marine mammals, although they are more than willing to feed on large fish when they are readily available. The two largest shark species, the whale shark and basking shark, feed only on plankton. But in general, sharks eat fish.

How sharks find their food also makes an interesting story. The phrase “smell blood in the water” has become a cliché, but is essentially true. Most sharks hunt, at least in part, by scent, which is why a “chum slick” that releases the blood, oils and flesh of oily fish such as menhaden or mackerel into the water is such an effective way to draw sharks to one’s boat. However, scent is only one of the senses that a shark uses to feed.

Sharks, like most fish, can detect vibrations in the water, which are the underwater equivalent of sound. Thus, the commotion caused by a school of feeding tuna will often draw sharks into the same area.

Sharks’ snouts also bear organs called “ampules of Lorenzini” which allow the sharks to detect the faint electrical fields given off by most forms of life. Thus, a hammerhead shark that swims close to the bottom, swinging its head from side to side, is acting much like a minesweeper searching a battlefield, although its target is not munitions, but rather the stingray or crab attempting to hide between a thin layer of sand.

A few sharks are even sight-hunters. That is particularly true of the white shark, which habitually hunts well below the surface, then surges up upon sighting a seal or other prey to strike at the rear section of its target and achieve a “mobility kill” that deprives such prey of movement and allows it to weaken and bleed out, allowing the shark to feed with a minimum of struggle.

For all of their differences, sharks are part of an ancient line. Modern sharks date back to the mid-Devonian period, nearly 400 million years ago; more primitive sharks date back another 25 to 50 million years, to the Ordovician, soon after the first fish began to appear in the fossil record.

Management

All shark fishing in federal waters is managed by NMFS, which requires both recreational and commercial shark fishermen to obtain a Highly Migratory Species (HMS) fishing permit. Vessels holding the HMS permit are bound to follow federal regulations even when fishing in state waters. Thus, although ASMFC manages coastal sharks, its actions are only binding on fishermen who do not hold a federal HMS permit. (Note, however, that should ASMFC ever adopt management measures that are more restrictive than those imposed by NMFS, the more restrictive regulations would apply to HMS permit holders fishing within state waters.)

ASMFC’s Interstate Fishery Management Plan for Atlantic Coastal Sharks was developed independently from the HMS management plan developed by NMFs. NMFS’ HMS management plan, unlike other plans governing federal fisheries, was not developed by a regional fishery management council. Instead, because the fish species included in such plan frequently cross jurisdictional boundaries, it is a so-called “secretarial” plan developed at the agency level with the advice of the various HMS advisory panels.

STOCK STATUS

Because the term “coastal sharks” encompasses so many species, the status of the stocks varies widely. Generally, the small coastal shark stocks are in better condition than stocks of the larger species. Of the four small coastal sharks, only one, the blacknose, is deemed to be overfished; that stock is not expected to be fully recovered until 2043.

Such a long rebuilding period illustrates the biggest problem facing biologists attempting to manage the shark fishery. Sharks are apex predators that tend to have long lives, mature late and reproduce slowly. That makes it difficult to prevent overfishing, and means that overfished stocks may take a long time to recover. Both the dusky and porbeagle shark stocks were so badly overfished, and recover so slowly, that rebuilding is expected to take 100 years; the target rebuilding date for both species is 2108. Sandbar sharks are expected to take a little less time to recover, with rebuilding scheduled for 2023, while the overfished scalloped hammerhead may present a best-case scenario, with complete rebuilding expected by 2023.

The good news is that some other species, including the often encountered blue shark and shortfin mako, are not overfished, and are believed to support sustainable fisheries.

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