Research technician Erin Voigt, measures a juvenile shark, as part of the University of North Carolina Coastal Shark Survey Cruise, Morehead City, NC. Photo credit: Mike Waine.
Sharks belong to the class Chondrichthyes (cartilaginous fish) that also includes rays, skates, and deepwater chimaeras (ratfishes). Relative to other marine fish, sharks have a very low reproductive potential. The low reproductive rate is due to sharks slow growth, late sexual maturity, one to two-year reproductive cycles, a small number of young per brood, and specific requirements for nursery areas. These biological factors leave many species of sharks vulnerable to overfishing.
Sharks have internal fertilization and the embryo of most species spend their entire developmental period protected within their mother's body, although some species lay eggs. Females produce a small number (2 - 25) of large pups, which have an increased chance of survival due to their size. Adults usually congregate in specific areas to mate and females travel to specific nursery areas to pup. These nursery areas are discrete geographic areas, usually in waters shallower than those inhabited by the adults. Frequently, the nursery areas are in highly productive coastal or estuarine waters where abundant small fish and crustaceans provide food for the growing pups. These shallow areas have fewer large predators than deeper waters, thus enhancing the chances of survival of the young sharks.
Sharks are a vital part of ocean ecosystems all over the world. Scientists consider them to be a keystone species because they generally reside at the top of the food chain having a strong impact on other species either directly or indirectly. Removing or reducing shark populations in an area can cause an imbalance in the food chain and produce far reaching negative impacts. Because of this, the health of shark populations in an ecosystem is often an accurate indicator of the overall health of the system.
Commercial shark fishing effort is generally concentrated in the Southeastern U.S. and Gulf of Mexico. Commercial fishermen catch sharks using bottom longlines and gillnets. The Atlantic fishery targets both large coastal shark (LCS) and small coastal shark (SCS) species. Bottom longline is the primary commercial gear employed in the LCS and SCS fisheries in all regions. Gear characteristics vary by region, but in general an approximately ten-mile long bottom longline, containing about 600 hooks, is fished overnight. Skates, other sharks, or various finfish are used as bait.
Recreational fishing for Atlantic sharks occurs in federal and state waters from New England to the Gulf of Mexico and Caribbean Sea. In the past, sharks were often called "the poor man's marlin." Recreational shark fishing with rod and reel is now a popular sport at all social and economic levels, largely because of accessibility to the resource. Sharks can be caught virtually anywhere in salt water, with even large specimens available in the nearshore area to surf angler or small boaters. Most recreational shark fishing takes place from small to medium-size vessels. Makos, white sharks, and large pelagic sharks are generally accessible only to those aboard ocean-going vessels. Recreational shark fisheries are exploited primarily by private vessels and charter/headboats although there are some shore-based fishermen active in the Florida Keys.
Stock status is assessed by species complex for most coastal shark species and by species group for species with enough data for an individual assessment. A 2011 benchmark assessment of dusky (Carcharhinus obscures), sandbar (Carcharhinus plumbeus), and blacknose (Carcharhinus acrontus) sharks indicates that both sandbar and dusky sharks continue to be overfished with overfishing occurring for dusky sharks. Blacknose sharks, part of the SCS complex, are overfished with overfishing occurring. The Board approved the assessment for management use in February 2012, and NOAA Fisheries' Highly Migratory Species Division (HMS) is incorporating the results of the assessment as part of Amendment 5 to its FMP.
Porbeagle sharks were assessed by the ICCAT Standing Committee on Research and Statistics in 2009. The assessment found that while the Northwest Atlantic stock is increasing in biomass, the stock is considered to be overfished with overfishing not occurring.
The 2007 SouthEast Data Assessment Review (SEDAR 13) assessed the SCS complex, finetooth, Atlantic sharpnose, and bonnethead sharks. The SEDAR 13 peer reviewers considered the data to be the 'best available at the time' and determined the status of the SCS complex to be 'adequate.' Finetooth, Atlantic sharpnose and bonnethead were all considered to be not overfished and not experiencing overfishing.
SEDAR 11 (2006) assessed the LCS complex and blacktip sharks. The LCS assessment suggested that it is inappropriate to assess the LCS complex as a whole due to the variation in life history parameters, different intrinsic rates of increase, and different catch and abundance data for all species included in the LCS complex. Based on these results, NMFS changed the status of the LCS complex from overfished to unknown. As part of SEDAR 11, blacktip sharks were assessed for the first time as two separate populations: Gulf of Mexico and Atlantic. The results indicated that the Gulf of Mexico stock is not overfished and overfishing is not occurring, while the current status of blacktip sharks in the Atlantic region is unknown.
There is no assessment for smooth dogfish on the Atlantic coast. The first coastwide assessment and peer review is scheduled for completion in 2014.
In the mid-1980s, sharks were considered an underutilized resource and fishermen were encouraged to fish for them. Over the next few years, fishing effort increased considerably and the impact of unregulated harvest was beginning to take its toll on some shark species. In the early 1990s, the National Marine Fisheries Service (NMFS) implemented a Fishery Management Plan (FMP) for Sharks of the Atlantic Ocean to rebuild depleted stocks and protect healthy stocks from overfishing. In May 2008, the Atlantic States Marine Fisheries Commission adopted an Interstate Fishery Management Plan for Atlantic Coastal Sharks (August 2008) to complement federal management actions and increase protection of pregnant females and juveniles in inshore nursery areas. The FMP regulates 40 different species of coastal sharks found on the Atlantic coast, and includes Addendum I (see accompanying table).
Addendum I, approved in 2009, modified recreational possession limits for smooth dogfish and other species, allowed at-sea processing of smooth dogfish from March - June, and removed the two-hour net check requirements, which was determined to be ineffective at reducing bycatch. In 2012, the Commission's Coastal Sharks Management Board approved a 36 fish possession limit for sharks in the large coastal sharks (LCS) species group (silky, tiger, blacktip, spinner, bull, lemon, nurse, scalloped hammerhead, great hammerhead, and smooth hammerhead sharks) for 2013, consistent with the federal specifications.