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. Commercial LCS landings in 2013 were approximately 434,300 pounds (dressed weight), a slight decrease from 2012, while landings of SCS species in 2013 were approximately 260,140 pounds (dressed weight), a decrease of approximately 38% from 2012, which is largely attributed to a decrease in Atlantic sharpnose landings. Total U.S. landings of Atlantic pelagic species of sharks were 257,900 pounds (dressed weight) in 2013, a 17% decrease from the average 2010-2012 landings.
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. The SCS complex dominated recreational landings of sharks in 2013 with 59,277 fish harvested. This is approximately 83% of the total recreational harvest. The LCS complex, including hammerheads, came next with approximately 2,528 fish harvested in 2013.
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. The Southeast Data Assessment Review (SEDAR) assessed the smoothhound shark complex in 2015. The complex contains two distinct stocks, one in the Atlantic region – smooth dogfish (Mustelus canis) – and one in the Gulf of Mexico – Florida smoothhound (Mustelus norrisi) and Gulf smoothhound sharks (Mustelus sinusmexicanus). The assessment results indicate the status of the Atlantic smooth dogfish is not overfished and overfishing is not occurring and the status of the Gulf of Mexico smoothhound shark complex is not overfished and overfishing is not occurring.
Based on a 2013 SDAR assessment, Atlantic sharpnose are considered not overfished and overfishing is not occurring, while the bonnethead stock status is unknown. The stock assessment panel pointed out that there may be two separate stocks of bonnethead, so in the future there should be two separate assessments. Based on a 2007 assessement by SEDAR, finetooth were found to not overfished and not experiencing overfishing.
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 Coastal Sharks Management 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 5a 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.
SEDAR (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, NOAA Fisheries changed the status of the LCS complex from overfished to unknown. As part of SEDAR, 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.
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 (see accompanying table).
Addendum I, approved in 2009, modified recreational possession limits for smoothhound 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. Addendum II and Addendum III (2013) addressed changes in the federal management of coastal sharks. Addendum II allocated state-shares of the smoothhound dogfish coastwide quota, and modified the maximum fin-to-carcass ratio, consistent with the Shark Conservation Act of 2010. Addendum III created two new species groups (Hammerhead and Blacknose) and increased the recreational size limit for hammerheads.
Based on the recommendation of its Coastal Sharks Technical Committee, the 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 2015. The Board’s action complements the proposed federal shark specifications.
The Shark Conservation Act of 2010 instituted additional measures to protect shark species from illegal, unreported, and unregulated fishing activities while protecting the sustainable fishing practices of domestic shark fishermen. In 2013, several states initiated or passed shark fin bans, which prohibited the possession of unattached shark fins. NOAA Fisheries released a proposed rule to preempt these state shark fin bans, as they interfere with the agency’s ability to sustainably manage shark fishing in domestic waters. Currently, NOAA Fisheries is working with each state to ensure adequate protection of sharks and optimum sustainable yield from shark fisheries.