New research shows that oceanic shark and ray abundance has declined by nearly three-quarters since 1970, and industrialized fishing isto blame.
Oceanic sharks and rays live so far from land that the average person is unlikely to ever see them. But these species, which live in the vast open ocean, are also among the most revered, and include the great white shark and the giant manta ray. For millennia, their remoteness has allowed these species to largely avoid humans. But since the early 1950s, industrial-scale fishing fleets have been able to reach distant waters and gradually spread to exploit the entire global ocean.
Rising demand over the same period for shark and ray meat, as well as fins, gill plates and liver oil, has caused catches of the 30 or so oceanic species to soar. Marine biologists have been raising the alarm for several decades now, but their warnings were often limited to what regional trends showed. Now, new research has brought together disparate threads of data into a single, global analysis of shark and ray populations in the open ocean.
Worldwide, oceanic shark and ray abundance has declined by 71% since 1970. More than half of the 31 species examined are now considered to be endangered, or even critically endangered. Compare this with 1980 when only one species, the plankton-feeding basking shark, was thought to be endangered. These are stark statistics, and they indicate that the future for the oceans top predators is fast deteriorating.
To arrive at the first global perspective on oceanic shark and ray population trends, the study synthesized a huge amount of data. The researchers calculated two separate indicators of biodiversity, using indexes established by the Convention on Biological Diversity to track progress towards international targets. They used state-of-the-art modeling to estimate trends in the relative abundance of species. One of the indicators combined assessments of 31 species by the IUCN Red List over a 38-year period.
The results revealed huge declines in the abundance of sharks in the Atlantic, Indian and Pacific oceans. Once abundant species such as the oceanic whitetip shark have declined by 75% globally in just the past half-century, while populations of the endangered shortfin mako shark valued for its meat and fins have shrunk by about 40%. Manta ray populations have suffered even greater losses.
The study attributes these declines to overfishing. The researchers documented a greater than twofold increase in fishing pressure from longline fisheries for instance, which use lines stretching 100km and bearing 1,200 baited hooks. These lines are deployed each day by any one of the thousands of longlining vessels worldwide, snaring sharks in the open ocean either intentionally or as bycatch while targeting other marine life.
The study also found increases in the proportion of sharks that are being fished beyond sustainable levels. But its particularly worrying that unreported catches werent included in the studys analyses. This means the number of sharks and rays killed by fishing boats is likely to be an underestimate and the actual declines of these species may be even worse. Unlike most species of bony fish, sharks and rays produce few offspring and grow slowly. The rate at which they reproduce is clearly no match for current levels of industrialized fishing.
Immediate and far-reaching action is needed to rebuild these populations. Its clear that the rate of overfishing has outstripped the implementation of fisheries management measures and trade regulations. Since most oceanic sharks and rays are caught in the high seas areas beyond national jurisdictions agreements between fishing nations within management organizations are needed for conservation measures to work.
But, as this new study details, fishery limits imposed by management organizations of regional tuna fisheries bodies tasked with managing oceanic sharks and ray populations have been largely inadequate in following scientific advice. As recently as November 2020, the European Union and United States blocked a catch retention ban for North Atlantic shortfin mako sharks, despite scientific evidence clearly indicating that it was the first rung on a ladder to restoring this population of an endangered species.
To begin the recovery of oceanic shark and ray populations, strict measures to prohibit landings of these species and to minimize their bycatch in other fisheries are needed immediately. This must be coupled with strict enforcement.
Reducing the number of sharks and rays caught accidentally will be crucial but challenging, especially for longline fishing, which is not very selective and inadvertently catches lots of different species. This currently means that bans on intentional fishing are unlikely to be effective on their own. One solution would include modifying fishing gear and improving how fishers release sharks and rays after capture, to give them a better chance of survival.
An equally important measure, noted in the current study, would be banning fishing fleets from hotspots of oceanic sharks and rays. Research published in 2019 highlighted where these areas in the global ocean overlap with fishing vessels most. Led by the United N, negotiations are underway for a high seas treaty which would create no-take marine reserves to protect threatened species in the open ocean. This new study should urge the international community to take such action while theres still time.
This article is republished from The Conversation under a Creative Commons license. Read the original article.
Sharks: Imperiled, Maligned, Fascinating
Link:
The Staggering Decline of Oceanic Sharks and Rays The Revelator - The Revelator
- High Seas Forecast (Tropical Atlantic) - December 8th, 2016 [December 8th, 2016]
- U.S. High Seas Marine Text Forecasts by Area - December 10th, 2016 [December 10th, 2016]
- Global High Seas Marine Preserve A non-profit dedicted ... - February 2nd, 2017 [February 2nd, 2017]
- New centre for high seas visitors in Angus - The Courier - The Courier - February 11th, 2017 [February 11th, 2017]
- Naval Presence on High Seas Underscored - Financial Tribune - February 11th, 2017 [February 11th, 2017]
- Pirates Face Push Back On The High Seas - American Media Institute - February 12th, 2017 [February 12th, 2017]
- Queen Mary 2 to Host High Fashion on the High Seas - Cruise Hive - Cruise Hive - February 13th, 2017 [February 13th, 2017]
- Nigeria Rescues Oil Tanker From High-Seas Pirates - OilPrice.com - February 13th, 2017 [February 13th, 2017]
- Cabin cam shows the hilarious frustration of rolling on the high seas - Pickle - February 13th, 2017 [February 13th, 2017]
- Ransomware Gangs Have Become the High-Seas Pirates of the Internet - On the Wire (blog) - February 13th, 2017 [February 13th, 2017]
- Suspect in high-seas homicides hospitalized, putting case on hold - Sacramento Bee - February 15th, 2017 [February 15th, 2017]
- Gargrave Pantomime Group hit the high seas with Sinbad the Sailor - Craven Herald - February 16th, 2017 [February 16th, 2017]
- Sailing the high seas: Top cruises for first-timers, families and excursions in 2017 - Malay Mail Online - February 16th, 2017 [February 16th, 2017]
- The Cold War returns to the high seas (opinion) - CNN.com - CNN - February 16th, 2017 [February 16th, 2017]
- All aboard for Cosplay on the high seas, Latest Travel News - The ... - The New Paper - February 17th, 2017 [February 17th, 2017]
- The Cold War returns to the high seas - CNN International - February 17th, 2017 [February 17th, 2017]
- Star-Studded Broadway on the High Seas 8 Sets Sail Feb. 17 - Playbill.com - February 17th, 2017 [February 17th, 2017]
- 'The internet is like the high seas' - Deutsche Welle - February 18th, 2017 [February 18th, 2017]
- Sailing the high seas - Fiji Times - February 18th, 2017 [February 18th, 2017]
- In Dramatic High Seas Rescue, Four Fishermen Rescued By Good Samaritans Off Galveston, Texas, Coast - Patch.com - February 18th, 2017 [February 18th, 2017]
- Greg McQuade discovers life on the high seas aboard USS Dwight D. Eisenhower - wtvr.com - February 18th, 2017 [February 18th, 2017]
- Escape to the high seas at the National Aviary - NEXTpittsburgh - February 22nd, 2017 [February 22nd, 2017]
- Ocean Prediction Center-Coastal, Offshore and High Seas ... - February 22nd, 2017 [February 22nd, 2017]
- Lagerstein hitting the high seas for Rum City - Bundaberg News Mail - February 23rd, 2017 [February 23rd, 2017]
- Scapa Flow German High Seas Fleet scrap sites explored - The ... - The Orcadian - February 24th, 2017 [February 24th, 2017]
- Two boats towed in harbor in high seas - Cayman Compass - February 24th, 2017 [February 24th, 2017]
- Take to the high seas with Condor Sailing Adventures - Pensacola News Journal - February 25th, 2017 [February 25th, 2017]
- Aging high-seas murder suspect out of hospital and back in court - Sacramento Bee - March 1st, 2017 [March 1st, 2017]
- Masters of the waves talk of high seas, thrills & spills - The New Indian Express - March 2nd, 2017 [March 2nd, 2017]
- Campbell River Sea Cadet off to England to hit the high seas - Campbell River Mirror - March 3rd, 2017 [March 3rd, 2017]
- Survival on the high seas (From The Northern Echo) - The Northern Echo (registration) - March 3rd, 2017 [March 3rd, 2017]
- Industry 4.0 on the High Seas - MarineLink - March 3rd, 2017 [March 3rd, 2017]
- New Pirates Of The Caribbean: Dead Men Tell No Tales Trailer Brings Us More Action On The High Seas! - LRM Online (press release) (blog) - March 4th, 2017 [March 4th, 2017]
- Eco-warriors meet government authority on Ballina's high seas - Echonetdaily - March 6th, 2017 [March 6th, 2017]
- Tech on the high seas: Fred Olsen IT chief chats cloud, connectivity and security - www.v3.co.uk - March 7th, 2017 [March 7th, 2017]
- Why newbie Drusilla is preparing for life on the high seas - The Wharf - The Wharf - March 7th, 2017 [March 7th, 2017]
- Bhang Travel Inc. Brings Cannabis Networking to the High Seas - PR Web (press release) - March 8th, 2017 [March 8th, 2017]
- Drama on the high seas: East Kilbride couple reveal dramatic rescue after boat sinks in Gulf - Scottish Daily Record - March 8th, 2017 [March 8th, 2017]
- Journey through the high seas - The Standard - March 10th, 2017 [March 10th, 2017]
- French, Irish yacht sailors survive high seas off Australia's coast - TRT World - March 10th, 2017 [March 10th, 2017]
- 3 Digital Marketing Lessons From a Lawyer Focused on the High Seas - Entrepreneur - March 11th, 2017 [March 11th, 2017]
- Captain Cannonball sails the high seas as a pirate - Destin.com - Destin Log and Walton Log - April 8th, 2017 [April 8th, 2017]
- No clean boats on the high seas | Kochi News - Times of India - Times of India - April 8th, 2017 [April 8th, 2017]
- Trekr Racing makes its debut on the high seas - Washington Blade - Washington Blade - April 8th, 2017 [April 8th, 2017]
- Real 'Pirate Women' On The High Seas Of Old | On Point - WBUR - WBUR - April 8th, 2017 [April 8th, 2017]
- Cruise Operators Continue to Hide Behind the Death on the High ... - Cruise Law News - April 8th, 2017 [April 8th, 2017]
- Cruise ship crime: Who's in charge of law and order on the high seas? - Star2.com - June 6th, 2017 [June 6th, 2017]
- Footprints: PERIL ON THE HIGH SEAS - DAWN.com - June 6th, 2017 [June 6th, 2017]
- You can gamble on the high seas out of Galveston, but it might not always be smooth sailing - Rare.us - June 6th, 2017 [June 6th, 2017]
- An Energy Shock from the High Seas - Wall Street Journal (subscription) - June 6th, 2017 [June 6th, 2017]
- Navy dispatched 52 flotillas to high seas in 8 years - Mehr News Agency - English Version - June 7th, 2017 [June 7th, 2017]
- Barker and Team Japan ruling the high seas - Royal Gazette - June 7th, 2017 [June 7th, 2017]
- Hitting The High Seas: US LNG Finds A Home - Seeking Alpha - June 7th, 2017 [June 7th, 2017]
- A U-Boat Strikes and Terror Follows on the High Seas - New York Times - June 7th, 2017 [June 7th, 2017]
- HOPE LARSON and REBECCA MOCK Hit the High Seas with KNIFE'S EDGE - Newsarama - June 8th, 2017 [June 8th, 2017]
- Geopolitics On The High Seas And In Today's Headlines | On Point - WBUR - June 8th, 2017 [June 8th, 2017]
- World Oceans Day Comes at a Critical Time for High Seas - Natural Resources Defense Council - June 8th, 2017 [June 8th, 2017]
- High seas force Durban beaches closure | Berea Mail - Berea Mail - June 9th, 2017 [June 9th, 2017]
- African states band together to defeat crime on high seas | News24 - News24 - June 10th, 2017 [June 10th, 2017]
- Handmade boat for the high seas - New Straits Times Online - June 12th, 2017 [June 12th, 2017]
- High Seas, High "C"s: "The Little Mermaid," at the Prospect Park Auditorium through June 18 - River Cities Reader - June 13th, 2017 [June 13th, 2017]
- 'Skull & Bones' takes open world online gaming to the high seas - Engadget - June 13th, 2017 [June 13th, 2017]
- The Electric, Driverless Revolution Is About to Hit the High Seas ... - Bloomberg - June 13th, 2017 [June 13th, 2017]
- Brazil Gets Ready to Fight on the High Seas and Sets Aside US$ 1.8 Bi for New Warships - Brazzil.com - June 16th, 2017 [June 16th, 2017]
- Skull and Bones is pure high seas sailing fun from Ubisoft - Critical Hit - June 16th, 2017 [June 16th, 2017]
- Disney PhotoPass coming to capture your high-seas adventure on Pirates of the Caribbean at Magic Kingdom - Inside the Magic - June 16th, 2017 [June 16th, 2017]
- Coast Guard unloads 18 tons of cocaine seized on the high seas - The San Diego Union-Tribune - June 16th, 2017 [June 16th, 2017]
- High seas inspire collection - Royal Gazette - June 17th, 2017 [June 17th, 2017]
- High Yields on the High Seas | Equities.com - Equities.com - June 20th, 2017 [June 20th, 2017]
- Spectacle on the high seas: The best boat races in the Caribbean - USA TODAY - June 20th, 2017 [June 20th, 2017]
- Taking the Fight to the High Seas with the Dutch Royal Navy - MMORPG.com (press release) (registration) (blog) - June 22nd, 2017 [June 22nd, 2017]
- Big waves close coastal walkway, but some still brave stormy seas - Taranaki Daily News - June 26th, 2017 [June 26th, 2017]
- Seniors make waves with high-seas whodunit - Simi Valley Acorn - June 26th, 2017 [June 26th, 2017]
- High seas adventures at the Hannibal Aquatic Center - Hannibal.net - June 26th, 2017 [June 26th, 2017]
- Come See the Value Opportunities I Saw on the High Seas - TheStreet.com - June 26th, 2017 [June 26th, 2017]
- High seas adventures at the Hannibal Aquatic Center - Columbia Daily Tribune - June 27th, 2017 [June 27th, 2017]
- Slovenia wins battle with Croatia over high seas access - BBC News - June 30th, 2017 [June 30th, 2017]
- Arbitration panel grants Slovenia access to high seas - Fox News - July 2nd, 2017 [July 2nd, 2017]
- High Seas Governance Must Take Account of Existing IMO Framework - Hellenic Shipping News Worldwide - July 14th, 2017 [July 14th, 2017]
- An app to track missing people on high seas - Times of India - July 14th, 2017 [July 14th, 2017]