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Protect Our Seas
News and views from the world of marine heritage and conservation
Tiger sharks map seagrass meadows
Researchers have discovered a massive seagrass ecosystem , after fixing cameras and trackers to the dorsal fins of tiger sharks . Data collected by the sharks revealed what the researchers say is the world ’ s largest known seagrass ecosystem , stretching across up to 35,000 sq miles of Caribbean seabed .
The discovery extends the total known global seagrass coverage by more than 40 %, according to the Nature Communications study . Seagrass meadows have long been under-researched – estimates of their total global area vary wildly , and mapping is challenging . Such difficulties mean that seagrass meadows have to be verified or ‘ ground-truthed ’ at the site . But sending human divers to photograph vast tracts of ocean floor is logistically challenging and very slow .
Tiger sharks are a different story . The highly mobile animals are able to reach significant depths , have a large range and spend a lot of time in seagrass meadows , hunting rays , dolphins and turtles . They are also unburdened by human constraints such as needing a boat or reliance on calm conditions .
Between 2016 and 2020 , researchers fixed camera packages , equipped with satellite and radio tags , to the dorsal fins of seven sharks . They caught the animals using circle hook drumlines , which hook into the animals ’ jaws . It is the “ safest way to catch sharks ” and causes no long-term damage , said Oliver Shipley , a senior research scientist at Beneath the Waves , a marine science non-profit , and co-author of the report .
Turret torn from Valentine tank
Divers from the Isle of Purbeck Sub- Aqua Club have reported that a turret has been torn off one of Studland Bay ’ s Valentine Tanks . The amphibious tanks were being tested as part of an exercise called Operation Smash six weeks before D-Day when they sunk in April 1944 . Prof David Parham , a maritime archaeologist
at Bournemouth University , confirmed the reports , saying the turret was lying to the side of the tank and that there had been ‘ significant damage ’ to the body . The internal components of the tank had been exposed , meaning that precious artefacts inside were now vulnerable to further damage . “ We know from the 1980s when a number of the tanks were blown up in ordnance disposal exercises by the Navy that within them are the personal possessions and the equipment of the crew .
“ There are no other tanks that we are aware of that are still equipped as if they were invading Normandy in June 1944 .” A Dorset Police spokesperson confirmed it had received reports of the damage and that its marine engagement team was carrying out inquiries to establish what had happened . The damage is believed to have occurred between 24 and 28 September 2022 .
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