Marine Life & Conservation
Seahorses stalk their prey by stealth
Photo: Brad Gemmell
Seahorses may appear slow and awkward but they are ferocious and ingenious predators, according to a new study.
The beautiful creatures are famously bad swimmers, but they have a secret weapon to sneak up on their prey.
Their peculiar snouts are shaped to create very few ripples in the water, effectively cloaking them as they creep up and pounce on tiny crustaceans.
To their victims, seahorses are more like sea monsters, say scientists from the University of Texas at Austin.
“The seahorse is one the slowest swimming fish we know of, but it’s able to capture prey that swim at incredible speeds,” said Brad Gemmell, author of the study in Nature Communications.
The prey, in this case, are copepods – extremely small crustaceans that are a favoured meal of seahorses, pipefish and sea dragons (Syngnathidae).
When copepods detect waves from predators, they jolt away at speeds of more than 500 body lengths per second – the equivalent of a 6-foot human swimming at 2,000 mph.
“Seahorses can overcome one of the most talented escape artists in the aquatic world,” said Dr Gemmell.
“In calm conditions, they catch their intended prey 90% of the time. That’s extremely high, and we wanted to know why.”
Seahorses dine by a method known as pivot feeding. Their arched necks act as a spring – allowing them to rapidly rotate their heads and suck their prey in.
But this suction only works at short distances. The effective strike range for seahorses is about 1mm. And a strike happens in less than 1 millisecond.
Until now, it was a mystery how such apparently docile creatures managed to get close enough to their prey without being spotted.
To find out, Dr Gemmell and his colleagues studied the dwarf seahorse, Hippocampus zosterae, which is native to the Bahamas and the US.
They filmed the movement of water around the fish in 3D using holography – a technique where a microscope is fitted with a laser and a high-speed digital camera.
They found that the seahorse’s snout is shaped to minimise the disturbance of water in front of its mouth before it strikes.
Above and in front of its nostrils is a “no wake zone” and it angles its head precisely to attack its prey.
Other small fish with blunter heads, such as the three-spine stickleback, have no such advantage, the researchers found.
“It’s like an arms race between predator and prey, and the seahorse has developed a good method for getting close enough so that their striking distance is very short,” said Dr Gemmell.
“People don’t often think of seahorses as amazing predators, but they really are.”
Source: www.bbc.co.uk/news
6 years ago, The Ocean Cleanup set sail for the Great Pacific Garbage Patch with one goal: to develop the technology to be able to relegate the patch to the history books. On 6 September 2024, The Ocean Cleanup fleet returns to San Francisco bringing with it System 03 to announce the next phase of the cleanup of the Great Pacific Garbage Patch and to offer you a chance to view our cleanup system up-close and personal.
We look forward to seeing you there.
To confirm your presence, please RSVP to press@theoceancleanup.com
PROGRAM
Join The Ocean Cleanup as our two iconic ships and the extraction System 03 return to San Francisco, 6 years and over 100 extractions after we set sail, to create and validate the technology needed to rid the oceans of plastic.
Our founder and CEO, Boyan Slat, will announce the next steps for the cleanup of the Great Pacific Garbage Patch. Giving you a chance to view our cleanup system and the plastic extracted.
Hear important news on what’s next in the mission of The Ocean Cleanup as it seeks to make its mission of ridding the world’s oceans of plastic an achievable and realistic goal.
Interviews and vessel tours are available on request.
PRACTICALITIES
Date: September 6, 2024
Press conference: 12 pm (noon)
Location: The Exploratorium (Google Maps)
Pier 15 (Embarcadero at Green Street), San Francisco, CA
Parking: Visit The Exploratorium’s website for details.
RSVP: press@theoceancleanup.com
Video & photo material from several viewing spots around the bay
We look forward to seeing you there!
ABOUT THE OCEAN CLEANUP
The Ocean Cleanup is an international non-profit that develops and scales technologies to rid the world’s oceans of plastic. They aim to achieve this goal through a dual strategy: intercepting in rivers to stop the flow and cleaning up what has already accumulated in the ocean. For the latter, The Ocean Cleanup develops and deploys large-scale systems to efficiently concentrate the plastic for periodic removal. This plastic is tracked and traced to certify claims of origin when recycling it into new products. To curb the tide via rivers, The Ocean Cleanup has developed Interceptor™ Solutions to halt and extract riverine plastic before it reaches the ocean. As of June 2024, the non-profit has collected over 12 million kilograms (26.4 million pounds) of plastic from aquatic ecosystems around the world. Founded in 2013 by Boyan Slat, The Ocean Cleanup now employs a broadly multi-disciplined team of approximately 140. The foundation is headquartered in Rotterdam, the Netherlands, and opened its first regional office in Kuala Lumpur, Malaysia, in 2023.
Find out more about The Ocean Cleanup at www.theoceancleanup.com.
A shark has been spotted approaching Royal William Yard in Plymouth, much to the surprise of swimmers, paddleboarders and onlookers.
With its distinctive dorsal fin cutting through the water, the sizeable shark swam along the coastline, before turning to head inland towards Firestone Arch at Royal William Yard. The appearance drew a crowd, who were captivated for more than an hour by the unusual sight – and it was all caught on video.
The shark is one of many expected sightings at Royal William Yard over the coming weeks… because today marks the start of Shark Month!
In reality, the ‘shark’ spotted along the Plymouth shoreline was actually a custom-made model, created by the team at Royal William Yard and sailed underwater by Caroline Robertson‑Brown from the Shark Trust, who donned scuba diving gear for the occasion.
The stunt took place to launch Shark Month in style and draw attention to the work of the leading international conservation charity, which is based in Britain’s Ocean City. Spectators were reassured that the water was safe and many entered into the spirit of the performance, swimming or sailing alongside the shark.
Shark Month will take place across Royal William Yard throughout July and will feature an extravaganza of art, entertainment and advocacy for everyone to enjoy. The packed programme of events starts with an art exhibition and ends with a trip on paddleboards with shark experts – with everything from a shark quiz to a Jaws screening in between.
Paul Cox, CEO of the Shark Trust, said: “There are often assumptions and misconceptions when it comes to sharks. This was certainly the case with the shark spotted at Royal William Yard! While the British coastline is home to many species of shark, this was not one of them. However, we’re thrilled it caught people’s attention, because seeing a shark is a special and memorable moment. That is precisely why we want to celebrate these incredible creatures, highlight the need for conservation, and ask for help to safeguard their future.”
For more information about Shark Month at Royal William Yard, visit the Shark Trust Website.
Images and video: Jay Stone
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