Showing posts with label manta conservation. Show all posts
Showing posts with label manta conservation. Show all posts

Thursday, May 17, 2012

Satellite Tracking of Manta Rays Highlights Challenges to Their Conservation

We just finished reading an amazing paper on Manta birostris (thanks Gabriel Fava) written by Rachel T. Graham, Matthew J. Witt, Dan W. Castellanos, Francisco Remolina, Sara Maxwell, Brendan J. Godley, Lucy A. Hawkes.

For fans of in depth research data on very cool critters this is as good as it gets.

Manta gill rakers are another in a series of culinary and medicinal treats sent to Asia and the market is growing putting pressure on these magnificent animals.

Abstract

We describe the real-time movements of the last of the marine mega-vertebrate taxa to be satellite tracked – the giant manta ray (or devil fish, Manta birostris), the world’s largest ray at over 6 m disc width. Almost nothing is known about manta ray movements and their environmental preferences, making them one of the least understood of the marine megavertebrates.

Red listed by the International Union for the Conservation of Nature as ‘Vulnerable’ to extinction, manta rays are known to be subject to direct and incidental capture and some populations are declining. Satellite-tracked manta rays associated with seasonal upwelling events and thermal fronts off the Yucatan peninsula, Mexico, and made short-range shuttling movements, foraging along and between them. The majority of locations were received from waters shallower than 50 m deep, representing thermally dynamic and productive waters. 


Manta rays remained in the Mexican Exclusive Economic Zone for the duration of tracking but only 12% of tracking locations were received from within Marine Protected Areas (MPAs). Our results on the spatio-temporal distribution of these enigmatic rays highlight opportunities and challenges
to management efforts.


Complete paper here.

Tuesday, July 27, 2010

A Ray of Hope for Manta Rays in Brazil

Dr Andrea Marshall, also known as Queen of the Mantas from the BBC’s 2009 documentary film, has attached a satellite tag to a giant 4meter manta ray off the coast of South America. This ambassador for Brazilian manta ray conservation is the first manta ray in the Southern Atlantic Ocean to be satellite tagged and another first for Andrea, who originally discovered and tagged this second species of manta ray, Manta birostris, in 2009 in Mozambique.



The tagging is a fundamental part of a comparative worldwide research campaign called ‘Ray of Hope’ funded by the Save Our Seas Foundation (SOSF) and conducted by the Marine Megafauna Foundation (MMF), which is investigating the behaviour and movement patterns of the newly-described giant manta ray. Andrea and colleagues Dr. Simon Pierce and Dr. Juerg Brunnschweiler are travelling to several locations across the globe, teaming up with local researchers or dive operators along the way to locate these mysterious and severely understudied mantas. In Brazil Andrea is collaborating with the Laje Viva Institute and researchers from their ‘Mantas of Brazil’ project.



“This achievement is a piece of manta research history but more than that it is the start of my collaborative work in South America on this species which is currently the only research being conducted on manta rays in the southern Atlantic Ocean. It is a really important step in trying to understand how this species uses the coastline of Brazil, if it travels distances offshore, where their seasonal movements take them and what threats they face on their journeys,” said Andrea.



The tag was deployed last week on a large mature male at Laje de Santos, the largest documented aggregation site for the Manta birostris species in the Southern Atlantic Ocean, and is programmed to stay on the manta ray for 180 days. For the next six months the tag will accompany the manta on its journey through the oceans, functioning like a mini-lab and storing data critical to the investigation. As well as recording the water temperature through which the manta swims and the depths the animal reaches, it also records the light levels and its GPS position every time it breaks the surface, information used in determining the individual’s actual track.



Almost nothing is known about the lives of manta rays in South America and Andrea hopes the study will help answer a series of questions aimed at providing invaluable information for managing the region’s manta ray population and better protecting them from fishing pressure and other human induced threats such as shipping traffic. “As we continue to learn more about these ocean giants, I also continue to learn and grow as a scientist. Patience is an important skill in field research as is the determination to see difficult projects through to completion. In the end, persistence will pay off, and although we sometimes feel that we are racing against time, we are ultimately at the mercy of the animals that we study and the elements of nature. Sometimes sitting back and waiting for them to come to us is the only solution,” said Andrea.



The research is funded through the Save Our Seas Foundation (SOSF).

Tuesday, May 26, 2009

Brian Darvell - Sounding The Alarm

We have come to respect and appreciate Brian Darvells "on the ground" reports of continuing Asian demand for sharks. This week he added a comment to Goblin Girls post that was shocking in it's detail.

Mantas are in trouble. Here's his first person report:

The Chinese slaughter mantas in their thousands for their gill rakers for use in traditional 'medicine'.

The largest Chinese medicine market in China, in Guangzhou - a whole block of shops on three floors of the most amazing things. These included literally tonnes of dried seahorses - shops-full at a time, and similarly manta gills, 10s of thousands that I saw - boxes piled high.

This is NOT a small, subsistence market, by any means. It is a massive, commercial operation that somehow has evaded notice. It can be added to the foul practices of using bear bile, tiger bone, seahorses etc etc for the magical, culturally-sanctioned, devastation of wildlife of all kinds. If it moves - eat it.

It is about time that the centrality of Chinese activity in these matters was addressed properly, instead of pussyfooting around trying not to offend. Culture or long tradition is no longer an acceptable defence for anything, anywhere, now where commercial exploitation is involved. True subsistence use is hard to find, and altogether negligible in impact.