Smalleye stingrays are the largest marine stingrays on record, reaching disc widths of up to 222 cm, and yet almost nothing is known about them. Scientists from the Marine Megafauna Foundation have for the first time used photo IDs to study this elusive animal in southern Mozambique, one of the only locations where it is regularly seen in the wild. Their findings were published in the journal PeerJ.
“We reported the first sightings of smalleye stingray in 2004 and have since been racing against the clock to learn more about their ecology before it is too late”, said Dr Andrea Marshall, co-founder and principal scientist of the Marine Megafauna Foundation. 31 percent of the world’s sharks and rays are threatened with extinction according to the IUCN Red List of Threatened Species ‒ due to lack of scientific effort and information, it has not been possible to evaluable the conservation status of smalleye stingrays to date. “This species of ray is likely in trouble too but we can’t protect what we don’t know much about. Our study is an important first step in understanding more about the animal’s ecology and behaviour“, she added.
“These mysterious giants are thought to be patchily distributed across the Indian Ocean and Western Pacific, but southern Mozambique is probably the best location to encounter them on inshore reefs”, Marshall added.
The marine biologists tested whether photographs of the stingrays’ (Megatrygon microps) white dorsal spots could be used to distinguish and track individuals over long periods.
“Through local dive centers, we called on tourists to help us collect images of this solitary stingray. Fortunately for us, southern Mozambique and its rich marine life attract many passionate scuba divers, most of which own GoPros or other lightweight cameras and will happily make their images and footage available for research”, said Atlantine Boggio-Pasqua who volunteered with the Tofo-based foundation.
She added: “Their contributions proved immensely valuable, we managed to gather more than 140 photographs suitable for comparison and identification, with some images dating as far back as 2003.”
The team was able to visually identify 70 different individuals, including 15 that had been seen on several occasions in the area. The dorsal spot patterns looked unchanged over the years indicating they may be permanent markings like in manta rays.
Boggio-Pasqua said: “Smalleye stingrays may look intimidating at first glance with their large, razor-sharp tail spines, but they’re actually really charismatic and easy to approach. We hope to receive many photo and video contributions from citizen scientists in future. They could tell us more about the species’ habitat preference as well as feeding and cleaning behavior.”
The encountered stingrays were often spotted at cleaning stations where reef bannerfish and other small fish appeared to be removing parasites from the rays’ skin.
The photographic study also provided a glimpse into the migratory behaviour of Megatrygon microps. Some individuals traveled hundreds of kilometers along the coastline, including a near-term pregnant female which traveled from Tofo to the Bazaruto Archipelago and back (200km in a minimum of 102 days and a total 400km return trip). She returned to Tofo, no longer visibly pregnant, suggesting this individual had pupped during her journey.
This proved to be the longest straight-line distance ever recorded for any species of whiptail stingrays (Dasyatidae family). Unlike other stingrays, smalleye stingrays are rarely seen resting on the seabed and are thought to be semi-pelagic.
Smalleye stingrays are likely under threat from increasing fishing pressures. Targeted and incidental catch in coastal gillnets and industrial purse seiners operating offshore are an ongoing issue in Mozambique.
“There are so many questions that remain unanswered about this rare species. Where do they live, how fast do they mature and how do they reproduce? Filling these knowledge gaps is crucial to figuring out how to protect them properly in Mozambique and other parts of the Indian Ocean”, concluded Dr Marshall.
Addressing the lack of available data will eventually allow scientists to formally assess the species’ conservation status in the IUCN Red List and inform management practices.
The study by Atlantine Boggio-Pasqua, Anna Flam and Andrea Marshall, titled ‘Spotting the “small eyes”: using photo-ID methodology to study a wild population of smalleye stingrays (Megatrygon microps) in southern Mozambique’ is published in the journal PeerJ on 11 June 2019 and is freely available here.
For more information about the work of the Marine Megafauna Foundation visit their website by clicking here.
WIN a Beuchat Air Light Bag!!!
For this week’s competition, we’ve teamed up with our good friends at Beuchat to give away an Air Light Bag!
The Air Light Bag from Beuchat is a practical travel bag that takes up minimum storage space.
- Material: 600 denier and 1,000 denier nylon/PVC
- Soft roller bag, easily stored in its mesh bag
- Internal retaining straps
- Zip fastener with eyelets for padlocks
- Side compartment for fins
- Outer document pocket with coated zip and carry strap
- Backpack style straps concealed behind the foam back-plate
- Drainage vents
- Red over-moulded wheels; detachable wheel block
To be in with a chance of winning this awesome prize, all you have to do is answer the following question:
In a recent post on Scubaverse.com (which you can read here), we reported that the Philippines have been recognised as the World’s Leading Dive Destination at the 27th World Travel Awards. In the article it states how many islands make up the Philippines… how many are there?
- A) 7,209
- B) 7,532
- C) 7,641
Answer, A, B or C to the question above:
Quick Scuba Tips #1: How To Prep A New Mask for Scuba Diving (Watch Video)
How To Prep A New Mask for Scuba Diving. Can’t I just take my new mask diving straight out of the box? Well, actually, no. It needs a little work to make it dive ready.
In this, the first in our new scuba diving quick hints and tips series, I’m going to show you how to prepare a new mask for scuba diving with three quick techniques, all aimed at stopping your scuba mask from fogging.
- Here’s a link to that Cressi Mask: https://amzn.to/39EEol5
- Here’s a link to Stream2Sea: https://stream2sea.com/?ref=o-51ln3gn2c
Yes, this link is an affiliate link. Purchases made through these links may earn me a small commission at no extra charge to you.
Dive safe, dive often!
Subscribe here: http://bit.ly/DiversReady
WIN a Beuchat Air Light Bag!!!
For this week’s competition, we’ve teamed up with our good friends at Beuchat to give away an Air Light Bag!...
WIN a Bigblue AL-1200NP Dive Torch!!!
For this week’s competition, we’ve teamed up with our good friends at Liquid Sports to give away a Bigblue AL-1200NP Dive...
WIN a Tovatec T3500S Rechargeable Dive Light!!!
For this week’s competition, we’ve teamed up with our good friends at CPS Partnership to give away a Tovatec T3500S Rechargeable Dive Light...
WIN a Fourth Element Arctic Hoodie!!!
For this week’s competition, we’ve teamed up with our good friends at fourth element to give away one of their NEW Arctic...
Sharks Bay Umbi Diving Village is a Bedouin-owned resort with stunning views and a lovely private beach. It is ideal for divers as everything is onsite including the resort's jetty, dive centre and house reef. The warm hospitality makes for a diving holiday like no other. There is an excellent seafood restaurent and beach bar onsite, and with the enormous diversity of the Sharm El Sheikh dive sites and the surrounding areas of the South Sinai, there really is something for every level of diver to enjoy.More Less
- Competitions1 month ago
WIN one of the NEW Momentum M20 Dive Watches!!!
- Competitions4 weeks ago
WIN a Northern Diver NDB5 Holdall Bag!!!
- News2 months ago
SeaLife launches new underwater housing for iPhone
- Gear News1 month ago
Breaking News: Garmin Descent Mk2 & Mk2i Launch & Review (Watch Video)
- Competitions3 months ago
Another chance to WIN a Sharkskin 90L Performance Bag!!!
- Marine Life & Conservation2 months ago
Review: My Octopus Teacher
- Competitions3 months ago
WIN a Sea Dragon Mini 900 Dive Light from SeaLife!!!
- News2 months ago
Escape to Zanzibar this Autumn