No less than 215 anglers from throughout the UK participated in the 2009 Scottish Sharkatag organised by the Scottish Sea Angling Conservation Network (SSACN).

The Sharkatag had three goals:

– To highlight the perilous state of the endangered shark species.

– To gather data to support claims for their protection.

– To press politicians and fisheries managers to recognize the needs of the sea angling community and its contribution to the Scottish economy.

The information gathered during the Sharkatag will feed into SSACN’s Scottish Shark

Tagging Programme; a program dedicated to broaden our knowledge of shark, skate and ray stocks in Scottish coastal waters.

Attending anglers caught, tagged and released various shark species from boats, kayaks and the shoreline of Solway in South West Scotland, and what they found was worse than expected.

“It really worries me that many of the tope packs have failed to

show this year“, says Ian Burrett, SSACN’s Project Director. “The whole region seems to be void of the expected male breeding stock and the fish caught were mostly immature females, typically under twenty pounds and a few solitary females in the 50-60 pound range; Luce Bay was especially poor for the time of year.”

The Tope shark (Galeorinus galeus), also known as the School shark, Soupfin shark and Snapper shark, is a type of hound shark found at depths down to 550 metres (1800 feet). It can reach a length of 2 metres (6.5 feet) and is listed as Vulnerable at the IUCN Red List of Threatened Species.

The situation was equally worrisome for several other species of shark and ray.

“Around two hundred tope, smoothhound and bull huss were tagged over the three days and that can only be described as poor compared to what the total should have been, says Burrett. “Combined with the lack of rays tagged, only three throughout Sharkatag, it shows how urgently plans are needed to helpprotect and regenerate the stocks. Twenty year ago virtuallyevery boat would have recorded several mature tope and rays.”

You can find more information at the Scottish Sea Angling Conservation Network’s website www.ssacn.org and the website of SSACN’s Scottish Shark Tagging Programme www.tagsharks.com.

If you want to learn more about how the charismatic creatures known as stingrays feed, you should check out a new study published in the most recent issue of Neotropical Ichthyology.

While spending days and nights scuba diving and snorkelling in the upper Paraná River of Brazil, researchers Domingos Garrone-Neto and Ivan Sazima made 132 observations of freshwater stingrays and noticed three different forms of foraging behaviour.

Picture of Motoro Sting Ray, Ocellate river stingray – Potamotrygon motoro.
Copyright www.jjphoto.dk

The first hunting technique involved hovering close to the bottom, or even settle on top of it, while undulating the disc margins. By doing so, the stingray would stir up the substrate, unveiling small invertebrates. The invertebrates – typically snails, crabs and larval insects – could not escape from under the ray’s disc and ended up as food.

When using its second hunting technique, the stingray would slowly approach shallow water while keeping its eyes on suitable prey items that concentrate in such environments. When it got close enough, it would make a rapid attack; stunning the prey or trapping it under its disc. This hunting technique did not target tiny invertebrates hiding in the sand; it focused on tetras and freshwater shrimps instead. The studied stingrays only used this method during the night when they could sneak up on prey without being seen.

The third technique observed relied on the presence of vertical or inclined surfaces in the water, such as boulders and tree stumps, including man-made structures like concrete slabs. On this type of objects a lot of different organisms, e.g. snails, like to crawl around or attach themselves. The hunter would simply position itself with the anterior part of its disc above the water’s edge and start picking the animals off the surface, one at a time.

The two studied species were Potamotrygon falkneri and Potamotrygon motoro; both belonging to a genus of freshwater stingrays found exclusively in South America.

As mentioned above, you can find the paper in Neotropical Ichthyology 7.

Garrone-Neto, D and I Sazima (2009) Stirring, charging, and picking:

hunting tactics of potamotrygonid rays in the upper Paraná River. Neotropical Ichthyology 7, pp. 113–116.

According to Wildlife Extra, 12 different specimens of the endangered Giant freshwater stingray were caught in over the course of just 3-4 months last year. The findings where made in both the Ban Pakong and the Maeklong Rivers, and one of the specimens was a young stingray measuring no more than 12 cm (4.7 inches). This might be a sign that the Giant freshwater stringray is somehow managing to combat the dangerous pollutions that are contaminating its habitat.

The specimen that received most attention was of course the enormous stingray caught by Tom Parker from Coventry whilst on a guided fishing tour to the Ban Pakong River. After being measured and photographed, the rare fish was fortunately released back into the wild. The Giant freshwater stingray had a wingspan of 2.4 meters (7.9 feet) and weighing it turned out to be impossible for the fishing party.

A research project has now been launched by Dr Terry Bertozi of the Evolutionary Biology Unit of the South Australian Museum in Adelaide, Australia and the fishing company FishSiam in order to find out more about the elusive Giant freshwater stingray.

You can learn more reading the full article at Wildlife Extra: http://www.wildlifeextra.com/giant-stingray930.html

Stingrays have flat bodies that make it possible for them to stay hidden in under layers of sand at the bottom until an unsuspecting animal ventures close enough to become lunch. Some stingrays grow really huge, as the one in the article, but others can be kept in normal hobby aquariums. It is very important to provide them with a suitable substrate in the aquarium to allow them to carry out their natural habits. You can learn more about a few species of stingray that can be kept in aquariums here: http://www.aquaticcommunity.com/predatory/sting.php