Giant Freshwater stingray research in Thailand

July 2009. Giant Freshwater Stingray research in Thailand is progressing well with the Fishsiam Ltd team now having accounted for the capture of 96 individual Giant Freshwater stingrays. All fish caught are now examined by the Chulalongkorn University Research team in Bangkok under the supervision of Dr Nantaika Chansue who is the world's leading veterinary authority on the species.

The expert veterinary science team under the direction Dr Chansue has been engaged in groundbreaking research of Giant Freshwater Stingray and has been working alongside National Geographic explorer Dr Zeb Hogan on various scientific studies concerning the species.

Research - Acoustic and numerical tags
Dr Hogan and the research team have successfully surgically implanted acoustic tags in numerous Giant freshwater stingray and deployed receivers at strategic locations along the Maeklong River which are now being used to monitor the fish's movements. Additionally numeric external tags have been placed on fish to assist in identification in the event of any recaptures.

Measurements
The scientists have been collecting all relevant data from captures made by the Fishsiam team with all fish being measured accurately recording widths and lengths for future assessment of Giant Freshwater stingray growth rates.

Venom similar to pit viper
Other groundbreaking studies carried out by the scientists have included the collection of the poisonous mucus from the barb of the Giant freshwater Stingray for use in toxicology testing. Initial toxicology tests have shown the venom to share characteristics with that of a Pit Viper with the poison inflicting a fast acting necrosis and extreme pain to victims.

The Chulalongkorn University research team has been working alongside members of the Red Cross in an effort to produce a vaccine to combat the effects of the toxins/mucus found on the barb of Giant freshwater stingrays.

This Giant Freshwater stingray was possibly the larest freshwater fish ever caught. The enormous leviathan with a width of over 2 metres was safely secured before being brought back to the waiting scientists at the riverside. The fish was observed to be heavily pregnant and it was decided not to attempt to weigh the Monster fish. Courtesy of Fishsiam

DNA & blood samples
The scientists have also been collecting DNA & blood samples from all fish caught for genetic comparison with specimens that the team has caught from the Ban Pakong River in Chachoengsao in addition to fish caught from other rivers and in aquariums throughout Thailand. 

Captive fish in poor health
Comparison of blood samples taken from fish held in captivity with wild Giant freshwater stingray caught by the Fishsiam team has revealed a vast difference with a massive difference in health levels. Wild fish even directly after capture have displayed much greater levels of vitality and health when compared to stingrays held in captive environments & aquaria.

Pregnant females
Blood samples obtained by the scientists from pregnant females have shown an ability to clot almost instantly on extraction. It has been suggested that this clotting ability may be a natural defensive mechanism designed to make sure stingrays do not attract predators at birthing times with large amounts of diluted blood.

The collection of parasites found internally on the gill covers of Giant freshwater stingray has also been conducted for further scientific research and comparison with other specimens caught by the team in addition to other species of stingrays such as the Amazonian Giant Freshwater stingray.

Pregnant females
Recent expeditions to the Maeklong River in Samut Songkran Province have seen several large females captured which have been found to be pregnant indicating a healthy and breeding population is present in this particular river system.

Two separate occasions last month saw large female Giant Freshwater stingray being observed to give birth to live newborns whilst being examined at the riverside. On the 23/05/09 a large female Giant freshwater stingray gave birth to twin newborns with male and female specimens of 42cm's in width being recorded. A closer inspection with Ultrasound equipment found the large female to have at least two other newborns waiting to be born. Due to the condition of the fish the large Stingray and its infants were released promptly after scientific data and measurements were recorded.

The Fishsiam Team was recently joined by Stefan Lovgren and Dr.Zeb Hogan from the National Geographic news team. Whilst filming at the Ban Pakong River the team caught a large female Giant Freshwater Stingray which was observed to be heavily pregnant. While being held at the rivers edge the prehistoric predatory giant gave birth to a live newborn measuring a mere 34cm. This ground breaking capture is the first documented example of a Giant Freshwater stingray birth in its wild and natural enviroment and a good sign for this highly understudied and obscure species. The mother and infant were safely released together after Dr.Zeb Hogan recorded measurements and made a short scientific examination. Courtesy of Fishsiam

Another capture on the 27/05/09 saw the capture of a very big Giant freshwater stingray of well in the excess of 200kg's (2.1m). On this occasion the large female gave birth to a live newborn stingray with a width of 36cm's which was identified to be a small male. The fish on this occasion was clearly holding more babies and was quickly released after basic dimensions and scientific data were recorded for further scientific investigation.

Giant Freshwater Stingray Research expeditions

Fishsiam Ltd Thailand is proud to announce an exciting series of research expeditions for the coming year in search of Giant freshwater stingray in association with emerging National Geographic explorer Dr.Zeb Hogan and expert veterinary scientists from Chulalongkorn University in Bangkok. Conservation minded anglers will be given the unique opportunity to fish alongside Dr.Zeb Hogan during field trips to various locations in search of Giant freshwater stingray.

Megafishes project Director Dr.Zeb Hogan will be working alongside Associate Professor Dr.Nantaika Chansue with her expert team of aquatic veterinary scientists from Chulalongkorn University in Bangkok in an attempt to mount the world's first comprehensive study of the awesome Himantura Chaophraya/Giant freshwater stingray.

The forthcoming research expeditions, which have official approval from the Department of Fisheries in Thailand, will see conservation minded anglers fishing at various locations throughout Thailand in search of the Giant freshwater stingray.

Anglers will be pushed to their absolute physical limits in pursuit of what has been described as possibly the largest freshwater fish in the world whilst also contributing to the ongoing research of this highly enigmatic prehistoric predatory fish species.

$100 donation towards Megafish conservation
Conservation minded anglers attending these trips will be assisting in the funding of Giant freshwater stingray research with a $100 USD donation being contributed towards the continued conservation and research of Megafish in Thailand from each expedition.