May 03, 2011

Stingrays in the neighborhood

Estuary Stingray
Aside from the birds of the air, Beachmere is also home to many stingrays who approach the shoreline on each incoming tide.

Wading the shallows will more often than not disturb one of them and in a swirl of silt and sand, they'll rise from the bottom and fly away flapping their wings as if they were underwater birds.

You can come upon them in as little as 30 cm of water.

If the water isn't clear --- a common event in Deception Bay-- all you'll see is the swell as the stingray rises and the shock wave causes a surface swirl.

Wading, you need to always think about what may be at your feet.

When wading the shallows you can do "The Texas Shuffle" . In other words, slide your feet as you walk to alert stingrays of your presence. Instead of stepping on a stingray, you will at worst only nudge them and they will swim off (usually).

This time of year with the clear Autumn water it is thrilling to wade the shallows and come upon rays and skates  at close quarters. Rather than only seeing the dark shapes and water surges, you can watch them rise from the bottom and swim away -- sometimes in pairs -- directly out to sea.

During a wade or a paddle the number of stingrays you may come upon in each section of beach can seem quite impressive. Wading in the shallows I've counted up to 15 within 300 metres along the shoreline, but it is clear that as the tide recedes the number of 'stingray holes' left behind by the feeding rays  suggests that large numbers may come in with each rising tide. And the size of  some of the holes -- which are an imprint of the rays that created them -- suggest that many of the visitors are large creatures. 

Stingray Holes, Beachmere
After a few observations it seems to me that the most common species along the shoreline may be the Estuary Stingray 
The estuary stingray, estuary stingaree, or brown stingray (Dasyatis fluviorum) is a species of stingray in the family Dasyatidae. It is found along the coasts of Queensland and New South Wales in Australia, and typically inhabits rivers and estuaries in mangroves. Growing to 93 cm (37 in) across*, this yellow-brown to olive stingray has a rhomboid pectoral fin disc and a smooth, whip-like tail with both dorsal and ventral folds. Its long, narrow nostrils and row of thorns along the midline of the back are additional characteristic features.
Crustaceans and polychaete worms are the main food of the estuary stingray, though it has a perhaps undeserved reputation for consuming farmed shellfish such as oysters. This species has declined or disappeared in many parts of its historic range, likely from a combination of habitat destruction, commercial and recreational fishery activity, and persecution by shellfish farmers. As a result, the International Union for Conservation of Nature (IUCN) has assessed it as Vulnerable....
While other species approach the shoreline each day,  I suspect that the Estuary Ray is among the most common of visitors -- intent on a daily feed of soldier crabs.

 Of the species the Qld Dept of Environment writes:
Estuary stingrays were once common in south-east Queensland. However, the rapid urban growth along the Gold Coast, Moreton Bay and Sunshine Coast coastline has placed enormous pressure on their habitat. Historically, the estuary stingray was present on the east coast from Port Jackson, New South Wales, to the tropics, but it has not been reported along the central NSW coast since the 1880s. Its southernmost limit is now thought to lie around Forster, NSW.... there has been a considerable contraction of its range and a decline in abundance. Numerous human induced threats have been contributing factors in this decline. Development and construction of industries, marinas and urban settlements in coastal areas has been accompanied by substantial losses of estuarine wetlands. The species appears particularly vulnerable to such human activities due to its reliance on shallow tidal and mangrove habitats, particularly within estuaries and rivers.
Bycatch in commercial fisheries, persecution by shellfish farmers and destruction of incidental catches by recreational fishers and during some commercial fishing activities have also contributed to this decline. It has been shown that a high proportion of rays in some areas of Moreton Bay bear hook wounds and fishing-related injuries.
However, in the next digital breath these magnificent creatures are still a marine enigma.
Even the answers to basic questions about the estuary stingray, such as their age at maturity and lifespan, are unknown.
It is recommended than when fishing you avoid using stainless steel hooks " If these are left in the animal after capture they can last for years as they do not rust. They continually wear leaving the wound raw and open for infection that can eventually kill."

Of course the stingray isn't without its defences so it it warrants reviewing the following first aid and wound management:


  • Immersion of the affected part in hot water (about 45C) for at least 30 minutes for pain relief (relief is generally only effective while the affected part remains immersed).
  • X-ray of the affected body part to exclude the presence of cartilaginous barb remnants.
  • Local infiltration of local anaesthetic.
  • Systemic analgesia.
  • Careful wound examination, removal of foreign material, irrigation and debridement.
  • Heal by secondary intention (not closing the wound and allow to close from bottom up).
  • Antibiotic cover, broad spectrum.
  • Tetanus booster if required.
  • Early referral of confirmed or suspected penetrating injuries of chest or abdomen.
* Other sources suggest that the Estuary Stingray may measure up to 120cm across the body.

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