Some thoughts- 
 *mortality is a dablink 
 *"of a "Trygon pastinaca" feeding" Is this a new name without a description? Or is this name a species previously described? 
 *papillae is a dablink 
 *"Repulse Bay" Worth a link? 
 *"not to be the case" Why "to be"? 
 *"the intertidal flats of estuaries and bays, that" If you're specifying which intertidal flats it prefers, lose the comma? Alternatively, if you're describing the nature of intertidal flats generally, change to "which"? 
 *"Known parasites of the estuary stingray include the tapeworms Heterocotyle chin and Shirleyrhynchus aetobatidis,[8][9] the nematode Echinocephalus overstreeti,[10] and the monogeneans Empruthotrema dasyatidis and Neoentobdella cribbi.[11][12]" Links? Don't be scared of redlinks. 
 *"fresh or brackish environments may serve nurseries." Serve as? 
 *"Finally, this ray's reputation for damaging shellfish has led to persecution by commercial shellfish farmers.[1]" Howso? 
 *"This ray is not known to be dangerous to humans.[5]" Feels a bit "tacked on". Also, does it not sting? 
 *:Category:Fish of Australia? 

 Sources, images and stability are good. The lead image isn't ideal, but it seems to be the best available at this time. If you're interested in requesting one, this site may not be a bad place to try.