Hi Sammy... Great report, as always.

Looks like the Tri Tri might be Elvers (young eels that spend time in fresh water before heading to the oceans).
Big thing in my local river, The Severn, in England. Here's a link that I hope will work ( not all BBC links are available outside of the UK) http://news.bbc.co.uk/local/gloucestershire/hi/people_and_places/nature/newsid_8864000/8864173.stm

p.s. Are you doing any of the WARC?