[MARMAM] about the trapped river dolphins
Enzo Aliaga Rossel
ealiagar at hotmail.com
Thu Sep 2 07:43:39 PDT 2010
I asked some advise about river dolphins that were trapped in a segment of a river in Bolivia. The rescue of the trapped dolphins locally called bufeos went very well, it was a challenging experience were we learned a lot from the whole process.
Finally we move them by road (very dusty and rough, but we did not have more options) it took from 15 to 20 min to the area was blocked and then by boat (by the river Rio Grande)
>From the original 9 (max 12) that we initially counted, finally we rescued 20 bufeos!!!. The dolphins were trapped in an area of 1 km by 18m wide; it seems difficult to think such error on the counts. So I think it would be interesting to discuss the methods of evaluation.. we used the modified strip transect (counting around 8 times, while we were monitoring the general status of the area, or looking for possible mortality). If there is the possibility that generally we are underestimating river dolphin populations?.
Because of the logistic we release them in 3 areas of the same river (rio Grande) 9 individuals 20 km from the blocked area; 7 individuals 10 km (after some rapids), and 4 individuals were released in the blocked area (were the Pailas river used to flow to the Rio Grande).. During this season (dry season) these 3 areas are divided by rapids or shallow waters, but during rising and high season the water level wont be a obstacle for the dolphins to reunite.
There were several females, 2 of them pregnant, 2 of them have newborns (both were released close to their mothers) and we saw them days later swimming together. One male dolphins surprised us because he did not have the left pectoral fin.. probably this happened long time ago,this area was completely healed (it seems that it was cut by a net), I dont know this is an frequent situation. None of them showed signs of physical damage from the rescue, of course they showed some signs of stress and some scratches from the capture but we think they are fine.
Thank you for all your advise, comments, suggestions and interest.
Enzo Aliaga-RosselPhD CandidateUniversity of HawaiiEECB Program
Associate ResearcherInstituto de Ecologia- UMSALa Paz-Bolivia
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