INTRODUCTION

In November I sent out a message about a bottlenose dolphin (Tursiops
truncatus) with a large wound/lesion on the ventral side of its body.
Photos of the wound can still be found at www.morigenos.org/dolphin_wound.htm

I wish to thank all of you who provided me with your experience and comments.


RESULTS

We received responses from various areas and several people provided
useful comments on the possible cause of the wound.

However, although we do have some ideas about what might have caused
the wound, we were unable to come to any definite conclusion.
Therefore, the true cause is still unknown.

As expected, nobody reported the possibility of the wound being caused
by the animal's conspecifics.

Furthermore, none of the list members, who responded, included the
possibility of a shark bite. In fact, several people said they are
absolutely sure that the wound was not inflicted by a shark.

The following possible causes were suggested by the list members (the
numbers in brackets represent the number of people who suggested that
– the same person could also suggest more than one possible cause).

- Harpoon (2)
- Violent interaction with fishermen (1)
- Injury from (damaged) fishing gear (1)
- Other objects (1)
- Other human launched projectile (1)
- Bacterial infection (septicemic or dermal disease) / zoonosis (2)
- Sea lamprey (1)
- Erupted abscess (1) (this person reported a similar case in their
study area)
- Infection or "pealing" of the skin, resulting from a trauma (2)

Several people reported that the wound has typical appearance of the
healing wound and that it seems to be healing well.

One of the list members noted that similar lesions have been observed
in captivity, resulting from animals constantly rubbing themselves on
pool sides, docks or other objects.


CONCLUSION

Alhtough we were unable to come to any definite conclusion, we got a
useful insight into the possible causes.

It is difficult to either reject or confirm any of the suggestions
with the limited information that we have. All of the suggestions seem
possible, although we believe some of them are more likely than
others.

The photos of the dolphin's ventral side prior to the observed wound
and after the first observation would help us follow the development
and healing of the wound. Therefore, additional and more accurate
conclusions could be drawn from that.

However, the dolphin only performed such aerial behaviours on that
particular day, making it impossible for us to keep track of the
wound-forming or wound-healing process.

Nevertheless, should we acquire additional photos of that body part of
the same animal, the photos could provide us with possible insight
into the healing process, as well as additional documentation, which
could help us determine the cause.


Sincerely Yours,


Tilen Genov


Morigenos – marine mammal research
and conservation society
Jarska cesta 36/a
1000 Ljubljana
Slovenia
www.morigenos.org