Posted on Tuesday, 8 May 2012
At 10h45 we located roughly 500 common dolphin 1NM NW of Seal Island heading in a NW direction. Earlier en route to Seal Island we located a small splinter group of roughly 15 common dolphin 5 NM W of SI. These dolphins were not at all interested in interacting with our vessel and may have been separated from the main school earlier in the day by a previous hunt.
The main school of dolphins approached us and when within 300m we saw the fins of at least two orcas 300-400m astern of the school. We then saw that there were 4 orca’s and these four were A group that we had seen 2 days previously. The orcas then followed the school for roughly1 hr herding them in a circular pattern with the diameter of the circuits being roughly 1km. The orca’s appeared to be very relaxed and seldom put on any fast bursts of speed except for two occasions, the second of which resulted in a full spectacular aerial breach. The result was that the dolphins broke their circular orbits and fled at high speed in a ENE direction. The orca’s did not pursue them. It would appear that due to the relaxed pursuit for the previous hour that the orca’s may well have fed earlier resulting in the split group of dolphins we saw en route to the island. Of interest was that both attempts on the school of dolphin were into the sun in an Easterly direction.
In both cases it is suspected that the hunting and breaching orca was Cleopatra.
The orca’s appeared to be very relaxed and seldom put on any fast bursts of speed except for two occasions, the second of which resulted in a full spectacular aerial breach.
Upon termination of the hunt the dolphins fled in an ENE direction whilst the orca’s moved SSW at a speed of 5-6 knots. Once again Mannemerak approached our vessel and rode at the stern of the boat for over 2 minutes and 1 minute respectively at one stage inverting completely whilst watching myself, Monique and guests hanging overboard. Mannermerak was briefly joined by one of the two smaller pod members who also rode on our stern for 10-15 seconds. At the same time Cleopatra and the remaining orca swam within a few dozen yards of each other half a mile ahead. Dave Hurwitz who was with Cleopatra said he saw a very large dorsal fin of a male ahead of his vessel that he saw surface 4 times. We never got to see this male unfortunately but it could be the same male that was seen off Cape Point on the same day as we saw this group on our second sighting of them in 2009. It appears that this male is a lot shyer than the rest of the pod members. We left Mannemerak and the pod when 3 nm SW of Seal Island for a total sighting time of 2 hrs.
Once again this was an incredible interaction to watch. What has also been interesting to note is three different hunting strategies observed to date. The most common seems to be a follow of the school of dolphin for a period of a few minutes and then a rapid rush resulting in a breach into the group. If a dolphin is separated without incapacitating it then there appears to be a pursuit, lasting up to 3nm as seen two days earlier. On previous hunts the attack on the school was relatively rapid but on this occasion the pod appeared to coral the dolphins for a long time and followed them for over 45 minutes as in today’s case, perhaps waiting for the dolphins to panic and pick off a young or confused animal. This method may be more likely when the orca’s have already fed earlier and are less motivated to use large amounts of energy to catch their prey.