July: a long way between bites

This summer (2010) in Johnstone Strait seems “normal” in some ways, but there have been worrying aspects to what is happening too.  The first arrivals came pretty much when we expected them, early in July (3rd).  As usual, they were an “A” clan matriline, this time the A36 brothers, Plumper (A37) and Kaikash (A46).  They were accompanied by the matriarch A12 (Scimitar).  The three orcas spent 2 days in western Johnstone Strait and Blackfish Sound, and then headed east.  Their destination was Nodales Channel, 80km distant, and a roughly 12 hour swim at a relaxed pace.  This is a popular fishing spot for sportsfishers, and this July they were catching lots of Chinook (Spring) salmon, the orcas’ favourite food.  The 3 orcas remained in and around the Nodales area for 4 days, foraging energetically with great focus, and having a good time doing so, despite all the boat traffic around them.

After their Nodales feast, the orcas made their way back to Robson Bight, and thence to western Johnstone Strait, where they spent less than a day before heading back east to Nodales Channel again.  On July 7th, a second arriving group, consisting of the A8s (Holly’s family) and the A11s (Yakat’s family) with Springer (A73), came into Johnstone Strait.  After a bout of foraging in Robson Bight, and a first-of-the-season rub, they too headed east, and by next morning had traveled through Nodales Channel and into Frederick Arm, another good Chinook fishing spot.  Possibly not content with what they found, or perhaps having figured enough of the situation out, they soon turned around, and less than a day later were back in Robson Bight. Over the next 3 weeks, the two groups made 7 more round trips from Robson Bight and western Johnstone Strait to Nodales Channel and the adjacent waterways, often pausing for less than a day (sometimes for just a few hours) before making the return trip.

As orca travel distances go, 80 or 100km isn’t all that far, but it is still quite a long way, and doing it so repetitively must have required a significant output of energy from Yakat & Holly’s families.  As perspective, in a truly “normal” year, the orcas might travel from “Turn Point” at the western end of Hanson Island, to the eastern boundary of the Ecological Reserve at Robson Bight, 15km away, and then back again, quite possibly repeating the circuit before day’s end.  They would have spent time foraging in Robson Bight and elsewhere along the way, engaged in relaxed socialising between bites to eat, and traveled perhaps less than half as far as they were doing during July this year.

For “resident” orcas, body energy comes from fish, and Chinook salmon are their food staple.  It seems reasonable that the orcas would go out of their way to find their favourite food; but it is worrying that so much of their energy in July was being spent moving from one good fishing spot to another.

The scenario speaks to the orcas’ shrinking world.

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