Monday, September 29, 2008

Porpoise Paddling

Kachemak Kayaking

The southern shore of Kachemak Bay is lined with numerous fiords and lagoons which are subject to huge changes in water level as the tide ebbs and flows. This surge of moving water can create tidal rips and eddies around points and in narrows which can threaten small boats but also can create some very exciting conditions for kayakers.

One of the largest tidal variations in the Bay is dramatically apparent at Halibut Cove Lagoon. The narrow channel shown here during a negative low tide will flood over the entire gravel bar on the left to a depth of as much as 30 feet in just 6 hours. The sea water moves slowly at first but gradually builds to an 8 knot current as water barges its way into the lagoon. The fast moving water interacts with the steep cliff on the right creating several large eddies behind the jutting points. As the channel widens boats can avoid the hazards by staying away from the edge but for kayakers those same hazardous eddies can provide some excitement.

During a trip into the lagoon to "ride the tide" last year we also found that bay porpoises seem to use the tidal surge by swimming into the current and feeding on the various fish which are washed into the lagoon. Our group leader, Tom Pogson, owner of Alaska Kayak School, was filming us having some fun in an eddy when two of those porpoises swam by....

video

Charlie Franz, the former director of the hospital in Homer does the first "peel out" from the eddy into the main current, then myself and finally Ryan, a kayak guide from Seward, actually rolls with the porpoise. If you didn't know where this video was taken you might think that it is shot on a fast flowing river, not an ocean lagoon. In many ways the Lagoon Narrows acts just like a river- except it reverses direction every six hours and changes its depth as much as 30 feet.

1 comment:

Nan said...

That roll surprised me I didn't think he was going to do that !!