Musings of a Citizen Scientist--Time and Tide Wait for No Man or Beluga

This entry is part of a series that describes my participation in the Cook Inlet Beluga Monitoring Citizen Science Project

Sunday September 1, 2019.  Anchorage Small Boat Launch.

The trio of tugs sortie from the float adjacent to the small boat ramp toward the Anchorage wharves as I arrive to begin my two-hour shift scanning the waters of the Cook Inlet for beluga whales.  I surmise the vessels will assist the impending departure of the blue Tote Maritime Lines cargo ship.  Today’s session is one of many over the next three month in the citizen science project to catalog the presence and behavior of beluga under the auspices of the Beluga Whale Alliance and the Alaska Beluga Whale Monitoring Program. The observation period begins in a few minutes at 5:00 p.m. This is my fourth session in eight days at this location and I have yet to spy anyone of the critters.  Harbor seals have been viewed regularly, but thus far no beluga.  Maybe today will be the day! 

Scanning the coastline reveals the physical environment in which today’s monitoring occurs.  Launching anything from the boat ramp would be impossible given the gap between the base of the ramp and water’s edge. The tugs move slowly into the industrial port immediately to the north.  A bit closer, the deep furrow through the grey mud that marks the mouth of Ship Creek lies well above the waterline. The adjacent tidal flats appear littered with fallen tree trunks and root balls—the water-worked remains of once living trees deposited by the eroding shoreline or washed down waterways that enter into the Inlet.  In the next two hours, the incoming tide will fill the boat ramp, inundate the creek channel and cover most of the surrounding tidelands, which when exposed is a mud slurry best described as “part water, part glacial till, punctuated by exposed channels and dead trees.” 

In Cook Inlet, the tide does not so much “rise” as it does “flow” or “flood” On this day, as shown by the graph from the Tides4Fishing website, the second of the two low tides that day was three-quarters of an hour earlier at -4.0 feet.  The next high tide will be at 9:44 p.m. at 33.0 feet, a change of 37 feet in 5 ½ hours--a lot of water movement.  These levels are not quite the maximum low tide for Anchorage of -5.6 feet and a maximum high of 34.4 feet, but pretty close.  The tidal coefficient in red at the top of the chart indicates the likelihood of major currents and fish movements upstream on the incoming tide—two features which factor into beluga behavior.

The  United States Coast Pilot 9 for the vicinity of Anchorage helps put into context what I am seeing:

“Close off the town, the current floods northeast at a velocity of 1.5 knots and ebbs southwest at a velocity of 2.5 knots. One mile off the town, the current averages 2.9 knots. Strong currents that attain velocities of 4 knots or more, at times, in midchannel, and swirls in the area make navigation difficult. It is reported that the flood following the higher of the low waters is unpredictable, especially during the last 3 hours, in the vicinity of the Port of Anchorage wharves.”

The energy of moving this water volume is evident as the dead trees lift with the rising tide and entrain in the tidal rips moving quickly past out observation point.  Each draws our attention, as any out of the ordinary movement on the water is likely to do when scanning for beluga.  Binoculars on the target confirm it is a submerged log; one of many we see that day.  It seems a collision between a boat and the log would leave the boat much worse off from the encounter.  In some cases, when the log may float near vertical, it would appear that the cryptid Loch Ness monster resides in the Inlet as well as the beluga.

These conditions are conducive to observing beluga.  According to NOAA’s 2016 Cook Inlet Beluga Recovery plan “habitat use in the summer months consists of semi-predictable movements of groups of belugas between river mouths and shallow tidal flats in the upper Inlet. These movements are largely cued to physical conditions, especially tide…. Traditional ecological knowledge indicates that daily movements are determined by the ebb and flow of the tide and the related movements and size of fish runs,...”

Soon, we spot three beluga—an adult, juvenile, and calf travelling to the north past the port.  It would seem that ingredients for a sighting were present, just add beluga and the observers to record their transit.  Shortly after the belugas pass, the tugs escort the cargo vessel out of the port and into Knik Arm where it heads southbound for its next destination.  These movements as well as other factors are duly recorded.