Northwest Fisheries Science Center

Newportal Blog

A gateway to oceanographic adventures from the Newport Line and beyond

Blog on ocean conditions along the Newport Line and the northern CA Current.

Flock this way! Marine birds and mammals point out productive habitat

By Jen Zamon
July 16, 2015

During the juvenile salmon survey, we are not only interested in the numbers and condition of juvenile salmon, we are also interested in other organisms such as marine birds and mammals that interact with, and might prey upon, juvenile salmon.  Because most marine birds and mammals depend upon small fish, krill, or squid for their primary food supply, knowing where these animals are gives us a window into where the productive areas of the ocean are.  To better understand this, each morning we count marine birds and mammals on our survey lines.

The work begins at dawn.  One person counts while a second person records counts into a computer program that adds a time, date, and exact location with each observation.  In our study area, it is normal for only two species to make up over 80% of the birds we see nearshore in summer.  These two species are the sooty shearwater, an albatross relative which migrates here all the way from Chile and New Zealand; and the common murre, a puffin relative which nests on the bare rock of cliffs and sea stacks in northern temperate seas.  It can be very exciting when you come into groups of thousands of hunting birds churning up the water in a feeding flock - it literally looks like a tornado of activity.

What was a bit unusual during the June 2015 survey were the apparently large numbers of pink-footed shearwater (a member of the albatross family that also migrates here all the way from Chile, where there are only three known breeding colonies), Cassin’s auklets (a small member of the puffin family), and humpback whales.


The diet of pink-footed shearwaters is a bit of a mystery, but they probably eat squid and small fish.  While, Cassin’s auklets depend exclusively on krill and other large plankton, and humpbacks consume both krill and small fish.

We encountered dozens of humpbacks during our survey, most putting on quite a show all day long – slapping their tails and large front flippers, and jumping out of the water in spectacular, ship-soaking, full-body breaches.  We also were graced with visits from many smaller whales like Pacific white-sided dolphins, who were apparently trying to outdo the humpback show; and Dall’s porpoises, who came over one evening to surf on the bow-wake created by the FV Frosti.

Pacific white-sided dolphins (Lagenorhynchus obliquidens): Here is a Movie showing off their bow-riding prowess on a calm evening at sea. Many dolphins and porpoises ride the pressure waves created by boats moving forward in the water. It is thought that marine mammals bow-ride for the same reason human surfers surf – it’s a heck of a lot of fun, and a way to show off for your buddies!

Dall’s porpoises (Phoecenoides dalli): Movie of them catching a ride on the bow of the Frosti. These porpoises have a striking, hourglass-shaped black-and-white pattern on their bodies, and are thought to be the fastest-swimming of all the small whales – up to 55 km per hour. Bow-riding is a form of play that hones key swimming skills: you have to be fast, maneuverable, and work as a team to successfully catch enough fish to make a living.

Tagged: Salmon Survey, Marine Birds and Mammals

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