The Daily Bucket is a nature refuge.
We amicably discuss animals, weather, climate, soil, plants, waters and note life’s patterns.
We invite you to note what you are seeing around you in your own part of the world, and to share your observations in the comments below.
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September 26, 2019
Salish Sea, PacificNorthwest
A few days ago we took the boat up the island to the marina for its annual maintenance, which requires taking it out of the water. It was very low tide when we got there so we had to wait an hour or so until there was enough depth at the pull-out spot by the shore. I spent that time wandering around the dock watching aquatic activity.
The tide was coming in fast, there being a big difference between high and low tide that day, at new moon. Even inside this very protected bay the water flows fast under the floating dock. Critters both attached to the side and those under their own steam were very busy scooping up bits of food drifting in with the tidal current.
The most obvious foragers were some kind of surfperch, most likely Shiner Perch (Cymatogaster aggregata), who snag copepods and other plankton as they are carried into the bay. Shiner perch are well adapted to waters with variable salinity. This bay has several small runoff streams bringing fresh water into the bay, varying seasonally with precipitation so the water can get pretty brackish at times.
Invertebrates and algae attach themselves to the sides of the dock. Because the dock floats, going up and down with the tide, they are constantly immersed, a much better living situation than the intertidal zone where nutrient filled water is only available at high tide. I was standing up so I couldn’t get a look at the smaller critters but there are many. I’ve seen various kinds of nudibranchs, snails, brittle stars, crabs, urchins crawling amongst the seaweeds and attached critters like assorted barnacles, tubeworms, anemones.
The larger inverts include the white Metridium sea anemones. Aside from docksides like this the only place to see Metridium is in deeper water, below 30’ so I enjoy watching them here, even these smaller individuals. In deeper waters they can get as big as a person.
The orange stuff is a colonial tunicate, a filter feeder. These animals have a a texture like hard boiled egg, as compared to the spongey feel of sponges — all you have to do is touch them to know the difference, since they are both colorful filter feeders without much shape. There are many kinds of tunicates, the solitary kind looking like little vases of one shape or another. The feathery brown stuff is a mass of colonial hydroids, also filter feeder. Hydroids use stinging cells like anemones and jellyfish, all in the same group of animals.
The anemones and other attached inverts were waving around in the current.
I used to see Sunflower stars, Pycnopodia, roaming across the mud below the dock foraging for urchins, mussels, clams, sea cucumbers, other seastars, but since the seastar epidemic (Seastar Wasting Syndrome) spread all up and down the West Coast in 2014, I’ve seen none here or anywhere else in the islands, and reports say they were wiped out in the Salish Sea in general, even at depth. While other kinds of seastars have started to recover in the past couple of years, Pycnopodia has not, sadly.
However it was thrilling to see an Ochre star (Pisaster ochraceus) on the side of this dock, as bold as you please. These are the most abundant seastars on the West Coast, hence have a prominent influence in marine ecosystems. During the peak of the epidemic, their prey species populations skyrocketed. One consequence was kelp loss due to the increase in sea urchins. Seastars eat urchins who eat kelp. Kelp beds are critical marine habitat, for example as a nursery for juvenile fish and invertebrates. Several factors have caused the decline of kelp beds in recent years, including warming waters due to climate change, and the population explosion of urchins grazing them down to nubs just exacerbated that trend. The recovery of Pisaster seastars has been a very hopeful sign.
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Mostly sunny today in the PNW islands. Temps in 50s. Light breeze.
What’s up in nature in your area today?
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