Nature Watch: The View Down Under

Author: Steve Ellis | 06/26/23

About the author: Steve Ellis is a naturalist and Land Trust member who enjoys sharing his love of the natural world. His blog series, “Nature Watch,” will appear each month in “Habitchat,” chronicling native plants and wildlife you can expect to see during that particular time of year. We thank Steve for sharing his passion, illustrating the importance of island conservation.


Most fish and mobile marine invertebrates spend the winter months sheltering near the bottom of the Salish Sea. July’s warmer water temperatures prompt many of these creatures to migrate up the water column.  Very little of this active sea life can be seen from the shore. The best alternative is to catch the action from a dock or pier.

Sea life on or milling about a dock piling is stratified like the flora and fauna on a mountain. Lower areas provide the most stable environments, while those living near the top endure the harshest conditions.

Acorn barnacles and blue mussels form the base layer for much of the life attached to the upper portions of the pilings. These hardy animals need to survive daily periods of exposure to the air with its hot or cold temperature. Various alga species grow on the aggregations of these shellfish. Snails, chitons and polychaete worms can be seen grazing on this growth; in turn, they often become prey for crabs and fish.

Farther down the pilings are the anemones and tubeworms that require constant submersion. The lowest sections of this vertical habitat host large seaweed and various shellfish.

Fish are the easiest life forms to spot moving about. As many as 30 species can be found under or around piers in the Salish Sea. They congregate for food, protection, and to reproduce. Look for Pacific cod, bay pipefish, starry flounder, several species of sculpins, seaperch, gunnels and juvenile rock fish.

The view down under a dock is superior to that from a boat. Here are a few tips to make your “pier peeping” successful: Many fine field guides and apps are available to help you identify the fish, invertebrates and seaweed. Go on a calm day for prime viewing conditions. High tides are best for fish-spotting. Watch your step and heed warning signs. Do not enter restricted areas.

Here’s a list of public docks in Island County:

Sugar Kelp may reach up to 16 feet in length, growing as much as half an inch per day in winter through summer.

Flora: Sugar Kelp, Saccharina latissima

Sugar kelp, named for a sugar alcohol solution found within, is a species of brown seaweed that can be found growing from pilings.

This common kelp has a single blade (frond) that may reach 16 feet in length and have a width of seven inches. The blade is yellowish to reddish-brown in color (sometimes noted as “milk chocolate”), with a dimpled surface and wavy edges.

Sugar kelp can live two to five years, with its exact age revealed in annual growth rings found in the stipe (stem). It can grow as much as half an inch per day during late winter through early summer.

Reproduction happens year-round, with much occurring in late summer into fall. Spores that will be the next generation are released while the bloom of phytoplankton – single-celled plants, spores and other organisms – is low. This benefits small animals that rely on phytoplankton as food.

Sugar kelp is attacked by a number of herbivores that browse the stipes and blades. Snails feed on the kelp and in turn are prey for rock crabs and other predatory invertebrates. Some smaller clam species nestle in the holdfast or attach themselves to the stipe. Small fish also find shelter under the blades.

Look for sugar kelp attached to rocks at very low tide or tumbled ashore if their rocks became dislodged by storms. Some may be seen growing from pilings such as those found at Cornet Bay.

Shiner perch can be spotted near docks and wharves during the summer months.

Fauna: Shiner Perch (Shiner Seaperch), Cymatogaster aggregata

Shiner perch is a ubiquitous fish species around docks and wharves.

Shiners are four to seven inches long, with an oval-shaped body that’s compressed laterally. The top is grayish, while the rest of the body is silvery. Females have three yellow vertical bars, while the smaller males are mostly blackish over the silver background.

Prey items for this numerous fish species include small crustaceans and other marine invertebrates.  They also nip off the appendages of acorn barnacles and eat fish eggs.

The breeding season is June through August, with females birthing live young. Adult females are usually fertilized soon after, but the development of the next generation is delayed for several months.

Their penchant for congregating near the surface during daylight hours makes them easy targets for predators such as larger fish species, as well as harbor seals, river otters, herons, kingfishers and terns.

In fall, shiners migrate to deeper waters, finding shelter among rocks and in eelgrass beds.

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