Herring Spawning

One of the great spectacles in North American wildlife watching is the Pacific herring spawning. It happens every year in late winter and early spring. Not only does the event produce the next generation of an important fish species, it also sustains the current generation of many other animals.

Pacific herring form an important strand in the food web. They are classified as forage fish, meaning they serve as meals for larger fish like salmon. As we'll see a little later, herrings feed the larger community beyond just the salmon.

Herring spawning turns the sea white (Prince William Sound Conservation Center) 

Herring move to shallower seas during spring, which happens to be right around the same time hungry humpback whales arrive from the tropics. The herring are looking for eelgrass or kelp beds for their sticky eggs to attach to. After the females lay their eggs over the vegetation, the males swim over and release their milt to fertilize the eggs.

Before reaching the spawning beds, the herring must navigate a maze of predators: sea lions, sea birds like cormorants and gulls, bald eagles, and those hungry, hungry humpbacks. Once the work is done, the eggs aren't safe and the smorgasbord continues as diving ducks pick them off. About two weeks later, the remaining eggs hatch and the herring larvae are carried by the tide and are subject to predation by fish of all shapes and sizes.

Herring eggs attached to kelp (US Geologic Survey)

With all that eating going on, it's a wonder any herring survive to adulthood. Females typically lay 20,000 eggs a year, and if she lives a long life, she'll do this three times. Multiply her by a million of her closest friends, and you have about 20 billion eggs. If only 1% hatch, that's 200 million baby herring.

Sea lions await their feast (Tillamook Coast)

In a good year, spawning herring will color the sea white. However, the spawning isn't nearly as good as it used to be. Overfishing is one reason, but loss of habitat (spawning and feeding areas) and pollution are also big contributors.
This week's information comes from Wayne Hoffman, Ph.D. and Washington Department of Natural Resources.
nm1: Prince William Sound Conservation Center https://pwssc.org/herring-spawn/
nm2: USGS https://www.usgs.gov/media/images/pacific-herring-eggs-macrophytes
nm3: Wayne Hoffman https://tillamookcoast.com/blog/spawning-of-pacific-herring/

Reef Madness

Last week we explored the dynamic barrier islands, a great place for wildlife and a popular vacation destination. This week, we venture beyond the island into the coral reefs just offshore. As an avowed landlubber, I'll probably never get to see a coral reef for myself, but I'll live vicariously through myself telling you all about them.

Coral reef (Smithsonian)

Coral reefs are hard, rocky structures made of the skeletal remains of what was once living coral. Corals are a marine animal, not a plant, and the best-known form a symbiotic relationship with algae. Because algae needs sunlight for photosynthesis, many coral reefs are found in clear, shallow water. Cold water corals that live in the deep sea. Without sunlight, these organisms filter feed plankton. Because of their inaccessibility, we are still learning about them.

Coral polyps (NPS)

The most popular corals are the shallow ones, because they are relatively easy to reach. Scuba diving, snorkeling, and even glass bottomed boats bring humans right to the biological hot spots. People are drawn to coral, not just because of the beauty of the coral itself, but the amazing biodiversity found within the reef. Fishes, crustaceans, sponges, anemones, and countless other sea creatures call the reef home. The coral structure provides hiding places for mobile critters and anchorages for sessile ones. Hiding places benefit predator and prey alike- they provide somewhere to hide from bigger fish, or place to launch a quick strike at an unsuspecting meal.

Coral reef (NPS)

Cold water corals provide the same habitat and ecosystem, and may be even more important than their shallower counterparts. Most sea life can be found near the coast and relatively shallow. Corals in the deep sea for a sort of island in an area that is otherwise mostly devoid of life.

Deep sea cold water coral (Joint Nature Conservation Committee)

Like just about every ecosystem in the world, coral reefs are in trouble. Coral is dying as sea temperatures and carbonic acid levels rise. The algae component of the coral either dies or evacuates in a process known as coral bleaching. Some corals show some resistance to slightly warmer temperatures. Research into this is continuing. If you ever get a chance to explore coral reefs, either by boat or underwater, remember to look but don't touch.
This week's information comes from NOAA and the Smithsonian Institute.

Keystone Species

Ever come home at the end of a long week at work, wondering how the place could function without you? It might feel like you’re the only one holding it all together, like a keystone. This week we’ll take a look at the keystone that holds an ecosystem together- keystone species. Without the keystone species, the ecosystem would collapse, or at least be severely altered.

Examples of keystone species are the gray wolf, limber pine, and sea otters. We’ll take a quick return trip to the lava fields of Idaho, then the kelp forests of the Pacific coast to see how limber pines and sea otters are the keystones of their neighborhoods. We learned about the gray wolf and the good work they do at Yellowstone back in September here.

The limber pine is one of the few trees I saw growing at Idaho’s Craters of the Moon National Monument and Preserve. Back in September I spotlighted Craters of the Moon in “Volcanic Idaho”. In that blog post, I mentioned the diverse ecosystem found there. Much of it centers around the limber pine. Limber pine is a pioneer, one of the first to colonize an area following a disturbance, such as a volcanic eruption in Idaho. Its seeds, needles, and sap feed a multitude of mammals, insects, and birds. Without the limber pine, those critters would have to live elsewhere in Idaho, maybe even Utah or Wyoming.

Limber pine at Craters of the Moon

Off the Pacific coast, one of the most important marine habitats is the kelp forest. The kelp hosts many species of fish, somewhat resembling a coral reef (sans coral, of course). The kelp also absorbs storm surge and carbon dioxide. However, kelp tastes delicious, at least according to sea urchins. Lucky for the kelp, sea otters think sea urchins are delicious. Without the otters keeping the urchins in check, the kelp forest becomes an undersea clear cut. Local biodiversity plummets.

River otters (Marine Mammal Commission)

Kelp forest with and without sea otters (Sea Otters.com)

This week's information comes from Great Ecology's blog on limber pines and Sea Otters.com