May 19, 2024

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I set out to walk mile 340, the northernmost mile in the state of Oregon, because I was curious to document wrackline biodiversity where the Columbia River meets the Pacific Ocean at "Clatsop Spit". Shortly after the morning low-tide, I found dead Dungeness crabs, a large cluster of multiple egg cases of Opalescent Squid, Keyhole limpet shells, vesicled rockweeds in the genus Fucus, sea lettuce in the genus Ulva, Aequorea victoria jellyfish, and purple mahogany clam shells. Moderate amounts of marine debris in the wrackline included plastic bottles and cups, fishing gear, styrofoam, a plastic shotgun wad from waterfowl hunters, and plastic fragments. From the southernmost end of this mile, you can see the 51 foot Cape Disappointment Lighthouse perched on a rocky promontory in the state of Washington. According to USbeacons.com, this lighthouse has a marine navigation range of 21 nautical miles in clear weather conditions (i.e. nominal range), Opalescent squid is the most common taxa of squid distributed on the Oregon Coast. According to NOAA Fisheries.gov, female Opalescent squid in the genus Loligo lay many white, opaque, gelatinous egg cases, and each case may have between 180 and 300 individual eggs. Ideal habitat for egg deposition is sandy benthic zones in the ocean at depths up to 10-15 meters. According to Coastal Watershed Institute, the egg cases are attached to the sandy ocean floor with a sticky substance to anchor them safely. This "biological anchor" provides an attachment point, while facilitating proper oxygenation of the egg cases by ocean waves. I was fascinated to learn that Opalescent squid spawn year-round and that once hatched, the young are called paralarvae. As important secondary consumers in the marine food web, Young California market squid eat small crustaceans, and in turn, represent an integral prey item for many Pacific Northwest fisheries: salmon, rockfish, and lingcod. According to the Seaside Aquarium, spring and summer are important months in the squid's life cycle: large groups of Opalescent squid migrate to shallower, more protected waters to reproduce. In addition, strong westerly winds and upwelling of deep, cold water rising towards the ocean's surface can wash Opalescent squid eggs ashore on Oregon Coast beaches. Opalescent squid play an important ecological role in the marine food web and are classified as mid-trophic level consumers. Interestingly, according to the Marine Species Portal for the state of California, many mollusks and echinoderms consume Opalescent squid eggs, including bat stars, Kellet’s whelks, and chestnut cowries. Marine mammals and seabirds (common murre, rhinoceros auklets, Brandt’s cormorants) prey on Opalescent squid, as well as many species of commercially important fish. An interesting project idea would be to track the relative abundance of egg cases (squid, big skate) washing ashore during the spring and summer months along the Oregon Coast.