Aug 04, 2018

Field Updates July 2018: Reports, Mollusks in Eelgrass, and Fish in the Creeks

 

 

Fulfilling our mission to protect and restore the Morro Bay estuary for people and animals requires a lot of hard work in the field. At the Estuary Program, that often means spending time doing research and monitoring work out on the water. Read on to see what we’ve been up to during the past month.

Data and reporting

July was a quiet month for fieldwork. This has given the monitoring staff time to get caught up on data entry and report writing. Keep an eye out for a series of reports related to the health of the estuary and watershed that will come out later this year. In the meantime, you can check out our library to see past reports.

Eelgrass monitoring and mollusk sightings

We did get out to help Cal Poly monitor eelgrass in Morro Bay. While we were out, we spotted a few different types of mollusks.

We often see Navanax inermis, commonly referred to as just navanax.

Navanax inermis is commonly spotted on the mudflat or in eelgrass beds of Morro Bay.
Navanax inermis is commonly spotted on the mudflats and in eelgrass beds of Morro Bay.

We also saw a number of green slugs camouflaged on blades of eelgrass.

It's easy to miss this little slug. It's very similar in color to eelgrass and the same width as the blade.
It’s easy to miss this little slug. It’s very similar in color to eelgrass and the same width as the blade.

This little slug lives on eelgrass and eats organisms growing on the blades. The scientific name for this green slug is Phyllaplysia taylori. We’ve heard a few common names for it, including the eelgrass sea hare or the eelgrass slug. If you break it down, the scientific name is similar. “Phyll-” comes from Greek and refers to leaves or leaf structures, and “Aplysia” is a genus, or category, of sea slug.

Scientific names like Phyllaplysia taylori, come from the system of biological classification called taxonomy. In this system, scientists place organisms in different categories based on their characteristics. The diagram below shows where the red fox falls in each taxonomic category.

The diagram above shows how the red fox is classified and named based on its biological relationship with other organisms. This process of biological classification is called taxonomy.
The diagram above shows how the red fox is classified and named based on its biological relationship with other organisms. This process of biological classification is called taxonomy.

Taxonomic fun fact: People often use the term “nudibranch” to refer to all sea slugs. Nudibranch actually refers to animals that fall within a specific order, Nudibranchia. Neither the navanax nor the eelgrass slug are nudibranchs, because they fall into a different order, Anaspidea. We do see nudibranchs in Morro Bay though, such as this one, a Hermissenda crassicornis

We commonly spot this nudibranch, Hermissenda crassicornis, in depressions along the mudflat.
We commonly spot this nudibranch, Hermissenda crassicornis, in depressions along the mudflat.

Water quality and fish in Pennington Creek

While out doing some routine water quality monitoring, Karissa saw a school of fish swimming around in this pool on Pennington Creek. Pennington Creek has some of the best habitat for steelhead trout in our watershed.

Vegetation lines the banks of Pennington Creek, helping to keep the water cool and well-oxygenated for fish and other wildlife.
Vegetation lines the banks of Pennington Creek, helping to keep the water cool and well-oxygenated for fish and other wildlife.

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