Carmet Beach Tide-pooling

Carmet Beach

If you enjoy marine habitats and are looking for a great place to tide-pool, then you should visit Bodega Bay. Bodega Bay is on the coast of the northern California. Bodega Bay consists of a shallow, rocky inlet of the Pacific Ocean. The bay is used for many reasons because of its marine habitat. For example it's useful for its navigation, recreation, and commercial and sport fishing include shellfish harvesting. Bodega Bay has a series of beaches that are separated by rock bluffs and headlands. Carmet beach is one that I personally enjoy visiting. It is a narrow rocky beach that is part of the Sonoma Coast State Park. The beach is right along Highway 1, the parking lot has two steep trails that drop down to the beach on both sides. The southern cove is the widest and sandiest, while the Northern cove extends north along a narrow boulder-filled shoreline. On my latest visit to Carmet Beach on March 7th 2017, I encountered a couple of new species that I hadn't seen before in previous visits. There was also some patterns that I thought were interesting.

Cancer antennarius

On the Southern/right side of Carmet Beach, my classmates and I recorded the water salinity to be about 25.5. While the water temperature was 15 degrees Celsius. On this side of the beach, I observed the different habitats and was mainly tide-pooling. I saw in many amounts, brown red crabs. I hadn't seen this type of species before. This type of crab is known as the pacific rock crab (Cancer antennarius). This type of crab is found in intertidal waters off of the Pacific coast of north America. In areas between San Francisco, California, Baja California and Mexico. C. antennarius are in the low intertidal zone to up to 100 meters. It can be found in both sandy and rocky substrates. When in low tides, they tend to be under rocks and deep within crevices. Every single one of the crabs that I found while tide-pooling were underneath crabs. Something interesting that I did notice, that I constantly saw a pattern of. Was that every single one of the crab I found were underneath rocks and they were in close contact with other species. In every habitat of crab, there were sea stars, barnacles, snails and anemones. The interesting thing was that the crabs were underneath the anemones. It could be either because they enjoyed it or for protection. These crabs are known to have interactions with several species of barnacles and sponges. when crabs move around, the barnacles are able to filter feed. The crabs use the barnacles for camouflage, but sometimes they eat the barnacles. Other food that they tend to eat also include echinoderms. Some of the animals that prey upon the these crabs include sea otters, sharks, octopuses, and large sea bass. The crabs are the most vulnerable to be attacked after they have molted. That is because their shell is soft and the animals have little protection against predators. There is not much studies done on the behavior portion of these animals. But it is indications that they rarely travel more than a few kilometers from the site at which it is released. Their molting process is governed by steroid hormones that are called ecdysteroids. Smaller crabs molt every 5 to 8 months, while larger ones molt every 12 to 18 months. Mating usually occurs in the spring and fall. It is more often done when the female crabs molt because their shells are in a soft condition. When I was tide-pooling I did notice that they did not move much. They are typically more active at night and they prefer higher salinities, which they are found in larger estuaries that are close to oceans.

Anemone, Bat Star and Cancer antennarius

The two types of sea star species that I encountered were the Pisaster ochraceus. Which are better known as the purple sea star, ochre sea star or the ochre starfish. This sea star is known to be a keystone species, which is considered an important indicator for the health of the intertidal zone. Patiria miniata, or better know as the bat star is another of the new species I encountered on this visit to the inter-tidal in Carment Beach. They are usually found in the intertidal zone to a depth of 79 meters. They range from Sitka, Alaska to Baja California in the Pacific Ocean. It is mostly abundant in the coast of Central California and the Monterey Bay. They can be many different colors and they breathe through gill like structures on its back that perform as respirators. They lack pincers that most starfish use to clean their skin surface of debris. Their small cilia may create enough of a water current to keep the surface of its skin clean. They eat their prey by covering them with their stomach and they ooze digestive juices over it. Which liquefies the food and helps for ingestion. They eat both plants and animals. They reproduce through spawning. The males casts sperm and the female drops their eggs. The sperm and eggs unite at sea and they are carried by the ocean currents. Bat stars are usually not with other bat stars. They may gently fight with each other if they meet. They fight by pushing and laying an arm over the other. The bat stars that I did notice that none of the bat stars that I saw were with other bat stars. They did seem to be alone and not being near other species, other than plants and algae. These bat stars are important because they are detritivores and scavengers, they are able to collect algae and dead animals from the ocean floor. Which helps in keeping the ocean healthy.

Bat Star

On the Left/Northern side of the beach, we did more than just tide-pool. We recorded the water salinity to be about 32.5, while the water temperature was 20 degrees Celsius. We see that on this side of the beach the water salinity and temperature are higher than the right side. We did some counts of Pisaster and Bat Stars on a 30M by 4 M mark. Overall we counted a lot more of Pisaster Stars than we did Bat stars. There was about eleven juvenile Pisaster Stars and thirteen adult Pisaster Stars. There were about two juvenile Bat stars and one adult Bat star. There was no Pisaster sea star that I found alone. They were always in clumps or in close range to each other. They are mostly found in mussel beds and on rocky shores. While juveniles like to be in crevices and under rocks. The adult Pisaster's that I found were on rocks, while the juveniles were under rocks. I had to look harder and smarter to find the most of the juvenile ones I found. In the other hand, I did notice that the Bats were not necessarily on rocks or crevices. They were on the sediment and not really attached to anything for support. They were much easier to grab and hold. It is very important that if an animal is grabbed, then they should be put back in their initial habitat and position. It is also very important that we are very careful when tide-pooling and observing marine habitats. That is because we do not want to harm or get in the way of these animals. So, please be very careful and gentle when exploring any marine habitat. Whether it's Carmet Beach or any other place.