You can't go to the beach without seeing any animals. It's impossible unless you're on the Moon or Mars. Here's some animals to look out for while tidepooling"
Splash Zone - tides 5" and above
Even if the tides are very high, some spectacular animals may be seen. By looking near the top of the beach, you may see a snowy plover. These fluffy white birds are becoming less popular due to their undisturbed beaches becoming open to the public. When you see them, don't disturb them or even feed them. If the tide is high but you still hope to see a critter, go down to where the water meets the shore and look in some seaweed. Inside, you might find a shrimp like animal called the California Beach hopper. At first, it may look like a brown, hopping flea with large eyes and red antennae, but it is actually an animal related to shrimp and crab. It comes out at night to feed on the seaweed in the Splash zone. However, It cannot survive underwater, and therefore isn't considered a "sea creature."
But let's say you wanted to see an actual sea creature. Well, if you go to a beach with some rocks and algae, chances are you'll find an Eroded Periwinkle. This gray/light brown small snail has many crazy adaptations. Since it lives in the splash zone, it can stay out of water for a long time. When the tides go down, it traps water in it's shell and closes it with a trapdoor called the operculum. Sometimes, it can live out of water for up to 3 months! In some occasions, the snail will never go back in the saltwater, and live for a few days on a dry rock. The name "eroded" comes from the shells condition. Many of the times, the shell appears eroded by the surf. The thick calcium keeps it from getting completely eroded.
High Intertidal Zone - tides 4" to 3"
Let's say the tides are a bit lower than 4 feet. While a bunch of people would leave, there are a bunch of animals that are still exposed. The Rough limpet is a type of cone shaped snail that is suctioned to the rocks. That way, seagulls can't peel it off for a meal, and the waves won't wash it away. Rough limpets are often found with other limpets out of water on the rocks. Rough limpets, like Eroded Periwinkles, can live out of the water for a long time. When an animal like a starfish does it it, a visible scar on the rock can be seen. Limpets scavenge for algae at night, and after they've been staying put for a long time, a scar in the shape of the shell forms on the rock.
Striped Shore Crabs are also found on the High intertidal zone. Look in any crease or flip open a rock to find this little crabs. The males are generally bigger than the females, who can carry up to 50,000 eggs! Striped Shore Crabs bubble when they are out of water, which can be up to 4 hours. Many animals who spend the most time exposed can stay out of water for longer.
Dogwinkle snails, mussels and Anemones are sometimes found in the higher intertidal zone.
Mid Intertidal Zone - tides 3" to 2"
The mid intertidal zone is home to the California Mussel. When these mussels are detached from their rock, they create a byssus, which is a type of string emitted from the mussel. The mussel uses these byssus to connect to another rock or mussel when detached. California Mussels can live up to 30 years and can reach a length of almost 6". They provide a home for snails, bryozoans, fingernail limpets, crabs, shrimp and barnacles, who are often living on the shells of the Mussel.
Barnacles seem like boring bivalves but they are not! They are crustaceans, which are related to crabs and lobsters. They use a brush like limb called cirri to sweep plankton in through their mouths. Some barnacles grow on snails, boats and docks.
The Purple Shore Crab and various rock crabs can be seen hiding under rocks here and there. The Purple Shore Crab is less flat than the Striped Shore Crab. It is significantly slower when running, and is often found in the water than out. The purple Shore crab has a beautiful magenta carapace that can sometimes be olive green, brown or white in juvenile stages. Seagulls and Raccoons eat this crab when it comes out at night.
Aggregating Anemones are often seen at sites where there is a heavy surf. Sometimes, they are called "surf anemones" for that same reason. These Anemones can split into two when necessary. Both halves become new anemones! Anemones that aggregate on rocks are usually a result of one individual cloning multiple times, and those clones cloning as well. Surf Anemones sometimes have battles between different territories. They use a special stinging cell called a nematocyst to sting other anemones and prey. The sticking sensation you feel while touching an anemone is the result of nematocysts. Your skin is too thick to feel the anemone stinging. They eat decaying animal matter, like dead mussels and crabs.
Black Turban Snails and Chitons, both which are Bivalves, are also found here in the mid intertidal.
Low Intertidal Zone, anything below 1"
In the lowest of all tides, the most animals can be found. The Ochre Sea Star is one of many. These common sea stars can be orange or purple, and can grow to 10" in diameter. They eat mussels and anemones, which keeps the ecosystem healthy.
Sea Urchins, Brittle Stars and Sand Dollars are usually uncommon, until the tides reach below -1 feet, where they can occur in high densities. They are related to Sea Stars, in the Echinoderm family. Purple Sea Urchins are stereotypically found with kelp in the deep water. However, they are occasionally found in tidepools, where they use their sharp spines to dig into the rocks. This hole they make protects it from the rough sea. Brittle stars look like sea stars, except they are much floppier and their arms are flexible pieces of rope. This way, they can slip underneath rocks and hide with ease. Sand Dollars are like Sea Urchins, except their spines and tentacles are reduced to tiny strands of hair. They have flat hard, purple shells. Sand Dollars live in deep waters with half of their body sticking angularly out of the sand. Occasionally, you might see it in the tidepools Unlike the other echinoderms, who feed on meat, sand dollars feed on microscopic algae called plankton. Due to it's lack of movable body parts, if one is flipped over, it cannot right itself back; and will therefore die. That's why most of the sand dollars are dead on the beach.
And That's it! Be sure to look for these animals in your next tidepool visit!
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