Have you noticed that whenever you drove by and looked at the beach this month it looked like it was high tide? Recently our local tides have been timed just so that low tide was during the dark and dusk hours of the morning or evening and high tide coincided with daylight hours. I don’t always pay much attention to the tide tables, but this month it mattered because for our annual fifth-grade marine science lessons I needed to go to the beach at low tide and find some sea stars. Don’t worry, I operate under an official collection permit and I only take as many animals as I need and those will live the rest of their days in the touch tank.
Last week, when finally the low tide coincided with the coming of light in the morning, I walked to the beach near my office, equipped with raingear, waterproof gloves, a few buckets and a flashlight. I needed six to eight mottled sea stars and a dozen or so of the common little six-arm sea stars. I was also going to collect a few sea stars of various species to be able to show the students the diversity of sea stars.
I admit I was a little worried the tide was not really low enough to expose my quarry, because as far as low tides go, it was not one of the low low tides. Also, by the time I could see well enough not to stumble over the rocks and break my heels, the water was already coming back. From experience I knew to watch my buckets and not leave them near the water’s edge while getting enthralled with the life in the tide pools.
This day, however, I did not gaze into pools; I was on a mission to find stars to recruit into the educational program. Shining the flashlight along the waterline made the colored sea stars stand out. Soon I found a large specimen of the desired species, the mottled sea star. Then, a sunstar, a cushion star and two rose stars. I also saw a sunflower star and a blood star, which I did not collect.
On the more rocky shore where the climbing got more difficult, the hunting got more successful. After only a little while I had the desired number of mottled sea stars. Also, the beach line was getting smaller and if I didn’t want to have to climb back through the trees or swim, I needed to turn around.
Back where I had started, I quickly collected the needed six-arm sea stars. These are the most common species on our beaches. With only about three inches at full size and a habit of hanging out in packs, one can easily pick a dozen of these little stars off the bottom of one large rock in the upper tide line.
After two trips up the hill with full buckets of water and sea stars, I released my catches into the prepared tank and watched for a while as they settled into their new and strange environment. However, there was one surprise in the bucket. When I lifted the cushion star, it felt as if I had accidentally also picked up a large jellyfish.
Let me explain: A cushion star is about five inches in diameter, but at least one inch thick, looks puffy and has short arms. The one I found is dark brown with a lighter brown pattern and a pale orange bottom. I didn’t look closely enough to see this, but have since read that each stubby arm has a single eye spot at the tip and several tube feet, different from the tube feet used for walking in that they lack suction cups and are used like feelers.
The cushion star is also called slime star. When it feels threatened it releases copious amounts of slime. This slime has a bad taste and wards off predators. Medical scientists are studying this slime, because it contains steroids.
As I read more about different sea stars, I discovered there is one called the morning sunstar, which preys on other sea stars. I did not find one of those and am not sure it lives around Kodiak, but I did find a very close relative, the striped sunstar. I had transported that one in the same bucket as the slime star. It is just a guess, but perhaps the presence of that star scared the slime star into sliming, or perhaps being picked up and rattled around in a bucket provoked the slime response.
I have also read that cushion stars are usually found in deep, dark water, so another guess is it did not like the laboratory lights and answered to them with its slime. Eventually, I placed a basket over the scared slimer, put it into a dark corner of the tank a distance away from the other sea stars and noticed that very soon the sliming stopped.
I have since learned that sea stars try different approaches to get away from a predator like the morning sun star. Our largest sea star, the sunflower sea star, is much faster and can easily outrun the predator. Rose stars, which have their name from their reddish color and pretty looks (they have 10 or 11 short, even arms) are also fast movers and choose flight over fight.
However, the striped sunflower star will push the predator away vigorously, and then try to run. The very slow blood star, when attacked on the wall of a tank will drop off and sink, but I don’t know how that tactic would help in the ocean. Only the cushion star was never eaten in that study, because it had that protective nasty tasting slime.
It almost seems like something out of a children’s cartoon — the slime monster that throws jello at his enemies when he gets scared! One thing is certain: Sea stars are much more than boring things that lie around the rocks. They are such a seemingly simple animal, yet they have so many amazing adaptations.