Mission: Sea Star

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Photo by VS user StarfishNursery
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Photo copyright Caitlin Del Sesto / URI
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Photo by VS user 000037

Research Question

Are sea stars declining in the Gulf of Maine’s intertidal zone?

You're invited

Scientists, including GMRI scientist Adam Baukus, have noticed fewer sea stars than they did in the past. Are sea star populations declining across the Gulf of Maine? Is there a cause for a decline, or are populations simply in normal fluctuation? There are a few different hypotheses that need investigating!

Hypothesis #1: Invasive Tunicate
Sue Richman and her students at South Portland High School have noticed fewer sea stars every year and more invasive leathery sea squirts (Stylea clava). They are concerned that the invasive sea squirt is somehow connected to their observed decline in sea stars in their area.

Hypothesis #2: Disease Outbreak
Outbreaks of a mysterious disease have been destroying sea star populations on the West Coast, known as Sea Star Wasting Disease(SSWD). Shoals Marine Lab biologist Robin Hadlock Seeley is interested in potential impacts of the observed East Coast version of the disease which has similar symptoms to SSWD.

In order to determine if sea stars are actually declining in the Gulf of Maine and what might be causing it, Sue’s students, Adam, and Robin are going to need a lot more data. They need your help!

Mission Steps

  1. Print a coastal survey datasheet and the species cards for Northern sea star and Forbes sea star
  2. Go into the field and collect data
  3. If you find sea stars, take note of how many you see or how much of your research area is covered
  4. Post your data... found or NOT found!
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Photo by Fisheries and Oceans Canada CC:BY-NC-SA

Why this mission matters

Sea stars are important predators in the intertidal and subtidal zones and we need to know more about how their populations are changing. Help us monitor sea star populations over time!

Dig deeper: Help Robin Hadlock Seeley Investigate Sea Star Disease

Sea Star Wasting Disease (SSWD) is the term scientists use to describe a condition that affects sea stars where they get white lesions, lose arms, disintegrate, and eventually die. Symptoms of the disease have been seen before, once in 1972 and again in 1978, and now it looks like the disease is back. Many scientists are worried about sea stars since SSWD has struck the Pacific coast, causing massive die offs. In 2013 there was a similar outbreak in the Gulf of Maine and Mid-Atlantic. A recent study by Cornell researchers finally cracked the case on what was causing the disease in the Pacific. Right now it is unknown if the disease on the East Coast is SSWD or something else entirely.

By finding healthy or sick sea stars… or none at all, you help scientists collect valuable data which can help them investigate this disease.

How to help:

  1. Go looking for sea stars as above. ATTENTION DIVERS! Please see this survey protocol from UCSC, your version is special
  2. If you find sea stars, are they firm and healthy looking, or are they mushy, missing arms, or covered with white lesions? Compare the images of healthy sea stars on your ID cards to these pictures if you aren’t sure. Also, please measure the length of the longest arm.
  3. Mention any symptoms of the disease you did or did not find in your Vital Signs data.
  4. If you can, keep returning to the same location so that you can collect data over time.

Dig Deeper: Help Sue's Students Investigate Stylea clava

Stylea clava or leathery sea squirt, is an invasive tunicate that has been impacting coastlines around the world. Native to the Northern West Pacific, it has been found in many other places including the Gulf of Maine. Leathery sea squirt has become a real headache for many people due to its ability to encrust hard surfaces like boats and fishing gear - a problem referred to as biofouling.

Sue's students were curious if too much leathery sea squirt means that sea stars have less habitat to forage in. They noticed that sea stars avoid, or are unable, to attach to surfaces that have leathery sea squirt on it.

How to help

  1. Print out a species card for leathery sea squirt
  2. Go into the field to look for sea squirts
  3. If you find leathery sea squirt, do you see any sea stars? Make note of your findings in your field notes
  4. Post your data... found or NOT found!