A cluster of mature sea stars discovered last week near Paradise Cove came as a surprise to the family who came upon them, and to other longtime residents who say they’ve never seen a group of large ones here.

A federal biologist in Juneau said the species, known as mottled stars (Evasterias troscheli) are common in protected waters of Southeast, but maybe not so much around Haines. Also, springtime events, including extreme tides and spawning, mean the creatures are more likely to be stranded on the surface and spotted this time of year.

Mandy Lindeberg, a fisheries biologist with the National Marine Fisheries Service in Juneau, said stars photographed by the Combs family last week appear to be healthy. The creatures – technically not fish but echinoderms – cluster sometimes to feed and other times to breed.

They’re typically found in rocky, intertidal areas near shore and range from Monterrey Bay to the Aleutians.

“It might be that the population is doing really well and feeding or that they were aggregating to reproduce at low tide and got caught. When they’ve got business to do, they all get a little distracted,” Lindeberg said.

Even when caught by a quick-draining tide, mottled stars can survive for hours out of the water, sometimes hiding in kelp.

Mottled stars – which are most commonly grayish green but also can be colored purple or burnt orange – are among the hardiest sea stars and can live where the ocean is influenced by fresh water, which occurs around Haines.

But stars typically like extensive shallows water habitats, which are limited in upper Lynn Canal where beaches drop off precipitously into the fjord.

Mottled sea stars are one of the species suffering from a well-publicized wasting disease, attributed to a virus. While there have been historic outbreaks of the disease, the recent one has been very widespread, Lindeberg said. Scientists suggest warming ocean temperatures may be contributing to the disease and recently in Alaska we have had above normal seawater temperatues.

Lindeberg said information on localized populations of sea stars is spotty and it’s possible that numbers of stars here is increasing.

“Alaska’s extensive coastline is a challenging area to follow changes in species populations and distributions. Often, locals who have lived near a beach for a long period of time can be the best source of information and observing changes. One sighting may be an anomaly, but over many years if there’s something changing, they would know,” Lindeberg said.

The mottled star is one of four sea stars common to the area. The other three are the sun star, the ochre star and the six-rayed star.

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