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Archive for the ‘Crabs’ Category

Terrific tides, crab opener, and croaker care

Friday, June 29th, 2012

Students and families at Scenic Beach State Park. Photo: Jeff Adams

Terrific tides
This morning was the first in a great set of minus tides.

  • 6/29, -0.4 at 7:43AM
  • 6/30, -1.6 at 8:36AM
  • 7/1, -2.5 at 9:27AM
  • 7/2, -3.1 at 10:16AM
  • 7/3, -3.4 at 11:03AM
  • 7/4, -3.2 at 11:50AM
  • 7/5, -2.7 at 12:35PM
  • 7/6, -1.7 at 1:20PM
  • 7/7, -0.5 at 2:04PM

Remember that these are predictions for Seattle and can vary depending on geography and weather. Should get you in the ballpark though. Kitsap Beach Naturalists will be on several beaches at different times over the next week if you can take advantage of the great critter stories they have to share.

Eagles know where to find midshipmen. The medium to large rocks such as those in this image often harbor midshipman during the summer. Poulsbo waterfront. Photo: Jeff Adams

When you head out to explore the beaches, keep a few things in mind to protect and respect those who call the beach home.

  • tread lightly and walk more than run (you stay safer and see more cool stuff when you’re walking anyway),
  • look around the edges of eelgrass and kelp beds instead of tramping through them,
  • explore mostly under rocks that are smaller than your head and return them to the way you found them,
  • refill any holes you dig, and
  • remember, shellfish license or not, it’s illegal to take most living sea creatures off the beach, including  shore crabs, hermit crabs, sea stars, sand dollars, snails, etc.

Midshipman eggs with the front half of daddy midshipman cryptically visible to the lower left of the eggs. Fort Ward. Photo: Jeff Adams

Midshipman (croakers)
In the big rock category, if you do turn over a large rock this time of year, you may find male plainfin midshipman (Porichthys notatus) guarding pea-sized yellow eggs that are attached to the underside of the rock. It’s a really cool thing to see, but over-handling of the fish and awkward replacement of a heavy rock may be tough on the fish and it’s progeny. If you do get a good look at one, maybe stick to the “rocks smaller than your head” rule and leave the rest of the large rocks be.

These amazing deeper water fish have light producing spots called photophores under their head to attract prey, and some seriously sharp teeth with which to munch them. Each late spring/summer, they rise up to the intertidal to stake out nests under large solid objects and make grunting noises to attract the ladies (the reason they’re sometimes called croakers).

Midshipman, nibbled on and left to dry. Poulsbo waterfront. Photo: Jeff Adams

Plainfin midshipman are important predators, but also fall prey to seals and sea lions and can be a very important part of eagles’ diet. It’s not unusual to find the bodies of eviscerated midshipman far from the shoreline, delivered there by an eagle or crow. They are also sometimes abundant bycatch in commercial shrimp trawls.

Crab season
For those of you who have been drooling for dungeness since Christmas… The recreational crab season opens this Sunday, July 1st, for much of Puget Sound and lasts until September 3rd. Blain/Bellingham/San Juans are the exceptions with a slightly later start and close to the season. You can only crab Thursdays, Fridays, Saturdays, Sundays and Mondays. I guess Tuesday and Wednesday is the crab weekend.

The large hard substrate that midshipman find isn't always limited to rocks. Silverdale Waterfront Park. Photo: Jeff Adams

You’re still measuring between where the outermost points meet the carapace. In Puget Sound, you’re looking for up to 5 male Dungeness that measure at least 6.25″, and up to 6 red rock crabs of either sex that are at least 5″. Make sure their shells are hard and that you record your Dungeness. For crab sexing, you can check out an earlier post, and for lots of great information including gear and regulations, see WDFW’s excellent recreational crab site.

Enjoy the holiday week and the excellent tides, and our intertidal treasures!

Jeff Adams is a Washington Sea Grant Marine Water Quality Specialist, affiliated with the University of Washington’s College of the Environment, and based in Bremerton. You can follow his Sea Life blog, SalishSeaLife tweets, FaceBook and video posts, send email to jaws@uw.edu or call at 360-337-4619.


Thingy Thursday: Catch cards and a confounding crab

Thursday, September 22nd, 2011

Few of us get a chance to see the full diversity of the Salish Sea’s crabs. Many species never venture onto the beaches. Others are small and hide well. Some even remain tucked away inside a large clam or mussel. For all the wonder, economic benefit and gastronomical pleasure crabs provide, there are several species that we don’t want to see in our waters, including the invasive European green crab, Chinese mitten crab and Asian shore crab.

European green crab (Carcinus maenas), notice the five large points on either side of the front of the carapace. Photo: Jeff Adams

Such invasive species can have dramatic economic and ecological consequences. That’s why I’m always very appreciative of folks who send notes or pictures or specimens of something unusual. Controlling the spread of marine invasive species is difficult at best, but the earlier they’re detected, the better chance we have.

I received images of a potential green crab in late August from an informed individual who had found an unusual crab at Birch Bay State Park (near Blaine and the Canadian border).

The European green crab has been present on the outer coast of Washington and up the Pacific side of Vancouver Island since the late 1990′s, but the populations have not been highly successful to date and have not found their way into the Salish Sea. Hopefully, that arrangement will continue since these buggers consume shellfish and outcompete Dungeness crab of similar size, for both food and habitat. Red rock crab on the other hand, tend to give the green crabs a serious abdomen whooping.

Green crab??? Thankfully not. Photo: Len Vandervelden

Fortunately, this is a helmet crab. It has the few large points on the front of its carapace like a green crab, and was probably a similar size (~3″ across the carapace), but helmet crabs are covered in stiff hairs and have points all the way around the back side of the carapace.

Helmet crab (Telmessus cheiragonus), a hairy or even bristly crab with several large points on either side of the front of its carapace and a couple more on the back side. Photo: Jeff Adams

The helmet crab is probably the species most commonly mistaken for a green crab. The individual in question is particularly tricky to identify since it has so many barnacles on it.

Live helmet crabs and even molts may seem unusual even to experienced beach goers. I see scores of them while snorkeling over eelgrass that’s exposed at low tide, but I rarely see them alive on the beach when the tide is out. I guess it’s no surprise that as one of the fastest Pacific Northwest crabs, a helmet crab would rather retreat with the tide than try its luck hiding from gulls in the eelgrass and algae.

Back to the European green crab… Fortunately, it isn’t living up to the initial concern in our state, but there are a lot of unknowns if it gets into the Salish Sea or if conditions change in our waters. It’s certainly important to keep a watchful eye.

Always feel free to send observations, pictures or thoughts of things extraordinary or out of the ordinary. If I can’t share part of its story, I enjoy looking for someone who can and learning together.

Oh, and just a reminder for all you crabbers… Whether you caught Dungeness or not, don’t forget to put your Puget Sound crab catch cards in the mail or enter the data online by October 1 to avoid a $10 penalty and to help managers determine how much crab should be harvested in the winter season. Happy autumn!

Jeff Adams is a Washington Sea Grant Marine Water Quality Specialist, affiliated with the University of Washington’s College of the Environment, and based in Bremerton. You can follow his Sea Life blog, SalishSeaLife tweets and videos, email to jaws@uw.edu or call at 360-337-4619.


Keep the butter out of your belly and your shovel out of the sand

Wednesday, August 3rd, 2011

Screen shot of the Washington Department of Health Shellfish Safety map for Kitsap County for August 3rd, 2011.

Thanks to Paralytic Shellfish Poisoning (PSP) toxins produced by microscopic marine algae… King and east Kitsap Counties are closed to harvest of all shellfish species including clams and geoduck, oysters, mussels, and other invertebrates such as the moon snail (which are no longer legally harvestable anyway).

The meat from crabs is not known to contain the PSP toxin. The guts (butter) can contain PSP levels that are not safe, so carefully clean your crabs and toss the guts. (I guess I’d better stop letting the chickens gobble the guts lest I wake up to a poultry Jonestown.)

Invasive purple varnish (mahogany) clams hold the toxin longer than any other bivalve in the region. Butter clams also hold onto the toxin for longer than most shellfish. Sometimes shorelines will be closed to varnish clam only or to both species only, so read the health maps and warnings carefully. Even when beaches are open, it’s a good idea to cut off the black tip of the butter clam’s siphon before eating it since toxins are concentrated in the tip.

The DOH clickable shellfish biotoxin/pollution map is an excellent resource to check every time you head out for shellfish or might interact with others who are digging dinner. You can also learn more about the toxin and it’s origins from the Department of Health PSP fact sheet and the links it provides.

Noctiluca bloom in West Seattle (late June 2011). Photo: Jeff Adams

Washington Sea Grant also has a really great publication called Gathering Safe Shellfish: Avoiding Paralytic Shellfish Poisoning. The document has lots of great info and fabulous black and white drawings of some of the harvested shellfish species in the Salish Sea (great identification resource). It also discusses the difference between the striking blooms you may see and those creating biotoxins.

This too shall pass. In the meantime… enjoy the the beaches in Puget Sound’s Main Basin, but but keep the butter out of your belly and your shovel out of the sand.

Jeff Adams is a Washington Sea Grant Marine Water Quality Specialist, affiliated with the University of Washington’s College of the Environment, and based in Bremerton. You can follow his Sea Life blog, SalishSeaLife tweets and videos, email to jaws@uw.edu or call at 360-337-4619.

 


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