Sunday, July 26, 2009

One for the Little Guys

One of the best things about the Ucluelet Aquarium is the opportunity to see and appreciate all the little guys that are often missed among the kerfuffles of the sea. It only seems right that the blog should reflect this and here it is: One for the Little Guys. By taking advantage of our microscope and cameras we were able to show off a few of our most-missed buddies.

Calcareous tubeworms (Serpula columbiana) can grow to be up to 6.5 cm long and have a diameter of 0.6 cm. These tube-secreting worms stay encrusted to the rocks for most of their body length and can hide inside their shell when startled. In the below photographit is possible to see the trumpet- or funnel-shaped operculum that the animal uses to block of the entrance of the tube when fully withdrawninto the shell. The aquarium also has feather duster tube worms that when approached with a finger will rush into their softer, more flexible home.These animals are filter feeders that munch on plankton and reproduce by broadcast spawning.

The Sitka Periwinkle (Littorina sitkana) is commonly found in protected intertidal zones trying to stay moist. They often will aggregate as seastars do in an attempt to not dry out. Living similarly to other snails and as the prey of some nudibranchs, the sitka periwinkle can be variable in colourfrom a light brown to black and will often have stripes have various thickness and colour.

The Heart Crab (Phyllolithodes papillosus) lives between the intertidal zone and down to 183 metres. Its camouflaugecomes from the hard spines covering the legs and pincers. They grow to be 10 centimetres across the carapace but as youcan tell in the picture they are quite small when they are young. These guys get their name from the heart-shaped designon their backs.

Little Skeleton Shrimp have been popping about in several tanks as they develop into a size visible with the naked eye. This generic grouping contains several species which can be either filter feeders or predators. These shrimp tend to be found in large groups in our tanks and can be seen attaching on to the algae or rocks and swaying to and fro.

The excitement level of the small common barnacle (Balanus glandula) is unfortunately often lost on local beachcombers- and What a mistake thatis!! These crustaceans begin life as small larvae that contribute to the plankton population as they are released from the shell of the fertilized adult. Each adult will brood and release up to 13 000 larvae at a time. As they mature they are attracted by settledbarnacles towards rocks, pilings, or even animals on which they are able to settle. Once committed to a surface the barnacle willattach itself for life using cement glands in the antennae. Their appendages change into a fan like structure- the cerripeds- and theyconstruct a permanent shell structure in which they will entirely hide when not feeding. They filter the water using their cerripedsto catch all the plankton that they feed on. The funnest fact of all? When it comes to mating the hermaphroditic barnacle will probetheir neighbours with their male reproductive organ which can be up to five times the size of the rest of the body!!

Get your glasses on and come check these little guys out first hand!

-Mary Vasey, Interpreter

No comments: