Tag Archives: biotic association

Melobesia mediocris: Seagrass Crust–The Race Rocks taxonomy

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melobesia

Melobesia mediocris on Phyllospadix sp.

 

phyllospadixMelobesia mediocris or the seagrass crust is a pink coralline algae which grows as an epiphyte on the surfgrass Phyllospadix sp. 

Kingdom: Plantae
Phylum: Rhodophyta
Class: Florideophyceae
Order: Corallinales
Family: Hapalidiaceae
Genus: Melobesia
species: mediocris
Other Rhodophytes or Red Algae at Race Rocks

taxonomyiconReturn to the Race Rocks Taxonomy and Image File
pearsonlogo2_f2The Race Rocks taxonomy is a collaborative venture originally started with the Biology and Environmental Systems students of Lester Pearson College UWC. It now also has contributions added by Faculty, Staff, Volunteers and Observers on the remote control webcams.Garry Fletcher

 

Mesophyllum sp.: epiphtic coralline algae–Race Rocks Taxonomy

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mesophyllumbad

Mesophyllum sp.Photo by Ryan Murphy

mesophyllum

Ryan Murphy photographer pointing to the the round epiphyte

Classification:
Phylum: Rhodophyta
Class: Rhodophyceae
Order: Cryptonemiales
Family: Corallinaceae
Mesophyllum sp.

Description: This plant is erect, up to 2 cm. wide. Its colour is dark pink to purple. Shape is circular. It exists as a flattened growth epiphytic on many geniculate rhodophytes such as Bossiella sp.
Habitat: On geniculate rhodophytes in tide pools.
Pacific Coast Distribution: Alaska to California.
Other Rhodophytes or Red Algae at Race Rocks

taxonomyiconReturn to the Race Rocks Taxonomy and Image File
pearsonlogo2_f2The Race Rocks taxonomy is a collaborative venture originally started with the Biology and Environmental Systems students of Lester Pearson College UWC. It now also has contributions added by Faculty, Staff, Volunteers and Observers on the remote control webcams. —Ryan Murphy

 

Synoicum parfustis: peach-coloured compound tunicate–The Race Rocks Taxonomy

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Photo by Ryan Murphy

Photo by Ryan Murphy

The small dark spots embedded in the matrix of this Synoicum parfustis are living commensal organisms: the compound tunicate amphipod, Polycheria osborni. This amphipod lives in various compound tunicates.

 

Other Members of the Subphylum Urochordata at Race Rocks 
taxonomyiconReturn to the Race Rocks Taxonomy
and Image File
pearsonlogo2_f2The Race Rocks taxonomy is a collaborative venture originally started with the Biology and Environmental Systems students of Lester Pearson College UWC. It now also has contributions added by Faculty, Staff, Volunteers and Observers on the remote control webcams.

October 2015 (PC)

Biotic Asociations at Race Rocks

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The California Sea Cucumber exhibits an escape response when approached by the Sunflower Star.

Also see the video on Phyllospadix and its biotic associations

This mussel will no doubt have a competition for food with this barnacle.

Mussels have a number of associations.
  The whale barnacle living as a commensal on Gray Whales
You will find below a set of photos from our photo archives depicting two or more organisms in a biotic association. These associations fall into one of several categories: mutualism, commensalism, parasitism etc. By going through the many organisms in the Race Rocks Taxonomy, you will find explanations for these and other biotic associations.
Coraline Algae and Epiactis Boring Sponge (Cliona) and Purple- Hinged Rock Scallop (Hinnites) Cup Coral (Balanophyllia) Epiactis and Encrusting Algae (Lithothamnion)
Basket Star and soft coral
 Basket Star and sea urchin
 Abalone (Haliotis) and Lithothamnion
Anthopleura xanthogramica with internal green coccoid algae Brittle Star and Kelp Holdfast Brittle Star
Nudibranch and the orange hydroid Garveia Swimming Scallop and Encrusting Sponge Scallop with blue eyes

Myxilla incrustans: incrusting sponge– The Race Rocks Taxonomy

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This sponge can be found on rocky subtidal areas at Race ROcks  It commonly grows over the surface of swimming scallop shells. It is believed to form a mutualistic association with the swimming scallop, obtaining a moveable substrate while preventing predation of the scallop. Apparently the smell of the sponge deters the sea stars which may be intending to prey on the scallop

crustsponge

The volcano-like oscules on the sponge which is attached to the valve of a swimming scallop.

ah052010scallopl

Adam harding took this photo off the docks at Race Rocks. The shell of the scallop is covered with the orangish layer of sponge with attached hydroids.

It is an extremely variable widely distributed species ranging from intertidal to 2540 m
Colour: the colour in life ranges through various shades of gold occasionally to a light gold-brown with a slight tinge of rose. In alcohol the sponge is grey-white to yellowish-brown.
Form: The sponge is incrusting or occasionally massive
Size: Intertidal incrusting forms re up to 8 cm thick an 20 cm in diameter. Dredged massive forms have a diameter of up to 9 cm. Fistules are up to 25 mm high.
Consistency: the consistency is moderately firm and tough. some specimens are weakly spongy and fragile.
Surface: The surface varies from slightly roughened and tuberculate to highly rugose and fistulated. It is somewhat rough to the touch
Oscules: oscules are common or abundant and irregularly distributed. Oscules may be elevated on fistules when the latter are present. Oscules are from 033 to 8 mm in diameter.
Pores: pores are abundant and measure from 20 to 270u in diameter.

 

rmincrustingsponge

Detailed view of the incrusting sponge on a swimming scallop

rmincrusting

Ryan Murphy took this image of the various colours of the sponge

Domain Eukarya
Kingdom Animalia
Phylum Porifera
Class Demospongiae
Order Poecilosclerida
Family Myxillidae
Genus Myxilla
Species incrustans
Common Name: incrusting sponge

 

This file is provided as part of a collaborative effort by the students of Lester B. Pearson College
 Oct 2003 Roberto Ruglio year 30

Pterygophora californica -brown algae- The Race Rocks Taxonomy

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“The number of living creatures of all orders whose existence intimately depends on kelp is wonderful…I can only compare those great aquatic forests…with terrestrial ones in the intertropical regions. Yet if in any country a forest was destroyed, I do not believe nearly so many species would perish as would here from the destruction of kelp”

Thus commented Charles Darwin on kelp. Pterygophora californica commonly known as stalked kelp) which is part of the great kelp family that act as the trees of the oceans. This species is present, amongst other places, at Race Rocks.

BIOTIC ASSOCIATIONS: Ryan Murphy, (PC yr 26) obtained a grant from Mount Allison University in June of 2002 to help him do a project on macroalgae at Race Rocks. In this video below , he captures some of the many epiphytes growing on the perennial Pterygophora californica, a brown algae which grows sub-tidally to a depth of 12 meters at Race Rocks. It is a valuable habitat for the many invertebrates in the subtidal and serves as a buffer to storm surges. From June 2-14 a group of students from Pearson College stayed at Race Rocks for the Johan Ashuvud project. Meet the webcrew here

 

Like other kelp species, this one can mostly be found in subtidal zones. It occurs in subtidal zones mostly up to 12 meters of depth. It is mostly found therefore in subsurface canopies of kelp forests. For this reason it is able to live well around the islands of Race Rocks. The Stalked Kelp grows up to 2 meters in length. It has a straight or gnarled, woody undivided stalk and smooth , strap-like blades extending on opposite sides from the top half of the stalk . The end of the stalk results in a terminal blade with midrib and the stalk develops rings as the years go by similar to those of a tree. Pterygophora is an excellent example of a long -lived perennial seaweed. The blades usually degenerate or wear away in winter and new ones are produced each spring. Often, violent winter storms tear up some of the anchored kelp and deposit it on beaches as in the photo above.

Stalked kelp can reach an age over 17 years. It is possible to find out the exact age of a stalked kelp plant by cutting it down (best to use drift ones that are already detached) and counting the rings in its stalk. At Race Rocks this type of kelp provides habitat for a number of fish and invertebrates and a large community of epiphytic algae.

Domain: Eukarya
Kingdom: Protoctista
Phylum: Phaeophyta
Class: Phaeophyceae
Order: Laminariales
Family: Alariaceae
Genus: Pterygophora
Species: californica (Ruprecht)
Common Name: Stalked Kelp

Description:  This plant has a large stout holdfast of branched root-like structures, and a woody stipe up to 2 m. long and 2 cm. in diameter.  The stipe is terete below and flattened at the apex.  A terminal flat, smooth blade arises from the apex of the stipe; it is linear, 6-10 cm. wide, 60-90 cm. long, and tapers in the attachment region.  Sporophylls are pinnately arranged along the two sides of the flattened portion of the stipe.  The sporophylls are linear, approximately the same shape and size as the terminal blade; up to 20 occur on each side.

Habitat:  On rocks in the upper subtidal zone and down to a depth of about 5 fathoms.

Pacific Coast Distribution:  British Columbia to Mexico.

Reference:
Guide to Common Seaweeds of British Columbia, by R.F Scagel, Printed by K.M Macdonald,1972

pterpile

In the winter storms the woody Pterygophora stipes or stems often end up in drifts on the rocky beach. This photo was taken by G.Fletcher in February 2007.

pterostaranem

The stars on the stipe of Pterygophora were made by a sea urchin grazing. . Photo by Ryan Murphy

oct2011xsectptery

Annual rings in a cross-section of the stipe of Pterygophora : G Fletcher photo
taxonomyiconReturn to the Race Rocks Taxonomy and Image File
pearsonlogo2_f2The Race Rocks taxonomy is a collaborative venture originally started with the Biology and Environmental Systems students of Lester Pearson College UWC. It now also has contributions added by Faculty, Staff, Volunteers and Observers on the remote control webcams. -Ryan Murphy  PC yr 26

 

Pagurus hirsuitiusculus: hairy hermit crab–The Race Rocks Taxonomy

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This video shows the two species, the Hairy hermit crab Pagurus hirsuitiusculus and the sponge Suberites in a commensal biotic association.

hairy-pagurus

Hairy Hermit Crab: photo by Ryan Murphy

bandedantennae

A distinguishing feature of the hairy hermit crab is te banded antennae shown in this image from the video

The specimens studied were collected at  Race Rocks in November of 2002. They were unique specimens because of their choice of home. Usually hermit crabs use the shells of snails that have died then discard them as they grow larger in place of a bigger shell. However, these Hairy Hermit Crabs had decided to become the hermit crabs of Hermit Crab Sponges.

Hermit Crab Sponges, Suberites.spp are sponges that attach themselves to a mobile animal who has a solid exoskeleton, usually a snail or crab. In the hermit crab’s case, the sponge begins to grow on their adopted home by first thinly encrusting the shells. As the sponge grows, it begins to cover the shell and can surround it completely, sometimes making locomotion difficult for the crab. Once the sponge has buried the shell inside itself, the hermit crab leaves its shell to occupy a chamber in the sponge it had hollowed out.

CLASSIFICATION:
Domain: Eukarya
Kingdom: Animalia
Phylum: Arthropoda
Class: Crustacea
Order: Decapoda
Superfamily: Paguridea
Family: Paguridea
Genus: Pagurus
Species: hirsuitiusculus
Pagurus hirsuitiusculus
Common Name: Hairy Hermit Crab

Other Members of the Phylum Arthropoda at Race Rocks.

taxonomyiconReturn to the Race Rocks Taxonomy
and Image File
pearsonlogo2_f2The Race Rocks taxonomy is a collaborative venture originally started with the Biology and Environmental Systems students of Lester Pearson College UWC. It now also has contributions added by Faculty, Staff, Volunteers and Observers on the remote control webcams.

 

Ophlitaspongia pennata: velvety red sponge–The Race Rocks taxonomy

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The red sponge, Ophlitaspongia pennata and the nudibranch Rostanga sp. were found at a low tide in the late evening in November near the end of the docks, just beside the slipway at Race Rocks. These images are from the video below.

 

There are likely to be several types of encrusting red sponges growing in narrow crevices and on the undersides of overhanging ledges. Indeed, there are about ten intertidal species of red to orange encrusting sponges along the Pacific coast. Ophlitaspongia pennata is a beautifully coral-red form characterized, especially after drying, by starry oscula; its surface is velvety. De Laubenfels (1932) remarked that it occurs clear up to the half-tide mark (higher up than any other sponge), especially on vertical rocks under pendant seaweed, hence shaded from direct sunlight. Ophlitaspongia pennata is recorded from (Vancouver Island), British Columbia, to near Puertocitos, Baja California.

Domain Eukarya
Kingdom Animalia
Phylum Porifera
Class Demospongiae
Order Poecilosclerida
Family Clathriidae
Subclass Ceractinomorpha
Genus Ophlitaspongia
Species pennata
Common Name Velvety Red Sponge/ Red Midtide Sponge

This type of Red Sponge can be colored bright red to almost a dull orange-red. It has a smooth and tough surface. It has holes scattered around on it: the holes are about 2 millimeters wide. Its predators are nudibranchs, snails and seastars. They feed on shrimp, crabs and many other organisms.These tiny flat red to orange colored sponges encrust vertically on rocks shaded from sunlight.Biotic Associations: Often found with a predator, Rostanga pulchra

This file is provided as part of a collaborative effort by the students, faculty, staff and volunteers of Lester B. Pearson College February 2002 Sarah  MonsalveR.
Colombia PC Yr 28

Link to other sponge species from Race Rocks

Link to the Race Rocks Taxonomy and Image Gallery 

Mytilus californianus: California Mussel

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musshand2

Very old and large Mytilus californianus in the intertidal zone at Race Rocks. This is one of the advantages of long term preservation of the area as an Ecological Reserve.

The pea crab (as one can see in the picture), Fabia subquadrata is found in 1 to 3% of California mussels along the central California coast and 18% of mussels along Vancouver Island. This is a parasite that lives within the shell, because they rob food from their host and sometimes damage one of the gills. Public health codes usually prohibit the marketing or serving of parasitized animals but since the pea crab is very tasty, organisms with this crab are sometimes sold. Moreover, in a small portion of the population you can find imperfect pearls. These are of no value. http://www.lanecc.edu/science/zonation/mussel.htm (accessed 31 January 2002)

Morris, R., P. Abbott and E. Haderlie. 1980. Intertidal Invertebrates of California. Stanford University Press, Stanford, California. 690 pages.
Domain Eukarya
Kingdom Animalia
Phylum Mollusca
Class Bivalvia
Subclass Pteriomorpha
Order Mytiloida
Family Mytilidae
Genus Mytilus
Species californianus

Common Name: California mussel
Other Members of the Phylum Mollusca at Race Rocks.

taxonomyiconReturn to the Race Rocks Taxonomy
and Image File
pearsonlogo2_f2The Race Rocks taxonomy is a collaborative venture originally started with the Biology and Environmental Systems students of Lester Pearson College UWC. It now also has contributions added by Faculty, Staff, Volunteers and Observers on the remote control webcams.
Simon Michaud PC Yr. 28



Phyllolithodes papillosus: Heart Crab –The Race Rocks Taxonomy

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The Heart Crab – Phyllolithodes papillosusGeneral Description:

This very distinct crab is most commonly identified by the heart shaped markings on its back, hence his common name, the Heart Crab. This triangular carapace measures from 50X60mm (female) to 90X90mm (male), and is coloured a muddy greenish brown with dark red ridges. The claws, legs and carapace are covered in prickly spines, which helps to camouflage and as a defense mechanism. The Heart Crab has three pairs of walking legs coloured dark brown and a pair of chelipeds that are dark brown with turquoise bumps. Another distinction that is evident on the Heart Crab is the two blunt horns above his eyes and a large spine between them.
Domain Eukarya
Kingdom Animal
Phylum Arthropoda
Class Malacostraca
Order Decapoda
Family Lithodidae
Genus Phyllolithodes
Species papillosus
Common Name: Heart Crab
Habitat and Range:

The Heart Crab is rarely sighted in the open nor do they inhabit the intertidal zone, instead they prefer to live subtidally in a rocky habitat, hiding in crevices with moderate exposure and strong currents. They range along the Pacific coast of North America from Alaska to California inhabiting areas as deep as 183m.

Predators and Prey:

The main predator of the Heart Crab is the octopus, and the main prey of heart crabs are sponges and sea urchins, however they are observed eating other things in captivity.

Reproduction:

All mature female Heart Crabs undergo an obligate molt occuring in the spring, from March through May. At this time of molting female are held by the chelipeds of a male. After the molting is finished and the female’s exoskeleton has hardened, the couple copulate. During this a ribbon containing spermatophores is attached around the female. The fertilization occurs within hours, after this the male separates from the female. The female then incubates her eggs for almost twelve months. Eggs are layed in the late summer, August through September. Newly laid eggs are bright yellow, orange or dark red coloured which eventually dull to a muddy brown prior to hatching.

Biotic Association:

An interesting behavior observed of the Heart Crab is the form of symbiosis,commensalism, the association between two organisms when one organism benefits and the other is neither harmed nor benefited. After molting, the Heart Crab takes shelter under the tentacle canopy of the snakelock anemone, as he is not harmed by this and the crab is protected,
References:Accessed Jan.25, 2001

http://oceanlink.island.net/oinfo/biodiversity/heartcrab.html

http://www3.bc.sypatico.ca/kerryw/creature/heart.htm

http://www.afsc.noaa.gov/kodiak/photo/triangle.htm

 

Other Members of the Phylum Arthropoda at Race Rocks 
taxonomyiconReturn to the Race Rocks Taxonomy
and Image File
pearsonlogo2_f2The Race Rocks taxonomy is a collaborative venture originally started with the Biology and Environmental Systems students of Lester Pearson College UWC. It now also has contributions added by Faculty, Staff, Volunteers and Observers on the remote control webcams.

Cait Caines–year 28(PC)