Category Archives: Invertebrate

Neomolgus littoralis: the red velvet mite

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The video above was taken by Peg 15 on the North Shore of Great Race Rock where the students of a biology class were doing an intertidal transect. We often find Neomolgus at this elevation, and it is one of the few invertebrates inhabiting the top range of the spray zone.

Neomolgus is a tiny mite looking like a little red dot moving across rocks or other hard surfaces. Its diameter is 3mm. Mites are like spiders and ticks in that they have four pairs of legs. At Race Rocks, it is especially common among the bare rocks out on the North West corner by peg15.

Neomolgus has a large distribution in the northern hemisphere. It moves very actively and responds very negatively to the approach of a human finger. It uses its long snout for piercing small flies and sucking their juices.

Links:http://www.beachwatchers.wsu.edu/ezidweb/neomol01.htm

Kozlof : SeashoreLife of the Northern Pacific Coast.

Lamb and Hanby, Marine Life of the Pacific Northwest, page 276

Domain Eukarya
Kingdom Animalia
Phylum Arthropoda
Class arachnida
Order Acari
Trombidiformes
Family Bdellidae
Genus Neomolgus
Species littoralis
Common Name:red velvet mite

 

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.

 March October 2003-  Rahilla (PC)

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

Arctonoe vittata: Commensal scale worm–The Race Rocks Taxonomy

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scaleworm

Scaleworm on the striped sunstar.( from video)

Physical description: 

The Arctonoe vittata (formerly known as Halosydna lordi) usually have around 25 or more pairs of scale, which they sometimes shed when they are disturbed. Arctonoe grows up to 8cm to 10 cm long and is usually light yellow. However the color may change depending on its host. Scientists do not know wether this is due to a certain compound on the host that changes their color, or wether it is because they basically eat the same thing, but the scale worm usually very lightly changes its color according to its host.

Distribution in the world: Scale worms live in the North Pacific ocean. It is one of the most studied worms and it has been mostly studied near the coasts of Japan and also near Kamtchaka, far east Russia. It also lives in the north west coast of North America, including the coast of British Columbia. It lives mostly in salt water and almost never in fresh water.

Biotic Associations: The Arctonoe vittata a commensal worm, lives on other species. It observes a positive relationship with its host, notably the starfish Asterias amurensis or the mollusc keyhole limpet Diadora aspera It usually lives near the oral part of its host, and when there are two A.vittata there, the other one will live on the arm if it is living on a starfish. The length of the worm is big considering the size of its host, sometimes its ends almost touch when it is curled up on the oral orifice. It mostly likes to live on larger hosts because they are older and more exposed to plankton. If the A.vittata is living on the keyhole limpet, and the keyhole gets attacked by a starfish, the worm will sense that the demise of its host will lead to its own demise. Thus it will bite the seastar’s tube feet and cause it to withdraw. The scale worm is attracted to chemicals released by it’s host. It is interesting to note that the host is also attracted by chemicals released by the commensal worm. The commensal worms seemed to have a different taste for their host depending on which part of the world they came from. However, the limpet Acmaea pallida was the overall favorite host.

Interesting local behavior: Some scale worms have been spotted on seastars. They were colored white, the same as the underside of the star. There have also been some scale worms spotted on sea cucumbers, they were of a reddish color, and were the Red commensal scale worm Arctonoe pulchra

Reproduction and feeding: The A.vittata bites off the food that is left over from the side of the mouth of its host. They are usually fatter if they are located near the mouth of the host. The worms are hermaphrodites. The worm will leave eggs on its host, some grow there, usually the first ones. The rest will move to a different host because there is too much competition with the one that is already there.

Domain Eukarya
Kingdom Animalia
Phylum Annelida
Class Polychaeta
Order polychaetes
Family polynoidae
Genus Arctonoe
Species vittata

Other Annelids 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.  Oct 2003, Lindsay Cheong

with underwater photography of Ryan Murphy

Notoplana acticola: flatworm– The Race Rocks taxonomy

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Notoplana acticola is a polyclad flatworm and it is one of the common polyclads of rocky shores. A specimen may be more than 2cm in length, but the average is about 1cm. We find these occasionally in the mussel beds and under rocks in the lower intertidal.

notoplanaacticola

Some mature Notoplana acticola are sometimes found as hermaphrodites.

Notoplana acticola lives in the upper tide pools and it may be abundant in the lower tide pools as well.

Domain Eukarya
Kingdom animalia
Phylum platyhelminthes
Class turbellaria
Order polycladida
Family otocelid
Genus notoplana
Species  acticola
Common Name:  flatworm
This file is provided as part of a collaborative effort by the students, faculty, staff, and volunteers  of
Lester B. Pearson College
Oct 19, 2003		 Aline Celine

Fabia subquadrata: The Pea Crab — The Race Rocks Taxonomy

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Jeremias, Carmen and Felix remove a pea crab from the mantle of a California Mussel.
At Race Rocks there are many large mussels; (up to 30 cm) with such parasite inside.

 

Domain Eukarya
Kingdom Animalia
Phylum Arthropoda
Class Crustacea
Order Decapoda
Family Pinnotheridae
Genus Fabia
Species subquadrata
Common Name:Pea crab

Brief Definition

Pea/Mussel crabs are tiny creatures that live as symbionts, on or in the bodies of other invertebrates (bivalves)

Size

As their common name implies, Pea crabs are small creatures. The female pea crabs are distinctively larger than the male crabs, reachimg a size of 22mm (0.8in). The males however reach a size of 7.3mm (0.3in).

Habitat

Pea crabs occupy 2 different niches during their lifetime. Prior to and after their mating season, the adult female lives in a host. Host species include:

California mussels ( Mytilus californianus )

horse mussels ( Modiolus modiolus ).

Mytilus edulis

As well as other species of bivalves including scallops, oysters, cockles and clams.

The juvenile crabs also occupy a host before they become mature.

Range

These crabs live in mainly the northern hemisphere waters.

Including eastern and western U.S.(Akutan Pass, in the waters of Alaska to Ensenada.), Europe, Argentina and British Columbia, Canada.

It is found in 1 to 3% of California mussels along the central California coast, and 18% of mussels along Vancouver Island, BC, Canada.

Adaptation

Mussel crabs live in specific hosts because each crab responds positively to only certain chemicals that their hosts emit. In this way, they are able to infest the hosts that have the right conditions for them to survive. While in the host, these crabs do not posses an exokeleton. This is beacause the hosts provide them with protection against predators and other harmful external factors. However, when they leave their host to mate in the planktonic environment, the adult crabs grow an exoskeleton to protect their membranous carapace. These crabs also posses 10 legs, of which 2 of them develop into large and powerful claws to help fend off predators when exposed in the plankton, and to also help in the grasping of food.

Relationship with Host

The relationship that exists between the mussel crab and the bivalve is a symbiotic one. The advantage of this relationship is that the crab is protected while it scavenges the necessary nutrients needed by it, in the host. The crab however at times robs its host of a large mount of food and it also feeds off the protective mucus layers that cover the host’s tender tissues.This results in the mussel’s gills been injured. When this occurs the relationship becomes a parasitic one as the crab benefits while the host is affected negatively. Hence they are classified as parasites.

Precautions are taken when animals such as Mya arenaria, Placopecten magellanicus, Argopecten irradians and oysters are sold as to not have a pea crab inside it.

Reproduction and Lifecycle

The pea crabs’ life cycle has two distinct stages. These two stages are so different that in fact they were classified into two different genera.

The first stage comprises of the large, adult females that have soft membranous crapaces. These adults occupy a host each and they produce larvae that mature into the second stage. In the second stage, the offspring (larvae) of the female (that she had produced inside her host) grow up into adults of both sexes.Having reached maturity, they leave their hosts and join swarms in the water to mate. At this stage the pea crabs look more ‘traditional’. They have hard shells, strong legs (for swimming) and at the front of the carapace they have thick hair. Upon completion of mating, the female returns to her host. For a period of 21-25 weeks, she goes through 5 molts before reaching maturity. The female can inhabit here for up to a year, producing larvae from eggs that where fertilised by sperm from her single mating and then the cycle begins again. The mating takes place in late May.

Note: the male after mating dies.

References

Source 1: Pacific Coast Crabs and Shrimps by Gregory.C. Jensen, Ph.D

Source 2: Port Townsend Marine Science Center. Marine & Natural History Exihibits

Source 3: http://www.ptmsc.org/html/peacrabs.html

Source 4: http://life.bio.sunysb.edu/~jmatth/Science.htm

Source 5: http://www.pac.dfo-mpo.gc.ca/sci/shelldis/pages/pcbmu_e.htm

Source 6: http://www.indian-ocean.org/bioinformatics/crabs/crabs/tex1.html

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.

October 2003-  Michelle(PC)

Ecological Equivalents Galapagos Islands vs. Race Rocks

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BACKGROUND: As you encounter different ecosystems representing a wide range of ecological niches in different parts of the world, you will begin to notice that there are many examples of organisms which may not even be related which play the same role in the ecosystems of widely separated geographic areas. I came across several examples which may be considered “ecological equivalents” while spending a week aboard the vessel “Samba” in the Galapagos Islands in June 2003. Although separated by 47 degrees of latitude and thousands of miles, surprisingly there are several examples of ecological equivalents on the island archipelagos of Race Rocks and the Galapagos. Islands.

DEFINITION.…Ecological equivalents : species that use similar niches in different habitats or locations are called ecological equivalents .The evolution of life has resulted in general types of habitats and certain successful ways of exploiting the resources in those habitats. Parallel evolution has resulted in unrelated species that have similar niches in different environments.

ECOLOGICAL EQUIVALENTS : GALAPAGOS ISLANDS VS. RACE ROCKS

 

 

Tigriopus californicus: Harpacticoid–The Race Rocks Taxonomy

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We frequently find abundant populations of Harpacticoids in the high tidepools number 10, 7 and 2 at Race Rocks

Populations can fluctuate widely through the seasons.. Since pool 7 is at the highest elevation, it may not receive new inputs of seawater unless there is a wind from the West. In the summer, with no rain, and with elevated temperatures, this shallow pool will develop salt crystals. At that time, the only population of Tigriopus californicus is in pool 2 which is deeper and shaded, and in pool 10 which is small but shaded. Later on, in October, pool 7 may have an abundant population concentrated along the vertical walls of the pool. In this photo, The photo above was taken on a compound microscope at 10 power, but it has been enlarged considerably by photomicrography

In this photo Gerald has scooped up a sample from pool 10,where they are visible to the naked eye as small moving reddish dots.

 

 

 

Research done on this organism by the student T.C. Merchant at the Hopkins Marine Station of Stanford University in 1977, refers to this unique osmoregulatory adaptation for this Euryhaline environment.

“Abstract: Tigriopus californicus exhibit a unique osmoregulatory behavior which is highly adaptive in the high splash pool habitat. They conform osmotically in intermediate salinities and regulate hypo and hyper osmotically in high and low salinities respectively. Gut fluid appears to remain isosmotic with the environment. Evidence is presented to suggest the gut may be a regulatory surface in Tigriopus. The range of osmoconformance depends on the length of acclimation to a given salinity. O2 consumption in Tigriopus is high in low salinities decreasing as salinity rises. Metabolism appears not to change significantly over the conforming range 35 to 60 0/00″

Other interesting research on this organism has been on its Phylogeny. Research done in southern latitudes on Tigriopus revealed one of the highest levels of mitochondrial DNA differentiation ever reported among conspecific populations. S.Edmands ( Molecular Ecology,Volume 10 Page 1743  – July 2001) showed that populations from Puget Sound northward had significantly reduced levels of within-population variation based on cytochrome oxidase I sequences. These patterns are hypothesized to result from the contraction and expansion of populations driven by recent ice ages.

The Pesticide Action Network North America.lists extensive results of toxicity studies with Pesticides using Tigriopus californicus.

Dr. Maarten Voordouw working with Dr.Brad Anholt of the University of Victoria has researched the evolution of Sex ratios in Tigriopus californicus. He found there to be a variation in offspring sex ratio larger than the binomial expectation, and that females produce male-biased clutches at higher temperatures. The trait is heritable and is transmitted primarily through the paternal line. http://web.uvic.ca/~banholt/anhlabsite/tigs.html

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.   G.Fletcher

 

The Giant Pacific Octopus

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Giant PacificOctopus frequently appear at Race Rocks in the subtidal waters. They are also seen occasionally washed up in the intertidal zone where they contribute to the energy flow of the gulls and eagles. This individual which had died recentlyin June 2002, became the subject of a webcast and an impromptu dissection on the shore.

 

Ceramaster arcticus: The Race Rocks Taxonomy

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Our thanks to The Royal British Columbia Museum for providing this photo taken by Brent Cooke.

 

Domain Eukarya
Kingdom Animalia
Phylum Echinodermata
Class Asteroidea
Family Goniasteridae
Genus Ceremaster
Species arcticus (Verrill 1909)
Common Name:
Ceramaster arcticus (Verrill 1909) (Goniasteridae)

 

From the information Phil Lambert submitted to  Syesis, 11:61–64 (1978)

Ceramaster arcticus (Verrill 1909) (Goniasteridae)
British Columbia: Race Rocks, Victoria, 9 m, one specimen (BCPM 973-251-34);

Winter Inlet, Pearse Island, 23 rn, one specimen (BCPM 974-224-43);
Work Channel, 31 m, two specimens (BCPM 974391-6);
northwest of Queen Charlotte Islands, 119 m, one specimen (NMC 1733).

Previously known from Bering Sea to St. Paul Harbour, Kodiak Island, Alaska (57*461N, 152*27W) (Fisher 1911), littoral zone to 186 rn (D’yakonov 1950). The specimen from Race Rocks (48*18’N, 123,36’W) extends the known range 2180 km southward.

References :
Philip Lambert, New geographic and bathymetric records for some northeast Pacific asteroids (Echinodermata: Asteroidea) Syesis, 11:61–64 (1978)

Royal British Columbia Museum Collection data. 

Catalogue Number: 973-00251-034
Collector’s Field Number:
Scientific Name: Ceramaster arcticus

Collection Event

Collection Date(YYYY-MM-DD): 1973-09-18

Geographic Place

Location Name: Victoria; Race Rocks
Location Description: passage between lighthouse and small islets in the lee of the rock
Province/State: British Columbia
Other Members of the Phylum Echinodermata 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

Oregonia gracilis: Decorator Crab — The Race Rocks Taxonomy

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Decorator crabs are common in the intertidal and subtidal areas at Race Rocs. Their habit of attaching bits of algae, or shell on their carapace makes them well camouflaged. They are a small crab, only up to 2-3 cm width in their carapace. 

In 1889, William Bateson observed in detail the way that decorator crabs fix materials on their backs. He noted that “[t]he whole proceeding is most human and purposeful”, and that if a Stenorhynchus crab is cleaned, it will “immediately begin to clothe itself again with the same care and precision as before”.[2](Wikipedia)
Domain Eukarya
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Crustacea
Class: Malacostrata
Order: Decapoda
Family: Majidae
Genus Oregonia
Species gracilis
Common Name: Decorator 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.

 name 2002 (PC)