Category Archives: Invertebrate

Isodictya rigida: finger sponge– Race Rocks Taxonomy

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isodictya

This image, taken by Russel Wyeth,assistant to Dr. Gitai Yahel  off the docks at Race Rocks, shows the intricate associations of other invertebrates sharing the same habitat.

juancarlosponge

Juan Carlos took these images while doing a video of the path for the tidal generator cable.

The biodiversity in locations which receive heavy current is considerable. Depth 12 meters.

Kingdom: Animalia Phylum: Porifera Class: Demospongiae Order: Poecilosclerida Suborder: Mycalina Family: Isodictyidae Genus: Isodictya Bowerbank, 1864 Species: rigida ( Lambe, 1893)

This file is provided as part of a collaborative effort by the students, faculty,volunteers,staff and researchers of Lester B. Pearson College
 Date: 2005 Dr. Gitai Yahel

Escape Response of California Sea Cucumber

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Parastichopus californicus escapes predation by the sunflower seastar Pycnopodia helianthoides. By releasing itself on the approach of the seastar the Parastichopus can be carried away by the current.  Also shown are the escape responses of sea urchins and topshells.

California Sea cucumber reproduction

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This California Sea Cucumber male was emitting sperm while in the tank at Race Rocks in early June, 2004 . This went on for several hours. Millions of sperm are broadcast into the water where they may have a chance encounter with eggs, also released into the current by the females. Of the great numbers of eggs and sperm released only a few are fertilized and actually make it to maturity. This is a good example of
r-selection in the population.

The Johan Ashuvud 2004 project

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n the first week of June 2004, four students and two researchers stayed at Race Rocks for an intensive week. Sponsorship for this week comes from the Johan Ashuvud memorial fund. Webcasts of the day’s events took place every night and on two days, school groups came out to help produce a program for live webcasting.

(https://www.racerocks.ca/johan-ashuvud-project-at-race-rocks-2004/)

 

During the Johan Ashuvud project 2004, students explored the intertidal with Garry Fletcher. They examined various organisms as well as the artificial tidepool. In this video, we also get a chance to meet all the students taking part in the project.

 

Gammarus sp. : Scud–The Race Rocks taxonomy

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From Wikkipedias: Gammarus is an amphipod crustacean genus in the family Gammaridae. It contains more than 200 described species, making it one of the most speciose genera of crustaceans.[2] Different species have different optimal conditions, particularly in terms of salinity, and different tolerances; Gammarus pulex, for instance, is a purely freshwater species, while Gammarus locusta is estuarine, only living where the salinity is greater than 25‰.[3] Species of Gammarus are the typical “scuds” of North America and range widely throughout the Holarctic. A considerable number are also found southwards into the Northern Hemisphere tropics, particularly in Southeast Asia.[4]
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Crustacea
Class: Malacostraca
Order: Amphipoda
Suborder: Senticaudata
Family: Gammaridae
Genus: Gammarus Fabricius, 1775
Type species
Gammarus pulex Linnaeus, 1758 [1]
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.

Mopalia mucosa: Mossy chiton

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chitonmossy-1

Mopalia mucosa Mossy Chiton

Size: Can range between 5 cm to 9 cm in width.

Description: Oval shaped and low and dome shaped shell. It is covered by small interlacing plates which are covered by stiff mossy dark brown hairs. The inside of the shells are of a turquoise colour. Chitons have a broad flat foot” which it uses to move and to stick to its rocky homes.

Habitat: They are usually found on rocks and in tidepools located in the middle to low intertidal zones where they are protected from heavy wave action. They can be found from the Queen Charlotte Islands in British Columbia down to California.


Diet: Red or Green algae

Activity: They can usually be found clinging to rocks. If they are somehow displaced from these, they roll into balls in order to protect their soft insides. Their foot can secrete small amounts of mucous which, along with muscular contractions, allows it to move. However, it prefers to move as little as possible and will only do so at night and when it is covered by water.

Predators: Mostly glaucous-winged gulls and black oystercatchers

Websites Consulted:
http://www.manandmollusc.net/advanced_introduction/moll101polyplacophora.html [Sep 22, 05]
http://faculty.northseattle.edu/ecauldwell/bio125/intertidal_lecture4.htm [Sep 22, 05]

http://66.102.7.104/search?q=cache:SUFBplz0MToJ:www.dohenystatebeach.org/pdffiles/tdplpack.pdf
+Mossy+Chiton+predators&hl=en [AccessedSep 22, 05]Other Members of the Class Aves 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. Original by Raisa Mirza, 2004

 

 

In Situ Measurement of Benthic Community Trophic Dynamics at Race Rocks

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Research of GITAI YAHEL

In March, 2004, Dr.Gitai Yahel, a Post Doctorate researcher from the Biology Department at the University of Victoria, joined us for two dives at Race Rocks to check out the possibility of doing research there. He is interested in suspension feeders’ nutritional ecology and the role of dissolved substance as a food source for marine organisms. Currently he is trying to establish a field survey of the dissolved and picoplanktonic diet composition of active suspension feeders such as sponge, mussels and tunicates.

Sponges, bivalves and tunicates play an important role in the trophic dynamics of many benthic communities. However, direct in situ measurements of their diet composition, filtration and excretion rates are lacking. Our knowledge of these rates is based mostly on indirect, in vitro measurements. Recently we have developed an in situ, non-intrusive technique to directly measure the rate and efficiency by which an active suspension feeder removes (or discharges) substances from (to) the water it filters. The technique, termed “InEx”, is based on the simultaneous, pair-wise collection of the water Inhaled and Exhaled by the animal. The difference in the concentrations of a substance among a pair of samples provides a measure of the retention (or excretion) of the substance by the animal. Calculations of feeding (or excretion) rates are obtained by multiplying the concentration difference by pumping rate. The latter is concurrently measured by recording the movement of a dye front in a transparent tube positioned within the ex-current jet. An important quality of the InEx technique is the lack of any manipulation of the studied organisms thus allowing realistic estimates of the organism’s performance under natural conditions. Former work in tropical water had revealed novel aspects of suspension feeders’ nutritional ecology including the major role dissolved organic substances play in the diet of some reef sponges (Yahel et al. 2003, Limnology and Oceanography, 48, 141).
For the proposed work at Race Rocks we can foresee two phases:

I. Identifying target suspension feeding taxa
We will execute a field survey of common suspension feeders at Race Rocks. Targets groups include bivalves, ascidians, and sponges. SCUBA divers will sample the water inhaled and exhaled by the surveyed organisms to compare concentration changes of CDOM, DOC, bacteria, phytoplankton, other organic particles, plant nutrients, silica, and sediment grains. Sampling methods will include an Inherent Optical Properties sensor (IOP, providing both CDOM spectra, concentration and optical characterization of the particulate field), Laser In Situ Scattering instrument (LISST, providing measurements of particles concentration and size distribution), and discrete water samples (InEx). The discrete water samples will be analyzed using a high temperature total carbon analyzer, flow injection nutrient analyzer, and a flow cytometer. This sampling scheme will provide ‘snapshot’ information on the performance of individual organisms.

II. Continuous monitoring of individual ‘model’ organisms.
Longer term (hours to days) monitoring of organisms will provide a record of feeding and metabolic performance with respect to environmental parameters (e.g., current, light, ambient particles concentration, etc.). Our knowledge of such processes in the field is limited. Nevertheless, the few existing studies suggest that suspension feeder activity may undergo considerable diel shifts. Moreover, environmental variables such as food and sediment concentration are known to affect suspension feeder filtration rates. Multi-day instrumentation of individual suspension feeders will provide a continuous record of the material fluxes mediated by the animals. Two 16 MHz ADVs’ (Acoustical Doppler Velocimeters) will provide high frequency (~2 Hz) current and acoustical backscatter data. One ADV will sample the exhalant jet of the study animal while the other will sample the inhalant (ambient) water. Similarly, paired measurements of optical water properties will be obtained by slowly pumping small amounts waters through a 4 sensor array mounted on a nearby frame. The instrument array will include: LISST-100, IOP sensors (WetLabs ac-9, and Eco-VSF,) CTD, and a Seabird oxygen sensor. The latter will allow us to estimate respiration rate and to correlate it to measured material fluxes mediated by the studied organisms. An online video camera equipped with an infra-red light source will be used to monitor the immediate vicinity of the exhalant aperture to allow better interpretation of behavior related signals (e.g. the presence of predators or sediment resuspension events).

Target organisms will be carefully selected based on the results of the survey in phase I. A priori, plausible candidates for these experiments are sponges and large bivalves (e.g. Mytilus californicus). These animals possess a large ex-current aperture that allows easy instrumentation and previous studies suggest that they may be capable of removing large quantities of DOC from the water.

Note that the proposed work in absolutely non destructive and the studied animals will not be manipulated by any means.

 

SEE ALSO https://www.racerocks.ca/journey-middle-school-students-visit-race-rocks/
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Hemigrapsus nudus-Purple Shore Crab– The Race Rocks Taxonomy

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At the mid-intertidal rocky shore level on southern Vancouver Island, you will frequently find this as the most common species of shorecrab. At Race Rocks, they particularly like the loose rock habitat of the intertidal area beside the boat ramp on the jetty. The maximum size this crab attains is that shown in the video, about a 2cm. width of carapace. Thanks to Taarini Chopra and the environmental systems class for this video done as part of a study on biotic associations of the invertebrates at Race Rocks. This species is a particularly good example because of the parasites it often carries


Domain Eukarya
Kingdom Animalia
Phylum Arthropoda
Class Malacostraca
Order Decapoda
Suborder Pleocymata
Family Grapsidae
Genus Hemigrapsus
Species nudus
Common Name: Purple shore 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.

March October 2003- Taarini Chopra (PC yr 27)

Serpula vermicularis: Calcareous tubeworm– The Race Rocks taxonomy

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This patch of calcareous-tubed serpulid worms is exposed on the north east corner of Great Race Rock in a crevasse at low tide. Many other invertebrate species are associated with it in this picture.

Domain Eukarya
Kingdom Animalia
Phylum Annelida
Class Polychaeta
Order Sabellida
Family Serpulidae
Subfamily Serpulinae
Genus Serpula
Species vermicularis
Linnaeus,1767
Common Name: Calcareous tubeworm

Description

Serpula vermicularis is a slender, tube-dwelling polychaete between 5 and 7 cm length with about 200 segments. The tubes are cylindrical with occasional rings and irregular lengthwise ridges cut into blunt teeth. The operculum is calcareous and funnel shaped with radial grooves and a serrated circumference.

The color of the body of the worm varies from pale yellow to brick red. The tube is pinkish-white and the operculum is patterned with red and white rays.

Size: up to 7cm

Growth form: vermiform segmented

 

Distribution

These are common at Race Rocks in the subtidal area. They are often seen by divers as small bright red spots which seem to disappear when approached. Their gills withdraw rapidly into the white calcareous tube.

These worms are commonly found throughout north-west and south-west coasts of England and are distributed in the north-east Atlantic and the Mediterranean.

Physiographic preferences: open coast, offshore seabed, estuary

Habit info

The calcareous tubes of Serpula vermicularis can be found attached to hard substrates such as rocks, stones, bivalve shells and ship hulls from low water to the sublittoral in depths up to 250 m. In some very sheltered areas the tubes aggregate together to form small reefs. Often a mass of coiled white tubes shows up on the shore after a storm attached to the holdfasts of kelp .

Reproduction

Type: Gonochoristic

Frequency: annual episodic

Development mechanism: Planktotrophic

Life span: 2-5 years

 An interesting feeding method, kleptoparasitism, of the larva is documented inresearch:

Other Members of the Phylum Annelida 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-  Martina Naschberger (PC)

Martina Naschberger

 

Cryptolithodes sitchensis: turtle crab –The Race Rocks taxonomy

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turtle crab (Cryptolithodes sitchensis). Photos b y Laura Verhegge 

 

Appearance: Cryptolithodes sitchensis range from bright red or orange to gray and even white colors. The average size of an adult turtle crab is 90mm (3.6in). A distinctive characteristic of the crab is that its legs are completely covered by its shell.

Distribution: The turtle crab can be found from Sitka, Alaska along the coast to Point Lowa, California,
Domain Eukarya
Kingdom Animalia
Phylum: Arthropoda
Subphylum Crustacea
Class Malacostraca
Order Decapoda
Suborder: Pleocyemata
Family: Lithodidae
Superfamily: Paguroidea
Genus Cryptolithodes
Species sitchensis
Common Name:Turtle Crab or Umbrella Crab

Where at Race Rocks? This species can be found at Race Rocks and on Rosedale Reef. In the summer of 1997, Donna Gibbs had noted specimens of Cryptolithodes sitchensis. in her inventory.

Habitat: This particular type of crab is usually found on bedrock from the low intertidal zone to 17m (56ft), in semi-protected area on or near the outer coast. Furthermore, the turtle crab rarely leaves its home.

Feeding: While on bedrock, the turtle crab grazes and feeds on sessile organisms, particularly algae.

Reproduction: The turtle crab reproduces sexually, using the molting cycle. There are six stages in the development of the turtle crab: Eggs, Prezoea, Zoea, Megalops, Juvenile Instar, Adult Crab.

Interesting Adaptation: Its distinctive shell allows it to camouflage itself into its surroundings. It is often mistaken for an old clam shell or patch or coralline algae.

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.

AJ (PC year30)