Daily Archives: Saturday,December 15, 2001

Codium fragile : Green sea fingers–The Race Rocks Taxonomy

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cfragile2

Codium fragile and several red algae species  in the background–  photo Ryan Murphy

Habitats of Codium fragile:

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Codium fragile hanging from the rock on the south side of the south penninsula. –2002 photo G.Fletcher

Codium fragile is native to the Pacific Ocean. The species inhabits the middle and lower intertidal zone as well as subtidal regions of rocky shores.t is also found in large tide pools permanently filled with water. Therefore it is found at Race Rocks. At Race Rocks in 2001, the species occurred in only two small areas, although it was found when diving in earlier years in larger beds, shallow subtidally on the south side of Bentinck Island just across Race Passage north from Race Rocks. On the north side of the Great Race, there was one plant in a tide pool, and on the South East side, several dozen plants have occurred since the early 1980’s along the zero tide level of the small peninsula island. In 2004 it has been observed in several tidepools however its population still remains limited.

Structure of Codium fragile:

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Codium fragile on underside of rock– photo by Ryan Murphy

Codium fragile is a dark green alga, ranging from ten to 40 cm high and consists of repeatedly branching cylindrical segments about 0.5 to 1.0 cm in diameter, and the branches can be as thick as pencil. The segments look like dark green fingers. Its holdfast is a broad, sponge like cushion of tissue. The tips of segments are blunt and the surface is soft, so it is sometimes mistaken as a sponge. Its body consists of interwoven, filamentous cells with incomplete crosswalls forming the inner part of the branches.

Invasive species note: There is another subspecies, Tomentosoides (van Goor) Silva, which is harmful in shellfish beds in the Atlantic. It grows to a much longer length.

Links and References:

1. Common Seaweeds of the Pacific Coast, J. Robert Waaland, Pacific Search Press.

2. Seashore Life of the Northern Pacific Coast, Eugene N. Kozloff, 1973/1983 University of Washington Press.

Classification:
Domain: Eukarya
Kingdom: Protoctista
Phylum: Chlorophyta (Green Algae)
Class: Chlorophyceae
Order: Codiales
Family: Codiaceae
Genus: Codium
Species: fragile (Suringar) Heriot
COMMON NAME: Green sea fingers

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.
Dec 2001–Philip Kam PC-yr.27

 

Anthopleura elegantissima: Aggregating Anemone-Race Rocks taxonomy

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Anthopleura growing in a moist crevasse. Photo by Ryan Murphy.

One of the many organisms found at Race Rocks are sea anemones. Sea anemones belong to the phylum known as the Cnidaria, from the cnida or stinging cells that are present in this major group of animals that also include corals, jellyfish, hydroids, medusae, and sea fans. Sea anemones, corals and their allies form the class know as the Anthozoa. Anthopleura elegantissima is abundant on rock faces or boulders, in tide pools or crevices, on wharf pilings, singly or in dense aggregations (Smith and Carlton, 1975)

 

 

 

 

 

anthopleur       Link to extended essay of Santiago on Anthopleura distribution in the intertidal zone.

 

 

 

 

maliha   Link to  the extended essay by Maliha Zahid on Anthopleura-elegantissima-Distribution

 

 

 

 

Kingdom Animalia
Phylum Cnidaria
Class Anthozoa
Subclass Zoantharia
Order Actiniatia
Family Actiniidae
Genus Anthopleura
Species elegantissima
Common Name Aggregating Anemone

 

Characteristics:

  • The aggregating anenome is 2-5 cm in column diameter and 4-5 cm high in its clonal form.
  • The tentacular crown is roughly 8 centimeters in diameter.
  • The species presents numerous short tentacles, in five or more cycles, which are variously colored.
  • At the bases of its tentacles are bulbous structures where certain types of stinging capsules are concentrated.
  • The column is light green to white, and twice as long as wide when extended, with longitudinal rows of adhesive tubercles (verrucae)
  • Rock, sand, and shell fragments accumulate on anenome by adhering to the tubercles on the column.
  • The anenome is a green or olive colour depending on the algae living in its tissues.

Habitat:

It is a species characteristic of middle intertidal zone of semi protected rocky shores of both bays and outer coast from Alaska to Baja California.

Reproduction:

Anthopleura elegantissima reproduces both sexually and asexually. In sexual reproduction, ova are present as early as February and grow steadily until their release in July; the ovarian is then resorbed and new eggs do not appear until the following February. Sperm are released through the summer. The asexual reproduction occurs by longitudinal fission. This process results in aggregations or clones of anemones pressed together in concentrations of several hundred per square meter.

Ecological Niche:

  • Anthopleura elegantissima is a carnivore, feeding on small crustacians such as copepods, isopods, amphipods, and other small animals that contact the tentacles.
  • It is preyed upon by the nudibranch Aeolidia papillosa, which usually attacks the column, by the nail Epitonium tinctum, which attacks the tips of the tentacles, and by sea stars such as Dermasterias imbricata that can engulf an entire small anemone.
  • Moreover, in some anemones, small pink amphipods, Allogaussia recondita, make a home in the gastro vascular cavity. Two types of unicellular algae live in the tissues ofAnthopleura elegantissima in a symbiotic relationship. It is these algae that give the anenome its distinctive green or olive colour.

Interesting Further Studies:

  • Ecological niche study was conducted by Santiago, Pearson College Student 1998-2000../../research/santiago/santiago.htm
  • The US Environmental Protection Agency (EPA) has investigated using aggregating anenome as a test for salinity. This bioindicator would be used to see the freshwater influx in ocean environments. http://es.epa.gov/ncer/fellow/progress/99/cohenri00.html
  • The behaviour of Anthopleura elegantissima at different depths.
  • The reproduction cycle of Anthopleura elegantissima.
  • Further study of aggregating anenomes at Race Rocks.

References:

  • Kozloff, Eugene N. Seashore Life of the Northern Pacific Coast. (Seattle: University of Washington Press, 1983).
  • Kozloff, Eugene N. Keys to the Marine Invertebrates of Puget Sound, the San Juan Archipelago, and Adjacent Regions. (Seattle: University of Washington Press, 1974).
  • Morris, R.H. etal. Intertidal Invertebrates of California. (Stanford: Stanford University Press, 1980).

 

Sea lions growling again

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Saturday, December 15, 2001
Good Evening
TEMPERATURE: Max. 7.0C — Min. 4.7C — Reset 6.9C — Rain 1.4 mm
posted by Carol or Mike S at 6:08 PM
WEATHER: light winds all day,a nice break from the roaring westerly. It was nice to be able to hear the sea lions growling and barking again. Looks like we may be in for another stormy night judging from the swell that is starting to come in from the south east.Some of the Sea Lions on the east ridge are jumping into the water as the 3-4metre waves break over them while others are moving down the west side of the ridge to join a group of 14 California sea lions and the 2 Elephant Seals that have been hauled out all day.The Harbour seals are hauling out as the tide ebbs and unless disturbed will stay ‘high and dry’ until the tide comes in again.
–Today is the first day we have seen the large male elephant seal back on middle rock – ( see camera1- note added by Garry)
posted by Carol or Mike S at 4:37 PM

Good Morning

WEATHER: Sky Overcast — Vis. 15 Miles — Wind North East 9 Knots — Sea Rippled
posted by Carol or Mike S at 7:26 AM

Hexagrammos decagrammus : Kelp Greenling –The Race Rocks Taxonomy

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Kelp Greenling (Hexagrammas decagrammus) are one of the most abundant bottom or demersal fish in the shallow benthic community at Race Rocks.


All demersal fish such as this are protected in the  ecological reserve with the Rockfish Protection zone.
Domain Eukarya
Kingdom Animalia
Phylum Chordata
Subphylum Vertebrata
Class Actinopterygii
Order Scorpaeniformes
Family Hexagrammidae
Subfamily Hexagramminae
Genus Hexagrammos
Species decagrammus
COMMON NAME: greenling sea trout; speckled sea trout; tommy cod
The Kelp Greenling is one of the few fish that has 5 lateral lines on each side. Males and females are sexually dimorphic, the females being a distinct orange color, while the males are bluish in color. Females are profusely covered with orange-reddish spots. Males are brown or gray in colour with a few blue spots on the front part of their body. Each of these spots is surrounded by a ring of reddish brown. We frequently see these fish dodging in under the canopy of the brown algae Pterophyga.

male kelp greenling

The Kelp Greenling is a rocky reef fish, found on the bottom of the ocean, often in dense macroalgae.They are abundant all along the front cliff off the docks at Race Rocks.

female kelp greenling

Between Alaska and Central California, most of them live from lower intertidal waters to about 50 feet, with females tending to live in shallower water than males.

The typical Kelp Greenling is about ten inches long, but the largest in record was 21 inches.

female kelp greenling

Females grow faster than males. Some females mature at 4 years. The greenling has been aged to 12 years, but few probably live longer.

Females are oviparous and these fish are fall spawners with nesting noted in October- November off Washington and British Columbia. Females migrate down to the males, lay their blue eggs in nests which the males guard until they hatch. Feeding occurs during the day and they are inactive at night, with their preferred menu being : shrimps, crabs, worms, octopi, brittlestars, snails and small fish.

 

 

 

 

References:
Probably more than you want to know about the fishes of the Pacific Coast, Milton Love, Really Big Press, California, 1996

Coastal Fishes of the Pacific Northwest, Andy Lamb and Phil Edgell, Harbour publishing, BC, 1986

Other members of the Class Actinopterygii 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.
Dec. 2001 Jill Scherenke Dec 2001 (PC) Germany

 

Enteroctopus dolpheni: Giant Pacific Octopus: The Race Rocks Taxonomy

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Enteroctopus dolpheni: Giant Pacific Octopus: The advanced eye of a mollusc. Photo by Ryan Murphy

Getting up close and personal was one of the things that former Ecoguardian Ryan Murphy was able to do very well underwater.. Consequently he produced the following interesting images from underwater.

We frequently encounter Octopus while diving at Race Rocks. They blend in very well with the algae and can change colors rapidly. Often the best way to see them is to spot their large (1-2 cm) white suckers in a crevice or cave. According to the website below, “Although it is very unusual to find an individual over 45kg, one large individual captured just near Victoria in 1967 weighed 70 kilograms (156 pounds) and was almost 7.5 meters ( 23 feet ) from arm tip to arm tip.

Smaller animals occur occasionally in low intertidal pools on rocky shores, larger individuals generally subtidal to depths of 100m; along North Pacific rim from northern Asia to California;

One of the largest octopus species known, the largest specimen on record with a total arm spread of 9.6m and a weight of 272 kg; dorsal mantle length usually over 20 cm; weight sometimes exceeding 50 kg; body ovoid, with extensive skin folds, red to reddish brown above, pale below; ocelli absent; arms 3-5 times body length, lacking specialized enlarged suckers and large truncate papillae; hectocotylus large, about one-fifth the length of the third right arm; with 12-15 lamellae on the outer demibranch of each gill; gill lamellae 25-29; ink dark brown; eggs measuring 6-8 mm by 2-3 mm, planktonic larva with a single row of chromatophores on each arm; borne in capsules on long stalks, these entangled and cemented together to form long festoons.

The Giant Pacific Octopus, (Enteroctopus dofleini , Hochberg, 1998) was formerly classified as : Octopus dofleini (Wulker, 1910)

 

Giant Pacific Octopus 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 recently in June 2002, became the subject of a webcast and an impromptu dissection on the shore.

Video on Octopus necropsy

Domain: Eukarya
Kingdom: Animalia
Phylum: Mollusca
Class: Cephalopoda
Order Octopoda
Suborder: Incirrata
Family :Octopodidae
Genus: Enteroctopus
Species: dofleini (Hochberg, 1998)
Common Name:  Giant Pacific Octopus
Although E.dofleini has been used extensively in laboratory studies, its natural history is still poorly known. The life cycle is thought to be 4-5 years. Eggs are laid throughout the year, though mainly in the winter, and development takes 5-7 months; hatching peaks in the early spring. The young are pelagic for a short period, probably about 1 month.

The three images above of a baby Octopus were taken in the intertidal zone near the docks by
Ryan Murphy in July 2004.

The adults feed on crustaceans (shrimps and crabs), mollusks (scallops, clams, abalones, moon snails, and small octopuses, and fishes ( rockfishes, flat fishes, and sculpins). Large crabs are stalked and then caught with a sudden flick of one or more arms; empty crab carapaces, shiny shells, and bones often litter the entrance to a lair. The octopus takes smaller shrimps and fishes by slowly arching its body over a seaweed bed, then suddenly pouncing, and enclosing the area in a canopy formed by the web membrane that joins the basal parts of adjacent arms. The sensitive arm tips are then inserted into the impounded area to search for food.

  • Two mesozoan parasites charactersictically occur in the kidneys of E. dofleini: Dicyemennea abreida and Conocyema deca.

This octopus is fed upon by seals, sea otters, dogfish sharks, lingcod, and man. It supports small commercial fisheries in Alaska, Canada, Washington, Oregon, and Northern California. Locally, it is also used by halibut fishers as bait.

Literature Cited:

Robert H. Morris, Donald P. Abbott, and Eugene C. Haderlie, Intertidal Invertebrates of California

Eugene N. Kozloff, Marine Invertebrates of the Pacific Northwest

octopus and diverLink to an assignment on Biodiversity submitted to us by
Shawna Millard Biology 202 at Bellevue Community College, Washington.

 

 

Return to the Race Rocks Taxonomy

This file is provided as part of a collaborative effort by the students, faculty and volunteers of Lester B. Pearson College .  This file was started by: Amanda Muscat PC yr 27, Dec. 2001.

Plankton Lab

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BACKGROUND: Microscopic plankton can be can be collected in a way that allows us to determine densities of the organisms, and therefore compare different pelagic environments. We have already seen how plankton populations can vary from part of the ocean to another. In order to quantify plankton, the following method is suggested. You are urged to come up with your own research problem concerning plankton populations and then proceed to use the following techniques to investigate. Although this lab refers to Pedder Bay on Vancouver Island,, It could be modified to suit any location.

PROCEDURE:

In order to determine densities of organisms, we first have to know the volume of the water from which the sample is taken.

  • You will use a plankton net with a small propellor driven counting log to measure distance travelled in the water that is sampled. To calibrate the log, measure off a distance on the docks, read the dial at the beginning of the trial, drag it through the water the length of the measured section, and the difference in the reading at the end of your tow will be the length of your cylinder of water.
  • Now calculate how many counts on the dial there are per meter.
  • Divide the number of counts per meter into the number of counts through the distance you drag the net for your sample. This gives you a number of meters in length for the sample cylinder.
  • Measure the diameter of the net opening and now calculate the volume of sample taken from the open ocean. The formula for volume of a cylinder is V=(pi X radius squared) X h(meters)

 What is in The sample?

  • Note the total volume of the sample taken. Then remove a representative subsample of 1 ml.
  • Place the 1ml sample in a slide with a measured viewing chamber. Count numbers of individual species in representative quadrats. Obtain the average, and multiply this number by the total number of quadrats available.

 Density determination.

  • .Now calculate the density of the individual species in the sample . i.e. number per cubic cm. then per cubic meter.
  • Calculate the number for a larger area e.g. Pedder Bay ! Hint treat it as a segment of a cone for volume determinations, use a marine chart to determine the measurements of the bay..

Micro-photographs of plankton from Pedder Bay:

Pedder Bay frequently has blooms of Mesodinium rubrum. This organism turns the bay a deep wine colour . It is not a poisonous red tide, but we have noticed that when it is pumped up into seawater tanks, it will easily smother some of the filter feeders such as sponges. Blooms often coincide with nutrient loading followed by a period of sunny weather.

 

Histrionicus histrionicus: Harlequin duck–The Race Rocks Taxonomy

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Histrionicus histrionicus –Harlequin Duck

In the fall of 2006, there was a large flock of males and females around the shores of the island. They were frequently visible in the waters and shoreline around the docks. These pictures were captured on the remote camera 5 by Pam Birley.

Interesting Facts:

  • English name from characters in Italian comedy that wear a mask and have an oddly painted costume
  • Locally may be called “rock ducks” due to their habit of staying out on rocks.
  • Population of 200 – 300 thousand on the West Coast but endangered on the Atlantic Coast
  • A group of up to 30 harlequins overwinter at Race Rocks, arriving in early November and departing in the spring, numbers vary as they come and go during that time.

Identification:

  • Length: 12 inches
  • Wingspan: 26 inches
  • Small diving duck
  • Small gray bill
  • Dark wings

Males have a striking feathers with dark blue, dark orange, and white streaks
Females are discrete and have a subtle brown color that camouflages them for nesting

Ryan Murphy has an album of images of Harlequin ducks which he took while he was an Ecoguardian at Race Rocks- 2009-2011.

Biotic Associations:

  • Predation from Sea Lions ( We have seen them leave the water and come up on the rocks when sea lions are near.)
  • Spend majority of time feeding in Kelp Beds on aquatic invertebrates and lesser quantities of fish.

Food:

Freshwater invertebrates

  • Fish eggs consumed when available
  • Use their stubby bill to pry invertebrates such as snails, limpets, crabs, chitons, and mussels from the rocks
    during the winter months
  • In the late winter months they feed on herring spawn in large congregations.

Domain : Eukarya
Kingdom:  Animalia
Phylum : Chordata
Subphylum:  Vertebrata
Class : Aves
Order:  Anseriformes
Family:  Anatidae
Genus:  Histrionicus
Species: histrionicus
COMMON NAME: Harlequin Duck

See other posts on this website with reference to Harlequin Ducks

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.

This file was originally produced by Dec. 2001 Karim Ladha (PC yr 27)

 

Cepphus columba: Pigeon Guillemot–The Race Rocks Taxonomy

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rmmar2609piggguil

Pigeon Guillemots arrive in early January, some still in their mottled winter plumage. Their numbers build and nesting takes place in late spring. A favourite foraging area is in the main channel in font ( to the North) of the Race Rocks docks. They may number up to 100 in the water, diving down in the current and coming up with small fish, especially gunnels.

Ryan Murphy has done some amazing telephoto shots starting in February of 2009 of Pigeon Guillemots such as those below.  They are included in a set here on his Flickr site.

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Four samples of photos of Pigeon Guillemots by Ryan Murphy

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Winter Plumage on Pigeon Guillemots, photo by Pam Birley by the Remote control Camera 5

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Winter Plumage of Pigeon Guillemot. photo by Raisa Mirza


Description: The pigeon guillemot has an average size of 12-14”. Its summer plumage is black with large white wing patches interrupted by black stripes.

It is interesting to note that in winter, its head and upper parts lighten slightly, however in all seasons feet and bill lining are brilliant red. In the spring it can be heard making a high whistle.

How and what they eat: The Pigeon Guillemot feeds by diving and taking up small fish. Some examples are: Penpoint Gunnels or “Blenny”, sand lance, smelt, and sculpins.

Habitat: This species resides in rocky coastal areas, with shallow inshore waters as its feeding grounds. Nest cavities are found amongst holes and rock crevices on the West, North East and South sides of Great Race Rocks. Some habitat for nesting was created years ago when blasting for the helicopter pad produced rubble under which they could tunnel..

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Ryan Murphy took this picture of a pigeon guillemot having just caught a gunnel.

Lumpenus sagitta, pacific snake prickleback captured by Pigeon guillemot

Lumpenus sagitta, pacific snake prickleback captured by Pigeon guillemot, Ryan Murphy photo.

Predators: Seagulls are predators of pigeon guillemot eggs. At Race Rocks, the main threat is predation by Bald Eagles, Peregrine falcons and nest predation by River Otters.

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Summer ecoguardian Adam Harding was able to take pictures of a the chicks in a guillemot nest in the summer of 2011. The nest was located at the end of the low rock wall West of the science house

 

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1 or 2 greenish or whitish, dark-spotted eggs are laid in a crevice or burrow. This nest burrow had been abandoned,perhaps due to predation, at the end of the season eggs were still present unhatched in the burrow. The light keeper’s assistant is shown here-1984-

Pigeon Guillemots

Pigeon Guillemots photo by Ecoguardian Courtney Edwards in March , 2014

The slide show above was made from pictures taken by Pam Birley in 2007

Kiprop made this video of the Guillemots jostling for position on the rocky shore on the West side of the island.

slide show of mating guillemots by Pam Birley was made from camera 5 screen captures.

Video of pigeon guillemots on the island and out in the passage where they dive and forage.[/caption]

Return to the Race Rocks Taxonomy and Image Gallery

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 text of this taxonomy was done in Dec. 2001 by Anthony Woodside, PC Year 27

Gersemia rubiformis: Sea strawberry–The Race Rocks Taxonomy

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Gersemia rubiformis –Photo by Dr. A.Svoboda

In the following video, the soft pink coral Gersemia rubiformis is highlighted. It grows at 7-10 meters over a 3 square meter area off peg #3.  note the retraction of the colony when it is disturbed. Also note the other associated invertebrates in the same area.

The following video shows in close details the characteristics of the soft pink coral (Gersemia rubiformis) found at Race Rocks. Soft corals are mostly sub-tidal. A soft coral has spicules of calcium carbonate within it, so it is moderately firm, but it does not have a completely calcified skeleton, like that of reef-building corals of warmer seas, or even like that of the cup coral of our coast. The polyps of soft corals have eight tentacles, each with delicate side branches. This establishes their relationship to sea pens and to most of the colonial reef-building corals. This colonial invertebrate forms a lumpy colony, sometimes 10 or 15 cm in diameter, whose colors range from cream through orange to deep pink elsewhere, but are consistently deep pink here at Race Rocks. The lumps, when the polyps have withdrawn, slightly resemble raspberries, which belong to the genus Rubus; hence the specific name rubiformis. Extended, the individual polyps stick out about 5mm beyond the lump to which they belong.   Filmed by Jean-Olivier Dalphond and Damien Guihen on a sunny day at Race Rocks.


Gersemia rubiformis – a soft coral found underwater at Race Rocks. Usually it is found at the depth of 8 to 10 meters with an amazing variety of many other invertebrates. Here, no invertebrate is found growing on its own, they always occur in association with other invertebrates.

Gersemia occurs in fairly big pink patches in rather greater depths in the ocean but there are some small patches of it along the North cliff of Race Rocks. The lumpy colonies it forms usually are 10 to 15 cm in diameter.

Gersemia grows at the shallow depth because of the availability of nutrients there. Emerging from the walls are small pale pink polyps

Extended, the individual polyps stick out about 5 mm beyond the lump to which they belong. These polyps have small tentacles at the end. Each polyp has 8 of them, each with delicate branches which are able to catch masses of plankton for food. The vertical structure of the colony allows the polyps to be filter feeders and strain out plankton and other drifting organisms from the water column.

Embedded within the body wall of the polyp are millions of microscopic, photosynthetic organisms, known as zooxanthellae. They live symbiotically, provide food and fuel and absorb many of the waste products of the polyp. Without the zooxanthellae, the corals could not exist. It is the zooxanthellae that contains necessary chemicals for the adequate production of calcium carbonate, for reef forming types of corals. However Gersemia does not have a completely calcified skeleton, like that of reef-building corals of warmer seas. Zooxanthellae are also responsible for providing much of the colour in corals, which usually range from cream through orange to deep pink elsewhere, but are consistently deep pink in Race Rocks.
CLASSIFICATION:
Domain: Eukarya
Kingdom: Animalia
Phylum: Cnidaria
Class: Anthozoa
Order: Alcyonacea
Family: Nephtheidae
Genus: Gersemia
Species: rubiformis
Common name: Sea Strawberry

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. Ania Pawlicka——- PC yr 27, 2001

 

Ligia pallasii: Sea Slater –The Race Rocks Taxonomy

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video of sampling of populations of Ligia sp

 

During the Johan Ashuvud project 2004, students explored the intertidal with Garry. 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

The central part of this video has a section on Ligia sp.

Sexual dimorphism in body proportions is marked in L.pallasii. Males, with their large, laterally expanded ephemeral plates, have a length/width ratio of about 1.6; females and immature males are narrower, with a corresponding ratio of about 2.1. Half- moulted males are occasionally found in which the rear half of the body has moulted and is abruptly significantly wider than as yet unmoulted front half, an odd sight, usually several days after the posterior moult.On the walls of cliffs and sea caves, the larger and broader males often cover and shield the females and juveniles.

L.Pallassi prefers sea cliffs. At Race Rocks, the loose upper intertidal rocks and crevasses on the Western side of the main island provide ideal habitat. There are differences in the osmoregulatory responses shown by these species associated with their behavior and ecology.The slower -moving pallasii lives permanently in cool, moist habitats characterized by fluctuating hypo-saline condition. L.Pallasii are air breathers with gill-like pleopods not equipped with tracheal trees.The respiratory pleopods must be kept moist to function properly.This is done by immersion or by dipping the tail in water in such away that the uropods serve as capillary siphons.

Ligia species are fed upon by birds, especially gulls, and by the intertidal crab. Life span of L.pallasii is 1.5 to 2 years , with breeding occurring in spring and early summer, and the average brood size is 48 plus or minus 11 young.The overall sex ratio is 1:1.

Domain Eukarya
Kingdom Animalia
Phylum or Division Arthropods
Class Crustacea (crustaceans)
Order Isopoda
Family Ligiidae
Genus Ligia
Species pallasii
COMMON NAME:sea slater

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. Dec 2005- Palwasha Hussain Khel