Hemigrapsus oregonensis: Shore crab-The Race Rocks Taxonomy

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hemigrap?

Hemigrapasus oregonensis photo by Anne Stewart. In log

Physical description:
Hemigrapsus oregonensis (Beige shore crab) has dull olive-coloured hairs on its legs and it is lack of reddish spots on the claws. The legs have abundant setae and the chelipeds have no purple spots, but have yellow or white on the tips. There are 3 teeth on the anterolateral margin of the carapace. It has a carapace width ranging up to 34.7mm for males and 29.1 mm for females. It is usually dark or grayish green in color, but white or mottled patterns are common, especially among juveniles. It also has a four-lobed anterior margin.

Global Distribution:
Hemigrapsus oregonensis occurs from the high to low intertidal zones of bays and estuaries from Resurrection Bay (Alaska) to Bahia de Todos Santos (Baja California).

Habitat:
It is most commonly found under rocks, throughout the intertidal zone. They live on open mud flats and in mats of the green alga Enteromorpha and beds of the eelgrass Zostera. It can also be found in rocky habitats within estuaries, gravel shores and in estuaries where it constructs burrows in mud banks. Generally, it prefers more protected and slow water current area. Hemigrapsus nudus always stay together with Hemigrapsus oregonensis.

Feeding:
Hemigrapsus oregonensis feeds mainly at night. The diet of it consists primarily of diatoms, sea lettuce and green algae, but occasionally includes meat if it is available. It scraps up diatoms and crop algae. It also preys on a wide range of small invertebrates, scavenges if it is possible. It can filter-feed by using its third maxillipeds.

Predators:
Predators include shorebirds and Carcinus maenas. A type of red ribbon worm is also a predator of the eggs of Hemigrapsus oregonensis. .

Reproduction:
In northern waters ovigerous females are seen from February to September. The number of eggs carried by the female is ranged from 100 to 11,000 (with an average number of 4,500). Hatching occurs from May to July with one pre-zoeal stage occurring inside the egg. Planktonic larvae develop through five post-hatching zoeal stages. The larvae typically spend five weeks in the plankton.
In August some females produce a second brood which hatches in September. Time from egg deposition to adult recruitment is variable and depends on several factors: the quantity and quality of food available, water temperature and salinity. Altogether it takes about 8-13 weeks for a brood to hatch, metamorphose and be recruiting into the adult population.

oregonshorecrab

Oregon Shore crab G.Fletcher photo

Scientific Classification
Domain Eukarya
Kingdom Animalia
Phylum Arthropoda
Class Crustacea
Order Decapoda
Family Grapsidae
Genus Hemigrapsus
Species oregonensis
Common Name: shore crab

Sea otters, currently abundant in Elkhorn Slough and only historically abundant in more northern bays, are limiting Hemigrapsus oregonensis populations. One paradigm in the study of exotic species is that healthy ecosystems, with a full complement of native species, are more difficult to invade than modified systems. In this case, sea otters may be eating the introduced species, as evidenced by Hemigrapsus oregonensis parts in recent scat analyses. While the current West Coast range for Hemigrapsus oregonensis is Morro Bay, California to Barkley Sound, British Columbia, studies at Elkhorn Slough may change how scientists and resource managers predict the impacts of introduced marine species.”

References:(accessed 2005)
http://oregonstate.edu/~yamadas/crab/ch9.htm
http://people.wwc.edu/staff/cowlda/KeyToSpecies/Arthropoda/Crustacea/Malacostraca/Eumalacostraca/Eucarida/Decapoda/
Brachyura/Family_Grapsidae/Hemigrapsus_oregonensis.html
http://oceanlink.island.net/oinfo/intertidal/arthropod.html
http://www.nwmarinelife.com/htmlswimmers/h_oregonensis.html
http://www.ci.edmonds.wa.us/Discovery_Programs%20Website/Crustaceans.html
http://oregonstate.edu/~yamadas/crab/ch5.htm

Marine Invertebrates of the Pacific Northwest by Eugene N. Kozloff

by Student  Karyn Wong, PC yr 32 -2005
Other Members of the Phylum Arthropoda at Race Rocks.

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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.

Corallina officianalis: The Race Rocks Taxonomy

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geniculatecor1

Corallina officianalis – all photos by Ryan Murphy

Phylum: Rhodophyta
Class: Florideophyceae
Order: Cryptonemiales
Family: Corallinaceae
Corallina officinalis (L.)

geniculate corallinacostaria

Description: This plant is erect, 4-6 cm. high, dark pink in colour, arising from an encrusting basal layer attached securely to the substrate. The erect portion is a branched system of jointed segments. The segments below are cylindrical, about 0.75 mm. diameter; above slightly cgracilis2compressed and about 1 mm. broad. The axes are clothed with narrower short lateral branchlets that shorten to the apex. Branching pattern gives the plant a clumpy appearance.

Habitat: On rocks in the lower intertidal and upper subtidal zones and in tide-pools.

 

Pacific Coast Distribution: Alaska to Mexico.

 
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 PC yr 26

 

Desmarestia intermedia : The Race Rocks Taxonomy

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desmarest

The wiry branches of Desmarestia  intermedia.. Photo by Ryan Murphy

All the Desmarestias have high acid content. You often see them bleached out on the beach, and they will also bleach any adjacent algae.

Phylum: Phaeophyta
Class: Phaeophyceae
Order: Desmarestiales
Family: Desmarestiaceae
Desmarestia intermedia (Postels and Ruprecht)

Description:  This plant is dark brown in colour, up to 60 cm. high, very profusely branched, wiry; branches mostly compressed, about 1.5mm. wide except near the base, where the main axes are up to 5 mm. wide and cylindrical. Branching is fasiculate below, mostly alternate above, occasionally opposite.

Habitat:   On rocks in the upper subtidal zone.
Pacific Coast Distribution: Bering Sea to Oregon.
Robert Scagel, 1972
Other Phaeophytes or Brown 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 2005

 

Directory of OceanQuest Assignment Resources:

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Overview: Are you prepared to take on the challenge of OceanQuest? You are expected to be an active participant in helping to build a valuable resource database for a unique sensitive environment.

The basic starting resources you will use come from www.racerocks.ca but our vision for the future is that you may actively develop a set of internet resources for your own unique ecological area.

Link to The OceanQuest GIS With Curriculum Guide
NOTE: The link to the GIS which ran on an outside server arranged by the Open School has been discontinued.. The other curruculum materials are still valid however on this site.
Topic 1 :
BIODIVERSITY
Some of the following files from www. racerocks.ca were used in the building of the OCEANQUEST website.
Lesson: 1. Structure and Function of Ecosystems :
How can we model ecosystems in order to understand how they work ?
Student Activities: Objectives:
Procedure :
1. Introduction
2. Horizontal distribution

  • Objectives:
    Procedure:

    • 1. Use the remote camera.
    • 2. Use the dichotomous key for identification.
    • 3. Determine the sector from aerial view of horizontal distribution.
    • 4. Field techniques to quantify distribution.
    • 5. Describe the Role of organisms in determining horizontal distribution.
    • 6. Design your own horizontal structure analysis.
    • 7. How do Anthropogenic Impacts affect Biodiversity.
      • Objectives:
        Procedure:
3. Vertical Distribution

  • Objectives:
    Procedure:

    • 1. Use the remote camera.
    • 2. Use the Dichotomous key for identification.
    • 3. Vertical Stratification of Tide Pools
    • 4. Subtidal vertical stratification with seaweed canopy.
    • 5. Vertical Stratification in the water column.
    • 6. Vertical Stratification in Soil
    • 7. Design your own vertical structure analysis.
4. Biotic Components
List of birds and mammals most frequently observed from the remote camera 5.
5. Rare and Endangered Species
6. Coastal Classification System

  • Objectives
  • Procedure:
7. Abiotic Components (Topic 2 below)
8. Ecosystem Function

  • Objectives:
  • Procedure:
9. Biogeochemical cycles

  • Objectives:
  • Procedure:
10. Extension..Other ecosystems– structure and function.
Lesson:
 2. Why not Adopt an Ecosystem?
Use the internet as a means to get groups to collaborate to provide an educational resource while ensuring the stewardship of their own local ecological resources.
Objectives:
Procedure:
1. Identify the area
2. Establish goals and time lines
3. Establish a baseline inventory
4. Class project to provide a taxonomy
5. Use technology to document the area
6. Monitor for Structure and Function: (See topic 1.)
7. Submit site for inclusion in GIS
8. Obtain tiff-referenced aerial photography
9. Assemble a web-site to carry the information.
10. Create a list of the Ecosystem Services and Natural Capital of the area.

11.Set up a weather monitoring Station.
TOPIC 2: ABIOTIC FACTORS
Lessons: 1. Selected Abiotic Factors (such as Barometric Pressure) :

The effects of physical factors on the life of an ecosystem is often taken for granted. Here we give you the chance to investigate some of the unique ways that organisms have evolved in order to adapt to the physical conditions of their environments.
Objectives:
Procedure:
1.Introduction
2. Wind Speed and Direction
3. Barometric Pressure
4. Lightning
5. Change through time: Salinity and Temperature.
2. Limiting Factors and the Ecological Niche
Objectives:
Procedure:
1. Introduction
2. GIS activity
3. and 4and 5. Contrast limiting factors in two closely related species.
6. Natural Selection
7. The Ecological Niche as determined by limiting factors
8. Adaptation: A classic study of limiting factors: The Bumpus sparrows.
9. Extension: Central Tendency and Variability.
Topic 3 : ANIMAL BEHAVIOUR
Lessons
 1. Population Monitoring:
An activity which allows you to contribute to a scientific database for the census of animals
Objectives:
Procedure:
1. Census of the populations, and the use of the dichotomous key.
2. Race Rocks population numbers and sector designations.
3. Weather correlation to population levels.
2. The Ethology Assignment:
An activity that may allow you to look at the behaviours of animals in a new way
Objectives:
Procedure
1. Preliminary Observation.
2. Collecting Data.. The ethogram and the time budget.
3. Using the dichotomous key for identification.
4. Compiling the Ethogram
5. Preparing the Time Budget
6. Doing a report and submitting results to the GIS
7. Extension material

Corallina vancouveriensis: coralline algae–The Race Rocks Taxonomy

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cvancouveriensis

Corallina vancouveriensis in a tide pool, some bleached white by the sun

Phylum: Rhodophyta
Class: Florideophyceae
Order: Cryptonemiales
Family: Corallinaceae
Corallina vancouveriensis (Yendo)

All photos are by Ryan Murphy.

c.vancouveriensis

More C. vancouveriensis in a tide pool

Description: This plant is erect, 4-10 cm. high, deep purple in colour, arising from an encrusting basal layer attached securely to the substrate. The erect portion is a branched system of jointed segments. The segments below are cylindrical, about 0.75 mm. diameter; above slightly compressed and about 1mm. broad.  The axes are clothed with narrower short lateral branchlets, all approximately the same length. Branching in the lower region is distichously pinnate with branches usually simple; above distichously pinnateor verticillate with branchlets usually pinnately subdivided.

Habitat: On rocks in the lower intertidal and upper subtidal zones and in tide-pools.
Pacific Coast Distribution: Alaska to Mexico. Robert Scagel, 1972
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 PC yr 27

 

Laminaria groenlandica : The Race Rocks Taxonomy

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laminaria groenlandica

Laminaria groenlandica blade showing deep dissections==All photos by Ryan Murphy

Phylum: Phaeophyta
Class: Phaeophyceae
Order: Laminariales
Family: Laminaracea
Laminaria groenlandica (Rosenvinge)


Description: This plant is dark brown to black in colour with a conspicuous holdfast, blade, and stipe. The stipe varies in length from 10 cm. or less to 60 cm. in length, from terete to complanate, and is 3-4 mm. diameter. The holdfast is relatively small, made up of many branched root-like structures. The blade is 60-90 cm. long, 7-12 cm. wide, sometimes deeply dissected, and it may be completely smooth, with only two rows of bullations, or densely bullate over the entire surface. The base of the blade is broadly rounded.
Habitat: On rocks in the upper subtidal zone.
Pacific Coast Distribution: Bering Sea to Oregon. Robert Scagel, 1972
Other Phaeophytes or Brown 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 PC yr 26

 

Laminaria saccharina: The Race Rocks Taxonomy

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lsaccharina

A young Laminaria saccharina showing bullations. All photos by Ryan Murphy

Phylum: Phaeophyta
Class: Phaeophyceae
Order: Laminariales
Family: Laminaracea
Laminaria saccharina (L.) Lamouroux

Description: This plant is rich brown colour with a conspicuous holdfast, blade, and stipe. The holdfast is composed of branched root-like structures. The stipe varies in length from 5 to 50 cm., from 6 to 9 mm. in diameter, is terete, flattening above the base of the blade.   The blade is smooth, with or without two rows of bullations, sometimes undulate, and tapered to broadly rounded at the base; it is 12-18 cm. broad and 2.5-3.5 m. long.
Habitat: On rocks in the lower intertidal and upper subtidal zones.
Pacific Coast Distribution: Alaska to Oregon and in the Channel Islands, California.  Robert Scagel, 1972

Other Phaeophytes or Brown 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 PC yr 26

 

Acrosiphonia coalita: The Race Rocks Taxonomy

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chloro3 copy

The fine filamentous green algae <i>Acrosiphonia sp.</i> photo by Ryan Murphy

Classification :
Scientific classification
Domain: Eukaryota
Kingdom: Viridiplantae
Phylum: Chlorophyta
Class: Ulvophyceae
Order: Acrosiphoniales
Genus: Acrosiphonia
Species: coalita

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 2005–Ryan Murphy

 

Hirundo rustica: Barn Swallow

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UPDATE 2023 Derek Sterling has taken some excellent photos and written about the return of barn Swallows to Race rocks

This video shows the barn swallow fledglings in their nest.

June, 2005: the adult birds were observed going in and out of the vents on the north side of the water desalinator building on Race Rocks.

June-July 2006: This nest was built of mud, lined with goose and gull feathers under the concrete stairway of the Marine Science Centre. (Tis structure was replaced with a wooden staircase in 2020) On July 4, they were seen to be flying in and out of the opening frequently. Barn swallows are frequent nesters in rural areas all throughout western Canada. They choose a nesting site always located in an assured dry location.Frequently this is an out-building on a farm with an open door or window. They have excellent aerodynamic  maneuvering control as they fly quickly over open areas catching insects with a wide opening mouth. They are valued for their voracious appetite for mosquitoes and flies. With their food being flying insects, the island certainly provides an abundant supply of the kelp fly Coelopa vanduzeei

These pictures were taken of a newly-fledged family on a balcony in nearby Metchosin. The juvenile birds were waiting to be fed

An interesting question was posed by someone recently. Since swallows fly from the brightly lit outside rapidly into a dark building, do they have a specially evolved vision system for rapid dark adaptation? We know that bats do this with their echolocation system, but birds don’t have that ability.

Domain: Eukarya
Kingdom: Animalia
Phylum: Chordata
Sub-phylum: Vertebrata
Class: Aves
Order: Passeriformes
Family: Hirundinidae
Genus: Hirundo
Species: rustica
Common Name:Barn swallow

Physical Description:
The barn swallow is the only one of its family with a deeply forked tail. It can be identified by its rusty under parts and orange rump as well as a dark orange forehead and throat. Like all swallows, it is a strong and elegant flyer. Its legs and bill are short, but it has a wide mouth for capturing insects. These birds are generally around 15 cm in length.


Habitat:
True to its name, the barn swallow is common near farms. It builds a nest of mud on the timbers of barns and other such buildings. It commonly inhabits caves and areas

underneath bridges. Barn swallows are migratory birds, and fly south from North America to South America for the winter.

Reproduction:
The length of incubation for barn swallow eggs is 13 to 17 days. They lay in open-cup nests made of mud pellets and grass. The eggs are speckled and nesting begins in the second half of May. If the pair of swallows is successful, two broods are raised each year.

Feeding Habits:
This swallow feeds exclusively on insects. Hunting typically takes place on or close to ground level. However, on summer afternoons, they can be seen flying high in the air. The barn swallow simply follows the desired insects and catches them in flight.

Global Distribution:
The barn swallow can be found in almost all parts of Canada and the USA. It typically inhabits every continent except Australia. It is a resident of rural areas, and populations are most heavily concentrated in southern Texas and central USA.

Predators:
Predators are most commonly cats and raccoons. When a predator approaches, the entire colony will launch an attack in a display of aerial acrobatics.

Interesting Fact:
The barn swallow’s song is long and twittering. They are commonly known to perch on wires and are often seen in large, mixed flocks.

References:
. Brunn, B. C.S. Robbins, Singer and H.S. Zim. 1966. A Guide to Field Identification, Birds of North America. Golden Press. New York, NY.
. http://www.americanartifacts.com/smma/per/b4.htm
. http://www.museum.gov.ns.ca/mnh/nature/msbirds/bns0261.htm

 

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.

December 2005-  Chelsea Howard, Nfld. year( PC year 32)

Ulva lactuca

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ulvaporphyra

Ulva lactuca images by Ryan Murphy

Description: This plant is light to dark green, erect, lanceolate to broadly ovate, often ruffled along the margins, 18-60 cm. high; at times irregularly split into broad lobes, tapering abruptly near the base to a short stipitate region and a small discoid holdfast of rhizoidal cells.

Habitat:  On rocks and epiphytic on other algae in the upper intertidal zone; often floating on mud flats in the lower intertidal zone in quiet bays and lagoons.

Pacific Coast Distribution: Bering Sea to Chile.

Robert Scagel, 1972
Scientific classification
Kingdom: Plantae
Phylum: Chlorophyta
Class: Ulvophyceae
Order: Ulvales
Family: Ulvaceae
Genus: Ulva
Species: U. lactuca
Ulva lactuca
Linnaeus, 1753

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 2005-Ryan Murphy