Monthly Archives: December 2005

Oncorhynchus kisutch: Coho Salmon- The Race Rocks taxonomy

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Physical Description:
At sea, they are coloured metallic blue on back, with silvery sides. Also have irregular black spots on back, upper fin and lower dorsal fin. Gums are white at base of teeth and fins are tipped with orange.
Maturing males in fresh water will have bright red sides, with their head and back coloured bright green, and often dark on their bellies. Females are less brightly coloured, with bronze to maroon coloured sides.
Fry is orange with dark spots concentrated on back and fins.
Can also be identified by their “hook-nose” jaws; their upper jaw hooks down slightly towards the lower jaw.
Coho salmon can grow to be a length of 79cm and weigh 14kg.Global Distribution:
Coho salmon spawn in coastal streams from Northern Japan to the Anadyr River in Siberia, and from Monterey Bay in California to Point Hope in Alaska. They can be found at sea from Japan and Korea to the Chukchi Sea and southeastward to Baja, California. They have a center of abundance between Oregon and southern Alaska.
Humans have introduced Coho salmon to the Great Lakes with enormous success. Attempts to introduce them to the Atlantic coast of North America between 1901 and 1948 failed miserably.

Habitat:
Coho salmon are extremely adaptable; they occur in nearly all accessible bodies of fresh water and utilize nearshore and offshore environments during lifecycle. However, they prefer to stay close to shore to avoid predators and will not be found deeper than 30m.
Coho salmon will not be found in temperatures lower than 6.5°C or higher than 21°C, and those that live off of the southern United States have been known to migrate north as the temperature rises.
Coho salmon prefer to spawn in streams with low velocity, shallow water and small gravel. Most Coho fry stay in the stream where they are born for a over a year in schools that are located in quiet areas free of current.

Reproduction:
Coho salmon, like all salmon, are anadromous fish, which means that they spend most of their life feeding at sea, but return to fresh water to breed (and always return to the same place where they were born and lived as fry). Coho salmon are also oviparous, which means that they reproduce by the female laying eggs and the male fertilizing them after they leave the female’s body.
Because of the large spread distribution, spawning occurs over a very large period (between October and March). Generally, more southern spawning occurs later during this time period. More specifically, spawning in British Columbia occurs in October and November. The closest spawning river to Race Rocks is the Goldstream river just north-west of Victoria.Spawning occurs at night. A female will dig a nest, called a redd, and deposit an average of 2 400 to 4 600 eggs (but up to 7 600). The male will fertilize the eggs as she lays them. A female can make several redds, and usually deposits all of her eggs between them.
The eggs develop during winter and hatch into larvae in early spring. The warmer the temperatures, the faster the eggs develop. After hatching, the larvae stay under the gravel for a few weeks and then emerge as fry.
The spring following this, they will start their journey towards the sea. Females and some males will return to spawn after three years. Most males (known as jacks) will return after two years to mate.
Coho salmon die 3-24 days after mating.

Feeding:
As larvae, they feed off of their yolk (which is still attached to them). They do not emerge from the gravel as fry until this source of nourishment has run out. It is then that they start eating aquatic insects, zooplankton, small fishes, and the remaining carcasses of the salmon that died after spawning.
At sea, Coho salmon feed on fishes like herrings, anchovies, sand lances and rockfishes, and invertebrates such as krill and squid.
Coho salmon only feed during the day.

Predators:
Humans are a Coho salmon’s biggest threat. They are considered prize sport fish because of the ‘memorable’ fight that they put up, and make up for half of the recreational salmon catch in British Columbia. Coho salmon have also developed a reputation for being particularly tasty, making them the perfect victim of the commercial fishing industry. It is estimated that the Coho population off of California is 6% of what it was in the 1940s due to the fishing industry. And British Columbia still ‘wins’ for the highest catch per year in North America!
In addition to humans, Coho salmon are eaten by some larger fishes, as well marine mammals like seals, orcas and white-sided dolphins.

Interesting fact:
All salmon undergo smoltification upon entry to the sea in order to live in sea water. This process works both backwards and forwards: it allows them to leave the sea for fresh water, and to leave fresh water for the sea.
However, some Coho salmon have been known to live in fresh water their whole lives, and these freaks of nature are known as residuals.

Domain Eukarya
Kingdom Animalia
Phylum Chordata
Subphylum Vertebrata
Class Actinopterygii
Order Salmoniformes
Family Salmonidae
Genus Oncorhynchus
Species kisutch
Common Name: coho salmon

Resources:

1. Coho Salmon Facts. 1996. Pacific States Marine Fisheries Commission. November 11, 2005. http://www.psmfc.org/habitat.edu_Coho_facts.html
2. Coho Salmon: Wildlife Notebook Series. 1994. Alaska Department of Fish & Game. November 11, 2005. http://www.adfg.state.ak.us/pubs/notebook.fish.Coho.php
3. Deutsch, A. Coho Explained. 2005. Pacific Coast Salmon Coalition. November 11, 2005. http://www.Cohosalmon.com/Coho_explained.htm
4. Hart, J.L. Pacific Fishes of Canada. Ottawa, ON: Information Canada, 1973.
5. Love, Milton. Probably More Than You Want to Know About the Fishes of the Pacific Coast. Santa Barbara, CA: Really Big Press, 1996.

References: Andy Lamb and Phil Edgell: “Coastal fishes of the Pacific Northwest”

                  J.L Hart: “Pacific fishes of Canada”

Other Members of the Class Actimnopterygii 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: Amanda Judd, OntarioYear 32

Phyllospadix scouleri: surf grass– Race Rocks taxonomy

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Domain: Eukarya
Kingdom: Plantae
Clade: Tracheophytes
Clade: Angiosperms
Clade: Monocots
Order: Alismatales
Family: Zosteraceae
Genus: Phyllospadix
Species: P. scouleri
Binomial name
Phyllospadix scouleri

Genus/species Phyllospadix scouleri (Hooker)

 

Description: This flowering plant is most characteristic of the open rocky shores of the coast that are exposed to the full force of the waves, as on the west coast of Vancouver Island.  There it forms bright emerald-green beds on the rocks near extreme low-tide level.  The plants are relatively short, usually not more than a metre in length, and the leaves are 20-32 mm. wide.  Short basal flowering stems are produced, which are 5-8 cm. long.

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

Pacific Coast Distribution:  Alaska to Mexico.

Robert Scagel, 1972

 
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 8 2009- Ryan Murphy

Diodora aspera: Keyhole limpet– The Race Rocks Taxonomy

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Keyhole limpets have a distinctive mantle-covering response when they are approached by a predatory sea star such as Pycnopodia.sp

Physical Description:

it has a small oval opening at the top of its short, conical shell. Although the keyhole limpet superficially resembles “true” limpets, its soft anatomy reveals an important difference. True limpets draw water into their mantle cavity on the left side, pass it over a single gill and discharge it on the right side. Keyhole limpets draw water in both sides, where it flows over paired gills before flowing out through the “keyhole” aperture at the peak of the shell. Size: Length is about 75 mm


Global distribution:
The Rough Keyhole Limpet can be found anywhere in coastal regions from Afognak, Alaska, to Baja California. It is found primarily in low intertidal areas, and has been seen up to 40 feet subtidally in the south (Morris et al. 1980).
Habitat:
The Keyhole Limpet clings tenaciously on and under large rocks in the sub to low intertidal. They can also be found on large kelp stipes. Their strong foot allows them to thrive in some intertidal areas where turbulent wave action is prevalent.

Domain Eukarya
Kingdom Animalia
Phylum Mollusca
Class Gastropoda
SubClass Prosobranchia
Order Archaeogastropoda
Family Fissurellidae
Genus Diodora
Species aspera
Common Name: Key-hole limpet
Feeding: This particular limpet is an omnivorous grazer. It feeds by scraping rocks with its radula. Various bryozoans are its food of choice, but it also consumes algae, as well as some sponge species.
Predators:
Sea stars, the limpet responds by raising its mantle up over the outside of its shell, a behavior that may prevent the sea star from gripping the shell surface.
Reproduction:
Keyhole limpets have separate sexes, and sexually ripe individuals can be found during any season of the year. Eggs and sperm are released into the water in mass quantities and larval settlement ensues.
One interesting Fact: Recent studies suggest that this animal’s unique apical opening is not only associated with sanitation, but also plays an important role in inducing passive flow through the mantle cavity. In studies where the keyhole of Diodora aspera was blocked (either naturally or experimentally) no evidence of damage to the mantle cavity or associated organs was found. In these experimental trials, water entered ventro-posteriorly with respect to the gill tips, and exited over the head region (near the anus). The apical opening proved unnecessary as a means of waste removal. Researchers did find however, that the keyhole played an essential role in allowing water to flow passively through the mantle cavity. Thus, it is thought that this function of the apical opening may have been just as significant as its role in sanitation in terms of limpet evolution

References:
Wylam, B. 2001. “Diodora aspera” (On-line), Animal Diversity Web. http://animaldiversity.ummz.umich.edu/site/accounts/information/
Diodora_aspera.html.

Guide of Marine Invertebrates.- Alaska to Baja California
Daniel W. Gotshall.- Sea Challenges.
Monte Rey – California, USA 1994

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 2005-  Claudia (PC yr 32)

Hildenbrandia ruber : The Race Rocks Taxonomy

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hildenbrandia

Hildenbrandia ruber covering rocks in a tide pool. All photos by Ryan Murphy

Phylum: Rhodophyta
Class: Florideophyceae
Order: Hildenbrabdiales
Family: Hildenbrandiaceae
Genus and species: Hildenbrandia ruber (Sommerf)

Description: This plant exists as a thin encrusting layer on rock substrata. Its common name “rust spot” aptly describes this plants appearance.
Habitat: On rocks in the middle and upper intertidal zone, and on ship hulls.
Distribution: Most of Pacific Northwest

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

 

Limiting Factors and the Ecological Niche

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BACKGROUND:
normalcurveEnvironmental abiotic and biotic factors can also be termed “Limiting Factors.“ They are limiting in that they tend to select only for those organisms which have the best tolerance, or adaptation to the factor. At different times of the year, some abiotic factors take on more importance than others. Water is certainly not a limiting factor at Race Rocks in the months of December and January compared to the dry months of July and August. In this assignment, we will examine data records and determine what other factors are variable in their importance in various times of the year. This assignment is paired with the assignment on Abiotic Factors

Objectives:

1. Present an argument for what you consider to be the most important abiotic factor in determining the distributions of organisms at Race Rocks , and contrast this with what you consider to be the most important factor in determining the distribution of organisms where you live.

2. Use the following terms to explain with graphs, examples of the concept of Limiting Factors.

  • Euryhaline and Stenohaline
  • Eurythermal and Stenothermal

3. Describe how Natural Selection of species occurs as the result of Limiting Factors.

4. Demonstrate how Limiting Factors of the environment determine and define the ecological niche of an organism.

5. Produce a graph demonstrating the Ecological Niche of an organism.

6. Discuss how our built up environments with cats, lawns, and other introduced species limit the ecological niches available and thus impact negatively on Biodiversity.

PROCEDURE:

1.Introduction: Examine this graph representing the Normal Curve or a Bell Curve of the level of population of a species, in a certain area, or the density. If you think of the blue line here representing the number of individuals of animals or plants in a population, which exist in an environment with abiotic conditions favoring those at the central value of 0, then you can see that there is actually more positive selection for the central area being exerted than for either of the extremes. Species evolve in much this way. Those having the right amount of insulation, the right amount of ability to survive dessication or drying up, the right abilities to survive in a certain salinity or level of dissolved oxygen, or the right ability to tolerate a high level of wind in their environment, are the ones who are more successful in reproducing and thus their traits get passed along to more offspring. So the X-axis can represent the abiotic variables in an environment.

2. Correlate the month of occurrence of a species and the population levels for that month.

3. We can see from the assignment on abiotic factors, that there may be dozens of such graphs you could make for any organism.musshand At Race Rocks, we have two species of the molluscs called mussels. They are Mytilus californianus and Mytilus trossulus . Visualize the x-axis above being a scale of temperature, for a marine animal such as a mussel, lets say the ideal temperature for mussels is 10 degrees C. Draw a similar graph with 10 in place of the 0 . Show the scale going up and down from 10. Lets say that the Mytilus californianus mussels cannot reproduce at a temperature higher than 12 degrees nor lower than 8 degrees C, so the blue line tapers down and ends at 8 degrees C.
4. Now plot another graph on the same scale, This one is for the other local mussel, Mytilus trossulus. musselpool4It lives in the intermediate level tidepools and can survive in water up to 16 degrees and down to 4 degrees. In the sample above we say that the M.californianus is a Stenothermal ( narrow range of tolerance to heat) animal, whereas the M.trossulus is a Eurythermal (wide range of tolerance to heat) organism
5. Next we will do a similar plot for salinity. Here 30 parts per thousand for salinity becomes the central measurement and above and below that amount make the rest of the scale. M.Californianus prefers to live in water that is 27 parts per thousand. But it can live in up to 30 or down to 25. M.trossulus also prefers 27 parts per thousand, but can live in water that ranges from 32 down to 22 parts per thousand. Now if we combine the same prefixes: Eury and Steno,with the word haline, we will get a word that describes the organisms. So now you have two new words that help describe the variation the same abiotic factor can have on two closely related species.
6. Natural Selection which can lead to the evolution of separate species, is often determined by the way an organism is able to tolerate variations in the abiotic factors of it’s environment.variabilityJust when that seemed so straightforward, we have to recognize that selection pressure may affect the same species group in different ways. Two species of mussel may on the other hand prefer different ranges of temperature or salinty instead of the 10 degrees. The picture B could represent that situation. What would the skewed distribution in C therefore represent in terms of selective pressures on the population?

mus7. The Ecological Niche is defined by limiting abiotic and biotic factors: In this assignment, we deal with the problem of defining what are the ideal conditions for an organism’s existence. At Race Rocks, the position on a shoreline within a few centimeters can determine survival of an organism. Use these references to find out about how you can model an ecological niche of an organism. Choose an organism in your own ecosystem and produce a graph representing it’s ecological niche.

 

malesparrow8.This now brings us to a classical study in Adaptation which was done over a century ago! This study has provided the data for many studies on limiting factors of the environment. However, be careful about jumping to conclusions! This study points out the difficulties in attributing what may at first seem to be a simple cause and effect relationship. See Bumpus’ Sparrows

9. Extension Materials: Central Tendency and Variability

Also, you may wish to take this opportunity to get into an exercise on Standard Deviation. To draw such a curve as the Normal Curve at the top of the page, one needs to specify two parameters, the mean and the standard deviation.  The graph has a mean of zero and a standard deviation of 1, i.e., (m=0, s=1).  A Normal distribution with a mean of zero and a standard deviation of 1 is also known as the Standard Normal Distribution.

Heptacarpus tenuissimus: The Race Rocks Taxonomy

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A very small shrimp, not often noticed but probably common at Race Rocks.
Domain Eukarya
Kingdom Animalia
Phylum Arthropoda
Class Malacostraca
Order Decapoda
Family
Genus Heptacarpus
Species tenuissimus
Common Name:
slender coastal shrimp

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- 

Elassochirus tenuimanus The Race Rocks Taxonomy

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Domain Eukarya
Kingdom Animalia
Phylum Arthroppoda
Class Malacostraca
Order Decapoda
Family Paguridae
Genus Elassochirus
Species tenuimanus
Common Name: Wide-hand hermit crab

In this video, Elassochirus has been disturbed from eating a limpet (Collisella instabilis). It recovers and returns to eating. Note the colouration of the appendages of the hermit crab. Also note that one arm is much wider than the other. The Collisella which normally has a pale shell, is encrusted with the pink algae Lithothamnion.

General Description:
Named as wide-hand, this species hermit crab has a large and flattened right side of chela, carpus and propodus more than its left side. The right cheliped has a wider carpus than it is long. The walking legs have colours of white, reddish brown and purplish-blue on its merus.

Size:
The exterior length is up to 42 mm (1.6 inches).

Natural History, Habitat and geographical and depth range:
Mud, sand, shell bottoms, and especially rocks. The depth range is intertidal (infrequently) to 388 m (1272 feet). For the geographical range, the hermit crab lives in Bering Sea and Aleutian Islands, from Alaska to Washington, and the northwestern Pacific.
Ovigerous females in Washington usually appear from August to May.  Larvae produce from March to May and Planktonic are in last months of the year.

Behavior
When the animal retreats inside, the right claw is used to block the access to the shell itself. The crab bents this claw beneath the body while walking.

References:
– Pacific Coast Crab and Shrimps, Gregory C. Jensen; Sea Challengers Monterey, California, 1995.

– Marine Invertebrate of the Pacific Northwest, Eugene N. Kozloff; University of Washington Press, Seattle and London, 1996.

http://people.wwc.edu/staff/cowlda/KeyToSpecies/Arthropoda/Crustacea/Malacostraca/Eumalacostraca/
Eucarida/Decapoda/Anomura/Family_Paguridae/Elassochirus_tenuimanus.html