Category Archives: ER Warden Report

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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Installation of the Remotely Operated Camera 5 at Race Rocks

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This remote controlled camera gives a full 340 degrees view of the land and surrounding waters of Great Race Rocks. The panoramic view with zoom capabilities can be controlled by the viewer.

Photos for this page by G.Fletcher

Be sure to use the manual focus when needed, and we apologize if occasionally the housing is covered with salt spray making viewing difficult, as it is not easy to keep it clean in this exposed location.

The original cam 5 was a SONY camera provided by Apple. This was replaced in 2010 with a canon VBC60, available from Nuspectra.

We have had collaboration from viewers in capturing pictures from this camera. See this example.

Elephant seal mating

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Two elephant seals haul out on the lawn and provide evidence of mating behaviour.  The female has a large cut around her neck indicating an old injury. (Scarlet)

On January 22, 2004 Mike and Carol Slater moved camera 3 over to their house in order to keep track of the male elephant seal, Mirounga angustirostris who has been hauled out on Great Race Rocks recently. They took these images right outside their house. He is the same one (Slash) who was injured a year ago.. See the video footage from January 03, and from August 03

This was the first time an adult female had come up to join him on the lawn. That afternoon there was considerable maneuvering for reproductive purposes.

It turns out that the female has also had an extensive injury. This deep cut, now healing over has probably been caused by a fish net or rope. We have not observed this female before at Race Rocks. She may have been hauled up on the Middle island where they lie on the flat top part and are not very visible from a boat. ( Later, Pam Birley gave this female the name of Scarlet
In 2009, we believe this same female elephant seal has again shown up on Middle Island

 

 

Bald Eagle Predation on Birds at Race Rocks

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We received the pictures for this file attached to an e-mail from Pam Birley, a regular observer from England on our cameras. She saved these images from our remote camera so we have quoted her e-mail here describing the events as they unfolded…….

. ” On January 22/04, it was a peaceful scene on the cliff with a large group of cormorants and a grazing goose….when suddenly a young bald eagle swooped down and made a meal of one of the birds….

 

Note that the cormorants were swimming out beyond their perch at this point as the eagle stands on his prey . …..A passing seal kept popping up to see what was going on….

 

…….and when the eagle had finished its meal it flew off, leaving the rest of the carcas for the seagulls to finish off.. Quite a little drama. What a fantastic site – always something of interest”

 

….Pam goes on to say…” Do you know where the elephant seal is (we call him Big Guy) – I can hear him but can’t find him on the cam – he was under that rock for about a week. I belong to Whale Watchers Group on Yahoo, most of us being addicts of Orca-Live.com during the summer and we have been pasting some RR captures on that site. We do give credit to you of course and we are spreading the word about your excellent website. Thank you so much !!! .”….

(ed. note) : Well thank you Pam! We really value your observation and quick action in recording these scenes and sending them along to us as an e-mail attachment. One of our Japanese students has suggested the name “Debu” (Fatty in Japanese) for the elephant seal that spends much of his time up on the main island. If you can hear him but not see him, he is hauled out just out of range of the camera on the North side of the house. He likes the soft long grass of one of the lawns. See the marine mammals archives for several videos of this elephant seal who was badly injured last year.

 

The Ecological Niche of the Black Oystercatcher

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blkoyst

 

OBJECTIVES: After doing this field lab, students will be able to:
1. Quantify various aspects of the ecological niche of a seabird.
2. Do statistical comparisons using several sets of data collected in the field.
3. Demonstrate an ability to plan the procedure of an investigation.

PROCEDURE:

1. We will collect the evidence for predation in the vicinity of one of the current years oystercatcher nests at Race Rocks Marine protected Area. A previous class may have already done this for you.

2. Your class will be asked to decide on how to analyze this evidence in order to quantify as many aspects as possible about the ecological niche of the oystercatcher. Write down your plans for the investigation before starting.

 3. Some hints for your planning:
— How can we estimate the biomass of the food species?

— Are all the prey species at the same trophic level?

— Can you tell something about energy expended by the bird in foraging by looking at the range of the mussel sizes?

— Just how much force (energy) does it take to extract at intertidal organism from it’s habitat?

— What can you contribute in terms of scientific information to this web page?

–Can we make a dichotomous key for identification of the prey species?

–How can we apply the concepts of pyramids of numbers, biomass , and energy with our information?

4. See the results of the Fall 1999 collection of shells from the midden of the oystercatchers. Use these results to help in the planning of this lab. It is assumed you will be able to build on these results and go further in the investigation.

5. –Use the diversity index calculator from the Maryland Sea Grant Extension Program at the Center of Marine Biotechnology to compare the two year’s data. Explain how we may use a diversity index such as this as a monitor of various environmental concerns. Be sure to see the page which describes the application of various indices of diversity.

Other possibilities:

— Use the “Odum” energy symbols to model the ecological Niche of the Black Oystercatcher.  (remember – there are NO oysters at Race Rocks!–Can some further media production be done on the oystercatchers?

Lontra canadensis: River Otter–The Race Rocks Taxonomy

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This otter has just caught a female kelp greenling. I consider this one of the best ecological pictures of the year at Race Rocks–Photo by Raisa Mirza Nov 4 2010

 

Location of River Otters at Race Rocks:

rmmar09lontra

Ryan took these photos of a rover otter in March 2009. The otter was coming out of the water on the East side of great Race.

The river otter Lontra canadensis, formerly Lutra canadensis, does not really have a natural habitat at Race Rocks because they usually inhabit small bays and inlets around Vancouver Island. However they have in the past made homes in holes under man-made paths and buildings at Race Rocks. They currently have made a home under a pile of rocks formed when the Coast Guard blasted the island to make a helicopter pad in the late seventies. Most of the other man-made habitats have been eliminated. Interesting local ecology/behaviour/adaptations:
The river otter is the largest of the family Mustiladae. It is a metre or more  in length with around a third of its body taken up by its tail. It has webbed feet and claws which are useful for use in the marine and terrestrial environments in which they live.
They have thick fur with long hairs enabling them to survive low temperatures. Ryan took this image of otter tracks at Race Rocks in December 2008 when we had a few weeks of cold weather and the snow actually stayed for a few days.

rmmar09lontra2

See more photos of Ryan Murphy on his Flickr website:

When diving in murky waters through which they cannot see properly they use their whiskers to detect prey. River otters are able to communicate with each other using chirps, whistles, chatters, chuckles, screams and growls.They are one of the most playful species constantly sliding on the ground, chasing each other.

Domain: Eukarya
Kingdom: Animalia
Phylum: Chordata
Class: Mammalia
Order: Carnivora
Family: Mustelidae
Subfamily: Lutrinae
Genus: Lontra
Species: canadensis pacifica (Schreber, 1977)
Common Name: River Otter

ottertrackThey have thick fur with long hairs enabling them to survive low temperatures. Ryan took this image of otter tracks at Race Rocks in December 2008 when we had a few weeks of cold weather and the snow actually stayed for a few days.

When diving in murky waters through which they cannot see properly they use their whiskers to detect prey. River otters are able to communicate with each other using chirps, whistles, chatters, chuckles, screams and growls.They are one of the most playful species constantly sliding on the ground, chasing each other.
Distribution elsewhere:
They occur along the Coast of Vancouver Island, often frequenting bays and estuaries and coastal marshes. The closest area where they are regularly found is Pedder Bay. There, we frequently see them on the college docks and on the southern shoreline. . Along streams and rivers in most of midwest and southwest USA (except Hawaii) they are common. Their population and density however varies with location. They can become a pest when they move onshore under buildings near the water.Their dead food and droppings create a disagreeable odor. They also can be vicious when cornered by humans or dogs.
Feeding particulars:
The river otter usually feeds on quite a variety of organisms, fish (herring mostly), seagulls (baby ones and eggs), crabs and shrimp. At Race Rocks they revert to birds and their eggs when the supply of herring is low. In July,1998 they wiped out the nests of black oyster catchers. They were also a threat to guillemot nests and were seen  digging away rocks to get to the nests. Whether the pigeon guillemot escaped or not is not known. Glaucous winged gull chicks are also victims. Man made habitat such as space under walkways and under buildings were removed in 2000 resulting in fewer occurrences of them on the islands.

Reproduction:

River otters usually mature at 2 years of age. Females usually get pregnant after three years. Males breed at around 5 years. See this slide show. They have litters of 1-6 with the usual amount being two or three children (kits)per mother. Female river otters have the ability to delay implantation. The young usually stay a year in the womb with a 60 day gestation period. They are quite helpless at birth and are blind. They open their eyes at around 3 weeks. The kits can take care of themselves at 5 or 6 months. However the family usually sticks together for an extra 2 months or until another litter is born.

The river otter breeds in March-April and give birth in late winter/early spring.
otterThis photo was taken in February, 2008
on the remote camera 5 by Pam Birley. The otter is seen coming out of the rock pile and moving over to the water. Below is a series of images taken by PB on February 29, 2008.

Other Posts on River Otters at Race Rock

Other posts on the Class Mammalia at Race Rocks

taxonomyiconReturn to the Race Rocks Taxonomy and Image File
pearsonlogo2_f2The Race Rocks taxonomy is a collaborative venture originally started with the Biology and Environmental Systems students of Lester Pearson College UWC. It now also has contributions added by Faculty, Staff, Volunteers and Observers on the remote control webcams. Garry Fletcher2003