Tag Archives: limpet

March 12 – Sunny Census Thursday

Posted on by

Sunny
Wind: 0-13 knots SW in the morning, NE from mid morning to afternoon and SW in the evening
Air Temperature: Low 9.9°C, High 13.2°C
Ocean Temperature: 9.0°C

Three Pearson students came to Race Rocks this morning. Karen, Sunny and Hanne joined Martin, who has been here since Monday.

The students did some work this afternoon: sweeping all 99 steps of the lighthouse and continuing the process of stowing the chopped wood in all the nooks and crannies of the buildings, to be used next winter to heat the main house.

There was DND blasting happening in the morning and early afternoon on Bentinck Island, less than 1km away from the ecological reserve.

Today’s high temperature of 13.2°C, as measured at the ground weather station, was the highest recorded since 2006, when the weather station was installed. A high of 14°C was recorded by the instruments at the top of the lighthouse.

Three eco tour boats visited the reserve. One boat came very close to a group of sea lions swimming and others hauled out on the South Islands.

The low tide of 1.1m at 13:52, exposed lots of species from the low tide zone into the air. The shore and tidal pools were full of life: mussels, barnacles, limpets and lots of other flora and fauna of the sea. The oystercatchers and shore birds were having a feast.

There were no small birds perching birds seen today. There are usually a few fox, sparrows, savannah sparrows and occasionally juncos and robins zipping around the island.

Here are the results from today’s Megafauna Census:
Elephant Seal: 1
Steller Sea Lion: 54
California Sea Lion: 43
Harbour Seal: 52
Bald Eagle: 9
Great Blue Heron: 1
Crow: 1
Oystercatcher: 4
Double Crested Cormorant: 12
Brandt’s Cormorant: 21
Gull: 247
Canada Goose: 14
Pigeon Guillemot: 9
Harlequin Duck: 13
Surfbird: 3
Black Turnstone: 10
Rock Sandpiper: 2

Diodora aspera: Keyhole limpet– The Race Rocks Taxonomy

Posted on by

 

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)

Notoacmea scutum : Checkered Limpet -The Race Rocks Taxonomy

Posted on by
Physical Description:
The average size of this species is 4-6 cm in length (shell) and 3-4 cm wide, with a low profile and rounded apex found forward of its center. The shell of this species is relatively smooth, conical or oval in shape, sculptured with coarse, flat-topped ridges. The color of the surface varies, though externally brown or green with radiating with white spots or lines.Habitat:
The Notoacmea scutum are found “between the high and low-tide lines” on smooth surfaces, usually rocks, while showing a “tidal rhythm of activity” which occurs more often at night.
Reproduction:
Spawning occurs, most abundantly, from autumn to spring, but can happen throughout the entire year. Spawning results in the external fertilization via males releasing sperm into the females, who then release their fertilized eggs into the flowing water.

Range (global):
Research has been shown that the Notoacmea scutum species can be found in the Aleutian Islands and Mexico and from Alaska to Baja, California.

Domain Eukarya
Kingdom Animalia
Phylum Mollusca
Class Gastropoda
Sub class Prosobranchia
Order Archaeogastropoda
Family Acmaeidae
Genus Notoacmea
Species scutum
Common Name: Checkered Limpet

Reference:

www.nmarinelife.com/htmlswimmers/n_scutum.html
www.nbl.noaa.gov/(zeajfizhdjfdsf45hn4n3k55)/itis.aspx?tsn=69716
http://academic.evergreen.edu/t/thuesene/animalia/mollusca/gastropoda/notoacmea/scutum.html
www.people.wwc.edu/staff/cowlda/keytospecies/mollusca/gastropoda/prosobranchia/order_patellogastropoda/family_lottiidae/tectura_scutum.html
¬ Intertidal Invertebrates of California
¬ Reproduction and Development of Marine Invertebrates of the Northern Pacific Coast Data and Methods for the Study of Eggs, Embryos, and Larvae

Other Members of the Phylum Mollusca 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 for this file was done by Shaterra Redd PC student year 32 . 2005

 

Lottia instabilis: The Race Rocks taxonomy

Posted on by

The unstable limpet measuring approximately 3-4 cm is brown on its exterior and interior. It’s saddle-shaped when turned on it edge. Its habitat at Race Rocks is on the stipes (stems) of Pterygophora always growing subtidally.Thus the uneven margin underneath. It’s range is from Alaska to California

Joel Julius PC year 31 , with the shell of the unstable limpet.

Kingdom: Animalia
Phylum: Mollusca
Class: Gastropoda
(unranked): clade Patellogastropoda
Superfamily: Lottioidea
Family: Lottiidae
Genus: Lottia
Species: L.Instabilis

 

 

 

 

 
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.  2005-Joel Julius PC year 31.

Acmaea mitra: whitecap limpet– The Race Rocks taxonomy

Posted on by
 
Introduction:The White Cap Limpet, very common on the British Columbia coast, is usually found on the lower zones as compared to the intertidal zones of other limpets. White cap limpets shells are white in colour amd rather thick in nature. The animal extends from 19-44cm (0.75-1.75″) in size.

The limpet, however, can only be seen as white after it is dead. When alive, it usually is covered by a pinkish coralline algae, Lithothamniom sp. which is also its main source of food. This forms an excellent comouflage. It’s predators include sea stars.

References: now defunct
http://web.mit.edu/corrina/tpool/limpets.html#whitecap
http://www.gastropods.com/shell_pages/m/Shell_Acmaea_mitra.html
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. January2002-Amardeep Kaur (PC yr. 27)

Predation by the Black Oystercatcher….1999

Posted on by

In September of 1999, the students of the Environmental Systems Class collected the shells in the midden surrounding the nest of a pair of Black OysterCatchers at Race Rocks, They analysed the size, species diversity, and species frequency of the shells. The following data and charts are presented in order to provide information about the role of this seabird in the intertidal ecology of Race Rocks.

Numbers of Shells Collected Near Black Oyster Catcher’s Nest
    Limpets: Mask, Shield, and Plate 350    
    Limpets: Whitecap 70    
    Limpets: Fenestrate 19    
    Limpets: Rough Keyhole 2    
    Chitons: Black Katy 73    
    Chitons: Mossy 13    
    Chitons: Lined Red 7    
    California Mussels 342    
    Ribbed Whelk 5    
    Amphisia Snail 1    
         

Average Size of the Oyster Catcher’s Food california mussels –5.2875 cm plate,mask,shield limpets–3 cm whitecap limpets 5.2875 cm 3 cm 2.985 cm Size of Oyster Catcher’s Food: Raw Data, in cm

california mussels plate, mask and shield limpets white cap limpets
3 2 1.7
4 2.2 2.1
4.2 2.5 2.3
4.5 2.8 2.4
4.6 2.8 2.5
4.6 2.8 2.6
4.7 3 2.7
5.2 3 2.8
5.25 3.1 2.9
5.3 3.2 3
5.5 3.4 3.2
5.5 3.4 3.2
5.5 3.5 3.2
5.8 3.5 3.2
6. 3.5 3.3
6.5 3.5 3.6
6.6 3.6 3.7
7.5 3.8 3.8
7.8 3.8 3.8
gfcarolshell

Garry Fletcher and Ecoguardian Carol Slater examining sorted shells of black oystercatcher prey from on midden.

Image1 Image3