Category Archives: Archived Video

Neomolgus littoralis: the red velvet mite

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The video above was taken by Peg 15 on the North Shore of Great Race Rock where the students of a biology class were doing an intertidal transect. We often find Neomolgus at this elevation, and it is one of the few invertebrates inhabiting the top range of the spray zone.

Neomolgus is a tiny mite looking like a little red dot moving across rocks or other hard surfaces. Its diameter is 3mm. Mites are like spiders and ticks in that they have four pairs of legs. At Race Rocks, it is especially common among the bare rocks out on the North West corner by peg15.

Neomolgus has a large distribution in the northern hemisphere. It moves very actively and responds very negatively to the approach of a human finger. It uses its long snout for piercing small flies and sucking their juices.

Links:http://www.beachwatchers.wsu.edu/ezidweb/neomol01.htm

Kozlof : SeashoreLife of the Northern Pacific Coast.

Lamb and Hanby, Marine Life of the Pacific Northwest, page 276

Domain Eukarya
Kingdom Animalia
Phylum Arthropoda
Class arachnida
Order Acari
Trombidiformes
Family Bdellidae
Genus Neomolgus
Species littoralis
Common Name:red velvet mite

 

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-  Rahilla (PC)

Tide Pool Abiotic factors

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In the high intertidal areas of Race Rocks, there are tidepools with wide fluctuations of abiotic factors. The organisms inhabiting these pools are well adapted to these extremes. Garry talks to a biology class about some of the variables influencing these high tide pools, and the flagellated green algae living within them.

Apodichtys flavidus: The Race Rocks Taxonomy

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These images were taken on the remote camera 5 shows a Pigeon Guillemot prior to feeding a Penpoint gunnel to chicks.During the months of May and June, the Pigeon Guillemots (Cepphus columba) are constantly diving off the north side of Great Race Rock and bringing up penpoint gunnels for their young. They nest under loose rock on several locations arounf the island. They are very cautious about going to their nest burrow where they may be seen by predators,

PUGET SOUND/ Strait of Juan de Fuca SPECIES

Apodichthys flavidus Penpoint Gunnel

Pholis clemensi Longfin Gunnel

Pholis laeta Crescent Gunnel

Pholis ornata Saddleback Gunnel

Pholis schultzi Red Gunnel

Xererpes fucorum Rockweed Gunnel

PENPOINT GUNNEL

This is a family of littoral fishes of the northern Pacific and northern Atlantic.They are typically found hiding under rocks and logs or in tidepools at low tide.The longest gunnel , at maximum of 46 cm,is the Penpoint Gunnel.Most gunnels feed on small crustaceans and molluscs.There are about 14 species, six are found here. Although secretive , this family is common in Puget Sound. This fish is not important commercially and is not considered threatened.This species can breath air when out of water.

PHYSICAL DESCRIPTION: Body elongate and compressed (eel-like body with no pelvic fins). Contains only flexible spines ,may have a dark streak that runs through the eye from top of head downward . Eye round, its diameter about one fifth the into length length of head. It may have small dark spots along the sides.Distance from snout to anal origin greater than half of body length.Maximum length is 1.5 feet.10 large melanophores along dorsal surface of gut and anus, melanophores can be also along postanal and dorsal near caudal region,ventral surface of gut has a row of small melanophores.Colour very variable depending upon diet as well as environment, from green through brown to red, the green colour from pigments dispersed through skin, the red in special pigment cells, the brown in combination (Hart 1973).Teeth are sharp,pointed, apparent in post-larvae.

Dorsal fin KC-XCIV (Miller and Lea 1972).

Anal fin I,36-42 (Miller and Lea 1972); I,38-42 (Hart 1973).

Pectoral fin 15-16 (Hart 1973).

Mouth Terminal,small,with thick lips (Hart 1973).

Verebrae 96-101 (Miller and Lea 1972)

DISTRIBUTION: Southern California to southeast Alaska and Kodiak Island.In British Columbia on both coasts of Vancouver Island, the Strait of Georgia .Common in Burrard Inlet in September.Queen Charlotte Islands (Hart 1973). In costal or bay water blending with vegetation such as Sargassum spp.,Ulva spp., and Zostera spp.,settling on the bottom at ca. mm TL (Wilkie 1966).Pelagic,along coastal waters and bays. Horseshoe Cove and vicinity of Portero Power Plant on San Francisco Bay,Marconi Cove of Tomales Bay.

REPRODUCTION: Spawing occurs from January to March.The egg mass is coiled around by one or both parents.The incubation period is about two and two a half months.Newly hatched larvae average about 13mm, and the body is transparent and positively phototactic (Wilkie 1966).The age of maturity of the penpoint gunnel has not be documented in the literature.Growth appears to be rapid during the first year from 20 to 40 milimeters in April and May to 100 to 120 millimeters by the end of summer.

REFERENCES: J.L.Hart- Pacific Fishes of Canada(1973),Wilkie (1966)

 

 

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 2003- Miroslav Lestanin

 

Fabia subquadrata: The Pea Crab — The Race Rocks Taxonomy

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Jeremias, Carmen and Felix remove a pea crab from the mantle of a California Mussel.
At Race Rocks there are many large mussels; (up to 30 cm) with such parasite inside.

 

Domain Eukarya
Kingdom Animalia
Phylum Arthropoda
Class Crustacea
Order Decapoda
Family Pinnotheridae
Genus Fabia
Species subquadrata
Common Name:Pea crab

Brief Definition

Pea/Mussel crabs are tiny creatures that live as symbionts, on or in the bodies of other invertebrates (bivalves)

Size

As their common name implies, Pea crabs are small creatures. The female pea crabs are distinctively larger than the male crabs, reachimg a size of 22mm (0.8in). The males however reach a size of 7.3mm (0.3in).

Habitat

Pea crabs occupy 2 different niches during their lifetime. Prior to and after their mating season, the adult female lives in a host. Host species include:

California mussels ( Mytilus californianus )

horse mussels ( Modiolus modiolus ).

Mytilus edulis

As well as other species of bivalves including scallops, oysters, cockles and clams.

The juvenile crabs also occupy a host before they become mature.

Range

These crabs live in mainly the northern hemisphere waters.

Including eastern and western U.S.(Akutan Pass, in the waters of Alaska to Ensenada.), Europe, Argentina and British Columbia, Canada.

It is found in 1 to 3% of California mussels along the central California coast, and 18% of mussels along Vancouver Island, BC, Canada.

Adaptation

Mussel crabs live in specific hosts because each crab responds positively to only certain chemicals that their hosts emit. In this way, they are able to infest the hosts that have the right conditions for them to survive. While in the host, these crabs do not posses an exokeleton. This is beacause the hosts provide them with protection against predators and other harmful external factors. However, when they leave their host to mate in the planktonic environment, the adult crabs grow an exoskeleton to protect their membranous carapace. These crabs also posses 10 legs, of which 2 of them develop into large and powerful claws to help fend off predators when exposed in the plankton, and to also help in the grasping of food.

Relationship with Host

The relationship that exists between the mussel crab and the bivalve is a symbiotic one. The advantage of this relationship is that the crab is protected while it scavenges the necessary nutrients needed by it, in the host. The crab however at times robs its host of a large mount of food and it also feeds off the protective mucus layers that cover the host’s tender tissues.This results in the mussel’s gills been injured. When this occurs the relationship becomes a parasitic one as the crab benefits while the host is affected negatively. Hence they are classified as parasites.

Precautions are taken when animals such as Mya arenaria, Placopecten magellanicus, Argopecten irradians and oysters are sold as to not have a pea crab inside it.

Reproduction and Lifecycle

The pea crabs’ life cycle has two distinct stages. These two stages are so different that in fact they were classified into two different genera.

The first stage comprises of the large, adult females that have soft membranous crapaces. These adults occupy a host each and they produce larvae that mature into the second stage. In the second stage, the offspring (larvae) of the female (that she had produced inside her host) grow up into adults of both sexes.Having reached maturity, they leave their hosts and join swarms in the water to mate. At this stage the pea crabs look more ‘traditional’. They have hard shells, strong legs (for swimming) and at the front of the carapace they have thick hair. Upon completion of mating, the female returns to her host. For a period of 21-25 weeks, she goes through 5 molts before reaching maturity. The female can inhabit here for up to a year, producing larvae from eggs that where fertilised by sperm from her single mating and then the cycle begins again. The mating takes place in late May.

Note: the male after mating dies.

References

Source 1: Pacific Coast Crabs and Shrimps by Gregory.C. Jensen, Ph.D

Source 2: Port Townsend Marine Science Center. Marine & Natural History Exihibits

Source 3: http://www.ptmsc.org/html/peacrabs.html

Source 4: http://life.bio.sunysb.edu/~jmatth/Science.htm

Source 5: http://www.pac.dfo-mpo.gc.ca/sci/shelldis/pages/pcbmu_e.htm

Source 6: http://www.indian-ocean.org/bioinformatics/crabs/crabs/tex1.html

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 2003-  Michelle(PC)

Fishing Flashers Entanglement in Sea lions

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September, 2003 : This past few months we have seen three California and Northern Sea lions with fishing flashers hanging from their mouths. These animals pursue fishing lures , probably especially when live bait is used. They swallow the bait, and take down the meter plus length of leader line before the flasher comes to their mouth. The individuals will be seen for several days trailing these flashers. It is not known whether they eventually shed the flasher or whether this leads to an untimely death. Although they can pick up a flasher in waters at some distance from their haulouts, it certainly makes sense to restrict fishing activity when marine mammals are in the vicinity of a fishing vessel.

Slash Recovered a Year Later

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This Elephant Seal was struck by a motor boat at Race Rocks in January of 2003. Fortunately he has recovered well as can be seen her in two videos taken by Mike Slater in July and August ,2003. See the footage taken of his original injuries here.

2009: We have called this elephant seal “SLASH” and he now has his own page here

MPA Guardian Carol Slater’s comments on these animals in the Daily log of Jan19, Feb 11, Feb13, Feb 14 and Mar 1, 2003

Helicopter Landing Kills Gulls

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Human disruption in a seabird nesting colony at certain times of the year can have disastrous consequences for young birds. The territorial instinct is so strong that young birds leaving the envelope of their nesting territory get attacked by other adults of nearby territories. This incident was precipitated when a Canadian Coast Guard helicopter made an unscheduled landing at the island in August 2003. Normally they do not come to the island in the sensitive period, this time a mistake was made!

The Giant Pacific Octopus

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Giant PacificOctopus 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 recentlyin June 2002, became the subject of a webcast and an impromptu dissection on the shore.

 

Underwater Transect at Race Rocks

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The most difficult transects to do at Race Rocks Ecological reserve are those underwater. Through the years we have done a number of these, mostly in training sessions with the Pearson College Divers.  We experimented with various types of spools for laying out a line, types of weighted line, measuring tape, quadrat sizes, types of underwater paper on clipboards, types of pencils or writing devices  etc.  The best arrangement was using a 30- 50 metre long tape which could be attached to the peg on shore  and then taken out by the diver in a predetermined compass direction. The biggest problem other than the narrow window to get the work done was always the kelp cover, making the process very difficult in the later part of the year when the Nereocystis, (bull kelp) cover would make it impossible to access some areas.   The divers working in pairs would then proceed along one side of the line producing a record of the belt transect.  

Laura Verhegge and students of Pearson College doing an underwater transect off peg #1 at Race Rocks.

 


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Return to the Contents page for Environmental modelling with Transects..

Limnodromus griseus: Short-billed Dowitcher–The Race Rocks Taxonomy

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Short -Billed Dowitchers, photo by Riley Strother, April 20 2017

This juvenile short-billed Dowitcher was seen up near the tower in August 18 2009. It was very tame and quite unconcerned with the local humans. Image by Ian Perry.

The same juvenile, (Aug 18/ 09) , shown above. Images by G.Fletcher
Dowitcher probing for invertebrates Note the Halosaccion band of the intertidal zone where it is feeding rear view- note buff colored underparts side view- note dark eye.
Eukarya
Kingdom Animalia
Phylum Chordata
Subphylum Vertebrata
Class Aves
Order Charadriiformes
Family Scolopacidae
Genus Limnodromus
Species griseus
Common Name: Short Billed Dowitcher

The Short-billed Dowitcher breeds in Northern Canada. It winters in South America.
It occurs rarely and solitary at Race Rocks where it stops on migration. Short-billed Dowitchers normally are birds of mudflats along the Pacific Coast. One individual bird was filmed on May 1 2003 (above)as it probed for food among the barnacles and algae of the Halosaccion zone at Race Rocks.

In the photo to the right from September 2005, another dowitcher roamed through the area near the base of the rock on the East side. So presumably we have pictures of the stopover going North and South!

Compare with the size of a gull in this Link to a post showing Dowitchers at Race Rocks-April 20 , 2017

This video shows the Short-billed Dowitcher (Limnodromus griseus) in the intertidal zone to the East of the docks at Race Rocks. Note the “sewing machine ” action as it probes for food. The biology class watched this bird on May1/03 before starting on an intertidal transect in the same area. The coloration was noticeably buff-colored when compared to other shore birds. This individual was very fearless, even returning to feed briefly nearby after we had laid down our transect. This is normally a bird of the Pacific Coast mudflats.

 

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. May 2003– Garry Fletcher/strong>