Category Archives: Invertebrate video

Caprella laeviuscula: Caprellid shrimp– The Race Rocks Taxonomy

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We found these Caprellids at a depth of 20 metres attached to hydroids on a Balanus nubilus. They frequently dwell amongst hydroids. The size of this individual was 3mm. These individuals were photographed using a Motic Digital Microscope at 10X magnification. Note the response to stimulation by a dull probe.

In the picture below , the current meter float which was in the water for a year, came up covered with Caprellids. See this file on the Current meter:

Look closely to see these tiny skeleton shrimp clinging to bryozoans, hydroids or algae. Their body shape and color help the shrimp to blend into their background. Their bodies are long, cylindrical and range from pale brown and green to rose. Some species can quickly change color to blend into their backgrounds.

Skeleton shrimp look like, and sometimes are called, “praying mantises of the sea.” They have two pairs of legs attached to the front end of their bodies, with three pairs of legs at the back end. The front legs form powerful “claws” for defense, grooming and capturing food. The rear legs have strong claws that grasp and hold on to algae or other surfaces. They use their antennae for filter feeding and swimming.

Diet
diatoms (microscopic plants), detritus, filtered food particles, amphipods 
Size
to 1.5 inches (4 cm) long 
Range
low intertidal zone and subtidal waters in bays,

Conservation Notes

Skeleton shrimp are abundant and live in many habitats, including the deep sea. They play an important role in the ecosystem by eating up detritus and other food particles. 

Cool Facts

Shrimp, sea anemones and surf perch prey on skeleton shrimp. The females of some skeleton shrimp species kill the male after mating. 

Skeleton shrimp use their front legs for locomotion. To move, they grasp first with those front legs and then with their back legs, in inchworm fashion. They swim by rapidly bending and straightening their bodies. 

To grow, skeleton shrimp shed their old exoskeletons and form new, larger ones. They can mate only when the female is between new, hardened exoskeletons. After mating, the female deposits her eggs in a brood pouch formed from leaflike projections on the middle part of her body. Skeleton shrimp hatch directly into juvenile adults.

Source: Monterey Bay Aquarium:
Online Field Guide http://www.mbayaq.org/efc/living_species/default.asp?hOri=1&inhab=521

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. This file was originally started by Kevin Mwenda PC Yr 31

Caprella laeviuscla: Smooth skeleton shrimp

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Skeleton shrimp Caprella laeviuscula

 

We found these Caprellids at a depth of 20 metres attached to hydroids on a Balanus nubilus. They frequently dwell amongst hydroids. The size of this individual was 3mm. These individuals were photographed using a Motic Digital Microscope at 10X magnification. Note the response to stimulation when disturbed by a dull probe.

 

Garry and a Pearson College diver, stabilize the Institute of Ocean Sciences float before hauling it into the boat, This was at the end of one year of monitoring the tidal currents. From this process the Current Tables for Race Passage were developed by IOS.

This Post tells the story of the Current Meter Installation :

Look closely to see these tiny skeleton shrimp clinging to the bryozoans,The  shape and color help the shrimp to blend into their background. Their bodies are long, cylindrical and range from pale brown to green Some species can quickly change color to blend into their backgrounds.

Skeleton shrimp look like, and sometimes are called, “praying mantises of the sea.” They have two pairs of legs attached to the front end of their bodies, with three pairs of legs at the back end. The front legs form powerful “claws” for defense, grooming and capturing food. The rear legs have strong claws that grasp and hold on to algae or other surfaces. They use their antennae for filter feeding and swimming.

Diet
diatoms (microscopic plants), detritus, filtered food particles, amphipods
Size
to 1.5 inches (4 cm) long
Range
low intertidal zone and subtidal waters in bays,

Conservation Notes

Skeleton shrimp are abundant and live in many habitats, including the deep sea. They play an important role in the ecosystem by eating up detritus and other food particles.

Cool Facts

Shrimp, sea anemones and surf perch prey on skeleton shrimp. The females of some skeleton shrimp species kill the male after mating.

Skeleton shrimp use their front legs for locomotion. To move, they grasp first with those front legs and then with their back legs, in inchworm fashion. They swim by rapidly bending and straightening their bodies.

To grow, skeleton shrimp shed their old exoskeletons and form new, larger ones. They can mate only when the female is between new, hardened exoskeletons. After mating, the female deposits her eggs in a brood pouch formed from leaflike projections on the middle part of her body. Skeleton shrimp hatch directly into juvenile adults.

Source: Monterey Bay Aquarium:
Online Field Guide http://www.mbayaq.org/efc/living_species/default.asp?hOri=1&inhab=521

Also see:

http://www.nwmarinelife.com/htmlswimmers/c_laeviuscula.html

 

Domain Eukarya
Kingdom Animalia
Phylum Arthropoda
Subphylum Crustacea
Class Malacostraca
SubclassEumalacostraca
SuperorderPeracarida
Order Amphipoda
SuborderCaprellidea
InfraorderCaprellida
Family
Genus Caprella
Species laeviuscula
Common Name: Smooth skeleton shrimp

 

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 15 2005- Kevin Mwenda- Pearson College Year 31.

Rostanga pulchra :The Race Rocks Taxonomy

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It is almost always found in association with the red encrusting sponge Ophlitaspongia

Physical Description:
The red sea slug is oval and commonly recognized by its bright color either red, orangish, or scarlet. But it is not uncommon to find some lighter colored species. It matches the texture and color of the sponge that it feeds on. Its body usually measures from 10 to 30 millimeters long. The back of some of the specimens can be covered with sprinkling black specks that stand out more in lighter colors. Their dorsum is covered with caryophilletic tubercules, which gives it a velvety texture. Their unique feature is their rhinophores (organs of the smell) that have vertical perfoliations.
Global Distribution: The red sea slug is dispersed all throughout the Pacific coast of North America from Alaska south to Argentina and Chile. Concentrated especially in Vancouver Island (British Columbia) and Puertecitos (Baja California)
Habitat: They are usually found on the colored red siliceous sponges they feed on, that are encrusted under rocky edges.

Feeding:
Rostanga pulchra feeds on red sponges. Ophlitaspongia pennata, Esperiopsis originalis, Plocamia karykina, and also on Acarnus erithacus and Isociona lithophoenix. It can locate the food from distance by scent. It first removes the top part of the sponge to leave a shallow groove.

Predators:
The predaceous cephalaspidean Navanax intermis can be reppelled by the Rostanga by non-acid secretions.

Reproduction:
The red sea slug is oviparous. The color of the eggs is similar to the color of the slug as well as the one of the sponge. It breads year round. The cylindrical eggs strands (2,000 to 13,000 egg capsules) are laid in a spiral pattern on the sponge they feed upon. The egg development is influenced by temperature: the warmer the shorter the development is. The eggs then develop into a larvae called veliger and drifts as plankton in the sea. The larvae will then settle and metamorphose in a suitable environment.
One interesting Fact: Like all nutribranchs, the Rostanga pulchra is hermaphrodite, which means that it has both female and male sex organs, thus their chances of meeting a potential mating partner increase. But self fertilization remains very rare.

References:
<oceanlink.island.net/oinfo/nudibranch/nudibranch.html>
<http://www.seaslugforum.net/display.cfm?id=9337>
<slugsite.us/bow/nudwk379.htm >
<www.calacademy.org/research/ izg/SFBay2K/Rostanga%20pulchra.htm>
<people.wwc.edu/…/Mollusca/GastropodaOpisthobranchia/Nudibranchia/Doridacea/Rostanga_pulchra.htm>
<www.racerocks.com/racerock/ eco/taxalab/2005/rostangap/rostangap.htm>
<www.metridium.com/monterey/nudibranchs/rostanga

<em><strong>Other<a href=”https://www.racerocks.ca/category/species/class-mollusca/”> Members of thePhylum Mollusca</a> at Race Rocks.</strong></em>

<table>

<tbody>

<tr>

<td><a href=”https://www.racerocks.ca/race-rocks-animals-plants/taxonomy-image-gallery/”><img class=” wp-image-17530 alignleft” src=”https://www.racerocks.ca/wp-content/uploads/2014/11/taxonomyicon-300×91.jpg” alt=”taxonomyicon” width=”201″ height=”68″></a><a href=”https://www.racerocks.ca/race-rocks-animals-plants/taxonomy-image-gallery/”><strong>Return to the Race Rocks Taxonomy

and Image File</strong></a></td>

</tr>

<tr>

<td><a href=”http://pearsoncollege.ca/” target=”_blank”><img class=”alignleft wp-image-5251″ src=”https://www.racerocks.ca/wp-content/uploads/2013/05/pearsonlogo2_f2.jpg” alt=”pearsonlogo2_f2″ width=”121″ height=”73″></a><strong>The Race Rocks taxonomy is a collaborative venture originally started with the Biology and Environmental Systems students of <a href=”http://pearsoncollege.ca/” target=”_blank”>Lester Pearson College UWC</a>. </strong><strong>It now also has contributions added by Faculty, Staff, Volunteers and<a href=”https://www.racerocks.ca/category/ecoguardians-log/visitor-observations/”> Observers </a>on the<a href=”https://www.racerocks.ca/video-cameras/” target=”_blank”> remote control</a> <a href=”https://www.racerocks.ca/video-cameras/”>webcams. </a></strong>

<strong><a href=”https://www.racerocks.ca/video-cameras/”>This file was originally started by

Rachel de Silva PC yr32

, Dec. 2005.</a></strong></td>

</tr>

</tbody>

</table>

&nbsp;

Dendronotus subramosus : Race Rocks Taxonomy

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An 8mm long nudibranch

Thanks to Karin Fletcher on iNaturalist for identifying this for us.  She indicated that D. subramosus lack lateral papillae on their rhinophore sheaths and can have brown lines along from their rhinophores along their dorsolateral processes

https://www.inaturalist.org/observations/68751217

Domain Eukarya
Kingdom Animalia
Phylum
Order 		 Mollusca
Nudibranchia
Class Gastropoda
Clade Dendronotida?
Suborder Dendronotacea?
Family Dendronotidae?
Genus Dendronotus
Species subramosus
Common Name:Stubby-fronted Dendronotus
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 2004-  (PC) Garry Fletcher

Escape Response of California Sea Cucumber

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Parastichopus californicus escapes predation by the sunflower seastar Pycnopodia helianthoides. By releasing itself on the approach of the seastar the Parastichopus can be carried away by the current.  Also shown are the escape responses of sea urchins and topshells.

California Sea cucumber reproduction

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This California Sea Cucumber male was emitting sperm while in the tank at Race Rocks in early June, 2004 . This went on for several hours. Millions of sperm are broadcast into the water where they may have a chance encounter with eggs, also released into the current by the females. Of the great numbers of eggs and sperm released only a few are fertilized and actually make it to maturity. This is a good example of
r-selection in the population.

Gammarus sp. : Scud–The Race Rocks taxonomy

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From Wikkipedias: Gammarus is an amphipod crustacean genus in the family Gammaridae. It contains more than 200 described species, making it one of the most speciose genera of crustaceans.[2] Different species have different optimal conditions, particularly in terms of salinity, and different tolerances; Gammarus pulex, for instance, is a purely freshwater species, while Gammarus locusta is estuarine, only living where the salinity is greater than 25‰.[3] Species of Gammarus are the typical “scuds” of North America and range widely throughout the Holarctic. A considerable number are also found southwards into the Northern Hemisphere tropics, particularly in Southeast Asia.[4]
Scientific classification
Kingdom: Animalia
Phylum: Arthropoda
Subphylum: Crustacea
Class: Malacostraca
Order: Amphipoda
Suborder: Senticaudata
Family: Gammaridae
Genus: Gammarus Fabricius, 1775
Type species
Gammarus pulex Linnaeus, 1758 [1]
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.

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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Hemigrapsus nudus-Purple Shore Crab– The Race Rocks Taxonomy

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At the mid-intertidal rocky shore level on southern Vancouver Island, you will frequently find this as the most common species of shorecrab. At Race Rocks, they particularly like the loose rock habitat of the intertidal area beside the boat ramp on the jetty. The maximum size this crab attains is that shown in the video, about a 2cm. width of carapace. Thanks to Taarini Chopra and the environmental systems class for this video done as part of a study on biotic associations of the invertebrates at Race Rocks. This species is a particularly good example because of the parasites it often carries


Domain Eukarya
Kingdom Animalia
Phylum Arthropoda
Class Malacostraca
Order Decapoda
Suborder Pleocymata
Family Grapsidae
Genus Hemigrapsus
Species nudus
Common Name: Purple shore crab

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- Taarini Chopra (PC yr 27)

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)