https://www.oceannetworks.ca/tides is a good reference on the cause of Tides

At Race Rocks we have a tidal range of about 3 metres.

For tidal Level predictions , from the closest station at Pedder Bay see this link

http://www.tides.gc.ca/eng/find/zone/9

 

 

 

 

 

The link below is for the Race Passage Current tables.  .. See this file for the result of original work done by Pearson College Divers assisting Institute of Ocean Sciences in the deployment of the current meter to gather a years worth of data from which these tables are constructed. 

 

 

 

 

 
Marine Science teacher at Pearson College Laura Verhegge was interviewed on CBC radio about what was a “Negative tide”. Listen below.

 

The role of the moon is a major factor in determining the rise and fall of the tides.The view of it from Race Rocks in a full sky is often stunning. 

And of course the other component causing tides is the sun. See this file for Solar energy records for Race Rocks .  

 

 

See this file for the Abiotic Effect of Solar energy on Organisms at Race Rocks

 

 

THE ABIOTIC EFFECTS OF TIDAL LEVEL CHANGES:

The rich variety of life in the intertidal zones of Race Rocks provide habitat for many animals which have adapted to living part of their life exposed . “ANITA’S ISLAND” on the West side of Great Race Rocks provides an excellent example,  in the month of June when the tidal level often drops below zero datum so one can really appreciate the effects of the daily changing tidal levels on intertidal life. This island is actually a peninsula which you can walk out onto when the tides drop to -0.0m, but is totally submerged at high tide, (around 2.6 meters). You can often see the top of it from remote camera1  ( It looks black because it is covered with mussels.)

For several years in the 1990s  we did research with Dr. Anita Brinckmann-Voss on these low tides in June. We only had a half hour or so until the isthmus joining the island to Great Race Island was flooded however. Each year that we went out, Anita found a great many of the hydroid samples from which she identified for the Ecological Reserve.  

THE INTERTIDAL ZONE: The island is totally covered on every square centimeter with some form of life, either invertebrate or plant. Those organisms nearer the top or in the high intertidal area, are more resistant to changing temperatures, and changing salinity. Exposure in a rain storm means they have to tolerate fresh water, and changing salinity.  On a hot sunny day , the surface temperatures can elevate quickly.  Other hazards of this habitat between sea and land create an extreme environment for survival. Predation from Birds and other animals is possible when exposed at low tide , wheres the same organisms are exposed to predation from fish and predatory invertebrates such as sea stars when the tide is in.  This zone also makes the organism vulnerable to pounding waves and surf, so built in resilience is necessary to hold on and remain attached , and not be crushed by the force of the water. Living in this zone also leaves an organism exposed to wind driven foreign objects.. At Race Rocks drifting logs are often present on the surface and these can exert a powerful force when striking a shoreline,  RESEARCH ESSAYS: The implications for an organism living at different elevations on the intertidal zone are very significant. Over the years several students have done research in the intertidal zone at Race Rocks and have examined how different organisms have adapted. Check this file for examples  TIDEPOOLS: In our tidepool file , you will find an index with links to a set of tidepools where we have recorded the effects of the tide being out for different lengths of time. The abiotic conditions in the pools change significantly as the tide levels go up and down. Salinity and Temperature are especially variable and they influence the type of organisms that lives within the pools. Intertidal TRANSECT Studies.We use transects to quantify the interrelations of organisms as they are distributed throughout the intertidal zone on the shore. Tidal levels are a major factor in determining this zonation. In this file you are invited to examine some of our data, and create your own transect baseline studies as well. They may have nothing to do with tides, but they can serve as an excellent record which you may use to base measurements showing change or stability of the ecosystem in the future The Effects of CURRENTS.  Tidal Currents are also a result of the tidal cycle . This file documents aspects of the Currentsa at Race Rocks   Other tidal heights from along the coast of Vancouver Island and British Columbia An interesting exercise is to compare the tidal heights at several locations around Vancouver Island. There is a significant difference, with times as well as tidal ranges varying depending where the station is located. There are many factors which determine tide levels, the most obvious being the stages of the moon and the position of the sun, but here you can see that geography has a major role to play as well.