Posted on: June 29, 2012
Have you been down the beach recently? The weather is probably not enticing you … nor the smell, but it’s a great time to find some really cool things washed up on our beaches. A class of Year 8’s on excursion to the Naturaliste Marine Discovery Centre recently, had a great find whilst on their Beach Exploration. Lying in amongst the reasonably large sea wrack on Hillarys beach were not one, but three juvenile Port Jackson sharks, presumably just hatched, as egg cases were found nearby!
You can learn more about the things we find washed up on our beaches from the Perth Beachcombers Education Kit. Download the Beachcombers Field Guide to see what organisms look like both under the water, and when they are washed up on the beach.
What exactly is a sea wrack? A sea wrack is made up mainly of seagrasses and seaweeds, but the composition depends on where you are on the coast. The washed-up material reflects the ‘plant’ species abundant offshore – e.g. in Geographe Bay, sea wracks are composed largely of seagrass. To learn more about what you find in the sea wrack, check out our poster – Dynamic link between ocean and land.
Sea wracks have also been studied over the years by fisheries scientists and they now know there is a correlation between the composition of the wrack and the juvenile fish species that use it for food and shelter. Turns out, some juvenile fish (just like many juvenile humans) are fussy eaters! Read our article C’mon and Embrace the Smell to learn about the juvenile fish species that use the sea wrack, and also learn about the human uses of seaweed. Ask your students to research other products that have seaweed in them … they may be surprised how much seaweed they consume without even realising it!
If you’re really game, why not take your class on a trip to the beach … raincoats are recommended and remember, never turn your back on the ocean.