Similarities and differences: wild and farmed green-lipped mussels In this activity, students use a paper-based Venn diagram to illustrate the key similarities and differences between how wild and farmed green-lipped mussels live.
By the end of this activity, students should be able to:
describe the key similarities and differences between farmed and wild green-lipped mussels
understand how to use a Venn diagram to graphically organise information.
What you need
What to do
List of features
Venn diagram worksheet Introduction Wild green-lipped mussels grow abundantly in New Zealand’s coastal waters, and green-lipped mussels are also cultivated (farmed) here. At present, most farmed mussels begin their lives in the wild – they are grown from spat that has washed ashore on seaweed on Ninety Mile Beach and elsewhere. This means that wild and farmed mussels are not distinct populations. This differs from the traditional concept of ‘farming’, in which farmed animals or plants are isolated from their wild counterparts and bred in captivity over successive generations. (Note, though, that some green-lipped mussel larvae are raised in hatcheries, and mussel breeding programmes are under way.)
Although they arise from the same wild populations, there are some key differences between how wild and farmed mussels live during the adult phase of their life cycle. Exploring those similarities and differences can provide students with a framework for developing their knowledge of mussel biology and aquaculture.
The following table provides a summary of similarities and differences. Refer to the information sheets Life of a green-lipped mussel and New Zealand’s green-lipped mussel industry to find the information that is required to complete the activity.
Venn diagrams have been used for over a hundred years as a visual way to show the similarities and differences between two or more things (for example, concepts or products).
In a Venn diagram, two or more circles overlap – features present in only one thing appear in its circle, and features common to both appear in the overlapping area of the circles.
For example, farmed mussels (but not wild mussels) are grown on ropes suspended in the ocean, so this feature belongs in the ‘Farmed mussels only’ area, but both wild and farmed mussels feed on phytoplankton, so this feature belongs in the overlapping area (both wild and farmed mussels).
What you need
Access to the printed list of features and Venn diagram worksheet
Access to the information sheets Life of a green-lipped mussel and New Zealand’s green-lipped mussel industry
Access to the Mussel life cycle diagram
What to do
Have the students read the information sheets Life of a green-lipped mussel and New Zealand’s green-lipped mussel industry
Draw a sample Venn diagram on the board and discuss with the students what it can be used to show. It might be helpful to model how it works with another example, such as a lake and the sea.
Allow the students sufficient time to complete the Venn diagram, either individually or in small groups. Provide the list of features either as a handout or put up on the board and ask students to complete the Venn diagram worksheet in pencil.
Give individuals or groups the opportunity to feed back. Any disagreements can be resolved by referring to resources within the focus story Farming green-lipped mussels.
Are all mussels in New Zealand farmed using the same methods? Which stage in the farming process varies the most?
What constitutes ‘farming’? How does mussel farming differ from other species that are farmed on land in New Zealand (such as sheep or cattle)?
Annotate the Mussel life cycle diagram on an interactive whiteboard to demonstrate at which stages the lives of farmed and wild mussels differ (and how).
Write a first-person account of the life of a farmed and a wild mussel.
Research farming methods for other New Zealand aquaculture species and compare them with the methods used to farm mussels, for example, Pacific oysters are farmed in a similar manner to green-lipped mussels, whereas salmon are farmed using different methods. These Aquaculture in Action fact sheets provide a good starting point for independent research.
View the video series Mating mussels to learn about the mussel breeding programme at the Cawthron Institute in Nelson.