Using maps and investigating catch rates to understand lobster abundance in Nova Scotia waters

Once students better understand the species, they can explore the interaction between lobsters and fishers. One excellent way to do this is to use maps to explore the spatial distribution of lobster in different water areas surrounding Nova Scotia. Maps also offer an opportunity to draw attention to where the Mi’kmaq live in relation to non-Indigenous people in Nova Scotia. Fishing has been – and continues to be - vital to the lives of Indigenous Mi’kmaq people since well before the area was colonized by Europeans. A recent article in the Toronto Star (2019) interviewed Alanna Syliboy of the Mi’kmaw Conservation Group who said that a two-eyed seeing approach (using both Indigenous and Western knowledge) will only benefit fisheries. However, it is important to keep in mind that Indigenous voices need to be included from the beginning, not as an afterthought as so often has happened in the past.

There are many ways to measure the abundance of lobsters. One way an abundance of lobsters has been measured in Nova Scotia is by using Catch-per-unit-effort (CPUE) or catch rate. This is a quantitative index describing how many lobsters of a certain size are caught per trap. In the following lesson, students explore the spatial patterns of lobster abundance in different water areas surrounding Nova Scotia.

Curriculum Goals

Grade 6: Science

Understanding Life Systems

Investigate the characteristics of living things, and classify diverse organisms according to specific
characteristics
Demonstrate an understanding of biodiversity, its contributions to the stability of natural systems,
and its benefits to humans

Understanding Earth and Space Systems

Investigate characteristics of the systems of which the earth is a part and the relationship between
the earth, the sun, and the moon

Grade 6: Math

Number Sense and Numeration

Demonstrate an understanding of numbers and make connections to the way numbers are used in
everyday life
Use knowledge of numbers and operations to solve mathematical problems encountered in
everyday life

Patterning and Algebra

Identify, describe, extend, create, and make predictions about a variety of patterns, including those
found in real-life contexts

Data Management and Probability

Describe the likelihood that events will happen, and use that information to make predictions

Geometry and Spatial Sense

Describe and represent shape, location, and movement by applying geometric properties and
spatial relationships in order to navigate the world around them

Measurement

Estimate, measure, and record length, perimeter, area, mass, capacity, volume, and elapsed time,
using a variety of strategies

Lesson

Show a map of the lobster fisheries that border Nova Scotia (Appendix A).
- Identify and mark where the First Nations are located (Appendix B). This helps to bring awareness of the number of Mi’kmaw communities in Nova Scotia.
Teach children about the ways marine biologists have used CPUE to measure the abundance of lobster in an area by showing students a map of the annual spatial patterns of lobster abundance over 7 years (Appendix C). Points include:
- Map shows the size of lobsters (61-70 Carapace Length (CL), just under the minimum weight before being legally caught) and the number of lobsters in that area. More information about lobster traps.
- Lobsters must be a minimum of 82.5 mm Carapace Length before being caught.
- One trap fits a maximum of 10-12 lobsters during a good fishing season.
- Catch-per-unit-effort is the number of lobsters caught per trap.
Discuss which areas are most abundant in lobsters and why students think these areas are well populated. Theories might include ideal temperature and access to food. More info on lobsters.
Then show the second set of maps (Appendix D) which describes the abundance pattern of lobster eggs, ovigerous (egg bearing) lobsters, or 61-70 CL lobsters.
In groups, assign students a fishing region (e.g. Fishing Area 34) and have students add up the number of eggs, ovigerous, and 61-70 CL lobsters in that area.
- Students record their findings in a table (Appendix E).
- Fishers are not allowed to fish ovigerous lobsters.
Come together as a class and discuss theories about why lobster eggs, ovigerous lobsters, and mature lobsters appear to be abundant in different water areas.

Look Fors

What questions do children ask about the location and movement of lobsters?
How easily are children able to read the maps and determine which fishing area has the greatest number of lobsters?
Can children extrapolate from the maps to determine where fishing should take place?
Can children add using decimals?

Extension

Study the water areas surrounding Nova Scotia and how this affects the lobster. Ideas include water temperature, water currents, and access to food.
Explore the number of lobster traps set by Mi’kmaq fishers and commercial fishers. See fishery scale comparison between Sipekne’katik fishery and commercial fishery.
- Ask what factors we need to consider before determining whether this is a fair distribution of traps? (e.g. number of fishers per trap)
More maps showing total number of traps by fishing area, catch weight, catch weight per trap haul etc.