Part A
Draw a CLD to explain the fish regeneration dynamics of ‘Lakeland Reserve’ based on the initial 500 fish in the Reserve area, assuming there is no fishing or other source of predation. Sketch a BOT graph as a reference mode that shows the pattern of change of the fish population over the 40 year period. Briefly explain the dynamics that your CLD reveals, any archetypal patterns of behaviour, and any other insights your initial analysis demonstrates. (This task has similar requirements to Assignment 1).

BOT
The BOT demonstrates the patterns of behaviour the fish population at ‘Lakeland Reserve’ over 40 years
Year
FISH POPULATION
PATTERN OF BEHAVIOUR OF FISH POPULATION

500
1000

1500
2000
2500
3000
3500
4000

40

Figure 1
As shown in Figure 1, at the beginning (t=0) there are only 500 fishes. Hence, more fishes are added to the reserve and the fish population in the reserve keeps growing. The rate at which fishes are added is at an accelerating rate. However, when the reserve reaches its maximum capacity at 4000 fishes, the fish population starts to decline at a diminishing rate.

CLD
The CLD visualizes the interrelated variables in terms of the behaviour of fish population at ‘Lakeland Reserve’ during this period

Figure 2

Figure 2, the casual loop diagram including three loops (two reinforcing loops and one balancing loop), demonstrates the fish regeneration dynamics of ‘Lakeland Reserve’ based on the initial 500 fishes in the Reserve area, assuming there is no fishing or other source of predation.
As shown by R1, as the amount of food increases, the number of fishes in the reserve increases accordingly. As the result, a rise of fish density occurs and it gives rise to the growth of the regeneration rate, consequently in turn having a positive effect on number of fish. And it is similar to R2.

However, according to B2, with the fish density arriving 60%, the amount of food allocated to each fish is decreasing. Consequently, the rate at which fishes are added will diminish until the reserve approaching its maximum capacity which is 4000 fishes.

Archetypes

LIMIT TO SUCCESS

Figure 3

As demonstrated in Figure 3, the effort is the creation of the Lakeland marine reserve. As fishes is added to the reserve, the number of fishes in the reserve increases. Therefore, the fish density in the lake amplifies and it is the slowing action. Additionally, as the lake reaches its limit, the constraint is the decreasing amount of food given to the fishes. Consequently, the number of fishes in the lake will diminish as the fish population in the lake is greater than the amount of food given.