Database Reference
In-Depth Information
1: MALE6090
2: MALE90120
3: MALE120150
4: MALE150180
5: MALE180210
1:
100000 .00
2:
3:
4:
2
5:
1:
2:
75000 .00
3:
4:
1
5:
3
1
1
1
2
2
2
3
3
3
4
4
4
4
1:
5
5
5
2:
5
3:
4:
5:
50000 .00
0.00
12.50
25.00
37.50
50.00
Years
Fig. 11.11
1: F 6090
2: F 90120
3: F 120150
4: F 150180
5: F 180210
1:
100000 .00
2:
2
3:
4:
5:
1
3
1
1
1
2
2
2
3
1:
3
3
4
4
4
2:
5
5
5
4
3:
75000 .00
5
4:
5:
1:
2:
3:
4:
5:
50000 .00
0.00
12.50
25.00
37.50
50.00
Years
Fig. 11.12
To demonstrate the effect of a creel limit on the population of fish, we imposed
a 100 fish limit on the following sizes of fish - 60 - 90 mm; 150 - 180 mm; 180 -
210 mm (the smallest and two largest fishable size classes). The result is that the
entire fish population is affected (Figure 11.13).This is expected, because leaving
adult fish (capable of reproduction) in the population results in more egg production
and fertilization, and subsequently more fish in each size class. The numbers of
fish actually return to levels similar to the case when there was no fishing mortality
(70,000 - 90,000 fish).
In terms of sneaker males, an interesting result occurs. When a creel limit is
imposed, the number of sneaker males increases (Figure 11.14). This is due to the
