Growth of Dace and Roach in the River Exe Catchment
Fish Age and Growth Case Study: Growth of Dace and Roach in the River Exe Catchment
Age 1
Age 5
Age 4
Age 3
Age 2
Age 0
Figure 1 Length frequency histogram of Fortesque Dace.
This figure clear shows that there is a distinctive overlap between the different age groups of the dace from the Fortesque sampling site on the Rive Exe
Figure 2. Observed mean length and 95% confidence limits for dace (Esk).
This figure clearly shows that there is a large difference in length for individuals aged between 2 and 5 years. This indicates that those aged between 2 and 5 grow at a more rapid rate than that of those aged 0 and 1 year.
Figure 3. Log length/Log weight relationship with regression equation. (Fortesque dace,).
Y= 3.1439x – 5.1193 R2 = 0.9948
P = 1.02665E-90
From this graph it is can seen that there is a clear correlation between the length and weight of dace
Data analysis regression
Table 1. Back calculation of growth: Mean length for age of each group
Age Mean Length
1 74.8
2 123.4
3 167.5
4 211.8
5 239.4
Figure 4. The back calculation growth means length of age Fortesque dace. There is a strong positive correlation between the body size and the fish scales used for ageing the fish
Figure 5. Ford-Walford plot to determine Linf and K
This graph shows the maximum length of infinity of old fish of the Fortesque dace.
Figure 6. Validation graph to test Linf of Fortesque Dace
Table 2. t0 estimation based on each age, and the mean t0 value Fortesque Dace age,
Age | to | 1 | 0.064171 | 2 | 0.068401 | 3 | 0.122595 | 4 | 0.065133 | 5 | 0.016738 | mean | 0.044954 | |
Figure 7. Validation graph to test Linf.
Figure 8. Von Bertalanffy growth curve of Fortesque dace
.
Figure 9. Length-by-age (mm) of Roach at Exe R. Creedy, Exe Trew’s weir and Culm Stoke Canon. (Data compiled from Ian Cowx’s table of length-by-age)
Figure 10. Length-by-age (mm) of Dace at
Age 1
Age 5
Age 4
Age 3
Age 2
Age 0
Figure 1 Length frequency histogram of Fortesque Dace.
This figure clear shows that there is a distinctive overlap between the different age groups of the dace from the Fortesque sampling site on the Rive Exe
Figure 2. Observed mean length and 95% confidence limits for dace (Esk).
This figure clearly shows that there is a large difference in length for individuals aged between 2 and 5 years. This indicates that those aged between 2 and 5 grow at a more rapid rate than that of those aged 0 and 1 year.
Figure 3. Log length/Log weight relationship with regression equation. (Fortesque dace,).
Y= 3.1439x – 5.1193 R2 = 0.9948
P = 1.02665E-90
From this graph it is can seen that there is a clear correlation between the length and weight of dace
Data analysis regression
Table 1. Back calculation of growth: Mean length for age of each group
Age Mean Length
1 74.8
2 123.4
3 167.5
4 211.8
5 239.4
Figure 4. The back calculation growth means length of age Fortesque dace. There is a strong positive correlation between the body size and the fish scales used for ageing the fish
Figure 5. Ford-Walford plot to determine Linf and K
This graph shows the maximum length of infinity of old fish of the Fortesque dace.
Figure 6. Validation graph to test Linf of Fortesque Dace
Table 2. t0 estimation based on each age, and the mean t0 value Fortesque Dace age,
Age | to | 1 | 0.064171 | 2 | 0.068401 | 3 | 0.122595 | 4 | 0.065133 | 5 | 0.016738 | mean | 0.044954 | |
Figure 7. Validation graph to test Linf.
Figure 8. Von Bertalanffy growth curve of Fortesque dace
.
Figure 9. Length-by-age (mm) of Roach at Exe R. Creedy, Exe Trew’s weir and Culm Stoke Canon. (Data compiled from Ian Cowx’s table of length-by-age)
Figure 10. Length-by-age (mm) of Dace at
References: Brabrand, A. 1985. Food of Roach (Rutilus rutilus) and Ide (Leusiscus idus): Significance of Diet Shift for Interspecific Competition in Omnivorous Fishes. Oecologia. Vol. 66(4). pp 461-467. Cowx, I. G. 1988. Distribution and variation in the growth of roach, Rutilus rutilus (L.), and dace, Leuciscus leuciscus (L.), in a river catchment in south-west England. Journal of Fish Biology. Vol. 33(1). pp 59-72. Cowx, I. G. 1989. Interaction between the roach, Rutilus rutilus, and dace, Leuciscus leuciscus, populations in a river catchment in south-west England. Journal of Fish Biology. Vol. 35. pp 279-284. Nunn, A. D., Harvey, J. P., Cowx, I. G. 2007. Variations in the spawning periodicity of eight fish species in three English lowland rivers over a 6 year period, inferred from 0+ year fish length distributions. Journal of Fish Biology. Vol. 70. pp 1254-1267. Weatherley, N. S. 1987. The diet and growth of 0-group dace, Leuciscus leuciscus (L.), and roach,Rutilus rutilus (L.), in a lowland river. Journal of Fish Biology. Vol. 30(3). pp 237-247.