Sustaining biodiversity in fish populations is extremely important to the quality of our aquatic environment. High genetic variation in fish populations has the potential to protect them from environmental pressures like climate change, pollutants and mass mortalities due to the spread of diseases. According to research, the loss of biodiversity could also lead to the decrease in the ocean’s ability to sustain water quality and resources (Worm et al., 2006). This is why areas with high levels of biodiversity decrease are being protected (MPA’s). MPA’s are Marine Protected Areas were human activities like fishing is greatly reduced for conservation purposes.
Many professionals would come to a similar conclusion that the protection of marine areas have a positive effect on fish populations and biodiversity (Gubbay, 1995). This report studies the relationship between MPA’s, number of threatened fish species and fish species richness using quantitative data. This relationship is studied in order to find out if the protection of marine areas has any significant effect on fish populations. Two hypotheses are proposed, the first one suggests that the larger the MPA’s, the lower the number of threatened fish species seen. The second one suggests that the larger the MPA’s, the more species richness seen in the area.
Firstly, the data is uploaded into a programme called R, R is a software environment most commonly used for statistical data analysis. Once the programme is uploaded, the areas lacking MPA’s are filtered out because we are only studying marine protected environments. Normal Q-Q plots are then made for the MPA’s, number of threatened species and species richness, this is done to view the normality of the data on a graph. A Sharpio-Wilk test for normality is then used to determine if the data is modelled by a normal distribution. This test is repeated with logs of data in order to improve the normality. The Sharpio-Wilk test null hypothesis suggests that the data set is normally distributed. The normality or abnormality of the data set used here determines what tests should be taken out next. The data is plotted on scatter graphs to show the relationship between MPA’s and the number of threatened fish species and MPA’s and species richness. Linear models are used to show trend lines on the graphs. The results generated allows the visual study of the effects of MPA’s on fish populations globally, therefore, allowing the acceptance or rejection of the hypothesis proposed.
Figure 1 shows the normal Q-Q plot for the Marine Protected Areas. The results of the Sharpio-Wilk test suggests that the data does not follow a normal distribution (p = 2.2e-16) this allows us to reject the null hypothesis the sharpio test suggests. Figure 2 and 3 also shows similar trends with p-values <0.05 (p = 5.387e-12 <0.05, 1.83e-13 <0.05), meaning they do not follow a normal distribution, allowing the rejection of the null hypothesis. Figure 4 shows that the normal Q-Q plot for the Marine Protected Areas data remained abnormal even after being logged (p = 0.002906). On the other hand, the dataset for both the number of threatened fish species and the species richness became normal after being logged (p = 0.6289, p = 0.37). This can be seen in figure 5 and 6. Figure 7 shows the relationship between Marine Protected Areas and number of threatened fish species on a scatter graph. The trend line shows a significant positive correlation (F-statistics (1,120): 9.91, p-value = 0.002074). Studying figure 8, similar trends can be seen. The relationship between Marine Protected Areas and fish species richness also has a significant positive correlation F-statistics (1,120): 23.62, p-value: 3.582e-06). These results suggests that MPA's have a positive effect on the fish species richness.DiscussionStudying the results, It can been seen that the first hypothesis cannot be accepted. This is because the hypothesis suggests that the higher the MPA's the lower the number of threatened fish species in the area but our results suggest the opposite. There is a positive correlation shown between these two variables (figure 7) meaning that there is a high number of threatened fish species in Marine Protected Areas. Although it is assumed that Marine Protected Areas reduce the number of threatened species, the rejection of the first hypothesis is not surprising because usually an aquatic environment is protected due to the high numbers of threatened fish species in the area. Human activities in these areas are greatly reduced in order to protect these threatened species. Although there is no evidence of MPA's having a positive effect on number of threatened fish species in the results, there are several cases of MPA's being effective for conservation purposes. Research by Gill et al (2017) states that MPA's are being used more globally due to their ability to reduce environmental pressures for threatened fish species. Over 70% of MPA's have a positive effect on threatened fish populations. The results also show a positive correlation between the MPA's and fish species richness in the area (figure 8), this means that the second hypothesis can be accepted. The positive correlations shows that there is a high level of species richness in areas with a higher amount of MPA's. Due to regulations in MPA's, fishing is disallowed. This alone can have a huge positive effect on fish species richness and lead to an increase of fish biodiversity in the protected area. In conclusion, Marine Protected Areas evidently have a positive effect on fish populations by attempting to reverse human effects on the aquatic environment. However, some MPA's fail to reach threshold for effectiveness and it is argued that this is due to many factors such as regulations that allow legal fishing occasionally and the emigration of fishes outside protected boundaries due to lack of space (Gill et al., 2017; Edgar et al., 2014 ). Some researchers argue that MPA's do not reduce fishing effort, they just move it somewhere else and this effort displacement is recognised as a result of Marine Protected Areas (Halpern et al., 2004). From the results presented in this report and many external research, MPA's can potentially have a positive effect on fish populations but only when these organisations are not compromised for immediate human benefits.