I am studying relations between migration movements of different types of fish and acidity (pH) of water. I am stuck on which statistical test i should use to find those significant correlations and/or regression.
The data are structured:
Date column (between the start of 2021 and the start of 2022)
pH (mean pH for every date)
Fish data column (how many fish of one species traveled through, what we call a fishlift). This fishlift lets fish travel from one watercourse to another.
I am trying to test if the migration of fish (fish using the fishlift) is caused by changing pH. I've tested if the fish data is normally distributed (it is), but I've come to realize that my data is not linear, but more or less parabolic. Also my data contains a lot of zeros (since the fish didn't use the fishlift every day).
Can someone explain which type of statistical analysis I should use?
I almost used ANOVA, but I realized that the data is heavily dependent on itself (since a fish could have entered and then left the watercourse on the same day, which would count as 2 observations). Also I added two time plots, to show the year observations.