Using mark-recapture to determine the mortality rate of sauger in River Ohio

Using mark-recapture to determine the mortality rate of sauger in River Ohio

Title: Using mark-recapture to determine the mortality rate of sauger in River Ohio.


Fishing mortality rates have been on the increases thus the need to design the management plant to estimate the population of the threatened fish species and protect the remaining species. One method of estimating fish population in the sea, river, or pond is a mark-recapture method.  The study by Seibert et al., (2018) indicates that there has been a decline in sauger population in River Ohio. However, much information on the measurements on the factors that leads to the declining rate of sauger in River Ohio. High mortality rates could result from the destruction of habitat due to continuous modification of the environment around River Ohio. It could also be as a result of overfishing.

It is, therefore, necessary to measure the rate at which these factors contribute to the decline of sauger’s population and develops effective strategies to rebuild the stock of sauger population. This study is thus essential as it will avail significant information on the factors that contribute to the reduced population of sauger and help in strategizing on which methods will be useful in restocking the sauger’s population in River Ohio. This study aims to determine the effectiveness of the mark-recapture method in establishing sauger’s mortality rate in River Ohio and factors that contribute to the mortality rates. The hypothesis is that mark-recapture is an effective method to determine the mortality rate of sauger as it does not harm the species thus easy to identify the population and minimizes the possibility of error.


  • The study will take place in River Ohio for three months and will focus on the varying population of sauger fish.
  • The method of data collection will be the fish sampling of the open sections of the river Sampling will occur after the sunset. The study will use a sample size of 50 fish.
  • There will be the recording of the estimated age of the fish and the use of the mark and recapture method to identify the fish that have been studied thus avoid confusion.
  • The mark-recapture method will provide useful information on the population size of sauger within three months. Using a sample of 50 sauger fish, they will all have a harmless mark on their tail, and then record the number 50 as the first capture.
  • They will then be let free to mix in the river with other fish species, and after one month, there will be capturing of sauger fish with the mark on their tail.
  • The expected outcome is that there will be a reduced number of captured sauger fish with mark for the second time.
  • The population will have been recorded, and they are left to move freely in the river. Another data collection will happen after another month, and it will also involve capturing marked sauger fish and recording the number.
  • The data on the factors that contributes to the declining population size will be available from the local industries on their observation on the fishing rates since the development of the areas along River Ohio.
  • Fishers living along River Ohio will also give their experience on fishing on an interview. The statistical test that will aid in the analysis of collected data for this study is linear regression and correlation. It will show the relationship between the declining sauger population and the factors that contribute to the declining population.
  • The expected results will show a decline in sauger population. Excel will also be an appropriate tool to estimate the sauger fish population. The study will have a correlation range from -1 and +1 depending on the strength and direction of linear associations between the variables.










Seibert, K. L., Whitledge, G. W., Rude, N. P., Oliver, D. C., Loubere, A., & Seibert, J. R. (2018). Population Demographics of Sauger and Simulated Effects of Minimum Length Limits in the Kaskaskia and Ohio Rivers. Journal of Fish and Wildlife Management9(2), 431-445.