Working with fish & salt vector sampling data

Our fish layer provides data on the following fish: tilapia, croaker, crovina, sargo, and other. We decided to use tilapia since it is the most abundant fish found. Also, tilapia is the fish that prefers waters with high salinity content.

As we look into interpolating our fish data according to year, we notice that the first year of net catching, 2003, it comes with 14 points. When we exported 2004, there were 13 points. From 2005 through 2008, it has been reduced to 11 points of data sampling. The same number of data sampling applies to the salt content data. Below is a map of the Salton Sea with symbols representing the points from 2003 and the ones lacking from the following years.

 

Missing data followed in 2005 by not adding data from the middle three points. We predict that there might be some skewed results when we run our interpolations. 

For the fish data, under the Spatial Analyst tool on ArcToolbox, we used the IDW tool for our five exported layers of fish catch data. We used the TILAPIA field for the z-value field. 

We decided to run the interpolation tool for the Salt layer as well, by exporting each layer by year. As we ran the IDW tool, we used a new field we created for the salinity content (Salinity3). We had to create a new field for our salinity layer because the integers under the original Salinity field was a string and not under integer type.