There's more to the HSI team!

There’s more to Habitat Suitability Indexes than what you see on our app. In fact, we have a whole part of the HSI team working on the West Coast Ocean Acidification data for another purpose.

As you know, our main species we are focusing on is Dungeness crab, and the parameters they’re affected by. Another main factor, not measured on the cruise, was aragonite saturation.

Aragonite saturation is a measure that indicates how well crabs can form healthy shells. Aragonite is an important component in crab shells. Without proper saturation, these shells won’t develop properly, and it makes the crabs more susceptible to death and stress. Our team had to calculate aragonite saturation using a formula and data provided by the National Oceanic and Atmospheric Administration.

Using presence and absence data, and the calculated aragonite saturation, the HSI team developed code that can generate a model of where within these parameters Dungeness crab can live. Aragonite saturation can be compared to other parameters within our dataset, such as pH and temperature. Take a look at the graphic below:

This HSI has aragonite saturation on the y axis and temperature on the x axis. The colored bar is an indicator of how likely you are to find Dungeness crab, and as you can see, it is pretty good at predicting where they’re going to be! There’s no presence of crabs outside of the blue areas. This code can be reused and manipulated to make many graphics like this one with different parameters, and we can see how the actual presence of crabs measures up. What a fantastic tool for seeing the actual abiotic thresholds for this amazing species! Generating data like this gives us invaluable information for the preservation of this species. How could we preserve them if we don’t know what ranges are suitable for them?