For example, you may remember Dr. Marcus Drymon's discovery of land birds in tiger shark stomachs. It's a discovery that was highlighted on Nat Geo Wild's Blitzkrieg Sharks earlier this year.
Sharks aren't the only marine animals with some interesting eating and digesting habits. Miaya Glabach, a research technician in Dr. Will Patterson's lab, spends her days looking at the contents of a variety of fish stomachs. Glabach answered a few questions to help us understand why scientists are interested in what fish eat.
What's the importance of knowing the contents of a fish's stomach?
By identifying what a fish is eating, we can learn many different things about a fish; where they are eating in the water column, how their eating habits change seasonally, how they change regionally as well as what types of communities on certain sites based on what has been found in stomachs.
What's the most interesting stomach you've worked with?
One stomach I have had the most fun with has been lionfish stomachs. I have only started processing them within the last few months. Lionfish are such voracious eaters, and eat anything they can fit into their mouth, you find a large assortment of different prey items. We have found that the smaller lionfish seem to eat more shrimp and small crustaceans; whereas the larger lionfish will still eat crustaceans, but eat far more fish.
How do you identify the contents of a stomach?
When I first started on stomachs, a lot of it was asking others. Now that I have been doing it for a while, I have learned different resources that I can use to aid in the identification of different items. We have some invertebrate guides that we use as well as several different fish guides with keys to help us identify based on characteristics what species of fish we have since most times the skin is the first item to digest, we cannot use that as an indicator of species.
What's the most shocking thing you've found in a stomach?
The most shocking thing I have ever found in a stomach was a telemetry tag from a fish that we had tagged the previous day. The fish was pulled up as our team tagged red snapper. The back end had been bitten off by a shark. Instead of tagging the fish and releasing it with almost full certainty that it would die quickly, we sampled the fish with our usual protocol (tissue, stomach, otoliths). When I went to go and process the stomach, I opened it up and found a partial skeleton of another fish, as well as one of the telemetry tags from a fish that we had tagged the day before. We were able to see the ID number on the telemetry tag and see what size fish it had been on.
How did you get into looking at fish stomachs?
When I first joined the lab, there was a huge backlog of stomachs that had not been processed, and this is where my involvement of stomach analysis started. It was a long process of working with students in the lab and learning how to identify, as well as learning all the different items that could be in a stomach. Even a year later, I am still finding new prey items and have to do research to identify what they are.