Remember that all animals need air, water, food, and shelter to survive.
For the first two survival needs, most fish use their environments in the same way:
Air- Fish breathe oxygen that is dissolved in water-just like salt can be dissolved in water. They use their gills to get the oxygen out of the water.
Water- Fish need to live in water! They don’t need any more water than what’s in their environment!
First a little background on the fish I chose to write about:
I study bluegill sunfish that are one year old.
These fish are still very small (2-3 inches) and need protection from predators. In order to be safe, they first have to survive from the time they were born until they are big enough to not fit inside their predators’ mouths.
The lakes and ponds that bluegill live in have different habitats. The open water habitat has a LOT of zooplankton that young bluegill can eat to grow fast. The areas with aquatic plants have insects and worms that bluegill can eat, but sometimes it gets crowded with other fish there. It can be harder to get lots of food in the plants.
I study how different bluegill use different strategies to deal with the predators in their environment. Let's follow Bruiser and Shyloh to see how they use their lake environment for food and shelter!
If I were a BOLD bluegill I would live…..
Some young bluegill are very risky. They have a “grow fast or bust” strategy. That means they are most concerned about getting lots of food to grow big as fast as they can.
Howdy, my name is Bruiser!
Food- I'll tell you a little about myself if you can keep up with me while I swim around looking for food. I use the open water habitat to find my food. In this open water habitat I will eat a lot of zooplankton! There won’t be as many other fish in the open water to compete with me. I will grow much faster and hopefully not fit in my predator’s mouth soon!
Shelter- ZOOOOOOM. There goes a largemouth bass! Hey you-what are you doing out there in the open! If you're going to swim with me, you have to be able to react to predators! Luckily we were both able to swim into the plants to escape him before he got us! There sure are a lot of predators out in the open water habitat! Sometimes I get so focused on eating food in the open water habitat that I barely see the predators in time to swim to shelter.
Hopefully I won’t fit inside his mouth SOON! Better get some more food! It's too dangerous for you out here- maybe you should hang out with my shy friends in the plants. Shyloh won't mind talking to you. See her? She's hiding in the plants.
If I were a SHY bluegill I would live…..
Some young bluegill are very aware of the predators in their environment. They are very cautious about looking for food and like to keep their eyes open for predators. They don’t mind growing slowly if it means they are safe.
Hi, my name is Shyloh,
Food- Hurry! Hide! If you promise to whisper I'll tell you a little about myself. Most of the time I try to eat insects and worms that I can find in this patch of plants. It's not so bad, I can find enough worms on the lake bottom or insects on the plants to survive. That is if all these other shy fish haven't already found them. The open water habitat is too unsafe for me so if I find a few worms or insects around me without looking too hard I am happy!
Shelter- Shhhhhh, don't move! I see a largemouth bass swimming into the plants to look for food (me!). If we sit still enough, he won't see us. It’s harder for my predators to see me move when I’m in the plants.
It might take awhile for me to be big enough to use the open water habitat, but I will do everything I can to make sure I survive!
