Throughout my 26 years on this earth, I’ve lived in a lot of different places. I’ve moved from a nice suburban home outside Washington D.C. to a cramped dorm room in Charlottesville Virginia. I’ve lived in both the smallest and largest states (by area) in the continental U.S., both of which suited different needs of mine at different points in my life. When you’re young, you live at home out of necessity; when you’re a little older, you move away to explore new places and encounter new experiences. Some folks decide to settle down when they’re a little older in a place suitable for children, others close to their own families. As we grow, our needs change. And as our needs change, we move to better accommodate those needs.
I’ve just illustrated the ecological notion of ontogenetic habitat shifts. This is just a fancy way of saying that animals use different types of habitats throughout their life. We’ve talked before about how juvenile animals are often found in nursery habitats, like wetlands or seagrass meadows that provide plenty of food and shelter from predators. However, many of these organisms also move to deeper waters as they get older and outgrow their nursery habitats. From a management standpoint, it’s absolutely essential that we understand these movements so that we can better protect certain species of concern.
A team of researchers out of Japan and the Philippines, led by Dr. Kentaro Honda of the Hokkaido National Research Institute, examined habitat use of 265 species of fish off the coast of the Philippines to better understand which coastal habitats these species frequently utilize. Over the course of the two-year study, Dr. Honda and colleagues found that over 77% of the individual fish were frequently observed in coral reed habitat compared to seagrass and mangrove habitat. Approximately 14.4% of the recorded species shifted between multiple habitats throughout their life, suggesting that we cannot necessarily protect coral reefs over seagrasses and/or mangroves. When considering just commercial fish, the percentage of species that utilize multiple habitats jumps to 20%.
These findings aren’t necessarily groundbreaking; scientists have known for quite some time that animals migrate between habitats throughout their life. However, many conservation policies are focused around protecting a single habitat. “Protect the coral reefs” and “Save the wetlands” are great slogans, provided they don’t become mutually exclusive. In order to adequately protect marine animals, we need to save the wetlands, coral reefs, seagrass meadows, mangroves, and everything in between. That’s not to say we can’t concentrate our efforts on what habitat at a time, we just can’t lose sight of the overall goal: protection for all habitats.
Enjoy the Podcast!