Fish Jump by Debbie Kay
There are a number of videos and stories about the way that salmon and trout can muscle their way upstream and leap up waterfalls. But how high do fish jump? For many species, we don’t yet know the answer. For others, there is some good science available. Here is a look of some of the best known salmonids and the information we have on their ability to leap waterfalls in a single bound:
Why the Fish Jump Studies?
Fish passage has long been an important part of keeping fish populations healthy, especially when it comes to species who spawn in streams and are sea-run or large lake-run for part of their lifetime. Hanging culverts, dams and other manmade blockages can destroy populations unless there are measures put in to allow these fish the chance to still access the length of their home stream. As requirements for fish passage are being made, species specific information on the ability to swim in different gradients of water and leap barriers of different heights can help to keep fish populations healthy in developing areas.
What do Fish Need to Jump?
Fish don’t typically jump an entire waterfall in one leap. If the cascade is stepped or pooled, they have a much better chance of getting up the slope. When looking for fish habitat above a natural waterfall, this is one thing to consider. Another is the jumping rule of thumb, which states that fish jump up to twice as high as a pool is deep. Shallow pools, in other words, limit the room that a fish needs to make one of their larger leaps.
Brook trout are one of the best studied species regarding the height that they can jump because these introduced fish are being excluded from areas containing native cutthroat trout in many areas. They have been shown to jump at least 4 times their body length in height.
Juvenile coho are believed to be able to jump approximately 5 times their body length. Adults can sometimes pass barriers 12 feet in height, particularly if there are resting pools available along the gradient passage.
These fish are known to also make a vertical leap of approximately 12 feet at a waterfall in Scotland. Though some places claim that they can jump a 20 foot waterfall, the falls where this occurs typically have some kind of resting pool along the way.
Shortfin Mako Shark
While most of the studies these days on leaping height and fish passage are being done on salmon and trout, there is something to be said for the ability of open water fish to jump as well. Open water fish are muscular swimmers, and there have been marlin and some rays jumping almost 10 feet into the air. The world record holder for aerial jumps belongs to the shortfin mako, also called the blue pointer or bonito shark. This fish can be found worldwide in tropical regions, and has been known to leap 6 meters or over 19 feet into the air.