Electroreceptors of Paddlefish

Electroreceptors of Paddlefish

The American paddlefish is an interesting but relatively unknown fish species. These fish have large paddle-shaped appendages on their foreheads, and they inhabit the murky waters of the Mississippi River and its tributaries. They can grow to six feet (183 cm) and weigh 150 pounds (68 kg). So what is the purpose of the paddle? The electroreceptors of paddlefish answer that question.

You might think that the paddle is a device to dislodge food from river bottoms. Some people called them “shovelnose fish,” assuming they used their paddles as a shovel. But paddlefish don’t dig for food, and lab experiments in 1993 showed the paddle’s real purpose.

Paddlefish are filter feeders that feed on tiny crustaceans and insect larvae that drift through the water as plankton. Many whale species are filter feeders that use comb-like baleen in their mouths to strain their food from the water. Paddlefish have comb-like rakers in their gills. They swim with their mouths open and filter their food from the water. But that doesn’t explain the paddle.

Paddlefish have poor eyesight and no sense of smell, so how do they know where to swim to find food? The paddle is covered with tens of thousands of electroreceptors that can sense extremely minute electric fields. Plankton emit signals that are similar to what doctors measure in electrocardiograms. Paddlefish use their electroreceptors to detect those signals and locate the plankton, even in murky waters.

The electroreceptors of paddlefish are similar to those of the platypus found in Australia. Many marine fish, including sharks, skates, rays, and some freshwater fish, can use weak electrical signals for feeding and communication. Those fish don’t need light or clear water to eat and maintain a balance in the environment. This ability is not something that evolved in the paddlefish because fossil evidence seems to indicate that they had electrosense ability very early in Earth’s history. We are amazed by God’s designs that we see in living things.

— John N. Clayton © 2020

Ice Algae – Designed Polar Grass

Ice Algae
Have you ever wondered how animals that live near Earth’s North and South Poles survive? What do they eat, and how can any kind of food chain exist? The answer to this is ice algae.

Unlike most plants, algae do not have flowers, roots, stems, leaves, or vascular tissue. However, ice algae, like most plants, provide the starting point for a food chain. In this case, it is a food chain in very cold places. Tiny krill, penguins, seals, polar bears, and blue whales all depend on ice algae to survive. In 2016 Dr. Thomas Brown of the Scottish Association for Marine Science studied polar bears and found that 86% of the polar bears’ nutrition came from a food chain that originated with ice algae.

Ice algae have chlorophyll so they can use whatever light is available for photosynthesis. There are a variety of types of algae that live in different conditions. Some live on the surface of the ocean, some on the floor of the ocean, and some in or on the ice itself. Ice algae produce fatty acids which supply nutritional value for animals that live in what would otherwise be a nutritional void. Because there is ice algae, animal life is abundant under, in, and around the ice at both poles.

God has provided interesting food chains all over the planet. As we study global warming and its effect on life in places like the polar seas, we see more of His handiwork and learn why we need to take care of it. The admonition of Genesis 2:15 to “take care of the garden to dress it and keep it” applies as much to us today as it did to Adam and Eve.
–John N. Clayton © 2019

Data from National Wildlife, February/March 2019, pages 14-16.