Anchovies can smell plastic pieces in the ocean and mistake them for food.
Plastic bits or food-they all smell the same to me. Hi, I’m Annie, and I’m an anchovy. You may have seen my colleagues in a tin can (may they RIP), or in the ocean in a large shimmery school that’s hopefully not being eaten by large predators such as sharks and dolphins, eek!
You might also wonder how we can smell in the first place, as we live underwater. Chemicals travel through the water and into my nostrils, just like they do in the air for terrestrial animals. Sharks can smell blood from very far away or in low quantities. Salmon use their sense of smell to navigate back to their birthplace spawning ground upstream.
Back to the plastic bits-humans have found that over 50 kinds of fish mistakenly eat plastic, thinking that it’s food. That includes my friends and I. A neat study by humans using an anchovy school in an aquarium (Aquarium of the Bay in San Francisco, California) found that by measuring our schooling behavior (how tight we schooled and our body position relative to water flow) that we:
1. Use odors to locate food
2. Plastic pieces are confusing to us due to their similarity to food in appearance and smell
So what can you do to help? Avoid single use plastics (SUP) whenever possible and recycle if you do buy them! Less than 7 percent of plastic in the U.S. gets recycled. Thanks for recycling, every little bit helps! Fortunately I won’t be around in 2050 when there is more plastic in the ocean than fish…
Mola mola, or Ocean Sunfish picture from Wikimedia Commons
10 Mola Mola, or Ocean Sunfish, Facts: The fish so nice they named it twice!
1. Mola mola are known because of their unusual shape: an upright flattened disk, tapered top and bottom fins between body and tail, and small black eyes halfway between its small pectoral (side) fins and round mouth.
2. Mola Mola Sunfish got their name because they like to lay down on their sides and sun themselves at the surface. They do this to stay warm and to get rid of parasites (seabirds eat those).
3. Mola Mola are related to pufferfish, porcupinefish, and filefish (same Order Tetradontiformes).
4. Mola Mola lack a swim bladder so they swim constantly (or move fins side-to-side to hover).
5.Mola Mola are the largest bony fish in the ocean! Average length 5.9 ft (1.8m), 8.2 ft (2.5m) fin-to-fin Max length 10.8 ft (3.3m), 14 ft (4.2m) fin-to-fin Weight range 545 lbs (247kg) to 5,100 lbs (2,300kg)
6. A single Mola Mola can host up to 40 species of parasites. It gets rid of them by sunning at the surface and having seabirds eat the parasites, or by cleaner fish and other fish eating the parasites at cleaning stations, or by breaching up to 10 ft (3m) out of the water.
7. Ocean Sunfish eat mainly jellies, but also eat salps, squid, crustaceans, small fish, fish larvae and eel grass.
8. Mola Mola can swim to depths down to 2,000 ft (600m). Mola fry: notice the spikes all around it: photo by G. David Johnson
9. Ocean Sunfish can grow to 60 million times their birth size (0.1 in, 2.5mm), a record for vertebrates! As fry (babies that are part of the plankton), sunfish have spines all around their body that they outgrow.
10.Enemies as young include bluefin tuna and mahi mahi, as adults sea lions (who often bite off their fins and play with them), killer whales, sharks and humans (caught to eat or as by-catch).
What type of fish is Dory from the Finding Nemo and Finding Dory movies?
What type of fish is Dory and her parents?
Dory and her parents are Yellow Tail Blue Tangs or Blue Hippo Tangs or Pacific Blue Tangs or Palette Surgeonfish. Her Mom’s name is Jenny and her Dad’s name is Charlie.
What type of fish are Marlin and Nemo?
They are Ocellaris or False Percula Clownfish or Clown Anemonefish.
What kind of sea turtles are Crush and Squirt?
They are Green Sea Turtles, one of 7 species of sea turtles. Green sea turtles were named green for the fat on their body, not the color of their shells or skin.
What kind of ray is Mr. Ray?
He is a Spotted Eagle Ray. Fortunately he’s not the type of Stingray shown migrating in the movie or else he’d be leaving his students behind! There is a specific kind of ray known as the Golden Cownose Ray that may migrate in groups of up to 10,000!
What kind of whale is Bailey?
Bailey is a Beluga Whale. Belugas are often called the “canaries of the sea” because of their vocalizations. Their (squishy) fat-filled melons (heads) are supposed to help with echolocation, the sonar that many whales use in the ocean.
Destiny is a Whale Shark. It’s cute that she and Dory knew each other and can speak whale, but Destiny is a Shark, not a Whale! She’s the largest shark in the ocean, but only eats tiny plankton with her cavernous mouth. Whale Sharks do have poor eyesight because their eyes are so tiny compared to their bodies, but they are not clumsy. Anyone who has snorkeled with Whale Sharks know they can turn on a dime to avoid swimming into you!
What kind of octopus is Hank?
Hank is a generic octopus. Octopuses are masters of camouflage and many can turn orange like Hank. He is actually missing an arm, so he’s a “septopus.” In real life, the octopus would grow any missing arms back. There are so many neurons in a severed octopus arm that it can move and hunt on its own!
What kind of Sea Lions are Rudder and Fluke?
Sea Lions are probably California Sea Lions. I’m guessing they are California Sea Lions because part of the movie takes place off of California. If they were both male, then they could be found off of Pier 39 in San Francisco where bachelor males hang out and entertain tourists.
What kind of Sea Otters are the baby Sea Otters?
The baby Sea Otters are oh so cute! They are probably Southern Sea Otters, mainly found off the California coast. Sea otters don’t stand up on their hind legs like river otters do, and they couldn’t climb up the poles to the freeway! In some press pictures, it looks like there are baby sea otters in a group. There would never be a group of babies together because a wild Sea Otter pup stays with Mom 24/7 and they rarely socialize with other mother/pup pairs. Even surrogate Sea Otter Moms at the Monterey Bay Aquarium only take care of one pup at a time!
What type of bird is Becky?
I speculate Becky is a Pacific Loon. Loons may mate for life! They eat mainly fish, crustaceans, and insects.
How and why do fish school? First off, an aggregation of fish is when a bunch of fishes are together. Shoaling is when a group of fish come together for social reasons. It is more specifically called schooling when the fish also move together in coordination. Half of all fishes shoal at one point during their lives, and one quarter of fishes shoal their whole lives.
There are a multitude of reasons why fish school. These include safety in numbers , easier to find food, swimming more efficiently and easier to find potential mates. Schooling behavior confuses potential predators, which cannot focus just on one fish to catch.
Schooling takes coordination, as each fish senses its position in relation to the other fishes. All fish have a lateral line around their bodies that help. There are tiny holes with sensitive hairs in them in the lateral line.
Most fishes don’t school when it is dark, so they are dependent on their eyesight.
According to some scientists, how they school is dependent on their genes. It’s not a learned behavior. Scientists did experiments on some small fish (see here for details) and cross bred individuals that preferred schooling to those that didn’t. The results told the scientists that there are parts of the fishes’ genome associated with schooling.
Another mystery is how fish somehow know when they are with fish that look like themselves so they can school together. They don’t recognize themselves in a mirror like more intelligent animals, so how do they do it? An odd fish out in a school increases its chances that it’ll be seen by a predator.
They may use their senses: sight, smell (pheromones), and sound. But otherwise a Google search only comes up with conjectures.
What questions do you have about fish? I’ll cover them in future posts.
Red-bellied Piranha photo by wikimedia commons Karelj
10 Fascinating Piranha Fish Facts
1. All Piranhas fish live in tropical freshwater rivers, lakes, and lagoons in the northern half of South America.
2. There are between 30-60 species of Piranha fish.
3. Piranhas’ teeth are triangular shaped and as sharp as sharks’ teeth.
4. Only 3 species of Piranhas are considered dangerous to humans:
a. Black shoulder Piranha
b. Red-bellied Piranha (average sized at 13 inches and 3 pounds)
c. Sao Francisco Piranha (largest at 24 inches and 13 pounds)
5. There have been no fatal attacks on humans as Piranhas only bite fingers, toes and chunks of legs and hips.
6. Piranhas live 10-25 years.
7. Shoals of up to 1000 Piranhas stay together to survive, not necessarily to hunt.
8. Most Piranhas are omnivores that eat meat (scavenge mainly), seeds and fruits.
9. Predators include caimans (a small crocodile), river otters, larger fish, and herons (a large bird).
And the last fascinating piranha fact is:
10. When Piranhas attack a large animal, they eat the flesh and muscle in seconds, and leave only the skeleton.
