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45 votes

I am trying to identify this bone I found on the beach at the Delaware Bay in Delaware. It is 2 1/2 inches wide and 1 1/2 tall

It's a pharyngeal tooth from a large fish like a drum or a parrot fish. The pharyngeal jaws are for grinding and also contain a pharyngeal mill, where larger and smaller teeth grind coarser and finer ...
bandybabboon's user avatar
  • 10.4k
36 votes
Accepted

What is this strange sea creature we found on the beach?

You have a Dosima: Also known as a Buoy Barnacle. A gallery of observations of these can be found here: https://inaturalist.ca/taxa/462188-Dosima/browse_photos They are found in the coastal UK and ...
JimN's user avatar
  • 2,014
28 votes

A weird-looking fish with a shield

This is a species in the Peristediidae family, commonly called armored searobins or armored gurnards. found in deep waters around the world, with most species in tropical regions. They are related to ...
theforestecologist's user avatar
25 votes
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Identify blue/translucent jelly-like animal on beach

By-the-wind sailors This appears to be Velella (a monospecific genus), commonly referred to as by-the-wind sailor. More specifically, this is Velella velella, and is also less commonly referred to ...
theforestecologist's user avatar
22 votes

What exactly is this small puffer fish doing and how did it manage to accomplish such a feat?

A tiny Japanese puffer fish creates a grand sand sculpture on the featureless seabed by using his fins to dig furrows. He uses this to attract the attention of passing females. Why do puffer ...
brazofuerte's user avatar
  • 1,582
21 votes
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What strange jelly-like thing is shown in the photo?

I agree with @Gerardo-Furtado's comment that what you most likely have here is a colonial tunicate (or sea squirt) from the genus Botrylloides. According to images and information available via the ...
theforestecologist's user avatar
20 votes
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Identification of colorful jelly-like marine creature

You've found a sea anemone, a cnidarian of the Order Actiniaria. In this case, the anemone is closed and thus hiding its characteristic tentacles (likely as a form of protection while "out to dry"). ...
theforestecologist's user avatar
20 votes
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Inexperienced divers damage coral, but parrot fish eating coral doesn't do damage?

You are absolutely correct in regards that marine life does cause damage to corals. In particular, parrotfish have been found to play an important role in regulating the biodiversity of coral reefs ...
Sudachi's user avatar
  • 1,017
18 votes
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What's this stuff that looks like white chainmail armor growing on giant kelp?

That looks like it could be the lacy crust bryozoan (Membranipora membranacea). That bryozoan is an epiphytic animal whose native range includes the Pacific coast; it does not feed on the kelp, but ...
tyersome's user avatar
  • 5,598
16 votes

What exactly is this small puffer fish doing and how did it manage to accomplish such a feat?

This "nest" is created by a male pufferfish for both courtship and for rearing young. The male puffer fish uses its body and fins (a combination of pectoral, anal, and caudal -- see here) to ...
theforestecologist's user avatar
16 votes
Accepted

Why does biomagnification of mercury occur more in large fish?

Bioaccumulation occurs when organisms aren't able to excrete/eliminate/metabolize something as fast as they take it in. The specific circumstance of predators higher on the food chain accumulating ...
Bryan Krause's user avatar
  • 45.9k
12 votes

Why are the bodies of the Risso's dolphin covered in scratches?

[ From Jefferson et al. 2015, Marine Mammals of the World, 2nd edition, p 212: "At sea, the best identification characteristic is the coloration and scarring. Adult Risso's dolphins range from dark ...
Variegated Meadowhawk's user avatar
11 votes
Accepted

Help identify these (two) fishes - Netherlands

The second fish looks like a rock gunnel (or Butterfish; Pholis gunnellus). This is an eel-like fish found in the intertidal and subtidal zones of the North Atlantic. Interestingly, the rock gunnel ...
theforestecologist's user avatar
11 votes

What sea animal is this?

It's probably a dugong, based on the location, lack of a dorsal fin, split tail, lack of a blowhole, and narrowing of the snout. The prominent vertebral column looks unusual, but that might come from ...
Bryan Krause's user avatar
  • 45.9k
11 votes

Found this under a rock at the beach, removed it carefully and couldn't find any other bones, must be a marine mammal of some sort

A reasonable match for many features, bearing in mind the incompleteness of the skull is that of the South African Fur Seal (AKA. brown fur seal, Australian fur seal).: Carolyn Stewardson, Tania ...
Jiminy Cricket.'s user avatar
10 votes

How long can an octopus survive out of the water?

Found an octopus today which had attached itself to a rock covered in algae during high tide and had failed to swim back out with the receding tide. We found it at low tide, this means it must have ...
Xavi's user avatar
  • 101
10 votes
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Deflated bag-like species on beach: Identification

Sea cucumber. There are over 1700 known species, all inhabiting the sea-bed, mostly in deep waters, but can be found on the continental shelf in many areas. An echinoderm (alongside sea-urchins and ...
Jiminy Cricket.'s user avatar
10 votes
Accepted

Identification of a strange skull

Looks like this is a neurocranium of a tuna or a similar species (dorsal view on this site). I've also found a very similar picture of Atlantic blue tuna from USA, which seems to support that this is ...
BassAstral's user avatar
9 votes
Accepted

Can jellyfish sting outside of water?

Short answer Jelly fish can sting out of the water and even when they are considered to be dead. Background I do not have detailed scientific literature available. However, popular sources generally ...
AliceD's user avatar
  • 52.5k
9 votes
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The colour of aquatic plants found deep under oceans

You're right that certain wavelengths of light are more capable of penetrating deeper depths of water. However, it turns out, blue light typically travels to deeper depths than all other visible ...
theforestecologist's user avatar
9 votes

ID a shell from Puerto Rico

This is the shell of a marine mollusk called a chiton. They are also sometimes known as sea cradles or "coat-of-mail shells", or more formally as loricates, polyplacophorans, and ...
theforestecologist's user avatar
9 votes
Accepted

CO2 availability to phytoplankton in oceans and climate change impacts

Short Answer I do not believe that CO2 will become less available to phytoplankton on a global scale in the foreseeable future. Instead, I believe that rates of increasing concentrations of CO2 (and ...
theforestecologist's user avatar
8 votes
Accepted

What is the largest species of polychaete?

According to the Smithsonian: The longest of all known polychaetes was found in Port Jackson, Australia. It was a member of the family Eunicidae, consisted of approximately 1,500 segments and was ...
theforestecologist's user avatar
8 votes

Do fish depend on plants for survival?

Yes, photosynthesis provides nearly all of the ocean's biomass and energy. The best is to study oceanic food chains and webs. It looks like there aren't enough plants in the ocean because they don't ...
bandybabboon's user avatar
  • 10.4k
8 votes
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Why do blobfish become bloated when they are brought to the surface?

Blobfish don't have swim bladders, they also don't have a lot of other things we associate with surface animals, like much of a skeleton or many muscles. This is fine under the extreme pressure they ...
John's user avatar
  • 14.7k
8 votes

What are these semi transparent pill-shaped things in the Mediterranean Sea?

Quick guess based on your low-quality photo: Reminds me of a pyrosome, a tube/rod-shaped, free floating colonial tunicate. According to here, Pyrosoma atlanticum is the only species found in the ...
theforestecologist's user avatar
7 votes

Why is oxygen used up in eutrophication?

Algae produce $O_2$ in the upper layer of water but when they die they stop producing $O_2$. They sink to the seafloor and most get decomposed by bacteria on the seafloor. In this process, bacteria ...
Mud Warrior's user avatar
7 votes
Accepted

Organic battery?

I don't have the math at hand for the actually energy efficiency, but let's just start from the storage capacity. Basically, an electric eel wouldn't make a very good battery. They could be a decent, ...
Bryan Krause's user avatar
  • 45.9k
7 votes
Accepted

Do fish depend on plants for survival?

Short answer All marine life needs energy to survive and reproduce. "Heterotrophic" organisms get their energy from eating other organisms and digesting the molecules of their tissues for ...
theforestecologist's user avatar

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