Questions tagged [marine-biology]

The study of organisms that dwell in the ocean or brackish waters.

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3 votes
0 answers
21 views

What determines the color of the air sac of a Portuguese man o' war?

I know that the Portuguese man o' war is a colonial organism composed of many "zooids", one of which is the pneumatophore, which essentially serves as a flotation device for the whole colony....
2 votes
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Identifying fish or shark jaw bone

I found this on the beach of coastal southern Maine in early March. The teeth are not a single row and lighter is for size comparison
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Identify item found on Naples, FL (USA) beach. Hard like a shell but with no opening

Very hard and translucent. Very sharp point.
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1 answer
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What species is this white thin shell? Santa Cruz, California

These shells (see in green circle) are empty inside which look like very flat marble donuts/coins. The small ones are like dollar coins; big ones can be cup coaster-sized. It has beautiful five-fold ...
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1 vote
1 answer
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How are ray-finned and lobe-finned fish related in terms of their evolutionary history?

I'm trying to trace human evolution back to the first eukaryotic cells (as a tool to research the evolution of various bodily systems), and I understand that lobe-finned fishes are considered a key ...
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Please identify hard hollow structure found on beach

This washed up on the shore in NJ last week. It looks like a molar but I cannot find anything similar 1.75” across about 1/2 high. It has a weird indent too
2 votes
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Origin of holes at 800 m depth in the Mediterranean

From 8 to 12 small 2-3 cm holes in the bottom mud are forming rounds with a diameter of 20-40 cm. No tentacles or other body parts have been observed. Mediterranean sea, 600-1000 m. What are they?
8 votes
1 answer
173 views

Identification of a strange skull

My father is a fisherman in the Baltic sea, and he has found this very strange skull. I would like to know to which animal it belonged. Can someone help identify it?
17 votes
1 answer
2k views

What's this stuff that looks like white chainmail armor growing on giant kelp?

I found some giant kelp coated with a material that is white, smooth, and forms a chain-mail pattern with small black oblong lumps in between the links. It feels pretty hard but not stiff (the kelp ...
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How do algal blooms deplete oxygen? [duplicate]

How do algal blooms deplete oxygen and kill marine life? Don't they release, not consume oxygen as seaweed does? Different types of algae function differently in that respect, don't they? If they need ...
3 votes
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How does Anabantoideis' labyrinth function? What does it look like?

Anabantoideis are fish with an organ that allows them to take oxygen directly from the air outside of water. However, I cannot find much on how this functions, nor can I find any clear image of what ...
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Marine invertebrate San Juan Islands, WA, USA

I noticed a green-colored marine arthropod in harbor in the US San Juan Islands (early July 2022, around noon), specifically Haro Strait, and took several pictures from the dock. The bug was ...
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What species does this shell belong to?

What species of mollusc shell is this? Found this on the east coast of India, RK Beach, Vishakhapatnam Small enough to fit in a hand. Looks like a flower - is it a broken shell?
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1 answer
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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

Does anyone know what this is? I know this is not a land mammal because [details needed]. Unknown skull found under rock at beach. No sign of eye sockets or jaw with teeth. I have no idea what this ...
3 votes
1 answer
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What is this marine creature? Is this a fossil?

Found this on a beach on the East coast of India - Vishakhapatnam, India Is this a fossil? A coral? Its small enough to fit in my hand These tunnel-like structures are hard like rock/calcified ...
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10 votes
1 answer
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Can whales send each other [3D] images?

Russell Arnott, apparently an oceanographer, who currently works as a project manager at the Sainsbury Laboratory, Cambridge University (UK), wrote in his piece Whales and Waves (2016, p.2): New ...
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What unmanned monitoring techniques are available to measure coral reef health?

Most biological data for coral reef monitoring are collected by human observers. This could be resource-intensive for long-term studies and thus hard to maintain consistency on large spatial scale. ...
7 votes
1 answer
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Why does biomagnification of mercury occur more in large fish?

I love tuna so this question has been bugging me senselessly. I am aware that larger fish tend to have more mercury concentration in their flesh than their prey, however, I don't understand how this ...
0 votes
1 answer
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What types of sounds do sperm whales produce?

Sperm whales produce echolocation clicks, what are the other types of clicks and other sounds they can produce?
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1 answer
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How can this coral survive with little sunlight?

Forgive me if this question is off topic, but I’ve seen similar questions so I think it should be on topic. I’m at the beach currently, and I was looking in tide pools for interesting things. I found ...
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Which varieties of Aurelia aurita do not have a polyp phase?

According to this "In some Aurelia aurita, the polyp stage does not exist.", but they don't cite anything. Is there a resource detailing life cycles of various jellyfish or do I have to find ...
1 vote
1 answer
187 views

Why do blobfish become bloated when they are brought to the surface?

There are several things that can happen to deep sea creatures that are brought up to the surface, but none of them explain why the blobfish becomes deformed. Blobfish don't have swim bladders, so ...
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5 votes
2 answers
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What is this large, lively barnacle?

Yesterday I found this creature in a rocky cove in central California, around mid tide (+ 3 feet). It's about 3-4 inches long. At first I thought it was dead, but it closed its mouth when I removed ...
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Cortisol in sharks

Is there an established method for measuring stress hormone levels, like cortisal, in sharks? If so, is it known what levels of such hormones create significant detrimental effects like decreased ...
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What are marine fungi like?

Particularly, what is their mycelium like and where exactly do they grow it? I imagine that their spores travel though water same as terrestrial fungi travel through air until they stumble upon solid ...
1 vote
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What protein(s) bind together the calcium carbonate tiles in abalone shell to give it strength?

The articles that I've been able to find on the structure of abalone shells mention that they consist of calcium carbonate plates connected by proteins, but don't name the proteins. These proteins are ...
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4 votes
1 answer
107 views

Please, help identify this sea worm

It was found in Malta, in a puddle by the sea. It left a lot of tiny hair on the shoes (which we removed thoroughly without touching them). I didn’t have any coins with me so I put keys for scale.
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2 votes
1 answer
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Why do fish and marine mammals need special low density adaptations for buoyancy?

When one reads about fish and marine mammals, it is always said that for example blubber of marine mammals helps them with buoyancy because it is so low density and similarly for example sharks have ...
7 votes
1 answer
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Deflated bag-like species on beach: Identification

I encountered this on a beach in Chandipur, along the Bay of Bengal in India. Quite a few of them were scattered in different locations. Identification of this controversial object is appreciated.
4 votes
1 answer
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What are the current theories on how baleen whales make whale song?

Wikipedia does not provide many details1 on how baleen whales produce 'whale song', saying it's still a mystery. The linked Gizmodo article provides these paragraphs: Humpback whales, for example, do ...
1 vote
1 answer
310 views

does more biomass mean more energy?

I am a high school student and I am very confused about ecological pyramids. My textbook states that the biomass of zooplankton in an aquatic ecosystem is more than that of phytoplankton (I don't know ...
3 votes
1 answer
123 views

Can anyone identify this fish?

I saw it in the sea very close to the beach in front of Starfish Hotel in St Lucia. It had some spines along its back and it seemingly had fins on each side that split open into 4. It used its front ...
3 votes
1 answer
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Can Shark bodies be preserved?

Under normal conditions, Shark bodies, which are made of cartilage are not preserved and only the teeth can only be preserved. I searched whether Shark bodies can be preserved in ice and I got this ...
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2 votes
1 answer
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Could you identify the species of this animal attaching to a fish in the Aegean Sea?

While wading within a few meters from the shoreline today, I observed and was observed by a number of curious fish. One of them had a blackish attachment, which was reminiscent of a small aquarium ...
1 vote
0 answers
177 views

Why is this Sea Turtle yawning?

I found this video online of a Green Sea Turtle lying down on a sea sponge and letting out a big yawn. Here is a screenshot of the video, just incase the link doesn't work: As far as I understand, ...
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-1 votes
2 answers
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Could the problem of overfishing be solved by throwing fertilized fish eggs at the right place and deepness into the sea? [closed]

I hear sometimes about over fishing and I wonder if the following idea could help to solve the problem. My idea is to throw fertilized fish eggs at the right place and deepness into the sea. These ...
3 votes
0 answers
65 views

Octopus out of water

I was watching a YouTube video where a guy saw an octopus out of water. It was far from a puddle, and looked like it was struggling. He decided to help it get to the next puddle, so he picked it up ...
1 vote
1 answer
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Have orcas ever been observed to be eaten by another species?

Orcas are well known to prey on just about everything that lives in the ocean, even including great white sharks. Yet in a lot of cases I know that the food chain is not unidirectional, there are many ...
6 votes
1 answer
42 views

By what mechanism do cephalopods regrow limbs?

As far as I can tell, there are two types of limb regeneration: epimorphosis and morphallaxis. Epimorphosis is used by animals such as amphibians and various phyla of worms, while morphallaxis is used ...
2 votes
1 answer
340 views

Please identify this bone found on the beach

I've found it on the beach in Çanakkale, Turkey. Width 7.5 cm, height 5 cm. Inner hole dimensions are 2.5 cm x 3 cm.
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3 votes
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Do jellyfish have extra energy reserves for emergencies (a "fight or flight" response)?

My friend is writing a story about jellyfish, and we couldn't find out if jellyfish have the equivalent of a "fight or flight response" or an adrenaline rush. In other words, do they have ...
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Maximum Allometry of aquatic mammals omitting Kleiber's Law

As far as I understand, blue whales cannot get any physically larger due to the extremely demanding caloric intake it has on consuming large quantities of krill, not due to any other physiological ...
1 vote
1 answer
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Can someone identify this jellyfish?

Recently, I saw this video but I couldn't find out if it's CGI or if it's an actual jellyfish. If it's real, what explains its beautiful bioluminescence pattern? And could the output from the ROV ...
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Pearl formation process: what is it called? How does it work?

I have heard a pearl is a disease of oysters. Astonished by the statement, I searched a bit [1] and I discovered that it is really a protection mechanism of the oyster. I know this defense mechanism ...
-1 votes
1 answer
54 views

Is insect farming more efficient than shrimp farming? [closed]

Insect farming is sometimes advertised as the way to feed the growing global population with animal protein in a way that is more efficient (in terms of protein yielded/feed consumed) than growing ...
1 vote
2 answers
118 views

Do whales ever just hang out on the surface breathing?

You only ever hear of whales surfacing for a brief second to exhale/inhale before they dive back down. But do they ever just stay at surface level, laying there with their blow hole up in the air, ...
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4 votes
2 answers
187 views

Why is the consumer/producer biomass ratio higher in the oceans?

According to Bar-on et al. (2018) (see figure 2), the terrestrial consumer/producer biomass ratio is 20/450 while the marine consumer/producer biomass ratio is 5/1 (in Gton of carbon). Why is the ...
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2 votes
2 answers
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Do fish depend on plants for survival?

As far as I know, all land life depends on plants for survival. Plants convert sunlight to energy using photosynthesis, herbivores consume plants, and carnivores consume herbivores. All the energy is ...
1 vote
0 answers
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Identification of Ulva lactuca

I am trying to find an ID guide that I can use to identify macroalgae. I specifically want to differentiate between Ulva species.
1 vote
1 answer
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Is life in the open ocean homogenously spread?

Obviously around land masses or in shallow water where reefs and coral may grow, life is diverse and numerous. But how spread out is sea life in the open ocean (for example, half-way between Hawaii ...

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