What makes sea food have similar smell?

I never ate fish, I always disliked the smell and had a little bit of trauma with my father forcing me to eat it while I was a kid. I had two experiences:

Some years ago, I tried sushi. It doesn't have a strong smell of fish and I found it edible. But there is a very faint smell of fish.
Some days ago, I bought some chips made of Nori algae. They were vegan chips and yet, I felt the same soft smell of fish.

I conjectured that perhaps, part of this smell is common to all things in the sea. Lately, I decided to do indoor farming and when studying about fertilizers, I heard someone saying that "certain fertilizers with phosphorus have a smell of fish and that the sea is rich in phosphorus" so, this seems to be my first guess. I understand that my question is a bit vague.

fish smell

Best Answer

The American Society for Nutrition explains it thus:

The answer has to do with some interesting physiology unique to sea creatures.Water in the open ocean is about 3% salt by weight, but the optimal levels of dissolved minerals inside an animal cell is less than 1%.In order to maintain fluid balance, ocean creatures must fill their cells with amino acids and amines to counter the saltiness of seawater. Ocean fish tend to rely on trimethylamine oxide (TMAO) for this purpose.

Now this compound does not in itself have a particularly pungent odour, however:

The problem is that when fish are killed, bacteria and fish enzymes convert TMAO into trimethylamine (TMA), which gives off the characteristic “fishy” odor.This smell can be reduced in two ways.TMA on the surface of the fish can be rinsed off with tap water.Treating the fish with acidic ingredients such as lemon, vinegar, or tomato can also cause TMA to bind to water and become less volatile.Thus the odor compounds do not reach the nose.

This trimethylamine is something that is produced in small quantities by our own gut microbes, and usually is no trouble when kept under control - some however are unfortunatley prone to "Fish Odour Syndrome".

I am not able to find any definitive evidence for the reason that nori smells of fish, however, an uncorroborated suggestion behind the scenes on a Wikipedia wiki page states this:

Please. Fish smells of algae, not the other way around! For the same reason DHAs are not "fish oils", but "algae oils".--Rfsmit

_{Bolding Mine}

As they are so ubiquitous in nature it would seem likely that the bacteria that convert the TMAO into TMA and make the smell would be present on the algae as well as in the fish and in our own guts.

Conclusion.

I'd claim that the bacteria and what it eats and it's waste products are to blame for the similar smell: it would seem to be the case that Japanese Nori (There mis-classified as genus Porphyra) contains amino acids and nutrients not inconsistent with the culprit bacteria growing on it (As it also like fish flesh). As I say I can not offer anything definitive.

Pictures about "What makes sea food have similar smell?"

What makes sea food have similar smell? - Silhouette Dusk falling Rapidly

What makes sea food have similar smell? - A Blanket on Brown Sand Near Body of Water

Why does all seafood smell the same?

Not all fish are equally smelly, either. Hotchkiss says that the enzyme is most common in "the flesh of fin fish, especially cold-water, surface-dwelling ocean fish." So if you really hate smelly fish, avoid fish from the ocean like haddock or cod and opt for something like freshwater salmon or trout.

What causes seafood smell?

The problem, or stink, arises when fish are killed and bacteria and fish enzymes convert TMAO into trimethylamine (TMA), which gives off the characteristic fishy odor. This chemical is especially common in the flesh of cold-water surface-dwelling fish like cod.

What should seafood smell like?

Fresh fish should taste and smell that way: fresh, briny and sweet, not musty, yeasty, bitter or fishy. The texture should be resilient, firm and smooth. Older fish that has become mealy or mushy tastes bad and smells worse.

What gives seafood taste?

Much depends on whether a fish lives in freshwater or saltwater: saltwater fish counterbalance the salinity of their environment by producing flavor-giving amino acids, including sweet-tasting glycine and savory glutamate, that milder-tasting freshwater fish lack.

Have You Noticed You Have An Odor After Eating Fish?

Sources: Stack Exchange - This article follows the attribution requirements of Stack Exchange and is licensed under CC BY-SA 3.0.

Images: Lucas Andrade, Lucas Andrade, Asad Photo Maldives, Olya Kobruseva