#sealcore

📖 See end of this post for two book recommendations 📖

DISCLAIMER: This post is NOT intended to offend anyone, and is meant for EDUCATIONAL purposes only. What the reader chooses to do and how they react is ENTIRELY up to the reader. 👍🏻

Greetings fellow fish eaters!

Today I present y’all a selkie-coded guide to choosing the best fish for frequent feasting, avoiding mercury and microplastic poisoning, and why we should side-eye anything that came from a fish farm.

✦ First: What even IS mercury and why is it in our dinner?

Mercury is a naturally occurring heavy metal (yes, it’s in the earth’s crust, volcanic eruptions release it, forest fires release it, etc.).

Mercury also comes from coal-burning power plants and gold mining. It turns into methylmercury in water, which is the neurotoxic form that builds up in living things.

The rule of the sea: the bigger, older, and higher up the food chain a fish is, the more mercury it has accumulated. Apex predators = mercury magnets.

✦ Selkie Approved Low-Mercury Fish (eat these all you want)

Atlantic mackerel (not king mackerel—king is high!)

Sardines

Herring

Anchovies

Wild-caught Alaskan salmon (basically the selkie national dish)

Pacific jack mackerel

Trout (freshwater, usually very low)

Shad

Mullet

Butterfish

Smelt

Fresh/snap-frozen pole-and-line-caught skipjack tuna (light chunk, not albacore)

Basically: small, fast-growing, short-lived fish = very little time to collect mercury.

✦ Fish to Eat Rarely (or never, if you’re full selkie and eat fish daily)

Swordfish

Bigeye tuna

King mackerel

Marlin

Shark (tbh we don’t eat them they eat us lol)

Tilefish

Orange roughy (also these poor things are ancient - some are 150 years old. Leave them be.)

Albacore/white tuna

Spanish mackerel (Gulf of Mexico)

✦ Why Wild Caught is BETTER than eating Farmed Fish

Farmed fish are basically aquatic feedlot cows:

Crowded → disease → constant antibiotics

Fed processed pellets made of wild fish (it takes 3–5 kg of wild fish to grow 1 kg of farmed salmon.

Higher levels of PCBs, dioxins, and other persistent pollutants because of that feed

Often dyed to look pink (wild salmon are pink from eating krill; farmed ones get it from chemicals)

Escapes interbreed with wild populations and wreck genetics

Sea lice epidemics that torture wild salmon nearby

If we wouldn’t eat something raised in a warehouse swimming in its own poop, don’t eat farmed fish. Simple.

⚠️ WARNING about Microplastics ⚠️

✦ What are they?

Tiny plastic bits (<5 mm) and nanoplastics (<1 μm) are now in literally every corner of the ocean.

This plastic comes from man made plastic products that can be found in everything from toothpaste, laundry detergent, soap, cosmetics, and even food preservatives - disturbing fun fact: in the USA nearly all brands of pickles contain a microplastic preservative called Polysorbate 80.

If you’d like to help keep the sea and your body free of microplastics, always check the ingredients and do not purchase if the ingredients list a word that starts with “POLY”.

✦ Who in the sea Absorbs these microplastics?

In the sea, filter-feeders and bottom-dwellers eat the most because that’s where the plastic sinks or floats in the water column.

We’re finding 100–600 pieces per individual fish in some studies. Mussels in the Arctic have hundreds of pieces each.

✦ How are microplastics absorbed?

Once in the body of any living organism, polymers (plastics) are stored in lipids (fats) in the body, and it’s difficult/near impossible to remove them.

What becomes the hazard factor is primarily related to reproduction, when fats stored away in the body are used to help a fetus grow, and the toxins absorbed by the fetus can cause many developmental issues, and sometimes result to premature death.

This is often the case why the first born calves of whales do not survive as whales absorb a lot of microplastics through the krill they eat (krill eat algae and other small microscopic organisms that feed on microscopic matter - including plastics).

Mixroplastics aren’t just a concern for whales, but for all living creatures who reproduce. If we want a future where life on earth still exists, then we must stop using products with plastic and spread the word.

✦ Why We Shouldn’t Completely Blame the Corporates

We cannot blame the manufacturers alone, because 90% of them have no clue the materials they use to make awesome products are actually harming everyone including themselves.

This is why educating everyone about microplastics is so important so we can find better ways to make the same products but with healthier ingredients.

✦ So What Fish Can we Eat?

LOW microplastic risk – your safest daily bites

Wild Alaskan salmon (they eat clean squid & krill high in the water column, far from coastal plastic soup)

Atlantic mackerel & herring (pelagic, fast swimmers, shorter life → less time to accumulate)

Sardines & anchovies (small, live near surface, poop out plastics fast)

Smelt, freshwater trout (if truly wild and from clean lakes/rivers)

✦ Medium risk – fine sometimes

Cod, haddock, pollock (bottom-feed a bit, plus trawling stirs up plastic-laden sediment)

Skipjack tuna (open ocean, but they live longer than sardines)

✦ High risk – basically eating the Pacific Garbage Patch in fish form

Farmed salmon & tilapia (fed pellets that often contain microplastics from processed trash fish + tanks concentrate plastics)

Bottom-dwellers: sole, flounder, farmed shrimp

Shellfish (oysters, mussels, clams) – filter thousands of litres of water a day. They are the ocean’s vacuum cleaners. Delicious, but plastic city.

Anything from heavily polluted areas (Mediterranean, South China Sea, etc.)

✦ Selkie Microplastic Hacks

1. Stick to pelagic (open-ocean, swimming) fish over benthic (bottom-hugging) ones.

2. Smaller = usually cleaner. A sardine has had 1–2 years to eat plastic. A 30-year-old tuna has been marinating in it since the 90s.

3. Wild >> farmed every single time. Farmed fish eat plastic-contaminated feed and live in plastic-rich water.

4. Gut & clean thoroughly – a lot of microplastics hang out in the digestive tract (yes, this is why some cultures only eat fish heads or fillets).

5. Eat higher in the water column species: mackerel, herring, sardines, salmon.

★ TL;DR Cheat Sheet (now accounting for BOTH mercury AND microplastics)

DAILY / NO WORRIES

- Sardines

- Herring

- Anchovies

- Atlantic mackerel

- Wild Alaskan/Icelandic/Faroese salmon

- Smelt

ONCE OR TWICE A WEEK

- Wild cod/haddock/pollock (gut them!)

- Pole-and-line skipjack tuna (light chunk)

ONCE A MONTH OR LESS

- Shellfish (if you love them, maybe boil/steam and discard the broth)

- Bottom fish (sole, flounder)

- Anything farmed

NEVER (mercury + plastic double whammy)

- Farmed salmon/tilapia/shrimp

- Swordfish, shark, big tuna species

- Mussels/oysters from urban coasts

✦ Quick Selkie Rules for Safe Feasting

1. Eat low on the food chain

2. Eat small & young (a 2-year-old mackerel has 1/50th the mercury of a 20-year-old tuna)

3. Prefer wild-caught from cold, clean waters (Alaska, Iceland, Faroe Islands, etc.)

4. Check your regional advisories - some local fish are contaminated by poor water quality

5. If you’re pregnant, planning to be, or a selkie pup, be extra strict - methylmercury and microplastics loves developing brains and bodies

Stay safe out there, spread knowledge, help others, and happy fish eating! 🐟

★ P.S. If you’ve gotten this far and are wondering how I know all this stuff, PLEASE read these two books that I studied in college for a class on oceanography.

These two books, “The Ocean of Life”, and “Cradle to Cradle”, taken with a grain of salt, will open up the mind to the truth about our oceans (and the manufacturing industry), might give the reader an existential crisis, but in the end will help the reader understand the importance of why we must continue educating ourselves and others, along with find innovative ways to improve the health of our planet. Inspire us to do our due diligence abolish pollution if we want life on Earth to continue, whilst have the prospect of a future where sustainable abundance is possible for all species. 📖👇🏻

Nah that’s a harbor seal - could even be a selkie

And while harbor seals may have “rosettes” and spots that are “leopard like” but leopard seals are VERY different than harbor seals 🦭

For anyone wondering what the differences are between these two magnificent species of seals, here’s a brief essay:

Size and Physical Appearance

Harbor seals: Relatively small and compact. Adults are typically 5–6 feet (1.5-1.8 m) long and weigh 180–285 pounds (80–130 kg), with males slightly larger than females

They have a spotted or mottled coat (gray, brown, or tan with darker spots), a rounded head, and a more “cute” or approachable look

Leopard seals: Much larger and more elongated/serpentine. Adults range from 7.9–11.5+ feet (2.4–3.5+ m), with females often larger than males (up to ~12.5 ft / 3.8 m)

They weigh 440–1,320 pounds (200–600 kg). Their coat is dark gray/black on the back with distinctive lighter spots (hence the “leopard” name), a large head, powerful jaws with prominent teeth, and a more streamlined, predatory build

Leopard seals are apex predators built for power and speed (up to ~24–25 mph / 38–40 km/h underwater), while harbor seals are more agile but far less imposing

Habitat and Distribution

Harbor seals: Found in temperate and subarctic coastal waters of the North Atlantic and North Pacific (e.g., along US coasts, Alaska, Europe)

They haul out on rocks, beaches, reefs, sandbars, or ice in protected areas and are commonly seen near human-populated coastlines

Leopard seals: Primarily Antarctic and subantarctic, associated with pack ice (pagophilic)

They are solitary and range across the Southern Ocean, with occasional vagrants reaching southern Australia, South America, or New Zealand

They prefer ice floes and areas near penguin colonies

Harbor seals live in milder, coastal environments; leopard seals thrive in extreme polar conditions with thick blubber for insulation

Diet and Hunting

Harbor seals: Primarily fish eaters (generalist but focused on fish, plus shellfish, squid, and crustaceans)

They forage in shallow to moderate depths in coastal and estuarine waters

Leopard seals: Highly opportunistic apex predators with a broad diet including krill, fish, squid, cephalopods, seabirds (especially penguins), and even other pinnipeds (e.g., seal pups)

They are known for aggressive hunting tactics, like thrashing penguins to “deglove” them for blubber. Some individuals specialize (e.g., penguin focused or krill focused)

Leopard seals sit much higher in the food chain and are one of the few seals that regularly prey on other marine mammals; their only natural predator is the orca

Behavior and Social Structure

Harbor seals: Often haul out in small to moderate groups but are not highly social

They are relatively quiet (growls, whistles) and can be wary but tolerant of humans in some areas

Pups are born on land/rock and swim soon after

Leopard seals: Mostly solitary (non gregarious). They are more vocal and known for their loud, haunting calls

Females are larger and give birth on ice

They are powerful, fast swimmers and can be quite bold or aggressive

Lifespan and Conservation

Both species can live 25–30 years

These Silly Sunday Seals aaaaalmost became Monday Seals but here we are :3

Reffed pics under the cut!