when I have come across dead seals they tend to be very smelly and have so much fat on them. I imagine composting a dead whale would be really smelly! I also know with seaweed it can be good to rinse some salt off first. lots of invasive plants like to grow on beaches around here. I think finding out which plants are not supposed to be there and composting those might be a good idea.
For anything that might be as smelly as a fatty mammal, it might be best to bury it near trees and let the roots deal with over the years.
I once spent the weekend on a small island where a whale had washed up a year earlier. The ribs and other things were already being used as garden fence posts and whatnot, but the layer of blubber was lying on the stoney beach like a big mattress, laying a greasy streak on the water out to sea, and giving off a powerful smell for a great distance around.
Works at a residential alternative high school in the Himalayas SECMOL.org . "Back home" is Cape Cod, E Coast USA.
I grew up about 800 miles up the Yukon River from the sea. We'd gill net king salmon for our food supply. The head and offal from three or four big kings would fill a galvanized wash tub, which my mother would have her children drag to the garden and bury in the paths between the rows of potatoes. It stank, but not as badly as the 55-gallon drum of "salmon tea" she'd make by filling the barrel with fish guts and then topping up with water. After working for a few weeks that got heavily diluted and used in her greenhouse on the tomatoes and peppers and cucumbers throughout their most productive month (August).
This was by far the richest source of fertilizer that went into our garden, excepting possibly the manure from dog teams that I would get paid to take care of in the summer time when their owners wanted to leave town.
Not me, my mother; I was like a pre-teen. But, yes. I know it's commonly considered a bad idea but we never had any problems with it. Typically she worked it into the soil in the fall after harvest, or in the spring a few weeks before planting. She also put a lot of it into her hot compost pile. It's my opinion that the common concerns about using dog poop are mostly unfounded, if you're smart about it
I never rinse seaweed in my high rainfall climate.
From what I understand, most sea salts are very valuable soil nutrients
and sea water contains pretty low levels of sodium chloride (aka the salt you don't want in the garden)
I would use basically any sea stuff I could drag home
I know people over here who burn anything 'shell' after eating the insides,
and add the high-calcium ash/char to the garden.
Think mollusks, bivalves, crustaceans, sea eggs...
The main thing I'm wary about is the potential smell-
if the system's not set up right, you can create a mighty stench, and I live in suburbia.
You get some magnesium sulfate, potassium and calcium from sea salt, but the bulk of it is SODIUM CHLORIDE. In my climate and in Leila's, salts are not a problem in garden additives, since many are salt deficient. Any salt that I add, will find its way back to the sea in short order. My late friend Ted, used to water several things with salt water. He wanted the magnesium, potassium, iodine etc. His home is 200 ft from the ocean and on gravel subsoil. Many plants thrive along the shore, where winter storms splatter them with salt.
This same addition of salt could be disastrous for many dry, inland soils, particularly those underlain with clay or hardpan. Proximity to the ocean does not guarantee that you should add salt. Dry coastal areas often have high salt levels in their soil. Spray from storms and unrinsed seaweed, can make matters worse.
just had another thought.....what about making hugel beds out of dead sea critters.......for example piling up seaweed, starfish, crushed clam shells, crab shells, fish heads and then covering the whole thing in some composted manure then planting some fruit trees/bushes on top.....after a while I think the hugel bed would start to shrink but the trees would have an abundance of nutrients for years.
Sean, you've described an incredibly rich mix. If you've got lots of shells, then you have calcium to counter the acidity of wood waste. Fish guts and seaweed are very high in nutrients. Wood is low, but makes a great sponge to absorb and hold those nutrients. A mix like you describe, would stink. Whenever there's a repugnant, rotten fish smell, nitrogen is being lost to the air. Wood is abundant. Use it and improve it with everything you mentioned.