[MENTION=4937]Celebrim[/MENTION] & MGibster I think you are right. I was hoping to create some detailed Aquatic tech levels but I can't think of a away to get them through the lower tech levels.
Yeah, it's not at all obvious how you go about it. The lack of fire probably isn't even the biggest problem. Equally big is how you go about separating something, or mixing it without contaminating/diluting it. Even without fire, humans use processes like dyeing, curing, and drying to alter the properties of natural materials - skins, plant fibers, etc. It's not clear how you go about doing that basic materials handling underwater. Forget bronze, how do you go about making raisins, beef jerky, salt, leather, baskets, pottery, thread, etc.? Once you have some basic materials science whether it comes out of the need for preserving food or providing shelter or whatever, then you can start building more and more elaborate things with the technology. But how do you do alter the normal chemistry of the thing when its bathed in a salt water bath filled with microbes the whole time. To me, getting actually well into the neolithic beyond perhaps simple stone smashing/scraping tools is actually the real challenge to my imagination.
One of the biggest challenges to imagining underwater technology, is given the problems of developing technology underwater, it seems like its easier and more likely to be successful to evolve a tool than create one. Hense you get amazing creatures like octopi and cuttlefish with an amazing variaty of adaptive abilities - color changing, shape changing, poisons, inks, jet propulsion, manipulative digits, biting mouths, etc. That's what tech 0 looks like in an aquatic species, but its not at all clear where it goes from there.
I imagine that some technologies that you have to create early on include:
1) Self-resealing containers.
2) Hypodermic needles.
3) Water proof linings.
I would imagine early aquatic technology is mucus based. The early technology hurdle to overcome is osmosis. You need to create membranes so that you can create a space with a different chemistry than the surrounding world. So you either need a base species that can create mucus with useful properties or else to domesticate some sort of mucus producing species. Spider silk is interesting, in that the Diving Bell Spider seems to be able to produce it underwater, so we have some sort of self-drying excretion that forms a strong water resistant substance. Early aquatic technology is probably similar in some ways to the diving bell spider's bubble based technology. Some sort of natural mastery of chemistry like that could form the basis of more sophisticated technologies.
So maybe you have a species that starts out weaving nets/membranes to protect itself from predators, and then starts weaving (non-sticky) nets or membranes that lets it contain some sort of edible/useful species until its dinner time while protecting it from predators. Eventually this leads to domestication. Perhaps the domesticated species is also a chemical producer, and its starts milking it for 'ink' or maybe the domesticated species is the original mucus producer and its entered into some sort of symbiotic partnership. In any event, eventually the species learns that it can contain chemicals in bubbles and that within these bubbles other materials undergo transformations. For example, maybe the start containing luminescent compounds in bubbles to make them portable, or maybe they figure out how to blend the precusor compounds in a bubble to create a temporary light - which lets them harvest food later into the evening. Anyway, its highly likely that the sort of things that they invent and the order in which they invent them would be nothing like land dwelling creatures. Almost all of it depends initially I think on leveraging existing biological materials.
