shellfish, poaching temp. and factors

[shahar]

What would be the best temp-time ratio for shellfish. Mainly lobster, shrimp, calamari? Low-long, high-short, other?
Also what's the effect, if any, of additivies to the poaching liquid? Namely salt, suger, acididy/acridness?

[Harold McGee]

Most shellfish are best cooked quickly at a high temperature. Like fish, they have very active protein-digesting enzymes in their tissues, and at low temperatures they can digest themselves into mush. Squid and octopus are something of an exception—their flesh is rich in connective-tissue collagen, and long cooking will dissolve it into gelatin and make them more succulent. Moderate levels of salt and acid won’t have much of an effect.

Harold