In southern Kyushu, you hear people speak of a biting bug called チックン that lurks in shallow water near beaches. Researching the word a bit comes up with the more standard term チングイ, and it appears to be some kind of larval-stage arthropod. Whatever its biology, it's painful to be bitten by one. Are these terms equivalent, the one simply Kyushu-ben? Is anyone aware of any other variants? And can anyone provide a scientifically meaningful translation of the name? The best I've found so far is 'zoea', which is very vague.
I live in Kyushu. Maybe you are referring to チンクイ (not チングイ), also known as チンクイムシ. This is the common name given to the larval stage of crustaceans. Utterance of which could incite giggles from the ladies. The proper name in Japanese is ゾエア, from the English name that you mentioned. (Reference: https://kotobank.jp/word/%E3%83%81%E3%83%B3%E9%A3%9F%E3%81%84%E8%99%AB-1465715)