In April, Belfast city councilors unanimously approved zoning ordinance changes that would allow a company planning one of the world’s largest indoor salmon farms to advance to the next stages of the project. In the months since, tensions have risen among midcoast Mainers over Nordic Aquafarms’ plans for the project, and earlier this summer, two Belfast residents filed a lawsuit alleging that the city did not follow its own process when it gave the greenlight to the zoning changes. More than 150 people squeezed into the Troy Howard Middle School cafeteria Wednesday night to share their thoughts before the Belfast Planning Board during a public hearing on the issue.