This was a large and long duiker 4m x 135m but without having to drain the duiker I could easily take lobster pots into the duikers and catch them. Once caught I'm sure you could sell them to local businesses with any proceeds going to good causes.
BTW, I was also asked to find Muskratten habitats. I was brought to an area where they were known and I was able to find one with the sonar. I was also able to enter it with the ROV so it was at least 600mm in dia. . Due to the sediment I wasn't able to see much but on the sonar I was able to follow the path up to where it forked about 7m inside.