like the corny humour here, and the bag works well as it bridges the duo and the sign together. it also adds a bochup feeling of nonchalance to the scene. personally i'd prefer it to be in b/w becos its quite contrasty n colours of the scene are not great.
Try and explore different angles of shooting. It's abomination in some individual's book to shoot the back of the people in candid-shots like these. Move to focus more of what they're doing, making the guy fishing the main subject of interest, rather than the notice of "no fishing". Doing the inverse, as you did so, just doesn't interest anybody.
I'd say it's a very typical Singaporean scene - people openly flouting regulations with excessive penalties that are never enforced. I think the scene is too common to make this more than a documentary picture.
I think the image could benefit from better contrast control (blown out sky and water) and tighter framing. The fishermen are pretty small, while there is a lot of background that doesn't seem to contribute much to the picture.