PICTURE A fisherman returning to shore somewhere in the Caribbean. Alongside his catch, tangled in his net, are plastic bottles, food wrappers, and a lone flip-flop that clearly didn’t come from anyone swimming nearby. “It didn’t used to be like this,” he grumbles. “Some days I spend more time pulling out garbage than fish!” For many coastal communities, scenes like this are becoming increasingly familiar. The sea that feeds families, supports t…