william carswell is a sea otter biologist with the u.s. fish and wildlife service. >> these habitats provide food for hundreds upon hundreds of species. >> reporter: the otters have established themselves off the san mateo coast. human assistance could potentially connect the southern and northern populations in the pacific northwest. >> san francisco is an anomaly. it would be a huge prize and yet it is also a huge risk as well. >> reporter: those impacts are weighing heavily on fishermen who have seen a local marketplace decimated by growing restrictions to address whale entanglements since 2016. ogg has been helping state and federal regulators come up with solutions but a reintroduction of a subspecies in the bay is where he draws the line. >> my main concern has been the moral issue regarding whether it is right to do and whether it is something that is going to benefit the animal itself. >> reporter: it is a risk that the crabbing industry cannot take , and another potential disruption to the livelihood of crew members and so much mo

william carswell is a sea otter biologist with the u.s.h an wildlife service. >> sea otters tend to promote the growth of kelp and these habitats provide food for hundreds upon hundreds of species. >> reporter: the otters have established themselves off the san mateo coast. human assistance in the san francisco bay could potentially connect the southern and northern populations in the pacific northwest. >> san francisco would be a hug prize but a huge risk as well. >> reporter: these impacts are weighing on the fishermen, who are seeing the local marketplac being hit by restrictions. the have been helping state and federal regulators come up with solutions. the reintroduction o a subspecies in the bay is wher he draws the line. >> my concern is the moral issu regarding whether it is right t do and whether it is something that is going to benefit the animal itself. >> reporter: it is a risk that the crabbing industry cannot take, with another potential disruption to the livelihood of crew members and more. they believe that natural expansio