Progress to date and what to expect when the fourth session of the Intergovernmental Negotiating Committee – INC-4 for short – opens in Canada later this month.

With only an estimated 10 individuals left, the vaquita porpoise is the world’s most endangered marine mammal, pushed to the edge of extinction by illegal fishing for the dried swim bladders of totoaba fish which are in high demand in Asia. But despite the species’ alarmingly low numbers, recent...