Hong Kong’s century as a British territory gave it connections to merchants in the former African colonies who traded in elephant ivory, rhinoceros horn and animal skins prized by consumers around the world. The city was the center of the international ivory trade until it was banned in 1989, importing as much as 700 tons of tusks from Africa annually at its 1970s peak.

For years, Hong Kong has been a leading importer and exporter of shark fins — a popular soup ingredient in Cantonese cuisine. By the most recent available statistics, the territory leads the world in imports of live fish and reptiles.

Much of this legal trade is visible in neighborhoods like the commercial district of Sheung Wan, where storefronts crammed with dried sea horses and birds’ nests crowd the street beneath billboards of the Kardashians.

Conservationists charge that this legal commerce complicates efforts to tackle Hong Kong’s role as a key node in the global illegal trade. Once they are skinned and dried for sale, the fins of the endangered scalloped hammerhead shark, for instance, are almost impossible to distinguish from the fins of legally caught blue sharks in Hong Kong’s seafood shops.

Among the dried fish swim bladders — also a popular soup ingredient — hanging in the same shop windows, it is similarly difficult to distinguish the sustainably caught species from the swim bladders of the totoaba, a critically endangered fish whose illegal harvest off the Pacific Coast of Mexico has also pushed the vaquita, a porpoise that is often caught in fishing nets, to the edge of extinction.

The massive growth of the shipping industry and global connectivity have made the markets for these species ruthlessly efficient and fast-moving. “I’m wondering, what’s the next species?” said Timothy C. Bonebrake, a biologist at the University of Hong Kong’s conservation forensics laboratory, which assists local law enforcement in analyzing wildlife contraband.

“Is there a way you can be proactive about this and stop it before these things are all critically endangered? And certainly, in Hong Kong, we’re seeing there is always a new species, all the time.”