A few Imperial fleets avoid Zemeh and trade with a few of the scattered states to the south of the Republic - adding several weeks to their journey. These smaller states tend to either look to Sumaah for protection, or else are hostile to foreigners of every stripe - in either case they trade in roughly the same goods (OOC: It is fine to role-play trading with one of the subject nations, but your character will receive the same goods regardless of whether they go to Nemoria proper or not.)
Imperial traders visiting Zemeh are often drawn by the opportunity to purchase liao - it is one of very few places outside the Empire that creates this rare visionary narcotic. Indeed, Sumaah law carefully regulates the sale of liao to non-Imperial traders, considering it a crime verging on blasphemy to sell the substance to those who might use it for irreligious purposes.
While foreign visitors are made welcome, they often report a feeling of being watched and their behaviour judged. It is possible that the hot, humid climate is at least partially responsible for the discomfort felt by visitors - Zemeh is on the coast, but the jungles press close to the walls and merchants used to more temperate climes often find it oppressive. Foreigners are not welcome outside the walls of Zemeh - those discovered in the jungle are usually ejected and asked not to return but more serious trespass may result in much more draconian punishment.
It should be noted that the Sumaah Republic is not a police-state, however. The people are often genuinely hospitable, and reasonably tolerant of the idiosyncrasies of outsiders - with the exception of Asaveans, who are not welcome here.
In addition to Liao, the Sumaah are particularly rich in dragonbone which is particularly abundant in the jungles of the interior; their mines provide them with a surplus of orichalcum; and the herb that Imperials know as Imperial Roseweald grows especially abundantly in this warm country.
Trade with Zemeh
A starting fleet resource that engages in trade with Zemeh during downtime will produce 4 ingots of orichalcum, 4 measures of dragonbone and 3 vials of liao. A fleet that has been upgraded will produce more valuable resources according to this chart of foreign ports (including imperial roseweald).
Gateway to Timoj
Since the Winter Solstie 382YE, a white granite highway connects the port of Zemeh with the Sumaah capital city of Timoj. A steady stream of pilgrims from across the known world heads south into the heart of the Republic.