The persisting labour shortage in the cacao, coffee and logging industries led to a booming trade in illegal canoe-based smuggling of Igbo and Ibibio workers from the Eastern Provinces of Nigeria. The number of clandestine contract workers on the island of Fernando Po grew to 20,000 in 1942. A labour treaty was signed with the British Crown in the same year. This led to a continuous stream of Nigerian workers going to Spanish Guinea. By 1968 at the time of independence, almost 100,000 ethnic Nigerians were living and working in Spanish Guinea.