They capitalized on the natural resources by using the salt to cure fish, which they exported to their home country.
( They ( ( ( capitalized ( on ( the ( natural resources ) ) ) ) ( by ( using ( the ( salt ( to ( cure ( ( fish , ) ( which ( they ( exported ( to ( their ( home country ) ) ) ) ) ) ) ) ) ) ) ) ) ) . ) )
(ROOT (S (NP (PRP They)) (VP (VBD capitalized) (PP (IN on) (NP (DT the) (JJ natural) (NNS resources))) (PP (IN by) (S (VP (VBG using) (NP (DT the) (NN salt) (S (VP (TO to) (VP (VB cure) (NP (NP (NN fish)) (, ,) (SBAR (WHNP (WDT which)) (S (NP (PRP they)) (VP (VBD exported) (PP (TO to) (NP (PRP$ their) (NN home) (NN country))))))))))))))) (. .)))
They kept all of the salted fish for themselves. 
( They ( ( ( kept ( all ( of ( the ( salted fish ) ) ) ) ) ( for themselves ) ) . ) )
(ROOT (S (NP (PRP They)) (VP (VBD kept) (NP (NP (DT all)) (PP (IN of) (NP (DT the) (JJ salted) (NN fish)))) (PP (IN for) (NP (PRP themselves)))) (. .)))