(S (S (S (S (NP (BASENP (NN Fifteen)) (PP (IN of) (BASENP (PRP them)))) (VP (VBD died))) (COMMA ,) (SBAR (IN although) (S (BASENP (DT the) (JJ other) (NN 33)) (VP (VBD were) (VP (VBN re-floated) (ADVP (RB out) (PP (TO to) (BASENP (NN sea))))))))) (COMMA ,) (PP (VBG according) (PP (TO to) (BASENP (DT a) (NN conservation) (NN official))))) (PERIOD .))