Simplify the following text for a Grade 9 native English-speaking person.
Original: Also at age nine he wrestled his first crocodile , again under his father 's supervision . He worked as a volunteer for Queensland 's East Coast Crocodile Management program and captured over 100 crocodiles , some of which were relocated , while others were housed at the family park .
Simplified: He also worked for free for the Queensland Government 's East Coast Crocodile Management program .