marine biologist volker koch from the german development agency giz is helping the local national park service establish new conservation areas. >> it's often complicated because the general public often thinks that they can't do anything in these areas any more. it can take a while to explain to them that what's been happening so far is unsustainable but that they can follow the example of the people here in cabo pulmo, for example. ecotourism makes the most of the local biodiversity much more than fishing does. >> the gulf of california is a biologically rich region. the largest animals in the world, blue whales, spend the winters further north in loreto bay. they breed and calve in the temperate zones off baja california before heading off to the arctic.national park. fishing is heavily restricted and only permitted in specific zones. in winter, fisherman martin castro packs away his nets and takes tourists out on his boat to go whale spotting. sometimes, they'll also get to see dolphins. sea lions are also a popular tourist attraction. in recent years, tourism has become a major so