what relation does it have with humans?
They were used as food, and their feathers were used for decorative purposes and were also worn by the important members of the Māori tribe.
Australasian gannet
The Māori were reported to have harvested young gannets for food, visiting Gannet Island in March. The white feathers of adult gannets were used to adorn canoes, and were worn by important members of the community. The bones were made into tools to apply facial moko (tattoos).
what is a australasian gannet? A large seabird. where is it found? Steep Point in Western Australia, along the southern and eastern Australian coastline to the vicinity of Rockhampton in Queensland, as well as the North and South Islands of New Zealand, Lord Howe and Norfolk Islands. what does it eat? Forage fish and cephalopods. apart from this bird what are the other predators of the first one? Other fishes like tuna, striped bass, cod, salmon, barracuda and swordfish, as well as sharks, whales, dolphins, porpoises, seals, sea lions, and seabirds. where are they found? They are found along coastlines and also in lakes and rivers. does the original bird have a unique call? A  harsh "arrah-arrah" or "urrah-urrah". who are its predators? Southern giant petrel , kelp gull, and Pacific gull. how does the first one mate? It sexual maturity at six or seven years of age and the breeding season begins in October. what does it eat? Fish, krill, squid, offal , and waste from vessels. what is the sub-species of the second bird you mentioned? "L. d. dominicanus" and  "L. d. vetula" . can you please describe the third bird that you mentioned? A very large white gull with dark wings and back, and a very thick red-tipped yellow bill. what efforts are being made to conserve the original bird? It is a species of least concern, as the population is large and appears to be growing.
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Australasian gannet [SEP] Relationship with humans
The Māori were reported to have harvested young gannets for food, visiting Gannet Island in March. The white feathers of adult gannets were used to adorn canoes, and were worn by important members of the community. The bones were made into tools to apply facial moko (tattoos). Some mainland colonies have become tourist attractions, such as those at Cape Kidnappers, and Muriwai in New Zealand, and Point Danger in Australia. The gannets of Cape Kidnappers have featured on New Zealand stamps issued in 1958 and 2009.