this is "nightline." tonight, sea of shadows. the illegal hunt for a prize black market fish triggering a dangerous war in the waters off mexico. >> we call it the cocaine of the sea. >> and caught up in the nets, a rare por pous. >> we can't give it on the planet. >> inside the desperate race to save it from extinction. >> plus the new princess under the sea. support and criticism over how beloved fictional mermaids should look. hallie bailey of r&b chosen to play the iconic role of aierial. inside the reboot of the disney classic as a debate heating up

across social media. and heros welcome for the national women's soccer team rolling out the red carpet for the world cup champs as they get the party started here in the usa. but first the "nightline" five. monitor their blood glucose every day. which means they have to stop. and stick their fingers. repeatedly. today, life-changing technology from abbott

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thanks for joining us. tonight a fierce appetite for a treasured fish delicacy in china. now a new national geographic film documents the illegal hunt and the race to save a rare porpoise caught up in the nets. >> more and more poachers are coming. >> reporter: in the sea of cortez off the coast of mexico. >> they're continuing to throw things. >> reporter: there is a war in the waters. not over drugs. >> it's alive. >> reporter: but over illegal fishing. the prize? the large fish only found in these waters and treasured on chi china's black market for its swim bladder. cooked in soups to satisfy chinese consumers who believe the organs have medical properties.

>> they call it the cocaine of the sea. it's worth more than gold. >> reporter: now the bass is endangered. they've been dangerously overfished and human activity has reduced their natural habitat. >> we filmed like this at $100,000 a piece. >> reporter: a mine field under the surface taking the lives of scores of other marine life. >> these nets are anchored to the sea floor, and so they can't pull the nets up to the surface to take a breath. and so a marine mammal or sea turtle, they're going to drown quickly. >> reporter: the nets also lethal for a rare porpoise that's the smallest marine mammal in the world. driven to the brink of extinction with less than 15 left globally. >> i keep thinking about only one being left in the wild. this is a war against the extinction of a species. >> reporter: it's one of the million species the u.n. recently identified as facing

extinction. the rarest marine mammal caught in a web of illegal fishing. mexican cartels and the chinese mafia. >> it's highly symbolic. it's like what we are doing to the sea of cortez and this animal is -- it's a case study of what we're doing to the planet. >> reporter: this is an alarm bell ringing and i hope everybody really sits up and pays attention. >> the clock is ticking. >> we will fight for every single life. >> reporter: all this now the subject of a new national geographic documentary sea of shadows. >> you talk about in the film you imagine the animal calling out for help and nobody hearing that call. >> yeah. it was actually a dream. i dreamed the last one on earth calling out to others, to family members, but silent. and that haunted me. >> to let an entire ocean die because of the greed of a few

and be okay with that? that is unacceptable. as a species, that is unacceptable. if that happens, we should be ashamed. >> reporter: thetags together t the very groups working to rescue this animal. why this topic? why mexico? why this porpoise? >> i did this other called the ivory game about elephants. one person has in his hands the destiny of an entire species. it was a successful film. at the end china banned the ivory trade. i heard about this porpoise crisis from one of the characters of the film. we saw with our own eyes, they escaped. back here like a safe haven for the poachers. it smells. the whole thing stinks. >> reporter: andrea is a hard charging conservationist with a background in security. his team consisting of former fbi and intelligence officers

aims to choke off the chain of criminal activities driving this crisis to the brink. >> from the outside it looks like any environmental story. when you dive, you understand the role of transnational crime. working with chinese traffickers where they form what we call cartels because they work in the same way. with the incredible power to corrupt all over the places. >> i got the call to join a group of veterinarians and scientists who help save this porpoise from extinction by bringing it into human care. no other option was working. >> reporter: while one team works on land on the criminal side, cynthia smith leads a team of scientists trying to rehabilitate. >> there were 100 and then 60 and 30. and now there's fewer than 30. >> the dilemma was if we brought an animal into our care and it was showing us clear evidence

that it wasn't acclimating to humans, that's when the difficulty comes in. there's 15 left. there's so few of them left to release them back knowing the nets are there, and they may drown tomorrow. >> reporter: it's a dilemma they faced head on when after weeks of trying they finally spot the elusive vakita. >> i remember the call. we have two out three miles north of the buoy. everyone was racing there. they're like okay, this is it. >> it's like a lightning bolt. it goes across the water and everybody just feels the energy and the excitement, but also the tension. and the nerves. >> suddenly it was there. it was real. it was in front of us. no ghosts. really there. my god, we all fell in love with it. it was an amazing experience to be so close to an animal that never had ever been close to. nobody had ever touched alive. >> reporter: despite their efforts, the vakita couldn't

acclimate. it died after a few hours. >> it's hard to talk about. i thought why is it different? i think it's because the night that we lost that animal, it just felt like the whole species was slipping away from us. and to have her slipping through our fingers like that and not be able to just, you know, hold onto her. it was hard. >> reporter: are you okay? >> let me take a minute. sorry. yeah. it's amazing how raw it still is. >> reporter: yeah. >> i think it is still so raw because we're getting that much closer to losing the species. >> reporter: the fragility of the species. the danger is real and the stakes couldn't be higher. >> all right.

>> reporter: the film team joining the crew aboard sea shepard known for full throttle tactics to protect the environment. >> they have three ships there. they're young, super motivated people who go out there and stand up to the cartel on the front lines and that is very dangerous. >> reporter: it's the high season. >> that's why all the illegal fisherman are going out at sea and traffic is intense. >> reporter: what do you want viewers to take away from this? what is their responsibility after seeing sea of shadows? >> it's a very urgent matter. i would say we have six, eight

months to save the vakita. we need to stop the illegals from going out in december. if they go out again, it will most likely be the oend of it. >> we cannot give up. we can't give up on the sea of cortez or the planet. >> reporter: for "nightline," gloria riviera in washington d.c. >> sea of shadows opens in theaterss thursday. up next the historic casting of the little mermaid sending shock waves across land and sea. oh! oh! oh! ♪ ozempic®! ♪ (announcer) people with type 2 diabetes are excited about the potential of once-weekly ozempic®. in a study with ozempic®, a majority of adults lowered their blood sugar and reached an a1c of less than seven and maintained it. oh! under seven? and you may lose weight. in the same one-year study, adults lost on average up to 12 pounds.

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singer halle bailey is making a splash chosen to be the newest disney princess in the reboot of "the little mermaid". a dream come true for her while others are criticizing her for the role. ♪ these old days i don't feel that much ♪ >> just listen to that voice. isn't it neat? ♪ darling when you smile it's like the rain plays out ♪ . >> the selection is complete. disney has a new princess and her name is halle bailey. the actress cast to play ♪ wish i could be part of that

world ♪ >> reporter: as some praise the bold move, others criticizing the pick online questioning whether a black woman could portray the redheaded princess. the skin color front and center. some tweeting this isn't about racism. we just want a princess that looks like the one we love and stop ruining the classics. >> i think most of the pushback has come from those dark pockets of social media where people want to be antagonistic or want to see people arguing or to just take away from this beautiful moment. but overwhelmingly, people are excited. >> reporter: celebrities like mariah carey coming to her defense joining the outpouring of support on social media. disney the parent company of abc news also owns free form tweeting a tongue and cheek letter reminding people the

character of ariel is a work of fiction. for 30 years the little mermaid has enchanted audiences with songs like poor unfortunate souls. ♪ pathetic poor unfortunate souls in pain in need ♪ >> reporter: and under the sea. part of a generation's collective memory. >> the little mermaid was a movie that was made when we were kids. it was made for us. >> listen to me. the human world, it's a mess. >> reporter: when the original was released in 1989, it was a megahit, becoming the first animated film to gross more than $100 million at the box office. and ushering disney's renaissance era. ♪ but i'm a little bit dumb just a little too late ♪ >> reporter: and halle bailey is now ushering in a new chapter for the iconic story. she's one of the sisters in cloey and halle who has hit

songs like happy without me launched them to stardom. the 19-year-old sharing her excitement with her 2 million instagram followers. posting this with dream come true caption. ♪ someday i'll be part of your world ♪ >> reporter: that illustration allowing fans to envision the next little mermaid. the artist behind it, dylan bonner. >> the fact that kids now are getting to see themselves in it or see fairy dust in a part of their life they didn't get to see before and being tied to my image, that's exciting. the illustration i did in 2015. >> reporter: he drew the artwork after it was -- >> her boyfriend wanted her to see herself the way he saw her in that special disney light. >> reporter: never expecting that the message behind the gift would be shared around the world. >> i think she's really excited now that it's sort of taken on

this whole meaning that's way bigger than me or her or the initial project. because now i feel no ownership to that picture, because it belongs to everyone else now. >> reporter: the siblings who i sat down with in 2016 started on youtube covering pop songs and eventually getting the attention of none other than beyonce. >> you all became, youtube sensations. right? how did that come about? >> we just started doing youtube covers. we were like we're kind of bored. let's do this. let's sing this song that we like. ♪ turned out to be the best thing i never had ♪ . >> it continued to grow and we were like oh, wow. people like this. >> reporter: it wasn't long before beyonce herself was calling. how did she hear about you? >> we did the cover to "pretty hurts". ♪ pretty hurts >> out of all the covers it got the most traction and two weeks later we got the call from park

wood. >> reporter: they got a deal and the rest is history. what do you think of beyonce? >> she's a great road model. >> reporter: best advice? >> believe in yourself. it sounds cliche. you've they've toured with her and also got roles on tv. even singing the intro song. ♪ >> reporter: the little mermaid will be bailey's first feature film. >> well, look at what the cat fish dragged in. >> reporter: the casting representative of so much more than one woman's assent to stardom. >> when they announced that halle was playing, i wasn't prepared for that. i did not expect that.

>> i was to proud of her that i even talked about it in my sleep. >> so you'd like to be a mermaid someday? >> yeah. >> reporter: this daughter is six and is excited to see someone who looks like her daughter in the iconic role. you know, ariel and the little mermaid are important because that was the first big disney hit in decades when it came out. and two, ariel saves the prince. she's the first feminist leaning disney princess. it changed the representation of the girls in those movies. when i think about seeing a little brown girl with long dread locks playing ariel someone with hair that looks a lot like what my daughter is rocking right now, putting on the tail and singing the songs, that to me is black girl magic. >> when i hear the phrase black

girl magic, i feel like myself. i feel like that's me. that's me and my mom. that's us. >> reporter: we keep hearing this phrase, black girl magic. what does it mean to you? >> don't be afraid. you're magical. you hold so much power in your hands. ♪ watch and you'll see >> reporter: now that magic coming to the big screen. for "nightline," i'm buyron pits in new york. up next the victorious homecoming for the world cup champions. you gauge the greatness of an suv? is it to carry cargo or to carry on a legacy? its show of strength or its sign of intelligence? in crossing harsh terrain or breaking new ground? this is the time to get an exceptional offer on the mercedes of your midsummer dreams at the mercedes-benz summer event, going on now. lease the gla 250 suv for just $329 a month

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and finally, a heros' welcome. it's a royal homecoming. the u.s. women's national soccer team back home after scoring their fourth world cup title in france. wednesday new york city will throw a ticker tape parade and the women eyeing their next battle to even the playing field with the men's soccer team by fighting for equal pay. and a huge congratulations to all. be sure to tune in to gma for a live studio interview with all

the players and we'll have more on "nightline" tomorrow. you can catch our full episodes on hulu. good night, america.

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