Orange roughy (Hoplostethus atlanticus) is a deep ocean fish that grows and matures at a sluggish rate compared to most shallow water fish. They don't reproduce until they are at least 20 years old and can reportedly live to well past 100 years.
In the last few decades fisherman have expanded their fishing territory into deeper waters, including the roughy's habitat. Heavy fishing coupled with the fish's slow reproductive cycle put this fishery in serious decline.
Heavy orange roughy fishing has taken its toll in other ways, too. The wide mouth of the trawl net often pulls in other unwanted animals, called bycatch, which are usually thrown back into the ocean dead or dying. Areas of the seafloor and seamounts where roughy hang out have also been scraped and scarred by trawl nets and can take decades to heal.