New Zealand's two heavily endangered dolphin species could be saved from extinction if fishing restrictions were extended out to a depth of 100 meters around the coast, according to a New Zealand study.Protected areas, where gill nets and trawling were banned, had been shown to effectively stop the fall in populations of Hector's dolphins, which are believed to number just over 7,000, University of Otogo zoology associate professor Liz Slooten said.In the sanctuary at the South Island's Banks Peninsula, survival rates had risen by 5.4 percent since it was created in 1988, Slooten said in a statement Monday."However, nationwide, Hector's dolphins continue to slide towards extinction, mainly due to continuing by-catch in areas with few or no dolphin protection measures," she said.Hector's dolphins ranged to six nautical miles off the west coast of the South Island, but protection only extended to two nautical miles offshore, and then only for three months of the year, she said.Several scientific organizations, including the Scientific Committee of the International Whaling Commission and the International Union for Conservation of Nature (IUCN) had recommended that protection be extended out to 100 meters deep.If the recommendation were adopted, it was calculated that dolphin populations could recover to around 15,000 within 40 years.The New Zealand government has come under increasing international pressure to do more to protect its native South Island Hector's dolphins, which is believed to number just 7,270, and the North Island Hector's dolphin, also known as Maui's dolphin, which is thought to number just 55