A newborn calf spotted among a population of critically endangered killer whales has a good chance of surviving into maturity, scientists say. Researchers are hoping that the juvenile whale - which has been given a 50 per cent chance of living into adulthood, is a female. This will give the group the best chance of producing more offspring, they say. The calf, known as L124, is part of a group of orcas known as the Southern Residents whose population has been shrinking for decades and currently numbers at 75. Footage captured in recent weeks revealed several groups of killer whales in Puget Sound, near Seattle, including the calf. Around 50 per cent of newborn calves do not survive their first few years and no calves born to the group since 2015 have grown to maturity. A severely depleted food source due to salmon fishing off the West Coast of the US is behind the decline, as well as pollution and noise from motorboats, scientists say.https://www.youtube.com/embed/GM0XCD4KNak?feature=oembed A newborn calf spotted among a population of critically endangered killer whales will survive into maturity, scientists say. Researchers are hoping that the juvenile whale is a female, as this will give the group the best chance of producing more offspring (file photo) Currently, two other orcas in the group are known to be sick, and researchers feat they could die within months and not survive until summer. But scientists are nevertheless optimistic about the calf's survival into maturity and have described it as looking 'healthy' so far. 'I wish I could say that the odds are good, but unfortunately, the Southern Residents aren't doing too well right now,' , Melisa Pinnow, a biologist with the Center for Whale Research in Washington State, told the New York Times. 'In the last three years, every calf that's been born has died and we've had miscarriages as well.' The sex of the calf has not yet been confirmed but scientists are hoping that it's female. David Ellifrit, a biologist on the boating trip to get close the whales, said: 'Hopefully it's a female, because we need more reproductive-age females.' In the 1990s there were nearly 100 orcas in the group and this number has now reduced to 75. The low number also increase the risk of inbreeding, which could further hurt their long-term survival. Nevertheless, another addition to the female population would be a boost to reproductive chances and the of survival for the group as a whole. The new calf's mother is 31-year old mother and has given birth to two calfs in total. Her first was born in 2010 but died the same year, and her second was a female born in 2012 that managed to survive. The calf, known as L124, is part of a group of orcas known as the Southern Residents whose population has been shrinking for decades and currently numbers at 75. Footage captured in recent weeks revealed several groups of killer whales in Puget Sound, near Seattle (pictured) In this Jan. 18, 2014, file photo, an endangered female orca leaps from the water while breaching in Puget Sound west of Seattle as seen from a federal research vessel that has been tracking the whales. Two conservation groups say the federal government is violating the Endangered Species Act by failing to consider how salmon fishing off the West Coast is affecting endangered killer whales. (AP Photo/Elaine Thompson, File) The main issue for their survival is the depletion of their main food source, the Chinook salmon. The southern resident population of orcas differ from some of the other orca populations in eating primarily salmon, rather than seals or other marine mammals. Last summer, the tragic images of a mother Orca carrying her dead calf on her head for 17 days made international news. Other environmental factors that are contributing to the species decline include sea pollution and loud noise from boat traffic. WHAT ARE TYPE D KILLER WHALES? These majestic creatures - which were only identified in 1955 - have only been spotted a handful of times in the past 70 years. When they were first discovered after a mass stranding in New Zealand in the 1950s they were thought to be a mutated type of the worldwide orca species. They are so distinct from other orcas some experts believe they should even qualify as their own species. Compared to normal dolphins, these orcas have more bulbous heads and sharper dorstal fins. These majestic creatures - which were only identified in 1955 - have only been spotted a handful of times in the past 70 years The patches over their eyes are smaller than on other species - A, B and C - which are all known to dwell in Antarctic waters. They are especially distinctive due to their small eye patches. They have been seen eating Patagonian toothfish but it is unknown if they exclusively eat fish. Experts believe that if they are a new species they could be the largest undescribed animal left on the planet. The orcas were listed as endangered under the Endangered Species Act in 2005. The following year, the fisheries service designated the inland waters of Washington state as critical habitat. The designation means federal agencies must ensure that activities they pay for, permit or carry out do not harm the habitat. Last month Washington Govnor Jay Inslee announced a $1.1 billion to help the species recover in number as well as a partial whale-watching ban. All rights reserved for this news site dailymail and under his responsibility