[ti:Alaska’s Salmon Becoming Smaller] [by:www.51voa.com] [00:00.00]更多听力请访问51VOA.COM [00:00.04]Alaska's salmon - popular among seafood lovers around the world - are getting smaller. [00:09.24]Their change in size might be a result of climate change [00:14.64]and increased competition, a recent study said. [00:20.32]The study, led by University of Alaska at Fairbanks (UAF) scientists, [00:28.84]found that four of Alaska's five wild salmon species [00:34.12]have shrunk in average size over the past sixty years. [00:39.96]Alaska's official state fish, the Chinook salmon [00:45.08]- also known as king salmon – have decreased the most in size. [00:51.16]Chinooks are 8 percent smaller, on average, than they were before 1990. [00:59.60]The study, which appeared recently in the journal Nature Communications, [01:05.60]also said Alaska's sockeye, coho and chum salmon are shrinking. [01:13.20]The findings are based on data from 12.5 million samples collected over six decades. [01:22.08]Peter Westley of UAF's College of Fisheries and Ocean Sciences co-wrote the study. [01:31.32]It confirms some stories told by Alaskans [01:35.16]who have lived in the state for many years, Westley said. [01:40.60]"People are walking into their smokehouses [01:43.64]and not having to duck anymore...The fish are just smaller." [01:49.04]A smokehouse is a building in which meat is cured with smoke. [01:54.64]The likeliest reasons for the fish shrinkage, Westley explained, [02:00.28]are warmer seas resulting from climate change [02:04.52]and increased competition among all species of salmon. [02:10.24]Salmon are maturing in the ocean at earlier ages, the study found. [02:16.48]The salmon return to fresh water at younger ages [02:21.12]and smaller sizes than they did in the past. [02:25.48]In some of Alaska's rivers, the really big fish that spend [02:30.60]seven or eight years in the ocean are no longer seen, Westley said. [02:36.68]Alaska produces nearly all of America's wild salmon. [02:42.00]Last year, fishermen harvested over 206 million salmon [02:47.80]and sold them for $657.6 million, state officials reported. [02:55.64]Salmon are also an important food for indigenous people of Alaska [03:02.28]and Canada's Yukon Territory. [03:05.60]The reddish fish are also eaten by Alaska's bears and other animals in the wild. [03:13.20]Smaller fish mean fewer salmon eggs - and fewer calories for those animals. [03:20.52]That could have long-term effects on the salmon population [03:24.72]and the animals that feed on them, said UAF's Krista Oke, the study's lead author. [03:32.08]The findings show the need to manage salmon not just for the size of their runs [03:38.68]but for the size of individual fish, Westley said. [03:43.60]"If you lose the diversity of fish and only have small fish, [03:48.88]then you're in troubled waters," he said. [03:52.60]I'm John Russell. 更多听力请访问51VOA.COM