科学 · ダーウェント川のマンボウ巨大なマンボウが深い水域へ押し出された。その後、戻ってきた。執筆 2026年11月6日 2:42 UTC視聴文字起こし0:07A sunfish returned to the shallows after a resident pushed it toward deeper water.0:12Marine biologist Neville Barrett said the animal would probably die, with freshwater0:17exposure adding to his concern.0:19How did an ocean-going fish reach so far upriver, and what chance did it have of0:24surviving?0:25Chris Reed found the fish near the Gasp Walkway at Montrose Bay in Hobart's0:30northern suburbs.0:32He was walking with his children, nose and sven, when they spotted the animal lying0:36on its side in shallow water.0:38At first, they thought they were looking at a seal.0:41A woman nearby thought it was an injured shark, and Reed briefly wondered whether it0:46was a young whale.0:47He'd never seen a sunfish before.0:49He sent a video to his friend Elliot Stiles, who identified it.0:54Reed estimated the sunfish was over two meters long, and just as high those0:58dimensions came from what he saw in the water.1:01Even without a measurement, his description gives a sense of the animal he tried to1:05move.1:06Reed entered the water and pushed the fish outward until he was a little more than1:10waist deep.1:11He stopped as the bottom became too rocky, with shells underfoot, and he was getting1:17cold.1:17Someone on shore told him a call had been made, and assistance was coming.1:22By around three p.m., when Reed returned, the fish had moved all the way back into1:27shallow water.1:28He wondered whether it was confused or injured.1:31His effort to push it farther out hadn't kept it away from the shallows.1:35Sunfish rarely enter an estuary like the Derwent.1:39Barrett, a research associate at the Institute for Marine and Antarctic Studies,1:44described this sighting as extremely unusual.1:47These animals live mainly in the open ocean, and they're rarely seen even in coastal1:53waters.1:53Sunfish inhabit both tropical and temperate oceans, including waters as far south as1:59Tasmania.2:00Barrett suggested that the shape of the Derwent could help explain how one might end2:04up so far inland.2:05The Derwent narrows inward from Storm Bay.2:08Barrett suggested that this shape could funnel an ocean-going fish farther upstream,2:13leaving it struggling to find its way out.2:15That's one possible explanation for its arrival at Montrose.2:19There have been earlier Derwent sightings.2:21Two separate red map records name Richard Curtis and Theo Muir Wilson in2:26December2014 .2:28Barrett also described occasional sunfish encounters around Norfolk Bay, and a2:34recent animal washed up near Bernie.2:36Barrett put an average sunfish at roughly two hundred fifty kilograms to one tonne.2:42He said they can reach two and a half tons or more.2:45Those are general figures.2:46This fish wasn't weighed, but that bulk helps explain why moving one is so2:51cumbersome.2:51Barrett's concern went beyond the animal size.2:54He thought its return to the shallows suggested it was already in poor condition.2:59River runoff also brings fresh water to the surface in this part of the Derwent.3:04A fully marine fish isn't adapted to live in that environment.3:08Barrett believed the fish would probably die because of its apparent condition and3:12exposure to freshwater-influenced water.3:15Nobody has confirmed what happened afterward, including whether help arrived,3:20whether it reached open water, or whether it died.3:23Unusual sightings also contribute to Redmap, the marine observation project3:28associated with IMAS.3:30It collects community observations of species uncommon in a particular area.3:35Researchers use those records to log and map sightings and help track changes in3:41where marine species occur over time.記事を読むストーリーの時系列HeyDex
