Day twenty-seven, 5:30 a.m.

The horizon was still a deep, inky blue, with only the eastern horizon painted by a faint grayish-blue light.

Inside the shelter, Lin Yu'an had already finished breakfast. Today's energy boost came from a few smoked cod fillets and a steaming hot mussel broth.

He carefully checked the equipment he was about to set out with. A bundle of approximately four kilograms of mixed charcoal, tied with nylon rope, was his only source of warmth on this journey. In his backpack were boiled mussel meat and fish jerky wrapped in birch bark, with his sleeping bag securely fastened to the bottom of the pack.

Stepping out of the shelter, he secured all his tools on a makeshift sled made from driftwood and a fishing net's main rope. With the other hand holding the sled's rope, he stepped into the deepest silence and cold before dawn.

When reaching the first fishing spot, the sun had just edged over the horizon, tinting the snow on the ice with a pale golden hue.

The A-shaped ice fishing tent woven from willow branches and the makeshift stool he left inside stood quietly there, covered by a thin layer of snow.

He advanced, first clearing the snow around the tent, then crawling in without delay. He lit the charcoal in the tin barrel, and as the first warm red glow appeared, the outside world also brightened completely.

A crucial operation he performed before leaving last night ensured seamless work today. Standing by the ice hole, he explained to the camera, "In temperatures of tens of degrees below zero, an exposed ice hole will be completely sealed within a few hours."

"To slow down this process, the key is insulation, not only from the cold air above but also disrupting the heat transmission of the ice itself."

Last night before leaving, he began by vertically inserting these spruce Tree branches, one by one, tightly into the ice hole until the entire cylindrical water body over fifteen centimeters in diameter was completely filled.

While pulling out these branches, soaked overnight in icy water, he explained, "The spruce tree's needles are very dense. Underwater, they form a huge and complex network structure whose core function is to lock in the water."

"The spruce tree needles segment the originally interconnected, free heat-conducting water column into countless tiny, independent water chambers wrapped by needles and branches."

"This significantly reduces the water's heat convection, preventing the exchange of 'warm' water at the bottom with the 'cold' water at the surface."

Lin Yu'an picked up a branch covered with ice fragments, "More importantly, these branches themselves, as poor heat conductors, become the 'skeleton' for ice crystal formation."

"The freezing process prefers to occur around these branches instead of forming a solid block of solid ice, disrupting the ice's overall structure."

After removing all the spruce tree branches from the hole, there wasn't the anticipated thick ice block formed within the ice hole.

Instead, there was a seven-to-eight-centimeter-thick layer of slush-like mixture, composed of countless tiny ice crystals and frozen leaves.

Finally, he picked up the ice drill, which didn't even need to rotate; he just forcefully pressed its guiding tip downward and stirred it a few times.

"Crack...thud..."

The seemingly thick ice cover instantly shattered like crushed snow, revealing the dark river water below. The entire clearing process took less than a minute and was almost noiseless.

He didn't rush to drop the line but first retrieved a large hard object from his backpack: a Hairy Scale Fish caught during the recent storm, its scales retaining a faint pearlescent sheen.

He had already cut it into various-sized pieces last night. The silver scales, pale pink flesh, and ice crystals mixed together emitted a strong sea smell, the unique scent of high-fat fish.

He gathered the icy, biting "fish scraps" and swept them into the dark ice hole without hesitation.

In an instant, the originally deep and calm entrance turned murky, with countless silver-white fragments spiraling downward.

More importantly, circles of rainbow-like oil slicks quickly spread across the water surface, silently dispersing enticing pheromones to the dark world beneath the ice.

He whispered to the camera, with his breath dispersing instantly, "Laying a scent trail is the most efficient method. The Hairy Scale Fish is the Arctic ecosystem's energy bar, extremely high in fat."

"In the cold water, this oily smell spreads far, creating a huge olfactory trap. For the hungry predator like the Arctic Red Spot Salmon, it's an announcement of a free feast!"

This time, the bait wasn't a rabbit's liver appearing from nowhere but a carefully selected, plump and intact Hairy Scale Fish.

He expertly hooked it up. The oil contained in the fish's belly was the ultimate lure, slowly lowering the bait into the ice hole as if planting a detonator for an underwater bomb.

"Then, we wait."

He sat steadily on the stool, his entire focus locked on the black tail feather at the rod's tip, subtly swaying with the water current.

During the wait, everything was silent, with only the wind howling across the ice.

He wasn't idle; instead, he sat by the stove, taking out the Hunting Knife and a spare piece of birch wood, with the blade scraping the wood, making a "swoosh" sound as he began carving a small wooden handle fish scaler for cleaning the catch.