In the end, Ao Dao went to get a magnifying glass, and the cockpit has this thing, which is a traditional tool for ship driving, which used to be used to look at nautical charts, and now there are electronic maps and GPS, but there are still magnifying glasses on board.

To the naked eye, the scales of the dragon grouper are smooth and there is nothing special on them, but if you look at it through a magnifying glass, you will find that the surface of the scales has black and white ring-like stripes, like the growth rings on the cross-section of a tree.

Ao Qianpan said: "Just count the number of laps of the black ring stripes on the scales, and add another one, that is the actual age of the fish." For example, if there are three black circles on the scales, then the actual age of the fish is four years old. ”

Ao Wenchang was surprised: "It turns out that the fish really has annual rings on its body." ”

Ao Qianpan saw that he had taught a lesson to the top students, and he was proud, so he said with a smile: "Of course." ”

"I know the reason for the tree rings, how can this fish also have long rings?" Ao Wenchang asked strangely, "Uncle Qianpan, do you know the reason?"

This stopped Ao Qianpan, he blinked his eyes and thought for a while, and finally said helplessly: "Anyway, it grows this thing, and it is the same reason as the tree grows rings." ”

Ao Qianwen knew the reason, and gave the answer with a smile: "Da Pan is right, this fish scale produces annual rings and the tree grows annual rings, the main reason is that nature changes periodically year after year, this kind of fish scale is also called bone scale, which is the evolution of the fish's dermis." ”

"In spring and summer, when the water temperature is higher and the sea is rich in bait, this is the peak growing season for the fish, they grow fast, the skin develops quickly, and the scales grow faster, so that the rings between the rings are wider. ”

"In autumn and winter, when the water temperature drops and the food decreases, doesn't the growth of the fish slow down? ”

Ao Qianpan nodded and said: "Yes, Brother Wen is right, the annual rings on these scales are wide and narrow, which represents one summer and one winter." ”

Ao Qianwen is a veteran driver at sea and knows a lot of things.

He said to Ao Muyang: "Don't look at the fish and don't speak, in fact, you can judge a lot of things on the fish through observation, and there are several ways to guess the age of the fish." Some methods do not work for certain fish, so you have to change to other methods. ”

"It is also useful to estimate the age of the fish from the number of concentric circles on the scales, and if the scales are not clear, it is also useful to estimate the age of the fish based on the vertebrae, operculum, dorsal fin, otoliths, etc. ”

"For example, flounder can use the vertebrae to calculate age, salmon can use the gill bones to calculate age, sharks can look at shark fins to estimate age, and large and small yellow croakers can use otoliths to estimate age. ”

Hearing him say so much in one breath, Ao Muyang was deeply surprised, and said, "How can you calculate through these parts?"

Ao Qianwen said: "The same, these parts of these fish will also have the same annual rings, and the appearance is clearer." ”

Ao Muyang said with a smile: "The world is full of knowledge, and the practice of human feelings is the article, and we juniors still have a lot to learn." ”

When he said this, Ao Qianwen's face lit up.

However, he still shook his head and said: "Actually, it is not very useful to learn this thing, and if you know more, you may not be able to catch fish, but you still have to rely on your ability to lead the dragon." ”

Ao Wenchang carefully counted the number of black circles on the scales, a total of thirty-seven circles, which means that the fish is thirty-eight years old.

The dragon was not very large, and the next night they came back and put away their nets, and the nets were dragged in a mess, and there were fourteen big fish hanging on them!

There are also other fish that have been hooked, and this place is indeed thriving, and there is even a yellowfin tuna hanging on it.

Catching tuna was unexpected and reasonable, and the longline fishing they had set up was originally used for tuna fishing.

There are also other fish, longline fishing has a large hook and a small hook, the big hook is used to catch large fish such as tuna, and the small hook can be used to catch some small fish.

Among the dragon barges caught this time, the largest one has a length of two meters and one five, Ao Wenchang counted the number of circles on the scales, and there were forty-eight, which means that this fish is almost fifty years old!

After putting away the nets, they put down another net, but the net was not very profitable, and they did not catch any more dragons, only some common fish in the South China Sea, such as sea catfish, bigeye snapper, and herring.

It's been four or five days since the last time fresh water was resupplied on the island, and the Dragon's Head needs to be resupplied again.

There was still some fresh water, but there was very little food and ingredients, so it was necessary to find a transit station to replenish it.

The supply island chosen by Ao Daguo is Golden Monkey Island, which is one of the few inhabited islands in the South China Sea.

Heading headwinds to the north for a while, an island came into view.

The island was much larger than the one they had visited before, nearly a square kilometre in size, which was already large for the small islands dotted around the South China Sea.

From a distance, the island is covered with forests, like a turquoise jade bead inlaid in the vast sea, which is extremely beautiful.

Compared to other seas, the boat is bustling here, with many ships coming to the island for supplies, including fishing boats, yachts, transport ships, cargo ships, and even a warship.

Seeing the long and narrow warship slowly passing by, the group took out their mobile phones to take pictures.

Ao Muyang leaned in and looked at the photos taken, and then shook his head: "What age, smartphones are everywhere, and you still take pictures with landlines?"

There is a pier extending on the island, Ao Daodao leaned the big dragon head up, he went to pay the berthing fee, and Ao Muyang took the others ashore.

Golden Monkey Island was originally called Jinshan Island, and it is said that some fishermen saw a golden mountain from afar on the sea, and found this island after the arrival of the boat.

Later, about 15 years ago, the relevant state units found that the environment on the island was very suitable for raising monkeys, so they stocked more than 10 macaques here, and just a few years later, the macaque group expanded and bred out a race.

Therefore, the island was renamed Golden Monkey Island, and today, there are not only macaques, but also short-tailed monkeys, golden snub-nosed monkeys and other monkeys.

The island has towns and inhabitants, and it is the largest maritime supply depot in the vicinity, and the inhabitants earn their living by servicing passing ships.

The small pier is bustling with pedestrians, and out of the pier is a market with some fruits and non-staple foods, and the dark-skinned islanders are enthusiastically beckoning:

"Authentic local coconuts, the water is so sweet, buy two and try them." ”

"Stinky tofu, old sausages, authentic food flown in from Shonan, delicious and affordable. ”

"Accommodation, air conditioning, fan, cold coke, except for no little sister, our hotel has everything, the IFI signal is absolutely full......"

There are many people selling things on the island, but the price is not cheap, Ao Mubing went to ask the price of coconut, and one cost 120 yuan.

Seeing this, several people were speechless: "Forget it, let's go find a restaurant to drink cold water, this price is simply slaughtering!"