In the livestock industry, feed conversion ratio is an important concept, referring to the ratio of feed consumed by animals to the growth of their body mass.
For example, a conversion ratio of 1.5 means that for every 15 pounds of feed, an animal gains 10 pounds in body weight.
Different animals exhibit significant variations in conversion ratios: pigs are around 3 or higher, sheep range between 4 and 5, and cattle can even exceed 6.
Frogs, notably, have an exceptionally high conversion ratio, approaching 1, which means they gain one pound in body weight for each pound of feed consumed.
On the other hand, fish may have a conversion ratio that is lower than 1, indicating they require less feed to increase in weight.
This is not contrary to scientific principles but rather due to the availability of natural food resources in their environment, such as algae, other aquatic organisms, and even microorganisms imperceptible to us.
For poikilothermic animals, their basal metabolic rate is extremely low, approximately one-tenth that of homeothermic animals.
Take crocodiles, for example; they can survive for months after a hearty meal without eating again, closely tied to their low energy expenditure.
Similarly, fish thrive in natural environments due to their low energy consumption.
For instance, lifting 1 kilogram of water to a height of 1000 meters requires only about 10,000 joules (10 kilojoules) of energy, enough to raise the water temperature by 2.4 degrees Celsius.
In contrast, homeothermic animals expend most of their energy maintaining body temperature rather than activity.
Therefore, one reason fish are less likely to die from hunger is their extremely low energy consumption.
Fish possess various adaptation strategies enabling them to survive in extreme environments.
Firstly, fish have a very low basal metabolic rate, requiring no maintenance of body weight or temperature, even capable of entering a state of dormancy with minimal energy consumption in cold water conditions.
Secondly, fish can utilize body fat, muscles, viscera, and even bones to cope with prolonged food shortages, which is impossible for mammals.
Furthermore, abundant natural food resources in water bodies, such as algae, tiny aquatic insects, and organic debris settling from the air, provide additional energy sources for fish.
Studies have shown that some fish caught in the wild can survive for extended periods without artificial feeding, maintaining a slow growth rate but sustaining good survival conditions.
From a human perspective, what may appear as resource-limited environments in aquaculture ponds can actually be a rich food paradise for fish.
In such environments, fish may form a kind of "utopia for fish," enjoying physical growth while demonstrating social behaviors like courtship and communication.
This comparative perspective helps us better understand the adaptive capabilities and survival strategies of fish in aquaculture environments.
It is commonly believed that fish are less likely to die from hunger, but this is not entirely accurate.
In artificial breeding environments, fish have relatively small viscera relative to body size and a simple digestive system.
Prolonged starvation can lead to intestinal problems and even fatal intestinal obstruction.
However, in natural water bodies, fish can rely on abundant microorganisms to support the food chain, thereby maintaining their long-term survival.
Comments