Many novice fishermen and spearfishing enthusiasts often wonder about the exact time of activity of crayfish, since knowledge of the biorhythms of these arthropods directly affects the success of fishing. Cancers They lead a predominantly nocturnal lifestyle, but their exit to shallow water and to the shore is not a random process, but is subject to strict natural laws and environmental changes. Understanding when exactly crustaceans leaving their shelters, allows not only to increase the catch, but also to better navigate the state of the reservoir, since these creatures are excellent bioindicators.
There is a misconception that crayfish crawl onto land only in the event of an acute lack of oxygen or water pollution, although in reality a massive emergence can also occur in absolutely clean water bodies during certain periods of the year. Most often this is due to molting, searching for a mating partner, or a sudden change in atmospheric pressure that forces them to migrate to more comfortable areas. The peak of crayfish activity occurs from 23:00 to 03:00 at night in warm, windless weather with high humidity, when there are significantly fewer predators on the shore.
In this article, we will analyze in detail the seasonal characteristics of crayfish behavior, the influence of the phases of the moon and weather conditions on their migration, and also consider the biological reasons that prompt them to leave their native element. You will find out why on some nights they literally crawl out of the water in dozens, while on others they sit in holes, ignoring even the most delicious bait. This knowledge will be the key to understanding the life of the reservoir and will help you plan your outings with maximum efficiency.
Seasonal migrations: spring awakening and summer activity
With the onset of spring, when the water temperature in rivers and lakes begins to steadily rise above 10 degrees Celsius, crayfish emerge from winter torpor. During this period, which usually occurs at the end of April or May depending on the region, they begin to actively search for food to recuperate after a long winter. Spring exit is often chaotic, as arthropods explore the coastal zone in search of organic remains and young vegetation.
In summer, the activity of crayfish shifts towards the night hours, when the water cools down a little after a hot day. It is during the summer months, especially June and July, that one can observe mass strandings associated with the molting period, when the shell becomes soft and requires renewal. At this time, crayfish become especially vulnerable and try to stay closer to reed or reed thickets, where it is easier to find shelter and food.
It is important to note that during the spawning period, which in females can shift depending on climatic conditions, behavior changes. Females with eggs under their tails are less likely to leave deep burrows, while males actively patrol shallow water in search of partners. Atmospheric pressure in the summer it plays a decisive role: before a thunderstorm or a sudden change in weather, crayfish can crawl ashore long before sunset, sensing changes in the electromagnetic field and the composition of the water.
- 🌡️ Water temperatures above 15°C stimulate maximum activity and access to shallow water.
- 🌙 The full moon often reduces the activity of crayfish, as they hide from bright light.
- 🌧️ Cloudy and quiet weather contributes to an earlier exit from shelters.
- 🌿 The presence of dense coastal vegetation is a prerequisite for a mass exit.
⚠️ Attention: If you observe a mass emergence of crayfish on the shore during the day in the summer heat, this may indicate a sharp deterioration in water quality or a lack of oxygen, which is an alarming signal for the ecosystem of the reservoir.
Nocturnal lifestyle: influence of time of day and illumination
The main period of activity of crayfish occurs in the dark, which is dictated by the instinct of self-preservation. These animals have an excellent sense of smell and touch, but their vision does not allow them to navigate effectively in bright light, making them easy prey for birds and other predators. Twilight time is a transitional stage when crayfish are just beginning to leave their burrows, carefully exploring the entrance.
The most intense bite and landing on the shore is recorded between 22:00 and 02:00 am. At this time of day the water is usually calm and noise pollution from human activity is minimal. Crayfish crawl out onto the shallows to find food, and it is during these hours that they are easiest to detect with the help of a flashlight, the rays of which for some reason they ignore or freeze in place.
Moon illumination has a dual effect on the behavior of crustaceans. On the one hand, on bright moonlit nights it is easier for them to navigate, but on the other hand, they become more visible to predators, so they can hide deeper in the grass. Complete darkness or cloudy weather hiding the moon often provokes crayfish to make more daring forays far from the water, sometimes at a distance of several meters from the shore.
It is worth considering that crayfish are very sensitive to artificial light. The bright light of headlights or powerful spotlights can frighten them and force them to retreat into the water, so experienced fishermen use red filters on flashlights or try to move silently and without sudden flashes of light. Biorhythms Cancers are strictly tied to the solar cycle, and a shift in their sleep phase is almost impossible without extreme environmental changes.
Weather factors: how pressure and wind affect output
Atmospheric pressure is one of the key factors determining the behavior of crayfish. When there is a sharp drop in pressure, which usually precedes rain or thunderstorms, crayfish can behave restlessly and crawl ashore in search of more stable conditions. However, too strong a drop in pressure can, on the contrary, drive them into deep holes, where they wait out bad weather.
The wind also plays an important role: in windy weather, when a wave rises on the water and muddies the bottom, crayfish prefer to sit in shelters. The noise of the surf and the vibration of the water disorientate them, preventing them from hunting and smelling normally. Calm weather or a light breeze are considered ideal conditions for crayfish to come ashore, as the water remains clear and calm.
Air temperature indirectly affects the activity of crayfish through heating or cooling of the upper layers of water. On warm, humid nights, especially after rain, crayfish feel most comfortable and can crawl quite far into the grass. On the contrary, a cold front or a sharp drop in temperature forces them to go to depths where the water temperature is more stable.
Why do crayfish crawl out before it rains?
There is a theory that before rain, the chemical composition of water and the content of dissolved gases changes. Crayfish, being highly sensitive, react to these changes and can crawl ashore, fleeing possible death or changes in acidity, or simply looking for more comfortable living conditions.
The table below shows the dependence of crayfish activity on various weather conditions:
| Weather condition | Effect on activity | Probability of landfall |
|---|---|---|
| Quiet warm night | Positive | High |
| Strong wind and wave | Negative | Low |
| Before a thunderstorm (pressure drop) | Ambiguous | Medium/High |
| Clear moonlit night | Average | Average |
| Fog and high humidity | Positive | Very high |
Biological reasons: molting, reproduction and foraging
One of the main biological reasons for crayfish coming ashore is the molting process. During this period, the old shell becomes tight, and the cancer must shed it in order to grow. Shedding - This is a critical moment in the life of a crayfish, when it becomes soft and defenseless, so it often looks for secluded places in coastal grass or shallow water, where there are fewer large predators.
During the breeding season, males become extremely active and aggressive, patrolling their domains and searching for females. They can crawl into shallow water and