![]() During prolonged swimming mode, fish were able to reach further distances in warmer water conditions for all situations, due to a greater swimming speed and fatigue time, while during sprint mode, warmer conditions increased the swim speed but maintaining fatigue time. ![]() s-1 (2.55 m∙s-1 ) for 23.7 s in prolonged mode under the warmest scenario.s-1 (4.31 m∙s-1 ) during a median time of 3.4 s in sprint mode, or 12.2 BL.Results showed that a nase of 20.8 cm mean fork length can develop a median swim speed that exceeds 20.7 BL s-1 ) and temperatures (5.5, 13.5, and 18.5☌), also including the changes between swimming modes (prolonged and sprint).For this, the maximum distance, swim speed, and fatigue time were studied in an outdoor open-channel flume in the Duero River (Burgos, Spain) against three nominal velocities (1.5, 2.5 and 3 m This study aims to evaluate the volitional swimming capacity of the Northern straight-mouth nase (Pseudochondrostoma duriense), considering the possible effects of water temperature, flow velocity, and body size. However, their effects are usually disregarded in fishway engineering and management. Water temperature and flow velocity directly affect the fish swimming capacity, and thus, both variables influence the fish passage through river barriers. This predictable seasonal grouping of individuals and, more generally, the knowledge provided by such studies on how species use space have important operational value and are useful for species conservation as well as for species control. Irrespective of their size, some individuals consistently arrived earlier in the aggregation in winter and left later. The largest individuals swam more frequently back and forth to the aggregation. They became more stable with decreasing temperatures, while individuals more frequently left the aggregation, preferentially at dusk and at night, when temperatures increased. Low temperatures (below 9 ☌) triggered the formation of aggregations. In some periods during winter, all tagged fish were aggregated, which suggests that a large proportion of the lake population gathered there. These aggregations lasted 1.5–2 months and mainly took place in a single small 4 m-deep area whose environmental conditions (temperature, oxygen, substrate) did not differ from other parts of the lake. By implementing time series analysis and Cox proportional hazard models, we investigated the dynamics of these aggregations (formation, stability, dislocation), and the factors that govern it, whether external (temperature, time of the day) or specific to the fish (size, key individuals). By tracking 47 subadults and adults in a shallow lake in southeastern France, we reported a consistent aggregative behavior across four successive winters. Here we analyzed the overwintering behavior of the European catfish, Silurus glanis Linnaeus, 1758, the largest freshwater fish in Europe. Animal aggregation, particularly in large-bodied species, is both a fascinating and intriguing phenomenon.
0 Comments
Leave a Reply. |