Abstract: Based on an external fixation method of the ultrasonic transmitter, we investigated the horizontal and vertical activities of gravid Eriocheir sinensis by the ultrasonic telemetry. There was no significant effects of external fixation of ultrasonic transmitters on the death rates of mitten crabs (P<0.05). A total of 14 tagged mitten crabs being gravid were released in December 2014, and 10, 12, 13, 9, 9, 9, 9, 6, 4, and 2 tagged crabs were tracked from late December 2014 to early May 2015, respectively. The tagged crabs were mainly distributed near north and south dams of the deepwater channel, with a trend of moving eastward. The presence frequency of tagged crabs in the midstream of the deepwater channel was greater than that in the downstream in January (P<0.05) and was greater in the downstream than in the midstream in April (P<0.05). There was significant difference between habitat depth in different months (P<0.01). The tagged crabs migrated from habitats with depth 8.25±3.35 m to that with depth 11.10±2.64 m from early January to early February, mainly inhabited in the area with depth 6.35 m from late February to early April, and inhabited in waters with depth 9.89±2.59 m in late April. Our results provide technical support for studying ecological habits and habitat locating of aquatic animals.

Key words: surface drip irrigation, soil nitrogen, tree growth, water and nitrogen coupling, stem volume