A tank for water has a bottom and a surrounding wall with an inside and an outside. In a lower portion, the wall is provided with a hatch casing positioned in a hatch opening extending through the wall for access by personnel from the outside to the inside of the tank. The hatch casing is provided with a hatch with an inside and an outside. The hatch in a closed position closes the hatch opening in a liquid-tight manner. The inside of the hatch is flush with the inside of the wall when the hatch is in the closed position. A method for giving personnel access to the tank through the hatch opening is also described.

A device for high density culture of fish larvae includes: a nursery tank, a first aerotube, a standing mesh drain pipe, and a dual-drain recirculating water treatment system. The nursery tank is a rounded corner tank or a polygonal tank without dead corners. The first aerotube is disposed around the bottom of the inner wall of the nursery tank. The standing mesh drain pipe is disposed in the center of the bottom of the nursery tank. The dual-drain recirculating water treatment system includes a first water treatment system and a second water treatment system. The first water treatment system and the second water treatment system are symmetrically disposed on both sides of the nursery tank, respectively. The first water treatment system is configured to purify upper layer water of the nursery tank, and the second water treatment system is configured to purify lower layer water of the nursery tank.

Monitoring systems and methods for tracking movement of one or more animals in an enclosure, such as a fish tank, include introducing various stimuli, such as food, light, and auditory stimuli, and tracking the movement of the animals in response to these stimuli. Movement patterns of the animals can be determined and analyzed from data obtain from cameras that record images/videos of the relevant portions of the enclosure.

A screen for a fluid tank, the screen comprising: at least one expandable screen section configured to be positioned on a fluid tank to permit movement of the at least one expandable screen section relative thereto, wherein the at least one expandable screen section is configurable between an expanded state and a contracted state. There is also provided a tank having a screen arranged vertically movable therein and a method for moving aquatic animals out of a tank, the method comprising: arranging the at least one expandable screen section in or on the tank in the contracted state; bringing the at least one expandable screen section to the expanded state; and moving the screen relative to the tank to crowd the animals towards an outlet in the tank.

A watercraft for breeding aquatic organisms, including an aquaculture facility and a device for feeding water into the aquaculture facility so that water intended to be fed into the aquaculture facility can escape from a body of water in which the watercraft is floating. A feed opening for receiving the water from the body of water is open in the longitudinal direction of the watercraft and/or is arranged below a water line of the watercraft. The feed opening is arranged on the hull of the watercraft, preferably on the bow. The watercraft includes a device for letting out water from the aquaculture facility to the body of water. An outlet opening of the outlet device is open in the longitudinal direction of the watercraft and/or is arranged below the water line of the watercraft. The outlet opening preferably being arranged on the hull of the watercraft, on the bow thereof.

A problem to be solved by the present invention is to prevent an aquatic creature from jumping out of a water tank without directly contacting the aquatic creature; and a jump-out prevention device for the aquatic creature, which can solve or reduce the problem, is provided. The jump-out prevention device for the aquatic creature includes electrode parts arranged along an inner perimeter of a water tank for keeping the aquatic creature; and a power supply part electrically connected to the electrode parts, and configured to apply electrical pulses to the electrode parts. The electrode parts extend in a horizontal direction partially or entirely over the inner perimeter of the water tank, and are arranged in a predetermined underwater region in the water tank. The electrical pulses are applied to the electrode parts.

A problem to be solved by the present invention is to prevent an aquatic creature from jumping out of a water tank without directly contacting the aquatic creature; and a jump-out prevention device for the aquatic creature, which can solve or reduce the problem, is provided. The jump-out prevention device for the aquatic creature includes electrode parts arranged along an inner perimeter of a water tank for keeping the aquatic creature; and a power supply part electrically connected to the electrode parts, and configured to apply electrical pulses to the electrode parts. The electrode parts extend in a horizontal direction partially or entirely over the inner perimeter of the water tank, and are arranged in a predetermined underwater region in the water tank. The electrical pulses are applied to the electrode parts.

Aspects of the present disclosure involve hydraulic systems and methods for altering a flow of a body of water, such as a river, channel, and/or other flowing or uncontained bodies of water. In one aspect, a hydraulic system provides a velocity barrier for the impedance of aquatic organism migration. More particularly, the velocity barrier may be adapted based on the swimming capabilities of one or more aquatic organisms to impede migration. The aquatic organism may be one or more species of fish, such as species sea lamprey (Petromyzon marinus). The example implementations shown and described herein reference the restriction of the sea lamprey. However, it will be appreciated that other aquatic organisms could be restricted by the presently disclosed technology, for example, with different hydraulic targets depending on swimming capabilities.

Aspects of the present disclosure involve hydraulic systems and methods for altering a flow of a body of water, such as a river, channel, and/or other flowing or uncontained bodies of water. In one aspect, a hydraulic system provides a velocity barrier for the impedance of aquatic organism migration. More particularly, the velocity barrier may be adapted based on the swimming capabilities of one or more aquatic organisms to impede migration. The aquatic organism may be one or more species of fish, such as species sea lamprey (Petromyzon marinus). The example implementations shown and described herein reference the restriction of the sea lamprey. However, it will be appreciated that other aquatic organisms could be restricted by the presently disclosed technology, for example, with different hydraulic targets depending on swimming capabilities.

Aspects of the present disclosure involve hydraulic systems and methods for altering a flow of a body of water, such as a river, channel, and/or other flowing or uncontained bodies of water. In one aspect, a hydraulic system provides a velocity barrier for the impedance of aquatic organism migration. More particularly, the velocity barrier may be adapted based on the swimming capabilities of one or more aquatic organisms to impede migration. The aquatic organism may be one or more species of fish, such as species sea lamprey (Petromyzon marinus). The example implementations shown and described herein reference the restriction of the sea lamprey. However, it will be appreciated that other aquatic organisms could be restricted by the presently disclosed technology, for example, with different hydraulic targets depending on swimming capabilities.