A buoyancy element is for constructing a modular buoyancy system for a circularly shaped net cage. The buoyancy element includes a cage side, an opposite straight long side, and coupling sides between the cage side and the straight long side. The cage side is curved, following the periphery of the net cage.

A buoyancy element is for constructing a modular buoyancy system for a circularly shaped net cage. The buoyancy element includes a cage side, an opposite straight long side, and coupling sides between the cage side and the straight long side. The cage side is curved, following the periphery of the net cage.

A fishing tool sinking rope and modular snap fastener. A module stringing core strings a plurality of sinking elements at equal intervals. Each sinking element has a main body with two ends connected to a neck portion and terminal portion. The neck portion has a radial cross-sectional size less than that of the main body and terminal portion. A covering woven rope is interlaced to cover the module stringing core. The modular snap fastener has a bendable line and plurality of droplet-shaped hollow snap fastening members connected to two ends of the bendable line. Each hollow snap fastening member has a U-shaped gap snap fastening slot configured to fit the neck portion. The sinking element and modular snap fastener can be quickly assembled to form a string of the module stringing core serving as a center line of circular knitting machine to produce the fishing tool sinking rope.

A fishing tool sinking rope and modular snap fastener. A module stringing core strings a plurality of sinking elements at equal intervals. Each sinking element has a main body with two ends connected to a neck portion and terminal portion. The neck portion has a radial cross-sectional size less than that of the main body and terminal portion. A covering woven rope is interlaced to cover the module stringing core. The modular snap fastener has a bendable line and plurality of droplet-shaped hollow snap fastening members connected to two ends of the bendable line. Each hollow snap fastening member has a U-shaped gap snap fastening slot configured to fit the neck portion. The sinking element and modular snap fastener can be quickly assembled to form a string of the module stringing core serving as a center line of circular knitting machine to produce the fishing tool sinking rope.

A seine net assembly utilizes buoyant seine net purse rings that float above the leadline and therefore reduce the risk of the purse rings getting snagged on the bottom of the body of water. An exemplary buoyant purse ring may have a specific gravity less than 1.0 and preferably, between 0.08 and 0.96. It is desirable that the purse rings float but not be so buoyant that they cause the leadline and therefore the leadline end of the net to float. An exemplary purse ring is made out of a polymeric material such as polyethylene and most preferably ultra-high molecular weight polyethylene (UHMWPE). A polymeric purse ring may have a ring wall with a rectangular shape designed for durability and tighter packing. The width of the ring wall may be greater than the thickness.

A seine net assembly utilizes buoyant seine net purse rings that float above the leadline and therefore reduce the risk of the purse rings getting snagged on the bottom of the body of water. An exemplary buoyant purse ring may have a specific gravity less than 1.0 and preferably, between 0.08 and 0.96. It is desirable that the purse rings float but not be so buoyant that they cause the leadline and therefore the leadline end of the net to float. An exemplary purse ring is made out of a polymeric material such as polyethylene and most preferably ultra-high molecular weight polyethylene (UHMWPE). A polymeric purse ring may have a ring wall with a rectangular shape designed for durability and tighter packing. The width of the ring wall may be greater than the thickness.

A buoyancy element is for constructing a modular buoyancy system for a circularly shaped net cage. The buoyancy element includes a cage side, an opposite straight long side, and coupling sides between the cage side and the straight long side. The cage side is curved, following the periphery of the net cage.

A buoyancy element is for constructing a modular buoyancy system for a circularly shaped net cage. The buoyancy element includes a cage side, an opposite straight long side, and coupling sides between the cage side and the straight long side. The cage side is curved, following the periphery of the net cage.

A segment for use in a trawl system having a cable and a longitudinal axis. The segment has a segment body and at least one passage extending from an inner side to an outer side of the body for receiving the cable of the trawl system. The segment body is hydrodynamically shaped such that the segment is urged away from the longitudinal axis when the segment is pulled through water by the cable. A trawl net system is also disclosed.