In large-scale industrial Purse Seining, once a massive school of pelagic fish (sardines, menhaden, anchovies, tuna) is gathered and concentrated into the purse seine bunt alongside the vessel, large centrifugal fish suction pumps are lowered directly into the net pocket to rapidly pump fish and seawater directly into chilled sea water (CSW/RSW) holds without bruising.

Gill netting is the most ubiquitous, universally practiced fishing method across marine, estuarine, and inland waters worldwide. Gill nets are passive, highly size-selective, low-cost, fuel-efficient, and easily deployed from small non-motorized canoes to large commercial driftnet vessels.

In fishing gear technology, the Hanging Coefficient ($E$) is defined as the ratio of the length of the framing line / head rope ($L$) to the fully stretched length of the netting webbing ($L_0$) hung on it:

Gear selectivity characteristics across commercial fishing gears:

• sigmoid (logistic S-shaped) selection curve is characteristic of trawl codends, where retention increases monotonically from 0 to 100% as fish body size exceeds mesh opening.
• Asymptotic curves describe knife-edge selectivity or cumulative asymptotic gear retention.
• Linear curves do not represent physical gear hydrodynamic interactions.
• standard gillnet exhibits a unimodal, symmetrical bell-shaped (normal/Gaussian) selectivity curve. Fish that are too small easily swim through the mesh openings without capture, while fish that are too large cannot penetrate past their opercular girth to become wedged, meaning capture efficiency is maximized strictly within an intermediate, narrow length/girth range.