Oxygen consumption of Penaeus vannamei is influenced by environmental factors such as (1) the combination of salinity and temperature in relation to (2) body size and (3) health condition of the shrimp e.g. presence of gill associated disease problems manifested by gill lamellar hypertrophy, hyperplasia, and fusion, branchial necrosis, and melanization whether localize or diffuse, unilateral or bilateral.
https://www.scielo.br/scielo.php?pid=S1679-87592009000400005&script=sci_arttext36 (Ctistei Bett and Luis Vinatea, 2009)
Also (4) depending on the activity of Penaeus vannamei, it will either consume more oxygen or consume less, e.g. shrimp that is swimming actively against the current in front of the paddlewheel will have more oxygen consumption than a shrimp at rest in the corner of the pond. Then too, the shrimp will consume more oxygen during feeding frenzy when the shrimp are hyperactive and fighting over the feeds using their 3rd pair of walking legs especially in high-density stocked ponds where space is limited.