Oxygen Does Not Kill Bonefish

WEBPAGE UPDATED                                   Saturday   August 1, 2020



Bonefish angled in summer bonefish tournaments need oxygen in closed boat livewells in the summer,  without enough oxygen provided continuously in livewell water, hypoxic stress, mortality and morbidity is imminent and predictable… count on it.

FACT: Many tournament anglers turn off their livewell water pumps/aerators when fishing shallow flats because electric pumps make too much noise and bonefish spook easily. When the livewell water pumps are turned off, the livewell oxygen saturation can fall quickly to dangerously low hypoxic levels resulting in additional transport stress. Hypoxia is the most serious stressor for tournament fish being  transported all day in boat livewells.

Dissolved oxygen saturation (DO Sat) levels in livewells often falls to dangerously low levels when anglers turn off livewell water pumps and aerators. There’s no fresh water pumped into the livewell continuously for long periods of time in the flats as fish consume available oxygen and excrete CO2 that increases acid concentrations in livewell water.

FACT: Most tournament fishermen that do turn off their noisy livewell pumps when fishing shallow water flats do worry continuously about the negative effects of low oxygen levels in livewells, dying and dead fish and the dead fish penalties in every summer C&R tournament.

FACT: When the livewell pumps/aerators are not humming, the fishermen’s stress always  increases. That stress is  constant and palpable, but not threatening … the captive bonefish transported in hypoxic livewells  experience far more stress than the fishermen, their stress is far more serious – it’s  life threatening stress, frank suffocation.

FACT: Administering uncontrolled supplemental oxygen is not risk free. The dose of oxygen delivered into the livewell must be regulated and controlled. Providing too much oxygen may be as deadly as not providing enough oxygen all day in boat livewells for tournament Bones.

Of course Bonefish need a steady supply of oxygen like all aerobic animals and will suffocate without enough oxygen like people. Hypoxic human neonates and some patients with advanced COPD need additional oxygen, but giving them too much oxygen may have negative results. Too much oxygen may cause blindness (retrolental fibroplasia) in neonates and suppress respiration or cause respiratory arrest in COPD patents — so be carefull with the oxygen.

Anglers using supplemental oxygen must take care to not over-oxygenate livewell water when administering supplemental oxygen. Excessive over-oxygenation in livewells may reduce recovery time post live release.

The Oxygen Edge™ regulator ensures the correct dose of oxygen is delivered when the dose is adjusted correctly. Dial in the total weight (total pounds of bonefish) of your catch on the OE regulator and be assured the correct dose of oxygen will be delivered… no over  or under oxygenation. Simply turn on the oxygen cylinder valve and adjust the correct dose of oxygen on the oxygen regulator. Dial in lbs. of fish (total lbs. of bonefish in your livewell ) on the OE regulator, not psi, LPM or fractions of LPM like pediatric medical oxygen regulators.

The correct dose of oxygen is based on the total biomass of bonefish inside the livewell. More fish require a greater dose of oxygen, less fish require a smaller dose of oxygen. The amount of dissolved oxygen the total catch needs in the livewell has nothing to do with the physical characteristics  of the livewell, the size, shape, color or volume of water in the livewell.

Bonefish and Tarpon Unlimited is made up of recreational anglers, guides, and marine industry leaders dedicated to increasing our knowledge of bonefish and tarpon biology so we can better manage these species and ensure the fisheries for future generations.

Maintaining normobaric dissolved oxygen saturation at are near 100% DO Saturation is vital for captive bonefish being transported in closed boat livewells all day and confined in tournament holding tanks as the biomass of fish changes. Fish being caught, added, transported in boat livewells and held collectively in holding tanks requires additional oxygen. Dissolved oxygen meters are used to test Dissolved Oxygen Saturation and Dissolved Oxygen Concentrations.

It is vital to know what to do when you test the DO and find the test results to be either too low or too high. What to do with the test results is very simple… If the oxygen tests too low, increase the dose of oxygen. If the oxygen tests too high, reduce the dose of oxygen… nothing to it. What ever you do, keep the livewell water continuously saturated with dissolved oxygen.

The angler and tournament organizers are both responsible for ensuring minimal safe DO Saturations while the fish are being transported, in human captivity. 100% Oxygen saturation should be maintained and monitored intermittently throughout captivity by all responsible contestants on boats and all tournament organizers including when the fish are transferred into holding tanks and release boat livewells. The oxygen saturation and concentration can only be determined by testing with a dissolved oxygen meter, then the dose of oxygen delivered may be either increased or decreased and maintained at 100% DO Saturation (+ or – 1-2%) throughout captivity. This is more critical in summer tournaments when environmental water temperatures exceed 75 F.