The Vegan Digest (TVD) offers the following reasons why it is encouraged to give up fish. Humans’ impact on fish & ocean biodiversity is exacerbated by the extreme intensity of industries that harm Earth’s atmosphere, lithosphere, and ocean waters.

1) Fish require oxygen to survive. They consume ‘dissolved oxygen’ in the ocean waters. Fish require oxygen, just like humans.

2) Quality air in the atmosphere that provides healthy concentrations of oxygen allows for the productive mixing of ocean surfaces and the air above them; this constant mixing allows for some atmospheric oxygen to dissolve into areas of the ocean beneath the surface. Fish benefit from a healthy concentration of oxygen in the atmosphere, just like humans.

3) Colder water holds more ‘dissolved oxygen’ than warmer water. As ocean temperatures rise due to climate change, the ocean’s capacity to hold oxygen decreases. Fish are harmed by climate change, just like humans.

4) Fish benefit from plants and algae that perform photosynthesis, take in carbon dioxide, and expel oxygen into the environment. Aquatic plants as well as marine algae, such as phytoplankton, are the primary sources of the oxygen that fish consume. These aquatic plants and marine algae exist closer to ocean surfaces because they need sunlight to perform photosynthesis. Fish benefit from species, such as plants, that perform photosynthesis, just like humans.

5) Fish species that are susceptible to low-oxygen conditions become endangered. Humans often introduce disruptive species, bacteria, and other organisms through industrial practices; an example is farm-water runoff into ocean waters from large-scale, land-based animal farming. Humans’ carbon-emitting shipping vessels contaminate diverse and separate bodies of water, as they traverse oceans. Pollutants from man-made developments such as chemical compounds, sediments, and plastics end up in oceans; this endangers varied ocean species, including fish. These chemicals and sediments, from agricultural and industrial sources, can make ocean waters toxic, directly harming aquatic plants; they also make ocean waters murky and cloudy, indirectly harming aquatic plants by reducing sunlight penetration. Fish are harmed by extreme levels of pollution and unsustainable human industrial practices, just like humans.

6) Fish are observed to feel pain. Fish are known to have receptors that detect and transmit pain signals to their brains. Fish have been observed to learn to avoid situations that previously caused them pain. Fish try to escape when exposed to painful acts upon them. Fish feel pain and instinctively avoid painful sensations; they also avoid natural predators that prey on them, just like humans.

Many toxins accumulate in fish and are directly attributed to human practices. These toxins include concentrations of mercury, lead, polychlorinated biphenyls (PCBs), polybrominated diphenyl ethers (PBDEs), dioxins, and pesticides. These toxins can be lethal to humans who eat infested fish.

Overfishing results in ‘loss of ocean biodiversity,’ and billions of unintended fish are caught when fishing for an intended catch. The depletion of fish populations requires serious consideration of fish as a reliable source for human sustenance, especially in human communities that heavily rely on fish as food.