Wiping out oceans
World fisheries are suffering. Giant ships are now using state-of-the-art sonar to pinpoint schools of fish quickly and accurately. Using methods like bottom trawling and long-lining, these fleets are capable of wiping out entire fisheries in a single season. As per the United Nations, over 80% of global fishing stocks are either fully depleted or overexploited.
As disturbing is the large number of ‘by-catch’ sea animals that are killed every year, as it is not possible for fishing nets to target only those fish that are meant to be eaten. Sharks, sea turtles, birds and other non-target fish, including many endangered species, that get tangled in nets are termed "bycatch" and are thrown back into the sea, dead or injured.
Aquafarms: Living conditions
Rising demand for fish and rapidly depleting oceans, has resulted in aquaculture providing almost half of all fish consumed globally, with a rapidly increasing share.
Water Quality: The body of a fish is always in contact with water and a fish uses its gills to extract oxygen out of water. This makes fish highly sensitive to water quality and pollution. In aquaculture, the water quality is consistently deteriorating due to the fish's respiration and waste production, depriving the fish of adequate oxygen supply (hypoxia) and triggering stress responses. Accumulation of waste leads to an increase in levels of ammonia, nitrate, nitrite and suspended solids, leading to impaired gill and kidney function.
Water Temperature: A fish's body temperature is typically within a few degrees of the water temperature. Any changes in water temperature leads to a change in the fish's metabolic rates and demand for oxygen. While increasing temperatures is linked to hypoxia, lower temperatures can supress the immune system and lead to lower feeding.
Lighting: In factory farming, artificial lighting is used to control the photo-period (extending daylight hours to increase rate of growth and faster maturity), with some species being exposed to 24 hour lighting to speed growth even further. Artificial photo-periods can effect the immune system and disease susceptibility in fish. Rapid shifts in light intensity can trigger predator / panic responses, increasing injuries through unintentional collisions.
Stocking Densities: Overstocking diminishes the ability to fish to display natural behaviours, while increasing the exhibition of undesired ones. Overstocking reduces the ability of sub-ordinate fish to avoid dominant individuals, inhibits the formation of smaller groups or schools and ability to swim unimpaired. Aggression resulting out of overstocking, leads to increased stress levels, increased mortality rates and adverse physiological effects on fish.
Diseases: Conditions in aquaculture (including overstocking, poor water quality, unnatural lighting and changing water temperatures) contribute to diseases and increased morality rates. Poor water quality can lead to gill injuries, increasing susceptibility to bacterial infections. This bacterial growth hinder the ability for the gills to absorb oxygen and can be fatal. Overstocking directly increases the levels of parasitic infections, with parasites infecting every part of their host – feeding on their gills, infecting the blood, intestines and nearly every other organ.
Fish are starved before transport, both to (a) eliminate the need of fish to defecate during transport, protecting water quality (b) minimize carcass contamination during gutting. During periods of food deprivation, fish are known to engage in cannibalistic behaviours such as nipping at eyes and fins of other fish.
Fish are highly sensitive to water quality and temperatures. During transport, fish are moved through different environments at different temperatures, resulting in significant increases in stress levels and mortality amongst transported fish.
Overcrowding (already an issue in aquaculture, which gets more accentuated during transport) leads to injuries through consistent collisions amongst fish, increased aggression and fights and increased stress levels in fish.
When many fish are netted together, the weight of the fish above causes serious injuries to the fish at the bottom of the pile. In modern fishing fleets, thousands of fish pile up crushing the ones below with an overwhelming force. The frightened suffocated fish struggle and attempt to escape from the net causing further injuries.
Removing fish from water and asphyxiating them in air, lead to very strong escape behaviours and severe stress responses. Once out of the water, fish suffocate rather like we would do if held underwater. In their death throes fish writhe, gasping and flapping their gills as they desperately try to get oxygen.
Anyone who has ever been unable to breathe even for a short time will understand that this is a terrifying experience. For fish, the time taken to reach unconsciousness varies based on temperature and metabolic rates – from a few minutes at high temperatures to as high as 10-15 minutes at lower temperatures.