I've been trying to find out if sardines are farmed or if they are all wild and are only fished.
Most of the sources I find, like this page, say that they cannot be farmed:
They are not farmed, as the life cycle of the sardine does not lend itself to farming. Maybe in years to come some scientist may crack the sardine code, but not yet.
Even though a lot of sources say they cannot be farmed, there is the occasional mentioning that they are farmed, like for example:
When buying sardines we recommend you purchase the sardines that are wild caught, not farmed. Farmed sardines as well as many of the sources of fish have elevated mercury and other undesireable proteins from their food source. Sometimes in farm raised sardines the food source is chopped up meat from other fish that are high in mercury. Sardines would never have the chance to eat these large fish in the wild. Also, some fish farms feed their fish feces, other animal proteins, and foods that sardines were not designed to eat. So stick with the wild caught sardines.
After all the reading I've done, I've kind of arrived at the conclusion that most of sardines you find are fished from the wild, but there are also some that are farm raised. Is this correct? Are they farmed or not? If they are, is there any data on how much is farmed compared to how much is fished from the wild?