Contents. 1  Inflammatory joint effusion AND Stiff hip: Causes of All Symptoms. 2  Inflammatory joint effusion OR Stiff hip: Causes of Any Symptom. 3  Inflammatory joint effusion: Causes. 4  Inflammatory joint effusion: Introduction. 5  Stiff hip: Causes. 6  Stiff hip: Introduction.
Sardines are an important part of the food chain. Jupiterimages/Photos.com/Getty Images. Sardines live in large schools that may contain thousands of fish. They typically feed on plankton and are close to the bottom of the food chain; many different kinds of predators eat sardines, including humans.
The smaller the fish, the less mercury it contains. Older, larger fish eat the small fish and therefore absorb their mercury and toxins. Sardines, such as herring, are small fish that are low in mercury and high in essential omega-3 fatty acids, calcium, vitamin D and several B-vitamins.