Squid are generally considered to be at the secondary or tertiary trophic level in marine ecosystems. This can vary depending on the specific species of squid and its diet.
As carnivorous creatures, squid primarily feed on fish, crustaceans, and other smaller squid. This positions them as predators, receiving energy from the primary producers (like phytoplankton) through the organisms they consume. In simpler terms, they eat animals that have themselves consumed primary producers, placing squid higher up the food chain.
For instance, when squid eat fish that have consumed zooplankton, they are part of a more complex trophic structure. In some cases, larger species of squid may even be preyed upon by larger marine animals like sharks or whales, which indicates that they can occupy different levels of the food web depending on the context.