2.1.2 Turnover and release of fish body carbon
The assimilated carbon in the structural pool supports animal body maintenance, growth and reproduction (He & Wang, 2006). First, part of the structural carbon is replaced by newly assimilated carbon, used and transformed during metabolism, and then released into the environment as CO2 (by respiration), DOC (by excretion or feces leakage), and PC (by defecation). Second, some of the structural carbon is used directly for reproduction (breeding) and released as PC (e.g., spawn). The carbon released from the fish body is called the body carbon release (BC release) (Figure 1).