It was originally thought that analyzing white blood cells in carp was an indicator of the age of the fish.  This study refutes that finding.

While this study is a bit hard to slog through unless you majored in Biology, it has implications for understanding the immune system and how it develops.  The greatest immunity was found in the 11-21 month old carp, while lower immunity was found in 3-9 month old carp, and the lowest immunity was in the 23-29 month old carp.  Thus, they concluded that analyzing white blood cells was not correlated with age, and that all age groups could be considered the same.

CLICK HERE to read the study.

CLICK HERE to read a 2nd study that reaches the same conclusions, but using different cell types.