Weight Growth of Atlantic Bluefin Tuna (thunnus Thynnus, L. 1758) as a Result of a 6-7 Months Fattening Process in the Central Mediterranean

The study calculates the fork-length to round weight (L-W) relationship and condition index (K) of fattened bluefin tuna for 6-7 months in a tuna farm in western Greece and compares these morphometric parameters with those of wild bluefin tuna using the set of measurements obtained in the context of the EU-funded research projects REPRO-DOTT & SELF-DOTT. The L-W relationship and K values found were very different to those of the wild bluefin suggesting a minimum weight gain of 27.2-32.6% and 33.8-37.8% for size classes 205-245cm and 255295cm during the fattening period through improvement of condition and fat content of the fish. The results are consistent with similar studies conducted by other authors in the past, however the actual weight gain rates in farming conditions may be bigger because the above method does not take into account the length increase of the fish during the fattening period and additional weight gain resulting from structural growth.