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Promotion of initial swimbladder inflation in Pacific bluefin tuna, Thunnus orientalis (Temminck and Schlegel), larvae
Author(s) -
Kurata Michio,
Seoka Manabu,
Nakagawa Yoshizumi,
Ishibashi Yasunori,
Kumai Hidemi,
Sawada Yoshifumi
Publication year - 2012
Publication title -
aquaculture research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.646
H-Index - 89
eISSN - 1365-2109
pISSN - 1355-557X
DOI - 10.1111/j.1365-2109.2011.02933.x
Subject(s) - thunnus , biology , fishery , larva , tuna , zoology , food science , fish <actinopterygii> , ecology
Initial swimbladder inflation ( ISI ) of Pacific bluefin tuna ( PBT ), Thunnus orientalis, larvae was studied to increase the survival of cultured larvae. Experiment 1 was conducted to explore promotion and inhibition of ISI under different water surface conditions; including the use of surface skimmer to remove autogenous surface substances ( SS ), covering the water surface with liquid‐paraffin‐layer ( LP ) and oil film ( OF ), and a control (non‐treatment, NT ). Significantly higher inflation frequency was observed in SS (62.2%) than NT (11.9%), LP (2.7%) and OF (3.9%). This indicates that ISI in PBT larvae can be promoted by removal of surface substances on rearing water which inhibit larval air gulping. Experiment 2 aimed to elucidate proper day of larval age to start skimming for promoting ISI with four different periods of oil film removal: from 3 to 8 ( SF 3D), 4 to 8 ( SF 4D), 5 to 8 ( SF 5D), 6 to 8 ( SF 6D) days‐post‐hatch (dph). Significant improvement in ISI frequency was observed in SF 3D (80.2%) but the frequency was very poor in SF 4D, SF 5D, and SF 6D (17.8–7.5%). This implies the need of oil film removal without missing a narrow window, 1 day of 3 dph, to promote ISI in practical PBT larviculture.