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Factors affecting the feeding response of larval southern bluefin tuna, Thunnus maccoyii (Castelnau, 1872)

journal contribution
posted on 2023-05-19, 06:52 authored by Pollyanna Hilder, Cobcroft, JM, Battaglene, SC
Southern bluefin tuna, Thunnus maccoyii, are cultured in Australia following collection of wild juveniles. Hatchery culture from egg is in the experimental stage. High early mortality has hindered the production of quality juveniles in the hatchery. This study investigated the visual capacity of T. maccoyii during early larval ontogeny in order to describe the best larval rearing conditions to produce high-quality seed stock. Functional visual ability, determined through behavioural experimentation, identified the effect of light intensity, prey density, turbidity, tank colour and turbulence on the feeding response. Larvae were visually challenged to feed under a range of conditions in short-duration (4 h) feeding experiments. Feeding performance was measured as the proportion of larvae feeding and the intensity of feeding. First-feeding performance was positively affected by increasing prey density and lower turbidities and unaffected by light intensity, tank colour, turbulence, prey size and larval density. The key findings from feeding experiments on 6 and 9 dph larvae was that as T. maccoyii aged, lower light intensities and higher prey densities significantly increased feeding performance. In addition, the study has identified that high light intensity and high air-driven turbulence induced significant mortality. The proficient first-feeding response indicated that early mortality common in culture is unlikely to be associated with a failure to initiate feeding. Our findings show the use of low light intensity has the potential to significantly improve survival and feeding response during the first two critical weeks of culture, when the major bottleneck in hatchery production is currently experienced.

History

Publication title

Aquaculture Research

Volume

48

Issue

6

Pagination

2752-2766

ISSN

1355-557X

Department/School

Institute for Marine and Antarctic Studies

Publisher

Blackwell Publishing Ltd

Place of publication

9600 Garsington Rd, Oxford, England, Oxon, Ox4 2Dg

Rights statement

Copyright 2016 John Wiley & Sons Ltd

Repository Status

  • Restricted

Socio-economic Objectives

Aquaculture tuna

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