Taxonomy, spatial and size distribution of tuna larvae in their spawning area in the Western Mediterranean
2023
Bouaziz, Salsabil
This study focuses on the monitoring of Atlantic bluefin tuna (Thunnus thynnus), bullet tuna (Auxis rochei) and albacore (Thunnus alalunga) larvae in their spawning habitats around the Balearic archipelago using ichthyoplankton surveys. The study examined the capture of tuna larvae of different stages using a Bongo90 with 1000μ nests, in comparison with the traditionally used Bongo 90 with 500μ nets. The results show that both nets collect similar densities of Bluefin tuna larvae, but the B90/1000 net caught more post-flexion larvae. The study also investigates the effects of hydrographic variables on tuna larvae's distribution, finding that all hydrographic variables had a significant effect on Bluefin tuna larvae densities. However, due to the low capture of ALB and BT, GAMs could not be applied and only general linear regression was tested. Results will improve sampling strategies to respond to current challenges on genetic studies and development of larval abundance indices.
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