Albacore tuna larval occurrence in the Southwest Indian Ocean and associated species

Improving our knowledge about albacore tuna reproduction biology is critical for stock
management for sustainable fisheries of this presumed to be overfished species. While most
of the stock assessment data are from commercial fisheries landed adults, here we present
preliminary results of distribution and abundances of larval Albacore tuna (Thunnus.
albacares) from Southwestern Indian Ocean near Reunion Island. Surface and subsurface
tows were conducted in the spawning habitat of albacore and collected tuna larvae were
quantified, measured, visually identified, and genetically confirmed using multiplex PCR
using primers for six tuna species: kawakawa (Euthynnus affinis), skipjack (Katsuwonus
pelamis), albacore (Thunnus alalunga), yellowfin tuna (Thunnus albacares), bigeye (Thunnus
obesus), and Atlantic bluefin tuna (Thunnus thynnus). Albacore larvae were the most
numerous and most abundant from our collection (N = 214, 68.21% of total tuna density).
Using the reported age-length relationship for T. alalunga from the Mediterranean Sea, our
specimens are estimated to be 0–6 days post hatch. Further early life history research is
needed to determine larval indices to better estimate larval survival and recruitment into
fisheries.