Evidence of a pelagic nursery area for phyllosomas of the scyllarid lobster <i>Acantharctus ornatus</i> (Holthuis, 1960) (Decapoda: Achelata: Scyllaridae) in a coastal bight in South Africa

Abstract Lobster phyllosoma larvae collected during surveys over the continental shelf of eastern South Africa (southwestern Indian Ocean) were analysed to determine the role of the KwaZulu-Natal (KZN) Bight as a pelagic nursery area. Surface waters in the shallow bight and further offshore, between the 20- and 1,000-m depth contours, were sampled with plankton nets in 2018 to 2023. Phyllosomas were absent from 87.9% of 257 tows, with high variability in the remaining tows indicating a patchy distribution with abundance hotspots. Phyllosomas of four scyllarid and three palinurid species were found among 311 captured specimens. The scyllarid Acantharctus ornatus (Holthuis, 1960) was the most abundant, constituting 94.9% of the phyllosomas caught, with all nine larval stages (I–IX) present. Phylogenetic analysis using the COI and 16S rDNA gene markers confirmed that previously undescribed early larval stages in samples belonged to A. ornatus. Most A. ornatus phyllosomas were caught at shallow-bight stations, with catch rates declining steeply to the north and south of the bight and when bottom depth exceeded 100 m. Season and sampling station (nested within cross-shelf transect) were significant variables in explaining phyllosoma abundance. We provide evidence that the KZN Bight serves as a pelagic nursery area for A. ornatus phyllosoma larvae at all developmental stages, but not for other lobster species with known adult populations in the region.