Molecular taxonomy of fish larvae in the Northwestern Arabian Gulf: a baseline study from Kuwait's first marine protected area

Sulaibikhat Bay, a shallow embayment dominated by tides and extensive mud flats along the northern coast of Kuwait Bay, serves as a crucial nursery ground for various commercially important species of finfish and shellfish in the Northwestern Arabian Gulf (NWAG). As the location of Kuwait's inaugural marine protected area (MPA), Sulaibikhat Bay plays a vital role in fostering numerous fish and marine invertebrate species of commercial importance in the Arabian/Persian Gulf. Accurate identification of larval specimens from this habitat is essential for understanding their spawning dynamics and recruitment process. However, limitations in taxonomic identification hinder scientific understanding of fish larval recruitment. To address this, our baseline study employed an integrated taxonomic approach, combining conventional morphology with molecular techniques. Fish larvae collected from the MPA and surrounding waters in Spring 2022 were identified up to the genus and species levels using partial gene sequencing of 16S rRNA and mitochondrial cytochrome oxidase (COI) genes. Morphological analysis indicated the prevalence of Sparidae, Sillaginidae, and Dorosomatidae families. Molecular analysis confirmed the presence of these families and identified two species, Crenidens crenidens (Sparidae) and Nematalosa nasus (Dorosomatidae), along with two genera, Diplodus sp. (Sparidae) and Sillago sp. (Sillaginidae), which exhibited maximum similarity to available COI sequences of Diplodus sargus, and Sillago maculata, respectively. This represents the first baseline molecular study on fish larvae from NWAG, laying the groundwork for future in-depth analyses with more larval specimens and spatiotemporal samplings from the entire exclusive economic zone (EEZ) of Kuwait in the Arabian/Persian Gulf.