Reproductive biology and implications for management of the painted sweetlips Diagramma pictum in the southern Arabian Gulf

Species delimitation, molecular phylogeny and historical biogeography of the sweetlips fish (Perciformes, Haemulidae)

The subfamily Plectorhinchinae (sweetlips) is composed of poorly-known species with high commercially and ecologically values that exhibit phenotypic plasticity and various morphologies. Few studies have assessed the validity of sweetlips, intergeneric relationships and evolutionary survey in this subfamily, which have not yet been resolved. This study investigated the DNA sequences of (1) the mitochondrial COI gene to delimit species, and (2) two mitochondrial (COI and Cyt b), and one nuclear (RAG1) markers to infer phylogenetic relationships and evolutionary and biogeographic history. The molecular results could differentiate Diagramma punctatum from the other species, but failed to distinguish D. labiosum as a distinct species with considerably lower genetic distances for the COI (0.53%) and Cyt b (0.51%) markers. However, additional taxonomic investigations are required to shed light on this issue. All previously described nominal species of sweetlips in the northwest Indian Ocean were found to be well supported. The monophyly of Plectorhinchus is not supported and Diagramma pictum and D. punctatum should be assigned to the genus Plectorhinchus. The biogeographic history of Plectorhinchinae likely originated in the Indo-Pacific ca. 34 Ma (30–39 Ma; late Eocene/ middle Oligocene) and subsequently colonised the Western Indian Ocean and the Central Indo-Pacific. Maximum diversification within the subfamily occurred from the middle Miocene to Pliocene, coinciding with dispersal and vicariance events. Diversification was probably driven by both biological and geographical factors.

Demographic structure and stock status of Lethrinus lentjan in Saudi coastal waters of the Red Sea

Fishes of the family Lethrinidae form a considerable portion of the catch from both the Red Sea and the Arabian Gulf in Saudi Arabia, and the species Lethrinus lentjan (Lacepède, 1802) is one of the most important among these fishes. This study was conducted to evaluate the demographic structure coefficients, survival rate, and stock status of L. lentjan from the Red Sea coast of Saudi Arabia. A total of 593 samples were collected on a monthly basis for a period of one year from the landing site for fishing boats operating in Red Sea waters off Jeddah. The results indicated that 88.87% of the specimens were female; the maximum total length recorded was 43.5 cm with the most frequent length (14.67%) being 23–23.9 cm. The maximum age recorded for both males and females was 6 year-plus, and the 1 year-plus age category represented the majority of the samples (57.67%). The total mortality coefficient, natural mortality coefficient, and fishing mortality coefficient were 1.538, 0.315, and 1.223, respectively; all mortality coefficients in the female fishes were higher than those in the male fishes. The survival rate of males was higher (0.617) than that of females (0.214). The results of the present study indicate that L. lentjan is subjected to overfishing and a new management strategy is necessary to improve the stock status of this fish species.