Genetic diversity studies of worldwide Penaeus monodon (Fabricius, 1798), reveal the Atlantic origin of the Mediterranean Sea population of Egypt

Biological invasions are among the major stressors on aquatic ecosystems. It can significantly affect species distribution and native biodiversity. Penaeus monodon invasions are frequently reported worldwide, leading to the establishment of several breeding populations. P. monodon was first recorded and morphologically identified in the Mediterranean Sea in Egypt in 2016. The current investigation aimed to assess the genetic diversity and origin of a P. monodon population from the Mediterranean Sea, Egypt, and to evaluate the genetic diversity of P. monodon populations worldwide using two different mitochondrial barcode regions, cytochrome c oxidase subunit I (COI) and 16S rRNA. Different P. monodon populations with Indo-Pacific and Atlantic origins were included for these purposes. Based on the COI, 16 haplotypes were recorded in nine P. monodon populations, with 45 polymorphic sites. High haplotype diversity (Hd = 0.7575) and high nucleotide diversity (pi = 0.0261) were also recorded. Based on 16S rRNA, 37 haplotypes were recorded in seven P. monodon populations, with 72 polymorphic sites, high haplotype diversity (Hd = 0.9838), and high nucleotide diversity (pi = 0.0985). The populations of P. monodon within its species range (of Indo-Pacific and Atlantic origins) shared many haplotypes, indicating shared lineages. Barrier analysis has divided the studied populations into groups in which Egypt was grouped with populations of Atlantic origin (based on COI and 16S rRNA) and supported with evidence of the Atlantic origin of the Egyptian population. This study showed that the Suez Canal is not the inevitable route for this species to invade the Mediterranean; therefore, precision must be exercised when determining the route of entry of any species into the Mediterranean Sea. The frequent introductions/invasions of the P. monodon population significantly contributed to the observed patterns of genetic diversity and favored its ability to adapt, colonize, and expand.