National inventory and ecological status of marine crustaceans in Libyan Waters, Southern Mediterranean

Abstract

The Libyan coast provides an ecological habitat supporting a diversity of marine crustaceans. This study aims to assess the diversity, spatial distribution, and ecological status of crustacean species inhabiting Libyan marine waters. Data were compiled from a comprehensive review of unpublished scientific surveys, technical reports, and biological samples collected along various parts of the Libyan coast during two main sampling periods: January 2005 to March 2006, and January 2013 to January 2017. Additional benthic samples were obtained from a shipwreck site located on a sandy seabed at a depth of 31 meters off the coast of Tripoli during both winter and summer seasons in 2020. A total of 357 crustacean species were identified, encompassing five taxonomic classes and 138 families. Species richness was highest in the eastern coastal region. The class Malacostraca represented the most taxonomically diverse group, comprising 62.32% of the identified families and 162 species (45% of the total species count). This was followed by Hexanauplia, which accounted for 31.88% of the families and included 183 species (50.83%). The majority of recorded species (94.40%) were native to Libyan waters, while 5.60% were classified as non-indigenous. These non-indigenous species, primarily localized along the coast, offer critical insights into patterns of marine bio-invasion and species establishment in the south-eastern Mediterranean Sea. This study provides a comprehensive evaluation of crustacean biodiversity along the Libyan coast, contributing significantly to baseline data for regional marine biodiversity assessments. It also highlights key distributional patterns and potential ecological implications of non-indigenous species in this underexplored sector of the Mediterranean basin.