부산대학교 도서관

We have studied 872 specimens of the shrimp Alpheus lobidens De Haan 1849 collected in 2014–2015 in the Gulf of Oman, the Arabian Sea, at two littoral stations: Djod (25°26′58′′ N, 59°30′28′′ E) and Tiss (25°21′10′′ N, 60°36′08′′ E). The distance between the stations is 110 km. Alpheus lobidens is an Indo-West Pacific species and is a representative of the Lessepsian migration. It leads a burrowing lifestyle and inhabits the sandy-silt littoral with abundant boulders and gravel. As the total body length of the shrimp, measured from the end of the rostrum to the end of the telson, reaches up to 53 mm in males and 59 mm in females, it may be attributed to large species of the genus Alpheus. The total distribution of the size composition of both sexes is close to normal. Their modal sizes coincide and are equal to 32 mm. The sex ratio is close to 1 : 1 almost constantly, thus confirming the existence of monogamy, i.e., heterosexual partnership, in this species. Couples are formed upon reaching maturation at a body length of 20 mm. As a result of the mortality of egg-bearing females, after the larvae hatch from their eggs, males 25 to 29 mm long predominate in the total population. The shrimps live for about a year. In the pre and postmonsoon periods (April and November), larger shrimps (up to 44 mm long or even more) account for up to 20% of the population. Among the females, there are specimens preparing for a third or fourth spawning event. At the beginning of the monsoon period (May–June), larger specimens disappear (probably dying out?), and the littoral constantly supports two shrimp generations (sizes of 22 and 32 mm) that successively replace each other. This corresponds to two means of recruitment in the population by specimens with a body length of 12–14 mm in June and August. Females of the first group either are becoming prepared for their first mating or have just spawned for the first time; their share among females gradually decreases. Females of the second group bear eggs on pleopods with developmentally advanced embryos and maturing ovaries, preparing for the second spawning. During the monsoon period, the share of latter among females increases. However, as the beginning of the post\monsoon period approaches, they are replaced with larger specimens preparing for spawning. There are females both ready to spawn and that have freshly spawned observed in the shrimp population constantly. [ABSTRACT FROM AUTHOR]