Biological observations on the introduced prawns in Lake Quarun (Egypt)

Abstract

      Lake Quarun (a closed inland lake) is considered as the best site for grownig and reproducing shrimps, after five years of transplantation with post larvae (PL 30).

      Penaeus kerathurus FORSKAL, Metapenaeus monoceros FABRICIUS and Metapenaeus stabbingi NOBILI are considered the most adapted species.

      The shrimp production of Lade Quarun in 1987 was about 44% of the total fish production. The rich benthic fauna and abundance of plankton as well as the suitable topography and environmental conditions play important roles in the reproduction behaviour of these species. Growth in weight and length of samples from lake Quarun for M. stebbingi was higher than those collected from their natural habitats (in the Mediterranean Sea). This was not noticed in the other two species. The continous decrease in abundance of M. monoceros and P. kerathurus in lake catch is expected to be due to many reasons, as the lack of migration behaviour, temperature effect on early stages mortality, and the intraspecific and interspecific competition for food and space. More studies are needed to increase the efficiency of producing shrimps from lake Quarun.