Spawning areas of two shallow-water penaeid shrimps (Penaeus indicus and Metapenaeus monoceros) on the Sofala Bank, Mozambique

Penaeus indicus and Metapenaeus monoceros are commercially important penaeid shrimp species in the Western Indian Ocean, supporting fisheries on the Sofala Bank, Mozambique. Despite their importance, critical gaps exist in knowledge that is relevant for management purposes. In particular, there is poor understanding of the spatial patterns in spawning for the two species. To fill this gap, we used annual data of mature female stages from research surveys conducted in late summer during January/February from 2003 to 2017. Three distinct spawning areas for P. indicus and M. monoceros were identified (northern, central and southern), all adjacent to river mouths. Spawning areas of the two species overlapped in waters shallower than 25 m, but M. monoceros spawning areas also extended to deeper (45 m) waters. Spawning areas of the two species had different spatial extents, with M. monoceros extending to the north and P. indicus to the south. The northern and central spawning areas were more persistent than the southern area. The central spawning area, however, has shifted northward for the two species during the recent period of depleted stock since 2012. We also used daily industrial catch rate data from the fishing season in March–November 2004 to 2017 to investigate annual patterns. High abundance indices of the two species were observed in the northern and central areas of the Licungo River. Catch rates, however, suggest seasonal variability with depth for the two species. This study provides new information on species-specific spawning patterns in space, which should be considered in future management approaches and spatial planning.