The Effect of the Seasonal Variations on the Structure of the Fish Community in Karstic Wetlands

Abstract In Mexico, “petenes” are permanent aquatic systems sustained by aquifer discharges. They are encircled by tree vegetation and are prevalent in the coastal wetlands of the Yucatan Peninsula. Owing to the karstic nature of the substratum, these floodable systems exhibit a diverse range of dynamics, primarily influenced by precipitation, the extent of swamps and marshes, and sea water intrusion. The seasonal variation in precipitation and wetland inflow significantly impacts the physical and chemical characteristics of the water, thereby affecting species abundance and diversity. This study investigated fish communities in four petenes over two years, with bimonthly sampling encompassing the three typical seasons. A total of 12 fish species were identified, including a new record for the region. The sites displayed high spatial and seasonal variation in physical, chemical and hydrological parameters. We conclude that seasonal abiotic variation and habitat characteristics are fundamental in structuring fish communities and maintaining their diversity.