This provides another shallow water habitat where mangrove forests and estuarine fish thrive. Oysters naturally grow in estuarine bodies of brackish water. Fish that occasionally enter freshwater and estuarine environments include snook, jewfish, mangrove snapper, and mullets. Marine fungi are species of fungi that live in marine or estuarine environments. These become concentrated in the surface film and in marine sediment, especially estuarine mud. The pupping grounds are in coastal and estuarine waters. Bayelsa has a riverine and estuarine setting. Palo Alto has a number of significant natural habitats, including estuarine, riparian, and oak forest. Two of the main characteristics of estuarine life are the variability in salinity and sedimentation. Two of the main challenges of estuarine life are the variability in salinity and sedimentation. This probably stems from poor visibility in fluvial and estuarine environments. These forests have saltwater crocodiles, estuarine and marine turtles, and a number of bird species. Goa has more than 40 estuarine, eight marine, and about 90 riverine islands. OTC systems may be used on very large rivers or at coastal and estuarine sites. Juveniles and subadults commonly school, both in marine and estuarine environments.