To read more, visit our blog, St. Johns River Fun Facts. "The salinity level in the river is pretty high between State Road 46 and 50," Van Horn said. St. Johns River , the largest in eastern Florida, is about 248 miles long and is an unusual major river in that it flows from south to north over most of its length. FWRI biologists encounter many saltwater species along the St. Johns River. St. Johns River Cruises out of Blue Spring State Park is one of many tourist excursions along the 310-mile river (the state’s longest), including a sternwheel paddleboat tour out of St. Johns Rivership Co. in Sanford to the south. Salinity, water, unfiltered, parts per thousand Most recent instantaneous value: 0.7 01-21-2021 03:00 EST Add up to 2 more sites and replot for "Salinity, water, unfiltered, parts per thousand" The St. John's River Operational Forecast System (SJROFS) has been implemented by NOAA's National Ocean Service (NOS) to provide the maritime user community with short-term predictions of water levels, water currents, water temperatures and salinity of the St. John's River. During the winter season, hundreds of these gentle sea cows inhabit the spring’s surface much to the joy of onlookers. Some fish move between the two for other reasons, like looking for food. The St. Johns River is the perfect place to introduce your little ones to the magic of hooking this tasty fish, thanks to its calm waters and bustling, year-round Crappie population. Diadromous fish move from saltwater to freshwater or vice-versa to mate and grow to maturity. Via Salt Springs Run (launch at Salt Springs Marina) Via the Ocklawaha River (area is unavailable) (launch at SR 19) plus the historic Fort Gates Ferry crossing Although Lake George is called a lake, it is actually the widest spot in the St. Johns River, and is extremely shallow in places. Saint Johns River is a 355.2 mile stream.The St. Johns River (officially Saint Johns River, but commonly spelled St. John's River) is the longest river in the U.S. state of Florida, stretching 310 miles (500 km) from Indian River County to the Atlantic Ocean in Duval County. Among the tributary sites, annual mean salinity was highest at Clapboard Creek, the site closest to the Atlantic Ocean, and was lowest at Durbin Creek, the site farthest from the ocean. Snook, redfish and even tarpon to name a few, have been seen in lakes along the St. Johns. "You can catch redfish there. It rises in the St. Johns Marshes near the Atlantic coast below lati tude 28°00'N., flows in a northerly direction, and empties into the sea north of St. Johns River … The St. Johns River is also linked to 14 lakes and numerous Florida springs including Blue Spring State Park, a protected manatee refuge. Increased salinity … The 13th State of the Lower St. Johns River Report finds that contamination by metals, pesticides and industrial products and chemicals is a serious concern.