The California Sea Lion - The Fin Foundation
California sea lions can also live in fresh water for periods of time. . to 17 percent of listed adult salmonids 'meet[s] or exceed[s] the objectives of doing no harm. Iliamna Lake, home to the United States' only population of freshwater seals, describe the seals as fatter, larger and darker in color than saltwater seals, with a . Where the fresh and salt waters meet aux Coudres, as the tides start to be felt and fresh water mixes with salt water from the Atlantic Ocean. This is without counting the various seal and anadromous fish species that can live in both fresh .
Freshwater fish, small invertebrates and plant life would also be affected; without any available prey, Iliamna Lake seals would starve. Climate change will also affect salmon and result in increased water runoff, warmer water temperatures, greater water flows and increased siltation in the streams and rivers in which salmon spawn and lay their eggs.
Young salmon fry and salmon eggs may be washed downstream before maturing, while conditions suitable for salmon spawning may cease to exist. Climate change will also decrease the quality of Iliamna Lake seals' habitat. A rise in water level during the summer may cover up important dry-land haul-out sites for seals; changes in ice thickness and timing of ice cover may hurt their winter habitat.
Climate change could also affect the timing of salmon runs, so that Iliamna Lake seals have little food during the most energetically demanding moments in their life cycle. Seals of the World ] Habitat True seals typically live in the cold ocean waters of the Arctic or off the coasts of Antarctica.
Some seals make caves in the snow to live in. Harp, ringed, hooded, spotted, bearded and ribbon seals live in the Arctic. Crabeater, Weddell, leopard and Ross seals live in the Antarctic. They can spend about two years in the open ocean before returning to their breeding grounds, according to the NOAA. Diet Seals generally prey on fish, but they will also eat eel, squid, octopus and lobster.
Leopard seals will eat penguins and smaller seals, according to Seals World. The gray seal can eat 10 pounds 4. They sometimes skip eating for a few days, and often stop eating completely during mating season and will live off energy from their stored-up blubber for weeks.
The seal pup and Ursula, the mother. The baby is the first born at the New England Aquarium in Boston, which is trying to breed the vulnerable animals. New England Aquarium Baby seals When mating season comes, male seals will issue deep, throaty calls to attract the attention of females.
Where the fresh and salt waters meet | Musée du Bas-Saint-Laurent
A male seal will also call out to let other males know that his females are spoken for. Males are very territorial when it comes to mating.
They will fight for the right to mate, hitting and biting each other. Accompanying these strong salinity and density gradients are large vertical changes in current direction and strength.
Pliny the Elder, the noted Roman naturalist, senator, and commander of the Imperial Fleet in the 1st century A. But when the velocity difference reaches a certain threshold, vigorous turbulence results, and the salt and fresh water are mixed. Tidal currents, which act independently of estuarine circulation, also add to the turbulence, mixing the salt and fresh waters to produce brackish water in the estuary. In the Fraser River, this circulation is confined to a very short and energetic frontal zone near the mouth, sometimes only several hundred meters long.
In other estuaries, such as San Francisco Bay, the Chesapeake Bay, or the Hudson River, the salt front and accompanying estuarine circulation extend inland for many miles. The landward intrusion of salt is carefully monitored by engineers because of the potential consequences to water supplies if the salt intrusion extends too far.
The California Sea Lion
For instance, the city of Poughkeepsie, N. Roughly once per decade, drought conditions cause the salt intrusion to approach the Poughkeepsie freshwater intake. The last time this happened, inextra water had to be spilled from dams upstream to keep the salt front from becoming a public health hazard.
The lifeblood of estuaries Estuarine circulation serves a valuable, ecological function.
The continual bottom flow provides an effective ventilation system, drawing in new oceanic water and expelling brackish water. This circulation system leads to incredible ecological productivity. Nutrients and dissolved oxygen are continually resupplied from the ocean, and wastes are expelled in the surface waters. This teeming population of plankton provides a base for diverse and valuable food webs, fueling the growth of some of our most prized fish, birds, and mammals—salmon, striped bass, great blue heron, bald eagles, seals, and otters, to name a few.
Where the Rivers Meet the Sea
The vigor of the circulation depends in part on the supply of river water to push the salt water back. The San Francisco Bay area has become a center of controversy in recent years because there are many interests competing for the fresh water flowing into the Bay—principally agriculture and urban water supplies extending to Southern California. Estuarine circulation is also affected by the tides; stronger tides generally enhance the exchange and improve the ecological function of the system.
The Hudson estuary, for example, is tidal for miles inland to Troy, N. Some are self-inflicted; some are caused by the abuses of human habitation. An estuary, with all of its dynamic stirrings, has one attribute that promotes its own destruction: When suspended mud and solids from a river enter the estuary, they encounter the salt front.
Unlike fresh water, which rides up and over the saline layer, the sediment falls out of the surface layer into the denser, saltier layer of water moving into the estuary.
As it drops, it gets trapped and accumulates on the bottom.
Slowly, the estuary grows muddier and muddier, shallower and shallower.