Is it true that whale sperm makes the ocean salty?

No, don't listen to Snooki...

Whale Sperm is injected directly into the female, so even if it was made of pure 100% salt and the male somehow missed the female during mating, the amount is so small that it would make no difference as to the billions of trillions of gallons of water in the seas and oceans.

The Ocean is salty mostly due to the mineral deposits that make up the sea floor, rocks and various other factors.
No, not because of whale sperm. The sea is salty because there is more than 2% salt dissolved in sea water.

A mixture of salty substances is washed out of rocks by rivers and deposited into the sea. When rain falls on the land it gradually dissolves minerals. The dissolved salts slowly enter the river and are carried down to the sea.
The ocean is salty because of the gradual concentration of dissolved chemicals eroded from the Earth's crust and washed into the sea. Solid and gaseous ejections from volcanoes, suspended particles swept to the ocean from the land by onshore winds, and materials dissolved from sediments deposited on the ocean floor have also contributed. Salinity is increased by evaporation or by freezing of sea ice and it is decreased as a result of rainfall, runoff, or the melting of ice. The average salinity of sea water is 35 o/oo, but concentrations as high as 40 o/oo are observed in the Red Sea and the Persian Gulf. Salinities are much less than average in coastal waters, in the polar seas, and near the mouths of large rivers.

Sea water not only is much saltier than river water but it also differs in the proportion of the various salts. Sodium and chloride constitute 85 percent of the dissolved solids in sea water and account for the characteristic salty taste. Certain constituents in sea water, such as calcium, magnesium, bicarbonate, and silica, are partly taken out of solution by biological organisms, chemical precipitation, or physical-chemical reactions. In open water the chemical composition of sea water is nearly constant. Because of the stable ratiOS of the principal constituents to total salt content, the determination of one major constituent can be used to calculate sea water salinity. For minor constituents and dissolved gases the composition is variable and therefore ratiOS cannot be used to calculate salt Circulation and mixing, density and ocean currents, wind action, water temperature, solubility, and biochemical reactions are some of the factors that explain why the composition of water in the open sea is almost constant from place to place.