Family
The novel's main characters are separated from their families due to war. Each hopes that they will be able to reunite with their families. Joana hopes that her mother, father, brother, and her cousin Lina are still alive. Florian hopes to find his sister Anni. Emilia longs for her Polish homeland and hopes that her father has somehow survived. Alfred reminisces about Heidelberg and Hannelore.
However, as the war continues on, the characters begin to doubt whether their family members are still alive. At the same time, they begin to form increasingly strong bonds with each other, not only out of necessity but also out of love and compassion. Heinz and Klaus love each other as if they were grandfather and grandson. Emilia feels protected and cared for for the first time in years due to her relationships with Florian and Joana. Those who are older and stronger take care of those who are younger and more vulnerable. And at the end of the novel, Florian and Joana form a family of their own, adopting Halinka and Klaus and having a child of their own.
In this way, Salt to the Sea emphasizes that family does not only depend on blood relations but also includes the bonds that people form to love and take care of one another. While Joana, Florian, Emilia, Klaus, and others may have lost their family members, in the end they are not alone. Rather they are loved, cared for and accompanied. In contrast, whether or not their blood relations remain alive, Alfred and Eva are ultimately alone, because they only look out for themselves.
Remembrance of History
While there are many important stories about World War II, Sepetys chose to focus on the story of the Wilhelm Gustloff, because even though it is the deadliest disaster in maritime history, most people have never heard of it. Often, stories of war focus on great battles or famous historical figures. Yet Salt to the Sea brings to life the stories of World War II’s millions of refugees. In this way, Salt to the Sea questions which elements of history are preserved and which are forgotten. Sepetys insists that it is important for us to preserve the memory of those who perished and to give a voice to the survivors of historical tragedies. Through remembrance, we can work to make sure that the tragedies of the past are not repeated.
Heroism
In Salt to the Sea, Sepetys presents different ideas of heroism and prompts the reader to question what true heroism looks like.
Alfred's concept of heroism is hateful. He believes a hero is someone superior who feels no sympathy for the weak. For example, at the end of the novel, he believes that he will finally be a hero and serve Germany by killing Emilia for being Polish. Alfred's concept of heroism is also rooted in selfishness. For example, he only helps Florian because he believes it will lead him to receive a medal of honor and be seen as heroic.
In contrast, other characters in Salt to the Sea help, and even save, others through small, selfless acts of kindness. For example, Joana saves Emilia and Florian by providing them with medical attention, even though doing so puts her own life at risk. When the Gustloff is sinking, Emilia saves Klaus by sending him to the lifeboat rather than getting into it herself. The characters do not perform these acts hoping for recognition or medals. Rather, they do so out of a genuine desire to help those around them. While such acts of selfless kindness are not usually celebrated in history books or movies, Sepetys represents them as true heroism.
Revenge
Florian steals the key and map to the Amber Room to take revenge on Dr. Lange. He wants to take revenge on Lange for lying to him and using him. Lange told Florian that he was brilliant and that he would help to preserve the artistic treasures of Europe. But in reality, Lange was using Florian to help him steal some of Europe's most prized artworks. Moreover, Florian viewed Lange as a mentor figure and wrote him many personal letters. However, one day he discovered that Lange never read the letters.
Florian steals Hitler's favorite piece from the Amber Room, the amber swan, to take revenge on Hitler. He wants to take revenge on Hitler not only for stealing so much treasured art but also for leading to his father's assassination and his family's separation.
However, by the end of Salt to the Sea, Florian realizes that he is caught in a vicious cycle of revenge. He realizes that all of his lying and killing was in vain. In part, this is because he believes that both he and the amber swan will end up at the bottom of the Baltic Sea as the Wilhelm Gustloff sinks. Moreover, he realizes that responding to lies with more lies isn't good for anyone and only creates more pain. In the end, Florian reflects that revenge is a useless cycle, since it tries to answer pain by inflicting more pain. Through Florian’s character, Sepetys brings the theme of revenge to the fore.
Secrecy
Secrecy is an important theme in Salt to the Sea. Each of the four narrators and main characters has a secret. Emilia's secret is that she is pregnant, and that this pregnancy is the result of her having been raped by Russian soldiers. Florian's secret is his theft of the amber swan. Joana's secret is that she is a murderer because she feels responsible for her cousin Lina and her family being sent to a labor camp in Siberia. And Alfred's secret is that despite his allegiance to the Nazi regime, he is in love with a half-Jewish woman.
As the novel progresses, the characters gradually reveal their secrets. Sometimes, the characters reveal their secrets in a way that may be considered manipulative, because they need something from another character. For example, Florian tells Joana his name and opens up to her about his family because he wants her to write him a medical testimony.
However, at other times, the characters let their guards down and share their secrets because they feel a genuine emotional connection. Sometimes, revealing a secret is like a confession, meant to lighten the burden that a character carries. For example, when Emilia reveals to Joana that her pregnancy is the result of a rape, she does so because she wants to clear her conscience and free her soul.
Trauma
After four years of war, many of the novel's characters are traumatized. This means that they experience the lasting emotional and psychological damage of the terrible events they have experienced. In Salt to the Sea, Sepetys indicates that while the physical impacts of war are horrible and may change peoples' lives forever, it is often war's psychological consequences that are the most permanent and difficult to deal with. Each narrator sees their emotional state as a hunter that pursues them from the beginning to the end of the novel. While they may be able to recover from the physical hardships they face and the wounds they suffer, even those who survive the sinking of the Wilhelm Gustloff will have to contend with their trauma for the rest of their lives. This is reflected in Florian's statement twenty years later, at the end of the novel. He says that his fear and terror have retreated but that they never disappear entirely.
Race and ethnicity
The Nazis persecuted many people on the basis of their ethnic identity, national origin, religious and political beliefs, and lifestyle choices.
Nazi Germany was determined to expand its territory and take the resources of other nations. The Nazis justified this violence through the false belief that the Germans formed part of an Aryan "master race," which they viewed as superior to other races. For this reason, they discriminated against many different types of people, including those that Alfred lists in his song: "Communists, Czechoslovaks, Greeks, Gypsies, Handicapped, Homosexuals, Jews, Mentally ill, Negroes, Poles, Prostitutes, Russians, Serbs, Socialists, Spanish Republicans, Trade Unionists, Ukrainians and Yugoslavs."
Thus, in Salt to the Sea, each character’s fate is influenced by their identity. For example, Emilia is seen as subhuman and she is persecuted for being Polish. Joana is Lithuanian but she is able to repatriate to Germany because her mother has German roots. Meanwhile, as an East Prussian, Florian is expected to fight in the Wehrmacht, the German Armed Forces. Alfred, on the other hand, is German and according to the Nazis belongs to a “master race.”
