While lox refers to a preparation method, the question of ‘what do lox eat’ pertains to the diet of salmon. Salmon, whether living in their natural habitats or raised in aquaculture, have diverse dietary needs that change throughout their lives.
The Natural Diet of Salmon
Salmon are anadromous fish, meaning they undertake extensive migrations between freshwater and saltwater environments, and their diet adapts significantly with these transitions. Young salmon, known as fry and smolts, begin their lives in rivers and streams, where their diet consists primarily of small invertebrates. These include aquatic insects and their larvae, as well as zooplankton. They feed opportunistically on what is available in their freshwater habitats.
Upon migrating to the ocean, adult salmon shift to a more predatory diet, supporting their rapid growth in the nutrient-rich marine environment. Their oceanic diet includes a variety of smaller fish, such as herring, sand lance, and capelin. Additionally, they consume squid and various crustaceans like krill, copepods, and amphipods. The specific prey consumed by wild salmon can vary depending on the salmon species, their geographic location, and the seasonal availability of these food sources.
How Diet Influences Salmon Characteristics
A salmon’s diet determines its physical and nutritional characteristics, notably the distinctive pinkish-orange color of its flesh. This coloration comes from carotenoid pigments, specifically astaxanthin. Salmon obtain astaxanthin from the crustaceans they consume, such as krill and shrimp, which are rich in these pigments. Without these, their flesh would appear grayish or whitish.
Beyond color, the wild salmon’s diet contributes to its overall nutritional profile. These natural food sources provide essential nutrients like omega-3 fatty acids and various vitamins. While specific nutrient breakdowns can vary, the quality and variety of their wild diet generally lead to a robust nutritional composition.
The Diet of Farmed Salmon
Farmed salmon are fed a carefully formulated diet, typically presented in the form of dry pellets. These pellets are a blend of ingredients designed to meet the salmon’s nutritional requirements and promote growth. Common components include fish meal and fish oil, derived from wild-caught fish like anchovies, sardines, and mackerel. However, there is a growing trend to include a significant proportion of plant-based ingredients, such as soy, corn gluten, wheat, and rapeseed, to reduce reliance on marine resources.
Astaxanthin is often added to farmed salmon feed to achieve the desired color. Without this, farmed salmon would have pale flesh. This pigment, sourced naturally or synthetically, ensures the pink-orange hue consumers expect. The use of wild fish for fish meal and fish oil in farmed salmon diets raises sustainability concerns, as it puts pressure on wild fish stocks. The composition of farmed salmon feed can also influence their nutritional profile, impacting the balance of omega-3 and omega-6 fatty acids compared to wild salmon.