North Atlantic Whiting: Dietary Habits and Feeding Ecology

The North Atlantic whiting (Merlangius merlangus), a member of the cod family (Gadidae), is a commercially important fish species found throughout European waters. Understanding its dietary preferences and feeding behavior is crucial for comprehending its role in the marine ecosystem.

Ontogenetic Shifts in Diet

The diet of whiting changes considerably as they grow and develop. These ontogenetic shifts reflect the availability of prey and the increasing size and predatory capabilities of the fish.

Larval Stage

Newly hatched whiting larvae are planktonic and primarily consume small zooplankton, including copepod nauplii and other microscopic organisms. This initial feeding stage is critical for survival and growth.

Juvenile Stage

As juveniles, whiting begin to transition to a more varied diet. They feed on larger zooplankton, such as copepods, amphipods, and small crustaceans. Small fish larvae may also be included in their diet at this stage.

Adult Stage

Adult whiting are primarily piscivorous, meaning their diet consists largely of other fish. The specific fish species consumed vary depending on location and prey availability. Common prey items include:

• Sand eels (Ammodytes spp.)
• Sprat (Sprattus sprattus)
• Herring (Clupea harengus)
• Young cod (Gadus morhua)
• Other small gadoids
• Crustaceans (e.g., shrimp, crabs) are also consumed, but to a lesser extent compared to fish.

Feeding Behavior and Ecology

Whiting are active predators that typically hunt in midwater. They are known to exhibit opportunistic feeding behavior, taking advantage of available prey resources. Factors influencing prey selection include:

• Prey Abundance: The availability of different prey species in the environment directly influences the composition of the diet.
• Prey Size: Whiting tend to select prey that are appropriately sized for their mouth and digestive capabilities.
• Prey Behavior: The swimming speed and escape tactics of prey species can affect their vulnerability to predation.
• Habitat: Whiting are found in a variety of habitats, from shallow coastal waters to deeper offshore areas. The specific habitat influences the types of prey that are accessible.

Impact on the Ecosystem

As a significant predator, whiting play a crucial role in structuring marine food webs. Their consumption of smaller fish and crustaceans helps to regulate populations and maintain balance within the ecosystem. Changes in whiting abundance can therefore have cascading effects on other trophic levels.