Sex-specific food intake in whiting Merlangius merlangus

Area of Science:

• Fisheries Science
• Marine Biology
• Ichthyology

Background:

• Sexual growth dimorphism is a key factor in fish population dynamics.
• Understanding growth differences between sexes is crucial for effective fisheries management.
• Merlangius merlangus (whiting) is an important commercial fish species in the North Sea.

Purpose of the Study:

• To examine sexual growth dimorphism in Merlangius merlangus.
• To investigate the underlying mechanisms of sex-specific growth differences in whiting.
• To compare sex-specific energy uptake and allocation patterns.

Main Methods:

• Analysis of North Sea International Bottom Trawl Survey (IBTS) data.
• Examination of diet quantity and quality in relation to sex.
• Comparison of stomach content mass, liver mass, and empty stomach proportions between sexes.
• Assessment of interannual variations in feeding and metabolic indicators.

Main Results:

• Females Merlangius merlangus achieve a higher asymptotic length (L∞) than males.
• Diet composition did not differ between sexes, but females consumed more food and had fewer empty stomachs.
• Females exhibited higher liver and empty stomach masses, suggesting different metabolic costs and energy allocation.
• Interannual variations were observed in feeding, stomach fullness, and liver mass.

Conclusions:

• Sexual dimorphism in growth is significant in Merlangius merlangus, with females growing larger.
• Differences in energy uptake and allocation, rather than diet composition, likely drive female growth advantage.
• Metabolic costs and energy allocation patterns differ between male and female whiting.
• Annual environmental factors influence feeding success and energy storage in whiting.