The accumulation of storage lipids is an important life history trait and a key function in the energy metabolism of crustaceans. The common storage lipid in species from temperate regions is the neutral lipid triacylglycerol (TAG). It is synthesized through the Kennedy pathway by the enzyme diacylglycerol acyltransferase (DGAT). This enzyme is ubiquitous in eukaryotic species and is expressed as two evolutionary separated forms, DGAT1 and DGAT2. The caridean shrimps Crangon crangon and Pandalus montagui share a similar habitat but follow different metabolic strategies. Previous studies showed significantly lower total lipid (TL) levels in the midgut gland of C. crangon compared to P. montagui. While TAGs are frequent in P. montagui, phospholipids are the prominent lipid class in C. crangon. It is hypothesized that the reason for this difference in lipid class composition are mutated DGAT enzymes in C. crangon, which impair the synthesis of TAGs in the midgut gland. Therefore, the enzyme was studied by nucleotide and amino acid sequence analysis from transcriptome data and enzyme activity measurements. Both species possess transcripts encoding for DGAT1 and DGAT2. In C. crangon, a mutation in one DGAT1 isoform as well as a mutated cysteine residue in DGAT2 was found. These mutations are capable of impairing enzyme functionality. Using a fluorescent labeled substrate, DGAT activity was shown in both species. However, the DGAT activity of C. crangon was lower than that of P. montagui. Furthermore, C. crangon exhibits higher DGAT activity in spring than in summer, which indicates a seasonal variation of DGAT expression. The metabo-lic traits of C. crangon and P. montagui were also discussed in respect to their reproductive strategies, food spectrum, and their distributional range. This study showed that the TAG synthesis of C. crangon is reduced, which, at least partly, is due amino acid point mutations in the DGAT enzyme. As a consequence, C. crangon is unable to accumulate high amounts of storage lipids and must rely on continuous food supply. Probably, the inability of lipid storage also influenced the reproduction strategy of C. crangon towards a continuous long lasting reproduction period. Nevertheless, future studies are required to investigate the expression of DGAT mRNA, the substrate specificity of the DGAT isoforms, and the apparent seasonal pattern of DGAT activity and TAG synthesis.