Description: Males of the four crab species Percnon affine (H. Milne Edwards, 1853), Grapsus albolineatus (Latreille in Milbert, 1812), Orisarma intermedium (Schubart &Ng, 2020), and Geothelphusa albogilva (Shy, Ng & Yu, 1994), were collected in the southern part of Taiwan in May 2007. Individuals were starved for 12 days and midgut glands were dissected before and after the starvation period. Midgut glands were lyophilized and total lipids were extracted with dichloromethane:methanol (2:1 per volume) and an aqueous solution of 0.88% KCl. Extracted lipid mass was determined gravimetrically. Lipid classes were separated and quantified using Thin-Layer Chromatography with an integrated flame ionization detector (MK-5 TLC/FID analyzer, Iatron Laboratories). Lipids were converted to fatty acids methyl esters (FAME) by applying methanol containing 3% concentrated sulfuric acid. FAMEs were quantified by gas chromatography equipped with a DB-FFAP column, a programmable temperature vaporizer injector, and a flame ionization detector. Helium was used as carrier gas. Fatty acids were identified by retention times and by using fish oil standard (Marinol). Data are supplement to: Stumpp et al (2021) Dietary preferences of brachyuran crabs from Taiwan for marine or terrestrial food sources: evidence based on fatty acid trophic markers accepted for publication in Frontiers in Zoology

Description: Highlights: • Environmental conditions cause specific zooplankton life strategies. • No ontogenetic or diel vertical migration in the life cycle of Calanus chilensis. • Spatial expansion of Calanus chilensis secondary production far offshore. • Compacted surface biomass of Calanus chilensis allows easy foraging by anchovy. Abstract: Calanid copepods of the genera Calanus and Calanoides are key components of zooplankton communities in upwelling systems. Here, we compare the life-history traits of Calanus chilensis from the Humboldt Current Systems (HCS) off northern Peru and its counterpart Calanoides natalis from the northern Benguela Current System (BCS) off Namibia. A comprehensive data set of the distribution and abundance patterns of these species along extensive horizontal and vertical scales is presented. C. chilensis from the HCS was almost exclusively restricted to the surface layer (50–0 m) above the oxygen minimum zone (OMZ), whereas C. natalis from the BCS inhabited the entire water column down to 800 m performing ontogenetic vertical migration (OVM) through the OMZ. Resting stages of C. natalis at depth accumulated high amounts of lipid (30–60% of dry mass, DM), whereas C. chilensis did not rely on lipid reserves. These findings confirm that the life cycle of C. chilensis does not include OVM with diapause at depth. Surprisingly, the regional distribution of C. chilensis secondary production extended much further offshore (〉200 km from the coast) than is typical of other coastal upwelling systems. Deviating environmental conditions forced the two key calanid species to develop specific, but different life strategies for HCS and BCS. Compacted biomass concentrations of C. chilensis in the surface layer from the shelf (≤3 g DM m−2) to offshore waters (≤1.5 g DM m−2) facilitate easy and efficient foraging by predators such as juvenile Peruvian anchovies. In contrast, a large fraction of the C. natalis biomass occurs within the OMZ and is thus out of reach for hypoxia-sensitive predators. Calanoid copepods (e.g. C. chilensis) play a crucial role as important prey for growth and recruitment of small pelagic fish. Thus, the compacted biomass and high productivity of C. chilensis at the surface derived from its adaptive life-history traits (no OVM) may explain the superior trophic transfer efficiency and hence enormous fisheries yield of the HCS compared to the BCS.