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Abstract. The shallow-water hydrothermal vents (SVs) located off Kueishan (KS) Island, Taiwan, are one of the world's most intensively studied vent systems. It has long been known that white vents (WVs) and yellow vents (YVs) differ in the color and composition of the vent plumes. The endemic vent crabs (Xenograpsus testudinatus) are abundant in both vent types, and ovigerous females migrate to the vent periphery with a distance of 100–200 m to release their offspring. However, most research on the vent crabs was associated with WV or unspecified vent areas. To increase our knowledge of the crabs dwelling in other vent types, we compared the feeding habits of the vent crabs living in WV and YV with 2 sampling months. Specifically, we examined the benthic community of WV and YV, the isotopic niche width, and protein expression patterns of the crabs from the two vents at a distance of 100 m and sampled in July and August 2010. The coverage of sessile organisms and low-mobility fauna in WV was more abundant than in YV, based on the survey in August 2010. The δ13C and δ15N values of crabs differed spatially and temporally (multivariate analysis of variance test; p<0.05). The niche width of the vent crabs from YV-August (0.88 ‰2) narrowed substantially compared to the rest, i.e., YV-July (2.94 ‰2), WV-July (2.88 ‰2), and WV-August (3.62 ‰2; p<0.05), respectively. Based on the protein expression patterns, the vent crabs exhibited three groups, i.e., WV-July and YV-July, WV-August, and YV-August, respectively. Our results indicated that the dwelling crabs were associated with their living vent, and within-vent variability was more noticeable in YV compared to WV. We suggested that vent crabs inhabit their resident vent. Even at a scale of meters, trans-vent movement is probably rare as an adaptation to minimize predation risk.

This paper presents data on carbon and nitrogen stable isotopes in benthos from shallow-water hydrothermal vents (SV) and nearby non-vent rocky reefs (NV) located in northeastern Taiwan, which is related to the article “Isotopic niche differentiation in benthic consumers from shallow-water hydrothermal vents and nearby non-vent rocky reefs in northeastern Taiwan” [1] . Field sampling work was conducted in July 2009 and July–August 2010 to collect sediment organic matters (SOM), zooplankton, and benthos for carbon and nitrogen stable isotopic analyses. Scuba divers collected macrobenthos, seawater, and surface sediments (0–2 cm). The collection of zooplankton was by a North Pacific standard net and trawled vertically. Testing samples were lyophilized before grounding by a mortar and pestle. For carbon and nitrogen isotope analyses, approximately 1 mg of powder was weighed and encapsulated in a tin capsule. Analyses were performed at the stable isotope laboratory at the University of California at Davis using an Integra Mass Spectrometer elemental analyzer (PDZ Europa, Sandbach, UK). The information is presented as 187 and 53 unprocessed data points from SV and NV, which incorporates δ 13 C and δ 15 N values (‰) of sediment, zooplankton, and benthos’ tissue samples. Data from SOM provides information about chemosynthetic activity in SV sites. These data can be used to correlate food sources of consumers inhabiting shallow-water hydrothermal vent and rocky reef ecosystems in subtropical regions.

Abstract. The shallow-water hydrothermal vents (SVs) located off Kueishan (KS) Islet, Taiwan, are one of the most intensively studied vent systems. Here, two distinct vent types were identified as white vents (WVs) and yellow vents (YVs), based on the color, physical and chemical characteristics of vent plumes. The endemic vent crabs (Xenograpsus testudinatus) are abundant in both WVs and YVs. However, most research on the vent crabs was associated with WV or unspecified vent areas. Studies on crabs dwelling in other vent types are rare. Here, we investigated the feeding habit of crabs inhabiting YV and made a comparison with WV crabs. Specifically, we examined the benthic community of WV and YV, isotopic niche width, and protein expression patterns of the crabs from the two vent types at a distance of 100 m. The coverage of sessile organisms and low-mobility fauna in WV were more abundant than in YV. The δ13C and δ15N values were insignificantly different between crabs from WV and YV. The niche width of crabs from WV was significantly broader than those from YV, shown as SEAc areas of 3.62 ‰2 vs. 0.88 ‰2 (p < 0.05). The overlap percentages in WV and YV were 23.9 % and 97.9 %, respectively. The food sources of crabs in WV were more diverse than those in YV. Based on the protein expression patterns, the vent crabs were classified into WV- and YV-dwellings. Our results revealed that the feeding habits of the endemic vent crabs (X. testudinatus) are adapted to their vent types at a distance of 100 m, and the trans-vent movement is uncommon.