Stomach content of 4, age-0 fish species from the Greenland Sea, August-September 2017

Age-0 fish were collected in the Greenland Sea from 22 August to 12 September 2017, onboard RV Dana, using a Methot Isaac Kidd net (MIK net), a 2 m-diameter frame carrying a 1500 µm mesh black net. Onboard, age-0 fish (larvae and juveniles) were sorted from the macrozooplankton sample, identified to the lowest taxonomic level possible, measured fresh (standard length, SL), and preserved in 95% ethanol. The diets of age-0 A. glacialis, B. saida, L. fabricii and T. nybelini were estimated from the gut contents of 8-25 individuals per species, selected to represent the size range and spatial distribution of the collection. The digestive tracts were dissected in glycerol and individual prey were identified to the lowest taxonomic level possible. The most abundant prey categories were used in diet description and selectivity index calculations: copepod nauplii, copepodite stages of Triconia borealis, Oithona similis, Microcalanus spp., Pseudocalanus spp., and Calanus spp.

2017年8月22日至9月12日，研究人员搭乘达纳号（RV Dana）科考船于格陵兰海采集0龄鱼类，所用采样设备为梅特-艾萨克·基德网（Methot Isaac Kidd net，简称MIK网），该网配有直径2米的框架与1500微米孔径的黑色网衣。在科考船上，研究人员从大型浮游动物样本中分拣出0龄鱼（仔鱼与稚鱼），将其鉴定至尽可能低的分类阶元，活体测量其标准体长（standard length，SL），并以95%乙醇进行固定保存。针对A. glacialis、B. saida、L. fabricii及T. nybelini四个物种的0龄个体，研究人员通过每个物种8至25个个体的肠道内容物评估其食性，所选个体需覆盖本次采集样本的体长范围与空间分布格局。随后研究人员在甘油中解剖这些个体的消化道，将单个猎物鉴定至尽可能低的分类阶元；食性描述与选择性指数计算采用丰度最高的猎物类群，包括桡足类无节幼体、北极大三角剑水蚤（Triconia borealis）、相似大眼剑水蚤（Oithona similis）、小哲水蚤属（Microcalanus spp.）、拟哲水蚤属（Pseudocalanus spp.）以及哲水蚤属（Calanus spp.）