With increasing interest in human health, stretchable and wearable sensors have attracted a lot of attention for real-time health monitoring. However, most wearable sensors require external power sources, show structural failures under repeated mechanical strains and are not suitable for sensing low-frequency body motion. Herein, we report that a highly stretchable and self-healable hydrogel conductor was newly synthesized with all ocean biomaterials including catechol, chitosan and diatom. The catechol-chitosan-diatom hydrogel (CCDHG) conductor was exploited as stretchable triboelectric nanogenerators (TENG) for energy harvesting from human motion and skin-attachable self-powered tremor sensors for monitoring the health condition of Parkinson?s disease (PD) patients. The catechol-chitosan-diatom hydrogel triboelectric nanogenerator (CCDHG-TENG) showed open-circuit voltage of 110 V, short-circuit current of 3.8 ?A, and instantaneous power density of 29.8 mW/m2. Furthermore, a self-powered tremor sensor, which was specially designed with an M-shaped Kapton film and the CCDHG-TENG, was applied to identify the health conditions of PD patients using a machine learning algorithm. This study provides a new strategy to design stretchable TENGs with all ocean bio-materials and this can be utilized for various applications, including stretchable power sources, wearable electronics and health monitoring systems with artificial intelligence.