Field deployments occurred in November 2021 and May 2023 near Faial and Pico Islands, Azores archipelago (38.3003° N, 28.3522°W). Data were collect during day boat trips (21 foot center console RIB) when winds were below 15 knots. Animals were caught at depths of around 250 meters, and were tagged by PI and Chief Scientist Aran Mooney.
Care was taken during capture and handling of animals to limit physical stress. Squid were caught by jigging, which is a minimally invasive means of capture since it reduces damage to the fragile epi- dermal layer. Once at the surface, animals were transferred to a padded table equipped with constant seawater flow to ventilate the gills. Only large squid with DMLs greater than 45 cm were selected for tagging. Squid eyes were covered during tagging to reduce light and visual stress. Tagged squid were immediately released over their capture site within 6−11 min.
The ITag contains a triaxial inertial measurement unit (IMU) with an accelerometer, gyroscope, and magnetometer sampled at 100 Hz (TDK Invensense MPU9250), and pressure, temperature (Keller 7LD), and light sensors (Intersil ISL29125) sampled at 1 Hz.