Compact archival tags for the migratory studies of marine species

A prototype compact archival tag that can sample depth, temperature as well as light intensity levels at preset intervals of time, featuring low power consumption and a streamlined shape, with a provision for easy attachment has been developed. The compact design of the tag certainly exhibit better fluid dynamics, and cause less drag than a square shaped one. The circuit board has a dimension of 38 × 9 × 8 mm, weighing approximately 1.4 g including the components except for the battery, before encapsulation. The expected operative life of the tag is not less than 4 years, making it much suitable for the external attachment on the fish. The important motive behind this design and the proposed attachment technique is to reduce the drag caused by the tag to the movement of the species, thereby preserving their normal behavior, migration routes and speeds.