Entry of Immature Cuttlefish <i>Sepia esculenta</i> into Basket Traps

Abstract

In the present study, trapping experiments and observations on the behavior of immature cuttlefish Sepia esculenta towards the traps were made under field and laboratory conditions. Trapping experi ments clearly demonstrated the entry of immature cuttlefish into the basket traps. The entry rate was sig nificantly higher in immature than in mature cuttlefish studied in the same laboratory conditions. When entering and leaving the trap, cuttlefish swam straight primarily with arms in front, thus suggesting their active movement.After entry, cuttlefish remained stationary at the bottom. Females stayed in the trap longer than 3 days, while males left within 3 days. The existence or the position of branches did not influence the entry of cuttlefish into the traps. These results may rule out the possibility that spawning is a motivation for the entry of cuttlefish into the traps.

Cuttlefish spawning and visually mediated entry into basket traps

“…Similar behavior was observed among males and immature cuttlefish entering traps. 15 The body position taken by the cuttlefish when entering the trap allows for sudden escape from the trap. The fastest movement is achieved in the direction of jet propulsion when the funnel is parallel to the body axis.…”

Why do cuttlefish Sepia esculenta enter basket traps? Space occupation habit hypothesis

“…Cuttlefish reaction to variation in the quantity of the visual stimulus of a basket trap was tested in cylindrical traps (90 cm diameter and 45 cm height) 5 of black, gray and white placed inside tanks of white or black interior. In order to produce a water tank with black interior, a black vinyl sheet (0.33 mm thick) was used to cover the walls.…”

“…Using the foldable basket trap (105 cm diameter and 50 cm height) 5 as the model fishing gear, the following visual targets were made of different mixtures of components for testing ( Fig. 2).…”