Meeting Abstract

P3.47  Thursday, Jan. 6  Burrowing Preference and Capability in the Pacific Sand Lance BALABAN, JP*; BIZZARO, JJ; SUMMERS, AP; University of Rhode Island; University of Washington; University of Washington jbalaban@my.uri.edu

The pacific sand lance, Ammodytes hexapterus, is a schooling species of fish in the Pacific Northwest, and is a major prey item for shore birds, large fish and mammals. Sand lances exhibit an unusual burrowing behavior in which they appear to swim into sandy substrates. They burrow to escape predators as well as to hibernate in the sand during the winter months. These fish are found in intertidal and subtidal zones, but primarily over sediment with coarse grains of sand (mostly between 0.36 mm and 1.0 mm). We conducted a series of behavioral experiments to determine whether sand lances prefer to burrow into certain sized sediments by giving them the option of a fine sediment (0.25 mm to 0.52 mm), a small coarse sediment (0.52 mm to 1.0 mm) and a larger coarse sediment (2.0 mm to 4.0 mm). We also determined whether sand lance could tell the difference between compacted and uncompacted sediment. We determined that sand lances prefer to burrow into sediment with 0.52 mm to 1.0 mm grains. We also explored whether there was a difference in the force needed to burrow in different sediments using a resin model of a sand lance attached to a force gauge and thrust into different sediments to determine the force required to burrow. As expected, compacted sediment requires more force to burrow into than uncompacted sediment. Interestingly, it does not require less force for sand lances to burrow into the behaviorally preferred sediment size, and in some cases this sediment actually requires more force for penetration. Although sand lances prefer to burrow into a narrow size range of sediment, other factors yet to be determined must contribute to this choice other than ease of penetration.