Meeting Abstract

P1.16  Friday, Jan. 4  Substrate preference of the Pacific sand lance, Ammodytes hexapterus PETERSON, A.N.*; SUMMERS, A.P.; BIZZARRO, J.J.; University of Washington; Friday Harbor Labs anpetey@gmail.com

Commercial fish stock populations can be linked to the health of forage fish populations. The Pacific sand lance, Ammodytes hexapterus, is an essential link between zooplankton and higher trophic levels such as birds, marine mammals, and fishes. As a burrowing fish, understanding the behavior and habitat is key to ensuring the long-term sustainability of sand lance populations. Sand lance spend most of their time either schooling in the water column or buried beneath the substrate. We performed paired preference trials during daylight hours to compare burrowing tendencies between sediment sizes. Sediments were collected on San Juan Island and sorted using a RoTap sediment analyzer. The grain sizes chosen for the trial were medium sand (0.25 – 0.5 mm), coarse sand (0.5 – 1.0 mm), very coarse sand (1.0 – 2.0 mm), and very fine gravel (2.0 – 4.0 mm). The study was conducted on sub adults (8.5-11.5cm TL) to account for any ontogenetic variability in burrowing behavior. We found that sand lance could burrow into all of the provided substrates, but they prefer coarse sand. Observations have shown that Pacific sand lance spend the majority of the night buried under the sediment. We also conducted nocturnal preference experiments during night time hours (23:00 – 03:00). At night, A. hexapterus displayed no preference between coarse sand and very coarse sand, but did prefer coarse sand over medium sand. Apparently at night, when visual clues are eliminated, the preference for substrate type is relaxed. However, preference is also being evaluated by other sensory systems as there is still a notable distinction in the proportion of buried sand lance between substrates.