Meeting Abstract
P3.67 Sunday, Jan. 6 Moon Phase and Nutrient effects upon Diel Vertical Migration Patterns of Zooplankton and Myctophids in the North East Pacific TRINH, R*; DEL GIZZI, A; HATFIELD, I; UC Berkeley fish.r.awsome@gmail.com
Diel vertical migration (DVM) is understood to be a circadian rhythm in which the light-dark cycle of day and night are key exogenous factors, but little is known about how available moon light impacts this behavior. To further understand DVM patterns exhibited by myctophids, small pelagic fish of both environmental and economic importance, moon phase percent was taken into account and compared to myctophid bio-density found throughout the water column at night, in order to assess the impact moon light alone has on DVM. Bio-density of myctophids was obtained by counting the number of myctophids found in net tows deployed nightly between the times of 2300 and 0000 along the cruise track, at three different depths: a neuston-net (.25 m), and two meter-nets (50-100 m and 200-300 m) from which myctophids were collected and identified from each tow. To account for variations in myctophid bio-density not explained by changes in moon phase percent, zooplankton biodensity (ml/m3), nutrients (µM) in surface waters, varying latitudes (degrees) and water masses traveled through, and genera of myctophid found were all investigated to determine corresponding relationships regarding DVM. It was found that zooplankton bio-density and myctophid bio-density were inversely correlated, indicating a predatory relationship, as expected and that as moon phase increased, myctophid bio-density decreased in each net, also as expected since many organisms that undergo DVM, do so to remain hidden from well lit, shallow waters. Further analysis and research on myctophids in the North Easter Pacific Ocean and their DVM is still required but this study hopes to shed some light on myctophids’ dynamic DVM patterns in order to better understand moon light’s effects on DVM as a whole, and to understand their distribution and behaviors in the world’s oceans.
