Metridia gerlachei
Metridia gerlachei is a copepod found primarily in Antarctic and sub-Antarctic waters.
Description
In length, the female M. gerlachei is between about with a mean of. The male is smaller, between about and averaging in length.
Distribution
Metridia gerlachei is found primarily in Antarctic and sub-Antarctic waters, in addition to records from the southern Atlantic, Pacific, and Indian Oceans.
Ecology
Metridia gerlachei may start to reproduce during late winter or early spring and stops during mid-winter. Breeding peaks in December and January due to the abundance of phytoplankton. It has a relatively low egg production rate of about 6 eggs per day at saturated food concentrations.
Vertical distribution
During summer, most of the population is found from the surface to in depth. The population is evenly distributed throughout the water column in autumn and winter. It then becomes concentrated between in depth during spring. During the day, M. gerlachei is concentrated below. It starts to ascend to the surface when the decrease in light is maximal, reaching the surface a few hours later. The most feeding occurs at this point. The descent starts right after this, and ends when the increase in light reaches its maximum. The population is usually concentrated within of depth during this diel vertical migration.
Feeding
Metridia gerlachei is omnivorous, eating mainly phytoplankton, but also copepod eggs, Oncaea curvata, and other animal matter.