It's an early October morning and temperatures are just above freezing when Christoph Oberle and his assistants haul a big dragnet full of carp across a pond to the shore in Kosbach, near the southern German city of Erlangen. It's harvest time for carp — a traditional Christmas meal in many parts of Europe.

The men — Oberle's friends and relatives — start their day with breakfast together before donning their waders and walking into the artificial pond's cold water. The level had been lowered in the days before to group the fish being raised there closer together. It takes fewer than 30 minutes to corral them close enough to the bank to start using hand nets to scoop them into big tubs and then pour them on a ramp to sort before putting them into smaller basins by type.

In addition to carp, Oberle raises zander and perch, starting them in the spring and letting them grow through the summer. After three hours of hard work about three tons of fish — less than expected — are swimming in the smaller basins to be distributed to customers, and eventually make their way to people's plates.

For Oberle, his work is a longtime family tradition. One of his ancestors bought a farm with 1.2 acres of ponds in 1650. More than 360 years later he owns 40 ponds and offers carp at his own restaurant, sells it smoked in a fish shop and provides it to fishing clubs to stock their own waters.