Laboratory estimates of the daily ration of the Norway lobster Nephrops norvegicus from the southern coast of Portugal

Daily ration and preference for different types of food were studied in Nephrops norvegicus by means of simple laboratory experiments. Lobsters were collected off the south coast of Portugal at depths of 600 m in 1997 and were held in captivity individually for a period of several weeks at 14 degrees C of water temperature in a closed circuit of sea water with a salinity of 37 parts per thousand, for adaptation. Two groups of 10 lobsters were fed three different types of food alternate: a. Fish - Engraulis encrassicolus; b. Polychaeta - Diopatra neapolitana or Marphisa sanguinea; c. Crustacea - Palaemonetes varians. Daily ration was estimated at 0.0077 g dried weight (DW) per g body weight per day, for the group fed every 24 h, and 0.0087 g DW per g body weight per day for the second group, fed every 48 h. These can therefore be considered as maximum values for food intake per day. Considering the amount of food ingested daily as a measure of preference of different types of food, we can also conclude that Norway lobsters prefer crustaceans to fish, and these again to polychaetes.