Tank Respirometry Was Used To Study The Interactive Effects Of Protein: Lipid Level (55%:11% Vs. 42%:16%; Both Diets Isoenergetic) And Temperature (11, 6 And 2 Degrees C) On The Magnitude And Duration Of Specific Dynamic Action (sda) In Juvenile Atlantic Cod And Haddock. The Protein: Lipid Level Did Not Affect Any Measured Variable. However, Numerous Temperature And Species Effects Were Observed. For Example, Although The Maximum Post-feeding Oxygen Consumption (30-50% Above Routine Metabolic Rate; Rmr) And Sda Duration (similar To 55-85 H; Sda(dur)) Were Not Affected By Temperature, Sda(dur) G(-1) Of Food Increased From 11 To 2 Degrees C (from Similar To 3 To 12 Hg Food(-1)). While Absolute Sda (mg O-2) Decreased By Similar To 60-65% In Cod And Similar To 75% In Haddock From 11 To 2 Degrees C, Due To A Concomitant Decrease In Food Consumption From Similar To 2.0% To 0.6% Body Mass, Sda Comprised Between 3.3% And 5.2% Of The Dietary Energy Content At All Temperatures. Finally, Rmr At 11 And 2 Degrees C And Sda(dur) At 2 Degrees C Were 25-35% And 25% Greater In Cod, Respectively, As Compared With Haddock. These Results Suggest That Feeding Reduced Protein Diets At Low Water Temperatures Is Unlikely To Improve The Growth Of These Species.