Another idea is to boost the numbers of zooplankton in ponds where amphibians breed. (sciencemag.org)
Bowhead whales are assumed to feed on pelagic and epibenthic zooplankton in late summer and fall (Finley 2001; Lowry et al. 2004; Pomerleau et al. 2011b), and on pre-ascending diapausing calanoid copepods in late winter and early spring, based on data from Disko Bay, Greenland (Heide - Jørgensen et al. 2012; Laidre et al. 2007). (link.springer.com)
Turner and Rooker then looked for these fatty acid signatures in five species of invertebrates, such as zooplankton, shrimp, and crabs, and nine species of fish. (sciencemag.org)