Mother-Calf Separation Research

Conservation Physiology investigates the role(s) that physiological responses to human activities mbabymother17.jpgay play in population dynamics of natural populations. The Conservation Physiology group at the SWFSC is investigating physiologically-based factors that may be leading to separation of dolphin mothers and calves during attempted evasion of tuna purse-seine sets, and to subsequent mortality of calves if the separation is permanent. The possibility that calf separation and subsequent mortality may be an important factor contributing to the lack of recovery of dolphin populations in the ETP, despite very low observed mortality of adults, is suggested by the observation that 75-95% of lactating females found dead in the tuna purse-seines are not accompanied by a nursing calf (Archer et al. 2004). The mother-calf separation studies comprise a series of studies examining various aspects of dolphin mother-calf associations from a physiological perspective.

Selected Publications:

Noren, S.R. and E.F. Edwards. 2007. Physiological and behavioral development of delphinid calves: implications for calf separation and mortality due to tuna purse-seine sets. Marine Mammal Science 23(1):15-29.

Noren, S.R., G. Biedenbach and E.F. Edwards. 2006. Ontogeny of swim performance and mechanics in bottlenose dolphins (Tursiops truncatus). Journal of Experimental Biology 209: 4724-4731.

Edwards, E.F. 2006. Duration of unassisted swimming activity for spotted dolphin (Stenella attenuata) calves: implications for mother-calf separation during tuna purse-seine sets. Fishery Bulletin 104:125-135.

Weihs, D. 2004. Hydrodynamics of Dolphin Drafting. Journal of Biology 3:1-23.

Edwards, E. F. 2002a. Behavioral contributions to separation and subsequent mortality of dolphin calves chased by tuna purse-seiners in the eastern tropical Pacific Ocean. NMFS Southwest Fisheries Science Center Administrative Report LJ-02-28. 33 p.

Edwards, E. F. 2002b. Energetics consequences of chase by tuna purse-seiners for spotted dolphins (Stenella attenuata) in the eastern tropical Pacific Ocean. NMFS Southwest Fisheries Science Center Administrative Report LJ-02-29. 32 p.