Publication Date:
2022-05-25
Description:
Author Posting. © The Author(s), 2013. This is the author's version of the work. It is posted here by permission of Elsevier B.V. for personal use, not for redistribution. The definitive version was published in Progress in Oceanography 116 (2013): 207–219, doi:10.1016/j.pocean.2013.07.009.
Description:
Similarly structured food web models of four coastal ecosystems (Northern California
Current, Central Gulf of Alaska, Georges Bank, southwestern Antarctic Peninsula) were used to
investigate competition among whales, fishes, pinnipeds, and humans. Two analysis strategies
simulated the effects of historic baleen and odontocete whale abundances across all trophic
levels: food web structure scenarios and time-dynamic scenarios. Direct competition between
whales and commercial fisheries is small at current whale abundances; whales and fisheries each
take similar proportions of annual pelagic fish production (4 - 7%). Scenarios show that as whale
populations grow, indirect competition between whales and fish for zooplankton would more
likely impact fishery production than would direct competition for fish between whales and
commercial fisheries. Increased baleen whale abundance would have greater and broader indirect
effects on upper trophic levels and fisheries than a similar increase in odontocete abundance.
Time-dynamic scenarios, which allow for the evolution of compensatory mechanisms, showed
more modest impacts than structural scenarios, which show the immediate impacts of altered
energy pathways.
Structural scenarios show that in terms of energy availability, there is potential for large
increases in whale abundance without major changes to existing food web structures and without
substantial reduction of fishery production. For each ecosystem, a five-fold increase in baleen
whale abundance could be supported with minor disruptions to existing energy flow pathways.
However, such an increase would remain below historical population levels for many cetaceans.
A larger expansion (20X) could be accommodated only with large reductions in energy flow to
competitor groups. The scope for odontocete expansion varies between ecosystems but can be
restricted because they feed at higher, less productive trophic levels.
Description:
This study was supported by a grant from the NSF GLOBEC Panregional
Synthesis program (NSF 0814494), and NSF ANT 0944411 to DGA.
Keywords:
End-to-end model
;
Baleen whales
;
Odontocete whales
;
Pinnipeds
;
Conservation
;
Competition
;
Food web
Repository Name:
Woods Hole Open Access Server
Type:
Preprint
Format:
application/pdf
Permalink
