Petition to List Lynn Canal Pacific Herring under the Endangered ...

significant genetic heterogeneity should be interpreted with caution, and where
feasible, additional sources of information shold be sought (e.g. Jennings and
Beverton 1991), or conservative measures deployed (Leslie and Grant 1990).
(Carvalho and Hauser 1994).
4. Significant to the Ecosystem
Herring are important prey species for many species, including the ESA listed
Steller Sea Lion and the Central North Pacific Humpback Whale. If Lynn Canal Herring
were rendered extinct, or extirpated, the Steller sea lion and the Humpback Whales would
lose a critical food resource. According to the NMFS Alaska Regional Office:
Pacific herring (Clupea pallasi) play a “key role in subarctic Pacific pelagic
ecosystems by being in an intermediary trophic position between plankton and
consumers of herring such as other fishes, birds and mammals” (Kline 2001).
Pacific herring are an important nutritional resource for several species of marine
mammals, supporting the nutritional needs of Steller sea lions, humpback whales,
and other species through direct consumption as well as secondary consumption,
when the mammals feed on other fish species such as pollock and salmon, which
also feed on herring. In dietary analyses of Steller sea lion populations foraging in
Berners Bay and Lynn Canal, herring have been found as a component of 90% of
the animals’ diets (J. Vollenweider, pers. comm.). Herring are an important prey
resource for marine mammals due to their high lipid concentrations and energy
content, measured at around 4.5 to 8.1 kJ/g wet mass (Paul and Paul 1998,
Anthony et al. 2000). During their different life stages, herring are also an
important prey resource for several Steller sea lion prey species, including:
pollock, salmon and Pacific cod.
(NMFS 2005a: 58).
In addition to being an important prey species for ESA-listed sea lions and
whales, Pacific Herring share predation pressures with the Eulachon (Thaleichthys
pacificus), which is also much reduced in Lynn Canal (NMFS 2005a). Predators
commonly congregate at both herring and eulachon spawning runs (Wilson 2003). Bald
Eagles by the hundreds and gulls (Larus spp.) numbering in the tens of thousands eagerly
await the arrival of spawning fish. Eulachon occur only on the coast of northwestern
North America, from northern California to Alaska (reviewed by Willson 2003). They
are anadromous fish, spawning in freshwater streams, unlike herring which spawn in
partially saline waters.
Pacific Herring and Eulachon rely upon each others sheer biomass to overwhelm
predators during breeding in late spring. Eulachon are an essential prey for sturgeon, a
species supporting a large commercial fishery (Willson 2003). Should Lynn Canal
Herring go extinct, Eulachon would lose an important partner during the breeding season.
With the loss of herring, Eulachon would be even more susceptible to extinction
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