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

Esquimault Harbour / Portage Inlet herring also spawn in late March, later than
herring in most other locations in the Strait of Georgia, and thus both geographic
isolation and differences in timing of spawning may be isolating mechanisms to
maintain the distinctiveness of these populations.
Beacham et al. (2002). Thus, in Lynn Canal Herring either one or both of these
mechanisms may be operating to make the population genetically distinct from others.
C. Comparison with Puget Sound Herring; Small et al.
(2005).
Small et al. (2005) determined that the Squaxin Pass herring population is isolated from
other herring in the Puget Sound, and that this isolation separates this population even
though they spawn at the same time as others.
The winter spawn timing of Squaxin Pass herring overlaps with other [Puget
Sound] herring spawn timings, but Squaxin Pass is the most physically isolated of
the [Puget Sound] populations in the study. In addition to threading their way
down to the southern reaches of [Puget Sound], Squaxin Pass herring must
negotiate a glacial sill at the Tacoma Narrows approximately 30 km northeast of
the spawning area. Herring from north of the Tacoma Narrows may be
unmotivated to explore into the region if aggregation sizes are small (Ware and
Schweigert 2001) and if spawning habitat is available at their natal sites. The
isolation of Squaxin Pass may be similar to Esquimalt Harbor on the Southern
Coast of Vancouver Island (Beacham et al. 2002) or Bras d’Or Lake along Nova
Scotia (McPherson et al. 2004), where geographic isolation promoted genetic
divergence.
(Small et al. 2005).
In addition, Small et al. (2004) hypothesizes that Pacific Herring may show
undifferentiated genetics between populations simply by chance.
The most puzzling result from this study is our failure to detect differentiation
between herring from the Bering Sea and Prince William Sound in Alaska.
Allozyme analysis (Grant and Utter 1984), microsatellites (O’Connell et al. 1998)
and mitochondrial analysis (Bentzen et al. 1998) report significant genetic
differences between herring collected from these locations. By increasing the
number of microsatellite loci, we expected to increase the resolution of their
genetic relationship. The high stray rate reported for BC herring (Ware and
Schweigert 2001) is unlikely between Norton Sound and Prince William Sound, a
minimum distance of around 3000 kilometers. Ware et al. (2000) found that of
the herring that strayed, less than 8% dispersed 800 or more kilometers. This lack
of observed differentiation between spawners from Norton Sound and Prince
VI