Subject: Seals:Impact of pinnipeds on sandy and rocky shores (fwd)

Mike Williamson (
Sun, 7 Dec 1997 21:23:29 -0500 (EST)

Smith,RIL (1988): Destruction of Antarctic terrestrial ecosystems by a
rapidly increasing fur seal population. Biological Conservation 45(1),
 <The terrestrial environment of Signay Island, South Orkney Islands,
maritime Antarctic, is undergoing rapid and possibly irreversible change
caused by a natural biological agent. During the past decade there has
been a dramatic increase in the number of Antarctic fur seals
Arctocephalus gazella coming a shore on the island during the short
summers. It is not known whether significant numbers of seals were present
on the island prior to the initiation of commerical hunting in the early
1820s. The impact that the continuing increase of these seals had made on
the island's terrestrial and freshwater environments has been sudden and
locally devastating. The fragile cryptogam-dominated vegetation has
suffered physical damage from which it may be impossible to recover. These
seals are also frequenting several of the islands's freshwater lakes which
are becoming increasingly eutrophic. The long-term implications of this
impact are causing serious concern for the future of the lowland
terrestrial and freshwater ecosystems on Signy Island if the fur seal
population continues to increase.>

Dadswell,MJ; Rulifson,RA (1994): Macrotidal estuaries: A region of
collision between migratory marine animals and tidal power development.
Biological Journal of the Linnean Society 51(1-2), 93-113.
 <Macrotidal estuaries of the inner Bay of Fundy are utilized by large
numbers of migratory fishes, particularly dogfish, sturgeon, herring,
shad, Atlantic salmon and striped bass as well as by other migratory
marine animals, many of which have large body sizes (squid, Lamnid sharks,
seals and whales). Tagging experiments indicate the fishes originate from
stocks derived over the entire North American Atlantic coast from Florida
to Labrador. Population estimates suggest up to 2.0 times 10-6 adult
American shad (Alosa sapidissima) migrate through an individual embayment
each year. These migrations are an integral part of the life history of
the respective species and appear to be controlled in part by the near
shore movements of ocean currents. In other regions of the world similar
macrotidal estuaries exist (Cook Inlet, Alaska; Severn Estuary, U.K.) and
they, like the Bay of Fundy, are linked in continuum to the local ocean
currents. We propose that marine animals utilize all these regions in a
manner similar to the Bay of Fundy estuaries and properly designed surveys
will reveal their presence. Fish passage studies utilizing the Annapolis
estuary low-head, tidal turbine on the Bay of Fundy have shown that
turbine related mortality of 20-80% per passage occurs depending on fish
species, fish size and the efficiency of turbine operation. We suggest
that introduction of tidal turbines into open ocean current systems will
cause widespread impact on marine populations resulting in significant
declines in abundance.>

-----Original Message-----
From: Thomas Peschak <>
Date: Friday, December 05, 1997 2:28 PM
Subject: Impact of Pinnipeds on rocky and sandy shores

>I am currently in the process of writing a research proposal for a PhD
>the research topic being : The impact of Pinnipeds on Rocky and Sandy
>Flora and Fauna.
>Having undertaken a literature search I have come up with only one paper
>this topic:
>Boal.J, 1980 Pacific Harbour Seal hault out impact on the Rocky Midtidal
>Marine Ecology Progress Series, Vol.2:265-269
>I can't believe that this is the only bit of information out there, and
>would like to know weather anybody
>knows of other such studies. ( Published, unpublished, grey literature,
>personal observations, etc. )
>Thanks for all responses in advance
>Thomas P. Peschak
>University of Plymouth

  ____   _   _   ___    _   ___     _
 /  __) | |_| | |    \ | | / __)   / / "If sponges didn't live in the
|  (__  |  _  | | () / | | \__ \  / /  ocean, imagine how much more water
 \____) |_| |_| |_|\_\ |_| (___/ /_/  there'd be."   - Stephen Wright
               Chris Hendry           
          MUN Biology Society (BIOS)  
            Department of Biology     
     Memorial University of Newfoundland