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<DIV><A href="http://www3.interscience.wiley.com/journal/118483233/home"><FONT
color=#000000>Journal of Fish Biology</FONT></A></DIV>
<DIV class=volIss><A
href="http://www3.interscience.wiley.com/journal/123201793/issue"><FONT
color=#000000>Volume 75 Issue
7</FONT></A>, Pages 1560 - 1576</DIV>
<DIV class=pubOnline>Published Online: 3 Dec 2009</DIV>
<DIV class=line> </DIV>
<DIV class=title-document xmlns="http://www.w3.org/1999/xhtml"><FONT
size=4>Spawning dynamics and biomass estimates of an anchovy <SPAN
class=i><EM>Engraulis australis</EM></SPAN> population in contrasting gulf and
shelf environments</FONT></DIV>
<DIV class=author-info xmlns="http://www.w3.org/1999/xhtml"><SPAN
class=name><SPAN class=forenames>W. F.</SPAN> <SPAN class=surname>D<SPAN
class=smallcapitals>immlich</SPAN></SPAN> <SUP><NOBR>*†‡</NOBR></SUP> </SPAN>,
<SPAN class=name><SPAN class=forenames>T. M.</SPAN> <SPAN class=surname>W<SPAN
class=smallcapitals>ard</SPAN></SPAN> <SUP><NOBR>†</NOBR></SUP> </SPAN><SPAN
class=smallcapitals>and</SPAN> <SPAN class=name><SPAN class=forenames>W.
G.</SPAN> <SPAN class=surname>B<SPAN class=smallcapitals>reed</SPAN></SPAN>
<SUP><NOBR>§</NOBR></SUP> </SPAN></DIV>
<DIV class=addresses xmlns="http://www.w3.org/1999/xhtml"><SPAN class=address><A
class=invisible-anchor name=a1> </A><SPAN id=a1> <SPAN
class=number><SUP><NOBR>*</NOBR></SUP> </SPAN><SPAN class=i><EM>School of Earth
and Environmental Sciences, University of Adelaide, Adelaide, South Australia
5005, Australia</EM></SPAN> </SPAN>, <A class=invisible-anchor
name=a2> </A><SPAN id=a2> <SPAN class=number><SUP><NOBR>†</NOBR></SUP>
</SPAN><SPAN class=i><EM>South Australian Research and Development Institute
(Aquatic Sciences), P.O. Box 120, Henley Beach, Adelaide, South Australia 5022,
Australia</EM></SPAN> </SPAN><SPAN class=i><EM>and</EM></SPAN> <A
class=invisible-anchor name=a3> </A><SPAN id=a3> <SPAN
class=number><SUP><NOBR>§</NOBR></SUP> </SPAN><SPAN class=i><EM>Department of
Anatomical Sciences, University of Adelaide, Adelaide, South Australia 5005,
Australia</EM></SPAN> </SPAN></SPAN></DIV>
<DIV class=correspondence-address xmlns="http://www.w3.org/1999/xhtml"><SPAN
class=number><SUP><NOBR>‡</NOBR></SUP> </SPAN>Author to whom correspondence
should be addressed at present address: Marine Stewardship Council, 6-20
Elizabeth St, London SW1W 9RB, U.K. Tel.: +44 (0) 2078113325; fax: +44 (0)
2078113301; email: <A class=externallink
href="mailto:wetjens.dimmlich@msc.org"><FONT
color=#000000>wetjens.dimmlich@msc.org</FONT></A></DIV>
<DIV class=bpg40copyright> </DIV>
<DIV class=abstract-title id=Abstract><STRONG>ABSTRACT</STRONG></DIV>
<DIV class=abstract-content xmlns="http://www.w3.org/1999/xhtml"
xmlns:md="urn:mdransfi-functions"
xmlns:f="http://wiley.com/wispers/content/function"
xmlns:xs="http://www.w3.org/2001/XMLSchema">
<P class=para>The spawning biomass of Australian anchovy <SPAN
class=i><EM>Engraulis australis</EM></SPAN> in gulf and shelf waters of South
Australia was compared using the daily egg production method (DEPM). The total
survey area was 128 700 km<SUP><NOBR>2</NOBR></SUP> with recorded spawning areas
in gulf and shelf waters of 4898 and 44 618 km<SUP><NOBR>2</NOBR></SUP>,
respectively. High egg densities in the warm, shallow gulf waters were produced
by small, young (<1 year old) <SPAN class=i><EM>E. australis</EM></SPAN> that
spawned relatively small batches of eggs (<SPAN class=i><EM>c.</EM></SPAN> 855)
approximately every 3 days. In cooler, deeper shelf waters, where larger, older
<SPAN class=i><EM>E. australis</EM></SPAN> are found, lower egg densities
occurred despite individuals producing much larger batches of eggs (<SPAN
class=i><EM>c.</EM></SPAN> 15 572) approximately every 7 days. In shelf waters,
the highest densities were recorded at inshore sampling stations. Spawning
appeared to peak between 0000 and 0100 hours. Females were more abundant than
males in samples from both gulf and shelf waters with sex ratios of 0·61 and
0·56, respectively. The spawning biomass of <SPAN class=i><EM>E.
australis</EM></SPAN> in shelf waters was 101 522 t, whereas the estimate for
gulf waters was 25 374 t. Due to the differences in mean size of the spawning
females, however, <SPAN class=i><EM>c</EM></SPAN>. 6 ×
10<SUP><NOBR>9</NOBR></SUP><SPAN class=i><EM>E. australis</EM></SPAN> were
present in each region. The results support the hypothesis that variability in
habitat conditions may directly influence <SPAN class=i><EM>E.
australis</EM></SPAN> reproduction. A large reserve of young fish in the
relatively stable gulf environment may increase the resilience of the <SPAN
class=i><EM>E. australis</EM></SPAN> population in South Australia to
unfavourable interannual changes in offshore environmental
conditions.</P></DIV></FONT></BODY></HTML>