[Birdbycatch] Fwd: [SEABIRD] Threatened Seabirds Discussion Forum: new topics

Thu, 24 Apr 2003 09:20:04 -0700

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>From: "Deon Nel" <dnel@savethealbatross.org.za>
>To: "Seabird Listserver" <seabird@groa.uct.ac.za>
>Subject: [SEABIRD] Threatened Seabirds Discussion Forum: new topics
>Date: Thu, 24 Apr 2003 09:30:58 +0200
>X-Mailer: Microsoft Outlook Express 6.00.2600.0000
>Sender: owner-seabird@groa.uct.ac.za
>
>Dear all
>
>The following two discussion topics have been posted on the Threatened=20
>Seabirds Discussion Forum=20
>(<http://www.birdlife.org/action/science/species/globally_tbu/gtbu_main.htm=
l>http://www.birdlife.org/action/science/species/globally_tbu/gtbu_main.html=
=20
>and click on the red Globally Threatened Bird Forums)
>
>1. Laysan Albatross - list as Critical?
>
>2. Sooty Albatross - Upgrade to Endangered?
>
>If you have any comments please do so directly on the Forum site or=20
>alternatively you can send your comments directly to me?
>
>Kind regards
>
>Deon
>
><http://isuzu49.webcrossing.com/WebX?13@@.2cba2669>Threatened Seabirds
>
>Laysan Albatross - list as Critical?
>
><http://isuzu49.webcrossing.com/WebX?13@@.2cba2937>Initial MessageMessage=
 #-1
>Posted by: Deon Nel Date: Apr 23, 2003.
>
>The Laysan Albatross Phoebastria immutabilis is currently considered as=20
>Least Concern. It breeds at 15 sites (nine with populations of greater=20
>than 100 pairs), mostly in the Northwestern Hawaiian Islands (USA) with=20
>fewer than 500 nests in small colonies in Japan and Mexico. The largest=20
>colony is at Midway Atoll where 387,854 active nests were counted in 1996.=
=20
>The second largest colony is at Laysan Island where 55,500 pairs were=20
>estimated in 1999. Population sizes at monitored colonies increased=20
>between 1980 and 1995 but have never reached reached the densities=20
>observed prior to large-scale harvests for feathers in the early 1900s.=20
>Standardized counts are done each year at two colonies: at Laysan,=20
>breeding pairs have declined by 62% since 1992 and 72% since 1997; at Tern=
=20
>Island, populations increased between 1980 and 1995 but have declined by=20
>62.5% since that time. Numbers of breeding birds in sample plots at the=20
>Midway colony have declined by similar magnitudes during this time. More=20
>recent information has shown a 33% decline during 1992-2002 (3.3% per=20
>annum) in the Northwestern Hawaiian Islands where 90% of the global=20
>population is found (data from USF&WS 2002). The species is killed in=20
>pelagic (Crowder & Myers 2001) and demersal longline fisheries (Stehn et=20
>al. 2001) in the North Pacific as well as in illegal high seas driftnet=20
>operations. It is estimated that pelagic longliners in the North Pacific=20
>kill approximately 10,000 Laysan Albatrosses each year, while demersal=20
>longline operations in the Bering and Alaskan Sea kill in the region 700=20
>birds per year (Crowder & Myers 2001). Prior to its closure, the high seas=
=20
>driftnet fishery killed over 17,500 P. immutabilis in 1990 alone. Other=20
>threats include contaminants, oiling, plastic ingestion, human=20
>disturbance, conflicts with aircraft. Dogs kill adults and chicks on=20
>inhabited islands in Hawaii. The generation length in this species is 28.5=
=20
>years (data from Schreiber and Burger 2000), yielding a trend period of 86=
=20
>years. If we conservatively assume that the 10% of the population which=20
>occurs outside of the Northwestern Hawaiian Islands are stable, and a=20
>recorded population decline 3.3% per annum for the NW Hawaiian Islands=20
>(1992-2002), and if such a decline is extrapolated into the future, the=20
>total decline over 86 years would be 93%, triggering criterion A4d at the=
=20
>Critical level.
>
>
>----------
>Sooty Albatross - Upgrade to Endangered?
>
><http://isuzu49.webcrossing.com/WebX?13@@.2cba2936>Initial MessageMessage=
 #-1
>Posted by: Deon Nel Date: Apr 23, 2003.
>
>The Sooty Albatross Phoebetria fusca is currently classified as Vulnerable=
=20
>by Birdlife International (2000), because it is inferred to have suffered=
=20
>an overall population reduction of more than 20% over 60 years (3=20
>generations). Gough Island in the central South Atlantic holds the largest=
=20
>population of sooty albatrosses with an estimate of 5,000 - 10,000 pairs=20
>(Richardson 1984). Counts of incubating pairs on Gough Island in October=20
>2000 suggest that the coastal population of Gough Island is likely to be=20
>around 2,620 pairs (95% CI of 1,500 to 3,740 pairs) and that the total=20
>population on the island (inland and coastal pairs) is likely to be no=20
>greater than 5000 pairs. Scan counts of coastal cliffs in 2000 recorded an=
=20
>average of 62 =B1 2.5 birds/km (from 10 sites covering 2.6km of cliff). In=
=20
>contrast, Richardson (1984) recorded an average of 153 birds/km in 1972=20
>(from a total of 2.3km of cliff scan-counted): over twice the mean density=
=20
>of birds breeding in the 2000 season. If the density of birds counted in=20
>1972 was representative of the whole island, then the coastal population=20
>may have been around 6425 pairs in comparison to the estimated 2620 pairs=
=20
>breeding in the 2000 season. This represents a decline of nearly 60% over=
=20
>28 years, with an annual decline rate of 3.2%. This decrease corresponds=20
>closely with decreases observed at other breeding sites. Numbers on Marion=
=20
>Island have decreased at an annual rate of 2.6% over 25 seasons (Crawford=
=20
>et al. in press) and on Possession Island numbers have declined at 6.9% a=
=20
>year over a 30-year period and are projected to continue to decline at=20
>around 3% a year from 1995 (Weimerskirch & Jouventin 1998). Gough Island=20
>(5,000 - 10,000 pairs), Marion and Prince Edward Islands (1,539 pairs) and=
=20
>the Crozet Islands (2,620 pairs) hold between 67-71% of the total=20
>estimated breeding population of 12,500 - 19,000 pairs (Birdlife=20
>International 2000). If the decline rates recorded on Marion and=20
>Possession Island are representative of the decreases on Marion and Prince=
=20
>Edward Islands and all of the islands in the Crozet group, then the sooty=
=20
>albatross is likely to have experienced a considerable decrease in global=
=20
>numbers. Using the observed rates of decrease on Gough (3.2%), Marion=20
>(2.6%) and Possession (6.9% from 1966-95, 3% from 1995) and a generation=20
>length of 30 years (where generation length (GL) is calculated as GL =3D1/m=
=20
>+b and median age of first breeding (b) =3D 10 years, and annual adult=20
>mortality (m) is 0.05). Then over 3 generations the population is likely=20
>to decline by 76%, thus qualifying as endangered under the A4 criterion=20
>(decline >50% over 3 generations; Birdlife International 2000). Any=20
>comments on this? Regards, Richard Cuthbert & Deon Nel
>
>
>----------
>View this discussion, and post a reply at=20
><http://isuzu49.webcrossing.com/WebX?13@@.2cba2936>Globally Threatened=20
>Bird Forums.
>
>Use the <http://isuzu49.webcrossing.com/WebX?280@@.1de4282b>unsubscribe=20
>form to cancel your email subscription.

Elizabeth Mitchell
P.O. Box 933
Eugene, Oregon 97440
U.S.A.
Tel: 541/ 935-0858
Message Tel: 541/344-5503
E-mail: emitch@efn.org

 =20
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<blockquote type=3Dcite class=3Dcite cite>From: &quot;Deon Nel&quot;
&lt;dnel@savethealbatross.org.za&gt; 
To: &quot;Seabird Listserver&quot; &lt;seabird@groa.uct.ac.za&gt; 
Subject: [SEABIRD] Threatened Seabirds Discussion Forum: new topics 
Date: Thu, 24 Apr 2003 09:30:58 +0200 
X-Mailer: Microsoft Outlook Express 6.00.2600.0000 
Sender: owner-seabird@groa.uct.ac.za 
 
Dear all 
 
The following two discussion topics have been
posted on the Threatened Seabirds Discussion Forum
(<a href=3D"http://www.birdlife.org/action/science/species/globally_tbu/gtbu=
_main.html">http://www.birdlife.org/action/science/species/globally_tbu/gtbu=
_main.html</a>
and click on the red Globally Threatened Bird Forums)&nbsp; 
 
1. Laysan Albatross - list as Critical? 
 
2. Sooty Albatross - Upgrade to Endangered? 
 
If you have any comments please do so directly on the Forum site or
alternatively you can send your comments directly to me? 
 
Kind regards 
 
Deon 
 
<a href=3D"http://isuzu49.webcrossing.com/WebX?13@@.2cba2669">Threate=
ned
Seabirds</a> 
 
Laysan Albatross - list as Critical? 
 
<a href=3D"http://isuzu49.webcrossing.com/WebX?13@@.2cba2937">Initial
MessageMessage #-1</a> 
Posted by: Deon Nel Date: Apr 23, 2003. 
 
The Laysan Albatross Phoebastria immutabilis is currently considered as
Least Concern. It breeds at 15 sites (nine with populations of greater
than 100 pairs), mostly in the Northwestern Hawaiian Islands (USA) with
fewer than 500 nests in small colonies in Japan and Mexico. The largest
colony is at Midway Atoll where 387,854 active nests were counted in
1996. The second largest colony is at Laysan Island where 55,500 pairs
were estimated in 1999. Population sizes at monitored colonies increased
between 1980 and 1995 but have never reached reached the densities
observed prior to large-scale harvests for feathers in the early 1900s.
Standardized counts are done each year at two colonies: at Laysan,
breeding pairs have declined by 62% since 1992 and 72% since 1997; at
Tern Island, populations increased between 1980 and 1995 but have
declined by 62.5% since that time. Numbers of breeding birds in sample
plots at the Midway colony have declined by similar magnitudes during
this time. More recent information has shown a 33% decline during
1992-2002 (3.3% per annum) in the Northwestern Hawaiian Islands where 90%
of the global population is found (data from USF&amp;WS 2002). The
species is killed in pelagic (Crowder &amp; Myers 2001) and demersal
longline fisheries (Stehn et al. 2001) in the North Pacific as well as in
illegal high seas driftnet operations. It is estimated that pelagic
longliners in the North Pacific kill approximately 10,000 Laysan
Albatrosses each year, while demersal longline operations in the Bering
and Alaskan Sea kill in the region 700 birds per year (Crowder &amp;
Myers 2001). Prior to its closure, the high seas driftnet fishery killed
over 17,500 P. immutabilis in 1990 alone. Other threats include
contaminants, oiling, plastic ingestion, human disturbance, conflicts
with aircraft. Dogs kill adults and chicks on inhabited islands in
Hawaii. The generation length in this species is 28.5 years (data from
Schreiber and Burger 2000), yielding a trend period of 86 years. If we
conservatively assume that the 10% of the population which occurs outside
of the Northwestern Hawaiian Islands are stable, and a recorded
population decline 3.3% per annum for the NW Hawaiian Islands
(1992-2002), and if such a decline is extrapolated into the future, the
total decline over 86 years would be 93%, triggering criterion A4d at the
Critical level. 
 
<hr>
Sooty Albatross - Upgrade to Endangered? 
 
<a href=3D"http://isuzu49.webcrossing.com/WebX?13@@.2cba2936">Initial
MessageMessage #-1</a> 
Posted by: Deon Nel Date: Apr 23, 2003. 
 
The Sooty Albatross Phoebetria fusca is currently classified as
Vulnerable by Birdlife International (2000), because it is inferred to
have suffered an overall population reduction of more than 20% over 60
years (3 generations). Gough Island in the central South Atlantic holds
the largest population of sooty albatrosses with an estimate of 5,000 -
10,000 pairs (Richardson 1984). Counts of incubating pairs on Gough
Island in October 2000 suggest that the coastal population of Gough
Island is likely to be around 2,620 pairs (95% CI of 1,500 to 3,740
pairs) and that the total population on the island (inland and coastal
pairs) is likely to be no greater than 5000 pairs. Scan counts of coastal
cliffs in 2000 recorded an average of 62 =B1 2.5 birds/km (from 10 sites
covering 2.6km of cliff). In contrast, Richardson (1984) recorded an
average of 153 birds/km in 1972 (from a total of 2.3km of cliff
scan-counted): over twice the mean density of birds breeding in the 2000
season. If the density of birds counted in 1972 was representative of the
whole island, then the coastal population may have been around 6425 pairs
in comparison to the estimated 2620 pairs breeding in the 2000 season.
This represents a decline of nearly 60% over 28 years, with an annual
decline rate of 3.2%. This decrease corresponds closely with decreases
observed at other breeding sites. Numbers on Marion Island have decreased
at an annual rate of 2.6% over 25 seasons (Crawford et al. in press) and
on Possession Island numbers have declined at 6.9% a year over a 30-year
period and are projected to continue to decline at around 3% a year from
1995 (Weimerskirch &amp; Jouventin 1998). Gough Island (5,000 - 10,000
pairs), Marion and Prince Edward Islands (1,539 pairs) and the Crozet
Islands (2,620 pairs) hold between 67-71% of the total estimated breeding
population of 12,500 - 19,000 pairs (Birdlife International 2000). If the
decline rates recorded on Marion and Possession Island are representative
of the decreases on Marion and Prince Edward Islands and all of the
islands in the Crozet group, then the sooty albatross is likely to have
experienced a considerable decrease in global numbers. Using the observed
rates of decrease on Gough (3.2%), Marion (2.6%) and Possession (6.9%
from 1966-95, 3% from 1995) and a generation length of 30 years (where
generation length (GL) is calculated as GL =3D1/m +b and median age of
first breeding (b) =3D 10 years, and annual adult mortality (m) is 0.05).
Then over 3 generations the population is likely to decline by 76%, thus
qualifying as endangered under the A4 criterion (decline &gt;50% over 3
generations; Birdlife International 2000). Any comments on this? Regards,
Richard Cuthbert &amp; Deon Nel 
 
<hr>
View this discussion, and post a reply at
<a href=3D"http://isuzu49.webcrossing.com/WebX?13@@.2cba2936">Globally
Threatened Bird Forums</a>. 
 
Use the
<a href=3D"http://isuzu49.webcrossing.com/WebX?280@@.1de4282b">unsubscribe</=
a>
form to cancel your email subscription.</blockquote>
<x-sigsep></x-sigsep>
Elizabeth Mitchell 
P.O. Box 933 
Eugene, Oregon 97440 
U.S.A. 
Tel: 541/ 935-0858 
Message Tel: 541/344-5503 
E-mail: emitch@efn.org 
 
 
 
 
 
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