Volumes

by publication dates
December 2023 (2)
May 2023 (1)
October 2022 (1)
September 2022 (2)
August 2022 (1)
April 2022 (1)
December 2021 (1)
November 2021 (1)
October 2021 (1)
September 2021 (1)
January 2021 (1)
December 2020 (1)
November 2020 (1)
October 2020 (1)
July 2020 (1)
June 2020 (2)
January 2020 (1)
May 2019 (1)
April 2019 (1)
March 2019 (1)
January 2019 (1)
January 2018 (1)
December 2017 (1)
October 2017 (1)
July 2017 (1)
December 2016 (2)
November 2016 (1)
October 2016 (1)
February 2016 (1)
December 2015 (4)
September 2015 (2)
July 2015 (1)
March 2015 (1)
December 2014 (3)
July 2014 (2)
May 2014 (1)
December 2013 (4)
October 2013 (1)
March 2013 (1)
January 2013 (1)
December 2012 (6)
October 2012 (2)
July 2012 (1)
January 2012 (1)
December 2011 (3)
November 2011 (1)
October 2011 (1)
September 2011 (1)
August 2011 (1)
May 2011 (1)
March 2011 (1)
February 2011 (1)
August 2010 (1)
June 2010 (2)
May 2010 (2)
April 2010 (1)
March 2010 (2)
February 2010 (2)
December 2009 (1)
October 2009 (6)
September 2009 (2)
August 2009 (2)
July 2009 (1)
April 2009 (1)
February 2009 (7)
January 2009 (5)
December 2008 (1)
October 2008 (1)
September 2008 (4)
August 2008 (4)
June 2008 (1)
May 2008 (1)
April 2008 (1)
February 2008 (4)
January 2008 (3)
December 2007 (5)
November 2007 (2)
August 2007 (1)
June 2007 (2)
May 2007 (4)
March 2007 (3)
February 2007 (1)
January 2007 (1)
November 2006 (1)
October 2006 (1)
September 2006 (3)
June 2006 (1)
May 2006 (1)
April 2006 (2)
February 2006 (2)
January 2006 (2)
December 2005 (6)
November 2005 (1)
October 2005 (5)
September 2005 (1)
June 2005 (1)
April 2005 (3)
March 2005 (16)
February 2005 (4)
January 2005 (6)
December 2004 (2)
November 2004 (7)
October 2004 (1)
September 2004 (12)
December 2003 (4)
October 2003 (37)
March 2003 (13)
December 2002 (7)
December 2001 (7)
December 2000 (34)
October 1999 (21)
November 1998 (6)
October 1998 (18)
December 1997 (28)
April 1997 (7)
October 1996 (13)
September 1996 (1)
April 1996 (9)
October 1994 (8)
July 1994 (9)
December 1993 (1)
December 1992 (26)
January 1992 (9)
February 1991 (9)
December 1990 (3)
December 1989 (8)
October 1989 (9)
December 1988 (9)
December 1987 (11)
December 1986 (11)
December 1985 (10)
June 1985 (11)
November 1984 (12)
January 1984 (18)
July 1983 (1)
December 1982 (12)
May 1982 (9)
November 1981 (12)
November 1980 (12)


JNAFS

30

U. Skúladóttir, Gunnar Pétursson and
Stefan H. Brynjólfsson

Marine Research Institute, Skúlagata 4, P.O. Box 1390, 121 Reykjavík, Iceland

Publication (Upload) date: 30 March 2007

SKÚLADÓTTIR, U., G. PÉTURSSON, and S. H. BRYNJÓLFSSON. 2007. The Biology of Northern Shrimp (Pandalus borealis) on the Flemish Cap. J. Northw. Atl. Fish. Sci., 37: 147–164. https://doi.org/10.2960/J.v37.m571

 

Abstract

This study reports on various biological features in the life history of northern shrimp (Pandalus borealis) on Flemish Cap. Northern shrimp on Flemish Cap are males for approximately their first three years. Then usually half change sex at age four years, and the rest at age five years, to become females from then on. Small shrimp are generally found at lesser depth than the larger ones so the size of shrimp increases with depth, especially that of males. Larger females seem to move to shallower waters in March when hatching starts. The size at sex change (L50) and the maximum length (Lmax) are studied within and between seasons. Both L50 and Lmax have decreased in recent years. L50 was 22.5 mm CL on average in the seasons 1996/1997-2003/2004, but has decreased from 23.2 mm CL in 1997/1998 to 22.4 mm CL in 2003/2004 (Icelandic commercial data) and from 24.3 mm CL in 1994 to 20.9 mm CL in 2003 (EU survey data). Also Lmax has decreased from 29.8 mm CL in 1996/1997 to 28.0 mm CL in 2003/2004 (Icelandic commercial data). In spite of this, there is an invariant relationship between L50 and Lmax, where L50 is about 80% of the average Lmax of northern shrimp on Flemish cap. This supports the theory of Charnov and Skúladóttir (2000) on the invariant relationship between L50 and Lmax in sex changing organisms. The same is found in Icelandic offshore waters and the Denmark Strait. The decline in L50 could be related to the observed increase in temperature at 150 m in the last decade from 2.6°C in the years 1992–1996 to 3.5°C in 1997–2003. The sudden decline in the female biomass of shrimp on Flemish Cap between 1992 and 1994 appears to coincide with a drop in the age at sex change (A50) by one year in 1995 and 1996. Moreover, the increase in biomass of shrimp follows the disappearance of cod in the mid-1990s. As female shrimp biomass increased there was a delay in changing sex, showing the versatility of shrimp on Flemish Cap in adjusting to changes in sex-ratio. Growth of shrimp was fast in the earlier years and slower in later years indicating that food may be a limiting factor. The growth during the earlier years is faster than that of northern shrimp in the Barents Sea. Compared to other areas in the 1980s, the growth is slightly faster than that of the warm inshore waters of Iceland, but much slower than the growth of shrimp in the inshore waters of Sweden. The ovigerous period is studied for the first time on Flemish Cap and is estimated to be about eight months.

Key words: growth, maximum length, ovigerous periods, Pandalus borealis, sequential hermaphrodite, size at sex change.

PDF

 

Download Citation Data

 


Citation to clipboard

Reference management software (Endnote, Mendeley, RefWords, Zotero & most other reference management software)

LaTex, BibDesk & other specific software
Citation: SKÚLADÓTTIR, U., G. PÉTURSSON, and S. H. BRYNJÓLFSSON. 2007. The Biology of Northern Shrimp (Pandalus borealis) on the Flemish Cap. J. Northw. Atl. Fish. Sci., 37: 147–164. https://doi.org/10.2960/J.v37.m571
Actions: E-mail | Permalink |