Resolution of multiple cohorts in the Loligo forbesi population from the west of Scotland
M A Collins, P R Boyle, G J Pierce, L N Key, S E Hughes, J Murphy
Length-frequency analysis was employed to resolve multiple cohorts in the Loligo forbesi population from coastal waters to the west. of Scotland. In both male and female squid two principal cohorts were identified, recruiting to the fished population in April and November. Both cohorts spawned during the winter months (November to April), producing a single extended spawning season, with the April recruits of larger size at spawning than the November recruits. In the males the April recruits appeared to separate into two cohorts of different growth rates, thus producing three rather than two sizes at maturity. The abundance of L. forbesi was low during the summer months, indicating that the squid had moved outside the range of the fishery, perhaps into deeper water. Abundance declined during the spawning season, which is interpreted as post-spawning mortality. Abundance declined earlier in the males than females, producing a female biased sex ratio during most of the spawning season. The two periods of recruitment are not compatible with a 1 year life cycle and single extended spawning season and explanations of this are discussed. (C) 1999 International Council for the Exploration of the Sea.
loliginid
IRISH WATERS
REPRODUCTIVE STRATEGIES
SCOTTISH WATERS
LIFE-HISTORY
LOLIGINIDAE
VULGARIS
Collins, M. A., Boyle, P. R., Pierce, G. J., Key, L. N., Hughes, S. E., & Murphy, J. (1999). Resolution of multiple cohorts in the Loligo forbesi population from the west of Scotland. ICES Journal of Marine Science, 56, 500-509.
Resolution of multiple cohorts in the Loligo forbesi population from the west of Scotland. / Collins, M A ; Boyle, P R ; Pierce, G J ; Key, L N ; Hughes, S E ; Murphy, J .
In: ICES Journal of Marine Science, Vol. 56, 1999, p. 500-509.
Collins, MA, Boyle, PR, Pierce, GJ, Key, LN, Hughes, SE & Murphy, J 1999, 'Resolution of multiple cohorts in the Loligo forbesi population from the west of Scotland', ICES Journal of Marine Science, vol. 56, pp. 500-509.
Collins MA, Boyle PR, Pierce GJ, Key LN, Hughes SE, Murphy J. Resolution of multiple cohorts in the Loligo forbesi population from the west of Scotland. ICES Journal of Marine Science. 1999;56:500-509.
Collins, M A ; Boyle, P R ; Pierce, G J ; Key, L N ; Hughes, S E ; Murphy, J . / Resolution of multiple cohorts in the Loligo forbesi population from the west of Scotland. In: ICES Journal of Marine Science. 1999 ; Vol. 56. pp. 500-509.
@article{298ab1c8644e4c1a999129e2b94d5276,
title = "Resolution of multiple cohorts in the Loligo forbesi population from the west of Scotland",
abstract = "Length-frequency analysis was employed to resolve multiple cohorts in the Loligo forbesi population from coastal waters to the west. of Scotland. In both male and female squid two principal cohorts were identified, recruiting to the fished population in April and November. Both cohorts spawned during the winter months (November to April), producing a single extended spawning season, with the April recruits of larger size at spawning than the November recruits. In the males the April recruits appeared to separate into two cohorts of different growth rates, thus producing three rather than two sizes at maturity. The abundance of L. forbesi was low during the summer months, indicating that the squid had moved outside the range of the fishery, perhaps into deeper water. Abundance declined during the spawning season, which is interpreted as post-spawning mortality. Abundance declined earlier in the males than females, producing a female biased sex ratio during most of the spawning season. The two periods of recruitment are not compatible with a 1 year life cycle and single extended spawning season and explanations of this are discussed. (C) 1999 International Council for the Exploration of the Sea.",
keywords = "squid, loliginid, growth, life history, IRISH WATERS, REPRODUCTIVE STRATEGIES, SCOTTISH WATERS, LIFE-HISTORY, CEPHALOPODA, LOLIGINIDAE, RECRUITMENT, VULGARIS, MATURATION, FISHERY",
author = "Collins, {M A} and Boyle, {P R} and Pierce, {G J} and Key, {L N} and Hughes, {S E} and J Murphy",
journal = "ICES Journal of Marine Science",
publisher = "Oxford University Press",
T1 - Resolution of multiple cohorts in the Loligo forbesi population from the west of Scotland
AU - Collins, M A
AU - Boyle, P R
AU - Pierce, G J
AU - Key, L N
AU - Hughes, S E
AU - Murphy, J
N2 - Length-frequency analysis was employed to resolve multiple cohorts in the Loligo forbesi population from coastal waters to the west. of Scotland. In both male and female squid two principal cohorts were identified, recruiting to the fished population in April and November. Both cohorts spawned during the winter months (November to April), producing a single extended spawning season, with the April recruits of larger size at spawning than the November recruits. In the males the April recruits appeared to separate into two cohorts of different growth rates, thus producing three rather than two sizes at maturity. The abundance of L. forbesi was low during the summer months, indicating that the squid had moved outside the range of the fishery, perhaps into deeper water. Abundance declined during the spawning season, which is interpreted as post-spawning mortality. Abundance declined earlier in the males than females, producing a female biased sex ratio during most of the spawning season. The two periods of recruitment are not compatible with a 1 year life cycle and single extended spawning season and explanations of this are discussed. (C) 1999 International Council for the Exploration of the Sea.
AB - Length-frequency analysis was employed to resolve multiple cohorts in the Loligo forbesi population from coastal waters to the west. of Scotland. In both male and female squid two principal cohorts were identified, recruiting to the fished population in April and November. Both cohorts spawned during the winter months (November to April), producing a single extended spawning season, with the April recruits of larger size at spawning than the November recruits. In the males the April recruits appeared to separate into two cohorts of different growth rates, thus producing three rather than two sizes at maturity. The abundance of L. forbesi was low during the summer months, indicating that the squid had moved outside the range of the fishery, perhaps into deeper water. Abundance declined during the spawning season, which is interpreted as post-spawning mortality. Abundance declined earlier in the males than females, producing a female biased sex ratio during most of the spawning season. The two periods of recruitment are not compatible with a 1 year life cycle and single extended spawning season and explanations of this are discussed. (C) 1999 International Council for the Exploration of the Sea.
KW - squid
KW - loliginid
KW - life history
KW - IRISH WATERS
KW - REPRODUCTIVE STRATEGIES
KW - SCOTTISH WATERS
KW - LIFE-HISTORY
KW - CEPHALOPODA
KW - LOLIGINIDAE
KW - RECRUITMENT
KW - VULGARIS
KW - MATURATION
KW - FISHERY
JO - ICES Journal of Marine Science
JF - ICES Journal of Marine Science