Variability in maturity and growth in a heavily exploited stock: whiting (Merlangius merlangus L.) in the Irish Sea |
| |
| Institution: | 1. Department of Agricultural and Environmental Sciences, Queens University Belfast, Newforge Lane, Belfast BT9 5PX, UK;2. Department of Agriculture and Rural Development, Agricultural and Environmental Sciences Division, Newforge Lane, Belfast BT9 5PX, UK;3. Department of Agriculture and Rural Development, Biometrics Division, Newforge Lane, Belfast BT9 5PX, UK;1. Instituto de Investigaciones Biotecnológicas-Instituto Tecnológico de Chascomús/Universidad Nacional de General San Martín-Consejo Nacional de Investigaciones Científicas y Técnicas (IIB-INTECH/UNSAM-CONICET), Chascomús, Argentina;2. Instituto Nacional de Tecnología Agropecuaria (INTA), Chascomús, Argentina;3. IEGEBA CONICET-UBA, Argentina;4. Departamento de Biodiversidad y Biología Facultad de Ciencias Exactas y Naturales Universidad de Buenos Aires, PROPLAME-PRHIDEB (CONICET), Argentina;1. Blue Ventures Conservation, Omnibus Business Centre, 39-41 North Road, London N7 9DP, United Kingdom;2. Centre for Ecology and Conservation, College of Life and Environmental Sciences, University of Exeter, Cornwall Campus, Penryn TR10 9FE, United Kingdom;1. Laboratoire de Biotechnologie, Agriculture et Valorisation des Ressources Biologiques, UFR Biosciences, Université Félix Houphouët Boigny d’Abidjan-Cocody, 22 BP 582 Abidjan 22, Côte d''Ivoire;2. Centre Suisse de Recherches Scientifiques en Côte d’Ivoire, 01 BP 1303 Abidjan 01, Côte d''Ivoire;3. Unité de Formation et de Recherche d’Environnement, Université Jean Lorougnon Guédé, BP 150 Daloa, Côte d''Ivoire;4. Laboratoire de Zoologie et Biologie Animale, Université Félix Houphouët Boigny d’Abidjan-Cocody, Côte d''Ivoire;5. Institute for Development, Ecology, Conservation and Cooperation, via G. Tomasi di 11 Lampedusa 33, I-00144 Rome, Italy;6. Laboratoire d’Ecologie et d’Ecophysiologie, Université de Lomé, Lomé, Togo;7. Department of Animal and Applied Biology, Rivers State University of Science and Technology, Port Harcourt, Rivers State, Nigeria;8. Laboratoire Evolution et Diversité Biologique (EDB), CNRS/UPS/IRD, Université Toulouse III Paul Sabatier – Bâtiment 4R1, 118 route de Narbonne, 31062 Toulouse cedex 9, France;9. Centro Interdisciplinar de Investigação Marinha e Ambiental (CIIMAR), Universidade do Porto, Terminal de Cruzeiros do Porto de Leixões, Av. General Norton de Matos, s/n, 4450-208 Porto, Portugal;1. Centro APTA do Pescado Marinho, Instituto de Pesca, Av. Bartolomeu Gusmão, 192 - Ponta da Praia, CEP: 11030-500, Santos, SP, Brazil;2. Programa de Pós-graduação do Instituto de Pesca, Av. Francisco Matarazzo, 455 - Caixa Postal 61070, CEP: 05001-970, São Paulo, SP, Brazil;3. Embrapa Pesca e Aquicultura, Prolongamento da Av. NS 10, cruzamento com a Av. LO 18 Sentido Norte Loteamento Água Fria, 77008-900, Palmas, TO, Brazil;1. Key Laboratory of Sustainable Development of Marine Fisheries, Ministry of Agriculture and Rural Affairs, Shandong Provincial Key Laboratory of Fishery Resources and Ecological Environment, Yellow Sea Fisheries Research Institute, Chinese Academy of Fishery Sciences, Qingdao 266071, China;2. Shandong Changdao Fishery Resources National Field Observation and Research Station, Yantai, 265800, China;3. School of Biosciences, The University of Melbourne, Parkville, Australia |
| |
| Abstract: | This paper examines the relationships between maturity, length and age of whiting sampled on a length-stratified basis from groundfish surveys of the Irish Sea during spawning in spring 1992–2001. Maturity, defined by the triggering of vitellogenesis or milt production, was a function of both length and age. Proportions of mature individuals in 1-year-old males increased successively from almost zero in length classes below 15 cm to around 0.9 at 25 cm, whilst almost all 2-year-old males were mature from their smallest length of around 19 cm. Maturity in females was more strongly linked to age than to length. Most 1-year-old females were immature, the proportion of mature individuals not exceeding 0.3 in any length class. Most 2-year-old females were mature and immature fish were found in the smallest length classes only (20–25 cm). Almost all 3-year-olds of both sexes were mature in all length classes. Proportions of mature individuals in 1-year-olds increased substantially after 1997, particularly in males. Significant positive cross-correlation between proportion mature and mean length was found for 1-year-olds of both sexes. Length at 50% maturity (L50) averaged around 19 cm in males and 22 cm in females. Variability in L50 was negatively cross-correlated with average sea surface temperature in the preceding year. There is no evidence for substantial changes in maturity of whiting since the 1950s, despite an order-of-magnitude reduction in biomass caused by high fishing mortality. Concomitant decreases in mean length-at-age and weight-at-age in recent decades indicate that conditions may have been unfavourable for compensatory changes in maturation. |
| |
| Keywords: | |
| 本文献已被 ScienceDirect 等数据库收录！ |
|
