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Living apart together: Long-term coexistence of Baltic cod stocks associated with depth-specific habitat use. PLoS One 2022; 17:e0274476. [PMID: 36170259 PMCID: PMC9518848 DOI: 10.1371/journal.pone.0274476] [Citation(s) in RCA: 3] [Impact Index Per Article: 1.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 01/19/2022] [Accepted: 08/29/2022] [Indexed: 12/02/2022] Open
Abstract
Coexistence of fish populations (= stocks) of the same species is a common phenomenon. In the Baltic Sea, two genetically divergent stocks of Atlantic cod (Gadus morhua), Western Baltic cod (WBC) and Eastern Baltic cod (EBC), coexist in the Arkona Sea. Although the relative proportions of WBC and EBC in this area are considered in the current stock assessments, the mixing dynamics and ecological mechanisms underlying coexistence are not well understood. In this study, a genetically validated otolith shape analysis was used to develop the most comprehensive time series of annual stock mixing data (1977–2019) for WBC and EBC. Spatio-temporal mixing analysis confirmed that the two stocks coexist in the Arkona Sea, albeit with fluctuating mixing proportions over the 43-year observation period. Depth-stratified analysis revealed a strong correlation between capture depth and stock mixing patterns, with high proportions of WBC in shallower waters (48–61% in <20m) and increasing proportions of EBC in deeper waters (50–86% in 40-70m). Consistent depth-specific mixing patterns indicate stable differences in depth distribution and habitat use of WBC and EBC that may thus underlie the long-term coexistence of the two stocks in the Arkona Sea. These differences were also reflected in significantly different proportions of WBC and EBC in fisheries applying passive gears in shallower waters (more WBC) and active gears in deeper waters (more EBC). This highlights the potential for fishing gear-specific exploitation of different stocks, and calls for stronger consideration of capture depth and gear type in stock assessments. This novel evidence provides the basis for improved approaches to research, monitoring and management of Baltic cod stocks.
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Ruggeri P, Splendiani A, Di Muri C, Fioravanti T, Santojanni A, Leonori I, De Felice A, Biagiotti I, Carpi P, Arneri E, Nisi Cerioni P, Giovannotti M, Caputo Barucchi V. Coupling Demographic and Genetic Variability from Archived Collections of European Anchovy (Engraulis encrasicolus). PLoS One 2016; 11:e0151507. [PMID: 26982808 PMCID: PMC4794184 DOI: 10.1371/journal.pone.0151507] [Citation(s) in RCA: 11] [Impact Index Per Article: 1.4] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Received: 07/20/2015] [Accepted: 02/29/2016] [Indexed: 11/18/2022] Open
Abstract
It is well known that temporal fluctuations in small populations deeply influence evolutionary potential. Less well known is whether fluctuations can influence the evolutionary potentials of species with large census sizes. Here, we estimated genetic population parameters from as survey of polymorphic microsatellite DNA loci in archived otoliths from Adriatic European anchovy (Engraulis encrasicolus), a fish with large census sizes that supports numerous local fisheries. Stocks have fluctuated greatly over the past few decades, and the Adriatic fishery collapsed in 1987. Our results show a significant reduction of mean genetic parameters as a consequence of the population collapse. In addition, estimates of effective population size (Ne) are much smaller than those expected in a fishes with large population census sizes (Nc). Estimates of Ne indicate low effective population sizes, even before the population collapse. The ratio Ne/Ne ranged between 10-6 and 10-8, indicating a large discrepancy between the anchovy gene pool and population census size. Therefore, anchovy populations may be more vulnerable to fishery effort and environmental change than previously thought.
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Affiliation(s)
- Paolo Ruggeri
- Dipartimento di Scienze della Vita e dell’Ambiente, Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona, Italy
| | - Andrea Splendiani
- Dipartimento di Scienze della Vita e dell’Ambiente, Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona, Italy
| | - Cristina Di Muri
- Dipartimento di Scienze della Vita e dell’Ambiente, Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona, Italy
| | - Tatiana Fioravanti
- Dipartimento di Scienze della Vita e dell’Ambiente, Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona, Italy
| | - Alberto Santojanni
- Consiglio Nazionale delle Ricerche, Istituto di Scienze Marine Sezione Pesca Marittima, Largo Fiera della Pesca, 60125 Ancona, Italy
| | - Iole Leonori
- Consiglio Nazionale delle Ricerche, Istituto di Scienze Marine Sezione Pesca Marittima, Largo Fiera della Pesca, 60125 Ancona, Italy
| | - Andrea De Felice
- Consiglio Nazionale delle Ricerche, Istituto di Scienze Marine Sezione Pesca Marittima, Largo Fiera della Pesca, 60125 Ancona, Italy
| | - Ilaria Biagiotti
- Consiglio Nazionale delle Ricerche, Istituto di Scienze Marine Sezione Pesca Marittima, Largo Fiera della Pesca, 60125 Ancona, Italy
| | - Piera Carpi
- Consiglio Nazionale delle Ricerche, Istituto di Scienze Marine Sezione Pesca Marittima, Largo Fiera della Pesca, 60125 Ancona, Italy
| | - Enrico Arneri
- FAO-FIRF, Fisheries and Aquaculture Department, AdriaMed Project, Viale delle Terme di Caracalla, 00153 Roma, Italy
| | - Paola Nisi Cerioni
- Dipartimento di Scienze della Vita e dell’Ambiente, Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona, Italy
| | - Massimo Giovannotti
- Dipartimento di Scienze della Vita e dell’Ambiente, Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona, Italy
| | - Vincenzo Caputo Barucchi
- Dipartimento di Scienze della Vita e dell’Ambiente, Università Politecnica delle Marche, Via Brecce Bianche, 60131 Ancona, Italy
- Consiglio Nazionale delle Ricerche, Istituto di Scienze Marine Sezione Pesca Marittima, Largo Fiera della Pesca, 60125 Ancona, Italy
- * E-mail:
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Bonanomi S, Therkildsen NO, Hedeholm RB, Hemmer-Hansen J, Nielsen EE. The use of archived tags in retrospective genetic analysis of fish. Mol Ecol Resour 2013; 14:616-21. [PMID: 24299474 DOI: 10.1111/1755-0998.12211] [Citation(s) in RCA: 3] [Impact Index Per Article: 0.3] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 11/19/2013] [Accepted: 11/23/2013] [Indexed: 11/30/2022]
Abstract
Collections of historical tissue samples from fish (e.g. scales and otoliths) stored in museums and fisheries institutions are precious sources of DNA for conducting retrospective genetic analysis. However, in some cases, only external tags used for documentation of spatial dynamics of fish populations have been preserved. Here, we test the usefulness of fish tags as a source of DNA for genetic analysis. We extract DNA from historical tags from cod collected in Greenlandic waters between 1950 and 1968. We show that the quantity and quality of DNA recovered from tags is comparable to DNA from archived otoliths from the same individuals. Surprisingly, levels of cross-contamination do not seem to be significantly higher in DNA from external (tag) than internal (otolith) sources. Our study therefore demonstrates that historical tags can be a highly valuable source of DNA for retrospective genetic analysis of fish.
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Affiliation(s)
- Sara Bonanomi
- Technical University of Denmark, Section for Marine Living Resources, National Institute of Aquatic Resources, Vejlsøvej 39, DK-8600, Silkeborg, Denmark; Greenland Climate Research Centre, Greenland Institute of Natural Resources, Kivioq 2, PO Box 570, 3900, Nuuk, Greenland
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Cuveliers EL, Volckaert FAM, Rijnsdorp AD, Larmuseau MHD, Maes GE. Temporal genetic stability and high effective population size despite fisheries-induced life-history trait evolution in the North Sea sole. Mol Ecol 2011; 20:3555-68. [PMID: 21790820 DOI: 10.1111/j.1365-294x.2011.05196.x] [Citation(s) in RCA: 14] [Impact Index Per Article: 1.1] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Heavy fishing and other anthropogenic influences can have profound impact on a species' resilience to harvesting. Besides the decrease in the census and effective population size, strong declines in mature adults and recruiting individuals may lead to almost irreversible genetic changes in life-history traits. Here, we investigated the evolution of genetic diversity and effective population size in the heavily exploited sole (Solea solea), through the analysis of historical DNA from a collection of 1379 sole otoliths dating back from 1957. Despite documented shifts in life-history traits, neutral genetic diversity inferred from 11 microsatellite markers showed a remarkable stability over a period of 50 years of heavy fishing. Using simulations and corrections for fisheries induced demographic variation, both single-sample estimates and temporal estimates of effective population size (N(e) ) were always higher than 1000, suggesting that despite the severe census size decrease over a 50-year period of harvesting, genetic drift is probably not strong enough to significantly decrease the neutral diversity of this species in the North Sea. However, the inferred ratio of effective population size to the census size (N(e) /N(c) ) appears very small (10(-5) ), suggesting that overall only a low proportion of adults contribute to the next generation. The high N(e) level together with the low N(e) /N(c) ratio is probably caused by a combination of an equalized reproductive output of younger cohorts, a decrease in generation time and a large variance in reproductive success typical for marine species. Because strong evolutionary changes in age and size at first maturation have been observed for sole, changes in adaptive genetic variation should be further monitored to detect the evolutionary consequences of human-induced selection.
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Affiliation(s)
- E L Cuveliers
- Laboratory of Animal Diversity and Systematics, Katholieke Universiteit Leuven, Charles Deberiotstraat 32, B-3000 Leuven, Belgium
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