Aspects of anadromous Allis shad (Alosa alosa Linnaeus) and Twaite shad (Alosa fallax Lacépède) biology in four Irish Special Areas of Conservation (SACs): status, spawning indications and implications for conservation designation

King, James J.; Roche, William K.

doi:10.1007/s10750-008-9280-9

Cited by 16 publications

(10 citation statements)

References 12 publications

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“…GSI is a well-accepted index with which to identify the spawning time of fishes (King 1995), and a good agreement with maturity stages in this study indicates that both methods are valuable for this purpose. In the same manner, GSI and maturity stage were used to locate the spawning area of twaite shad.…”

Section: Discussionsupporting

confidence: 65%

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Stock recovery, spawning period and spawning area expansion of the twaite shad Alosa fallax in the Elbe estuary, southern North Sea

Magath¹,

Thiel²

2013

Endang. Species. Res.

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After a serious decline in the past, some twaite shad Alosa fallax populations have significantly recovered during the last decade. Although increasing numbers of the species occur in areas of the southern North Sea, detailed quantitative analyses have not been published on spawning stocks of specific North Sea estuaries. In this study, the development of the twaite shad spawning stock of the Elbe estuary, its spawning period and spawning area were determined using abundance data, gonad maturity information and the gonadosomatic index. Abundances were compared between the periods

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Section: Discussionsupporting

confidence: 65%

“…In contrast, adult fish are easier to obtain, and gonad maturity and gonadosomatic index (GSI) of adults could provide information on the spawning period and the spawning area (e.g. Massmann 1952, Maitland & Lyle 2005, King & Roche 2008.…”

Section: Introductionmentioning

confidence: 99%

Stock recovery, spawning period and spawning area expansion of the twaite shad Alosa fallax in the Elbe estuary, southern North Sea

Magath¹,

Thiel²

2013

Endang. Species. Res.

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“…Total genomic DNA was extracted using Invitrogen™ PureLink™ Genomic DNA Mini Kit following the manufacturer's instructions and visualized on 1.5% agarose gels. The number of gill rakers on the first left branchial arch, a morphological character commonly used to discriminate between A. alosa (>90 gill rakers) and A. fallax (<60 gill rakers), was counted under a binocular, following the recommendations of Sabatié () and King and Roche ().…”

Section: Methodsmentioning

confidence: 99%

Variable outcomes of hybridization between declining Alosa alosa and Alosa fallax

Taillebois¹,

Sabatino

Manicki³

et al. 2019

Evolutionary Applications

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Hybridization dynamics between co‐occurring species in environments where human‐mediated changes take place are important to quantify for furthering our understanding of human impacts on species evolution and for informing management. The allis shad Alosa alosa (Linnaeus, 1758) and twaite shad Alosa fallax (Lacépède, 1803), two clupeids sister species, have been severely impacted by human activities across Europe. The shrinkage of A. alosa distribution range along with the decline of the remaining populations' abundance threatens its persistence. The main objective was to evaluate the extent of hybridization and introgression between those interacting species. We developed a set of 77 species‐specific SNP loci that allowed a better resolution than morphological traits as they enabled the detection of hybrids up to the third generation. Variable rates of contemporary hybridization and introgression patterns were detected in 12 studied sites across the French Atlantic coast. Mitochondrial markers revealed a cyto‐nuclear discordance almost invariably involving A. alosa individuals with an A. fallax mitochondrial DNA and provided evidence of historical asymmetric introgression. Overall, contemporary and historical introgression revealed by nuclear and mitochondrial markers strongly suggests that a transfer of genes occurs from A. fallax toward A. alosa genome since at least four generations. Moreover, the outcomes of introgression greatly depend on the catchments where local processes are thought to occur. Undoubtedly, interspecific interaction and gene flow should not be overlooked when considering the management of those species.

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“…The occurrence of hybridization among Allis and Twaite shad in the four Irish tidal freshwater SACs is considered a reflection of impedance to upstream migration caused by both natural and artificial barriers (King and Roche, 2008).…”

Section: Discussionmentioning

confidence: 99%

“…Information on shad was collected via trial netting surveys for both adult and juvenile fish. The bulk of information came from by‐catch of commercial salmon netsmen operating in the estuary of the R. Nore and in the downstream waters of Waterford Harbour (King and Roche, 2008).…”

Section: Methodsmentioning

confidence: 99%

Comparison of field- and GIS-based assessments of barriers to Atlantic salmon migration: a case study in the Nore Catchment, Republic of Ireland

Gargan

Roche

Keane

et al. 2011

Journal of Applied Ichthyology

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SummaryIn Ireland, the Water Framework Directive (WFD) Freshwater Morphology Programme of Measures and Standards (POMS) identified barriers to fish migration as one of the principal issues placing channels Ôat riskÕ in terms of failing to achieve hydromorphology status. To quantify the degree of risk posed, and to develop methods to appraise and quantify risk associated with barriers, the POMS undertook a pilot study on the River Nore catchment. This provided an opportunity to compare the outcomes of an intensive fieldbased qualitative assessment of barriers to fish migration with a rules-based appraisal of risk, based on layers of georeferenced data, in a Geographical Information System (GIS) analysis. The underlying aim of this risk-based assessment was the restoration of the fisheries resource, in the context of WFD, grounded on knowledge-based assessment. The comparison focused on the Atlantic salmon (Salmo salar L.). A rapid-assessment field survey compiled a geo-referenced inventory of 508 structures (497 artificial and 11 natural) and classified each with regard to presumed risk of preventing the upstream migration of adult Atlantic salmon. This inventory was then subjected to a rigorous GIS-based analysis, using field-generated datasets on Atlantic salmon ecology in the Nore catchment. The rules-based analysis provided a very substantial re-classification of artificial barriers with a major reduction in the numbers classified as impassable or high-risk. It confirmed that no Ôhigh riskÕ barriers to adult salmon occurred on the R. Nore main stem but identified clusters of high risk barriers in the Dinin subcatchment and a series of moderate risk obstructions in the KingÕs River system. The GIS-based approach enabled an examination of the costs and benefits of stepwise removal of barriers, in terms of additional wetted habitat and salmon spawning area made accessible upstream of each barrier. A multi-species approach was then explored, examining the risk to upstream passage for eel (Anguilla Anguilla L.), sea lamprey (Petromyzon marinus L.) and Twaite shad (Alosa fallax Lace´pede). Substantial clustering of sea lamprey spawning effort was reported downstream of the lowermost weirs on the R. Nore. A combination of barriers identified from a salmon perspective and via the multispecies approach provided a listing of priority barriers for attention. The strategy of step-wise removal or modification of artificial barriers in an upstream direction would provide optimal conservation value for the relevant species. The study identified the primacy of the field survey in geo-referencing site locations. However, it also identified the shortcomings of the qualitative, Ôexpert-judgementÕ approach to risk category allocation of the barriers and, hence, the need for more rigorous criteria in implementing a field-based rapid assessment.

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Aspects of anadromous Allis shad (Alosa alosa Linnaeus) and Twaite shad (Alosa fallax Lacépède) biology in four Irish Special Areas of Conservation (SACs): status, spawning indications and implications for conservation designation

Abstract: Four Special Areas of Conservation (SACs) have been designated in the Republic of Ireland for Twaite shad, Alosa fallax (Lacépède), based on recent historical information on spawning activity-the estuarine reaches of the Rivers Munster Blackwater, Suir,

Cited by 16 publications

References 12 publications

Stock recovery, spawning period and spawning area expansion of the twaite shad Alosa fallax in the Elbe estuary, southern North Sea

Stock recovery, spawning period and spawning area expansion of the twaite shad Alosa fallax in the Elbe estuary, southern North Sea

Variable outcomes of hybridization between declining Alosa alosa and Alosa fallax

Comparison of field- and GIS-based assessments of barriers to Atlantic salmon migration: a case study in the Nore Catchment, Republic of Ireland

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