Loughs Agency

Victoria Road, United Kingdom

Loughs Agency

Victoria Road, United Kingdom
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Dauphin G.,French National Institute for Agricultural Research | Dauphin G.,University of Glasgow | Dauphin G.,Loughs Agency | Prevost E.,French National Institute for Agricultural Research | And 3 more authors.
Fisheries Research | Year: 2010

Redd (nest) counts are widely used for monitoring salmonid populations. Because of their relative low cost, redd counts allow a good spatial coverage over a long period of time. In this paper we develop a generic Bayesian hierarchical model relating Atlantic salmon, Salmo salar L. spawner abundance and redd counts which accounts for the associated sources of uncertainty. Three rivers of a large catchment are considered and variability across these rivers in the spawners to redds relationship is taken in account. We use short time series, where data on both redds and spawner numbers are available to estimate the parameters of the relationship. We then use the same relationship to estimate spawner abundances for a longer time series with only redd counts available. It is concluded from this exercise that redd counts can be a valuable source of information for monitoring spawning abundances of salmonids and should not be dismissed a priori. However, the uncertainty of spawner abundance estimates derived from redd count data alone may be large and therefore must be assessed. Ancillary data informing the redd counting process can provide great improvements in the precision of the abundance estimates. © 2010 Elsevier B.V.


Ensing D.,Agri Food and Biosciences Institute of Northern Ireland | Crozier W.W.,Agri Food and Biosciences Institute of Northern Ireland | Boylan P.,Loughs Agency | O'Maoileidigh N.,Marine Institute of Ireland | Mcginnity P.,University College Cork
Journal of Fish Biology | Year: 2013

A genetic stock identification (GSI) study was undertaken in a fishery for Atlantic salmon Salmo salar to determine the effects of restrictive fishery management measures on the stock composition of the fishery, and if accurate and precise stock composition estimates could be achieved on the small geographical scale where this fishery operates, using a suite of only seven microsatellite loci. The stock composition of the Foyle fishery was shown to comprise almost exclusively of Foyle origin fish in the 3 years after restrictive measures were introduced in 2007, compared to 85% the year before. This showed that the restrictive measures resulted in the Foyle fishery being transformed from a mixed-stock fishery to an almost exclusively single-stock fishery, and showed how GSI studies can guide and evaluate management decisions to successfully manage these fisheries. Highly accurate and precise stock composition estimates were achieved in this study, using both cBAYES and ONCOR genetic software packages. This suggests accurate and precise stock composition is possible even on small geographical scales. © 2013 AFBINI Journal of Fish Biology © 2013 The Fisheries Society of the British Isles.


Ensing D.,Agri Food and Biosciences Institute of Northern Ireland | Prodohl P.A.,Queen's University of Belfast | McGinnity P.,University College Cork | Boylan P.,Loughs Agency | And 2 more authors.
Ecology and Evolution | Year: 2011

Little is known about the microevolutionary processes shaping within river population genetic structure of aquatic organisms characterized by high levels of homing and spawning site fidelity. Using a microsatellite panel, we observed complex and highly significant levels of intrariver population genetic substructure and Isolationby-Distance, in the Atlantic salmon stock of a large river system. Two evolutionary models have been considered explaining mechanisms promoting genetic substructuring in Atlantic salmon, the member-vagrant and metapopulation models. We show that both models can be simultaneously used to explain patterns and levels of population structuringwithin the Foyle system. We showthat anthropogenic factors have had a large influence on contemporary population structure observed. In an analytical development, we found that the frequently used estimator of genetic differentiation, ST, routinely underestimated genetic differentiation by a factor three to four compared to the equivalent statistic Jost's Dest (Jost 2008). These statistics also showed a near-perfect correlation. Despite ongoing discussions regarding the usefulness of "adjusted" FST statistics, we argue that these could be useful to identify and quantify qualitative differences between populations, which are important from management and conservation perspectives as an indicator of existence of biologically significant variation among tributary populations or a warning of critical environmental damage. © 2011 The Authors. Ecology and Evolution published by Blackwell Publishing Ltd.


Barry J.,University of Glasgow | Newton M.,University of Glasgow | Dodd J.A.,University of Glasgow | Hooker O.E.,University of Glasgow | And 3 more authors.
Hydrobiologia | Year: 2016

A fixed receiver array was used to examine the movement patterns and space use of the European eel Anguilla anguilla in an oligotrophic Irish lake between July and September. We assessed home range size, temporal change in spatial behaviour and activity patterns of broad-headed (n = 11) and narrow-headed (n = 8) morphotypes. Broad-headed individuals displayed a larger home range (mean KUD95 (km2):0.296 ± 0.04 S.E.) in comparison to narrow-headed individuals (mean KUD95 (km2):0.143 ± 0.02 S.E.). Eel activity was strongly dependent on light conditions. Narrow-headed individuals’ movement peaks occurred at dawn and dusk in comparison to broad-headed individuals which exhibited a more stable movement pattern throughout night and into dawn, suggesting that narrow-headed eels are more crepuscular in nature whereas broad-headed individuals are more nocturnal. Lunar phase period also influenced eel movement within the lake. These results provide valuable insights into the spatio-temporal distribution of yellow eels in a lake system, demonstrating that individuality in foraging behaviour has direct influence on spatial patterns. © 2015, Springer International Publishing Switzerland.


Newton M.,University of Glasgow | Barry J.,University of Glasgow | Dodd J.A.,University of Glasgow | Lucas M.C.,Durham University | And 2 more authors.
Journal of Fish Biology | Year: 2016

Mortality rates of wild Atlantic salmon Salmo salar smolts implanted with acoustic transmitters were assessed to determine if mortality was size dependent. The routinely accepted, but widely debated, ‘2% transmitter mass: body mass’ rule in biotelemetry was tested by extending the transmitter burden up to 12·7% of body mass in small [mean fork length (LF) 138·3 mm, range 115–168 mm] downstream migrating S. salar smolts. Over the short timescale of emigration (range 11·9–44·5 days) through the lower river and estuary, mortality was not related to S. salar size, nor was a relationship found between mortality probability and transmitter mass: body mass or transmitter length: LF ratios. This study provides further evidence that smolt migration studies can deviate from the ‘2% rule’ of thumb, to more appropriate study-specific measures, which enables the use of fishes representative of the body size in natural populations without undue effects. © 2016 The Fisheries Society of the British Isles


Barry J.,University of Glasgow | Newton M.,University of Glasgow | Dodd J.A.,University of Glasgow | Lucas M.C.,Durham University | And 2 more authors.
Journal of Fish Biology | Year: 2016

The unimpeded downstream movement patterns and migration success of small female and male Anguilla anguilla through a catchment in north-west Europe were studied using an acoustic hydrophone array along the River Finn and into the Foyle Estuary in Ireland. Twenty silver-stage A. anguilla (total length, LT, range: 332-520 mm) were trapped 152 km upstream from a coastal marine sea-lough outlet and internally tagged with acoustic transmitters of which 19 initiated downstream migration. Migration speed was highly influenced by river flow within the freshwater (FW) compartment. Anguilla anguilla activity patterns were correlated with environmental influences; light, tidal direction and lunar phase all influenced the initiation of migration of tagged individuals. Migration speed varied significantly between upstream and lower river compartments. Individuals migrated at a slower speed in transitional water and sea-lough compartments compared with the FW compartment. While 88·5% survival was recorded during migration through the upper 121 km of the river and estuary, only 26% of A. anguilla which initiated downstream migration were detected at the outermost end of the acoustic array. Telemetry equipment functioned efficiently, including in the sea-lough, so this suggests high levels of mortality during sea-lough migration, or less likely, long-term sea-lough residence by silver A. anguilla emigrants. This has important implications for eel management plans. © 2016 The Fisheries Society of the British Isles.


PubMed | Loughs Agency, Durham University and University of Glasgow
Type: Journal Article | Journal: Journal of fish biology | Year: 2016

The unimpeded downstream movement patterns and migration success of small female and male Anguilla anguilla through a catchment in north-west Europe were studied using an acoustic hydrophone array along the River Finn and into the Foyle Estuary in Ireland. Twenty silver-stage A. anguilla (total length, LT , range: 332-520 mm) were trapped 152 km upstream from a coastal marine sea-lough outlet and internally tagged with acoustic transmitters of which 19 initiated downstream migration. Migration speed was highly influenced by river flow within the freshwater (FW) compartment. Anguilla anguilla activity patterns were correlated with environmental influences; light, tidal direction and lunar phase all influenced the initiation of migration of tagged individuals. Migration speed varied significantly between upstream and lower river compartments. Individuals migrated at a slower speed in transitional water and sea-lough compartments compared with the FW compartment. While 885% survival was recorded during migration through the upper 121 km of the river and estuary, only 26% of A. anguilla which initiated downstream migration were detected at the outermost end of the acoustic array. Telemetry equipment functioned efficiently, including in the sea-lough, so this suggests high levels of mortality during sea-lough migration, or less likely, long-term sea-lough residence by silver A. anguilla emigrants. This has important implications for eel management plans.


Barry J.,University of Glasgow | Bodles K.J.,Queen's University of Belfast | Boylan P.,Loughs Agency | Adams C.E.,University of Glasgow
Biology and Environment | Year: 2015

This study presents evidence of the decline in European eel abundance in a transitional water body in the Northern Ireland from 1967-2013. The available historical data is from an important period, representative of the baseline abundance of eels in a transitional water body before recruitment collapse. The results from this study indicate the current eel population in the Foyle estuary is 3.38% of historical levels. © ROYAL IRISH ACADEMY.


Bromley C.,Queen's University of Belfast | McGonigle C.,Loughs Agency | Ashton E.C.,Queen's University of Belfast | Roberts D.,Queen's University of Belfast
Ocean and Coastal Management | Year: 2016

The study was aimed at learning lessons from historical translocations of the European native oyster, Ostrea edulis and contributing to the debate on best practice for restoration projects. An extensive literature review of over 100 documents spanning 200 years was conducted to look at translocations of Ostrea edulis and investigate temperature related reproduction. Differences among geographical locations were assessed by multivariate analysis of reproductive data. Translocations of hundreds to millions of Ostrea edulis have taken place over the past 200 years, mainly for commercial purposes. Movements were either single actions or regular events over many years. Whilst 75 separate records of Ostrea edulis movements from within European waters were documented, it is likely that many more took place. Introductions have also been made outside Europe for aquaculture; translocations back to European waters, have led to the introduction of pathogens. The timing and duration of reproductive periods and spawning temperature thresholds of Ostrea edulis in the middle region of its distribution range were similar. Cluster analysis of documented periods of reproduction indicated that introduced and restocked populations clustered with their putative donor populations. Whilst the Irish production areas clustered together, reproductive cycles in Lough Foyle in the northwest of the island of Ireland showed greater similarity to the now extinct deeper water English Channel beds. Historically, the ability of oysters to breed after translocation was not considered important. Successful reproduction and recruitment is however fundamental to conserving the species. Where translocation of stock is used to restore Ostrea edulis in areas where it has been extirpated, this study suggests that restocking should be at high densities and carried out over several years and that harvesting should be restricted to increase the chances of establishing self-sustaining populations. © 2016 Elsevier Ltd.


Bromley C.,Queen's University of Belfast | McGonigle C.,Loughs Agency | Ashton E.C.,Queen's University of Belfast | Roberts D.,Queen's University of Belfast
Hydrobiologia | Year: 2016

Habitat degradation is a contributory factor to poor recruitment and sustainability of the European native oyster, Ostrea edulis. Bed cleaning (harrowing) is a widely referenced but little studied habitat management measure aimed at exposing clean shell for oyster larvae to settle upon. This study carried out a large-scale field experiment in Lough Foyle on the border of Northern Ireland and Ireland over 3 years aimed at investigating the effects of harrowing on oyster spat settlement, substratum condition, suspended particulate matter and associated faunal assemblage. The results demonstrated that O. edulis spat settlement was higher in unharrowed areas and there was no significant difference in bivalve settlement between the two treatments. Harrowing had no significant effect on percentage cover of fouling organisms, but there was a significant difference between assemblages in harrowed and unharrowed treatments. This study concluded that harrowing is not suitable for all oyster production areas and should only be employed with caution. © 2015, The Author(s).

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