scholarly journals Genetic identification of farmed and wild Atlantic cod, Gadus morhua, in coastal Norway

2011 ◽  
Vol 68 (5) ◽  
pp. 901-910 ◽  
Author(s):  
Kevin A. Glover ◽  
Geir Dahle ◽  
Knut E. Jørstad
Keyword(s):  
Case Studies ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Genetic Interactions ◽  
Genetic Identification ◽  
Fish Farms ◽  
Multiple Sources ◽  
Farmed Fish ◽  
Farmed Escapees

Abstract Glover, K. A., Dahle, G., and Jørstad, K. E. 2011. Genetic identification of farmed and wild Atlantic cod, Gadus morhua, in coastal Norway. – ICES Journal of Marine Science, 68: 901–910. Each year thousands of Atlantic cod escape from Norwegian fish farms. To investigate the potential for the genetic identification of farmed–escaped cod in the wild, three case studies were examined. Samples of farmed, recaptured farmed escapees, and wild cod were screened for ten microsatellite loci and the Pan I locus. Variable genetic differences were observed among cod sampled from different farms and cages (pairwise FST = 0.0–0.1), and in two of the case studies, the most likely farm(s) of origin for most of the recaptured escapees were identified. In case study 2, wild cod were genetically distinct from both farmed fish (pairwise FST = 0.026–0.06) and recaptured farmed–escaped cod (pairwise FST = 0.029 and 0.039), demonstrating the potential to detect genetic interactions in that fjord. Genetic identification of escapees was more challenging in case study 3, and some morphologically characterized wild cod were found to most likely represent farmed escapees. It is concluded that where cod are farmed in the same region as their own parents/grandparents were initially sourced, or where farmed escapees originate from multiple sources, quantifying genetic interactions with wild populations will be challenging with neutral or nearly neutral markers such as microsatellites.

Intergenerational valuation of fisheries resources can justify long-term conservation: a case study in Atlantic cod (Gadus morhua)

2005 ◽  
Vol 62 (5) ◽  
pp. 1104-1110 ◽  
Author(s):  
C H Ainsworth ◽  
U R Sumaila
Keyword(s):  
Discount Rate ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Ecosystem Model ◽  
Conventional Model ◽  
Fisheries Resources ◽  
Optimal Harvest ◽  
Harvest Policies

Where the conventional model of discounting advocates aggressive harvest policies, intergenerational discounting could have been used to render the historic gross overfishing of Atlantic cod (Gadus morhua) economically unappealing compared with a more conservative long-term strategy. Under these discounting approaches, we compare the historic harvest trend from 1985 (and projected postcollapse earnings) with theoretical optimal harvest profiles determined by an ecosystem model. The optimal scenarios generate less initial harvest than the historic profile but maintain the resource and provide greater yields over the long term. At a discount rate equal to market interest, we demonstrate that it was more economic under conventional valuation to harvest the cod stock to collapse than it would have been to sustain the population. However, under intergenerational valuation, the sustainable optimal scenarios outperform the actual harvest profile. Application of conventional discounting by fishing consortiums may be partly to blame for depletion, yet management fell short of even that ideal.

Reproductive interactions between fugitive farmed and wild Atlantic cod (Gadus morhua) in the field

2010 ◽  
Vol 67 (8) ◽  
pp. 1221-1231 ◽  
Author(s):  
Justin J. Meager ◽  
Jon Egil Skjæraasen ◽  
Anders Fernö ◽  
Svein Løkkeborg
Keyword(s):  
Mating System ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
Spatial Dynamics ◽  
Wild Fish ◽  
Spawning Ground ◽  
Males And Females ◽  
Farmed Escapees ◽  
Ultrasonic Transmitters

Atlantic cod ( Gadus morhua ) are being increasingly farmed in net pens adjacent to coastal populations that are currently at historic lows. One concern is that farmed escapees enter local spawning shoals and mate with wild cod. We tested for the potential of escaped farmed cod to interact and hybridize with wild fish by examining the spatial dynamics of, and associations between, fish tagged with ultrasonic transmitters. Based on these data, we also investigated the basic mating system of cod in the field. The spawning ground was best described as a lekking arena. Wild males aggregated near the seafloor and associations between individuals were frequent. Wild females had a pelagic and dispersed distribution and rarely associated with each other. Associations between individual wild males and females were also infrequent. Farmed males rarely associated with wild fish and had core usage areas above the wild males, suggesting that they were not admitted into the spawning arena. Farmed females were over the spawning arena more frequently than wild females and often associated with wild males at the depth of the spawning arena, indicating potential mating with wild males and the possibility of courtship interference. Hence, hybridization between escaped farmed and wild cod is likely.

scholarly journals Recolonization history and large-scale dispersal in the open sea: the case study of the North Atlantic cod, Gadus morhua L.

2008 ◽  
Vol 94 (2) ◽  
pp. 315-329 ◽  
Author(s):  
CHRISTOPHE PAMPOULIE ◽  
MAGNÚS ÖRN STEFÁNSSON ◽  
THÓRA DÖGG JÖRUNDSDÓTTIR ◽  
BRET S. DANILOWICZ ◽  
ANNA KRISTÍN DANÍELSDÓTTIR
Keyword(s):  
North Atlantic ◽  
Large Scale ◽  
Gadus Morhua ◽  
Atlantic Cod ◽  
The North ◽  
Open Sea ◽  
The North Atlantic

Benchmarking growth of farmed Atlantic cod, Gadus morhua: a case study in Ireland

2011 ◽  
Vol 43 (5) ◽  
pp. 670-678 ◽  
Author(s):  
Majbritt Bolton-Warberg ◽  
Richard D FitzGerald
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod

scholarly journals Transformational change in healthcare: an examination of four case studies

2016 ◽  
Vol 40 (2) ◽  
pp. 163 ◽  
Author(s):  
Kate Charlesworth ◽  
Maggie Jamieson ◽  
Rachel Davey ◽  
Colin D. Butler
Keyword(s):  
Performance Management ◽  
Case Studies ◽  
Transformational Change ◽  
Key Factors ◽  
Multiple Sources ◽  
Health And Social Care ◽  
The World ◽  
Care Systems ◽  
Healthcare Leaders

Objectives Healthcare leaders around the world are calling for radical, transformational change of our health and care systems. This will be a difficult and complex task. In this article, we examine case studies in which transformational change has been achieved, and seek to learn from these experiences. Methods We used the case study method to investigate examples of transformational change in healthcare. The case studies were identified from preliminary doctoral research into the transition towards future sustainable health and social care systems. Evidence was collected from multiple sources, key features of each case study were displayed in a matrix and thematic analysis was conducted. The results are presented in narrative form. Results Four case studies were selected: two from the US, one from Australia and one from the UK. The notable features are discussed for each case study. There were many common factors: a well communicated vision, innovative redesign, extensive consultation and engagement with staff and patients, performance management, automated information management and high-quality leadership. Conclusions Although there were some notable differences between the case studies, overall the characteristics of success were similar and collectively provide a blueprint for transformational change in healthcare. What is known about the topic? Healthcare leaders around the world are calling for radical redesign of our systems in order to meet the challenges of modern society. What does this paper add? There are some remarkable examples of transformational change in healthcare. The key factors in success are similar across the case studies. What are the implications for practitioners? Collectively, these key factors can guide future attempts at transformational change in healthcare.

scholarly journals Post-escape dispersal of juvenile Atlantic cod Gadus morhua from Norwegian fish farms and their potential for recapture

2013 ◽  
Vol 3 (2) ◽  
pp. 107-116 ◽  
Author(s):  
RM Serra-Llinares ◽  
R Nilsen ◽  
I Uglem ◽  
P Arechavala-Lopez ◽  
PA Bjørn ◽  
...  
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Fish Farms

scholarly journals The expression of secondary sexual characteristics in recruit- and repeat-spawning farmed and wild Atlantic cod (Gadus morhua)

2008 ◽  
Vol 65 (9) ◽  
pp. 1710-1716 ◽  
Author(s):  
Jon Egil Skjæraasen ◽  
Justin J. Meager ◽  
Ørjan Karlsen
Keyword(s):  
Gadus Morhua ◽  
Atlantic Cod ◽  
Mating Behaviour ◽  
Secondary Sexual Characteristics ◽  
Sexual Characteristics ◽  
In The Wild ◽  
Defensive Behaviours ◽  
Farmed Escapees ◽  
Pelvic Fin ◽  
Secondary Sexual

Abstract Skjæraasen, J. E., Meager, J. J., and Karlsen, Ø. 2008. The expression of secondary sexual characteristics in recruit- and repeat-spawning farmed and wild Atlantic cod (Gadus morhua). – ICES Journal of Marine Science, 65: 1710–1716. We examined the expression of the two known secondary sexual characteristics of Atlantic cod, the pelvic fin and the drumming muscle, in farmed and wild cod stemming from the same population. Farmed and wild males had longer pelvic fins and larger drumming muscles than females, but wild cod had longer fins than farmed cod. The size of the drumming muscle of males was similar among wild and farmed cod, but farmed females had smaller muscles than their wild counterparts. Repeat-spawning wild males tended to invest less in drumming-muscle mass and more in pelvic-fin growth than recruit-spawning fish, whereas the reverse was true for farmed males. Males use pelvic fins to embrace females during ventral mounts, a key mating behaviour, and display them to other males during agonistic interactions. The drumming muscle is used by males to produce sound during courtship and aggressive displays, whereas females only use sound outside the spawning season, for agonistic and defensive behaviours that are unlikely to be as important in the farming environment. The results are discussed in the context of the reproductive success of farmed escapees in the wild.

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