Behaviour-mediated alteration of positively size-dependent vulnerability to angling in response to historical fishing pressure in a freshwater salmonid

2016 ◽  
Vol 73 (3) ◽  
pp. 461-468 ◽  
Author(s):  
Jun-ichi Tsuboi ◽  
Kentaro Morita ◽  
Thomas Klefoth ◽  
Shinsuke Endou ◽  
Robert Arlinghaus
Keyword(s):  
Field Experiments ◽  
Behavioural Change ◽  
Selective Vulnerability ◽  
Selection Response ◽  
Direct Selection ◽  
Fishing Pressure ◽  
Recreational Fisheries ◽  
Size Dependent ◽  
Amago Salmon ◽  
Stock Assessments

Positively size-selective vulnerability to fishing is well established in recreational fisheries. Size-selective harvesting can either induce an indirect selection response of behavioural traits that are correlated with size or exert direct selection pressures on behaviours that contribute to vulnerability. In addition, learning to avoid future capture may always happen. Behavioural change caused by fishing may in turn affect the size-selective properties of angling. To test this prediction, field experiments with amago salmon (Oncorhynchus masou ishikawae) were conducted. We demonstrated that, as expected, large fish were more vulnerable than smaller individuals in a low fishing pressure (LP) stream and that positively size-selective angling was not (or no longer) present in a high fishing pressure (HP) stream. Moreover, fish in the HP stream were by far less vulnerable to angling with natural bait than fishes in the LP stream. Laboratory studies showed that offspring from HP streams were intrinsically shyer than offspring collected from LP streams. We propose that the increased timidity of individuals inhibiting HP streams disrupted the generally positive relationship among salmon body size and its vulnerability to angling. Fisheries-induced timidity in response to high exploitation rates reduces catchability, affects the size-selective properties of angling, reduces the value of fishery-dependent stock assessments, and potentially affects trophic interactions.

scholarly journals Corrigendum to: Consequences of genetic selection for environmental impact traits on economically important traits in dairy cows

2018 ◽  
Vol 58 (10) ◽  
pp. 1966
Author(s):  
Purna Kandel ◽  
Sylvie Vanderick ◽  
Marie-Laure Vanrobays ◽  
Hélène Soyeurt ◽  
Nicolas Gengler
Keyword(s):  
Dairy Cows ◽  
Body Condition Score ◽  
Genetic Correlations ◽  
Genetic Selection ◽  
Selection Response ◽  
Direct Selection ◽  
Correlated Response ◽  
Production Traits ◽  
Ch4 Emissions ◽  
Natural Logarithm

Methane (CH4) emission is an important environmental trait in dairy cows. Breeding aiming to mitigate CH4 emissions require the estimation of genetic correlations with other economically important traits and the prediction of their selection response. In this study, test-day CH4 emissions were predicted from milk mid-infrared spectra of Holstein cows. Predicted CH4 emissions (PME) and log-transformed CH4 intensity (LMI) computed as the natural logarithm of PME divided by milk yield (MY). Genetic correlations of PME and LMI with traits used currently were approximated from correlations between estimated breeding values of sires. Values were for PME with MY 0.06, fat yield (FY) 0.09, protein yield (PY) 0.13, fertility 0.17; body condition score (BCS) –0.02; udder health (UDH) 0.22; and longevity 0.22. As expected by its definition, values were negative for LMI with production traits (MY –0.61; FY –0.15 and PY –0.40) and positive with fertility (0.36); BCS (0.20); UDH (0.08) and longevity (0.06). The genetic correlations of 33 type traits with PME ranged from –0.12 to 0.25 and for LMI ranged from –0.22 to 0.18. Without selecting PME and LMI (status quo) the relative genetic change through correlated responses of other traits were in PME by 2% and in LMI by –15%, but only due to the correlated response to MY. Results showed for PME that direct selection of this environmental trait would reduce milk carbon foot print but would also affect negatively fertility. Therefore, more profound changes in current indexes will be required than simply adding environmental traits as these traits also affect the expected progress of other traits.

scholarly journals Complex constraints on allometry revealed by artificial selection on the wing of Drosophila melanogaster

2015 ◽  
Vol 112 (43) ◽  
pp. 13284-13289 ◽  
Author(s):  
Geir H. Bolstad ◽  
Jason A. Cassara ◽  
Eladio Márquez ◽  
Thomas F. Hansen ◽  
Kim van der Linde ◽  
...  
Keyword(s):  
Drosophila Melanogaster ◽  
Artificial Selection ◽  
Allometric Scaling ◽  
Power Laws ◽  
Selection Response ◽  
Wing Shape ◽  
Fundamental Aspect ◽  
Direct Selection ◽  
Evolutionary Potential ◽  
Internal Selection

Precise exponential scaling with size is a fundamental aspect of phenotypic variation. These allometric power laws are often invariant across taxa and have long been hypothesized to reflect developmental constraints. Here we test this hypothesis by investigating the evolutionary potential of an allometric scaling relationship in drosophilid wing shape that is nearly invariant across 111 species separated by at least 50 million years of evolution. In only 26 generations of artificial selection in a population of Drosophila melanogaster, we were able to drive the allometric slope to the outer range of those found among the 111 sampled species. This response was rapidly lost when selection was suspended. Only a small proportion of this reversal could be explained by breakup of linkage disequilibrium, and direct selection on wing shape is also unlikely to explain the reversal, because the more divergent wing shapes produced by selection on the allometric intercept did not revert. We hypothesize that the reversal was instead caused by internal selection arising from pleiotropic links to unknown traits. Our results also suggest that the observed selection response in the allometric slope was due to a component expressed late in larval development and that variation in earlier development did not respond to selection. Together, these results are consistent with a role for pleiotropic constraints in explaining the remarkable evolutionary stability of allometric scaling.

Effects of gear type, entrance size and soak time on trap efficiency for freshwater crayfish Cherax destructor and C. albidus

2015 ◽  
Vol 66 (11) ◽  
pp. 989
Author(s):  
Paul Brown ◽  
Taylor L. Hunt ◽  
Khageswor Giri
Keyword(s):  
Field Experiments ◽  
Freshwater Crayfish ◽  
Recreational Fisheries ◽  
Air Breathing ◽  
Fixed Ring ◽  
Cherax Destructor ◽  
Fishing Gears ◽  
Opera House ◽  
By Catch ◽  
Aquatic Mammals

Freshwater crayfish support significant commercial and recreational fisheries worldwide. The genus Cherax is fished in Australia with a variety of fishing gears, yet little is known of the relative efficiency of the different fishing gears and methods. Additionally, freshwater-crayfish traps can pose a risk to air breathing by-catch such as aquatic mammals, reptiles and birds, so by-catch mitigation is important. We sought to understand whether freshwater-crayfish fishing can be undertaken efficiently, using passive traps and nets, without undue risk to air-breathing by-catch species. In field-experiments, we compared the efficiency of six gear types and tested the effect of five exclusion rings on catch performance over three soak times. The efficiency of gear types varied significantly by soak times. In productive locations, catch can be maximised by repeatedly deploying open-topped gear for short soak times. Opera-house traps fitted with fixed entrance rings (45–85-mm diameter) were not size-selective for yabbies. Encouragingly, open-topped gear and opera-house traps fitted with fixed ring entrances much smaller than many commercially available (45-mm diameter) still fish effectively for yabbies. We believe that smaller fixed ring-entrance size is likely to be correlated with a reduced risk of by-catch for air-breathing fauna.

The effects of environmental factors and fisheries management on recreational catches of perch Perca fluviatilis in the Czech Republic

2019 ◽  
Vol 32 ◽  
pp. 15 ◽  
Author(s):  
Roman Lyach ◽  
Jiri Remr
Keyword(s):  
Environmental Factors ◽  
Central Europe ◽  
Fisheries Management ◽  
Perca Fluviatilis ◽  
Fishing Pressure ◽  
Recreational Fisheries ◽  
The Czech Republic ◽  
Perch Perca Fluviatilis ◽  
Average Body ◽  
Average Body Weight

The Eurasian perch Perca fluviatilis is an important fish species in both commercial and recreational fisheries. However, there is concern that perch populations in Central Europe are decreasing. This study aimed to assess the effects of environmental factors and management on recreational perch catches. Data from individual angling logbooks collected by the Czech Fishing Union on 229 fishing grounds during the period 2005–2016 were used in this study. In total, almost 60 000 perch weighing 17 500 kg were recorded. During the study period, total perch catches decreased by 60%, catch per fishing visit decreased by 70%, average body weight of caught perch increased by 18%, and percentage of fishing grounds with perch catches decreased by 13%. The results indicated that the decreasing catches were due to increasing fishing pressure. Further, fishing grounds with higher fishing visit rates had higher catches in general but lower catch per fishing visit. Larger and more productive rivers also showed higher catches. In contrast, the intensity of fish stocking did not affect catches. In conclusion, perch populations in Central Europe are likely under high fishing pressure, and the pressure is further increasing.

scholarly journals Heritability, Genetic and Phenotypic Correlations, and Predicted Selection Response of Quantitative Traits in Peach: I. An Analysis of Several Reproductive Traits

1998 ◽  
Vol 123 (4) ◽  
pp. 598-603 ◽  
Author(s):  
Valdomiro A.B. de Souza ◽  
David H. Byrne ◽  
Jeremy F. Taylor
Keyword(s):  
Fixed Effects ◽  
Prunus Persica ◽  
Fruit Set ◽  
Genetic Correlations ◽  
Selection Response ◽  
Direct Selection ◽  
Multiple Trait ◽  
Narrow Sense Heritability ◽  
Phenotypic Correlations ◽  
Flower Density

Seedlings of 108 families from crosses among 42 peach [Prunus persica (L.) Batsch] cultivars and selections were evaluated for six plant characteristics in 1993, 1994, and 1995. The data were analyzed by using a mixed linear model, with years treated as fixed and additive genotypes as random factors. Best linear unbiased prediction (BLUP) was used to estimate fixed effects. Restricted maximum likelihood (REML) was used to estimate variance components, and a multiple trait model was used to estimate genetic and phenotypic covariances among traits. The narrow-sense heritability estimates were 0.41, 0.29, 0.48, 0.47, 0.43, and 0.23 for flower density, flowers per node, node density, fruit density, fruit set, and blind node propensity, respectively. Most genetic correlations among pairs of traits were ≥0.30 and were, in general, much higher than the corresponding phenotypic correlations. Flower density and flowers per node (ra = 0.95), fruit density and fruit set (ra = 0.84) and flower density and fruit density (ra = 0.71) were the combinations of traits that had the highest genetic correlation estimates. Direct selection practiced solely for flower density (either direction) is expected to have a greater effect on fruit density than direct selection for fruit density.

scholarly journals 215 Selection response for meat quality and carcass composition in commercial pigs using crossbred and purebred traits as predictors

2019 ◽  
Vol 97 (Supplement_3) ◽  
pp. 45-45
Author(s):  
Emmanuel A Lozada-Soto ◽  
Justin Fix ◽  
Clint Schwab ◽  
Francesco Tiezzi
Keyword(s):  
Meat Quality ◽  
Lower Cost ◽  
Economic Value ◽  
Cost Effective ◽  
Selection Response ◽  
Carcass Composition ◽  
Direct Selection ◽  
Selection Indices ◽  
Breeding Objectives ◽  
Selection For

Abstract Meat quality (MQ) and carcass composition (CC) are traits with high economic value, but their phenotyping costs makes direct selection for these traits economically unsustainable. Evaluation of traits with lower cost of collection in crossbred (CB) and purebred (PB) animals for use in selection for MQ and CC remains limited. The aim of this study was to measure the response to selection of economically important MQ and CC traits using different selection indices built on cost-effective correlated traits. Phenotypic and genomic information (using 60K SNP chips) was collected for three-way CB (n = 1227 to 5117 phenotyped, n = 1252 genotyped) and PB (n = 3,251 phenotyped, n = 1035 genotyped) Duroc animals belonging to 28 paternal half-sib families. The three breeding objectives (for which response was estimated) were intramuscular fat (IMF), slice shear force (SSF), and loin weight (LW). In total 7 different selection indices (A-G) were used to estimate the selection response for each breeding objective (Table 1). Heritability and genetic correlation parameters for all traits were estimated using GIBBS1F90. Selection response was obtained as expected response per generation weighed by the accuracy of breeding values estimated from a 4-fold cross validation, where animals were grouped based on sire relatedness. For all three breeding objectives, the index which provided best selection response was A (direct selection), with values of 0.35%, -0.72 kg, and 0.85 kg for IMF, SSF, and LW respectively. The index which provided the second-best selection response was B (color and pH traits) for all three breeding objectives, with values of 0.15%, -0.26kg, and 0.30kg for IMF, SSF, and LW respectively. Results for selection response using indices C-G can be found in Table 1. In the absence of direct selection due to high costs of phenotyping, respectable selection response can be achieved by indirect selection using traits with lower cost of collection.

Life in the Slow Lane: Ecology and Conservation of Long-Lived Marine Animals

1999 ◽  
Keyword(s):  
Life History ◽  
Management Plan ◽  
Fishing Effort ◽  
Life History Strategies ◽  
Shark Species ◽  
Fishing Pressure ◽  
Marine Animals ◽  
Selective Pressures ◽  
Stock Assessments ◽  
History Of

<em> Abstract.</em>—Sharks have the reputation of being particularly vulnerable to fishing pressure, a fact attributed to their generally ‘<EM> K</EM>-selected’ life history strategies. The history of shark fisheries is not encouraging, and their poor record of sustainability is compounded by the fact that few countries have any form of management for these resources. The Australian Southern Shark Fishery provides an example of a well-studied shark fishery with a long history of exploitation that has been under a management plan for some ten years. This fishery is unique in that it exploits, under a similar fishing regime, two similar target shark species that show very different responses to fishing pressure. Stock assessments suggest that under current fishing effort the catch of one species is sustainable while the other species is overexploited. The vulnerability of the two species to the fishing gear is similar but their biological productivity is very different. The selective pressures that may have given rise to these different life history strategies are discussed.

scholarly journals Effectiveness of selection, parent-offspring correlation and regression in bacterial blight resistance genes introgressed rice segregating population

2017 ◽  
Vol 47 (9) ◽  
Author(s):  
Ponnaiah Govintharaj ◽  
Shalini Tannidi ◽  
Manonmani Swaminathan ◽  
Robin Sabariappan
Keyword(s):  
Resistance Genes ◽  
Bacterial Blight ◽  
Crop Improvement ◽  
Selection Response ◽  
Direct Selection ◽  
Blight Resistance ◽  
Bacterial Blight Resistance ◽  
Improvement Program ◽  
Early Generation ◽  
Program Selection

ABSTRACT: The effectiveness of early generation selection was practiced in bacterial blight resistance genes introgressed F2 and F2:3 population of the cross CB 174 R × IRBB 60 in rice. F2 Selection have been proved to be robust and effective tool in crop improvement program. Selection differential was positive for all studied traits. Selection response was high for number of grains, thus indicating the effectiveness of selection for these character. Realized heritability was found high for number of grains and thousand grain weight, suggested that direct selection was effective. Expected selection response and predicted genetic gain was high for number of grains. Parent-offspring correlation showed low but significance association for number of productive tillers (r=0.47**, P<0.01), single plant yield (r=0.35**, P<0.01) and (r=0.30*, P<0.05) panicle length in F2 and F2:3 generation indicates that selection was fruitful in early generation. Statistically regression coefficient was not significant linear dependence of the mean of F2 and F2:3 generation.

scholarly journals Consequences of genetic selection for environmental impact traits on economically important traits in dairy cows

2018 ◽  
Vol 58 (10) ◽  
pp. 1779
Author(s):  
Purna Kandel ◽  
Sylvie Vanderick ◽  
Marie-Laure Vanrobays ◽  
Hélène Soyeurt ◽  
Nicolas Gengler
Keyword(s):  
Dairy Cows ◽  
Body Condition Score ◽  
Genetic Correlations ◽  
Genetic Selection ◽  
Selection Response ◽  
Direct Selection ◽  
Correlated Response ◽  
Production Traits ◽  
Ch4 Emissions ◽  
Natural Logarithm

Methane (CH4) emission is an important environmental trait in dairy cows. Breeding aiming to mitigate CH4 emissions require the estimation of genetic correlations with other economically important traits and the prediction of their selection response. In this study, test-day CH4 emissions were predicted from milk mid-infrared spectra of Holstein cows. Predicted CH4 emissions (PME) and log-transformed CH4 intensity (LMI) computed as the natural logarithm of PME divided by milk yield (MY). Genetic correlations of PME and LMI with traits used currently were approximated from correlations between estimated breeding values of sires. Values were for PME with MY 0.06, fat yield (FY) 0.09, protein yield (PY) 0.13, fertility 0.17; body condition score (BCS) –0.02; udder health (UDH) 0.22; and longevity 0.22. As expected by its definition, values were negative for LMI with production traits (MY –0.61; FY –0.15 and PY –0.40) and positive with fertility (0.36); BCS (0.20); UDH (0.08) and longevity (0.06). The genetic correlations of 33 type traits with PME ranged from –0.12 to 0.25 and for LMI ranged from –0.22 to 0.18. Without selecting PME and LMI (status quo) the relative genetic change through correlated responses of other traits were in PME by 2% and in LMI by –15%, but only due to the correlated response to MY. Results showed for PME that direct selection of this environmental trait would reduce milk carbon foot print but would also affect negatively fertility. Therefore, more profound changes in current indexes will be required than simply adding environmental traits as these traits also affect the expected progress of other traits.

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