Variability in size and age at maturity in the marine scavengerBuccinanops globulosus(Gastropoda: Nassariidae) from Patagonia

2015 ◽  
Vol 95 (6) ◽  
pp. 1193-1201 ◽  
Author(s):  
María Soledad Avaca ◽  
Pablo Martín ◽  
Maite Narvarte
Keyword(s):  
Growth Rates ◽  
Fishery Management ◽  
Reproductive Effort ◽  
Reaction Norm ◽  
Logistic Function ◽  
Rate Variation ◽  
Female Size ◽  
Age At Maturity ◽  
Management Actions ◽  
Minimum Landing Size

Growth rates and size-age at maturity are life history traits that combine in different ways to achieve maximal fitness. The marine scavengerBuccinanops globulosuswas used as a model to explore the variation on female size-age at maturity and reproductive effort among three populations characterized by different growth rates (slow, moderate and rapid). This species constitutes the target of an artisanal fishery in North Patagonia. Here, a suite of different estimators of size-age at maturity derived from gonad histological analysis and the study of females carrying egg capsules were obtained. Data were modelled using a logistic function and the maturity patterns were compared among populations. We found that female size and age at maturity were variable and site-specific. The fastest-growing population showed the lowest reproductive effort. Slow and rapid-growing females mature at different sizes but at the same age whereas moderate-growing females mature both at a different size and age (intermediate size and at earlier age). Thus, results obtained here are difficult to reconcile with a single reaction norm for a single genotype in the studied populations. Growth rate variation is not enough to explain the patterns described here. The information provided could be used for the establishment of fishery management actions, such as minimum landing size.

scholarly journals Genotyping of Two Mediterranean Trout Populations in Central-Southern Italy for Conservation Purposes Using a Rainbow-Trout-Derived SNP Array

Animals ◽  
2021 ◽  
Vol 11 (6) ◽  
pp. 1803
Author(s):  
Valentino Palombo ◽  
Elena De Zio ◽  
Giovanna Salvatore ◽  
Stefano Esposito ◽  
Nicolaia Iaffaldano ◽  
...  
Keyword(s):  
Rainbow Trout ◽  
Genetic Structure ◽  
Fishery Management ◽  
Snp Array ◽  
Fine Scale ◽  
Principal Coordinates Analysis ◽  
Data Set ◽  
Management Actions ◽  
Principal Coordinates ◽  
Mediterranean Trout

Mediterranean trout is a freshwater fish of particular interest with economic significance for fishery management, aquaculture and conservation biology. Unfortunately, native trout populations’ abundance is significantly threatened by anthropogenic disturbance. The introduction of commercial hatchery strains for recreation activities has compromised the genetic integrity status of native populations. This work assessed the fine-scale genetic structure of Mediterranean trout in the two main rivers of Molise region (Italy) to support conservation actions. In total, 288 specimens were caught in 28 different sites (14 per basins) and genotyped using the Affymetrix 57 K rainbow-trout-derived SNP array. Population differentiation was analyzed using pairwise weighted FST and overall F-statistic estimated by locus-by-locus analysis of molecular variance. Furthermore, an SNP data set was processed through principal coordinates analysis, discriminant analysis of principal components and admixture Bayesian clustering analysis. Firstly, our results demonstrated that rainbow trout SNP array can be successfully used for Mediterranean trout genotyping. In fact, despite an overwhelming number of loci that resulted as monomorphic in our populations, it must be emphasized that the resulted number of polymorphic loci (i.e., ~900 SNPs) has been sufficient to reveal a fine-scale genetic structure in the investigated populations, which is useful in supporting conservation and management actions. In particular, our findings allowed us to select candidate sites for the collection of adults, needed for the production of genetically pure juvenile trout, and sites to carry out the eradication of alien trout and successive re-introduction of native trout.

scholarly journals Epidemic Growth Rates and Host Movement Patterns Shape Management Performance for Pathogen Spillover at The Wildlife-livestock Interface

2019 ◽  
Author(s):  
Kezia R. Manlove ◽  
Laura M. Sampson ◽  
Benny Borremans ◽  
E. Frances Cassirer ◽  
Ryan S. Miller ◽  
...  
Keyword(s):  
Growth Rates ◽  
Life Histories ◽  
Animal Health ◽  
Movement Patterns ◽  
Health Food ◽  
Management Options ◽  
Management Performance ◽  
Fast Growing ◽  
Management Actions ◽  
Host Movement

ABSTRACTManaging pathogen spillover at the wildlife-livestock interface is a key step toward improving global animal health, food security, and wildlife conservation. However, predicting the effectiveness of management actions across host-pathogen systems with different life histories is an on-going challenge since data on intervention effectiveness are expensive to collect and results are system-specific. We developed a simulation model to explore how the efficacies of different management strategies vary according to host movement patterns and epidemic growth rates. The model suggested that fast-growing, fast-moving epidemics like avian influenza were best-managed with actions like biosecurity or containment, which limited and localized overall spillover risk. For fast-growing, slower-moving diseases like foot-and-mouth disease, depopulation or prophylactic vaccination were competitive management options. Many actions performed competitively when epidemics grew slowly and host movements were limited, and how management efficacy related to epidemic growth rate or host movement propensity depended on what objective was used to evaluate management performance. This framework may be a useful step in advancing how we classify and prioritise responses to novel pathogen spillover threats, and evaluate current management actions for pathogens emerging at the wildlife-livestock interface.

scholarly journals Evaluation on Minimum Landing Size Regulations in Turkish Marine Fisheries from Scientific Perspective

2019 ◽  
Vol 7 (sp1) ◽  
pp. 27
Author(s):  
Ozan Soykan
Keyword(s):  
Regional Differences ◽  
Fishery Management ◽  
Marine Species ◽  
Require Result ◽  
Marine Fishery ◽  
Minimum Landing Size ◽  
Fisheries Regulation ◽  
The Republic ◽  
Scientific Results ◽  
Republic Of Turkey

Crucial point of fishery management is to let the fish or other species reproduce at least once during their life. Therefore it is very important to determine the length at maturity (Lm) for given species before the first capture. Focus of this study is to determine the consistency between scientific results and minimum landing size (MLS) regulations in the marine fishery of Turkey. For this purpose, 4/1 communique on commercial fishery (2016/35) published by the Republic of Turkey Ministry of Agriculture and Forestry was investigated in order to expose the MLS of given species in Turkey. Literature survey on Lm was also conducted preferably on studies which were performed in Turkish waters or from the Mediterranean basin in order to avoid regional differences. While 86 marine species were reported to be landed in the official fishery statistics, only 49 of them were appointed with a MLS in the commercial fisheries regulation. It was determined that MLS of 27 species were below the Lm according to the selected literature, 7 of them require result on Lm, status of the 2 species couldn’t be decided due to different length types and 13 (27% of the decisions on MLS) of them were found to be in accordance with the scientific literature on Lm. This study shows that MLS regulation must be revised for most of the species in the surrounding waters of Turkey and comprehensive maturity studies are urgently needed in order to fulfill the scientific gap.

scholarly journals The reaction norm of size and age at maturity under multiple predator risk

2010 ◽  
Vol 79 (5) ◽  
pp. 1069-1076 ◽  
Author(s):  
Andrew P. Beckerman ◽  
Gwendolene M. Rodgers ◽  
Stuart R. Dennis
Keyword(s):  
Reaction Norm ◽  
Age At Maturity ◽  
Predator Risk

scholarly journals Epidemic growth rates and host movement patterns shape management performance for pathogen spillover at the wildlife–livestock interface

2019 ◽  
Vol 374 (1782) ◽  
pp. 20180343 ◽  
Author(s):  
Kezia R. Manlove ◽  
Laura M. Sampson ◽  
Benny Borremans ◽  
E. Frances Cassirer ◽  
Ryan S. Miller ◽  
...  
Keyword(s):  
Growth Rates ◽  
Life Histories ◽  
Animal Health ◽  
Movement Patterns ◽  
Health Food ◽  
Management Options ◽  
Management Performance ◽  
Fast Growing ◽  
Management Actions ◽  
Host Movement

Managing pathogen spillover at the wildlife–livestock interface is a key step towards improving global animal health, food security and wildlife conservation. However, predicting the effectiveness of management actions across host–pathogen systems with different life histories is an on-going challenge since data on intervention effectiveness are expensive to collect and results are system-specific. We developed a simulation model to explore how the efficacies of different management strategies vary according to host movement patterns and epidemic growth rates. The model suggested that fast-growing, fast-moving epidemics like avian influenza were best-managed with actions like biosecurity or containment, which limited and localized overall spillover risk. For fast-growing, slower-moving diseases like foot-and-mouth disease, depopulation or prophylactic vaccination were competitive management options. Many actions performed competitively when epidemics grew slowly and host movements were limited, and how management efficacy related to epidemic growth rate or host movement propensity depended on what objective was used to evaluate management performance. This framework offers one means of classifying and prioritizing responses to novel pathogen spillover threats, and evaluating current management actions for pathogens emerging at the wildlife–livestock interface. This article is part of the theme issue ‘Dynamic and integrative approaches to understanding pathogen spillover’.

The Collapse and Recovery of a Small Whitefish Fishery

1956 ◽  
Vol 13 (1) ◽  
pp. 135-146 ◽  
Author(s):  
Richard B. Miller
Keyword(s):  
Growth Rates ◽  
Eutrophic Lake ◽  
Age At Maturity ◽  
Considerable Effort ◽  
Commercial Catch ◽  
Shallow Eutrophic Lake ◽  
Strong Winds ◽  
Egg Destruction ◽  
Catch Statistics

Pigeon Lake, Alberta, is a shallow eutrophic lake with a sandy basin, gentle contours and an area of 40 square miles. It contains whitefish, pike, yellow walleye, perch, burbot, white suckers and spottail shiners. The whitefish have been commercially exploited for many years and catch statistics are available from 1918.In 1941 a greatly increased catch of whitefish was permitted. Large annual yields continued until 1946; in 1947, in spite of considerable effort, a very small catch was made. Since this collapse fishing was prohibited in two years and light in two years. The lake now contains a normal whitefish population.Samples of the commercial catch during this period showed that the average age of the fish fell from 5.1 to 2.3 years, then, after collapse, increased to 5.7 years. Growth rates increased greatly, then decreased to the original level. Age at maturity decreased from five to two years.Calculations of the number of fish each year-class contributed to the fishery reveal that the collapse of the fishery was not due to overfishing; the weak year-classes which caused the collapse had parent year-classes of normal abundance. It is suggested that egg destruction by strong winds may have caused the weak year-classes.

scholarly journals A framework for ecosystem impacts assessment using an indicator approach

2005 ◽  
Vol 62 (3) ◽  
pp. 592-597 ◽  
Author(s):  
P.A. Livingston ◽  
K. Aydin ◽  
J. Boldt ◽  
J. Ianelli ◽  
J. Jurado-Molina
Keyword(s):  
Fishery Management ◽  
Ecosystem Impacts ◽  
Implementation Challenges ◽  
Management Actions ◽  
Indicator Approach ◽  
Research Organizations ◽  
Ecosystem Indicators ◽  
Ecosystem Level ◽  
Associated Species ◽  
The Impact

Abstract Assessment of the historical, present, and future states of marine ecosystems and the effects that humans and climate have on the state of an ecosystem are crucial to the scientific advice required to implement an ecosystem-based fishery management system. Management of federal groundfish fisheries in Alaska considers not just the target fishery, but also the possible impact those fisheries might have on other species and the ecosystem. Management actions have ranged from providing protection of endangered species in the region to preventing new fisheries from starting on key foodweb components such as forage fish. A scientific framework for providing ecosystem-based advice that puts the ecosystem first has been evolving over the past few years. This framework provides a way of assessing ecosystem factors that influence target species, the impact the target fishery may have on associated species, and ecosystem-level impacts of fishing. An indicator approach that describes ecosystem status, and trends and measures of human and climate influence has been developed to provide advice to fishery managers. This approach is now being expanded to utilize a variety of models to predict possible future trends in various ecosystem indicators. Future implementation challenges include the refinement of these predictive models, and the inclusion of climate into the models. Identification of sensitive and meaningful ecosystem indicators is also required before a more formalized decision-making process, one that includes ecosystem considerations, can be developed. Most important, the culture of fishery management and research organizations needs to change to embrace the ecosystem-based protections already mandated by various laws.

Useful Trends for Predicting Corrosion Growth

2012 ◽  
Author(s):  
Shahani Kariyawasam ◽  
Hong Wang
Keyword(s):  
Growth Rates ◽  
Critical Size ◽  
Rate Variation ◽  
Growth Data ◽  
Limit States ◽  
Critical Limit ◽  
Inspection Interval ◽  
Integrity Management ◽  
External Corrosion ◽  
Insight Into

The objective of an effective corrosion management program is to identify and mitigate corrosion anomalies before they reach critical limit states. Often as there are many anomalies on pipelines an optimized program will mitigate the few corrosion anomalies that may grow to a critical size within the next inspection interval, without excavating many of the anomalies that will not grow to a critical size. This optimization of the inspection interval and the selection of anomalies to mitigate depend on understanding of corrosion growth. Prediction of corrosion growth is challenging because growth with time is non linear and highly location specific. These characteristics make simplistic approaches such as using maximum growth rates for all defects impractical. Therefore it is important to understand the salient aspects of corrosion growth so that appropriate decisions on excavation and re-inspection can be made without compromising safety or undertaking undue amounts of mitigative activities. In the pipeline industry corrosion growth between two in line inspections (ILIs) has been measured by comparing one ILI run to the next. However many types of ILI comparison methodologies have been used in the past. Within the last decade or two comparison techniques have evolved from box matching of defect samples to signal matching of the total defect populations. Multiple comparison analyses have been performed on the TransCanada system to establish corrosion growth rates. Comparison of the results from these various analyses gives insight into the accuracy and uncertainty of each type of estimate. In an effective integrity management process the best available corrosion growth data should be used. To do so it is important to understand the conservatism and the uncertainty involved in each type of estimate. When using a run-comparison to predict future growth it is assumed that the growth within the last ILI interval will continue (with associated uncertainty) during the next inspection interval. The validity of these assumptions is examined in this study. In the context of this paper these assumptions are validated for external corrosion on onshore pipelines. Characteristics of internal and offshore corrosion are very different in space and time variation. Correlations of external corrosion growth in onshore pipelines with defect size and location are also examined. Learning from multiple corrosion growth studies gives insight into the actual corrosion rate variation along a pipeline as well as general growth characteristics. Different types of corrosion growth modeling for use in probabilistic or deterministic integrity management programs are also discussed.

scholarly journals Growth Rate Variation and Larval Survival: Inferences from an Individual-Based Size-Dependent Predation Model

1993 ◽  
Vol 50 (1) ◽  
pp. 133-142 ◽  
Author(s):  
James A. Rice ◽  
Thomas J. Miller ◽  
Kenneth A. Rose ◽  
Larry B. Crowder ◽  
Elizabeth A. Marschall ◽  
...  
Keyword(s):  
Growth Rate ◽  
Growth Rates ◽  
Individual Variability ◽  
Individual Growth ◽  
Rate Variation ◽  
High Survival ◽  
Initial Growth ◽  
Size Dependent ◽  
The Mean ◽  
Selection For

We used an individual-based Monte Carlo simulation model to explore how changes in the mean and variance of growth rates of individuals in a larval fish cohort interact with size-dependent predation to affect the number and characteristics of individual survivors. Small changes in initial cohort mean growth rate can change survival over the first 60 d of life 10-to 30-fold. But when variance in growth rate among individuals is high, survival can be substantially higher than expected from the initial mean cohort growth rate. Selection for faster-growing individuals becomes stronger with increasing variance and increasing predation rate. In some cases, > 80% of the survivors may come from the upper 25% of the initial growth rate distribution, and the mean growth rate of the survivors may exceed twice the initial mean growth rate. When individual growth rates change from day to day rather than remaining constant, the contribution of atypical individuals is accentuated even further. Counterintuitively, most of the selection for faster-growing individuals happens only after the majority of mortality has already taken place. These results suggest that interactions between individual variability and selective mortality may have important cohort-level implications for survival in fishes.

scholarly journals Predicting the effects of area closures and fishing effort restrictions on the production, biomass, and species richness of benthic invertebrate communities

2006 ◽  
Vol 63 (5) ◽  
pp. 822-830 ◽  
Author(s):  
J.G. Hiddink ◽  
T. Hutton ◽  
S. Jennings ◽  
M.J. Kaiser
Keyword(s):  
Species Richness ◽  
North Sea ◽  
Fishery Management ◽  
Benthic Communities ◽  
Fishing Effort ◽  
Management Actions ◽  
The North ◽  
The North Sea ◽  
Effort Reduction ◽  
Positive Effect

AbstractTo effectively implement an Ecosystem Approach to Fisheries (EAF), managers need to consider the effects of management actions on the fishery and the ecosystem. Methods for assessing the effects on target stocks are generally well developed, but methods for assessing the effects on other components and attributes of the ecosystem are not. Area closures and effort controls are widely used fishery management tools that affect the distribution of fishing effort and may therefore have consequences for a range of species and habitats. An approach is developed to predict the effects of area closures and effort control on the biomass, production, and species richness of benthic communities in the North Sea. The redistribution of beam trawling effort as a result of management action was modelled with a random utility model, assuming that fishers selected fishing grounds on the basis of their knowledge of past catch rates. The effects of trawling on benthic invertebrates were predicted using a size-based model that accounted for differences in habitat among fishing grounds. Our simulations demonstrated that closures of different sizes and in different locations could have positive or negative effects on benthic communities. These predicted effects resulted from the trade-off between recovery in the closed areas and additional trawling effects in the open areas that arose from displaced fishing activity. In the absence of effort controls, closure of lightly fished areas had the strongest positive effect on benthic communities. Effort reduction also had a positive effect. Therefore, area closures in lightly fished areas, coupled with effort reduction, are expected to minimize the effects of fishing on benthic communities. As it was not possible to access full international data for the North Sea beam trawl fleet, the results of the analyses are illustrative rather than complete. Nevertheless, what is demonstrated is an effective approach for assessing the environmental consequences of fishery management action that can be used to inform management decision-making as part of an EAF.

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