sustainable harvest
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2021 ◽  
Author(s):  
Paul Moran ◽  
Vanessa J Tuttle ◽  
Susan Bishop ◽  
Larrie LaVoy

Bycatch impacts on non-target species present significant management problems in diverse fisheries throughout the world. Despite successful efforts to minimize bycatch in US West Coast Pacific Hake fisheries, these impacts remain a concern, particularly for sensitive populations of Chinook Salmon. NOAA Fisheries needed predictive models to estimate proportions of Chinook Salmon Evolutionarily Significant Units (ESUs) expected in bycatch. We used genetic mixture analysis to estimate ESU proportions from at-sea bycatch between 2008 and 2015. Using latitude as a predictor and applying jackknife cross validation, we found Dirichlet regression more accurately estimated abundant ESUs, whereas multinomial logistic regression performed better with rare ESUs. This targeted, ESU-specific approach showed the spatial distribution of sensitive stocks in bycatch and supported NOAA's obligations to forecast impacts on listed ESUs. The overarching goal of this continuing work is to maximize sustainable harvest while protecting threatened and endangered Chinook Salmon ESUs.


Author(s):  
Montes-Perez Ruben ◽  
Lopez-Coba Ermilo ◽  
Pacheco-Sierra Gualberto ◽  
May-Cruz Christian ◽  
Sierra-Gomez Andrés III

Aims: Estimate the population density of deer in the municipality of Tzucacab, Yucatán in the periods of 2003-2004, 2007-2008 and 2008-2009, determine the use of the habitat by these populations and the sustainability of the deer harvest from the estimated population densities. Study Design: A descriptive and vertical free-living deer population study was carried out in southern Yucatan, Mexico over a three-year period. Methodology: The map of the municipality of Tuzcacab was zoned in quadrants of 36 km2, completing a total of 36 quadrants; Unrestricted random sampling was applied to select seven quadrants in the period from 2003 to 2004 and 18 in each annual period between 2007 and 2009. Population samplings were carried out by applying three population estimation methods: direct sighting in a linear transect of 5 km in length, count of tracks in transect except period 2003-2004 and faecal pellets group count in plots. The evaluation of the use of habitat was carried out using the Bonferroni intervals, from the data of faecal pellets count. The evaluation of the deer harvest was carried out using the sustainable harvest model. Results: The population densities were different in each method, the density by the excreta count was 4.63 ± 2.49 deer / km2 in 2003-2004, 0.294 ± 0.198 deer / km2 in 2007-2008, and in the year 2008-2009 was 0.419 ± 0.0000085 deer / km2. Habitat use in 2007-08 and 2008-2009 was higher in the tropical forest, lower in agriculture and similar to that expected in secondary succession forest (acahual). The values of sustainable harvest, taking as a value the density per count of excreta in the plot because it showed the highest statistical precision, in the period 2003-04 it is sustainable, but in the period from 2007 to 2009 it is not sustainable. Conclusion: The population densities of deer (O. virginianus and M. americana) in Tuzcacab by means of the excreta count method, have decreased significantly. The habitat use preference is the tropical forest. The deer harvest in the period from 2007 to 2009 is not sustainable.


2021 ◽  
Vol 129 ◽  
pp. 105355
Author(s):  
Cinthia Carolina Abbona ◽  
Gustavo Neme ◽  
Jeff Johnson ◽  
Adolfo Gil ◽  
Ricardo Villalba ◽  
...  

2021 ◽  
Author(s):  
Wade T Tinkham ◽  
Mike A Battaglia ◽  
Chad M Hoffman

Abstract Small-tree development affects future stand dynamics and dictates many ecological processes within a site. Accurately representing this critical component of stand development is important for evaluating treatment alternatives from fuel hazard reduction to harvest scheduling. As with all forest growth, competition with other vegetation is known to regulate small-tree growth dynamics. This study uses three Nelder plots with 45 years of ponderosa pine growth to understand competition effects on seedling growth and evaluate the Forest Vegetation Simulator (FVS) Central Rockies (CR) variant’s ability to represent these dynamics. Removal of herbaceous competition before planting increased tree diameters by 50–135% and height by 35–75% across a planting density gradient at age 12. However, by age 45, the effect of herbaceous competition on tree size was no longer evident. Instead, trees at the lowest planting density had diameters 2.5–3 times larger than the most densely grown trees. Forest Vegetation Simulator (FVS) simulations underpredicted diameter at breast height (dbh) by 35–50% and 0–35% for 12 and 45-year-old trees, respectively. There was an underprediction bias of 15–20% for heights at age 12 and overpredictions of 5–10% at age 45. Continuous underprediction of dbh will affect the reliability of modeled fuel treatment longevity and sustainable harvest scheduling. Study Implications: Management and modeling of small-tree growth can affect decision-making for a range of activities, from assessing fuel treatment effectiveness to sustainable harvest scheduling. Effective small-tree density management can increase tree diameters at age 45 by 2.5–3 times the diameter of unthinned sites. FVS-CR underpredicted age 12 heights by 0–45% and age 45 diameters by 0–35% as a function of planting density, suggesting that the model fails to capture the intensity or timing of density-induced competition. These underpredictions will inflate the length of time fuel treatments remain effective and decrease projected sustainable harvest levels supported by responsible management.


2021 ◽  
Vol 8 (01 _ Sp 1) ◽  
Author(s):  
Tapas Paramanik ◽  
◽  
Shantanu Bhattacharyya ◽  
Keyword(s):  

Author(s):  
Christian J. Rivera ◽  
Suzanne K. Macey ◽  
Mary E. Blair ◽  
Eleanor J. Sterling

2021 ◽  
Vol 109 (1) ◽  
pp. 37-43
Author(s):  
V. Аlmashova ◽  
◽  
S. Onishenko ◽  
О. Yevtushenko ◽  
◽  
...  

Influence of vegetable pea seed treatment with boron and molybdenum on plant growth and development depending on sowing period The article is devoted to the influence of terms of sowing and processing of pea seeds with boron and molybdenum fertilizers on plant development in the conditions of the south of Ukraine. The possibility of obtaining a sustainable harvest and high quality pea products for its further preservation has been proved. It is established that the action of boron and molybdenum delays the onset of phenological phases of culture development, and the use of two different sowing dates allows to delay the onset of the phase of technological maturity for 6 days. This is important when harvesting for minimal crop losses of vegetable peas in southern Ukraine. Keywords: vegetable peas, nutrients, boron and molybdenum fertilizers, physiological processes, leaf surface index.


2020 ◽  
pp. 1-3
Author(s):  
Tambe R. S.
Keyword(s):  

Is the culture of earthworms. The purpose is to continually increase the number of worms in order to obtain a sustainable harvest. The worms are either used to expand a Vermicomposting operation or sold to customers who use them for the same or other purposes.


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