scholarly journals Effects of Forest Fire on Young-of-the-year Northern Pike, Esox lucius, in the Northwest Territories

2010 ◽  
Vol 124 (2) ◽  
pp. 104 ◽  
Author(s):  
Peter A. Cott ◽  
Barry A. Zajdlik ◽  
Kelly J. Bourassa ◽  
Marc Lange ◽  
Andrew M. Gordon
Keyword(s):  
Northwest Territories ◽  
Forest Fire ◽  
Relative Abundance ◽  
Forest Fires ◽  
Riparian Vegetation ◽  
Northern Pike ◽  
Esox Lucius ◽  
Physical Habitat ◽  
Abondance Relative ◽  
Young Of The Year

In 1998, a forest fire burned 58% of the forested shoreline surrounding Tibbitt Lake, Northwest Territories, including riparian vegetation used by Northern Pike (Esox lucius) as spawning habitat. This presented an opportunity to investigate the effects that habitat disturbance from a natural forest fire had on young-of-the-year (Y-O-Y) Northern Pike. Pike fry were collected from three burned and three unburned sites around Tibbitt Lake in 1999 (the first post-fire spawning season) and again in 2001. Differences in size and relative abundance were evaluated between sites. Y-O-Y Northern Pike were significantly larger at the unburned sites (P<0.01) and the relative abundance of Y-O-Y Northern Pike increased significantly at burned sites (alpha=0.1; P<0.07) following re-vegetation two years post fire. These differences may be due to fire-induced changes in physical habitat or food availability. Forest fires decrease the density of riparian vegetation, which likely provides better spawning and rearing habitat for Northern Pike in the long-term.En 1998, un feu de forêt a brûlé 58% de la rive boisée entourant le lac Tibbitt, situé dans les Territoires du Nord-Ouest, y compris la végétation riveraine utilisé par le grand brochet (Esox lucius) comme habitat de fraie. Cet événement a présenté une occasion pour étudier les effets causés par un feu de foret sur l'habitat de jeunes de l'année du grand brochet. Les jeunes brochets ont été recueillis sur trois sites brûlées et trois sites non brûlés autour du lac Tibbitt en 1999 (la première année de fraie après le feu de forêt) et à nouveau en 2001. La différence de grandeur et l'abondance relative des poissons ont été analysés entre les différents sites. Les jeunes grands brochets aux sites non-atteints par le feu étaient considérablement plus grands (P < 0,01) que ceux aux sites brulés. Les sites brulés, subissant une rapide revégétation dans les deux années après le feu, ont augmenté en abondance relative de jeunes grands brochets (alpha = 0,1, P < 0,07). Ces différences peuvent être dues aux changements induits par le feu sur l'aspect physique de l'habitat ou sur la disponibilité de nourriture. Les incendies de forêt réduisent la densité de la végétation riveraine, qui fournit probablement de meilleure habitat de fraie et d'alevinage pour le grand brochet à long terme.

Some Behavioral Interactions of Spottail Shiners (Notropis hudsonius), Yellow Perch (Perca flavescens), and Northern Pike (Esox lucius)

1973 ◽  
Vol 30 (8) ◽  
pp. 1161-1178 ◽  
Author(s):  
J. R. Nursall
Keyword(s):  
Yellow Perch ◽  
Perca Flavescens ◽  
Northern Pike ◽  
Esox Lucius ◽  
Behavioral Interactions ◽  
Change Of Direction ◽  
Pike Esox Lucius ◽  
Glide Path ◽  
Beaver Lake ◽  
Young Of The Year

Dense schools of spottail shiners (Notropis hudsonius) are common in shallow water in Beaver Lake, generally 0.25–0.30 m below the surface, with smaller individuals more numerous towards the top. Position in the shcool is maintained by short radius behavior. The course of an individual is maintained by a beat of the tail, a glide, a hesitation, and a change of direction. Each glide path represents the chord of an arc of short radius about some neighbor. Shiners respond to disturbance by flash expansion of loose cruising association. Schooling is obligatory. The black caudal spot is probaly multifunctional as a recognition mark and releaser.Yellow perch (Perca flavescens) show an ontogeny of behavior through young-of-the-year, aggregation-sized perch (aggp), subadults, and adults. They behave as individuals or associate as streams. Disturbance will cause a group of aggp to disperse or to stream. The adult manifestation of streaming is pack-hunting. The activity of one perch attracts the attention of others; this leads to streaming or pack-hunting. Pack-hunting improves the chance of some members of the pack, not necessarily the initiator, capturing active prey, by countering the allaesthetic protean escape reactions of organisms such as the spottail shiner. Large mixed aggregations of spottail shiners and aggp are fortuitous.Northern pike (Esox lucius) are lone, opportunistic predators whose hunting technique combines in sequence motionlessness, axial tracking, and lunging. Prey may be swallowed head- or tailfirst, or sideways.The species studied here show a range of gregariousness, from the solitary pike, through the facultative nonpolarized and polarized schools of perch, to obligate nonpolarized and polarized schools of shiners.

Feeding Flexibility in Northern Pike (Esox lucius): Fish versus Invertebrate Prey

1989 ◽  
Vol 46 (4) ◽  
pp. 666-669 ◽  
Author(s):  
Lauren J. Chapman ◽  
William C. Mackay ◽  
Craig W. Wilkinson
Keyword(s):  
Northwest Territories ◽  
Standard Length ◽  
Stomach Contents ◽  
Northern Pike ◽  
Esox Lucius ◽  
Frequency Of Occurrence ◽  
Pike Esox Lucius ◽  
Invertebrate Prey ◽  
Seasonal Basis

We describe the frequency of occurrence of fish and invertebrates in the stomach contents of northern pike (Esox lucius) from eight populations in Alberta and the Northwest Territories. Lakes were sampled one to eight times between 1979 and 1985, and a total of 899 pike were examined (mean standard length = 44 ± 8 cm, SD). Although northern pike are widely considered to be top aquatic piscivores, we found that the frequency of occurrence of invertebrates was high, at least on a seasonal basis, in some systems. In all of the lakes considered, the frequency of occurrence of fish (expressed as a percentage of non-empty stomachs) was 88% or greater in one or more of the sample periods. However, diets where the frequency of occurrence of invertebrates was greater than 90% occurred in three of the populations in one or more of the sample periods. The frequency of occurrence of invertebrates was negatively correlated with the percentage of empty stomachs, while the frequency of occurrence of fish was positively related to the percentage of empty stomachs. Invertebrate feeding was not limited exclusively to smaller pike; invertebrates were found in the stomachs of pike 24 to 60 cm long (standard length).

Assimilation Efficiency of Dietary Methylmercury by Northern Pike (Esox lucius)

1979 ◽  
Vol 36 (12) ◽  
pp. 1516-1519 ◽  
Author(s):  
G. R. Phillips ◽  
R. W. Gregory
Keyword(s):  
Key Words ◽  
Cyprinus Carpio ◽  
Assimilation Efficiency ◽  
Northern Pike ◽  
Esox Lucius ◽  
Forage Fish ◽  
Pike Esox Lucius ◽  
Mercury Compounds ◽  
Carp Cyprinus Carpio ◽  
Young Of The Year

Northern pike (Esox lucius) retained an average of 19% (range 6–31%) of the methylmercury which they ingested during consumption of young-of-the-year carp (Cyprinus carpio) collected from a pond; carp accumulated methylmercury naturally while in the pond. The total amount of mercury in pike increased with time (up to 42 d) but concentration in the tissue decreased due to growth dilution; duration of ingestion did not influence efficiency of methylmercury assimilation. This value (19%) is considerably lower than most efficiencies reported in the literature, demonstrating that methylmercury in this forage fish is less readily available to a predator fish than previous studies implied. Key words: bioaccumulation, mercury compounds, predators, Esocidae

Response of a Boreal Northern Pike (Esox lucius) Population to Lake Impoundment: Wupaw Bay, Southern Indian Lake, Manitoba

1984 ◽  
Vol 41 (4) ◽  
pp. 706-714 ◽  
Author(s):  
R. A. Bodaly ◽  
L. F. W. Lesack
Keyword(s):  
Reproductive Success ◽  
Natural Variation ◽  
Northern Pike ◽  
Esox Lucius ◽  
Forage Fish ◽  
Terrestrial Vegetation ◽  
Transient Effect ◽  
Pike Esox Lucius ◽  
Discernible Effect ◽  
Young Of The Year

A population of northern pike (Esox lucius) in Wupaw Bay, Southern Indian Lake, Manitoba, was monitored for 1 yr prior to impoundment of the lake and for 5 yr after impoundment. Impoundment had a pronounced but transient effect on pike reproductive success. The abundance of young-of-the-year pike in 1977, the 1st yr following impoundment, was 4–10 times higher than in the following 3 yr. Flooded terrestrial vegetation was apparently conducive to pike reproductive success only in the 1st yr after inundation. A strong 1977 year-class was evident in gillnet catches 4 yr later. This year-class was slower growing and in poorer condition than other year-classes. The impoundment of Wupaw Bay had no discernible effect on the growth, condition, or mortality of the adult pike population, with the exception of changes ascribed to the presence of the large 1977 year-class. The growth of the adult pike population appeared to be limited by forage fish abundance, but variations in feeding on fish were largely unexplained and were probably due to natural variation. The year-to-year pattern of forage fish reproductive success could not be related to the timing of lake impoundment, but may have been related to summer water temperatures. Variations in feeding on invertebrates appeared to be due to postimpoundment increases in productivity, but these changes were insufficient to affect population parameters. Wupaw Bay surface area increased by only 9% as a result of lake impoundment, the smallest areal increase in the Southern Indian Lake reservoir. The influx of nutrients and flooded terrestrial vegetation was therefore much smaller than in other temperate reservoirs where increases in pike production have been observed.

scholarly journals A Collaborative Region Detection and Grading Framework for Forest Fire Smoke Using Weakly Supervised Fine Segmentation and Lightweight Faster-RCNN

Forests ◽  
2021 ◽  
Vol 12 (6) ◽  
pp. 768
Author(s):  
Jin Pan ◽  
Xiaoming Ou ◽  
Liang Xu
Keyword(s):  
Forest Fire ◽  
Forest Fires ◽  
Learning Strategy ◽  
Early Stage ◽  
Fire Detection ◽  
Surveillance Systems ◽  
Region Detection ◽  
Decision Network ◽  
Fire Smoke ◽  
Weakly Supervised

Forest fires are serious disasters that affect countries all over the world. With the progress of image processing, numerous image-based surveillance systems for fires have been installed in forests. The rapid and accurate detection and grading of fire smoke can provide useful information, which helps humans to quickly control and reduce forest losses. Currently, convolutional neural networks (CNN) have yielded excellent performance in image recognition. Previous studies mostly paid attention to CNN-based image classification for fire detection. However, the research of CNN-based region detection and grading of fire is extremely scarce due to a challenging task which locates and segments fire regions using image-level annotations instead of inaccessible pixel-level labels. This paper presents a novel collaborative region detection and grading framework for fire smoke using a weakly supervised fine segmentation and a lightweight Faster R-CNN. The multi-task framework can simultaneously implement the early-stage alarm, region detection, classification, and grading of fire smoke. To provide an accurate segmentation on image-level, we propose the weakly supervised fine segmentation method, which consists of a segmentation network and a decision network. We aggregate image-level information, instead of expensive pixel-level labels, from all training images into the segmentation network, which simultaneously locates and segments fire smoke regions. To train the segmentation network using only image-level annotations, we propose a two-stage weakly supervised learning strategy, in which a novel weakly supervised loss is proposed to roughly detect the region of fire smoke, and a new region-refining segmentation algorithm is further used to accurately identify this region. The decision network incorporating a residual spatial attention module is utilized to predict the category of forest fire smoke. To reduce the complexity of the Faster R-CNN, we first introduced a knowledge distillation technique to compress the structure of this model. To grade forest fire smoke, we used a 3-input/1-output fuzzy system to evaluate the severity level. We evaluated the proposed approach using a developed fire smoke dataset, which included five different scenes varying by the fire smoke level. The proposed method exhibited competitive performance compared to state-of-the-art methods.

scholarly journals Short-Term Effects of Fire Severity on Vegetation Based on Sentinel-2 Satellite Data

2021 ◽  
Vol 13 (1) ◽  
pp. 432
Author(s):  
Aru Han ◽  
Song Qing ◽  
Yongbin Bao ◽  
Li Na ◽  
Yuhai Bao ◽  
...  
Keyword(s):  
Forest Fire ◽  
Forest Fires ◽  
Vegetation Change ◽  
Fire Severity ◽  
Dynamic Change ◽  
Burned Area ◽  
Fire Event ◽  
Vegetation Dynamic ◽  
Area Index ◽  
Sentinel 2

An important component in improving the quality of forests is to study the interference intensity of forest fires, in order to describe the intensity of the forest fire and the vegetation recovery, and to improve the monitoring ability of the dynamic change of the forest. Using a forest fire event in Bilahe, Inner Monglia in 2017 as a case study, this study extracted the burned area based on the BAIS2 index of Sentinel-2 data for 2016–2018. The leaf area index (LAI) and fractional vegetation cover (FVC), which are more suitable for monitoring vegetation dynamic changes of a burned area, were calculated by comparing the biophysical and spectral indices. The results showed that patterns of change of LAI and FVC of various land cover types were similar post-fire. The LAI and FVC of forest and grassland were high during the pre-fire and post-fire years. During the fire year, from the fire month (May) through the next 4 months (September), the order of areas of different fire severity in terms of values of LAI and FVC was: low > moderate > high severity. During the post fire year, LAI and FVC increased rapidly in areas of different fire severity, and the ranking of areas of different fire severity in terms of values LAI and FVC was consistent with the trend observed during the pre-fire year. The results of this study can improve the understanding of the mechanisms involved in post-fire vegetation change. By using quantitative inversion, the health trajectory of the ecosystem can be rapidly determined, and therefore this method can play an irreplaceable role in the realization of sustainable development in the study area. Therefore, it is of great scientific significance to quantitatively retrieve vegetation variables by remote sensing.

Catchments affect growth rate of Northern Pike, Esox lucius, in subarctic lakes

2021 ◽  
Vol 83 (3) ◽  
Author(s):  
Mehdi Moslemi-Aqdam ◽  
George Low ◽  
Mike Low ◽  
Brian A. Branfireun ◽  
Heidi K. Swanson
Keyword(s):  
Growth Rate ◽  
Northern Pike ◽  
Esox Lucius ◽  
Subarctic Lakes ◽  
Pike Esox Lucius

scholarly journals Empirical Research on Climate Warming Risks for Forest Fires: A Case Study of Grade I Forest Fire Danger Zone, Sichuan Province, China

2021 ◽  
Vol 13 (14) ◽  
pp. 7773
Author(s):  
San Wang ◽  
Hongli Li ◽  
Shukui Niu
Keyword(s):  
Wind Speed ◽  
Forest Fire ◽  
Climate Warming ◽  
Forest Fires ◽  
Meteorological Factors ◽  
Sichuan Province ◽  
Danger Zone ◽  
Climatic Regions ◽  
Area Burned ◽  
Forest Fire Danger

The Sichuan province is a key area for forest and grassland fire prevention in China. Forest resources contribute significantly not only to the biological gene pool in the mid latitudes but also in reducing the concentration of greenhouse gases and slowing down global warming. To study and forecast forest fire change trends in a grade I forest fire danger zone in the Sichuan province under climate change, the dynamic impacts of meteorological factors on forest fires in different climatic regions were explored and a model between them was established by using an integral regression in this study. The results showed that the dominant factor behind the area burned was wind speed in three climatic regions, particularly in Ganzi and A’ba with plateau climates. In Ganzi and A’ba, precipitation was mainly responsible for controlling the number of forest fires while it was mainly affected by temperature in Panzhihua and Liangshan with semi-humid subtropical mountain climates. Moreover, the synergistic effect of temperature, precipitation and wind speed was responsible in basin mid-subtropical humid climates with Chengdu as the center and the influence of temperature was slightly higher. The differential forest fire response to meteorological factors was observed in different climatic regions but there was some regularity. The influence of monthly precipitation in the autumn on the area burned in each climatic region was more significant than in other seasons, which verified the hypothesis of a precipitation lag effect. Climate warming and the combined impact of warming effects may lead to more frequent and severe fires.

Associations Between Ambient Particulate Air Pollution and Cognitive Function in Indonesian Children Living in Forest Fire–Prone Provinces

2021 ◽  
pp. 101053952110317
Author(s):  
Bin Jalaludin ◽  
Frances L. Garden ◽  
Agata Chrzanowska ◽  
Budi Haryanto ◽  
Christine T. Cowie ◽  
...  
Keyword(s):  
Air Pollution ◽  
Cognitive Function ◽  
Forest Fire ◽  
Forest Fires ◽  
Regression Models ◽  
Individual Factors ◽  
Aerodynamic Diameter ◽  
Particulate Air Pollution ◽  
Multivariable Models ◽  
Particulate Matter 2.5

Smoke from forest fires can reach hazardous levels for extended periods of time. We aimed to determine if there is an association between particulate matter ≤2.5 µm in aerodynamic diameter (PM2.5) and living in a forest fire–prone province and cognitive function. We used data from the Indonesian Family and Life Survey. Cognitive function was assessed by the Ravens Colored Progressive Matrices (RCPM). We used regression models to estimate associations between PM2.5 and living in a forest fire–prone province and cognitive function. In multivariable models, we found very small positive relationships between PM2.5 levels and RCPM scores (PM2.5 level at year of survey: β = 0.1%; 95% confidence interval [CI] = 0.01% to 0.19%). There were no differences in RCPM scores for children living in forest fire–prone provinces compared with children living in non-forest fire–prone provinces (mean difference = −1.16%, 95% CI = −2.53% to 0.21%). RCPM scores were lower for children who had lived in a forest fire–prone province all their lives compared with children who lived in a non-forest fire–prone province all their life (β = −1.50%; 95% CI = −2.94% to −0.07%). Living in a forest fire–prone province for a prolonged period of time negatively affected cognitive scores after adjusting for individual factors.

Sign in / Sign up

Export Citation Format

Share Document