Population structure, movement and habitat preferences of the purple-spotted gudgeon, Mogurnda adspersa

2002 ◽  
Vol 53 (5) ◽  
pp. 909 ◽  
Author(s):  
George D. Boxall ◽  
John J. Sandberg ◽  
Frederieke J. Kroon
Keyword(s):  
Population Structure ◽  
Habitat Preference ◽  
Habitat Preferences ◽  
Pool Size ◽  
Habitat Characteristics ◽  
Effective Management ◽  
Prominent Feature ◽  
Management Options ◽  
Point Sampling ◽  
Far North

We examined the movement patterns and habitat preferences of Mogurnda adspersa in Pattersons Creek, a small, low-order, rainforest creek in Gillies Range State Forest, Far North Queensland, Australia. First, we conducted a capture and recapture study to document population structure and individual movements. Our results show that movement is a prominent feature of population behaviour of M. adspersa, with male gudgeons moving significantly more between pools than females, irrespective of gudgeon size. Second, we quantitatively described habitat characteristics of rainforest pools using point sampling. This data was then combined with capture data to describe the habitat preference of M. adspersa. Our results show that the number of gudgeons was positively related to pool size and decreased with increasing pool velocity. We discuss the results in light of effective management options for the species habitat in general, and Far North Queensland in particular.

Habitat preference of sea cucumbers:Holothuria atraandHolothuria edulisin the coastal waters of Sri Lanka

2011 ◽  
Vol 92 (3) ◽  
pp. 581-590 ◽  
Author(s):  
D.C.T. Dissanayake ◽  
G. Stefansson
Keyword(s):  
Sri Lanka ◽  
Habitat Preference ◽  
Sea Cucumber ◽  
Stock Assessment ◽  
Habitat Preferences ◽  
Organic Content ◽  
Habitat Characteristics ◽  
Seagrass Habitat ◽  
Underwater Visual Census ◽  
North West

Despite their economic importance, the ecology of many sea cucumber species is poorly understood and factors influencing their habitat preferences remain largely unexplained. The distribution and habitat preference of two sea cucumber species;Holothuria atraandHolothuria eduliswere studied off the north-west coast of Sri Lanka by underwater visual census in October 2008. The relationships between the density of each species and the habitat variables, such as mean grain size, organic content (% of dry weight), gravel (%), silt–mud (%), and depth, were examined using a generalized additive model. All these variables except silt–mud have significant influence (P < 0.05) on the habitat association ofH. atra. The shallow water (<10 m) seagrass habitat with sediments characterized by 2–3.5% organic content, 15–25% of gravel and coarse sand (0.7–1.2 mm) were the most preferred conditions byH. atra. High densities ofH. eduliswere found in the shallow (<10 m) depths of rocky areas with algae and seagrass. Favoured bottom sediment conditions ofH. eduliswere mainly similar to the conditions preferred byH. atra, except organic content which did not significantly influence the habitat preference of this species. The preference towards the specific habitat characteristics seems to be associated with their feeding and protection. An understanding of habitat preference would be useful to improve the management of these sea cucumber populations and enable more precise stock assessment.

Differentiation and Interrelations of Two Representatives of Laudakia stellio Complex (Reptilia: Agamidae) in Israel

2011 ◽  
Vol 4 (2) ◽  
pp. 102-114 ◽  
Author(s):  
Evgenyi N. Panov ◽  
Larissa Yu. Zykova
Keyword(s):  
Population Structure ◽  
Gene Flow ◽  
Habitat Preference ◽  
Additional Data ◽  
Near East ◽  
Field Studies ◽  
Subspecies Level ◽  
Limited Gene Flow ◽  
Study Sites ◽  
And Behavior

Field studies were conducted in Central Negev within the breeding range of Laudakia stellio brachydactyla and in NE Israel (Qyriat Shemona) in the range of an unnamed form (tentatively “Near-East Rock Agama”), during March – May 1996. Additional data have been collected in Jerusalem at a distance of ca. 110 km from the first and about 170 km from the second study sites. A total of 63 individuals were caught and examined. The animals were marked and their subsequent movements were followed. Social and signal behavior of both forms were described and compared. Lizards from Negev and Qyriat Shemona differ from each other sharply in external morphology, habitat preference, population structure, and behavior. The differences obviously exceed the subspecies level. At the same time, the lizards from Jerusalem tend to be intermediate morphologically between those from both above-named localities, which permits admitting the existence of a limited gene flow between lizard populations of Negev and northern Israel. The lizards from NE Israel apparently do not belong to the nominate subspecies of L. stellio and should be regarded as one more subspecies within the species.

scholarly journals Incoherent dimensionality in fisheries management: consequences of misaligned stock assessment and population boundaries

2020 ◽  
Author(s):  
Aaron M Berger ◽  
Jonathan J Deroba ◽  
Katelyn M Bosley ◽  
Daniel R Goethel ◽  
Brian J Langseth ◽  
...  
Keyword(s):  
Population Structure ◽  
Stock Assessment ◽  
Spatially Explicit ◽  
Spatial Simulation ◽  
Management Options ◽  
Spatially Explicit Models ◽  
Fisheries Policy ◽  
Simulation Estimation ◽  
Definition Of ◽  
Dynamic Population

Abstract Fisheries policy inherently relies on an explicit definition of management boundaries that delineate the spatial extent over which stocks are assessed and regulations are implemented. However, management boundaries tend to be static and determined by politically negotiated or historically identified population (or multi-species) units, which create a potential disconnect with underlying, dynamic population structure. The consequences of incoherent management and population or stock boundaries were explored through the application of a two-area spatial simulation–estimation framework. Results highlight the importance of aligning management assessment areas with underlying population structure and processes, especially when fishing mortality is disproportionate to vulnerable biomass among management areas, demographic parameters (growth and maturity) are not homogenous within management areas, and connectivity (via recruitment or movement) unknowingly exists among management areas. Bias and risk were greater for assessments that incorrectly span multiple population segments (PSs) compared to assessments that cover a subset of a PS, and these results were exacerbated when there was connectivity between PSs. Directed studies and due consideration of critical PSs, spatially explicit models, and dynamic management options that help align management and population boundaries would likely reduce estimation biases and management risk, as would closely coordinated management that functions across population boundaries.

scholarly journals NOTES ON THE ECOLOGY OF THE COLOMBIAN LEAFTOED GECKO (PHYLLODACTYLUS TRANSVERSALIS), ENDEMIC TO MALPELO ISLAND

2016 ◽  
Vol 42 (2) ◽  
Author(s):  
Mateo López Victoria ◽  
Matthias Jurczyk ◽  
Volkmar Wolters
Keyword(s):  
Population Size ◽  
Breeding Season ◽  
Habitat Preference ◽  
Habitat Preferences ◽  
Original Description ◽  
Tropical Pacific ◽  
Reference Points ◽  
Eastern Tropical Pacific ◽  
Reptile Species ◽  
Malpelo Island

The Colombian leaf-toed gecko (Phyllodactylus transversalis) is the least known reptile species of Malpelo Island (Eastern Tropical Pacific). In the 37 years since its original description, no single study strictly dedicated to this species has been conducted. With the goal of providing information on the ecology and population size of this gecko, data collected during two visits to the island are presented. Behavior and reproduction were studied by following individuals during the night and by searching for hidden individuals and eggs during the day. Population’s density and habitat preferences were estimated by classifying the island’s surfaces into four types and counting geckos inside those habitats within band transects. General morphological measurements of geckos were performed as reference points for future comparisons. Phyllodactylus transversalis lays its eggs in narrow crevices of rocks, apparently communally. Reproduction seems to take place during most of the year, probably associated with the peak breeding season of seabirds. Although conspecifics shared shelters during the day, densities during the night suggest no apparent habitat preference for foraging. Population size of this species was estimated at approximately 114000 individuals.

scholarly journals Coexisting ecosystem states in a tropical coastal lagoon under progressive eutrophication in the northern Cuban keys

2018 ◽  
Vol 82 (3) ◽  
pp. 139 ◽  
Author(s):  
Roberto González-De Zayas ◽  
Martin Merino-Ibarra ◽  
Patricia M. Valdespino-Castillo ◽  
Yunier Olivera ◽  
Sergio F. Castillo-Sandoval
Keyword(s):  
Residence Time ◽  
Coastal Lagoon ◽  
Spatial And Temporal Variability ◽  
Positive Trend ◽  
Water Residence Time ◽  
Effective Management ◽  
Management Options ◽  
Trophic Index ◽  
Tropical Coastal Lagoon ◽  
Mollusc Assemblages

Through a nested suite of methods here we contrast the coexistence of different ecosystem states in a tropical coastal lagoon, the Laguna Larga, with increasing eutrophication stress between 2007 and 2009. Water temperature averaged 27.4°C in the lagoon and showed a slight positive trend during the study period. Salinity averaged 35.0±6.2, exhibiting high spatial and temporal variability, and also a slight positive trend in time. In contrast, dissolved oxygen showed a substantial decreasing trend (–0.83 ml L–1 y–1; –13.3% y–1) over the period, while nutrients increased dramatically, particularly total phosphorus (2.6 µM y–1), in both cases sustaining the progression of eutrophication in the lagoon during the three years we sampled. The Karydis nutrient load-based trophic index showed that the lagoon has a spatial pattern of increasing eutrophication from the sea and the outer sector (oligotrophic-mesotrophic) to the central (mesotrophic) and the inner sector (mesotrophic-eutrophic). Two ecosystem states were found within the lagoon. In the outer oligotrophic sector, the dominant primary producers were macroalgae, seagrasses and benthic diatoms, while mollusc assemblages were highly diverse. In the inner and central sectors (where trophic status increased toward the inner lagoon) a phytoplankton-dominated ecosystem was found where mollusc assemblages are less diverse. In spite of the progression of eutrophication in the lagoon, these two different ecosystems coexisted and remained unchanged during the study period. Apparently, the effect of water residence time, which increases dramatically toward the inner lagoon, dominated over that of nutrient loadings, which is relatively more homogeneously distributed along the lagoon. Therefore, we consider that actions that reduce the water residence time are likely the most effective management options for this and other similarly choked lagoons.

scholarly journals Root-knot nematode (Meloidogyne incognita) and its management: a review

2020 ◽  
Vol 3 (2) ◽  
pp. 21-31
Author(s):  
Sudeep Subedi ◽  
Bihani Thapa ◽  
Jiban Shrestha
Keyword(s):  
Meloidogyne Incognita ◽  
Host Cells ◽  
Effective Management ◽  
Root Knot Nematode ◽  
Biotic And Abiotic Stresses ◽  
Management Options ◽  
Feeding Site ◽  
Second Stage ◽  
Stage Juvenile ◽  
Growth Quality

Root-knot nematode (RKN) Meloidogyne incognita stands out among the most harmful polyphagous endoparasite causing serious harm to plants, and distributed all over the globe. RKN causes reduced growth, quality and yield along with reduced resistance of the host against biotic and abiotic stresses. Infective second stage juvenile enters host roots with the help of the stylet and becomes sedentary getting into the vascular cylinder. Dramatic changes occur in host cells, making a specialized feeding site, induced by the secretion of effector protein by RKN. M. incognita can be controlled by nematicides, biocontrol agents, botanicals essential oils and growing resistant cultivars. Nematicides are no longer allowed to use in many parts of the world because of environmental hazards and toxicity to humans and other organisms. Researchers are concentrating on searching suitable alternatives to nematicides for effective management of M. incognita. This review mainly tries to explain the biology of M. incognita and different management options recommended in recent years. However, an effective and economical management of M. incognita remains an immense challenge.

Direct and residual contact toxicity of insecticides toHalyomorpha halys(Hemiptera: Pentatomidae)

2019 ◽  
Vol 151 (2) ◽  
pp. 209-218 ◽  
Author(s):  
A.E. Gradish ◽  
H. Fraser ◽  
C.D. Scott-Dupree
Keyword(s):  
United States Of America ◽  
Economic Loss ◽  
The United States ◽  
Invasive Pest ◽  
Contact Toxicity ◽  
Halyomorpha Halys ◽  
Effective Management ◽  
Management Options ◽  
Horticultural Crops ◽  
Contact Exposure

AbstractHalyomorpha halys(Stål) (Hemiptera: Pentatomidae) is a serious invasive pest of many agricultural and horticultural crops in Canada and the United States of America. To mitigate economic loss for growers, effective management options forH. halysare needed. We evaluated the efficacy of 12 insecticides (Beauveria bassiana(Balsamo-Crivelli) Vuillemin (Cordycipitaceae), boric acid, chlorpyrifos, clothianidin, flupryadifurone, λ-cyhalothrin, malathion, novaluron, sulfoxaflor, thiamethoxam, thiamethoxam + λ-cyhalothrin, and thiamethoxam + novaluron) currently used or with potential forH. halysmanagement by determining their direct and residual contact toxicity toH. halysnymphs. Each insecticide was tested at its Canadian label rate and half and twice that rate. With the exception of chlorpyrifos, nymph mortality was low (< 40%) following direct or residual contact exposure to all insecticides and rates. All surviving nymphs were severely affected (i.e., knocked down) by direct and residual contact exposure to neonicotinoids, while approximately 66% of nymphs were severely affected following exposure to sulfloxaflor residues at label and twice label rate. However, few nymphs were severely affected by all other insecticides and rates. Overall, our results suggest thatH. halysis not susceptible to many insecticides at current label rates for Canada. More research is needed to identify efficacious insecticides forH. halys.

scholarly journals Zanamivir: from drug design to the clinic

2001 ◽  
Vol 356 (1416) ◽  
pp. 1885-1893 ◽  
Author(s):  
Michael Elliott
Keyword(s):  
Clinical Trials ◽  
Antiviral Activity ◽  
Respiratory Tract ◽  
Early Treatment ◽  
Neuraminidase Inhibitors ◽  
Effective Management ◽  
Management Options ◽  
Influenza Illness ◽  
Clinically Significant ◽  
Complementary Strategy

The development of the neuraminidase inhibitors has revolutionized the management options for influenza. Zanamivir was the first such inhibitor to be approved for the treatment of influenza in humans. It is delivered by inhalation to the respiratory tract, which is the site of viral replication, in order to ensure immediate antiviral activity. Early treatment with zanamivir in clinical trials rapidly reduced the severity and duration of influenza symptoms and associated complications. Furthermore, chemoprophylaxis with zanamivir was shown to be effective in the prevention of influenza illness. To date, there is no evidence for the emergence of clinically significant zanamivir–resistant isolates. In conclusion, zanamivir offers a useful complementary strategy to vaccination in the effective management of influenza.

Sign in / Sign up

Export Citation Format

Share Document