Efficiency of a New Reverse-Bait Trigger Snap Trap for Invasive Rats and a New Standardised Abundance Index

2011 ◽  
Vol 48 (5) ◽  
pp. 308-318 ◽  
Author(s):  
Jörn Theuerkauf ◽  
Sophie Rouys ◽  
Hervé Jourdan ◽  
Roman Gula
2008 ◽  
Vol 6 (1) ◽  
Author(s):  
Maria Massora

<em>A study was done to search the composition and abundance of fish species in the waters of the Doreri Gulf the District of Manokwari, from September - October 2005.  The fish catchments wash about 143 specimens consist of 49 species included in 23 families.  The species of fish with a high abundance index consists of Nemipterus celebicus, Upeneus sundaicus, and Upeneus sulphureus.  Those fishes have a high economic value in the market of Manokwari</em>


2021 ◽  
Vol 11 (4) ◽  
pp. 1814-1828
Author(s):  
Carly R. Muletz‐Wolz ◽  
Erin Wilson Rankin ◽  
Sarah McGrath‐Blaser ◽  
Madhvi Venkatraman ◽  
Jesús E. Maldonado ◽  
...  
Keyword(s):  

2003 ◽  
Vol 65 (1-3) ◽  
pp. 453-465 ◽  
Author(s):  
Johan C. Groeneveld ◽  
Douglas S. Butterworth ◽  
Jean P. Glazer ◽  
George M. Branch ◽  
Andrew C. Cockcroft

2010 ◽  
Vol 70 (1) ◽  
pp. 37-45 ◽  
Author(s):  
JT. Mendonça ◽  
JR. Verani ◽  
N. Nordi

The Estuary of Cananéia, Iguape and Ilha Comprida is a part of the Estuarine Lagoon System of Cananéia, Iguape and Paranaguá , on the south coast of São Paulo State, Brazil. It has been recognised for its high standards of environmental conservation. The objective of this paper was to assess the blue crab (Callinectes sapidus) fishing in the region, from January 1998 to December 2006, and obtain supportive data to implement technical rules for the rational exploitation and resulting conservation of this resource. The results show a remarkable decrease in the fisheries' abundance index (CPUE) up to 2005, from 9.4 to 4.0 kg/hour, mainly caused by an increase in fishing effort, from 1,960 to 13,776 hours on a yearly basis. With the decrease in the fishing effort in 2005 and 2006, the abundance index reacted positively, indicating a recovery of the exploited population. Due to the lack of appropriate regulation limiting the fishing effort and organising the fluctuating admission rates of new fishermen, there is a noticeable increase of the effort, above the sustainable level. Therefore, there is a need for measures to limit and control the admission of fishermen in this activity. One of the measures to be considered is the establishment of regular periods where fishing the species is prohibited (called "defeso"), each year, especially from September to January. Another measure is to create a fishermen registry and special licenses, to limit the number of new entrants. Such actions require, for their implementation, a co-managed initiative, involving the blue crab fishermen themselves, governmental agencies and resource management researchers, and the integration of ecological, socioeconomic and cultural dimensions.


2015 ◽  
Author(s):  
Ethan Linck ◽  
Eli S Bridge ◽  
Jonah M Duckles ◽  
Adolfo G Navarro-Sigüenza ◽  
Sievert Rohwer

Natural history museum collections (NHCs) represent a rich and largely untapped source of data on demography and population movements. NHC specimen records can be corrected to a crude measure of collecting effort and reflect relative population densities with a method known as abundance indices. We plot abundance index values from georeferenced NHC data in a 12-month series for the new world migratory passerine Passerina ciris across its molting and wintering range in Mexico and Central America. We illustrate a statistically significant change in abundance index values across regions and months that suggests a quasi-circular movement around its non-breeding range, and use enhanced vegetation index (EVI) analysis of remote sensing plots to demonstrate non-random association of specimen record density with areas of high primary productivity. We demonstrate how abundance indices from NHC specimen records can be applied to infer previously unknown migratory behavior, and be integrated with remote sensing data to allow for a deeper understanding of demography and behavioral ecology across space and time.


Author(s):  
Ekaterina Leonidovna Voropaeva ◽  
Elizaveta L'vovna Liberman

In the Lower Irtysh basin there is rich diversity of the fish population, bream Abramis brama (Linnaeus, 1758) is one of the representatives. Having been introduced into the Ob’-Irtysh basin more than 100 years ago, it dispersed in most reservoirs due to its wide adaptive variability and high fecundity. In the process of fish introduction, the new types of parasites replenish the parasitic communities of water bodies. As a result of studying bream parasitic fauna after its distribution there has been stated a decrease in parasite species composition, in comparison with its maternal habitat. Studies conducted in 2017-2018 allowed to fund out infectiousness of bream with four types of monogeneans: Gyrodactylus elegans , Dactylogyrus falcatus , D. wunderi , D. zandti . There has been recorded 100% extensiveness of invasion by dactylogyruses. Extensiveness of invasion by G.elegans in 2017 amounted to 100%, in 2018 - 74.2%. The abundance index of G.elegans in 2018 decreased in comparison with 2017 and amounted to 55.9 and 83.4 specimens, respectively. Abundance index of Dactylogyrus spp. decreased in 2018 and amounted to 27.9 specimens, compared to 2017 when there were registered 55.9 specimens. In 2017, the examined bream individuals showed a total predominance of gyrodactyluses over dactylogyruses, whereas in 2018 the number of Dactylogyrus spp was higher than of G. elegans . The of infectiousness of bream was first established after its distribution in the Ob’-Irtysh basin, when it was infected by the specific monogenean - Dactylogyrus falcatus (Wedl, 1857).


2021 ◽  
Author(s):  
Emiliano Arona ◽  
Adrián Schiavini

Abstract Free roaming dogs (FRD) in cities represent an increasing problem. Authorities need numbers of FRDs to evaluate policies implemented and to monitor the dog population. We estimated the number of FRD in Ushuaia city, Argentina, using a photographic capture-recapture methodology. We estimated an abundance index, the power to detect changes in the index, and modeled factors that may explain the spatial distribution of FRD and their welfare status. During three surveys, covering 72 transects along streets (9.9% of the street layout of Ushuaia), we recorded 539 different FRDs. A model with individual heterogeneity in capture-recapture probability gave 12,797 FRDs (95% CI 10,979 − 15,323), reflecting a dog:human relation of 1:6, higher than the relation recommended by the WHO. The abundance index was similar between surveys (8.13 ± 1.36, 8.38 ± 1.46 and 9.55 ± 1.28 dogs/km). The difference needed to detect changes in the index is about twice the standard error of estimates. The best model explaining dogs’ abundance included only geographical location, although two neighbourhoods with 9 transects stand out with 181 different FRDs identified. Together with the good overall dogs’ welfare status, modeling suggests that the behavior of owners is the main driver for the presence of FRDs. We recommend the use of photographic capture-recapture methodologies instead of simple index estimation, due to the small additional effort required and the improved accuracy and precision obtained. We also recommend a permanent systematic design for future surveys, increase the number of survey occasions, and improve the survey process.


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