Search results for "Population management"
showing 3 items of 3 documents
An analysis based on trawl-survey data of the state of the ‘Italian’ stock of Mullus barbatus in the Sicilian Channel, including management advice
1993
Abstract Data on the relative abundance of age groups obtained by statistically designed routine trawl surveys in approximately half of the Sicilian Channel were processed with commonly available microcomputer fish population dynamics packages. The species considered was Mullus barbatus , a unit stock of which had been previously identified in the study area. Analytical and management outcomes were also assessed in relative terms. Conditions and limits on both the analyses and the outcomes are discussed with reference to the particular case study.
Estimating the effects of winter-fishing: mobile echosounding under ice
1999
Abstract An echosounder with a tape recorder in a propeller-driven waterproof box (an echosounder shuttle) was used under the ice to monitor the vertical distribution and density of fish in a winter seining area of a Finnish lake in April 1997. The surveyed fish were at 3.5–8 m depth, and fish density was significantly lower after seining than before. The seine catch was about 10 kg ha−1, and the echosounding results showed a decrease of 7 kg ha−1 in the hauling area. There were some difficulties due to the low temperature, and minor problems with steering and leakage of the shuttle. We conclude that it is possible to make mobile echosurveys under the ice and estimate densities of wintering…
Biometric characterisation and taxonomic considerations of european rabbit Oryctolagus cuniculus (Linnaeus 1758) in Sicily (Italy)
2014
In Sicilian Mediterranean ecosystems the European rabbit Oryctolagus cuniculus is a keystone species, very important for popular small game species and for ecological reasons. However, its spread across the island seems to have decreased and fragmented in recent times, but until now no accurate population management has been carried out due to the lack of ethological, ecological and taxonomic knowledge. A biometric analysis of European rabbit specimens from Sicily to widen current taxonomic knowledge was performed. In this paper, 7 body variables and 23 cranial variables of 166 and 120 individuals, respectively, were examined. Thereafter, the results were compared with biometric data from o…