Browsing All Posts filed under »fish«

Getting the message across

October 8, 2018

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Since recreational boaters can unintentionally spread invasive aquatic species while transporting boats and equipment from one body of water to another, it’s important that management agencies communicate the need for boaters to clean, drain and dry their gear after use.  Researchers used a questionnaire-based approach to find out if the way the “clean, drain and […]

How the food web affects river restoration

October 8, 2018

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River restoration commonly  concentrates on improving habitat quality for threatened fish populations.  However, because stream fish are strongly influenced by food availability, competition and predation, a case can be made for also incorporating food web modelling into the restoration process.  A group of environmental scientists developed an ecosystem model and applied it to a river-floodplain […]

Facing up to fish recognition

October 8, 2018

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Although it’s been shown that fish can visually discriminate between other members of their species, the traits used for recognition aren’t well understood.  Working with masked julie  (Julidochromis transcriptus), a Tanganyikan cichlid with stripe patterns from head to tail,  Japanese scientists  investigated the relative importance of  face and body markings in individual recognition.  They kept […]

Small fish species are more at risk

October 8, 2018

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Large-bodied animal species tend to have relatively low fecundity, long generation times and slow growth rates, which makes for low population turnover and a heightened risk of extinction.  This trend seems to be true for vertebrates such as mammals and marine fish, but not, it seems, for freshwater fish.  Australian ecologists explored the relationship between […]

Lakes are good for river species

October 8, 2018

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While it’s known that terrestrial landscape features, such as soil type, topography and land use, influence the abundance and distribution of stream fish, only a few studies have considered the possible effects of lakes on stream fish populations.  Biologists carried out a three-year study on native brook trout (Salvelinus fontinalis) in 36 streams in the […]

Floodplain fisheries and overexploitation

October 8, 2018

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The floodplain fishery in the Pantanal region of South America, one of the biggest wetlands in the world,  illustrates the difficulties often faced in managing resources in complex, highly changeable environments.  In the late 1970s and early 1980s, traditional small-scale commercial fishers accounted for around three-quarters of the fish catch.  In the absence of scientific […]

Fish life histories: filling in the gaps

July 5, 2018

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Estimates of life history parameters such as age at maturity, maximum body size and rates of growth and mortality play a crucial role in understanding and managing animal populations, but in the case of many species they’re lacking or poorly measured.  Fortunately however, compilations of existing estimates now exist, and these databases open up opportunities […]