A camera can accurately count freshwater fish, even in the thickest of underwater vegetation, a key finding for those who manage fisheries and control the invasive plant hydrilla, new University of Florida research shows.
The finding by UF/IFAS scientists can help researchers understand how many and which fish species are using dense plant habitats, said former UF/IFAS graduate student Kyle Wilson.
Former UF/IFAS doctoral student Andrew Barbour.
Former UF/IFAS graduate student Kyle Wilson prepares a equipment for his fish count
While cameras have been used to document fish behavior – including eating and breeding ─ this marks the first time scientists have used video to count fish in underwater plant habitats, Wilson said. In addition, no prior studies that used cameras to count fish verified their fish populations.
“It is commonly assumed that dense and invasive plants, like hydrilla, can drastically change fish habitat quality, primarily through changes in dissolved oxygen levels, water chemistry and habitat structure,” Wilson said. “Whether these changes are good or bad for fish has previously remained uncertain due to sampling problems in dense plant habitats. Using underwater cameras, we have shown that fish can and do use habitats we previously thought were too stressful for fish habitat.”
This is a big problem, especially with hydrilla, a plant that has invaded lakes throughout Florida, much of the U.S., Central America, South Africa and Australia, Wilson said. He estimated Florida spent up to $14 million per year throughout the 2000s to manage hydrilla, while the U.S. spent about $100 million per year in the 2000s for aquatic plant management.
In practical terms, researchers and conservation managers could use the UF/IFAS techniques to better understand how fish use other invasive aquatic plants as well, like Eurasian Watermilfoil, because it’s similar to hydrilla, Wilson said. Such approaches can be quite valuable in advising conservation plans and can help resolve stakeholder issues associated with these invasive plants.
“This ability to use video cameras to estimate fish abundance is a tremendous asset to fisheries management, allowing us to evaluate fish habitat use in areas where previously no sampling method was effective,” Wilson said. Australian researchers studying fish ecology have used cameras to count fish in the relatively clear waters at the Great Barrier Reef, but no research has peered through a lens to detect fish in thick vegetation like this study. “Previously, researchers that used cameras have had to make several broad assumptions that cameras work well in sampling fish. Now we know they work well.”
UF/IFAS researchers specifically focused their study on ponds with plenty of hydrilla, Wilson said, but have also conducted preliminary camera work on Lake Tohopekaliga in the Kissimmee Chain of Lakes Area.
To research his master’s thesis, Wilson lowered a camera into the water from a boat in three experimental ponds in Gainesville. He discovered the video counted freshwater fish, such as largemouth bass and bluegill sunfish – even those hidden in the nooks and crannies of hydrilla and other vegetation. Wilson counted fish during 13 weeks in the summers of 2011 and 2012, and then drained the ponds to obtain actual fish densities.
He conducted his research under the supervision of Micheal Allen, a professor of fisheries ecology at UF’s Institute of Food and Agricultural Sciences.
“We tested and verified the use of our camera techniques in extremely dense hydrilla habitats,” said Wilson, now a doctoral student in ecology at the University of Calgary.
The UF/IFAS study is published in the January issue of the journal Marine and Freshwater Research.
By Brad Buck, 352-294-3303, email@example.com
Sources: Kyle Wilson, 403-402-4955, firstname.lastname@example.org
Micheal Allen, 352-273-3624, email@example.com
Brad Buck | newswise
New 3-D model predicts best planting practices for farmers
26.06.2017 | Carl R. Woese Institute for Genomic Biology, University of Illinois at Urbana-Champaign
Fighting a destructive crop disease with mathematics
21.06.2017 | University of Cambridge
An international team of scientists has proposed a new multi-disciplinary approach in which an array of new technologies will allow us to map biodiversity and the risks that wildlife is facing at the scale of whole landscapes. The findings are published in Nature Ecology and Evolution. This international research is led by the Kunming Institute of Zoology from China, University of East Anglia, University of Leicester and the Leibniz Institute for Zoo and Wildlife Research.
Using a combination of satellite and ground data, the team proposes that it is now possible to map biodiversity with an accuracy that has not been previously...
Heatwaves in the Arctic, longer periods of vegetation in Europe, severe floods in West Africa – starting in 2021, scientists want to explore the emissions of the greenhouse gas methane with the German-French satellite MERLIN. This is made possible by a new robust laser system of the Fraunhofer Institute for Laser Technology ILT in Aachen, which achieves unprecedented measurement accuracy.
Methane is primarily the result of the decomposition of organic matter. The gas has a 25 times greater warming potential than carbon dioxide, but is not as...
Hydrogen is regarded as the energy source of the future: It is produced with solar power and can be used to generate heat and electricity in fuel cells. Empa researchers have now succeeded in decoding the movement of hydrogen ions in crystals – a key step towards more efficient energy conversion in the hydrogen industry of tomorrow.
As charge carriers, electrons and ions play the leading role in electrochemical energy storage devices and converters such as batteries and fuel cells. Proton...
Scientists from the Excellence Cluster Universe at the Ludwig-Maximilians-Universität Munich have establised "Cosmowebportal", a unique data centre for cosmological simulations located at the Leibniz Supercomputing Centre (LRZ) of the Bavarian Academy of Sciences. The complete results of a series of large hydrodynamical cosmological simulations are available, with data volumes typically exceeding several hundred terabytes. Scientists worldwide can interactively explore these complex simulations via a web interface and directly access the results.
With current telescopes, scientists can observe our Universe’s galaxies and galaxy clusters and their distribution along an invisible cosmic web. From the...
Temperature measurements possible even on the smallest scale / Molecular ruby for use in material sciences, biology, and medicine
Chemists at Johannes Gutenberg University Mainz (JGU) in cooperation with researchers of the German Federal Institute for Materials Research and Testing (BAM)...
19.06.2017 | Event News
13.06.2017 | Event News
13.06.2017 | Event News
26.06.2017 | Life Sciences
26.06.2017 | Physics and Astronomy
26.06.2017 | Information Technology