Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Longer catch-and-release time leaves largemouth bass nests more vulnerable to predators

08.04.2014

During spawning season, a largemouth bass male attentively guards its nest.

Recent research at the University of Illinois found that catch-and-release angling could give bass predators the perfect opportunity to consume the young. In fact, the time spent away from the nest during a catch-and-release event and the subsequent exhaustion it creates for the male are critical to the survival of the embryos, particularly in lakes with high densities of brood predators.


This image shows bass underwater.

Credit: University of Illinois

"One of the main conclusions of the study was that in a lake where there are very few brood predators, when you angle a male away from his nest and then immediately release him, the chance of a negative impact is less, but if the nest is located in a part of a lake where there is a high density of brood predators, once the male is removed, predators get into the nest very quickly," said U of I fisheries research scientist Jeff Stein.

"On average, the time it took brood predators to begin eating bass young was less than five minutes in cases where the nest was located near schools of brood predators."

Stein said that the message to anglers is, if they are catch-and-release angling for nesting bass early in the year, it's best if they can get the fish back into the water as soon as possible, especially if the lake is known to have a high density of largemouth bass predators such as bluegill, pumpkinseed, or rock bass.

In the study, 70 nests were located within nine lakes in southeastern Ontario and southwestern Quebec, which were closed to public angling during the data collection period. All of the lakes contained natural largemouth bass populations, with varying numbers of known brood predators. Stein snorkeled in shallow water wearing a neoprene wetsuit that provided buoyancy to float for hours at a time. He observed the nests and assigned scores representing the number of brood predators and the quality of parental care demonstrated by the largemouth bass dads. (The female leaves immediately after laying the eggs and has absolutely no part in parental care of the nest. The males defend the nests from predators.)

Nesting males were captured and held in a live well for 15 minutes, then released – but took another 30 minutes on average to return to their nests. Stein put that return time into perspective by comparing catch-and-release practices for both professional and amateur anglers. "A pro who isn't interested in anything about the fish other than that he caught it will rip that fish over in about 15 seconds into the boat and spend only about another minute or two with the fish before releasing it back into the water," Stein said. "Casual recreational anglers may be afraid they're going to lose the catch and so may play it a little more, which exhausts the fish more. After the fish is caught, it might accidentally flop around on the floor of the boat for a while. They may put it in a live well if they're thinking of keeping it or until they get the camera out. Five minutes or more elapse."

Stein said that by the time the fish is finally released back into the water it's tired and stressed. He compared the fishes' exhaustion to a runner in a marathon being told to hold his breath at the finish line.

When "dads" are released back into the water, they don't head right back to the nest. "They're disoriented so they go to the bottom to sit and recover for a while and get their heart rate back to stasis," Stein said. "The fish is saying, 'Okay, I lived through whatever that was. Now where is my nest?' and by the time it actually gets back to the nest it has been gone from it 30 minutes."

Because bass typically spawn only one time per year when the water temperature reaches a critical threshold, it's doubtful that the male will spawn a second time if it loses its eggs to a predator. This means that, in places that have a high density of brood predators, catch-and-release, particularly during spawning season, could result in a reduction of the bass population.

The bass population is also affected by how many broods are actually captured each year. "In a lake with 100 bass nests but very little angling pressure and not many predators, one, two, or three nests where the male gets captured and the nest is raided won't make a big difference in the overall population flow because most of the first-year young are going to survive," Stein said. "But in a smaller lake with lots of bluegill and lots of anglers throughout the spawning season—that scenario could affect the next generation of bass."

Fishing spawning beds for bass is a known strategy among knowledgeable anglers, Stein said "During spawning season, the males are highly aggressive and the females are big because they're full of eggs ready to spawn. Some jurisdictions, some provinces, and states in North America disallow any fishing for bass or require catch-and-release angling during the spawning season," he said. "Illinois has a regulation for streams that prohibits harvesting smallmouth bass from April 1 to June 15 to encourage a successful spawn."

"I could envision a future where regionally or in specific lakes in which we know some bass populations may be at risk because of the presence of large numbers of brood predators and angling pressure is really high, that management would track these ingredients that can have a high negative impact on the bass population," Stein said. He added that in some areas of Ontario, for example, bass fishing doesn't open until the fourth weekend in June.

"We definitely know that the success rate of largemouth bass nests when parental care is interrupted is lower," Stein said. "During catch-and-release angling, the male may become so physically taxed that it doesn't continue parental care. The big question we're still looking at is how it affects the whole population."

###

Stein is a senior research scientist with the Illinois State Natural History Survey, which is part of the Prairie Research Institute at the University of Illinois, and is an adjunct professor in the College of Agricultural, Consumer and Environmental Sciences' Department of Natural Resources and Environmental Sciences.

"Quantifying brood predation in largemouth bass (Micropterus salmoides) associated with catch-and-release angling of nesting males," co-authored by David Philipp, was published in a recent issue of Environmental Biology of Fishes. Partial funding was provided by the Federal Aid in Sport Fish Restoration Project F-69-R and by the Ron Ward Scholarship from the Champaign-Urbana Bass Club.

Debra Levey Larson | EurekAlert!
Further information:
http://www.illinois.edu

Further reports about: Agricultural Environmental bluegill eggs exhaustion nests

More articles from Life Sciences:

nachricht Study shines light on brain cells that coordinate movement
26.06.2017 | University of Washington Health Sciences/UW Medicine

nachricht New insight into a central biological dogma on ion transport
26.06.2017 | Aarhus University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Can we see monkeys from space? Emerging technologies to map biodiversity

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...

Im Focus: Climate satellite: Tracking methane with robust laser technology

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...

Im Focus: How protons move through a fuel cell

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...

Im Focus: A unique data centre for cosmological simulations

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...

Im Focus: Scientists develop molecular thermometer for contactless measurement using infrared light

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)...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Plants are networkers

19.06.2017 | Event News

Digital Survival Training for Executives

13.06.2017 | Event News

Global Learning Council Summit 2017

13.06.2017 | Event News

 
Latest News

Study shines light on brain cells that coordinate movement

26.06.2017 | Life Sciences

Smooth propagation of spin waves using gold

26.06.2017 | Physics and Astronomy

Switchable DNA mini-machines store information

26.06.2017 | Information Technology

VideoLinks
B2B-VideoLinks
More VideoLinks >>>