Cannibalism Of The Young Allows Individual Fish To Specialize 
SW Source: Underwatertimes 5/23/2007

If you go fishing for Arctic char you may end up catching distinctly different-looking individuals although they were all caught in the same lake. Similarly, whitefish, threespine stickleback, and some sunfishes also display quite discrete groups living in the same lakes but utilizing different food resources in order to survive. The phenomenon is called resource polymorphism and has been observed and documented as early as in the 18th century, but has continued to receive a lot of scientific interest since it gives us a chance to study ongoing evolution. However, not all species display resource polymorphism, and naturally, in order to gain deeper understanding of evolutionary facilitators, the question arises: Why do some species display resource polymorphism, whereas other don't?
 

In this study, a team of European researchers combines literature data and advanced ecological theory in order to look for species-specific life history patterns explaining the presence/absence of resource polymorphism in fish. Interestingly and not at all obvious, the study suggests that early cannibalism, which is found in all species displaying resource polymorphism, is a promoting factor. However, incorporating recently explored and presented population dynamic theory, based upon the population's size distribution and the effect of the individual's size on its relative competitiveness, a logic explanation is given. The effect of early cannibalism is twofold. First, it stabilizes the variation in the number of individuals over time, which in turn increases the benefit of specializing on any resource since the risk of being dependent on a vanishing resource decreases. Second, an early disappearance of small newborn individuals increases the abundance of their prey due to decreased consumption from the small ones, hence increasing the benefit for larger individuals to specialize on this specific prey (typically zooplankton). The team now plans to do new modeling exercises and practical experiments in order to further explore the suggested hypothesis.

 
Char, Arctic Continue...

News Id SourceStampcountry
5276Un pez muerde a una mujer en una playa de Elche y le secciona el tendón del pieEl Mundo2019-08-08ES
5277Government collaboration questioned in dead fish investigationCBC News2019-08-09CA
5278Россиянам станет сложнее рыбачитьlenta2019-08-09RU
5279US fish stocks at sustainable levels at near record-highSaipan Tribune2019-08-08US
5280Time of essence as Fraser River slide blocks spawning salmonCBC2019-08-06CA
5281К берегам России впервые приплыл сельдяной корольРИА Новости2019-08-08RU
5282Why Triathletes Should Be Fierce Advocates for Clean Watertriathlete2019-08-02CA
5283Expert raises doubt about cause of fish deaths near Ottawa this summerToronto Star2019-08-07CA
5284Giant 'GOLDFISH' found in US lake is actually '100-year-old' mutant bigmouth buffalo weighing 32 poundsdailymail2019-06-21US
5285The Oldest Freshwater Fish Ever Found Just Changed What We Know About Fishscience alert2019-08-05US
5286Kentucky team zaps dozens of jumping Asian carp in electrofishing testGlobal News2019-08-02US
5287Angler breaks longstanding record with mahi mahiusatoday2019-07-31US
5288Angler lands 946-pound marlin by himself for ‘historic catch’usatoday2019-07-31US
5289A demand for answers after more dead fish wash up in GatineauCBC News2019-08-01CA
5290Officials may soon install salmon ladders to help fish blocked by B.C. landslideGlobal News2019-07-31CA
5291Man dies after contracting ‘brain-eating amoeba’ at North Carolina water parkThe Associated Press2019-07-27US
5292Ontario Ministry of Natural Resources creates 250 new hunting and fishing fines, doubles 50 othersCBC News2019-07-23CA
5293More dead fish found in Ottawa and Lièvre riversOttawa Citizen2019-07-21CA
5294CARPER Nick Royce had the battle of his life when he landed this lake record catfish estimated at over 130 lb.Angler's Mail2019-07-12UK
5295Angler defies odds, lands truly enormous halibutUSA TODAY2019-07-18NO
5296Muriel Lake on the riseBonnyville Nouvelle2016-07-19CA
5297Disappearing Muriel Lake worrying nearby residentsCBC News2014-05-30CA
5298Invasive fish species makes its way into Rideau CanalGlobal News2019-07-16CA
5299Atlantic salmon population being monitored in the Stewiacke RiverTruro News2015-06-17CA
5300Fishing, across generations, near the proposed Alton Gas site in Nova ScotiaThe Chronicle Herald2019-04-26CA

214 215 216 211 of [217 - pages.]