Navigation Links
Restoring fish populations leads to tough choice for Great Lakes Gulls
Date:5/14/2008

You might think that stocking the Great Lakes with things like trout and salmon would be good for the herring gull. The birds often eat from the water, so it would be natural to assume that more fish would mean better dining. But a new report published in the April journal of Ecology by the Ecological Society of America says that the addition of species such as exotic salmon and trout to the area has not been good for the birds, demonstrating that fishery management actions can sometimes have very unexpected outcomes.

Craig Hebert (National Wildlife Research Center in Ottawa, Canada) and his team analyzed 25 years of data on the gulls and found that throughout the Great Lakes region, the birds were in poor health in many areas. Tests of their fatty acids showed an increase in the type of transfat that mostly comes from food produced by humans.

It seems that the birds are being forced to make a dietary shift from fish to terrestrial food, including garbage, says Hebert.

Although no one is certain why the birds are eating more garbage, evidence points to fish stocking. When exotic salmon and trout have been added to the waters, the birds seem to be out competed for their favorite prey of smaller fish, such as alewifes.

Herring gulls, which differ from the ring necked gulls that often populate American beaches and parking lots, are by no means endangered.

But the birds have long been used as monitors of environmental conditions on the Laurentian Great Lakes. Their eggs are collected annually and analyzed for insights into how the regions food webs are changing.

Gulls are top predators in this system. When fish are unavailable, the birds turn to land instead for their foraging. When given a choice between prey fish and garbage, the birds readily chose the fish. Thus scientists assume that they only eat garbage when the prey fish numbers are low.

Prey fish in the Lake have been declining since 1980. Although multiple factors may be at play, predation by piscivorous fish appears to be the one factor that was universally important across all five Great Lakes because of massive fish stocking. The stocking was done to create recreational activities, and to reduce populations of exotic prey fish in the hope of restoring populations of native fishes.

The effects on other species that are more closely tied to the water, such as terns, may be more severe, says Hebert. Those kinds of birds can only eat fish, so their diet may be affected by this, too. They dont have the option of eating food found on land.


'/>"/>

Contact: Nadine Lymn
nadine@esa.org
202-833-8773
Ecological Society of America
Source:Eurekalert

Related biology news :

1. Window of opportunity for restoring oaks small, new study finds
2. Restoring sight, advances in fertility treatments and better visibility for pilots at FIO
3. Technique traces origins of disease genes in mixed human populations
4. The song doesnt remain the same in fragmented bird populations
5. UBC scientist invokes future generations to save tuna populations from collapse
6. Climate influence on deep sea populations
7. Fish farms drive wild salmon populations toward extinction
8. A genetic identity card for Plasmodium populations to improve control strategies
9. A study proposes a new universal rule to explain the equilibrium of plant populations
10. A study proposes a new universal rule to explain the equilibrium of plant populations
11. Concentrating on different aspects of pain leads to breakthrough in migraine genetics
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:3/23/2017)... PUNE, India , March 23, 2017 The report ... Equipment, Touchless Biometric), Industry, and Geography - Global Forecast to 2022", published by ... growing at a CAGR of 29.63% between 2017 and 2022. ... ... Logo ...
(Date:3/22/2017)... YORK , March 21, 2017 ... Marketing Cloud used by retailers such as 1-800-Flowers ... its platform — Product Recommendations and Replenishment. Using Optimove,s ... give more personalized product and replenishment recommendations to ... but also on predictions of customer intent drawn ...
(Date:3/20/2017)... March 20, 2017 PMD Healthcare announces the ... and Wellness Management System (WMS), a remote, real-time lung ... 2010, PMD Healthcare is a Medical Device, Digital Health, ... dedicated to creating innovative solutions that empower people to ... intent focus, PMD developed the first ever personal spirometer, ...
Breaking Biology News(10 mins):
(Date:4/21/2017)... , ... April 21, 2017 , ... ... dedicated to nourishing a range of emerging bio and technology start-ups, is hosting ... 21, 2017. This double event will start with libations and networking at 3:30 ...
(Date:4/20/2017)... (PRWEB) , ... April 20, 2017 , ... USDM ... for the life sciences and healthcare industries, is pleased to announce Holger Braemer ... established USDM subsidiary “USDM Europe GmbH” based in Germany. , Braemer is an ...
(Date:4/20/2017)... ... April 20, 2017 , ... Parallel6™ , the leader in mClinical™ technologies ... they were named one of the 2017 Top 10 eClinical Trial Management Solution ... pharmaceutical industry. , “We take pride in honoring Parallel6 as one of the top ...
(Date:4/19/2017)... ... , ... The Vibrating Orifice Aerosol Generator (VOAG) was developed ... of known diameters for research applications such as for calibrating droplet measuring instruments, ... droplets. , The VOAG requires forcing liquid out of an orifice about ...
Breaking Biology Technology: