Navigation Links
Ocean fish farming harms wild fish, study says
Date:12/15/2008

Honolulu, HIFarming of fish in ocean cages is fundamentally harmful to wild fish, according to an essay in this week's Conservation Biology.

Using basic physics, Professor Neil Frazer of the Department of Geology and Geophysics at the University of Hawaii at Manoa explains how farm fish cause nearby wild fish to decline. The foundation of his paper is that higher density of fish promotes infection, and infection lowers the fitness of the fish.

For wild fish, lowered fitness means more difficulty finding food and escaping predators, causing higher death rates. But farmed fish are not only fed, they are also protected from predators by their cage, so infected farm fish live on, shedding pathogen into the water. The higher levels of pathogen in the water cause the death rates of wild fish to rise.

The above paradigm explains recently documented declines of wild fish in areas with sea-cage farm fish.

"Sea lice are an important example of disease transfer in ocean fish farming," explains Frazer. "Sea lice are tiny crabs that attach to marine fishes, eating their skin and sometimes deeper tissue. Skin is important to fish because they need to keep their tissues less salty than the ocean. Also, when lice puncture the skin they create an entry point for other infections. So wild fish weakened by lice have more difficulty finding food and escaping predators."

A female sea louse can produce over a thousand larvae during her life. Larvae drift in the ocean and a lucky few of them drift close enough to a fish to attach. Most larvae die without ever finding a fish. In a fish farm environment, a larva's chance of finding a fish increases, so more larvae survive to become lice, and those lice put more larvae into the water. With more larvae in the water, more wild fish become infected and die as a result.

Larger numbers of lice are especially dire for salmon because juvenile salmon must transit coastal areas where salmon farms are located. Juvenile pink and chum salmon (Pacific species) suffer most because they spend much of their early life in coastal waters, and they are so small at ocean-entry that infection by even one or two lice can be fatal.

The calculations in the paper show that even if lice levels on farm fish are controlled by medication, local wild fish still decline. Also, there is a critical stocking level of farmed fish. If a sea-cage system is stocked above the critical level, local wild fish decline to extinction. Long story short growing farm fish in sea cages can't save wild fish, but it can easily destroy them.


'/>"/>

Contact: Neil Frazer
neil@soest.hawaii.edu
808-956-3724
University of Hawaii at Manoa
Source:Eurekalert  

Related biology news :

1. TAU scientists probe deep questions aboard EcoOceans environmental research ship
2. NASA celebrates a decade observing climate impacts on health of worlds oceans
3. CO2 emissions could violate EPA ocean-quality standards within decades
4. NASA celebrates a decade observing climate impacts on health of worlds oceans
5. Scientists, policymakers and industry leaders gather to discuss ocean iron fertilization
6. Acid oceans warning
7. Scientists gather in New Zealand to share oceans secrets
8. Unprecedented global measurement network achieves full coverage of oceans
9. Abel to receive posthumous Ocean and Coastal Leadership award
10. Human safety, prosperity depend on better ocean observing system: Scientists
11. Marine scientists warn human safety, prosperity depend on better ocean observing system
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Ocean fish farming harms wild fish, study says
(Date:11/15/2016)... Research and Markets has announced the addition of the ... offering. ... The global bioinformatics market is ... Billion in 2016, growing at a CAGR of 21.1% during the ... driven by the growing demand for nucleic acid and protein sequencing, ...
(Date:6/22/2016)... June 22, 2016   Acuant , ... verification solutions, has partnered with RightCrowd ® ... for Visitor Management, Self-Service Kiosks and Continuous ... that add functional enhancements to existing physical ... and venues with an automated ID verification ...
(Date:6/15/2016)... 15, 2016 Transparency Market ... Recognition Market by Application Market - Global Industry Analysis Size ... to the report, the  global gesture recognition market ... and is estimated to grow at a CAGR ... 2024.  Increasing application of gesture recognition ...
Breaking Biology News(10 mins):
(Date:11/30/2016)... , ... November 30, 2016 , ... SSCI, the established ... discuss the implications of the latest FDA guidance on pharmaceutical cocrystals as drug ... in Cambridge, MA. , The event follows the successful November 15th event ...
(Date:11/30/2016)... (PRWEB) , ... November 30, 2016 , ... ... in the development of a new orally administered treatment for Alzheimer’s disease (AD), ... results of a Phase 2a clinical trial of T3D-959 in mild to moderate ...
(Date:11/30/2016)... UK (PRWEB) , ... November 30, 2016 , ... With ... offices on Haymarket after five years and look forward to continuing their expansion in ... of Soho, an area which has been traditionally favoured by the creative industries, so ...
(Date:11/30/2016)... ... November 30, 2016 , ... Microbial genomics leader ... by Arianna Huffington, as part of the Thrive Global pop-up store. This stunning ... purchasers to explore the microorganisms in their gut, collectively known as the microbiome. ...
Breaking Biology Technology: