Navigation Links
Jellyfish dominate fish in over-harvested Namibian waters

By sampling sea life in a heavily fished region off the coast of Namibia, researchers have found that jellyfish have actually overtaken fish in terms of the biomass they contribute to this ocean region. The findings represent a careful quantitative analysis of what's been called a "jellyfish explosion" after intense fishing in the area in the last few decades. The findings are reported by Andrew Brierley, of the University of St. Andrews, and his colleagues in the July 12th issue of the journal Current Biology.

An increasing abundance of jellyfish off Namibia had been noted for some time, but an analysis of this trend's effect on the ecosystem has been hampered by a lack of hard data on jellyfish abundance. The authors note that prior to their work, less formal observations had pointed to a striking change over time--for example, jellyfish are now so numerous in the region that they significantly interfere with fishing operations and industrial water-uptake systems. In addition, large jellyfish species such as Chrysaora hysoscella and Aequorea forskalea have become more commonly reported.

In their new work, the researchers sampled waters all along the Namibian shelf, between the borders of Angola and South Africa, in an area known as the northern Benguela. In the past, this region has offered abundant fish stocks, thanks largely to its being served by cool, nutrient-rich upwellings occuring along the continental shelf. The fish stocks, including sardines and anchovies, have been heavily exploited since the 1970s and have been strongly depleted in the process. Because fish and jellyfish essentially compete for similar nutrient resources, a dramatic decline in fish populations could theoretically contribute to a substantial shift in the abundance of jellyfish.

The researchers' findings indicate that jellyfish now account for significantly more biomass in the northern Benguela waters than do fish. Based on the data they obtained--by using sc ientific echosounders and trawl nets to sample jellyfish and fish in an area of over 30,000 nautical miles--the researchers estimate the total biomass of jellyfish in the region to be 12.2 million metric tons (mostly contributed by the large A. forskalea species), whereas the biomass of fish accounts for only 3.6 million metric tons.

In their report, the authors point out that jellyfish biomass has risen in numerous locations worldwide, possibly as a consequence of fishing. Climactic changes could also contribute to jellyfish population shifts.

The authors also note that jellyfish have few predators and that jellyfish abundance has significant potential consequences for oceanic ecosystems--such consequences include slowed or attenuated fish-stock recovery and alterations in the nature of carbon cycling.


'"/>

Source:Cell Press


Related biology news :

1. Survey finds silver contamination in North Pacific waters
2. Detecting microalgae in coastal waters
3. How fish species suffer as a result of warmer waters
Post Your Comments:
*Name:
*Comment:
*Email:


(Date:6/22/2016)... 2016  The American College of Medical Genetics and Genomics ... as one of the fastest-growing trade shows during the ... Bellagio in Las Vegas . ... growth in each of the following categories: net square feet ... of attendees. The 2015 ACMG Annual Meeting was ranked 23 ...
(Date:6/16/2016)... June 16, 2016 The ... expected to reach USD 1.83 billion by 2024, ... Research, Inc. Technological proliferation and increasing demand in ... expected to drive the market growth. ... The development of advanced multimodal techniques for ...
(Date:6/3/2016)... 2016 Das DOTM ... Nepal hat ein 44 Millionen ... Kennzeichen, einschließlich Personalisierung, Registrierung und IT-Infrastruktur, an ... und Implementierung von Identitätsmanagementlösungen. Zahlreiche renommierte internationale ... teilgenommen, aber Decatur wurde als konformste und ...
Breaking Biology News(10 mins):
(Date:6/23/2016)... June 23, 2016 Houston Methodist Willowbrook ... Cy-Fair Sports Association to serve as their official ... Houston Methodist Willowbrook will provide sponsorship support, athletic ... with association coaches, volunteers, athletes and families. ... Cy-Fair Sports Association and to bring Houston Methodist ...
(Date:6/23/2016)... , June 23, 2016  The Prostate Cancer Foundation (PCF) is ... treatments and faster cures for prostate cancer. Members of the Class of 2016 ... countries. Read More About the Class of 2016 PCF ... ... ...
(Date:6/23/2016)... 2016   EpiBiome , a precision microbiome engineering ... debt financing from Silicon Valley Bank (SVB). The financing ... advance its drug development efforts, as well as purchase ... "SVB has been an incredible strategic partner to us ... bank would provide," said Dr. Aeron Tynes Hammack ...
(Date:6/23/2016)... OTTAWA, ON (PRWEB) , ... June 23, 2016 , ... ... former DNA Technical Leader at the Arkansas State Crime Laboratory, has joined STACS DNA ... joining the STACS DNA team,” said Jocelyn Tremblay, President and COO of STACS DNA. ...
Breaking Biology Technology: