Scientists suspect that tilapia introduced to the waterways of the Fiji Islands may be gobbling up the larvae and juvenile fish of several native species of goby, fish that live in both fresh and salt water and begin their lives in island streams.
The recently published paper appears in Aquatic Conservation: Marine and Freshwater Ecosystems. The authors include: Stacy Jupiter and Ingrid Qauqau of the Wildlife Conservation Society; Aaron P. Jenkins of Wetlands International-Oceania; and James Atherton of Conservation International.
"Many of the unique freshwater fishes of the Fiji Islands are being threatened by introduced tilapia and other forms of development in key water catchment basins," said Dr. Jupiter, a co-author of the study and one of the investigators examining the effects of human activities on the native fauna. "Conserving the native fishes of the islands will require a multi-faceted collaboration that protects not only the waterways of the islands, but the ecosystems that contain them."
The most surprising finding of the study centers on the tilapia, a member of the cichlid family of fishes from Africa that has become one of the most important kinds of fish for aquaculture, due in large part to its rapid rate of growth and palatability. Aside from its value as a source of protein, the tilapia is sometimes problematic to native fish species in tropical locations.
To gauge the impacts of tilapia and other human activities on native fish species in the Fiji Archipelago, researchers surveyed the fish species and other denizens of 20 river basins on the major islands of Vitu Levu, Vanua Levu, and Taveuni. In addition to catching and identifying fishes with gill and seine nets, the scientists also rated other environmental factors such as: the potential of erosion due to loss of forest cover and riparian vegetation; road density near rivers and streams; the distances and complexity of nearby mangroves and reefs; and the presence or absence of invasive species (tilapia mainly).
The team found that streams with tilapia contained 11 fewer species of native fishes than those without; species most sensitive to introduced tilapia included the throat-spine gudgeon, the olive flathead-gudgeon, and other gobies. In general, sites where tilapia were absent had more species of native fish.
Since tilapia are known to consume the larvae and juvenile fish, the researchers assume that the introduced species may be consuming the native ones as they make their way upstream and down. Absence of forest cover adjacent to streams was also correlated to fewer fish species.
Based on the spatial information compiled in the study, the researchers found that remote and undeveloped regions—with waterways containing a full complement of native species and no tilapia—on the three islands should be considered priority locations for management. The main management activities, the authors recommend, should include conserving forests around waterways and keeping the tilapia out.
"Protecting marine and aquatic biodiversity takes more than managing isolated rivers or coral reefs," said Dr. Caleb McClennen, Director of the Wildlife Conservation Society's Marine Program. "A holistic conservation approach is needed, one that incorporates freshwater systems, the surrounding forest cover, coastal estuaries and seaward coral reefs. As aquaculture continues to develop worldwide, best practices must include precautionary measures to keep farmed species out of the surrounding natural environment."
John Delaney | EurekAlert!
Joint research project on wastewater for reuse examines pond system in Namibia
19.12.2016 | Technische Universität Darmstadt
Scientists produce a new roadmap for guiding development & conservation in the Amazon
09.12.2016 | Wildlife Conservation Society
Among the general public, solar thermal energy is currently associated with dark blue, rectangular collectors on building roofs. Technologies are needed for aesthetically high quality architecture which offer the architect more room for manoeuvre when it comes to low- and plus-energy buildings. With the “ArKol” project, researchers at Fraunhofer ISE together with partners are currently developing two façade collectors for solar thermal energy generation, which permit a high degree of design flexibility: a strip collector for opaque façade sections and a solar thermal blind for transparent sections. The current state of the two developments will be presented at the BAU 2017 trade fair.
As part of the “ArKol – development of architecturally highly integrated façade collectors with heat pipes” project, Fraunhofer ISE together with its partners...
At TU Wien, an alternative for resource intensive formwork for the construction of concrete domes was developed. It is now used in a test dome for the Austrian Federal Railways Infrastructure (ÖBB Infrastruktur).
Concrete shells are efficient structures, but not very resource efficient. The formwork for the construction of concrete domes alone requires a high amount of...
Many pathogens use certain sugar compounds from their host to help conceal themselves against the immune system. Scientists at the University of Bonn have now, in cooperation with researchers at the University of York in the United Kingdom, analyzed the dynamics of a bacterial molecule that is involved in this process. They demonstrate that the protein grabs onto the sugar molecule with a Pac Man-like chewing motion and holds it until it can be used. Their results could help design therapeutics that could make the protein poorer at grabbing and holding and hence compromise the pathogen in the host. The study has now been published in “Biophysical Journal”.
The cells of the mouth, nose and intestinal mucosa produce large quantities of a chemical called sialic acid. Many bacteria possess a special transport system...
UMD, NOAA collaboration demonstrates suitability of in-orbit datasets for weather satellite calibration
"Traffic and weather, together on the hour!" blasts your local radio station, while your smartphone knows the weather halfway across the world. A network of...
Fiber-reinforced plastics (FRP) are frequently used in the aeronautic and automobile industry. However, the repair of workpieces made of these composite materials is often less profitable than exchanging the part. In order to increase the lifetime of FRP parts and to make them more eco-efficient, the Laser Zentrum Hannover e.V. (LZH) and the Apodius GmbH want to combine a new measuring device for fiber layer orientation with an innovative laser-based repair process.
Defects in FRP pieces may be production or operation-related. Whether or not repair is cost-effective depends on the geometry of the defective area, the tools...
10.01.2017 | Event News
09.01.2017 | Event News
05.01.2017 | Event News
16.01.2017 | Power and Electrical Engineering
16.01.2017 | Information Technology
16.01.2017 | Power and Electrical Engineering