Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Industrial fishing threatens sharks, dolphins, billfish

05.08.2002


Industrial fishing poses the biggest threat to life and fin for sharks, dolphins and billfish that inhabit the tropical and northern Pacific Ocean, says a new study forecasting the effects of commercial fishing on ocean ecosystems.



Though not targeted by the fishing industry, some ocean species often get caught unintentionally in nets or lines used to catch tuna and other commercially valuable fish, says a study presented to scientists today, Aug. 5, at the annual meeting of the Ecological Society of America.

A University of Wisconsin-Madison group’s study points to the potential increased risks for the large, slow-growing, slow-to-reproduce animals at the top of food chain.


"It’s the sharks, dolphins and billfishes that are hurt the most," says Jefferson Hinke, a University of Wisconsin-Madison graduate student and study group member.

Now, populations of most target species are stable and viable, thanks in part to restrictions on undiscriminating fishing practices such as drift nets and fish aggregation devices. However, any substantial increase in industrial fishing could play havoc with both target and non-target animal populations, Hinke says.

"In these systems, environmental variability tends to have little effect at the top of the food web," he says. "What’s really important is the fishing."

Hinke, working under the auspices of the National Center for Ecological Analysis and Synthesis in Santa Barbara, Calif., is part of a group that is developing computer models able to accurately forecast the effects of fishing on major ocean ecosystems. The hope, he says, is to provide fishery managers with a set of tools that can be used to predict change in economically important but ecologically sensitive systems.

The models Hinke and his colleagues are working to develop can help reveal "what happens when you fish off the top of the food chain," says James Kitchell, a UW-Madison professor of zoology. "You fish in different ways, you have different effects."

In the Pacific, tuna populations - the intended and preferred catch of commercial fishing outfits from Japan, the U.S. Mexico and other Pacific nations - are in generally good shape, Hinke notes. Because these fish tend to mature and reproduce at much earlier ages than the non-target species like sharks and dolphins, their populations are able to withstand relatively heavy fishing pressure. However, increased fishing pressure would very likely cause strong declines, especially for the already very heavily fished yellowfin tuna stocks.

Other animals at that top of the ocean ecosystem heap are a different story. "Yellowfin tuna have a life span of only five years," Hinke says. "They have really fast growth rates and they can begin to reproduce early in life. A shark, on the other hand, can live 20 or 30 years and may not reproduce until it reaches 10 years of age. Sharks also produce relatively few offspring as opposed to a tuna which will spawn sometimes every day for a year and produce millions and millions of eggs."

The models being developed by Hinke and his colleagues at the National Center for Ecological Analysis and Synthesis also are meant to forecast how fish populations of all kinds will respond to different fishing scenarios. Ratcheting up fishing pressure, according to model simulations, may cause as much as a 20-50 percent decline in populations of dolphins, sharks and billfishes like marlin, sailfish and swordfish.

"The models are part of the toolbox for managers, and they have proven to be effective," Hinke says. "We can model at a level now that permits us to tell how some of these animals might respond to different levels of pressure."

Co-authors of the paper delivered by Hinke include Kitchell, who directs the UW-Madison Center for Limnology, Isaac Kaplan of the UW-Madison Center for Limnology, and George Watters, a scientist at the Pacific Fisheries Environmental Lab in Pacific Grove, Calif. Robert Olson, also a co-author, is a scientist at the Inter-American Tropical Tuna Commission in La Jolla, Calif.

CONTACT:
James Kitchell, (608) 262- 3014, kitchell@mhub.limnology.wisc.edu
Terry Devitt (608) 262-8282, trdevitt@facstaff.wisc.edu


Jefferson Hinke | EureAlert!

More articles from Ecology, The Environment and Conservation:

nachricht Joint research project on wastewater for reuse examines pond system in Namibia
19.12.2016 | Technische Universität Darmstadt

nachricht Scientists produce a new roadmap for guiding development & conservation in the Amazon
09.12.2016 | Wildlife Conservation Society

All articles from Ecology, The Environment and Conservation >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

Researchers from the University of Hamburg in Germany, in collaboration with colleagues from the University of Aarhus in Denmark, have synthesized a new superconducting material by growing a few layers of an antiferromagnetic transition-metal chalcogenide on a bismuth-based topological insulator, both being non-superconducting materials.

While superconductivity and magnetism are generally believed to be mutually exclusive, surprisingly, in this new material, superconducting correlations...

Im Focus: Studying fundamental particles in materials

Laser-driving of semimetals allows creating novel quasiparticle states within condensed matter systems and switching between different states on ultrafast time scales

Studying properties of fundamental particles in condensed matter systems is a promising approach to quantum field theory. Quasiparticles offer the opportunity...

Im Focus: Designing Architecture with Solar Building Envelopes

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...

Im Focus: How to inflate a hardened concrete shell with a weight of 80 t

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...

Im Focus: Bacterial Pac Man molecule snaps at sugar

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...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

12V, 48V, high-voltage – trends in E/E automotive architecture

10.01.2017 | Event News

2nd Conference on Non-Textual Information on 10 and 11 May 2017 in Hannover

09.01.2017 | Event News

Nothing will happen without batteries making it happen!

05.01.2017 | Event News

 
Latest News

Water - as the underlying driver of the Earth’s carbon cycle

17.01.2017 | Earth Sciences

Interfacial Superconductivity: Magnetic and superconducting order revealed simultaneously

17.01.2017 | Materials Sciences

Smart homes will “LISTEN” to your voice

17.01.2017 | Architecture and Construction

VideoLinks
B2B-VideoLinks
More VideoLinks >>>