Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Abundance of a look-alike species clouds population status of a million dollar fish

11.12.2009
New findings cast uncertainty on previous population size assessments for the severely overfished white marlin and call for reassessment of international recovery efforts

The prized white marlin, sought by anglers in million dollar prize tournaments and captured incidentally in commercial fisheries, is among the most overfished marine species under international management and the subject of contentious debate on how to best achieve its recovery.

Now a new study published today in the journal Endangered Species Research casts uncertainty on the accuracy of current knowledge of white marlin biology and previous population assessments, which form the basis of management and conservation policy. The study reports that the white marlin look-alike species, the enigmatic roundscale spearfish – whose very existence was only confirmed three years ago – makes up almost a third (approximately 27%) of the fish historically identified as white marlin.

This previously unrealized, relatively high abundance of roundscale spearfish and their misidentification might have impacted past assessments of white marlin population sizes and concomitant management efforts.

Given considerable concern about its declining populations, petitions to list the white marlin under the U.S. Endangered Species Act were considered in 2002 and 2007. Listing the fish would have undoubtedly put an end to white marlin fishing tournaments, which infuse millions of dollars into the recreational fishing industry as well as local economies.

"This proportion of roundscale spearfish along with its longstanding misidentification as white marlin for decades compromises the accuracy of current biological knowledge on white marlin" said lead author Lawrence Beerkircher of the NOAA Fisheries Service. "These findings illustrate a need for the immediate collection of biological and fishery data such as age and growth, migratory patterns, and fishery catch statistics for both the real white marlin and the roundscale spearfish."

To examine if the high proportion of roundscale spearfish and its misidentification might have impacted past assessments of white marlin population sizes, the research team conducted computer simulation studies which calculated historical population size trends for each species individually. Since the past ratios of roundscale spearfish to white marlin are unknown, the researchers also examined how variations in these ratios would impact the projections of population size trends for each species. The results of these computer simulations illustrated that variations in the ratio of the two species could indeed alter projections of white marlin population sizes, highlighting the influence that species misidentifications could have on the accuracy of past assessments.

For example, the most recent population assessment conducted by the International Convention for the Conservation of Atlantic Tunas (ICCAT) for white marlin in 2006 indicated a slight increasing trend in its population sizes, which was one of several reasons for its removal from the National Oceanic and Atmospheric Administration's (NOAA) Species of Concern List. However, based on the computer simulations conducted in the new study, whether this was, or was not, the right call cannot be determined without a breakdown of the two species ratios over time.

"It's remarkable how a simple case of mistaken identity can muddy what we thought we knew about a species from decades of study. This case points to the importance of making sure we know what species are out there in the first place", said Mahmood Shivji, Director of the Guy Harvey Research Institute at Nova Southeastern University, who co-led the study. "Furthermore, it's important to realize that we are also dealing with the existence of another large oceanic species, the roundscale spearfish, about which we know almost nothing and whose populations may be declining, steady or even on the rise"

"Obtaining a robust picture of white marlin population status will require conducting population assessments with updated roundscale spearfish proportions", said Lawrence Beerkircher. "New species-specific monitoring measures will be essential for achieving this goal and aiding rebuilding of white marlin populations."

NOAA Fisheries Service's Southeast Fisheries Science Center conducts multi-disciplinary research programs to provide management information to support national and regional programs of NMFS; and to respond to the needs of Regional Fishery Management Councils, Interstate and International Fishery Commission, Fishery Development Foundations, government agencies, and the general public. The SEFSC website is: http://www.sefsc.noaa.gov/.

The Guy Harvey Research Institute at Nova Southeastern University, Florida, conducts basic and applied scientific research needed for effective conservation, biodiversity maintenance and understanding of the world's wild fishes. For more information, please visit http://www.nova.edu/ocean/ghri.

Ken Ma | EurekAlert!
Further information:
http://www.nova.edu

More articles from Life Sciences:

nachricht Navigational view of the brain thanks to powerful X-rays
18.10.2017 | Georgia Institute of Technology

nachricht Separating methane and CO2 will become more efficient
18.10.2017 | KU Leuven

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Neutron star merger directly observed for the first time

University of Maryland researchers contribute to historic detection of gravitational waves and light created by event

On August 17, 2017, at 12:41:04 UTC, scientists made the first direct observation of a merger between two neutron stars--the dense, collapsed cores that remain...

Im Focus: Breaking: the first light from two neutron stars merging

Seven new papers describe the first-ever detection of light from a gravitational wave source. The event, caused by two neutron stars colliding and merging together, was dubbed GW170817 because it sent ripples through space-time that reached Earth on 2017 August 17. Around the world, hundreds of excited astronomers mobilized quickly and were able to observe the event using numerous telescopes, providing a wealth of new data.

Previous detections of gravitational waves have all involved the merger of two black holes, a feat that won the 2017 Nobel Prize in Physics earlier this month....

Im Focus: Smart sensors for efficient processes

Material defects in end products can quickly result in failures in many areas of industry, and have a massive impact on the safe use of their products. This is why, in the field of quality assurance, intelligent, nondestructive sensor systems play a key role. They allow testing components and parts in a rapid and cost-efficient manner without destroying the actual product or changing its surface. Experts from the Fraunhofer IZFP in Saarbrücken will be presenting two exhibits at the Blechexpo in Stuttgart from 7–10 November 2017 that allow fast, reliable, and automated characterization of materials and detection of defects (Hall 5, Booth 5306).

When quality testing uses time-consuming destructive test methods, it can result in enormous costs due to damaging or destroying the products. And given that...

Im Focus: Cold molecules on collision course

Using a new cooling technique MPQ scientists succeed at observing collisions in a dense beam of cold and slow dipolar molecules.

How do chemical reactions proceed at extremely low temperatures? The answer requires the investigation of molecular samples that are cold, dense, and slow at...

Im Focus: Shrinking the proton again!

Scientists from the Max Planck Institute of Quantum Optics, using high precision laser spectroscopy of atomic hydrogen, confirm the surprisingly small value of the proton radius determined from muonic hydrogen.

It was one of the breakthroughs of the year 2010: Laser spectroscopy of muonic hydrogen resulted in a value for the proton charge radius that was significantly...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

ASEAN Member States discuss the future role of renewable energy

17.10.2017 | Event News

World Health Summit 2017: International experts set the course for the future of Global Health

10.10.2017 | Event News

Climate Engineering Conference 2017 Opens in Berlin

10.10.2017 | Event News

 
Latest News

Osaka university researchers make the slipperiest surfaces adhesive

18.10.2017 | Materials Sciences

Space radiation won't stop NASA's human exploration

18.10.2017 | Physics and Astronomy

Los Alamos researchers and supercomputers help interpret the latest LIGO findings

18.10.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>