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 Zebrafish's near 360 degree UV-vision knocks stripes off Google Street View
22.06.2018 | University of Sussex

nachricht New cellular pathway helps explain how inflammation leads to artery disease
22.06.2018 | Cedars-Sinai Medical Center

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

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

Im Focus: Temperature-controlled fiber-optic light source with liquid core

In a recent publication in the renowned journal Optica, scientists of Leibniz-Institute of Photonic Technology (Leibniz IPHT) in Jena showed that they can accurately control the optical properties of liquid-core fiber lasers and therefore their spectral band width by temperature and pressure tuning.

Already last year, the researchers provided experimental proof of a new dynamic of hybrid solitons– temporally and spectrally stationary light waves resulting...

Im Focus: Overdosing on Calcium

Nano crystals impact stem cell fate during bone formation

Scientists from the University of Freiburg and the University of Basel identified a master regulator for bone regeneration. Prasad Shastri, Professor of...

Im Focus: AchemAsia 2019 will take place in Shanghai

Moving into its fourth decade, AchemAsia is setting out for new horizons: The International Expo and Innovation Forum for Sustainable Chemical Production will take place from 21-23 May 2019 in Shanghai, China. With an updated event profile, the eleventh edition focusses on topics that are especially relevant for the Chinese process industry, putting a strong emphasis on sustainability and innovation.

Founded in 1989 as a spin-off of ACHEMA to cater to the needs of China’s then developing industry, AchemAsia has since grown into a platform where the latest...

Im Focus: First real-time test of Li-Fi utilization for the industrial Internet of Things

The BMBF-funded OWICELLS project was successfully completed with a final presentation at the BMW plant in Munich. The presentation demonstrated a Li-Fi communication with a mobile robot, while the robot carried out usual production processes (welding, moving and testing parts) in a 5x5m² production cell. The robust, optical wireless transmission is based on spatial diversity; in other words, data is sent and received simultaneously by several LEDs and several photodiodes. The system can transmit data at more than 100 Mbit/s and five milliseconds latency.

Modern production technologies in the automobile industry must become more flexible in order to fulfil individual customer requirements.

Im Focus: Sharp images with flexible fibers

An international team of scientists has discovered a new way to transfer image information through multimodal fibers with almost no distortion - even if the fiber is bent. The results of the study, to which scientist from the Leibniz-Institute of Photonic Technology Jena (Leibniz IPHT) contributed, were published on 6thJune in the highly-cited journal Physical Review Letters.

Endoscopes allow doctors to see into a patient’s body like through a keyhole. Typically, the images are transmitted via a bundle of several hundreds of optical...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

Munich conference on asteroid detection, tracking and defense

13.06.2018 | Event News

2nd International Baltic Earth Conference in Denmark: “The Baltic Sea region in Transition”

08.06.2018 | Event News

ISEKI_Food 2018: Conference with Holistic View of Food Production

05.06.2018 | Event News

 
Latest News

Graphene assembled film shows higher thermal conductivity than graphite film

22.06.2018 | Materials Sciences

Fast rising bedrock below West Antarctica reveals an extremely fluid Earth mantle

22.06.2018 | Earth Sciences

Zebrafish's near 360 degree UV-vision knocks stripes off Google Street View

22.06.2018 | Life Sciences

VideoLinks
Science & Research
Overview of more VideoLinks >>>