Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Scientists Conduct Shark Survey off U.S. East Coast

18.08.2009
More than 1,300 tagged and released to understand shark biology

Sandbar, dusky and tiger sharks are among dozens of shark species living in the coastal waters off the U.S. East Coast. Little is known about many of the species, but a survey begun nearly 25 years ago is helping scientists and fishery resource managers to monitor shark populations and their role in marine ecosystems.

NOAA scientists from the Northeast Fisheries Science Center (NEFSC) lab in Narragansett, R.I., recently conducted their ninth coastal shark survey from Florida to Delaware. The survey, conducted every two to three years, is the longest survey independent of the fishing industry of large coastal sharks in the U.S. Atlantic Ocean.

Using commercial Florida-style longline fishing methods to standardize results from survey to survey, researchers caught 1,675 sharks from 19 different species and tagged 1,352 individuals during the 2009 survey in April and May. Most of the animals caught and tagged were sandbar sharks, a common species in the western Atlantic. Longline fishing is a type of fishing that uses a long or main line with baited hooks spaced out at certain intervals along the line.

“During the survey, we often catch 19 or more species, many of which are highly migratory, and we still have a lot to learn about them,” said Nancy Kohler, who heads the Apex Predators Program at the Narragansett Lab and has been on every survey. “We do not know how large certain species are when they mature, for example. It is important that we obtain basic biological information from the fish we catch so that we can learn as much as possible about their life histories, or the changes that the animals undergo from birth to death.”

Researchers record the length, sex and location of each animal caught before the fish is tagged and released. The sharks can range from 1 foot to 15 feet; they are not weighed. Any dead fish are carefully dissected at sea, with researchers looking for parasites, collecting DNA and blood samples, and obtaining samples for studies of age and growth, reproductive biology and food habits.

The first systematic survey of Atlantic sharks was conducted by the Apex Predators Program in 1986 between Florida and southern New England waters from 5 to 200 meters deep (about 16 to 660 feet). In addition to basic biological information, researchers gather data on shark abundance and distribution and migration patterns.

Kohler said the survey is conducted in the spring because coastal shark species distributions are concentrated during this time of year since the waters north of Delaware are too cold, thus making it easier to survey the whole population. Nearly all of the surveys have been conducted from the NOAA ship Delaware II, based at the NEFSC’s Woods Hole Laboratory.

“We caught more fish and tagged more fish on this survey than any other,” said Lisa Natanson, who heads the coastal survey effort and has been on all but one of the surveys. “The previous high total was in 1998, when we caught 917 sharks and tagged 859. Some years we catch very few, so it really varies." In addition to numerous sandbar sharks, the researchers also caught one great white, many tiger and dusky sharks, and some Atlantic sharpnose. The current data are part of just one of several long-term data sets that are used to determine the health of shark populations.

The survey takes six weeks to complete and is divided into three legs, each approximately two weeks long. Eight scientists are on board for each leg, and fishing is conducted around the clock. Environmental information, such as water temperature and ocean chemistry, is obtained at each station.

Survey data are provided to the fishery managers who monitor populations in the Atlantic and Gulf of Mexico. NOAA Fisheries Service manages the commercial and recreational shark fisheries in U.S. waters, including the Caribbean Sea and the Gulf of Mexico. The United States began regulating shark fisheries in 1993 and currently manages 39 species. A fishery management plan that includes sharks, swordfish, and tunas went into effect in 1999, regulating sharks under a catch limit and quota system.

In addition to the coastal shark survey, Kohler, Natanson and colleagues in the Apex Predators Program work with thousands of volunteers throughout the Atlantic Ocean, Gulf of Mexico and the Mediterranean Sea through the Cooperative Shark Tagging Program. The lab also manages and coordinates the Cooperative Atlantic States Pupping and Nursery Survey, collaborating with researchers in coastal states from Rhode Island to Florida to conduct a comprehensive and standardized investigation of shark nursery areas.

Scientists in the program conduct life history studies of commercially and recreationally important shark species, participate in and conduct a variety of research cruises, and often go aboard commercial vessels to obtain biological samples from the catch as well as to tag sharks. Biological samples are also collected from recreational fishing tournaments in the Northeast U.S.

NOAA Fisheries Service is dedicated to protecting and preserving our nation’s living marine resources and their habitat through scientific research, management and enforcement. NOAA Fisheries Service provides effective stewardship of these resources for the benefit of the nation, supporting coastal communities that depend upon them, and helping to provide safe and healthy seafood to consumers and recreational opportunities for the American public.

NOAA understands and predicts changes in the Earth's environment, from the depths of the ocean to the surface of the sun, and conserves and manages our coastal and marine resources.

Shelley Dawicki | EurekAlert!
Further information:
http://www.noaa.gov

More articles from Ecology, The Environment and Conservation:

nachricht Bioinvasion on the rise
15.02.2017 | Universität Konstanz

nachricht Litter Levels in the Depths of the Arctic are On the Rise
10.02.2017 | Alfred-Wegener-Institut, Helmholtz-Zentrum für Polar- und Meeresforschung

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: Breakthrough with a chain of gold atoms

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

In the field of nanoscience, an international team of physicists with participants from Konstanz has achieved a breakthrough in understanding heat transport

Im Focus: DNA repair: a new letter in the cell alphabet

Results reveal how discoveries may be hidden in scientific “blind spots”

Cells need to repair damaged DNA in our genes to prevent the development of cancer and other diseases. Our cells therefore activate and send “repair-proteins”...

Im Focus: Dresdner scientists print tomorrow’s world

The Fraunhofer IWS Dresden and Technische Universität Dresden inaugurated their jointly operated Center for Additive Manufacturing Dresden (AMCD) with a festive ceremony on February 7, 2017. Scientists from various disciplines perform research on materials, additive manufacturing processes and innovative technologies, which build up components in a layer by layer process. This technology opens up new horizons for component design and combinations of functions. For example during fabrication, electrical conductors and sensors are already able to be additively manufactured into components. They provide information about stress conditions of a product during operation.

The 3D-printing technology, or additive manufacturing as it is often called, has long made the step out of scientific research laboratories into industrial...

Im Focus: Mimicking nature's cellular architectures via 3-D printing

Research offers new level of control over the structure of 3-D printed materials

Nature does amazing things with limited design materials. Grass, for example, can support its own weight, resist strong wind loads, and recover after being...

Im Focus: Three Magnetic States for Each Hole

Nanometer-scale magnetic perforated grids could create new possibilities for computing. Together with international colleagues, scientists from the Helmholtz Zentrum Dresden-Rossendorf (HZDR) have shown how a cobalt grid can be reliably programmed at room temperature. In addition they discovered that for every hole ("antidot") three magnetic states can be configured. The results have been published in the journal "Scientific Reports".

Physicist Dr. Rantej Bali from the HZDR, together with scientists from Singapore and Australia, designed a special grid structure in a thin layer of cobalt in...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Booth and panel discussion – The Lindau Nobel Laureate Meetings at the AAAS 2017 Annual Meeting

13.02.2017 | Event News

Complex Loading versus Hidden Reserves

10.02.2017 | Event News

International Conference on Crystal Growth in Freiburg

09.02.2017 | Event News

 
Latest News

Microhotplates for a smart gas sensor

22.02.2017 | Power and Electrical Engineering

Scientists unlock ability to generate new sensory hair cells

22.02.2017 | Life Sciences

Prediction: More gas-giants will be found orbiting Sun-like stars

22.02.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>