Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

UH SOEST and Hawai'i DAR provide new understanding of rare white shark movement around Hawai'i

19.04.2013
A study just published in the Journal of Marine Biology sheds new light on the relatively rare but occasionally recorded presence of white sharks in waters surrounding the Hawaiian Islands, and suggests a new method to help distinguish between white sharks and close relatives, such as mako sharks.

The paper, titled "Occurrence of White Sharks in Hawaiian Waters", was written by Kevin Weng of the University of Hawai'i – Manoa's School of Ocean and Earth Science and Technology (SOEST) and Randy Honebrink of the Hawai'i DLNR Division of Aquatic Resources (DAR).


This is a white shark in water near Guadalupe, Mexico, which is one of the source areas for sharks that visit Hawai'i. Credit: Kevin Weng, UHM.

According to William Aila, chairperson of the State of Hawai'i Department of Land and Natural Resources, "This study is valuable in that it provides a better understanding of the biology and behavior of white sharks, which is very useful for management purposes. White sharks were caught by pre-contact Hawaiians, and their teeth used in weapons and other implements. But in many ways they continue to mystify us today."

Satellite tracking studies have previously shown that Hawai'i's white sharks are migrants from population centers off California and Mexico. A relatively small proportion of those West Coast sharks migrate all the way to Hawai'i, which is why they are so rarely seen.

The authors reviewed all available sources of information relating to white sharks in Hawai'i, including newspaper accounts of shark attacks, shark control program catch records, photos and videos from various sources, and satellite tracking data. Only data that could be confirmed as pertaining to white sharks was included in the analysis. In cases where information was insufficient for positive species identification, the sightings were eliminated.

According to Dr. Weng, "We learned that white sharks occur in Hawai'i across a broader part of the annual cycle than previously thought – we recorded observations from every month except November. This is important for our understanding of white shark life history and population."

Since all records of white sharks in Hawaiian waters are of individuals larger than 3.3 meters (10.8 feet), and no juveniles have ever been reported, there is no evidence of white sharks being residents or pupping here.

Scientists have learned a great deal about the migratory patterns of white sharks in the Eastern Pacific since the advent of satellite tracking, but important questions remain. "Our satellite tracking studies have been conducted in places where we can get very close to the animals – seal colonies – but this means that we may be sampling a subset of the population, and thus obtaining biased results," said Weng. "It is possible that there are individuals that do not aggregate around seal colonies."

"Male and female white sharks have different migration patterns," explained Weng. "Males have been recorded in Hawai'i from December through June, but females have been observed here all year round." Female white shark visits to Hawai'i may be related to a two-year reproductive cycle, in which they return to coastal aggregation sites off California and Mexico on alternating years. That leaves them with more time to spend in Hawai'i, where warmer water temperatures may speed up fetal development. Our results are consistent with a very recent paper by Domeier and Nasby-Lucas in the journal Animal Biotelemetry.

Misidentification of similar looking sharks, such as makos, has been a recurring problem. A recent example was the sighting of a shortfin mako shark off Ka'ena Point, O'ahu, on Jan. 12, 2012. This sighting, captured on a video that "went viral," was reported around the world as a white shark by the news media, an error that continues to this day.

This study proposes a simple method to help distinguish between the two species based on the shape of the head. Mako sharks have a more acute head shape than white sharks. Since many sightings only obtain photographs of the head, this method should be helpful for situations with limited information and no specimen.

Dr. Kevin Weng will be available for interviews today, April 18, from 10 am – 12 pm on UHM campus. Please call to arrange a meeting.

K Weng and R Honebrink, Journal of Marine Biology Volume 2013 (2013), Article ID 598745, http://dx.doi.org/10.1155/2013/598745. Supplementary Material available here: http://www.hindawi.com/journals/jmb/2013/598745/sup/

Copyright © 2013 Kevin Weng and Randy Honebrink. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.

More information on this research can be found here: http://www.soest.hawaii.edu/oceanography/faculty/kweng/kweng_lab/Hawaii

_white_sharks.html

Marcie Grabowski | EurekAlert!
Further information:
http://www.hawaii.edu

More articles from Ecology, The Environment and Conservation:

nachricht Deep decarbonization of industry is possible with innovations
25.03.2019 | Fraunhofer-Institut für System- und Innovationsforschung (ISI)

nachricht Five-point plan to integrate recreational fishers into fisheries and nature conservation policy
20.03.2019 | Leibniz-Institut für Gewässerökologie und Binnenfischerei (IGB)

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: The taming of the light screw

DESY and MPSD scientists create high-order harmonics from solids with controlled polarization states, taking advantage of both crystal symmetry and attosecond electronic dynamics. The newly demonstrated technique might find intriguing applications in petahertz electronics and for spectroscopic studies of novel quantum materials.

The nonlinear process of high-order harmonic generation (HHG) in gases is one of the cornerstones of attosecond science (an attosecond is a billionth of a...

Im Focus: Magnetic micro-boats

Nano- and microtechnology are promising candidates not only for medical applications such as drug delivery but also for the creation of little robots or flexible integrated sensors. Scientists from the Max Planck Institute for Polymer Research (MPI-P) have created magnetic microparticles, with a newly developed method, that could pave the way for building micro-motors or guiding drugs in the human body to a target, like a tumor. The preparation of such structures as well as their remote-control can be regulated using magnetic fields and therefore can find application in an array of domains.

The magnetic properties of a material control how this material responds to the presence of a magnetic field. Iron oxide is the main component of rust but also...

Im Focus: Self-healing coating made of corn starch makes small scratches disappear through heat

Due to the special arrangement of its molecules, a new coating made of corn starch is able to repair small scratches by itself through heat: The cross-linking via ring-shaped molecules makes the material mobile, so that it compensates for the scratches and these disappear again.

Superficial micro-scratches on the car body or on other high-gloss surfaces are harmless, but annoying. Especially in the luxury segment such surfaces are...

Im Focus: Stellar cartography

The Potsdam Echelle Polarimetric and Spectroscopic Instrument (PEPSI) at the Large Binocular Telescope (LBT) in Arizona released its first image of the surface magnetic field of another star. In a paper in the European journal Astronomy & Astrophysics, the PEPSI team presents a Zeeman- Doppler-Image of the surface of the magnetically active star II Pegasi.

A special technique allows astronomers to resolve the surfaces of faraway stars. Those are otherwise only seen as point sources, even in the largest telescopes...

Im Focus: Heading towards a tsunami of light

Researchers at Chalmers University of Technology and the University of Gothenburg, Sweden, have proposed a way to create a completely new source of radiation. Ultra-intense light pulses consist of the motion of a single wave and can be described as a tsunami of light. The strong wave can be used to study interactions between matter and light in a unique way. Their research is now published in the scientific journal Physical Review Letters.

"This source of radiation lets us look at reality through a new angle - it is like twisting a mirror and discovering something completely different," says...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

VideoLinks
Industry & Economy
Event News

International Modelica Conference with 330 visitors from 21 countries at OTH Regensburg

11.03.2019 | Event News

Selection Completed: 580 Young Scientists from 88 Countries at the Lindau Nobel Laureate Meeting

01.03.2019 | Event News

LightMAT 2019 – 3rd International Conference on Light Materials – Science and Technology

28.02.2019 | Event News

 
Latest News

Laser processing is a matter for the head – LZH at the Hannover Messe 2019

25.03.2019 | Trade Fair News

A Varied Menu

25.03.2019 | Life Sciences

‘Time Machine’ heralds new era

25.03.2019 | Information Technology

VideoLinks
Science & Research
Overview of more VideoLinks >>>