Navigation Links
Whale sharks may produce many litters from 1 mating, paternity test shows
Date:8/24/2010

How do female whale sharks meet their perfect mates and go on to produce offspring? While little is known about the reproductive behavior of these ocean-roaming giants, a newly published analysis led by University of Illinois at Chicago biologist Jennifer Schmidt reveals new details about the mating habits of this elusive, difficult-to-study fish.

Schmidt, a UIC associate professor of biological sciences, determined paternity of 29 frozen embryos saved from a female whale shark caught off the coast of Taiwan in 1995. The embryos, studied in collaboration with Professor Shoou-Jeng Joung at the National Taiwan Ocean University, are extremely rare.

The pregnant shark carried a surprisingly large number of embryos -- 304 -- still in the uterus and representing a spectrum of age and development stages ranging from being still egg-encased to developed, near-term animals.

Schmidt and her colleagues spent several years developing DNA genetic markers to study whale sharks, initially for population genetics, but in this study the tool was used to determine paternity.

Shark reproduction is still an emerging science, but what is known suggests that most broods are sired by more than one male. That is not what Schmidt found with this particular female whale shark.

"These differently aged embryos -- itself unusual across animal species -- had the same father," Schmidt said. "We have to be very cautious in drawing conclusions from a single litter, but the data suggest female whale sharks store sperm after a single mating event, and subsequently fertilize their own eggs as they are produced."

If the finding can be supported from analysis of other whale shark litters, Schmidt said, "it would suggest that there is no whale shark breeding ground where large numbers of animals meet to mate, but rather that mating occurs as an isolated event."

Follow-up studies may be serendipity. International protocols protect whale sharks from capture, few are housed in aquariums, and those that are are usually less than 25 years old and not yet sexually mature. Scientists typically study whale sharks at seasonal feeding grounds, but those animals are usually juveniles not mature enough to breed. Rarely are adult females observed in the wild.

"Protections for whale sharks have increased in many parts of the world, yet shark numbers seem to be declining, and the average size is getting smaller," said Mark Meekan, principal research scientist with the Australian Institute of Marine Sciences.

"This is a classic sign of overfishing, where larger, more valuable animals are selectively removed," he said. "Targeted fishing of breeding-age animals in a late-maturing species can be devastating for its survival."


'/>"/>

Contact: Paul Francuch
francuch@uic.edu
312-996-3457
University of Illinois at Chicago
Source:Eurekalert

Related biology news :

1. Blue whales align the pitch of their songs with extreme accuracy, study finds
2. Lone whales shout to overcome noise
3. UCLA biologists report how whales have changed over 35 million years
4. DNA analysis suggests whale meat from sushi restaurants in L.A., Seoul originated from Japan
5. Experts gather to solve mystery of largest recorded die-off of great whales
6. MMS and NOAA scientists study prey of Gulf of Mexico sperm whales
7. New study finds link between marine algae and whale diversity over time
8. New study suggests minke whales are not preventing recovery of larger whales
9. Zoning the ocean may help endangered whales to recover
10. Story of 4.5 million-year-old whale unveiled in Huelva
11. The pitch of blue whale songs is declining around the world, scientists discover
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:3/21/2016)... -- Unique technology combines v ...   Xura, Inc. (NASDAQ: ... communications services, today announced it is working alongside SpeechPro ... particularly those in the Financial Services Sector, the ability ... a mobile app, alongside, and in combination with, traditional ...
(Date:3/15/2016)... , March 15, 2016 Yissum ... , the technology-transfer company of the Hebrew University, announced ... of remote sensing technology of various human biological indicators. ... raising $2.0 million from private investors. ... based on the detection of electromagnetic emissions from sweat ...
(Date:3/11/2016)... March 11, 2016 --> ... research report "Image Recognition Market by Technology (Pattern Recognition), ... Advertising), by Deployment Type (On-Premises and Cloud), by Industry ... published by MarketsandMarkets, the global market is expected to ... 29.98 Billion by 2020, at a CAGR of 19.1%. ...
Breaking Biology News(10 mins):
(Date:5/3/2016)... ... May 03, 2016 , ... In a list published by the Boston ... 76 fastest-growing private companies; a small percentage of the state's 615,000+ small businesses. The ... percent change in revenue from 2012 to 2015. , As this award ...
(Date:5/3/2016)... - And Other Rising Companies - a ... Biologics  - Biosimilar Drug Producers - Your ... Who are the most important and promising ... potentials? Discover, in our updated survey, organisations, outlooks from ... forecasting. Visiongain,s new study analyses ...
(Date:5/2/2016)... ... May 02, 2016 , ... Meister Media Worldwide ... fresh look and added functionality give the agricultural world a taste of Meister ... shift in agriculture – from precision farming via satellites and Unmanned Aerial Vehicles ...
(Date:4/29/2016)... ... 2016 , ... Amendia, Inc., a leading designer, developer, manufacturer ... completion of a significant transaction and partnership that positions Amendia for accelerated growth ... Kohlberg & Company, L.L.C. (“Kohlberg”), a leading private equity firm specializing in middle ...
Breaking Biology Technology: