The secret life of Ireland's smooth-hound sharks

4 years of research reveals unique opportunity to conserve shark species

2010-10-04

(Press-News.org) They grow to over a meter in length, can weigh up to twelve kilos and each summer they swarm into the shallow waters of the Irish east coast. Despite this, the starry smooth-hound has remained Ireland's least well known shark species. However, thanks to researchers at University College Dublin, whose work is now published in the Journal of Fish Biology, this may be about to change.

Dr. Edward Farrell, who recently graduated from UCD School of Biology & Environmental Science, spent the last four years studying these unusual sharks. Under the supervision of Dr. Stefano Mariani of the SBES and Dr. Maurice Clarke of the Marine Institute, the PhD project successfully investigated the age, growth, reproduction and identification of the species in the Northeast Atlantic.

"It's amazing how little was known about this species considering their size and abundance on the east coast," said Farrell. "Until recently we weren't even sure what species we were dealing with but we developed a genetic method which allowed us to confirm that it is the starry smooth-hound which occurs in Irish waters and not the related common smooth-hound. Once this was established we were able to investigate their life-history."

Starry smooth-hounds were previously considered to be a fast growing and early maturing species, meaning they were not a conservation concern. However the results of the four year project have revealed that starry smooth-hounds in Irish waters actually grow twice as slowly as previously estimated and only reproduce every two years rather than annually as is the case in the Mediterranean.

"Some of the findings are quite worrying for the species as males don't mature until they are 4-5 years old and females until they are 6 years old, said Farrell. "Females also appear to take two years to complete the reproductive cycle. The pups develop inside the female for approximately 12 months before being born after which the female has a resting period of about another year before she is capable of becoming pregnant again."

With such a slow reproductive rate, unregulated commercial fishing could have a serious impact on the species in a short time, as was seen with the spurdog fisheries in the 1980s. Spurdogs were once the most abundant shark species in the Northeast Atlantic however they have been all but wiped out by commercial fisheries and are now listed as critically endangered on the IUCN Redlist.

Starry smooth-hounds are not a valuable commercial species in Ireland but on the continent they are highly sought after and the landings from French boats, currently about 2640 tonnes annually, are increasing. The previous lack of knowledge of their basic life history in the Northeast Atlantic has prevented the development of management and conservation strategies.

Once abundant in the Mediterranean Sea and Southern European waters, years of over fishing have caused their disappearance from much of their former range. In Irish waters though, starry smooth-hounds seem to be increasing in abundance. The reasons for this are unclear but it does offer the unique opportunity to help conserve this enigmatic species.

These findings of the project indicate that starry smooth-hounds are more susceptible to exploitation than previously thought and management measures are needed now to ensure their conservation.

"There are currently no management measures for this species in European waters mainly due to the lack of biological information," says Farrell. "So our main aim was to gather the necessary data. Hopefully this can be used now to ensure their sustainability and prevent a repeat of the overexploitation seen in Mediterranean waters."

Stefano Mariani believes that it is paramount to protect these sharks in Irish waters. "Smooth-hounds have a very specialized diet: they don't eat fish, they feed on bottom-dwelling shellfish, crunching crabs with their very peculiar molariform teeth. These animals are likely to have a very important role in the trophic web".

Starry smooth-hound sharks are also highly sought-after and respected by anglers, and they certainly provide an additional excitement to our coasts.

"Dublin Bay offers tourists the opportunity to easily observe two species of seals," concluded Mariani. "We should be proud that our coasts also provide beach-goers with a chance of swimming alongside beautiful and harmless sharks. There are not many other places like this in Europe."

INFORMATION:

For more information and news on the sharks, skates and rays in Irish waters check out the new Irish Elasmobranch Group website: http://www.irishelasmobranchgroup.org

[Attachments] See images for this press release:

ELSE PRESS RELEASES FROM THIS DATE:

New study highlights sexual behavior, condom use by US individuals ages 14 to 94

2010-10-04

BLOOMINGTON, Ind. -- Findings from the largest nationally representative study of sexual and sexual-health behaviors ever fielded, conducted by Indiana University sexual health researchers, provides an updated and much needed snapshot of contemporary Americans' sexual behaviors, including a description of more than 40 combinations of sexual acts that people perform during sexual events, patterns of condom use by adolescents and adults, and the percentage of Americans participating in same-sex encounters. The National Survey of Sexual Health and Behavior (NSSHB) was conducted ...

Study finds foreclosure crisis had significant racial dimensions

2010-10-04

Princeton, NJ – September 30, 2010 – Although the rise in subprime lending and the ensuing wave of foreclosures was partly a result of market forces that have been well-documented, the foreclosure crisis was also a highly racialized process, according to a study by two Woodrow Wilson School scholars published in the October 2010 issue of the American Sociological Review. Woodrow Wilson School Ph.D. candidate Jacob Rugh and Woodrow Wilson School's Henry G. Bryant Professor of Sociology and Public Affairs, Douglas Massey, assessed segregation and the American foreclosure ...

Food allergies raise risk of asthma attacks

2010-10-04

Food allergies are more common among people with asthma and may contribute to asthma attacks, according to one of the most comprehensive surveys of food allergies ever undertaken. National Jewish Health Associate Professor of Pediatrics Andrew H. Liu and his colleagues also report in the November 2010 Journal of Allergy and Clinical Immunology that food allergies are more prevalent among children, males and non-Hispanic blacks. "Our study suggests that food allergies may be an important factor, and even an under-recognized trigger for severe asthma exacerbations," said ...

Study focuses on mephedrone use in Northern Ireland post-ban

2010-10-04

Researchers at Queen's University Belfast have completed one of the first studies of mephedrone use in Northern Ireland since the drug was outlawed earlier this year. They found that the ban did not deter those mephedrone users surveyed from taking the substance. Interviews with 23 mephedrone users were completed during a two-month period (May and June 2010) following the legislation that made the drug illegal in the UK. Study participants were aged 19 to 51 years, around half of whom (12) were female. 19 of the 23 people who took part in the study were employed, and ...

Children, males and blacks are at increased risk for food allergies

2010-10-04

A new study estimates that 2.5 percent of the United States population, or about 7.6 million Americans, have food allergies. Food allergy rates were found to be higher for children, non-Hispanic blacks, and males, according to the researchers. The odds of male black children having food allergies were 4.4 times higher than others in the general population. The research, which was funded by the National Institutes of Health and appears in the Journal of Allergy and Clinical Immunology, is the first to use a nationally representative sample, as well as specific immunoglobulin ...

Walnuts, walnut oil, improve reaction to stress

2010-10-04

A diet rich in walnuts and walnut oil may prepare the body to deal better with stress, according to a team of Penn State researchers who looked at how these foods, which contain polyunsaturated fats, influence blood pressure at rest and under stress. Previous studies have shown that omega-3 fatty acids -- like the alpha linolenic acid found in walnuts and flax seeds -- can reduce low density lipoproteins (LDL) -- bad cholesterol. These foods may also reduce c-reactive protein and other markers of inflammation. "People who show an exaggerated biological response to stress ...

What mimicking one's language style may mean about the relationship

2010-10-04

People match each other's language styles more during happier periods of their relationship than at other times, according to new research from psychologists at The University of Texas at Austin. "When two people start a conversation, they usually begin talking alike within a matter of seconds," says James Pennebaker, psychology professor and co-author of the study. "This also happens when people read a book or watch a movie. As soon as the credits roll, they find themselves talking like the author or the central characters." This tendency is called language style matching ...

Lack of private health insurance impacted cancer survival

2010-10-03

MIAMI — Lack of private health insurance and its consequent lack of access to care appears to affect mortality among patients with uterine cancer and may partly explain the mortality disparity between African-Americans and other racial groups, according to data presented at the Third AACR Conference on The Science of Cancer Health Disparities. "African-Americans were twice as likely to die within four years compared to white patients after adjusting for age, facility and education level. However, when insurance, treatment and clinical factors were accounted for, this ...

Social support post-cancer lacking among minority women

2010-10-03

MIAMI — Nonwhite women reported receiving less social support than white women after cancer treatment, according to data presented at the Third AACR Conference on The Science of Cancer Health Disparities, held Sept. 30-Oct. 3, 2010. "This is an important finding when designing and promoting social support resources for female cancer survivors to better include cancer survivors of color," said study author Jennifer M. Jabson, M.P.H., Ph.D., a postdoctoral research fellow in the department of community health sciences at Boston University. "This might be useful when interventionists ...

Decreased survival for Puerto Rican women with 'triple-negative' breast cancer subtype

2010-10-03

MIAMI — Puerto Rican women who had breast cancer that lacked estrogen and progesterone receptors and did not overexpress the HER2neu protein (triple-negative) had worse survival than those with other types of invasive breast cancer, according to a study presented at the Third AACR Conference on The Science of Cancer Health Disparities, held Sept. 30 – Oct. 3, 2010. "As the incidence of breast cancer rises in Puerto Rico, following U.S. trends, it is important to understand the association of disease subtypes with survival," said Ana P. Ortiz Martinez, M.P.H., Ph.D., associate ...

The secret life of Ireland's smooth-hound sharks

ELSE PRESS RELEASES FROM THIS DATE:

LAST 30 PRESS RELEASES: