Navigation Links
Study looks at gray seal impact on beach water quality
Date:12/20/2012

Scientists from the newly created Northwest Atlantic Seal Research Consortium (NASRC) are using data collected by the Massachusetts Department of Public Health (MDPH) to investigate whether seals may impact beach water quality along Outer Cape Cod.

A growing population of gray seals has been cited as the reason for beach closures due to poor water quality on the outer Cape. But is there evidence to support these water quality statements?

"We took some basic steps to assess whether there is cause for concern," said Rebecca J. Gast, an associate scientist at the Woods Hole Oceanographic Institution (WHOI) and member of the NASRC. "As far as I know, no one has looked at the data to ask these questions before."

The precise number of gray seals in the area is not known; however, over the last 30 years, in areas where there were once a few hundred, there are now several thousand.

There are three sites or "haul-outs" on the lower Cape where large numbers of gray seals leave the water to avoid predators, regulate their body temperature, and socialize. Sites in the area that host several hundred seals at low tide include High Head on the outer Cape in the National Seashore/Truro area; Jeremy Point on the Cape Cod Bay side of Wellfleet; and North Island in Chatham (see list of beaches).

To conduct their analysis, the researchers examined water quality data from 89 sites at public beaches in six surrounding towns including Provincetown, Truro, Wellfleet, Eastham, Orleans, and Chatham. The water samples, which were collected and analyzed by the MDPH between 2003 and 2012, measure levels of the Fecal Indicator Bacteria (FIB) enterococci, a group of bacterial species which are typically found in human and animal intestines and feces. Although most enterococci do not typically cause illness in humans, it is used to indicate the possible presence of other disease-causing organisms associated with fecal contamination.

In marine waters, the accepted level of enterococci for a single water sample is 104 colony forming units per 100 milliliters (cfu/100 ml) of bathing water or below. Any sample with a count greater than 104 cfu/100 ml is called an "exceedance," and signs are posted at the beach to warn the public against recreational use of the water.

"Our first task was to examine the total number of exceedance events each year for the lower Cape region," says Gast, "so we could determine whether there was a trend towards increased closures which would suggest a decline in water quality."

"Bathing beach water quality is highly variable from year to year, and our analysis of 10 years of data shows there was no change in the trend of water quality exceedances for the region," continues Gast. "That being said, there are differences in water quality trends when you look at the individual towns."

Armed with this overview of the state of water quality in the six towns, the researchers went on to examine whether the beaches closest to large seal haul-outs had more closures due to FIB than other beaches.

"We divided the beaches in the lower Cape region into those within 5 miles of seal haul-outs, and those more than 5 miles from seal haul-outs. This distance was chosen to represent what we thought would be a reasonable distance for the dispersion and inactivation of FIB on a daily tidal schedule," Gast explains.

The analysis found the beaches near the haul-outs actually showed a decreasing trend in yearly FIB exceedance events over the last decade, while the beaches away from seal haul-outs showed an increasing trend in beach postings due to FIB.

"The evidence indicates that at this time, the water quality at beaches near large seal haul-outs is not worse than at beaches without large numbers of seals nearby," concludes Gast. "In fact, 4 of the 5 beaches in Chatham Harbor that are close to the seal haul-outs have never had an FIB exceedance event."

Members of the NASRC will continue to assess and monitor the effects of seal populations on the ecology and economy of the region. Research that would be useful includes continued monitoring of water quality at/near haul-out beaches, models of predominant water current directions and speeds in the area to better assess bacterial dispersion and transport, and development of quantitative fecal source tracking methods for seals. The researchers are looking for funds to do this work.


'/>"/>

Contact: WHOI Media Relations
media@whoi.edu
508-289-3340
Woods Hole Oceanographic Institution
Source:Eurekalert

Related biology news :

1. Study reveals that animals contribute to seagrass dispersal
2. UC Irvine study of leaping toads reveals muscle-protecting mechanism
3. NTU study finds ways to prevent muscle loss, obesity and diabetes
4. Hass Avocado Board study published in Food & Function journal
5. Univ. of MD School of Medicine to study drug-resistant malaria in Myanmar
6. Study offers insights into role of muscle weakness in Down syndrome
7. University of Tennessee study predicts extreme climate in Eastern US
8. New menhaden study will help identify balance between fishing and preserving Bay forage fish
9. Study uncovers mechanism used by BRCA1 to suppress tumors
10. Penn Study shows resistance to cocaine addiction may be passed down from father to son
11. Study confirms prognostic value of new IASLC/ATS/ERS adenocarcinoma sub-classification
Post Your Comments:
*Name:
*Comment:
*Email:
(Date:4/26/2016)... , April 27, 2016 ... the  "Global Multi-modal Biometrics Market 2016-2020"  report to ... ) , The analysts forecast the ... CAGR of 15.49% during the period 2016-2020.  ... number of sectors such as the healthcare, BFSI, ...
(Date:4/15/2016)... April 15, 2016  A new partnership announced ... accurate underwriting decisions in a fraction of the ... priced and high-value life insurance policies to consumers ... With Force Diagnostics, rapid testing (A1C, Cotinine ... readings (blood pressure, weight, pulse, BMI, and activity ...
(Date:4/14/2016)... 2016 BioCatch ™, the ... announced the appointment of Eyal Goldwerger as ... Goldwerger,s leadership appointment comes at a time of ... deployment of its platform at several of the world,s ... discerns unique cognitive and physiological factors, is a winner ...
Breaking Biology News(10 mins):
(Date:5/25/2016)... (PRWEB) , ... May 25, 2016 , ... Scientists at ... line options being tried for mesothelioma may be hampering the research that could lead ... research. Click here to read it now. , The team evaluated 98 ...
(Date:5/24/2016)... ... 2016 , ... Cell therapies for a range of serious ... at Worcester Polytechnic Institute (WPI) that yielded a newly patented method of converting ... novel method, developed by WPI faculty members Raymond Page, PhD, professor of practice ...
(Date:5/23/2016)... (PRWEB) , ... May 23, 2016 , ... The need for blood donations in South ... week by the South Texas Blood & Tissue Center, blood donations are on the decline. ... years, and they are down 21 percent in South Texas in the last four years ...
(Date:5/23/2016)... May 23, 2016 - Leading CRO,s Use ... - Frontage Implement a Single Platform to Manage End-to-end Operations ... Within the Bioanalytical lab Frontage Laboratories, a full-service contract ... and China , has selected IDBS, ... In addition to serving as the global electronic lab notebook (ELN), ...
Breaking Biology Technology: