Category Archives: Aquatic Life

Analysis of Kepone Levels in James River Fish in 2016 Issued by VIMS Scientists in June 2017

In June 2017, scientists at the Virginia Institute of Marine Science (VIMS) issued their latest report on kepone levels in fish in the James River.  The VIMS researchers found that 35 percent of tissue samples from Striped Bass and White Perch taken in 2016 contained no detectable kepone, while 65 percent still contain detectable levels of the chemical.  Kepone in the James is a legacy of illegal discharges by the former Allied Chemical operation at Hopewell, which resulted in a $13.2 million settlement in 1977.

VIMS researchers sampled James River fish for kepone levels annually from 1975 to 2000, then again in 2002, 2004, 2009, and 2016.  Regarding the results from 2016, report co-author James Unger stated, “Kepone in fish tissues has continued to decline exponentially since 1980 and should be near or below the detection limit in all samples by 2020 or 2025 if current trends continue.”

Source: VIMS report offers mixed news on James River Kepone, William & Mary  News, 6/12/17.

Some Fish School, But Humans Interested in Aquaculture Can GO to “Fish School” at Virginia State University, July 5-7, 2017

On July 5-7, 2017, in Petersburg, Virginia Cooperative Extension at Virginia State University holds its annual  Fish School.  The event, emphasizing using aquatic resources to provide local food, offers educational sessions on growing fish or shellfish for a hobby or as a commercial enterprise.  Participants may register for single days or for the whole event.

Topics in 2017 include the following:
Day 1 – Species and Marketing, Aquaculture Nutrition, Water Quality and Fish Health; Day 2 – Farm Pond Management, Freshwater Shrimp, Cage Culture;
Day 3 – Greenhouse Production Systems/Aquaponics, Sampling fish populations, Over-Wintering Solar Power Energy Unit, Recirculating Aquaculture Systems.

Each day will have hands-on activities.

For more information, visit https://www.ext.vsu.edu/events/2017/7/5/fish-school; or contact Brian Nerrie, VSU aquaculture extension specialist, at (804) 524-5903 or bnerrie@vsu.edu.

On Virginia Water Radio for 6-5-17: Herp Blitz, by the Virginia Herpetological Society

Virginia Water Radio’s episode for the week of June 5, 2017, is “Amphibians and Reptiles are the Stars of Herp Blitz.”  The 3 min./56 sec. episode, available online at http://www.virginiawaterradio.org/2017/06/episode-371-6-5-17-amphibians-and.html, focuses on the “herp”-finding work of the Virginia Herpetological Society, including the 2017 “Herp Blitz,” June 10-11 in Hidden Valley Wildlife Management Area in Washington County  (the Society’s information on the 2017 Herp Blitz is online at http://www.virginiaherpetologicalsociety.com/news/index.html#).

Logo of the Virginia Herpetological Society, accessed at the Society’s Web site, http://www.virginiaherpetologicalsociety.com/index.html.

Virginia Water Radio’s is a weekly broadcast/podcast produced by the Virginia Water Resources Research Center.  The home page is http://www.virginiawaterradio.org.  Have a listen or two!

Chesapeake Bay Report Card from University of Maryland for 2016 Released May 8, 2017

On May 8, 2017, the University of Maryland’s Center for Environmental Science released its annual “Chesapeake Bay Report Card” on the status of biology and water quality in the Chesapeake Bay, showing that conditions in 2016 were better than they had been in most years since 1986.  This year’s report had an overall “grade” of 54%, rated a C (“moderately healthy”), compared to 53% for 2015 data, 50% for 2014 data, and 45% for 2013 data.

The Center analyzes data on five chemical or physical indicators and five biological indicators, assessing how close (on a percentage basis) the indicators are to reaching a set of established goals, in response to pollution-reducing and habitat-improving actions.  The indicators are as follows: dissolved oxygen, nitrogen, phosphorus, chlorophyll, water clarity, aquatic “grasses” (submerged aquatic plants), benthic (bottom-dwelling) community, Blue Crabs, Bay anchovy, and Striped Bass.  Only the first seven are included in the Overall Health Index; the data on Blue Crabs, Bay anchovy, and Striped Bass are not part of the overall score.  From 2015 to 2016, scores improved or remained steady for all but two of the indicators, nitrogen and the benthic community.

An image showing the grades and trends for 15 Bay regions is shown below.

Bay report card

Graph of the report card scores and trends in data from 2016 in 15 Chesapeake Bay regions.  Image from Chesapeake Bay Report Card Shows Steady Recovery, University of Maryland Center for Environmental Science News Release, 5/8/17.

Sources:
University of Maryland Center for Environmental Science, “Chesapeake Bay Report Card,” online at http://ecoreportcard.org/report-cards/chesapeake-bay/ (as of 5/31/17).

Chesapeake Bay Report Card Shows Steady Recovery, University of Maryland Center for Environmental Science News Release, 5/8/17, online at http://www.umces.edu/news/chesapeake-bay-report-card-shows-steady-recovery (as of 5/31/17).

For Virginia Water Central News Grouper posts previous University of Maryland Bay report cards and on other reports of Chesapeake Bay conditions, please see this link: https://vawatercentralnewsgrouper.wordpress.com/?s=Bay+Report+Card.

For an audio take on another Bay “report card”—the Chesapeake Bay Program’s “Bay Barometer”—have a listen to Virginia Water Radio Episode 305 (2-29-16) (3 min./49 sec.).

Chesapeake Bay Submerged Aquatic Vegetation Increased Eight Percent in 2016, According to Bay Program and VIMS Annual Survey Results Released in April 2017

In late April 2017, the Chesapeake Bay Program and the Virginia Institute of Marine Science (VIMS) reported that the acreage of submerged aquatic vegetation (SAVs) in the Bay (also called “underwater grasses” or “Bay grasses”) reached 97,433 acres in 2016, an increase of eight percent from 2015.  This continued a string of annual increases since 2012; for example, the increase from 2014 to 2015 was 21 percent.

The 2016 Baywide coverage of SAVs was the largest in the history of the annual aerial survey, which began in 1984.

According to the Bay Program’s news release, “Experts attribute the rise in underwater grass abundance to a strong increase in the tidal freshwater and moderately salty regions of the Bay, with Widgeon Grass in particular expanding in the latter region.  However, because widgeon grass is a “boom and bust” species—its abundance can rise and fall from year to year—a widgeon-dominant spike is not guaranteed to persist in future seasons.”

SAV chart

Chart of Chesapeake Bay submerged aquatic vegetation (SAVs) from 1984 to 2016, based on the annual aerial survey by the Virginia Institute of Marine Science.  Graph from More than 97,000 acres of underwater grasses recorded in Chesapeake Bay, Chesapeake Bay Program News, 4/27/17.

Sources:
More than 97,000 acres of underwater grasses recorded in Chesapeake Bay, Chesapeake Bay Program News, 4/27/17.
Survey: another good year for Bay’s underwater grasses, Virginia Institute of Marine Science, 4/26/17.

Some news accounts on the 2017 survey:
Underwater grasses up 8%; acreage is highest in decades, Bay Journal, 4/27/17.
VIMS: Chesapeake Bay sees another record year in underwater grass abundance, Daily Press, 4/27/17.

For more information on Chesapeake Bay submerged aquatic vegetation:
Chesapeake Bay Program/Chesapeake STAT, “Submerged Aquatic Vegetation (SAV),” online at http://www.chesapeakeprogress.com/abundant-life/vital-habitats/sav (as of 5/25/17).

Virginia Institute of Marine Science (VIMS), “SAV in Chesapeake Bay and Coastal Bays,” online at http://web.vims.edu/bio/sav/index.html (as of 5/25/17).

VIMS, “SAV Coverage in Chesapeake Bay 2016,” online at https://infogr.am/copy_sav_area_by_salinity_zone (as of 5/25/17).  This site has interactive charts on Bay SAV by salinity zone in 2016.

Chesapeake Bay Blue Crab Survey for Winter 2017 Shows 31-percent Increase in Spawning Females over 2016, But Declines in Juveniles and Total Population

On April 19, 2017, the Virginia Marine Resources Commission (VMRC), the Maryland Department of Natural Resources (Md. DNR), and the Virginia Institute of Marine Science (VIMS) reported the results of the latest winter dredge survey of Blue Crab populations in the Chesapeake Bay.  Since 1990, the survey has been conducted each year from December to March by VIMS and the Md. DNR.  The report for the 2016-17 survey showed increases over the previous year in spawning females but decreases in the number of juveniles and in the total population.  Despite the decreases, the population was the 11th highest recorded.   Survey results since 2008 are available online at http://www.vims.edu/research/units/programs/bc_winter_dredge/results/index3.php.

Following is an excerpt from the VMRC’s April 19, 2017, news release on the 2016-17 survey (see Sources, below, for the Internet link to the news release PDF):

“The Virginia Marine Resources Commission today released the results of the 2017 blue crab winter dredge survey, which shows a 31-percent increase in adult female crabs and forecasts another year of improved harvests.

“This is the highest level of adult, spawning age females recorded in the 28-year history of the Bay-wide crab winter dredge survey. …The results of the 2017 winter dredge survey show the total population of blue crabs in the Chesapeake Bay fell a bit, by 18 percent, due to a decline in the number of juvenile crabs, but remains at the 11th highest level ever recorded by the winter dredge survey.   This year’s female spawning stock increased by 31 percent, from 194 million to 254 million crabs, which surpassed the scientifically recommended target of 215 million spawning female crabs and remains well above the minimum safe threshold of 70 million crabs.  Spawning age female crabs are the cornerstone to maintaining a vibrant crab stock, and depend on conservative and cooperative fishery management efforts among the Bay jurisdictions.

“The adult male crab stock fell by 16 percent, from 91 million to a still-substantial 76 million.  However, the juvenile abundance plummeted by 54 percent, from 271 million to 125 million, which is the fourth lowest level on record.

“This was unfortunate but not unprecedented. Optimal spawning conditions do not occur every year.  Successful crab reproduction naturally fluctuates and can be affected by wind, currents, storms, temperature, and cannibalism. In recent years, post-reproduction predation events and environmental factors have caused at times dramatic downturns in crab stock abundance. For example, the level of juveniles fell from 581 million in 2012 to a mere 111 million in 2013.

“This reproductive variability highlights the need for fishery managers to continue to enhance resilience of the stock through adaptive management to compensate for unusual or extreme environmental conditions and the resulting impacts on reproductive success….

“A Bay-wide 10-percent crab harvest reduction was enacted in 2014 by VMRC, Maryland, and the Potomac River Fisheries Commission to combat low overall crab abundance and to boost a dangerously depleted female spawning stock.   Bay fishery managers have since refined their management regimen to focus on conserving juvenile crabs as well as spawning age female crabs. Each year’s juveniles become the next year’s spawning stock.  Adjusting catch regulations to conserve more of today’s juveniles from harvest when they reach market size in the fall and emerge in the spring after overwintering in the water bottom increases the likelihood they will survive to spawn another generation of abundant crabs in the summer. …

“The Bay-wide commercial harvest increased by 20 percent last year, from 50 million pounds to 60 million pounds, and remains at sustainable levels.  Since 2014, the Bay-wide commercial crab harvest has jumped 71 percent while overall crab abundance has increased by 53 percent.  The current low level of juvenile crabs appears to preclude the reopening of the winter crab dredge fishery, which has remained closed since 2008.

“The annual Bay-wide Winter Dredge Survey is the primary assessment of the Bay’s blue crab population, and has been conducted annually by the Virginia Institute of Marine Science and Maryland’s Department of Natural Resources since 1990.  The survey employs crab dredges to sample blue crabs at 1,500 sites throughout the Chesapeake Bay from December through March.  Sampling during winter when blue crabs are usually buried in the mud and stationary, allows scientists to develop, with good precision, estimates of the number of crabs present in the Bay.  The Chesapeake Bay Stock Assessment Committee (CBSAC), a subcommittee of the Sustainable Fisheries Goal Implementation Team,is reviewing the new survey results and will release their full analysis of the results in the 2017 Blue Crab Advisory Report this summer.  The annual advisory report is used by managers as they review and update fishery regulations. …”

Following are the lowest and highest estimates of key parts of the Bay crab population since 1990:
Total (both sexes and all ages) – low of 251 million in 2007; high of 852 million in 1993.
Spawning-age females – low of 53 million in 1999; high of 254 million in 2017.
Juvenile-age (both sexes): low of 105 million in 1992; high of 581 million in 2012.

A table of all the results since 1990 is available in the VMRC’s April 19, 2016, news release.

Sources:
Scientific Survey Shows Promising Blue Crab Stock Abundance with Boost to Adult Females (PDF), Virginia Marine Resources Commission News Release, 4/19/17.
Scientific survey shows highest-ever level of spawning-age female crabs, Virginia Institute of Marine Science News Release, 4/19/17.

Some news accounts on the winter 2016-17 survey are the following:
Survey finds Bay crab population strong, with record number of females, Bay Journal, 4/19/17.
The Chesapeake Bay was less crabby last winter, survey says, Virginian-Pilot, 4/19/17.

For previous News Grouper items on the Blue Crab winter dredge survey, please see this link: https://vawatercentralnewsgrouper.wordpress.com/?s=blue+crab+winter+dredge+survey.

On Virginia Water Radio for 5-8-17: Mayflies Get the Call from Patrick County High School Students

Virginia Water Radio’s latest episode, for the week of May 8, 2017, is “A High School Call for Mayflies.”  The 4 min./14 sec. episode, available online at http://www.virginiawaterradio.org/2017/05/episode-367-5-8-17-high-school-call-for.html focuses on a diverse and unusual group of aquatic insects.  The episode features guest voices of students from Patrick County High School in Stuart, Va.

367 Photo Mayfly adult Lee County VA May 2010 by Tony Timpano RCVD 5-1-17

Adult mayfly photographed in Lee County, Va., May 2010.  Photo by Tony Timpano, used with permission.

Virginia Water Radio’s is a weekly broadcast/podcast produced by the Virginia Water Resources Research Center.  The home page is http://www.virginiawaterradio.org.  Have a listen or two!