the past, present, and future conservation status of the chesapeake bay blue crab
DESCRIPTION
Presentation for Biology 405W; Kate Stoutenburgh, Old Dominion University, 2013TRANSCRIPT
A REVIEW OF THE PAST, PRESENT, AND FUTURE CONSERVATION STATUS OF THE CHESAPEAKE BAY BLUE CRAB
By: Kate Stoutenburgh
Faculty Sponsor: Dr. Kent Carpenter
Talk Outline
Blue Crab Background Importance Threats Current Conservation Efforts Need for More Conservation Action Discussion and Questions
Background
Callinectes sapidus
Habitat Range Major Commercial
Fishery Stock suffered a
collapse in 1990s http://commons.wikimedia.org/wiki/File:The_Childrens_Museum_of_Indianapolis_-_Atlantic_blue_crab.jpg
Economical Importance
Single most commercially exploited species in Chesapeake Bay
In 2011, the commercial landing of blue crab in the Chesapeake Bay was 39,453 metric tons worth $82,509,522 (NOAA, 2011)
Many Chesapeake Bay watermen rely heavily on the blue crab for income
Ecological Importance
Keystone predator Important prey of striped bass and other
commercial species Trophic link between benthic and pelagic
systems
Life History
http://classic.sidwell.edu/us/science/21bio/new/Crab_Poster_2005/Crab_Life_Cycle_files/image002.jpg
The Crash
This graph shows the collapse of the blue crab fishery in the 1990s, followed by an increase in abundance after stricter fishing limits were put into effect in the early 2000s (Miller et al., 2011)
Current Status
Recovering slowly from stock crash in 1990s
Stock is currently above target abundance
Abundance in 2012 lower than 2010 and 2011
Juvenile recruitment estimate highest ever recorded
Still threatened by human actions
Fishing Exploitation
What is juvenile recruitment? Blue crab population in the bay is
recruitment limited Recruitment is highly variable Stock is being fished at Maximum
Sustainable Yield (MSY) Fishing at MSY leaves stock vulnerable
when variations in recruitment occur
Current Overfishing Guidelines
This graph shows the current guidelines used to define overfishing of the crab stock in Chesapeake Bay (Miller et al. 2011)
Climate Change and Habitat Loss
Climate change may both help and hurt blue crabs Rising temperatures decrease
overwintering mortality Rising sea levels destroy coastal marsh
habitat Marsh habitat also lost due to human
activity and coastal development
Reduction in Fishing Effort
The most recent stock assessment of the blue crab in the Chesapeake Bay has recommended a reduction in fishing exploitation
It has also been recommended that females be used as a measure of population abundance
New Overfishing Guidelines
This graph shows the new overfishing definition recommendations of the most recent blue crab stock assessment (Miller et al., 2011)
Marine Protected Area and Corridor
What is an MPAC? VSSC established in lower bay in 2000 to
protect migrating females Increasing area of MPAC could help
protect even more females on their way to mate and spawn
Highly effective and low cost to implement
Hatcheries
Involves releasing hatchery raised juveniles into the wild
Has great success, but is costly From 2002-2006, over 290,000 hatchery
raised blue crabs were released into the wild.
The addition of these individuals into the wild increased local populations around areas of release by 50-250% (Zohar et al. 2008)
Why More Needs to be Done High variability in juvenile recruitment
can cause another stock crash Fishing at MSY can devastate a
population if recruitment drops suddenly Climate change is an unpredictable
factor
Discussion
Blue crabs are important economically and ecologically in the Chesapeake Bay
The population has crashed in the past and is currently vulnerable to threats from climate change and human exploitation
More extensive conservation efforts are needed to ensure a healthy population in the face of these threats
Thank You!
Questions?