Goliath Grouper. Photo by W. Stearns is licensed under Ocean Research and Conservation Association |
Fisheries managers have studied the
ecological influences on Goliath grouper for a long time now, and have found
that these grouper have a large dependence on mangroves. Goliath grouper depend
on mangroves largely for spawning and nursery grounds, as well as recruitment
areas for adulthood. Mangroves provide a habitat for the juvenile groupers to
obtain nutrients and protection before they reach adulthood and head out to coral
reefs or sunken ships nearby (Frias-Torres 2006; Koenig et al. 2007). Koenig
(2014) states “in the 1900s, before the harvest ban, poor water management in
South Florida initiated the [population] decline by reducing the quality and
coverage of mangrove habitat.” Without stable sanctuary for the juveniles, they
were not likely to survive and grow. On top of that, immense amount of fishing
pressure on the grouper enhanced the steady population decline before the
harvest ban. Now with the lack of heavy fishing pressure, the species has
recovered significantly (Koenig 2014) by finding safeguard in the few quality
areas of mangrove habitat such as the Ten Thousand Islands and the Everglades
off of the Florida coast. However, much of the mangrove that is available is
largely threatened or declining due to industrial and agricultural development
and pollutions. Therefore, if the mangrove habitat is not effectively managed
and conserved, lifting the harvest ban will likely have negative repercussions
and promote a decline in Goliath grouper population.
It’s critical to recognize that the
current abundance and stability of mangroves could result in a large decline of
Goliath grouper if the harvest ban is lifted. The low abundance of mangroves is
a direct result of the channelization to redirect freshwater flow from the
Everglades to industrial areas, mosquito control in the tropical regions, and
of course the industrial, agricultural, and residential developments (FSUCML 2014).
According to the Florida Department of Environmental Protection (FDEP), a large
loss of mangrove acreage is attributed to human activities; Tampa Bay has lost
over 44 percent of its coastal wetlands acreage (which includes both mangroves
and salt marshes), Charlotte Harbor has lost 59 percent of its original
mangrove habitat, Lake Worth has lost 87 percent of its mangrove acreage, and
lastly 76 percent of the existing mangrove acreage in St. Lucie Inlet is not
productive to the fishery due to mosquito impoundments (FDEP 2015). With the
great dependence that Goliath grouper have on mangroves, fisheries managers and
the FDEP must take mangrove habitat conservation into account before
considering the potential lift on the harvest ban. Without the appropriate
abundance of quality mangrove environments, lifting the ban could severely harm
the Goliath grouper populations.
Many anglers, divers, and other
members of the Floridian community claim the Goliath grouper are dominating the
area and that the harvest ban should be lifted. Divers have established this
belief due to the large amount of recorded encounters with large abundances of these
fish while diving, which is likely a result of the schooling behavior in the
grouper. Moreover, fishermen have witnessed Goliath grouper stalk and ambush a
fishermen’s catch right off their fishing line. This has resulted in the common
belief that Goliath groupers are “eating all the fish” because occasionally a Goliath
grouper will come and devour a vulnerable fish that’s struggling on the end of
a fishing line. Rather, goliath groupers are simply opportunity seekers, and
will seize an opportunity at an easy meal if one presents itself, such as a
struggling fishing on the end of a fishing line. It’s actually rare for these
fish to consume prey other than crabs and crustaceans (FFWCC 2016). While
Goliath grouper populations have increased significantly since the harvest ban,
lifting the ban now could result in an over-exploitation of the fish and lead
to a large decline in the population.
Juvenile Goliath Grouper Source |
With or without the harvest ban, Goliath
groupers are one of the largest big game fish on the planet, and are sought
after by anglers around the world. Before the ban, the populations were heavily
pressured and over-exploited by fishermen, and as a result, the population
dropped significantly. They were extremely vulnerable to overfishing due to
their lack of fear for humans, their large size, and schooling behavior (Riggs
2009). With the harvest ban in place, fishermen are still able to pursue these goliaths
as long as they are “returned to the water free, alive, and unharmed” (FFWCC
2016) after being caught. With these circumstances in place, the Goliath
grouper population has seen significant growth and recovery; the harvest ban
has assisted the recovery of Goliath grouper significantly. If the harvest ban
is lifted, it is likely that people will harvest the growing population right
back down due to the value of Goliath grouper as a superior big game fish.
In conclusion, there are many
environmental and human factors to consider when considering a potential lift
on the harvest ban of Goliath groupers in the United States. Given the
instability and threats to the species’ habitat and lifestyle, the harvest ban
should not be lifted. If the harvest ban is lifted under the current
circumstances, this could produce a double negative that could drive the
Goliath grouper abundance down significantly. Until there is a substantial increase
in the abundance and quality of mangrove for the Goliath grouper to thrive
throughout, and other influential factors can be deemed stable, the harvest ban
should remain closed.
FDEP (Florida Department of Environmental
Protection). “Mangroves ‘Walking Trees.’” Florida Department of Environmental
Protection http://www.dep.state.fl.us/coastal/habitats/mangroves.htm (accessed
April 14, 2016).
FFWCC (Florida Fish and Wildlife
Conservation Commission). “Goliath Grouper: Epinephalus
itajara.” Florida Fish and Wildlife Conservation Commission http://myfwc.com/fishing/saltwater/recreational/goliath-grouper/
(accessed April 15, 2016).
Frias-Torres, Sarah. 2006. Habitat use of
juvenile goliath grouper Epinephelus
itajara in the Florida Keys, USA. Endangered
Species Research 2:1-6
FSUCML (Florida State University Coastal
and Marine Laboratory). “Global Threats to Goliath Grouper.” FSU Coastal and
Marine Laboratory https://www.marinelab.fsu.edu/labs/ck/grouper-ecology/goliath/threats
(accessed March 17, 2016).
Koenig, Christopher. “Back from the brink:
Atlantic Goliath Grouper recovery in the southeastern United States.” FSU
Coastal and Marine Laboratory https://www.marinelab.fsu.edu/labs/ck/grouper-ecology/goliath/
(accessed April 12, 2016)
Koenig, C. C., F. C. Coleman, A.-M. Eklund,
J. Schull, and J. Ueland. 2007. Mangroves as Essential Nursery Habitat for
Goliath Grouper (Epinephelus itajara).
Bulletin of Marine Science 80(3):567-585.
Riggs, M. 2009. Scaling of Feeding Behavior and Performance in the Goliath Grouper, Epinephelusitajara. Honors College Thesis
project, Western Kentucky University, Bowling
Green, Kentucky.
Shideler, G.S. 2014. Lifting the Goliath
Grouper harvest ban: Angler perspectives and willingness to pay. Fisheries Research 161:156-165
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