Scalloped Hammer Head
http://www.underseahunter.com/images/bereiche/art000038_scalloped-hammerhead_burns.jpg
Sphyrna lewini
or the Scalloped Hammerhead is in the family Sphyrnidae with all other species
of shark with the distinct “hammer head”. The scalloped hammerhead is one of
the largest in the family with mature females sometimes growing to over 13
feet. Mature males reach sexual maturity around 6 feet in length, where as
females reach sexual maturity at 8.2 feet on average.
Despite what there endangered listing
suggests, Scalloped hammerheads have relatively high fecundity compared to
other sharks, giving live birth to litters of around 15-30 infants. This is
probably because there is a very high infant mortality rate for the young,
where only the fittest survive. Like many sharks the scalloped hammerhead
mothers do not provide much parental care. Scalloped hammerheads give birth to
many young, but growth is very slow and sexual maturity is not reached until a
late age, sometimes around 15 years. This leaves shark populations at extreme
vulnerabilities to mortality by fishing. Scalloped hammerheads generally only give
birth once a year. Young hammerheads typically return to their birth site
frequently.
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Scalloped hammerheads navigate a huge
range of waters compared to some sharks. These sharks are distributed in waters
from the surface to depths of 900 feet. Typically the young sharks stay towards
the surface however. This puts younger sharks at higher risk of fishing
mortality around the globe. Scalloped hammerheads have been known to patrol the
ocean alone, or in massive schools reaching 100 sharks. Schools of hammerheads
can effectively hunt larger and trickier prey compared to lone sharks.
Typically these sharks eat a wide range of fish including herring, mackerel,
sardines, and even octopus, squid, and rays. Larger adults however have been
known to prey on smaller shark species such as black tip reef sharks, and Atlantic
sharp nose sharks.
Scalloped hammerheads are distributed
in waters all around the globe, in coastal warm temperate and tropical seas.
Many distinct populations have been designated and none of them show promising
results in terms of population trends. The Northwest and Western Central
Atlantic (including Caribbean Sea) estimates of trends in abundance
are available from two long-term research surveys conducted on the U.S. east
coast. Both surveys conveyed a depressing decline of species in the region of
up to 98% from 1978 to 2003. Another survey compared fishing catching rates
from 1983-4 with catching rates from 1993-5 and showed a decline of 66%. Scalloped hammerheads have been listed as
endangered in this area.
In the Western Indian Ocean scalloped hammerhead populations have
decreased by 64%. This figure comes from shark nets off beaches in Kwa-Zulu
Natal, South Africa, where the per unit shark catch rate has declined rapidly
from 1978-2003. Scalloped hammerheads face heavy fishing pressures throughout
the Indian Ocean. The hammerhead is also heavily targeted by some fisheries
because of the high number of fins compared to other sharks. Because of the
continued high fishing pressure this sub species of scalloped hammerhead is
listed as endangered by the red list. A similar situation is present in the Eastern Central and Southeast Pacific,
as these hammerheads are heavily fished as well. Areas of particular concern
are adult aggregating sites where many hammerheads return from migration each
year. Spots such as these include Cocos Island (Costa Rica) and the Galapagos
Islands (Ecuador), and along the slopes of the continental shelf where high
catch rates of juveniles can be obtained. These spots have been seeing very
high increases in fishing for sharks. The Galapagos in particular is suspect of
hammerhead targeting fishing practices because of the high value of its fins.
Divers and dive guides in the Galapagos have reported sever declines in sharks
and shark schools in the area, presumably from the high fishing pressures. The
scalloped hammerhead is also listed as endangered in this area by the ESA.
The scalloped hammerhead is
the first species of shark to be listed on the Endangered Species Act by the National Marine Fisheries Service (NMFS). This shark was listed as Endangered on the red list,
but has just recently been acknowledged by the ESA in July of 2014. The ESA
listed a few distinct populations as threatened,
Central and Southwest (SW) Atlantic Distinct Population Segment (DPS) and the
Indo-West Pacific DPS of scalloped hammerhead shark. In addition they listed
the Eastern Atlantic DPS and Eastern Pacific DPS of scalloped hammerhead sharks
as endangered species under the ESA.
The cause of the listing has
been attributed almost entirely to fishing pressures. Hundreds of millions of
sharks are caught purposely and as by catch each year around the globe. Sharks
are purposely caught because their fins are very valuable. These fins are
prized, as they provide a huge demand in Asia for a single dish called shark
fin soup. Scalloped hammer heads are particularly targeted and prized because
they have more fins, and larger fins than other sharks. The “finning” practice
of sharks is brutal, where fishermen catch hundreds of sharks, cut the fins
off, and toss the shark back into the ocean to die. The shark can no longer
swim and drowns when water can no longer be pushed past its gills.
Taken from national geographic
No particular recovery plan has
been documented yet by the ESA as the species is relatively new to the ESA
list, but many actions have been taken place and are being taken place right
now:
A proposed rule by the National
Oceanic and Atmospheric Administration on 04/05/2013 titled, “Endangered and Threatened Wildlife and
Plants; Proposed Endangered, Threatened, and Not Warranted Listing
Determinations for Six Distinct Population Segments of Scalloped Hammerhead
Sharks” reports the following conservation methods:
CITES
“Convention on International
Trade in Endangered Species of Wild Fauna and Flora (CITES) Conference of the
Parties meeting in Bangkok, countries agreed to increase protection for five
commercially-exploited species of sharks and manta rays.”
http://www.fisheries.noaa.gov/ia/slider_stories/2013/02/cites_cop16.html
“In 2012, S. lewini was
submitted for inclusion on CITES Appendix III by Costa Rica, and is now
effectively listed in the appendix. An Appendix III listing allows
international trade of the species, but provides a means of gathering trade
data and other relevant information. For example, the export of S.
lewini specimens from Costa Rica requires a CITES export permit issued
by the Costa Rica CITES Management Authority.”
U.S.
Fishery Management: Amendment 5 to the Consolidated HMS FMP
“On
April 28, 2011, NMFS determined that the Northwest Atlantic and Gulf of Mexico
scalloped hammerhead shark stock was overfished and experiencing overfishing (76 FR 23794; April 28,
2011).” https://www.federalregister.gov/articles/2013/04/05/2013-07781/endangered-and-threatened-wildlife-and-plants-proposed-endangered-threatened-and-not-warranted#h-60
“NMFS is currently in the process of
finalizing Amendment 5 to the Consolidated HMS FMP (proposed on November 26,
2012, 77 FR 70552; public comment period closed February 12, 2013), which
will prescribe management measures and implementing regulations to conserve the
scalloped hammerhead shark NW Atlantic GOM DPS.”
“Specifically, NMFS will establish
annual catch limits and accountability
measures for the scalloped hammerhead shark stock to allow for rebuilding
of the stock. With fishery rebuilding plans, there is an explicit time frame
for achieving this conservation effort, which will be stated in the Amendment
to the FMP.”
“NMFS is working to develop a rebuilding plan that will set
specific quota and retention limits for scalloped hammerhead sharks and allow
for the recovery of these sharks in the Northwest Atlantic and Gulf of Mexico.”
Shark Fin Ban
“In the United States, California, Oregon, Washington, and
Hawaii have already passed legislation banning the sale, possession, and
distribution of shark fins.”
“The push to stop shark finning and
curb the trade of shark fins is also evident overseas and most surprisingly in
Asian countries, where the demand for shark fin soup is highest.”
“Taiwan, the third top exporter of shark fins to Hong Kong in
2008, banned the practice of shark finning at sea in 2012. Likewise, many
hotels in Taiwan, such as the W Taipei, the Westin Taipei, and the Silks Palace
at National Palace Museum, also vowed to stop serving shark fin dishes as part of
their menus.”
“In November of 2011, the Chinese
restaurant chain South Beauty removed shark fin soup from its menus, and in
2012, the luxury Shangri-La Hotel chain joined this effort, banning shark fin
from its 72 hotels, most of which are found in Asia.”
“
While an official recovery plan is
still on the way from the ESA, the scalloped hammerhead has actions in place to
help insure its populations can return to the once prolific rates they were.
My person action involves writing a
letter to CITES to get Scalloped hammerheads on appendix 1. Right now scalloped
hammerheads are found on appendix II, which means federal trade is legal, but
with restrictions. My proposed plan hopes to land scalloped hammerheads on
schedule I making the trade of these creature’s fins completely illegal
internationally. I would like you to
address your concerns for the dwindling number of hammerhead sharks and address
the vital roles these creatures play as apex predators in the ocean.
Cites can be contacted here at:
CITES Secretariat
International Environment House
11 Chemin des Anémones
CH-1219 Châtelaine, Geneva
Switzerland
Tel: +41-(0)22-917-81-39/40
Fax: +41-(0)22-797-34-17
Email: info@cites.org
International Environment House
11 Chemin des Anémones
CH-1219 Châtelaine, Geneva
Switzerland
Tel: +41-(0)22-917-81-39/40
Fax: +41-(0)22-797-34-17
Email: info@cites.org
Together hopefully we can ban the vile
and inhumane trade of shark fins to save not only this beautiful species of
shark, but all sharks.
Ferretti, Francesco, et al. "Patterns And Ecosystem
Consequences Of Shark Declines In The
Ocean." Ecology Letters 13.8
(2010): 1055-1071. Academic Search
Premier. Web. 27 Oct. 2015.
Clarke, Shelley C., et al. "Population Trends In
Pacific Oceanic Sharks And The Utility Of Regulations On Shark
Finning." Conservation Biology 27.1 (2013):
197-209. Academic Search Premier. Web. 27 Oct. 2015.
Sembiring, Andrianus, et al. "DNA
Barcoding Reveals Targeted Fisheries For Endangered
Sharks In Indonesia." Fisheries Research 164.(2015): 130-134. Academic Search Premier.
Web. 7 Nov. 2015.
Rizzari, Justin R., Brock J. Bergseth, and
Ashley J. Frisch. "Impact Of Conservation Areas
On Trophic Interactions Between Apex Predators And Herbivores On Coral Reefs." Conservation
Biology 29.2 (2015): 418-429. Academic Search Premier. Web. 27 Oct. 2015.
"Endangered and Threatened Wildlife and Plants; Proposed Endangered, Threatened, and Not Warranted Listing Determinations for Six Distinct Population Segments of Scalloped Hammerhead Sharks." NOAA. 5 April 2015. 30 Nov 2015. https://www.federalregister.gov/articles/2013/04/05/2013-07781/endangered-and-threatened-wildlife-and-plants-proposed-endangered-threatened-and-not-warranted#h-60
