United states department of interior bureau of ocean energy management



Download 9.55 Mb.
bet12/15
Sana09.09.2017
Hajmi9.55 Mb.
1   ...   7   8   9   10   11   12   13   14   15

3.9Loggerhead Turtle

3.9.1Description of the Species


The loggerhead sea turtle (Caretta caretta) is one the larger marine turtles; adults average 3 to 7 feet in length and weigh approximately 300 to 1,100 pounds (Dundee and Rossman 1989). This species usually reaches sexual maturity around age 35 and mates between late March and early June in the southeastern U.S.

3.9.2Species Habitat and Distribution


Loggerheads are circumglobal, inhabiting continental shelves, bays, estuaries, and lagoons in temperate, subtropical, and tropical waters. In the Atlantic, the loggerhead turtle's range extends from Newfoundland to as far south as Argentina. During the summer, nesting occurs in the lower latitudes. The primary Atlantic nesting sites are along the east coast of Florida, with additional sites in Georgia, and the Carolinas; some nesting also occurs on the Gulf Coast of Florida. In the eastern Pacific, loggerheads are reported as far north as Alaska, and as far south as Chile. Occasional sightings are also reported from the coast of Washington, but most records are of juveniles off the coast of California. Southern Japan is the only known breeding area in the north Pacific (NMFS 2016).

Loggerheads were the second most abundant sea turtle reported in Louisiana; most of the turtles observed were juveniles (Fuller et al. 1987). Loggerheads are capable of living in a variety of environments, such as in brackish waters of coastal lagoons and river mouths. During the winter, they may remain dormant, buried in the mud at the bottom of sounds, bays, and estuaries. The major nesting beaches are located in the southeastern United States, primarily along the Atlantic coast of Florida, North Carolina, South Carolina, and Georgia. Only minor and solitary nesting has been recorded along the coasts of the GOM. In 2015 for example, USGS recorded crawl attempts during the nesting season at the Chandeleur Islands and the Louisiana Department of Wildlife and Fisheries (LDWF) located a nest crawl on Grand Isle.

The largest of the hard-shell sea turtles, the loggerhead is distributed worldwide in temperate and tropical bays and open oceans. Loggerheads probably range all along the Louisiana coast; however, Dundee and Rossman (1989) reported specimens only from Chandeleur Sound, Barataria Bay, and Cameron Parish. The population decline of loggerheads can be attributed to egg and nestling predation by mammals and birds (Dundee and Rossman 1989).

Nesting on the Gulf Coast occurs between the months of April and August, with 90 percent of the nesting effort occurring on the south-central Gulf Coast of Florida (Hildebrand 1981). Although loggerheads have been documented as nesting on the Chandeleurs in 1962 and Grand Isle in the 1930s, it is doubtful whether this species currently successfully nests on the Louisiana coast (Hildebrand 1981, Dundee and Rossman 1989). The loggerhead's diet includes marine invertebrates such as mollusks, shrimp, crabs, sponges, jellyfish, squid, sea urchins, and basket stars (Caldwell et al. 1955; Hendrickson 1980; Nelson 1986). Landry (1986) suggested that these turtles may also feed on discarded by-catch from shrimp trawling. Adult loggerheads feed in waters less than fifty meters deep, while the primary foraging areas for juveniles appears to be in estuaries and bays (Nelson 1986; Rabalais and Rabalais 1980).

During the construction of the Caminada Headlands Beach and Dune Restoration Project (BA-45), turtle trawling and relocation was conducted in conjunction with hopper dredging activities in the South Pelto Borrow Area. Of the total 154 sea turtle relocations, 69 Loggerhead sea turtles were relocated as a part of the project activities. There were no turtle mortalities or injuries associated with relocation trawling on this project (Coastwise Consulting, 2014). There was one incidental take involving a Loggerhead sea turtle aboard one of the hopper dredges as part of this project (REMSA, 2014).

During the construction of the Caminada Headlands Beach and Dune Restoration Increment II Project (BA-143), turtle trawling and relocation was conducted in conjunction with hopper dredging activities in the South Pelto Borrow Area. This netted 40 relocations of 40 different sea turtles. A total of 7 Loggerhead sea turtles were relocated as a part of the project activities. There were no turtle mortalities or injuries associated with relocation trawling on this Project (East Coast Observers, 2014). There were zero incidental takes during the hopper dredge operation of the Caminada Headland Increment II Project (REMSA, 2016).

The Caminada Headland Beach and Dune Restoration Projects clearly established the presence and high abundance of Loggerhead Sea Turtles in the South Pelto portion of Ship Shoal.

3.9.3Status and Cause of Decline


The loggerhead sea turtle was listed as a threatened species on July 28, 1978 (43 FR 32800). Critical habitat was designated for the North Atlantic Ocean Distinct Population Segment on July 10, 2014 (79 FR 39755).

Loggerhead turtle biology, behavior, and conservation were summarized by Perrine (2003) and Spotila (2004). Loggerheads can live in a variety of environments, including brackish waters of coastal lagoons and river mouths. During the winter, they may remain dormant, buried in the mud at the bottom of sounds, bays, and estuaries. Most nesting beaches are in the southeastern U.S., primarily along the Atlantic coast from Florida to North Carolina. Infrequent nesting occurs along the Gulf coast.

The loggerhead is the most abundant sea turtle species in U.S. waters. Nearshore Gulf waters may provide important developmental habitat for juvenile loggerheads. Loggerheads stranded on the lower Texas coast (south of Matagorda Island) appear to have been feeding in nearshore waters shortly before their death (Plotkin et al. 1993).

Major protection efforts of nests and beach habitat protection are underway for most of the significant nesting areas in the southeast U.S. and mortality from commercial fisheries have been reduced with the enforcement of turtle excluder devices (TED) regulations. Many coastal counties and communities in Florida, Georgia, and South Carolina have developed lighting ordinances to reduce hatchling disorientation. Important U.S. nesting beaches are being acquired for long-term protection. Loggerhead turtles migrate, this severely compromises conservation efforts for turtles outside U.S. waters. Legal and illegal fishing in some countries cause high mortality of loggerhead nesting populations in the western north Atlantic. Long migrations between nesting beaches and foraging areas requires long-term international cooperation to enable recovery and stability of nesting populations (USFWS 2001e).



Download 9.55 Mb.

Do'stlaringiz bilan baham:
1   ...   7   8   9   10   11   12   13   14   15




Ma'lumotlar bazasi mualliflik huquqi bilan himoyalangan ©hozir.org 2020
ma'muriyatiga murojaat qiling

    Bosh sahifa
davlat universiteti
ta’lim vazirligi
O’zbekiston respublikasi
maxsus ta’lim
zbekiston respublikasi
o’rta maxsus
davlat pedagogika
axborot texnologiyalari
nomidagi toshkent
pedagogika instituti
texnologiyalari universiteti
navoiy nomidagi
samarqand davlat
guruh talabasi
ta’limi vazirligi
nomidagi samarqand
toshkent axborot
toshkent davlat
haqida tushuncha
Darsning maqsadi
xorazmiy nomidagi
Toshkent davlat
vazirligi toshkent
tashkil etish
Alisher navoiy
Ўзбекистон республикаси
rivojlantirish vazirligi
matematika fakulteti
pedagogika universiteti
таълим вазирлиги
sinflar uchun
Nizomiy nomidagi
tibbiyot akademiyasi
maxsus ta'lim
ta'lim vazirligi
махсус таълим
bilan ishlash
o’rta ta’lim
fanlar fakulteti
Referat mavzu
Navoiy davlat
umumiy o’rta
haqida umumiy
Buxoro davlat
fanining predmeti
fizika matematika
universiteti fizika
malakasini oshirish
kommunikatsiyalarini rivojlantirish
davlat sharqshunoslik
jizzax davlat