Sea turtles, inhabiting the world’s oceans for 150 million years, have survived natural climate change events including the last Ice Age. But the current pace of climate change will be faster than anything experienced in the last 10,000 years, and therefore is an unprecedented threat to sea turtles whose populations are already vulnerable from human activities.
While climate change may not have led to the current decline of sea turtles, climate change impacts are now being seen, and it is a serious problem that must be addressed to help protect these ancient ocean dwellers from disappearing forever. Sea turtle populations are already vulnerable and the additional impacts from climate change will further hamper the recovery of sea turtle populations to healthy levels.
Climate change will impact sea turtles in the following ways:
- Loss of nesting beaches and coastal habitat through rising sea levels, an increase in storm surges, eroding shorelines, and coastal barrier projects;
- Increased female gender bias in hatchlings;
- Reduced hatching success from high temperatures and increased storm events
- Decreased or shifting food supply; and
- Changing ocean currents impacting migration.
One impact of sea level rise is the loss or diminishment of beaches, including those on which sea turtles nest.
In this report, we examine the impacts of sea level rise on major sea turtle nesting beaches for the seven species of sea turtles. From existing data and sea level rise projections, we have identified two major US nesting beach areas that are at risk from climate change: French Frigate Shoals in Hawaii and Padre Island National Seashore in Texas.
The California driftnet fishery has an overall negative impact on our economy because it costs more to manage the fishery than the wealth that is created from the fishery.
Taxpayers pay for observers and regulators for fisheries to protect public marine resources. Because driftnets are inherently destructive, tight regulation is necessary to ensure that the fleet complies with U.S. and California law and that the fishery does not devastate the public marine resources of the California coast. The cost of regulation would substantially decrease if the California swordfish fishery used more sustainable fishing gear instead of driftnets.
The catch from the California driftnet fishery peaked in the 1980s and has been steadily declining.1 According to the California Department of Fish and Wildlife, the California driftnet fishery landed 135,000 pounds of swordfish in 2013, valued at $585,000.
Sea turtles are among the most ancient of living species, having evolved during the age of the dinosaurs some 110 million years ago. Today, seven species survive. All sea turtles found in U.S. waters are listed as ‘endangered’ or ‘threatened’ under the U.S. Endangered Species Act. Importantly, the two main species killed by the driftnet fishery – the Pacific Loggerhead and the Leatherback – are both endangered and in imminent peril of extinction.
Sea turtles reach a large size as adults, making them immune to most natural predators and allowing females to produce thousands of young over their long reproductive lives, despite the fact that relatively few will survive to adulthood. This successful evolutionary strategy has worked for millions of years, but is now being short-circuited when adult sea turtles are killed in industrial fishing gear. Sea turtles are now endangered worldwide.
SPAWN, National Park Service, and Marin Municipal Water District (MMWD) are part of the team counting and monitoring the numbers of fish migrating to their natal streams to spawn and lay eggs. SPAWN monitors these fish in the San Geronimo Valley’s small tributaries, specifically Arroyo, El Cerrito, Barranca, Montezuma, Larsen, Willis Evans, Woodacre, and North Fork San Geronimo creeks. Below is our brief overview of the data collected this spawning season in our watershed.
This season a total of 271 coho redds were observed throughout our watershed.
For the first time in recent years, the timing and amount of rainfall allowed our coho salmon to make their way into some of San Geronimo’s smaller tributaries. SPAWN documented a total of 30 coho salmon redds (nests) this season in the San Geronimo tributaries, but they were all in just two of the eight tributaries, with 17 redds recorded in Arroyo Creek, and 13 redds in Woodacre Creek.
These two small tributaries accounted for 30 percent of the total 99 spawners for the San Geronimo Valley and 11 percent of all the redds in the Watershed (which includes Lagunitas Creek, Devils Gulch, Cheda Creek, San Geronimo Creek and all seven San Geronimo tributaries).
While media reports have stated the run count of 271 is the best in ten years, what may be more biologically relevant is the fact that the spawning numbers for this year-class are below its 311 average.
These fish live and die in a three year period, so there are basically three distinct year-class populations. If you look at the year-class that spawned this year, and compare it against those 3 years ago, six years ago, nine years ago, etc., it is below average. Scientists do not normally try to draw conclusions about population trends from a single year’s data point.
The stated U.S. National Marine Fisheries Service recovery goal is to bring the runs of these imperiled fish to average 2,600 adult fish each and every year.
In Marin, the species is on the verge of extinction, no matter how the numbers are spun. This year, our creeks and tributaries did provide spawning grounds to a few more fish than last year, but more must be done to ensure these fish not only survive but thrive.
Kemp’s ridley sea turtles (Lepidochelys kempii) are the smallest and most vulnerable species of sea turtle in the world (1,2). They weigh only 100 pounds at most in adulthood and get up to 2 feet long (1,3). Kemp’s ridleys have a limited habitat, nesting in just two countries in the Gulf of Mexico (3). This means that the Kemp’s ridley is particularly vulnerable to localized threats like commercial fishing, egg harvesting, and oil spills (1,2,3).
A Lifetime of Turtlehood
This tiny species makes a dramatic entrance come nesting season. Kemp’s ridley nest in ‘arribadas.’ Spanish for arrival, arribadas are a spectacle to witness. Wave upon wave of females come crashing ashore, laying their eggs in broad daylight unlike any other sea turtle in the world (1,4). From April to July, females will do this up to three times, burying approximately 100 eggs each time in freshly dug holes on beaches in Mexico, Texas, and Florida (1,2,3).
Little hatchlings emerge from their holes in the sand after two months of incubation and head straight for the open ocean, eager to evade any near-shore predators that might be lurking (1). For the first two years of their lives, hatchlings ride the tides up and down the Atlantic coast, from as far north as Nova Scotia and as far south as Bermuda (1,2,4).
After two years of travelling the coast, adolescent Kemp’s ridleys return to the Gulf of Mexico (1,2). Here, they forage for swimming crabs and other hard foods, rarely diving deeper than 160 feet during their adult life. Some will migrate in search for food but, come adulthood, Kemp’s ridleys are not known to wander far (1).
After ten years of living in the Gulf, Kemp’s ridleys reach sexual maturity. Like their parents before them, they return to important nesting sites in Mexico, Texas, and Florida to lay their eggs (1).
Struggling to Survive
Kemp’s ridley sea turtles are listed under the US Endangered Species Act and as IUCN Critically Endangered (2,3). They are more endangered than any other species of sea turtle (1). Slowly, though, Kemp’s ridley populations are recovering (1,2).
Much of the initial decline in Kemp’s ridleys was due to direct harvesting of eggs and adult turtles. Most Kemp’s ridleys lay their eggs at the same time on a single stretch of beaches in Tamaulipas, Mexico. Their eggs are thus extremely concentrated, making them an easy target for harvest and costing their population tens of thousands of turtles in the early 1900s (4). Egg harvesting was made illegal in 1966, and this threat was significantly reduced (1,2).
Kemp’s ridleys’ greatest threat is the commercial fishing industry. In particular, shrimp trawls have damaged their population quite dramatically by indiscriminately scooping up and jeopardizing the lives of everything in its path, including sea turtles. Fortunately, the shrimp industry is now required to use Turtle Excluder Devices (TEDs) in both the U.S. and in Mexico. These devices allow sea turtles to escape through a hatch in the nets, and they have greatly reduced sea turtle mortality from shrimp fisherman (1,2). Still, sea turtles continue to get caught and die in shrimp trawl nets.
Since the enactment of harvest and commercial fishing limitations, Kemp’s ridleys have been able to recover to a small extent. Current setbacks to their recovery include beach traffic and development. Development disturbs nesting beaches by introducing things like seawalls and sand renourishment projects that impact the sand on which sea turtles nest. Another consequence of development is beachfront lighting, which attracts young hatchlings away from the moonlit ocean and into roads (3).
Pollution poses another serious threat to Kemp’s ridleys. Sea turtles have a hard time distinguishing plastic bags and other litter from food. When consumed, this litter becomes lodged in their digestive system and, eventually, will lead to death (3). Contaminants such as oil additionally impact Kemp’s ridleys. Following Deepwater Horizon, 600 sea turtles were found dead, 75% of which were Kemp’s ridleys (5).
- (2015) Kemp’s Ridley Turtle (Lepidochelys Kempii). NOAA Fisheries. <http://www.nmfs.noaa.gov/pr/species/turtles/kempsridley.html>
- North Florida Ecological Services Office (2015) Kemp’s Ridley Sea Turtle (Lepidochelys Kempii). U.S. Fish and Wildlife Service. <https://www.fws.gov/northflorida/seaturtles/turtle%20factsheets/kemps-ridley-sea-turtle.htm>
- Conservation Commission (2012) Kemp’s Ridley Sea Turtle (Lepidochelys Kempii). Florida Fish and Wildlife. <http://myfwc.com/media/2212153/Kemps-ridley-sea-turtle.pdf>
- Conservation Commission (1999) Kemp’s Ridley Sea Turtle (Lepidochelys Kempii). Florida Fish and Wildlife. <http://www.ct.gov/deep/cwp/view.asp?a=2723&q=326026>
- (2014) 2010 Gulf Of Mexico Oil Spill: Sea Turtles, Dolphins, And Whales. NOAA Fisheries. <http://www.nmfs.noaa.gov/pr/health/oilspill/gulf2010.htm>
Loggerhead sea turtles (Caretta caretta) get their name from their enormous heads (1,3). Their bodies are similarly large, earning them the title of the largest hard-shelled sea turtle. This red-brown species typically grows up to 3.5 feet long and can weigh from 400 pounds to as much as 1,000 pounds (1).
Loggerheads are listed as ‘Threatened’ under the U.S. Endangered Species Act (ESA). Due to commercial fishing and other activities, their populations are quickly dwindling towards endangerment (1,2,4).
How They Live
Loggerhead sea turtle distribution. Photo Credit: NOAA, via Wikimedia Commons
Female loggerheads produce and bury an average of 100 eggs each nesting season (1,5). They prefer subtropical and temperate waters in the Mediterranean Sea and Indian, Pacific, and Atlantic Oceans. In the United States, loggerheads nest on the Atlantic Coast from Texas to New Jersey during the summer and early fall (2,3). To protect their eggs during incubation, nesting females dig large holes with a side chamber, where the eggs are laid and then buried (1).
Loggerheads dig a huge holes with chambers in which to lay their eggs. Photo Credit: Hillebrand Steve, USFWS
During their two months of incubation, surrounding temperatures determine whether a hatchling will emerge a male or a female – warmer temperatures yield female hatchlings, while cooler temperatures yield males (1,5). Once the hatchlings emerge they follow the moonlight out to the ocean where they grow to adulthood feeding on both hard-shelled and soft-bodied prey. When female loggerheads reach 20 years old, they return to the beaches on which they were lain and begin the cycle anew (1).
Photo Credit: U.S. Fish and Wildlife Service, via Wikimedia Commons
Why They’re Declining
Loggerhead sea turtles are classified as a ‘Vulnerable’ species by the IUCN and listed as ‘Threatened’ by the EPA (1,2,4). Their populations are in continual decline (4).
Incidental catch by industrial fishing operations is the primary cause of loggerhead decline worldwide. In the case of commercial shrimping, vessels targeting shrimp use large trawl nets. These nets indiscriminately scoop up everything in their path, including sea turtles. In the U.S., shrimp fishermen must use Turtle Excluder Devices (TEDs). These devices allow sea turtles to escape through a hatch in the nets. This has reduced the threat caused by commercial fisheries, but not eliminated it (1,4).
Another factor contributing to the loggerheads continual decline is the loss and destruction of nesting beaches. As human development encroaches further and further onto beaches and sea levels rise, the space left for loggerheads is slowly squeezed out (1,3,4,5). The habitat that is left is subject to heavy predation, by humans, natural predators, and introduced species. In some cases, raccoons have been known to destroy more than 95 percent of nests on a single beach (3).
Photo Credit: MoodyGroove at en.wikipedia
Eggs that are fortunate enough to escape predation hatch, and face a host of new dangers. Light emitted from city glow, street lamps, and other exterior lighting disorients hatchlings that mistake it for the moonlit ocean. Disoriented, many loggerhead hatchlings head straight for the road (2,4). Hatchlings that make it to the ocean are forced to seek shelter from natural predators in pollutant-accumulating aquatic vegetation (5). Pollution will remain a threat throughout a loggerhead’s lifetime, as items such as balloons, plastics, and monofilament fishing line catch in their digestive system. Larger boating and fishing gear entanglement and boat strikes also pose serious threats to loggerhead sea turtles (1).
- Biscayne National Park Florida (2013) Lights Out For Loggerheads. South Carolina DNR. <https://www.nps.gov/bisc/learn/nature/species-focus-loggerhead-sea-turtles.htm>.
- Marine Turtle Conservation Program (2013) Lights Out For Loggerheads. South Carolina DNR. <http://www.dnr.sc.gov/seaturtle/lights.htm>.
- Endangered Species Unit (2016) Loggerhead Sea Turtle Fact Sheet. NYS Dept. of Environmental Conservation. <http://www.dec.ny.gov/animals/7156.html>.
- Casale P, Tucked AD (2015) Caretta caretta. The IUCN Red List of Threatened Species 2015: e.T3897A83157651 <http://www.iucnredlist.org/details/3897/0>.
- Partymiller L (2016) Species Profile: Loggerhead Sea Turtle (Caretta Caretta) | SREL Herpetology. UGA Savannah River Ecology Lab. <http://srelherp.uga.edu/turtles/carcar.htm>.
Climate change and the resulting sea level rise are threatening key sea turtle nesting beaches around the world. As all seven species of sea turtles are already under threat, loss of key nesting beaches could be detrimental to turtle populations if rapid action is not taken. Read our fact sheet to get the important details from our full report, ‘Deadly Waters: The Threat of Climate Change and Rising Sea Levels to Sea Turtle Nesting Beaches.’
Climate Change: A Rising Tide
The current pace of climate change will be faster than anything experienced in the last 10,000 years, and therefore is an unprecedented threat to sea turtles whose populations are already vulnerable from human activities. Specifically, climate change will cause a loss of nesting beaches and coastal habitat through rising sea levels, increased female gender bias in hatchlings, reduced hatching success from high temperatures and increased storm events, decreased or shifting food supply, and changing ocean currents impacting migration.
Sea Turtle Nesting Behavior
Sea turtles return to their birthplace to lay eggs, breed and nest. When mature, the female turtles return to their natal beaches to nest. This is problematic if these beaches disappear as a result of sea level rises.
- Hawaiian sea turtles are at risk.
- 90 percent of green sea turtles (Chelonia mydas) nest in Hawaii on the French Frigate Shoals, part of an atoll located in the Northwestern Hawaiian Islands. This area could disappear due to sea level rise.
- Loggerhead sea turtles could lose 43 percent of their nesting habitat in Florida, where more than 10,000 females nest each year. This percentage is based on a model that assumes half meter sea level rise within the next 20 to 50 years.
- Texas sea turtles are at risk.
- Padre Island National Seashore in Texas is the second most important nesting site for the Kemp’s ridley sea turtle in the world, and is vulnerable to storm surges and rising sea levels.
- Further research needs to be conducted to survey beach profiles and overlay that data with models of projected sea level rises and storm surges to identify the level of risk from climate change for olive ridley, hawksbill and flatback sea turtles.
- Ensure Major Nesting Beaches are Climate Resilient
- Establish Second Nesting Colonies at Key Species Nesting Sites
- Reduce Other Anthropogenic Threats to Sea Turtles at Priority Nesting Beaches
- Document Potential Loss of Major Sea Turtle Nesting Beaches Worldwide
- Reduce Climate Change Emissions to Bring Carbon Dioxide Levels Below 350 Parts Per Million
Read the full report here: https://seaturtles.org/deadlywaters/
- Hawaiian sea turtles are at risk.
Common Name: Silky Shark
Scientific name: Carcharhinus falciformis
-One of the three most common pelagic sharks in the world, and most common shark in tropical pelagic fisheries.
-Present in global tropical waters between latitudes 20° N and S.
-Inhabits both oceanic and coastal habitat.
Facts About Silky Sharks:
-Name comes from its smooth skin and slim body
-Commonly reaches a length of 2.5 m (8.2 ft), with a maximum recorded length of 3.5 m (11 ft) and weight of 346 kg (763 lb)
-An opportunistic predator, feeding on squid, tuna, mackerel, sardines, groupers, and snappers.
International consensus agrees on the precarious state of the population by overfishing, judging by the low in relative abundance and reducing size of specimens caught in fisheries where data exist.
-Total annual catch reported to the Food and Agricultural Organization fell steadily from 11,680 tons in 2000 to 4,358 tons in 2004
-Declines of some 90% in the central Pacific from the 1950s to the 1990s
-60% decline off Costa Rica from 1991 to 2000
-91% decline in the Gulf of Mexico from the 1950s to the 1990s
-85% decline (for all large requiem sharks) in the northwestern Atlantic from 1986 to 2005
-The silky shark fishery off Sri Lanka reported a drop from a peak catch of 25,400 tons in 1994 to only 1,960 tons in 2006
IUCN Red List Category: Vulnerable in the Eastern, Central, and Southeast Pacific, and Northwest and Western Central Atlantic. Near Threatened on a global scale.
Convention on Migratory Species Status: Listed under Appendix II in November of 2014, and listed under Annex I of the Memorandum of Understanding (MoU) Migratory Sharks in February 2016.
-Greatest numbers of silky sharks are caught incidentally by tuna and mahi mahi longline and purse seine fisheries throughout its range, particularly those using fish aggregating devices.
-Most-caught species in longline fisheries in the Eastern Tropical Pacific, constituting up to 90% of the total catch of sharks.
-Large numbers of silky sharks caught by commercial and artisanal multispecies shark fisheries operating off Mexico, Guatemala, El Salvador, Costa Rica, the United States, Ecuador, Spain, Portugal, Sri Lanka, the Maldives, Yemen, and Côte d’Ivoire.
-Fins from an estimated 0.5 to 1.5 million silky sharks are traded globally per year; it is the second- or third-most common species auctioned on the Hong Kong fin market, which represents over half the global trade
-The meat (sold fresh or dried and salted), skin, and liver oil may also be used
-Predominant source of dried shark jaw curios sold to tourists in the tropics
Recommended conservation actions
-The IATTC should enact the recommendations of its Scientific Advisory Committee to reduce and limit the catch and implement 3-month fisheries closures
-CITES should list the Silky Shark on Appendix II and trigger measurable action plans to reduce mortality and reverse population decline
-Reduce fishing effort in the Eastern Tropical Pacific
-Release sharks alive
For Kids & Classes
Join our Coho Photo Campaign!
Easy as 1,2,3…..
1) Take a photo holding up a sign that says why you think it is important to protect coho.
2) Upload your photo to social media and use the hashtag #SAVEMARINSCOHO
3) Get your friends to join, and exponentially increase your impact!
Below is the link to our sentence starter but feel free to make your own: PhotoCampaign_coho
Please make sure to share it with us on Facebook! https://www.facebook.com/salmonprotection?fref=ts
- 1 or 2 large cardboard box/cartons. I get these from appliance stores or bicycle shops
- 8 1-2″ wide strips of fabric about 1-2 ft. long. I got fabric from a thrift shop, old sheets or bed spreads work well for this (try to find a color that is similar to your turtle).
- Quart of exterior house paint (possibly some Z-prime for an undercoat depending on quality desired).
- A heavy-duty stapler with 3/8″ staples. Stapler needs to be the long handled heavy duty type. Staples longer than 3/8″ tend to bend and come back through the cardboard creating a sharp, snagging hazard.
Click here to download and view the full instructions.
Sea Turtle Costumes in Action (pictured below):
Cocos Island National Park in Costa Rica is known worldwide as an ocean haven for spectacular sharks, rare sea turtles, whales and abundant marine wildlife. But even World Heritage status has not stopped commercial fishers from invading these treasured waters.
Turtle Island is working to demand that Costa Rica protect Cocos Island National Park create a protected area that connects all the way to Ecuador’s waters, northeast of the Galapagos Islands. These two nations could create one of the world’s largest protected ocean zones, and save the endangered leatherback turtle from extinction.
And now you can help us! We welcome experienced divers who want to participate in our ongoing research to help tag and track sea turtles and sharks in the Cocos Islands. You will get hands-on opportunities to capture turtles and attach satellite and acoustical transmitters and to tag and photograph hammerhead sharks underwater.