User:Emeraldh01/Sea turtle migration

Physiological and Behavioral Aspects of Sea Turtle Migration
Sea turtles are known to migrate long distances up to 10,000 miles or more per year. During this time of travel, there is movement between breeding, foraging, and overwintering sites. Migration begins at the time of hatching. Hatchlings begin to migrate to open waters after emerging from their nest. Juvenile and adult sea turtles engage in seasonal migration, likely due to finding other thermal habitats and seeking areas with sufficient food availability. Sea turtles will move north during spring and summer seasons to more nutrient rich bodies of water. In fall and winter seasons, they will migrate back in a southward direction. Sea turtles are considered ectothermic non-avian reptiles. Temperature plays a major affect on both metabolic and physiological process of the turtle. During sea turtle migration, it has been shown that there is a correlation between activity levels and VO2 within the turtles. Previous research concludes that VO2 levels are higher when in migration rather than in rest. The size of the turtles also have an effect on aerobic metabolism levels. A previous study indicated that as body size of the sea turtles increased, so did the capacity for aerobic activity. The higher capacity of aerobic activity is effective when traveling long distances. The research team concluded that the migrations done by the sea turtles are helpful in regulating temperatures, which overall increases their aerobic metabolic activity.

The following navigational methods of sea turtle migration help to increase the fitness benefits of the sea turtle. The turtles use these cues to travel into deeper waters for more a higher abundance of food and a lower risk of predation. For sea turtles who are endangered, finding an area of lower predation helps to maximize their overall fitness and keep them as an existent species.

Navigation methods
Turtle navigational skills for migrations remain unknown. There are several hypotheses including astronomical cues and the Earth's magnetic field. There is evidence that sea turtles do use a navigational compass such as bicoordinate mapping or geomagnetic imprinting when making long migrations. The following navigational methods of sea turtle migration help to increase the fitness benefits of the sea turtle. The turtles use these cues to travel into deeper waters for more a higher abundance of food and a lower risk of predation. For sea turtles who are endangered, finding an area of lower predation helps to maximize their overall fitness and keep them as an existent species.

Bicoordinate Mapping
Bicoordinate mapping has also been hypothesized as a method of travel for sea turtles along with longitudinal direction. Bicoordinate mapping is defined as a geomagnetic map that depends on both the intensity and inclination of the magnetic field. Changes within the intensity or inclination of the earth's magnetic field can deter a sea turtles direction of travel, so it is important for geographical coordinates to play a role in open-sea migration. It has been shown that when placed into areas with the same latitudinal but different longitudinal coordinates, sea turtles are able to continue traveling in the same magnetic direction they began in. The conclusion is formed that sea turtles may inherit a bicoordinate map to follow that does not coordinate with specific latitudinal or longitudinal points, but helps for the turtle to maintain a constant direction of travel.

Geomagnetic Imprinting
Geomagnetic imprinting is done by the use of inclination angle and field intensity to imprint onto the magnetic fields of the sea turtles natal homes. Imprinting is an innate learning process that is inherited within species to recognize important landmarks and resources. The use of geomagnetic imprinting helps the sea turtles to navigate back in later timelines. This process is not only used in sea turtles, but can also be seen in fish such as Salmo Salar (Atlantic salmon) and Bird migration. This method of navigation is important for female sea turtles, as it has been proven that they will return to their natal beaches to lay their own eggs. Intensity and inclination of the magnetic field depend on latitude, which is helpful in navigating the turtles north or south. This makes it easier for the turtles to follow along the coastline that is most related to their natal beach, ultimately guiding them back. Previous research concluded that returning to the natal beach in order to lay offspring is an advantage towards parasitic resistance and disease, which overall increases the fitness of the turtles.