<p>Diamondback Terrapin Nesting Ecology Activity Egg, hatchling and juvenile survivorship Activity developed through the Marine Academy of Technology and Environmental Science in Manahawkin. New Jersey. Produced through students in “Project Terrapin” with the generous support of the following supporters. Terrapin Egg and Juvenile Survivorship Activity 1 Diamondback Terrapin Egg and Juvenile Survivorship Activity Introduction for the Educator (100 egg activity) Diamondback terrapins are turtles that inhabit estuaries along the east and Gulf coasts of the United States. They range from Cape Cod, Massachusetts to northern Mexico. Terrapins were harvested in the late 1800’s through the early 1900’s as a food source with a high demand leading to reductions in their populations across their range. In the 1930’s, terrapins became less desirable food sources and populations increased in areas with good habitat, but not much is known about populations in certain areas. What make terrapins so interesting are their markings, which are highly variable and prominent. Reasons for the variation include genetic diversity and some variations in their patterns could be linked to environmental conditions. Female terrapins grow larger than males and some females could be as large as 23 cm (9 inches) in carapace length. Males are smaller and may reach sizes of 15 – 18 cm (6 or 7 inches) as adults. In terms of maturation, females in New Jersey can mature in 7 – 9 years, while males can mature in 3 – 5 years. Females will nest on bay beach areas adjacent to marshes where they can deposit up to 18 eggs (called a clutch of eggs). The mean clutch size at Sedge Island, Barnegat Bay, New Jersey is around 12 eggs (Wnek, 2006 and 2007). The nesting female terrapin will dig a nest, deposit eggs and immediately return to the water. The depth of the nest depends on the compaction of soil and depth at which the female can dig. Eggs are deposited as deep as 21 cm (9 inches). Temperature of the nest influences the gender of terrapins; Eggs incubated at temperatures above 28 Celsius will mostly develop as female and below this temperature, male. Eggs are somewhat soft, considered cleidoic, which allows for gas exchange during incubation. After approximately two months, terrapins emerge from their nest and make their way to vegetation and nearby marshes. From this point, little is known about their growth and life stage, but we know they live and feed within marsh habitats. Some of their food resources include snails, shrimp, crabs, and fish to name a few. The goal of this activity is to learn about the basic life history characteristics of the diamondback terrapin. You will be assigned a specific egg number. Although there may be 4 – 18 eggs in a nest, we have an activity for 50 and 100 eggs that would be from multiple nests on the North Sedge Island, Barnegat Bay, New Jersey. The goal is to successfully hatch, emerge from the nest, and become an adult terrapin. Gender will not be addressed at this point. A PowerPoint addressing the life history, biology, research and conservation of this species is available for additional information. Also, please see the terrapin reference list for additional information. Here we go… Terrapin Egg and Juvenile Survivorship Activity 2 Items recommended for the activity: You can use 100 ping pong balls or plastic practice golf balls and number them from 1 to 100 using a permanent marker. These represent the egg numbers and types Depending on the number students in the class they could be divided in groups. For example, with a class of 32 students, there can be 8 groups of 4 students. Each of the students in the group would get 3 numbered eggs at random. The group of 4 students with a total of 12 eggs would represent an entire clutch of eggs. The remaining eggs can be distributed at random to individuals in different groups so that some of the groups have 13 eggs total and four individuals have 4 eggs. At the end of the activity, the surviving individual within the clutch is the one remaining! If you cannot get plastic balls to simulate eggs then number pieces of paper. Remember, there are typically 9 – 16 eggs at Sedge Island, Barnegat Bay, New Jersey. You can divide the groups up accordingly to meet the requirements of the clutch and class sizes. References for the classroom: www.dtwg.org (an organization of terrapin biologists, conservationists and educators) www.wetlandsinstitute.org (a leader in terrapin conservation, research and education) www.terrapininstitute.org (a non-profit in Maryland dedicated to terrapin conservation) Diamonds in the Marsh: A Natural History of the Diamondback Terrapin by Barbara Brennessel, 2006. University Press of New England, New Hampshire, ISBN: 13:978-1-58465-536-7 A Day in the Salt Marsh by Kevin Kurtz. Sylvan Dell Publishers, ISBN: 978-0-9777423-1-8 (appropriate for children 3 – 7 years of age). Marine Academy of Technology and Environmental Science “Project Terrapin” at www.ocvts.org (Lessons and basic presentations for all grade levels) http://www.pwrc.usgs.gov/bioeco/terrapin.htm (US Geological Survey Information) http://www.scaquarium.org (South Carolina Aquarium: Lessons for elementary school students) http://www.aqua.org/animals_diamondbackterrapin.html (National Aquarium in Baltimore, Maryland) Research experiences for educators: http://www.earthwatchexpeditions.org/US/exped/avery.html (EarthWatch expedition for educators at Barnegat Bay, New Jersey Terrapin Egg and Juvenile Survivorship Activity 3 Stage one. Eggs dug in a nest in late June with a 60 day incubation period overall. There is a 60% survivorship based on research at Sedge Island, Barnegat Bay, New Jersey. Here is the first 30 days… Egg # Factors contributing to failed egg development 4 Rainstorm flooding the nest 8 Rainstorm flooding the nest 9 Soil compaction preventing gas exchange 13 Soil compaction preventing gas exchange 16 Eaten by egret 23 Eaten by crow 33 Eaten by crow 35 Eaten by raccoon 42 Eaten by raccoon 50 Eaten by mink 51 Eaten by mink 54 Eaten by mink 60 Eaten by mink 65 Dessication 69 Dessication 71 Eaten by mink 77 Eaten by mink 83 Inadvertently dug up 90 Eaten by a crow 92 Eaten by a crow Stage two. Congratulations! Eggs continue to incubate in late July with a 60 day incubation period overall. There is an overall 60% survivorship of embryos. Egg # Factors contributing to death 5 Dessication 6 Eaten by red fox 14 Eaten by red fox 20 Eaten by crow 26 Soil too compacted; improper gas exchange 28 Eaten by raccoon 34 Dug up by a mink and eaten 36 Too low in the nest and waterlogged at high tide 46 Accidentally dug up by caretaker putting up a fence 47 Overcrowded nest with lack of oxygen 53 Overcrowded nest with lack of oxygen 57 Dug up by a mink and eaten 62 Dug up by a mink and eaten 64 Dug up by a mink and eaten 70 Inadvertently dug up 74 Ants got into the egg 76 Flood inundated nest with water Terrapin Egg and Juvenile Survivorship Activity 4 79 Flood inundated nest with water 88 Roots penetrated the egg 97 Roots penetrated the egg Emergence. The terrapins have developed well and two months later, in mid-August are emerging from the nest, making your way to the salt marsh. Congratulations! You have emerged, but… Hatchling # Factors contributing to death 1 Eaten by a Herring gull 15 Eaten by a crow 22 Eaten by a red fox 24 Accidentally stepped on by a person walking on the Island 32 Exhaustion 37 Bit by a fiddler crab 40 Starvation 56 Starvation 59 Accidentally hit by lawn mower on Island 68 Eaten by egret 73 Eaten by a Herring gull 75 Eaten by a Herring gull 81 Cold stunned in late fall 86 Cold stunned in late fall 93 Cold stunned in late fall Juvenile Stage. You are living in the marsh and growing during your first years of development. There are many obstacles and challenges ahead. Hatchling # Factors contributing to death 7 Made way to low marsh ditch and eaten by blue crab 11 Eaten by an Osprey 17 Didn’t survive your first winter 18 Eaten by a red fox that came to the marsh during low tide 19 Caught in a commercial-style crab pot and drowned 21 Boat propeller cut you 25 Ventured to the next marsh and current took you.... exhaustion 29 Went off marsh to swim in shallow water – Striped Bass ate you 38 Exhaustion 41 Eaten by an Osprey 44 Eaten by a River Otter 52 Eaten by a River Otter 58 Crossed from one marsh into another, across the roadway & a car hit you 61 Eaten by red fox at marsh edge 72 Eaten by red fox at marsh edge 80 Caught in strong current and taken out to the ocean during outgoing tide 84 Caught in a commercial-style crab pot Terrapin Egg and Juvenile Survivorship Activity 5 85 Caught in commercial-style crab pot 89 Illegally taken by someone who saw you basking and sold you 96 Big storm tide in winter disrupted your hibernation and you died 99 Big storm tide in winter disrupted your hibernation and you died 100 Disease Sub-adult Stage. You are living in the marsh creeks and water bodies in the estuary growing to adulthood. Juvenile # Factors contributing to death or removal from the system 2 Too curious… drowned in a commercial-style crab pot 3 Eaten by a red fox 10 Got too close to a motor boat and its propeller 12 Ended up in a market as a food source 31 Storm caused you to emerge during winter and you froze 39 Fought with a blue crab and lost 43 Small enough to be eaten by an Osprey 45 Too much time in a commercial-style crab pot 49 Disease 55 Disease 66 Got too close to motor boat and its propeller 67 Big storm disrupted your hibernation and you froze 78 Got too close to the high marsh and a red fox grabbed you 82 Drowned in a commercial-style crab pot 87 Drowned in a commercial-style crab pot 95 Caught under a pier and you couldn’t get out 98 In commercial-style crab pot with numerous blue crabs – they won Adult Stage. You almost made it to the adult stage. Congratulations! You are approximately 5 – 7 years old. Adult # Factors contributing to death 30 Made landfall at Island Beach and didn’t make it across the roadway 48 Drowned in a commercial-style crab pot 91 Drowned in a commercial-style crab pot 94 Too close to a motor boat and you were hit by the propeller Congratulations to Adults #27 and #63! You have made it. In actuality you haven’t, because if you are nesting females, it will be approximately 7 years to nest. Based on becoming a reproductive female adult…. #63 you tried to go into a commercial-style crab pot and couldn’t access it because it had a “bycatch reduction device” (terrapin excluder) and #27 you crossed the roadway to nest at High Bar Harbor on Long Beach Island and were hit. Therefore, #63 – Congratulations! </p>