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Journal Article 1 Mention
Is it really 1 in 1000 sea turtle hatchlings that survive to adulthood?
Graeme C. Hays2026
Jacques-Olivier LaloëTakahiro Shimada
Few Citations
0 citations · Nature and Landscape Conservation
Open Access

TLDR

Most baby sea turtles do not survive to become adults, but the chance is usually between 1 in 400 and 1 in 2000, not always exactly 1 in 1000.

Summary

1 Study Aim

The paper aims to update and clarify the true survival rate of sea turtle hatchlings (newly emerged baby turtles) that make it to adulthood. The authors want to check if the often-quoted figure of 1 in 1000 is accurate, using modern data on how long adult turtles live and how many eggs they lay in their lifetime. Simply put: The study wants to find out how many baby sea turtles actually grow up, using better numbers than before.

2 Study Design

The authors use current data on adult sea turtle survival rates (how likely adults are to live each year), adult lifespan, and the total number of eggs laid by a female turtle over her life. By combining these numbers, they calculate the likely chance that a single hatchling will survive to adulthood. They also consider how these rates might change in different turtle populations and species, depending on local conditions and threats. Simply put: The researchers use up-to-date numbers about turtle lives and egg-laying to work out the real odds for baby turtles growing up.

3 Findings

The study reveals that the survival rate for sea turtle hatchlings to reach adulthood is usually between 1 in 400 and 1 in 2000. This range depends on factors like how long adults live, how often females lay eggs, and local dangers such as fishing or habitat changes. The authors note that the commonly cited 1 in 1000 figure is a reasonable average, but the real number can be higher or lower depending on the turtle population. They recommend measuring key factors in each area to get more accurate survival rates. The method used in this study could also help estimate survival rates for other reptiles and similar animals. Simply put: The chance for a baby sea turtle to become an adult changes by place and species, but it's usually somewhere between 1 in 400 and 1 in 2000.

Abstract

Abstract Offspring survival is a central component in understanding the life-history of species. With sea turtles, estimates of hatchling survival to adulthood can be traced back to theoretical considerations made over 50 years ago and before key parameters needed in the hatchling survival calculation had been quantified. Here, using up-to-date figures for adult survival rates and hence adult longevity and lifetime reproductive output, we show that the survival rate of hatchlings to adulthood will generally lie between 1 in 400 and 1 in 2000. We show that this survival rate probably varies across populations and species in line with variations in adult survival rates, remigration intervals and clutch frequency and will likely be impacted by factors such as local management, resource availability and bycatch pressures. Popular articles that tend to quote this survival rate as 1 in 1000 are broadly comparable with our estimates, although the survival rate likely varies appreciably across populations. We identify the key parameters that need to be measured for this value to be determined accurately for individual populations around the world. This approach of using values for adult reproductive output to estimate offspring survival rates to adulthood likely has broad utility across reptiles and other taxa.

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