New insights on sea turtle behavior during the ‘lost years’

Several marine turtle species spend their first years of life in oceanic habitats. This early life stage is referred to as the “lost years” due to the difficulty of accessing individuals for study offshore. We satellite tracked 114 wild-caught juvenile turtles (straight carapace lengths 12.3-29.9 cm) from the Gulf of Mexico between 2011-2022 to investigate “lost years” movements with respect to traditional definitions assigned to the life stage. Satellite-tracked turtles included 79 green turtles (Chelonia mydas), 26 Kemp’s ridleys (Lepidochelys kempii), 5 loggerheads (Caretta caretta), and 4 hawksbills (Eretmochelys imbricata). Many tracked turtles transited between oceanic (>200 m depth) and neritic waters (<200 m depth), challenging the assumption that this life stage is exclusively found in oceanic habitats. Turtle movements differed from oceanographic surface drifters, providing further evidence that sea turtles of this life stage do not exclusively drift with currents. We re..., Location data for juvenile sea turtles in the Gulf of Mexico were collected via satellite telemetry. We deployed oceanographic surface drifters with each turtle release against which to compare turtle movements. State space models were run in R. Full methods available in published manuscript. DOI: https://doi.org/10.1098/rspb.2024.2367, , # New insights on sea turtle behaviour during the 'lost years'

[https://doi.org/10.5061/dryad.stqjq2cc2](https://doi.org/10.5061/dryad.stqjq2cc2)

## Description of the data and file structure

### Files and variables

#### File: lost\_years\_SSM.R

**Description:** R script to format telemetry data files and then use the bsam package to estimate positions at a 12-hour timestep and estimate behavioral states.

#### File: turtle\_location\_data\_forSSM.xlsx

**Description:** Excel file with individual sea turtle locations, Argos tag IDs, time/date of location received, and Argos location codes. There are 112 individuals in the dataset, as two tracked turtles were not included in the state space model analysis: one green turtle with an 8-hour tracking duration too short for the 12-hour model timestep, and one green turtle with a 7-day transmission gap that failed to converge.

##### Variables

* Species: Lk= Kemp's ridley, Cc = loggerhead, Cm = green turtle, Ei = hawksbill
* Tag_id: Argo...

多种海龟物种的幼年阶段会在大洋生境中度过。由于难以在远海获取研究个体，这一早期生活阶段被称为“迷失之年”。我们于2011至2022年间，在墨西哥湾对114只野生捕获的幼龟（背甲直线长12.3~29.9厘米）进行卫星追踪，以结合该生活阶段的传统定义，探究“迷失之年”的活动模式。本次追踪的海龟包括79只绿海龟（Chelonia mydas）、26只肯普氏丽龟（Lepidochelys kempii）、5只蠵龟（Caretta caretta）以及4只玳瑁（Eretmochelys imbricata）。
多数追踪个体在大洋生境（水深＞200米）与近岸浅海生境（水深＜200米）间移动，这一结果挑战了“该生活阶段仅栖息于大洋生境”的预设。海龟的活动模式与海洋表层漂流浮标存在差异，进一步证明了该阶段的海龟并非仅随海流被动漂移。[原文此处内容截断] 墨西哥湾幼海龟的位置数据通过卫星遥测技术采集。我们在每只海龟放归时同步部署海洋表层漂流浮标，用于比对海龟的活动模式。状态空间模型通过R语言运行。完整实验方法已发表于相关论文，DOI：https://doi.org/10.1098/rspb.2024.2367。
# 海龟“迷失之年”行为研究新进展
https://doi.org/10.5061/dryad.stqjq2cc2

## 数据与文件结构说明

### 文件与变量

#### 文件：lost_years_SSM.R
**功能说明：** 用于格式化遥测数据文件，并借助bsam包以12小时间隔估算位置、同时辨识行为状态的R脚本。

#### 文件：turtle_location_data_forSSM.xlsx
**功能说明：** 包含单只海龟位置、Argos标签编号、位置接收时间/日期以及Argos位置等级的Excel文件。本数据集共包含112只个体，其中2只追踪个体未纳入状态空间模型分析：1只为追踪时长仅8小时、无法适配12小时间隔模型的绿海龟，另1只为存在7天传输间隙、模型未收敛的绿海龟。

##### 变量说明
* 物种：Lk=肯普氏丽龟，Cc=蠵龟，Cm=绿海龟，Ei=玳瑁
* 标签编号：Argo...