Survey data from 1999-2018 which denotes peak spawning occurrences by day and lunar period, proportion of spawning in May (coinciding with shorebird stopovers), average water temperature, index values for female and male crabs per square meter by beach and baywide, the annual sex ratio, and index of abundance per beach.

This dataset has the following 34 columns:

Column Name | API Column Name | Data Type | Description | Sample Values |
---|---|---|---|---|

Year | year | number | Year of survey | 1999 2014 2005 2016 2002 view top 100 |

DE % Female Spawning in May | de_female_spawning_in_may | number | Proportion of females recorded during May of a given survey year on Delaware beaches | 77 47 37 82 36 view top 100 |

NJ % Female Spawning in May | nj_female_spawning_in_may | number | Proportion of females recorded during May of a given survey year on New Jersey Beaches | 78 85 44 68 66 view top 100 |

Avg. Daily Water Temp. in May (°C) | avg_daily_water_temp_in_may_c | number | Average of daily water temperatures recorded at the National Ocean Service station at Lewes, DE (Station Identification Number 8557380) during the month of May in °Celsius | 16 15.2 15.6 14.7 13.7 view top 100 |

Baywide Spawning Activity Lunar Period 1 | baywide_spawning_activity_lunar_period_1 | number | The mean of the total number of female crabs per total area available for the spawning survey on all surveyed beaches. The first moon phase (new or full) in May around which surveying begins - 2 days before, day of, 2 days after. | 0.12 0.92 0.51 0.56 0.83 view top 100 |

Baywide Spawning ActivityLunar Period 2 | baywide_spawning_activitylunar_period_2 | number | The mean of the total number of female crabs per total area available for the spawning survey on all surveyed beaches. The second moon phase (new or full) in May around which surveying occurs - 2 days before, day of, 2 days after. | 0.17 1.34 0.92 1.06 1.85 view top 100 |

Baywide Spawning ActivityLunar Period 3 | baywide_spawning_activitylunar_period_3 | number | The mean of the total number of female crabs per total area available for the spawning survey on all surveyed beaches. The first moon phase (new or full) in June around which surveying occurs - 2 days before, day of, 2 days after. | 0.3 0.43 1.73 1.49 0.65 view top 100 |

Baywide Spawning ActivityLunar Period 4 | baywide_spawning_activitylunar_period_4 | number | The mean of the total number of female crabs per total area available for the spawning survey on all surveyed beaches. The second moon phase (new or full) in June around which surveying occurs - 2 days before, day of, 2 days after (typically the last period of surveying). | 0.48 0.14 0.43 0.51 0.36 view top 100 |

Number of Males per Female | numbermalesperfemale | number | The number of males observed in a given spawning season per female observed during that same season. | 4.2 3.8 4.7 5.2 3.1 view top 100 |

Total Beaches Surveyed | total_beaches_surveyed | number | Number of beaches on which the standardized form of the spawning survey was conducted baywide | 25 23 24 22 17 view top 100 |

Baywide Male Spawning Activity | baywide_male_spawning_activity | number | The mean of the total number of male crabs per total area available for the spawning survey on all surveyed beaches. | 2.89 2.3 2.28 3.39 2.96 view top 100 |

Baywide Male 90% CI Lower Limit | baywide_male_90_ci_lower_limit | number | 90% Confidence Interval - Lower limit of values where there exists a 90% probability of male horseshoe crab spawning activity | 4.11 2.79 2.98 2.55 2.45 view top 100 |

Baywide Male 90% CI Upper Limit | baywide_male_90_ci_upper_limit | number | 90% Confidence Interval - Upper limit of values where there exists a 90% probability of male horseshoe crab spawning activity | 2.95 2.48 4.36 3.44 4.02 view top 100 |

Baywide Male SD | baywide_male_sd | number | Standard Deviation - Statistical variation of Index of Spawning Activity (ISA) values for males | 0.31 0.45 0.24 0.25 0.33 view top 100 |

Baywide Male CV | baywide_male_cv | number | Coefficient of variation - Unitless description of the amount of variation relative to the mean Index of Spawning Activity (ISA), expressed as a percentage for males | 9 4 8 5 13 view top 100 |

Baywide Female Spawning Activity | baywide_female_spawning_activity | number | Index of female horseshoe crab spawning activity - mean number of female crabs per square meter per night for Delaware and New Jersey beaches | 0.8 0.77 0.91 0.56 0.74 view top 100 |

Baywide Female 90% CI Lower Limit | baywide_female_90_ci_lower_limit | number | 90% Confidence Interval - Lower limit of values where there exists a 90% probability of female horseshoe crab spawning activity | 0.62 0.68 0.89 0.74 0.47 view top 100 |

Baywide Female 90% CI Upper Limit | baywide_female_90_ci_upper_limit | number | 90% Confidence Interval - Upper limit of values where there exists a 90% probability of female horseshoe crab spawning activity | 0.91 0.78 0.87 1.11 0.81 view top 100 |

Baywide Female SD | baywide_female_sd | number | Standard Deviation - Statistical variation of Index of Spawning Activity (ISA) values for females | 0.06 0.07 0.03 0.04 0.02 view top 100 |

Baywide Female CV | baywide_female_cv | number | Coefficient of variation - Unitless description of the amount of variation relative to the mean Index of Spawning Activity (ISA), expressed as a percentage for females | 8 7 6 10 4 view top 100 |

DE Beaches Surveyed | de_beaches_surveyed | number | Number of beaches on which the standardized form of the spawning survey was conducted in Delaware | 13 11 12 8 view top 100 |

DE Male Spawning Activity | de_male_spawning_activity | number | The mean of the total number of male crabs per total area available for the spawning survey on all DE surveyed beaches | 3.8 3.78 2.74 3.93 3.52 view top 100 |

DE Male 90% CI Lower Limit | de_male_90_ci_lower_limit | number | 90% Confidence Interval - Lower limit of values where there exists a 90% probability of male horseshoe crab spawning activity in Delaware | 3.81 3.08 2.27 3.64 2.13 view top 100 |

DE Male 90% CI Upper Limit | de_male_90_ci_upper_limit | number | 90% Confidence Interval - Upper limit of values where there exists a 90% probability of female horseshoe crab spawning activity in Delaware | 4.87 3.88 3.59 2.74 3.52 view top 100 |

DE Female Spawning Activity | de_female_spawning_activity | number | The mean of the total number of female crabs per total area available for the spawning survey on all DE surveyed beaches | 0.81 0.76 0.96 0.93 0.53 view top 100 |

DE Female 90% CI Lower Limit | de_female_90_ci_lower_limit | number | 90% Confidence Interval - Lower limit of values where there exists a 90% probability of female horseshoe crab spawning activity in Delaware | 0.63 0.64 0.62 0.67 0.59 view top 100 |

DE Female 90% CI Upper Limit | de_female_90_ci_upper_limit | number | 90% Confidence Interval - Upper limit of values where there exists a 90% probability of female horseshoe crab spawning activity in Delaware | 0.85 1.08 1.45 0.98 1.06 view top 100 |

NJ Beaches Surveyed | nj_beaches_surveyed | number | Number of beaches on which the standardized form of the spawning survey was conducted in New Jersey | 12 11 10 13 9 view top 100 |

NJ Male Spawning Activity | nj_male_spawning_activity | number | The mean of the total number of male crabs per total area available for the spawning survey on all NJ surveyed beaches | 4 5.46 2.98 3.43 2.24 view top 100 |

NJ Male 90% CI Lower Limit | nj_male_90_ci_lower_limit | number | 90% Confidence Interval - Lower limit of values where there exists a 90% probability of male horseshoe crab spawning activity in New Jersey | 1.55 1.24 4.74 2.15 1.93 view top 100 |

NJ Male 90% CI Upper Limit | nj_male_90_ci_upper_limit | number | 90% Confidence Interval - Upper limit of values where there exists a 90% probability of male horseshoe crab spawning activity in New Jersey | 3.57 2.69 3.59 4.97 4.33 view top 100 |

NJ Female Spawning Activity | nj_female_spawning_activity | number | The mean of the total number of female crabs per total area available for the spawning survey on all NJ surveyed beaches | 0.8 0.57 0.68 1.17 0.83 view top 100 |

NJ Female 90% CI Lower Limit | nj_female_90_ci_lower_limit | number | 90% Confidence Interval - Lower limit of values where there exists a 90% probability of female horseshoe crab spawning activity in New Jersey | 0.68 0.69 0.48 0.84 0.51 view top 100 |

NJ Female 90% CI Upper Limit | nj_female_90_ci_upper_limit | number | 90% Confidence Interval - Upper limit of values where there exists a 90% probability of female horseshoe crab spawning activity in New Jersey | 0.96 0.8 0.83 0.91 0.99 view top 100 |