Part 1: Results from Physical Survey

From the June 04, 2023 American Horseshoe Crab quadrant based survey, a total of 399 individual specimens were recorded in reference to their spawning location along Money Island. A total of 39 GPS points were gathered from the maps application on the iPhone 12, with some complications involved. Most noticeably, the iPhone GPS lacked pinpoint accuracy that advanced global positioning systems provide. With that, the pinpoint exact locations of the specimens on the beach may vary between 1 and 5 meters. Also, the GPS dropped location did not change between a few quadrant locations, so their specimen numbers were added together for the G.I.S map analysis. The smallest quadrants consisted of 0 recorded specimens (Northern portion of the beach near the wing-wall), while the largest quadrant total was 21 recorded specimens. Collectively, a total of 182 Horseshoe Crab specimens were recorded landward of the detached breakwaters, while 217 specimens were recorded on the adjacent beach south of the coastal structures (please see map below). A T-Test (assuming unequal variances) was conducted, with a generated p-value of 0.922. Stating that there was no significant difference between spawning locations landward the breakwaters and adjacent to them on this survey date. However, the quadrant survey is not an exact count of Horseshoe Crab specimens seen during the survey, as the quadrants were only taken every square meters along the shoreline.

Over the course of time the American Littoral Society was present at Money Island on June 04, 2023 (approximately 9:00 PM - 2:00 AM June 05, 2023), winds were dominate from the Southeast (with some East-Southeast & South-Southeast variability). The average wind speed (from Ship John Shoal Lighthouse, New Jersey) was 20.13 knots, with a maximum speed of 25.27 knots and minimum speed of 13.80 knots. Based on the physical presence during specimen surveying, a significant portion of the spawning Horseshoe Crab were located just South of the breakwater delineation. This may be caused by favorable sediments deposited there (see Results (Sediments) page for that analysis) and due to the lack of westerly winds which could cause difficulties in locomotion (Please see Results of the Study page for winds). The shoreline just south of the structures may also see an increase in specimens due to its location to the Delaware Bay itself, with it being closer in proximity then the beach located behind the breakwater. The large portion of the shoreline South of the breakwaters is also heavily vegetated, which is why there is a significant drop-off in Horseshoe Crab recordings, as the specimens do not spawn in vegetation (organic material/peat) and it can cause locomotion issues (and impingement depending on vegetation density).

Part 2: Results from Population Study

Part 3: Results from Wind Analysis

In 2022, only two of the survey nights had prevailing westerly winds (May 28 & May 31, 2022). Winds were mostly in a West-Southwest direction on May 28, 2022, with maximum wind speeds of 14.97 knots and wind gusts of 16.52 knots. On May 31, 2022, winds were also dominant from the West-Southwest direction. Maximum wind speeds were 9.33 knots, with gusts upwards of 9.91 knots. Upon running a T-test (assuming equal variances), a p-value of 8.62E-05 which displayed a significant difference in HSC spawning preferences on those nights. However, with 273 HSCs recorded landward of the breakwaters and 509 observed on the adjacent beach front during Westerly winds, the 2022 observations showed that the winds did not play a major role in their nesting site selection. 

In 2023, three of the collection dates provided HSC data associated with Westerly Winds (June 05, 06, & 17 2023). On June 05, 2023, winds were domiant in the West-Northwest direction with maximum winds speeds of 7.58 knots (max gusts: 8.55 knots). June 06, 2023 saw winds prevailing from the West, with wind speeds upwards of 11.86 knots (max gusts: 12.83 knots). June 17, 2023 experienced prevailing winds from the Northwest, with maximum wind speeds of 14.58 knots (max gusts: 17.3 knots). A T-test (assuming equal variances) determine no significant differences in HSC populations in relation to there proximity to NJDEP's project delineation. A p-value of 0.413 was obtained for 2023, providing a different outcome than 2022. However, as of two years post project implmentation, there is not enough evidence to suggest that the American Horseshoe Crab population changes their nesting site selection due to prevailing winds.