Potential Benefits and Shortcomings of Marine Protected Areas for Small Seabirds Revealed Using Miniature Tags

Abstract

Marine protected areas are considered important tools for protecting marine biodiversity, and animal tracking is a key way to determine if boundaries are effectively placed for protection of key marine species, including seabirds. We tracked chick-rearing brown noddies (Anous stolidus) from the Dry Tortugas National Park in Florida USA in 2016 using 1.8 g Nanofix GPS tags (n = 10), making this the first time this species has ever been tracked. We determined movement parameters, such as flight speed, distance traveled and home range, and how birds used a complex of marine protected areas including the Dry Tortugas National Park which is largely no-take (i.e., no fishing or extraction permitted), and the Florida Keys National Marine Sanctuary, of which two Ecological Reserves totaling 517.9 km 2 are no-take. Birds remained largely within marine protected areas, with 91.3% of birds' locations and 58.8% of the birds' total home range occurring within the MPAs, and 79.2% of birds' locations and 18.2% of the birds' total home range within no-take areas. However, areas of probable foraging, indicated by locations where birds had high-residence time, were found within one of the MPAs only 64.7% of the time, and only 6.7% of those locations were in no-take areas. Birds traveled a mean straight line distance from the colony of 37.5 km, primarily using the region to the southwest of the colony where the shelf break and Loop Current occur. High-residence-time locations were found in areas of significantly higher sea surface temperature and closer to the shelf break than low residency locations. A sea surface temperature front occurs near the shelf edge, likely indicative of where Sargassum seaweed is entrained, providing habitat for forage species. Much of this region, however, falls outside the boundaries of the marine protected areas, and brown noddies and other species breeding in the Dry Tortugas may interact with fisheries via resource competition or discard foraging. The complex of marine protected areas in the region encompasses a large portion of the overall habitat for this small seabird species, however a large portion of the key foraging habitat fell outside the boundaries of the marine protected areas. This study highlights areas for potential management changes including the protection of additional areas, and the importance of advanced tracking technology for management of marine species.

Framework for mapping key areas for marine megafauna to inform Marine Spatial Planning: The Falkland Islands case study

“…While basic data quality is included as a weight within the framework, there is scope to add a parallel analysis to produce a simple way of mapping data accuracy and to assess whether tracking data is representative for each species or colony (e.g. nonlinear asymptotic regression analysis, previously used by Lascelles et al 2016, Soanes et al 2013Maxwell et al 2016). This would give managers an easily understood visual way of assessing potential risks associated with their decisions for MSP due to uncertainty from the raw location data fed in the framework (e.g., Johnsen et al 2008).…”

Seasonal spatial segregation in blue sharks (Prionace glauca) by sex and size class in the Northeast Pacific Ocean

“…To visualize the area used seasonally by blue sharks in our study region, kernel density estimations were made for each of the seasons modelled, resulting in four estimations across seasons and size classes as above. We used the kernel density functions in the “adehabitatHR” package, specifically the fixed kernel density (KD) estimation (Calenge, ; Maxwell, Conners, Sisson, & Dawson, ; Silverman, ). Bandwidth was determined using the reference bandwidth (href) for all datasets.…”

Route Fidelity during Marine Megafauna Migration

“…Empirical approaches, such as animal telemetry, can be used to develop and assess data-based models of animal movement, with the strongest models creating opportunities to inform conservation and management decision making with respect to both space and time. At a fundamental level, telemetry studies remain uniquely powerful ways to inform marine conservation through databased demonstrations of when and where marine megafauna are located across vast expanses of open-ocean (Shillinger et al, 2008;Gredzens et al, 2014;Maxwell et al, 2016;Dawson et al, 2017). Technological advances in animal telemetry, combined with advances in remote sensing (e.g., Figures S3-S8), have created unprecedented opportunities to retrospectively extract and analyse the geophysical and oceanographic conditions experienced by individual migrants during long-distance migration.…”