Traditional research methods are often limited in their ability to capture broad spatial and temporal changes in species distribution that affect global patterns of biodiversity. To provide range-wide demographic data needed to quantify and evaluate changes in habitat use and support ongoing recovery efforts for the endangered West Indian manatee Trichechus manatus, we analyzed data from a formal manatee sighting network that uses citizen-sourced data for the understudied north-central Gulf of Mexico region. Although historically considered to be outside manatees' typical US range, more than 1700 opportunistic, publicly reported manatee sightings and 23 mortalities have been documented in Alabama and Mississippi since the early 1900s. Live manatee sightings have occurred primarily during warmer months in rivers and subembayments. Manatee mortalities have significantly increased since the mid-1980s and have most often been attributed to cold stress, with 2 known mortalities due to vessel strikes in recent years. Sightings of individual manatees were most common, but group sizes of up to 17 were reported, typically in late summer. Decadal-scale trends in opportunistic sighting records demonstrate persistent spatial and temporal patterns of manatee occurrence in the north-central Gulf of Mexico and suggest greater use and importance of the region as seasonal manatee habitat than previously documented. If applied appropriately, citizen-sourced data have the potential to enhance targeted research efforts, significantly contribute to ecological datasets for a number of species, and provide a useful tool to enhance conservation and management.

Partial migration provides a mechanism for species to shift their geographic ranges into new, environmentally favorable regions but has been poorly studied as a means to alleviate effects of climate change. Populations at the edge of their geographic range are ideal to investigate how migratory behaviors may enable range expansion as adjacent areas become more climatically favorable. We determined the contribution of partial migration to the range expansion of West Indian manatees (Trichechus manatus) using GPS data from tagged individuals that migrated between the northern Gulf of Mexico (nGoM) and primary habitat in peninsular Florida. Most of these manatees migrated to the nGoM annually and exhibited high site fidelity among years. Many individuals spent cumulatively more time in the nGoM than in peninsular Florida, indicating the nGoM is a regular part of their geographic range, and they returned to peninsular Florida to meet temperature-related physiological needs for survival. Autumn migrations most frequently terminated at Crystal River, Florida, and manatees that commenced migration late in the season stopped less frequently and had more directed movements. Spring migrations most frequently terminated at Mobile Bay, Alabama, and several manatees quickly and directly migrated from Florida to nGoM stopover sites. Migrations ranged from 10 to 133 days in length, and variation in duration was primarily driven by use of stopover sites and directedness of travel. These data confirm partial migration as an important component of manatee migratory behavior that has already enabled range shifts for manatees on the U.S.A. Gulf of Mexico coast and has potential to facilitate future responses to climate change. As the most common type of migration across the animal kingdom, partial migration may provide a global mechanism for a diverse variety of species to resist the range limiting effects of climate change.

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The federally endangered Alabama red-bellied turtle (ARBT; Pseudemys alabamensis) occurs in an isolated range in southern Alabama and Mississippi. Several distinct nesting populations of ARBT exist within this range. Here we identify eight microsatellite markers to be used for a genetic comparison of members of these populations. Previously isolated microsatellite loci in the related species Pseudemys floridana amplified cleanly from DNA extracted from ARBT tissue samples. Alleles at all eight loci were polymorphic. Alleles ranged in size from 136 to 295 base pairs in length. The total number of alleles at each locus ranged from 2 to 11. Loci showed no evidence of linkage disequilibrium or variation from Hardy-Weinberg equilibrium. Observed and expected heterozygosities ranged from 0.13 to 0.88 and 0.12 to 0.84 respectively. Some variation in alleles was observed among members of different nesting populations suggesting that these eight loci will be an important tool in further assessing population structure of Pseudemys alabamensis.

Research on marine mammal occurrence in ship channels often focuses on large cetaceans in offshore shipping routes, while nearshore research largely addresses small vessel strikes. Marine mammals, such as the West Indian manatee, that reside in or migrate through nearshore areas, have potential to travel through a wide range of channel types, encountering a greater diversity of vessels than previously recognized. We tested the extent and conditions of ship channel use by manatees along the north-central Gulf of Mexico (nGoM) coast by combining data from telemetry-tracked individuals, opportunistic citizen-sourced sightings, and environmental attributes linked to manatee movements. Manatees used both nearshore boat channels (130 and 300 m wide) and open water fairways but used nearshore channels much more frequently, consistent with habitat requirements. Satellite-tracked individuals swam faster and moved more directly in all channel types, indicating use of these channels as migratory and travel corridors. Accordingly, generalized additive models revealed that manatees used channels most often during spring/early summer and fall and at temperatures coincidental with entry to and exit from the nGoM during migration. Manatees also occurred in ship channels when freshwater discharges were low, likely because timing of peak manatee occurrence in the nGoM coincides with seasonally low discharge periods. Expanding shipping activity worldwide is likely to increase interactions between marine mammals and a variety of vessel types, and these effects may be particularly impactful to migratory animals like manatees that use nearshore habitats at the interface of recreational boating and commercial shipping. Linking near-and offshore ship channel use to migration and habitat use will better aid risk-assessment for vessel collision and other shipping related activities for migratory marine species globally.