Populations are more effectively managed with information on breeding and dispersal behavior, making the evaluation of these characteristics essential for effective conservation of a species. In the USA, 2 critical habitat units were designated in 2009 for the federally endangered smalltooth sawfish Pristis pectinata. Previous research in the Charlotte Harbor Estuary Unit (CHEU) of critical habitat shows that female smalltooth sawfish are polyandrous and highly philopatric to nursery grounds. However, these characteristics have not yet been examined in a larger area of designated critical habitat: the Ten Thousand Islands/Everglades Unit (TTIEU). We used microsatellite genotypes from 214 juvenile smalltooth sawfish to examine mating and dispersal behavior via sibship analyses and reconstruction of parental genotypes with the program COLONY. Parental reconstruction yielded 71 female and 117 male genotypes. Many females returned to the same region within TTIEU for parturition on a biennial cycle; however, at least 1 female switched parturition sites within TTIEU and at least 2 females produced litters in both TTIEU and CHEU over the study period. The maximum number of pups genetically assigned to 1 female was 12, a number that is consistent with that found for CHEU (8 pups), and within the litter size range reported (7 to 14) for the species. Confirmation of these mating behaviors and reproductive characteristics is important for understanding how the present population uses these protected habitats at different life stages, and for determining future habitat protection and population expansion strategies to restore smalltooth sawfish to previously occupied areas of their range.

The Critically Endangered (International Union for Conservation of Nature) largetooth sawfish, Pristispristis, was historically distributed in the tropical Pacific, Atlantic and Indian Oceans. Today, ‘viable’ populations are largely limited to northern Australia. Populations that have suffered from drastic declines in abundance, such as those experienced by P.pristis, are typically at risk of having reduced, or low, levels of genetic diversity. Previous research found that P.pristis in Australia have experienced a genetic bottleneck, but it is unclear whether this bottleneck is the result of contemporary declines over the last century, or if it is the result of historic processes. A direct way to assess whether this genetic bottleneck occurred relatively recently is to compare levels of genetic diversity in contemporary and historic populations. Sawfish saws that were taken as trophies over the past century can now be found in natural history collections around the world and can provide DNA from past sawfish populations. We collected tissue samples from 150 dried P.pristis saws found in both private and public natural history collections. Because DNA from natural history specimens tends to be highly degraded, we targeted ten small DNA fragments, ~150 base pairs each, to amplify and sequence the entire mitochondrial control region. These data will provide important baseline information about P.pristis that can be used to quantify any loss of genetic diversity over the past ~100 years and assess their long-term survival potential. If the levels of genetic diversity in contemporary populations are severely reduced from those of past populations, protecting remaining genetic diversity within and between viable populations should be a priority in conservation plans.

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