Browsing by Subject "Marine turtles"

Now showing 1 - 2 of 2
  • Thumbnail Image
    ItemOpen Access
    Critical information gaps remain in understanding impacts of industrial seismic surveys on marine vertebrates
    (Endangered Species Research, 2019-01-01) Elliott, BW; Read, AJ; Godley, BJ; Nelms, SE; Nowacek, DP
    © The authors 2019. Anthropogenic noise is increasing throughout the world's oceans. One major contributor is industrial seismic surveys-a process typically undertaken to locate and estimate the quantity of oil and gas deposits beneath the seafloor-which, in recent years, has increased in magnitude and scope in some regions. Regulators permit this activity despite widespread uncertainties regarding the potential ecological impacts of seismic surveys and gaps in baseline information on some key species of conservation concern. Research to date suggests that impacts vary, from displacement to direct mortality, but these effects remain poorly understood for most species. Here, we summarize potential effects of seismic surveys, describe key knowledge gaps, and recommend broad-scale research priorities for 3 impacted taxonomic groups: fish, marine mammals, and sea turtles. We also suggest further technological advances, improved mitigation measures, and better policy and management structures to minimize the ecological impacts of seismic surveys in light of scientific uncertainty.
  • Thumbnail Image
    ItemOpen Access
    Recent advances on the estimation of the thermal reaction norm for sex ratios.
    (PeerJ, 2020-01) Abreu-Grobois, F Alberto; Morales-Mérida, B Alejandra; Hart, Catherine E; Guillon, Jean-Michel; Godfrey, Matthew H; Navarro, Erik; Girondot, Marc
    Temperature-dependent sex determination, or TSD, is a widespread phenomenon in reptiles. The shape of the relationship between constant incubation temperature and sex ratio defines the TSD pattern. The TSD pattern is considered a life-history parameter important for conservation because the wider the range of temperatures producing both sexes, the more resilient the species is to climate change impacts. We review the different published equations and methodologies that have been used to model TSD patterns. We describe a new flexible model that allows for an asymmetrical pattern around the pivotal temperature, which is the constant temperature producing both sexes in equal proportions. We show that Metropolis-Hastings with Markov chain produced by a Monte Carlo process has many advantages compared to maximum likelihood and is preferred. Finally, we apply the models to results from incubation experiments using eggs from the marine turtle Lepidochelys olivacea originating in Northeast Indian, East Pacific, and West Atlantic Regional Management Units (RMUs) and find large differences in pivotal temperatures but not in transitional ranges of temperatures.