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- Ghost crab predation of loggerhead turtle eggs across thermal habitatsPublication . Martins, Rita; Marco, Adolfo; Patino-Martinez, Juan; Yeoman, Kate; Vinagre, Catarina; Patrício, Ana RitaThe reproductive success of sea turtles is highly influenced by the environmental and biological conditions of the nesting beach. Maio Island, Cabo Verde, one of the main nesting sites for the Northeast Atlantic loggerhead subpopulation, displays marked heterogeneity of sand coloration, with dark, mixed and light sandy beaches, resulting in different thermal habitats. Considering that sand temperature can influence both sea turtle embryo development and predatory activity by ghost crabs – the main predators of clutches and hatchlings at Cabo Verde – we surveyed loggerhead nesting beaches at Maio Island, with three sand colorations (‘beach type’), to assess: 1) the density and size of ghost crab burrows, as a proxy for ghost crab density and size, and 2) ghost crab predation on 70 loggerhead nests. We further assessed nest site selection, by considering the number of nesting activities and clutches laid across beach type. There were no evident trends in the distributions of ghost crab density and size between years or beach type. We found that ghost crab predation is a major source of mortality in Maio Island, affecting 67.8% (n = 59) of the nests. Ghost crab predation was variable between beaches, but generally, at the warmer dark sand beaches, clutch mortality was mostly caused by ghost crab predation (53.2%, n = 17), while at the mixed sand beaches mortality by predation was low (7.5%, n = 18), compared to mortality due to other causes (49.9%), indicating that other factors can also significantly impact clutch survival. The mixed sand beaches had more nesting activities and higher nest density (2.29/m2; 1.25/m2, respectively), compared to the light sand (0.72/m2; 0.35/m2) and the dark sand beaches (0.73/m2; 0.27/m2), suggesting a possible predation-free nesting preference. Our findings show that some beaches are in need of nest protection, thus we recommend both in situ nest protection and egg translocation to safe hatcheries, depending on the threats identified, to enhance clutch survival at such heterogeneous nesting areas as Maio Island.
- Differential effects of food restriction and warming in the two-spotted goby: Impaired reproductive performance and stressed offspringPublication . Lopes, Ana F.; Murdoch, Robyn; Cardoso, Sara D.; Madeira, Carolina; Costa, Pedro M.; Félix, Ana Sofia; Oliveira, Rui Filipe; Bandarra, Narcisa; Vinagre, Catarina; Lopes, Ana Rita; Gonçalves, Emanuel J.; M. Faria, AnaClimate change is a growing threat to marine organisms and ecosystems, and it is already modifying ocean properties by, for example, increasing temperature and decreasing pH. Increasing water temperature may also lead to an impairment of primary productivity and an overall depletion of available zooplankton. Understanding how the crossover between warming and zooplankton availability impacts fish populations has paramount implications for conservation and mitigation strategies. Through a cross factorial design to test the effects of ocean temperature and food availability in a temperate marine teleost, Pomatochistus flavescens, we showed that hindered feeding impacted sheltering and avoidance behaviour. Also, low food availability impaired fish reproduction, particularly male reproduction, as the expression of cyp11b1, a gene with a pivotal role in the synthesis of the most important fish androgen, 11-ketotestosterone, was significantly reduced under a low food regime. In contrast, temperature alone did not affect reproductive success, but offspring showed increased saturated fatty acid content (embryos) and increased lipid peroxidation (larvae). Altogether, food availability had a stronger effect on fitness, showing that coping with elevated temperatures, an ability that may be expected in shallow-water fish, can be indirectly impacted, or even overwhelmed, by the effects of ocean warming on primary productivity and downstream ecological processes.