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The effects of substrate temperature on the reproductive success of Caretta caretta on a volcanic beach in the Mediterranean Sea

Vecchioni Luca, Citarrella Andrea, Cambera Irene, Di Gangi Antonella, D’Emanuele Dario, Ventura Lucia, Principato Elena, Visconti Giulia, Torri Marco, Faraone Francesco P., Arculeo Marco

Journal of Water and Land Development

2024

no. 61

30--38

A five-year of monitoring (2018-2022) of the loggerhead sea turtle Caretta caretta nests in “Pozzolana di Ponente” beach on Linosa Island (Pelagie Archipelago, Italy) is here reported. To explore how temperatures affect the hatching success and the possible occurrence of any malformation in hatchlings, incubation temperature values were recorded using data loggers positioned at depths of 5 and 35 cm (for each nest) from the surface, approximately 0.5 m from the nest chamber. The obtained results highlighted important issues related to the success of hatching and the incidence of body anomalies. The temperatures recorded at different depths near the nests (5 and 35 cm) in some periods of incubation of the eggs were above optimal development temperature (i.e., ~33°C), causing high mortality rates, especially during the first two years of the survey (2018-2019). In the next three years (2020-2022), the implementation of shading cover cloths of the nests increased the survival rate and decreased the incidence of malformed individuals. Furthermore, atmospheric temperature data were extrapolated from the “Copernicus Climate Change” web service and included in our analyses to assess any changes over the timeframe analysed. Over five years (2018-2022), the average atmospheric temperature increased slightly by 1.7°C. In light of global warming, the implementation of effective and low-cost mitigation activities, such as the use of shade cloth covers to protect the nests from overheating, should be considered a suitable conservation action.

Reproductive parameters of Caspian Gull Larus cachinnans Pallas, 1811 in different habitats nearby and away fish ponds

Gwiazda R., Neubauer G., Betleja J., Bednarz Ł., Zagalska-Neubauer M.

Polish Journal of Ecology

2015

Vol. 63, nr 1

159--165

Reproductive performance of gulls depends on a variety of factors, but food abundance and its availability are among the most important. Clutch and egg sizes in gulls are found to be strongly influenced by food availability, thus better reproductive performance in the colony with greater fish availability (near fish ponds) was expected in that study. We compared the reproductive traits (clutch size, volume of eggs in the full clutch, relative volume of the C-egg (the third egg in gull’s clutches) and hatching success) of Caspian Gull Larus cachinnans in five inland colonies in Poland located at a gravel pit, a lake, a river and two dam reservoirs. Differences in the clutch size between sites were found, with the lowest at a lake. We found similar clutch volume in all studied colonies. C-eggs were slightly smaller than A- and B- eggs, in all colonies and all study years, but the relative volume of C-egg in colonies located near fish ponds (<10 km) was significantly greater compared to colonies located far away. This may be explained by high fish availability in fishponds in comparison to other habitats. However hatching success (the ratio of the number of hatched chick to the number of eggs laid) was highest in the colony at the lake. This indicates that both inland habitats a gravel pit and a lake offered good food conditions for large gulls when fish ponds are nearby.

The spiny-cheek crayfish Orconectes limosus (Rafinesque, 1817) as an inhabitant of the Baltic Sea - experimental evidences for its invasion of brackish waters

Jaszczołt J., Szaniawska A.

Oceanological and Hydrobiological Studies

2011

Vol. 40, No.3

52-60

The main aim of the present study was to determine the effect of low salinity conditions (3 PSU and 7 PSU) on the hatching success, growth and mortality of Orconectes limosus. The results revealed that berried females survived exposure to salinities of 3 PSU and 7 PSU whilst incubating their eggs. The reproductive success reached 100% at both salinities. The length increment of young crayfish per molt was larger at 7 PSU than at 3 PSU – but their condition was affected by higher salinity. The mortality among juveniles reached approximately 50% within 5 weeks of hatching at both salinities.