We studied the reproductive cycle of the sea urchin Arbacia lixula in a subtidal population from northeast Spain over four years using a gonadosomatic index (GSI) and gonad histology. Our results show that the GSI of A. lixula follows a... more
We studied the reproductive cycle of the sea urchin Arbacia lixula in a subtidal population from northeast Spain over four years using a gonadosomatic index (GSI) and gonad histology. Our results show that the GSI of A. lixula follows a seasonal cycle which peaks in May–July and attains its lowest values in October–November every year. The time course of the GSI matched closely the photoperiod cycle. We also found a remarkable inter-annual variability in the maximum value of GSI, which correlated with mean water temperature during the gonad growth period (winter and spring). Gonad histology was also in agreement with a single gametogenic cycle per year in this species. We explored the application of circular statistics to present and analyse gonadal development data, which allowed us to adequately handle the high intra-individual variability detected, with several developmental stages commonly found within the same gonad. The picture that emerged is one of a gametogenic timing driven by photoperiod, while the amount of reproductive output is determined by temperature. This is coherent with the tropical origin of the species and lends support to recent warnings about an increase in the abundance of this species in the Mediterranean as a result of global warming, with associated increased impact potential in sublittoral communities.
FOR CITATIONS: Salem, H.S. (2011). Pollution of Coastal Areas on the Mediterranean Sea: The Gaza Strip As a Case Study – A Real Environmental Threat and a Big Challenge. A paper given at the Working Meeting of the MIRA Project Expert... more
FOR CITATIONS: Salem, H.S. (2011). Pollution of Coastal Areas on the Mediterranean Sea: The Gaza Strip As a Case Study – A Real Environmental Threat and a Big Challenge. A paper given at the Working Meeting of the MIRA Project Expert Group on Decontamination of the Mediterranean (WP7) “Mediterranean Innovation and Research Cooperation Action” (MIRA). Funded by the DG Research of the European Commission MIRA and FP7, Casablanca – Morocco, 27-30 November 2011.
ABSTRACT: Unfortunately we are destroying our planet – Mother Earth – with our own hands. Let us do our best to prevent, or at least, slow down or reduce this anthropogenic (man-made) destruction. This study investigates the anthropogenic pollution sources caused to the Mediterranean Sea, including construction on the coastal areas, duping of solid waste and wastewater in the Sea, etc., and the Gaza Strip in Palestine (Occupied) is taken as a case study.
