scholarly journals The Influence of Season on the Gonad Index and Biochemical Composition of the Sea UrchinParacentrotus lividusfrom the Golf of Tunis

2012 ◽  
Vol 2012 ◽  
pp. 1-8 ◽  
Author(s):  
Soumaya Arafa ◽  
Moncef Chouaibi ◽  
Saloua Sadok ◽  
Amor El Abed

Seasonal variation in the gonad weight and biochemical composition of the sea urchinParacentrotus lividusfrom the Golf of Tunis (Tunisia) were studied between September 2003 and August 2004. The highest gonad indices occurred in March (16.71%). The spawning period occurred between April and July and resulted in a fall in gonad indices to low level (7.12 ± 0.12%). Protein constituted the main component of the gonad, and lipid and carbohydrate were found at appreciable amounts. Consistent with the gonad cycle, sea urchin biochemical components showed clear seasonal variation with a significant decrease during the spawning period. The polyunsaturated fatty acid (PUFA) group was found at high level (40% of the total fatty acids). Of the PUFA group, eicosapentaenoic (C20:5n−3) and eicosatetraenoic (C20:4n−3) were the most abundant gonadal lipids. The level of PUFA was significantly affected by temperature variation showing an increase during the cold months and a decrease in the hot months.

Author(s):  
M.F. Montero-Torreiro ◽  
P. Garcia-Martinez

Seasonal variations in the gonad index and the biochemical composition of gonad and gut tissue of the sea urchin, Paracentrotus lividus (Echinodermata: Echinoidea) were determined. Samples were collected from Lorbé (Galicia, north-western Spain) between November 1994 and October 1995. The gametogenic cycle of the sea urchin was annual, with a long, single spawning period from May to August 1995. Most of the biochemical components in gonad showed clear seasonal variation, which was related to the gonad cycle. The main component was protein, which ranged between 36 and 60% of the dry weight, with maximum levels coinciding with the minimum levels of glycogen. Gonad glycogen therefore seemed to be the energy source employed for protein synthesis during gametogenesis. Seasonal variation in total lipids in the gonad was less evident; the main lipidic component was triacylglycerol (around 10% of the dry weight), whereas total cholesterol accounted for less than 1%. The gut does not seem to act as a storage tissue in P. lividus and seasonal variation in biochemical components may be a consequence of fluctuations in the availability of food.


Author(s):  
Mourad Guettaf ◽  
Gustavo A. San Martin ◽  
Patrice Francour

The spawning of Paracentrotus lividus has been determined on the basis of the annual gonad index cycle at three sites in the Algiers area presenting low, intermediate and strong hydrodynamism. Three biotopes (Posidonia oceanica beds, rocky substrate with photophilous algae and overgrazed rocky substrate) and two depths (1–3 m and 6–10 m) were considered at these sites, the sex-ratio was always strongly in favour of females (2:1 to 3:1). In all sites but one, there were marked differences in the gonad index and the spawning period between sites; the gonad index reached its maximum value at the site with the weakest hydrodynamism, and the minimum value at the site with the strongest hydrodynamism. Spawning took place in April–May and August–September at the site with the weakest hydrodynamism, in April–June and October–December at the site with intermediate hydrodynamism and only in winter at the site with maximum hydrodynamism. The coexistence, on regional scale, of these reproductive cycles might enable Paracentrotus lividus to compensate the mortality during planktonic larval phase by the fact that spawning of this sea urchin occurred in all seasons.


2014 ◽  
Vol 15 (3) ◽  
pp. 475 ◽  
Author(s):  
S. GARCIA-SANZ ◽  
P. G. NAVARRO ◽  
F. TUYA

Despite sea-urchins can play an important role affecting the community structure of subtidal bottoms, factors controlling the dynamics of sea-urchin populations are still poorly understood. We assessed the seasonal variation in recruitment of three sea-urchin species (Diadema africanum, Paracentrotus lividus and Arbacia lixula) at Gran Canaria Island (eastern Atlantic) via monthly deployment of artificial collectors throughout an entire annual cycle on each of four adjacent habitat patches (seagrasses, sandy patches, ‘urchin-grazed’ barrens and macroalgal-dominated beds) within a shallow coastal landscape. Paracentrotus lividus and A. lixula had exclusively one main recruitment peak in late winter-spring. Diadema africanum recruitment was also seasonal, but recruits appeared in late summer-autumn, particularly on ‘urchin-grazed’ barrens with large abundances of adult conspecifics. In conclusion, this study has demonstrated non-overlapping seasonal recruitment patterns of the less abundant species (P. lividus and A. lixula) with the most conspicuous species (D. africanum) in the study area.


Zoosymposia ◽  
2012 ◽  
Vol 7 (1) ◽  
pp. 247-254 ◽  
Author(s):  
SILVIA MERCURIO ◽  
MICHELA SUGNI ◽  
DENISE FERNANDES ◽  
CINTA PORTE ◽  
MARIA DANIELA CANDIA CARNEVALI

Despite the extensive use of sea urchins in embryology, the hormonal mechanisms regulating echinoid reproductive pro­cesses are scarcely known. This research is focused on the role of estradiol (E2), whose presence and seasonal variations in different echinoderm tissues have been previously reported. Three different concentrations of E2 were administered (via peristomial injection, 2/week) to adult specimens of the sea urchin Paracentrotus lividus for 2 and 12 weeks. The lowest concentration was close to physiological values, previously measured in field specimens. Despite the increase of circulating E2 in the coelomic fluids, neither short- nor long-term hormonal treatment induced marked variations in the considered reproductive parameters. The Gonad Index appeared to be more influenced by the feed intake than by E2. Similarly, the maturation stage of the gonads was not markedly affected by E2 injection, although some sex-specific dif­ferences could be observed: treated females never reached the maximum maturation stage compared to controls, although this was observed in males injected with the lowest E2 concentration. Although further research is needed to confirm our observations, according to the present study E2 does not markedly influence echinoid reproduction and, particularly, it does not promote female maturation, as reported for vertebrates and suggested for asteroid echinoderms.


Author(s):  
Abdellatif Bayed ◽  
Françoise Quiniou ◽  
Ali Benrha ◽  
Monique Guillou

The condition of three intertidal Paracentrotus lividus populations, which inhabit an area between Rabat and Casablanca (Morocco) known by its high wave energy and its substantial anthropogenic disturbances were described. The growth rate of the juvenile sea urchins in this intertidal zone was low compared with more sheltered populations. A sharp increase in the gonad index was observed between January and March at the beginning of a period of algal production, and was concomitant with increases in seawater temperature and food consumption rate. This gonad index increase was followed by a single spawning period occurring between March and June, probably triggered by the phytoplankton bloom induced by upwelling conditions. Larval development in all three populations was severely inhibited and could be explained, in part, by high and generalized Cu contamination throughout the region. Specific contamination of particular populations by Pb or Hg was attributed to local industries and the incomplete dispersion of pollutants in spite of the high hydrodynamics along the Moroccan Atlantic coast. One of the three populations studied showed strong indications of abnormal development; the degradation of its condition appeared to be due to the presence of a wadi (temporary river) which can seasonally reduce the salinity, directly affecting the sea urchin physiology and indirectly enhancing the metal toxicity.


Author(s):  
J.M. González-Irusta ◽  
F. Goñi de Cerio ◽  
J.C. Canteras

The main objective of this study was to describe the reproductive cycle of the sea urchin Paracentrotus lividus on the Cantabrian coast (north of Spain), and assess its relationship with environmental factors. To achieve this, samples were taken monthly from three localities during 17 months in two different habitats. At least 15 individuals from each location and habitat were collected during each sampling occasion and used for assessments of gonad index and histological sections. The water temperature and the chlorophyll concentration were also measured. The breeding season of P. lividus in Cantabria started in March and continued until September with one or two main spawning periods per year (depending on year and population), the first one in the beginning of spring and the second one in the summer. The most important differences in the gonad cycle were observed among localities, and the smallest among habitats. Temperature, photoperiod and nutritive stage are important factors controlling the gonad cycle. The beginning of spawning in the Cantabrian populations coincides with the spring phytoplankton bloom and the rise in temperature, which may act as environmental triggers.


Sign in / Sign up

Export Citation Format

Share Document