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| Author(s): |
Dalilla da Silva Salvati
Total Authors: 1
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| Document type: | Master's Dissertation |
| Press: | Botucatu. 2017-03-20. |
| Institution: | Universidade Estadual Paulista (Unesp). Instituto de Biociências. Botucatu |
| Defense date: | 2017-02-22 |
| Advisor: | Rogério Caetano da Costa; Sabrina Morilhas Simões |
| Abstract | |
The objective of this study was to analyze abundance, spatio-temporal distribution, abundance relationship with abiotic factors, population structure, juvenile recruitment period, sex ratio, growth, longevity and duration juvenile phase of the juvenile shrimps Farfantepenaeus brasiliensis and F. paulensis along the Estuarine-Lagoon-Complex of Cananeia-Iguape, extreme south of the state of São Paulo. The sampling were carried out monthly between July/2012 to June/2014, in the region of Cananeia. The individuals were captured in seven established sampling stations, being E1 to E4 in the Marine Coastal Area (CA) and E5 to E7 in the Mar Pequeno region (MP). The abiotic factors were recorded at each sampling stations, the temperature and salinity of the bottom water was recorded monthly and the type of sediment and organic matter content per season. The shrimps were identified as to species, sex, measured on carapace length (CL mm) and quantified in each month and sampling station. The juvenil recruitment was characterized by the entry of individuals minors into the population. Growth curves were estimated using the von Bertalanffy growth model and longevity and juvenile phase time were obtained by the inverse von Bertalanffy equation. The general mean of the bottom water temperature was 25.1 ± 3.1°C. The regions presented similar mean, in the Coastal Area the value was 22.7 ± 3.1°C and in the Mar Pequeno 23.7 ± 3.1°C. The salinity of the bottom water had an general mean of 31.3 ± 5.0. The highest averages were recorded in the Coastal Area (34.1 ± 5.0) in relation to the Mar Pequeno (27.7 ± 5.0). The type of sediment was not different between the Mar Pequeno and the Coastal Area, being that, in general, was composed mainly by very fine sand. The organic matter content varied in both regions, oscillating from 0.6 - 12.0% in the Mar Pequeno and 0.8 - 16.6% in the Coastal Area. The station sampling that presented the highest average organic matter content was E4 (6.1 ± 3.2%). Were captured 613 individuals from F. brasiliensis, 407 from the Mar Pequeno and 206 from the Coastal Area. Already F. paulensis was captured 947 individuals, 748 in the Mar Pequeno and 199 in the Coastal Area. The highest abundances of both species occurred in the spring, summer and station sampling E5. Only the temperature was correlated positively with the abundance of both species (RDA, p < 0.05). Although there was no significant relationship, was observed the preference of F. brasiliensis for sediments with a high percentage of silt+clay and, in the case of F. paulensis, for very fine sand. The mean size (CL mm) of F. brasiliensis and F. paulensis were, respectively, in MP 18.8 ± 3.5 and 19.0 ± 3.7 and in CA 19.2 ± 3.6 and 18.9 ± 3.7. The juvenile recruitment was seasonal with the main peak of both species in January/2014. Sex ratio was in favor of females for both species. The parameters growth and longevity (tmax) estimated were: CL∞ = 45.5, k = 1.8 year-1, t0 = -0.27 and tmax = 2.52 years for males and CL∞ = 55.2, k = 1.6 year-1, t0 = -0.85 and tmax = 2.88 years for females of F. brasiliensis. For F. paulensis the values obtained were CL∞ = 40.7, k = 2.3 year-1, t0 = -0.37 and tmax = 2.04 years for males and CL∞ = 56.5, k = 1.9 year-1, t0 = -0.083 and tmax = 2.37 years for females. There was significant difference in the growth curve between males and females, with males having higher k values and females having larger sizes and longevity for both species. The duration of juvenile phase calculated was ≈ 7 months for F. brasiliensis and ≈ 5 months for F. paulensis. We can conclude that Cananeia is a nursery of extreme importance for the establishment and growth of juveniles of F. brasiliensis and F. paulensis. The temperature and the sediment were very relevant factors in the distribution of the species. The peaks of juvenile recruitment of the species is not synchronized with the closing of fishing, so the closing of fishing should be reviewed, can be more effective and result on a more sustainable exploitation. All the estimated growth parameters for the Estuarine-Lagoon-Complex of Cananeia-Iguape were consistent with the life cycle of the species and similar to the studies in the literature. The juveniles can stay in the Mar Pequeno and Coastal Area of Cananeia until their 5 to 7 months of life, before migrating to the oceanic region, where they will complete the life cycle. This time was similar to most of the species of the genus Farfantepenaeus already studied. (AU) | |
| FAPESP's process: | 15/15210-6 - Distribution and population dynamics of juvenile prawns Farfantepenaeus brasiliensis (Latreille, 1817) and F. paulensis (Pérez Farfante, 1967) in the Cananéia region, extreme south of the State of São Paulo |
| Grantee: | Dalilla da Silva Salvati |
| Support Opportunities: | Scholarships in Brazil - Master |