Analysis of the population structure of deep-hake , Urophycis mystacea Ribeiro, 1903 ( Teleostei: Phycidae ) from the Southeastern Brazil. Morphology and relationship between stable isotopes of sagitta otoliths

Author(s)

Cesar Santificetur Romero

• Document type: Master's Dissertation
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Instituto Oceanográfico (IO/DIDC)
• Defense date: 2013-10-15

Examining board members

Carmen Lucia Del Bianco Rossi Wongtschowski; Wellington Silva Fernandez

• Advisor: Carmen Lucia Del Bianco Rossi Wongtschowski

Abstract

Studies on the population analysis of the deep-hake, Urophycis mystacea, an important tool for stock management, had never been made. In the present study, by analyzing the distribution of lengths in specimens collected over the area, qualitative and quantitative analysis of morphological and morphometric characteristics of otolith sagittae and analysis of isotopic ratios of stable isotopes of these structures, evaluated the homogeneity of the stock, which is an important fishery resource in the southeast-south Brazil.For the analyzes, the south-east coast was divided into three regions. Morphological analyzes were made following the methodology Tuset et. al (2008) and ASSIS (2002), using fifteen features of the otoliths sagittae a chi-square test was used to verify the homogeneity of the distribution of characters along the ontogeny. The morphometric analyzes were performed under a stereomicroscope with fish otoliths belonging to the range between 300 and 499 mm in total length. Morphometric variables were obtained as well as morphometric relationships and shape indicators. Statistical tests were applied on the characters pre-established to check for differences between the regions. Isotopic analysis were done for ten otoliths by region, whose total lengths of fish were between 300 and 499 mm. Five otoliths were taken for analysis of the core and five for the analysis of the whole otolith obtaing the oxygen isotope ratio of 18 oxigen and 13 carbon in a mass spectrometer.The results indicated that there was no morphological variation on the otoliths of the three regions; however the morphometric analysis showed strong seasonal variation and the presence of two \"morphotypes\" otoliths in the region. Tests with stable isotopes suggest that fish born in different places and mix throughout their life. (AU)

• FAPESP's process: 11/14571-4 - Analysis of population structure of depth-codling, Urophycis mystacea Miranda Ribeiro 1903 (Teleostei: Phycidae)from south-southeastern of Brazil. morphology and relationship between stable isotopes of sagittae otoliths sagittae
• Grantee: César Santificetur Romero
• Support Opportunities: Scholarships in Brazil - Master