Reproductive biology of Atlantoraja cyclophora (Regan 1903) (Elasmobranchii : Rajidae) off southern Brazil

A total of 459 (245 females, 214 males) Atlantoraja cyclophora was captured by bottom trawl off the coast of Rio Grande do Sul between 30 degrees 40'S and 34 degrees 30'S during surveys conducted in winter 2001 and summer/autumn 2002 at depths of 100-300 M. Total length at maturity was 52.8 cm for females and 48.5 cm for males. Symmetry and functional parity of the gonads were observed in both sexes, but there was no significant temporal variation in either sex for any of the reproductive parameters studied. Ovulation and egg-deposition were similarly intensive in both seasons. In adult females, there was an ovarian resting period at an individual level, though it was not synchronized at a population level. Distribution of egg-bearing females was not related to depth or species' range. (c) 2005 International Council for the Exploration of the Sea, Published by Elsevier Ltd. All rights reserved.

Sexual development and reproductive cycle of the Eyespot skate Atlantoraja cyclophora (Regan, 1903) (Chondrichthyes: Rajidae: Arhynchobatinae), in southeastern Brazil

Specimens o/Atlantoraja cyclophora were collected monthly from commercial fishing landings at Guarujá, São Paulo State, Brazil, from March 2005 to April 2006 at depths between 10 and 146 m. Males ranged from 13.3 to 58.5 cm TL (n = 396). Both the smallest mature male and the largest immature male were 47.0 cm long. Males' size-at-50% maturity was calculated to be 46.3 cm. Females ranged from 11.5 to 68.0 cm (n = 401). The smallest mature and the largest immature female were 51.6 and 53.0 cm long respectively. For the females, size-at-50% maturity was calculated to be 53.2 cm. In the males the hepatosomatic andgonadosomatic indices varied between 0.48 (August) and 3.54 (November) and between 0.15 (November) and 1.45 (June) respectively, with no significant variation for the fourteen-month period. In the females the hepatosomatic and gonadosomatic indices varied from 1.55 and 6.30 3.54 (both for April 2006) and from 0.08 (December) to 4.41 (October) respectively, with no significant difference among months. Egg-bearing females were found in all months with proportions varying from 0.03 (March) to 0.67 (April). Both males and females undergo an annual cycle, with slight seasonal variations in reproductive activity and a peak in the proportion of egg bearing females between April and July.

Length-weight relationships, condition and population structure of the genus Atlantoraja (Elasmobranchii, Rajidae, Arhynchobatinae) in Southeastern Brazilian waters, SW Atlantic Ocean

During the present study, 107 specimens of Atlantoraja castelnaui, 188 of A. platana, and 770 of A. cyclophora, were obtained by commercial vessels operating in Southeastern Brazil from March 2005 to April 2006. Males of A. castelnaui ranged from 17.9-111.0 cm and females from 17.4-116.0 cm total length. Males of A. platana ranged from 13.1-70.0 cm and females from 12.5-76.0 cm total length. Males of A. cyclophora ranged from 13.3-58.5 cm and females from 11.5-68.0 cm total length. Length-weight curves were sexually dimorphic in the three species. The analysis of the angular coefficient (b) demonstrated that growth (in weight) in relation to length was allometric (b>3) in males of A. castelnaui and A. platana, while isometric (b = 3) in females of these species. Conversely, growth of A. cyclphora was isometric in males, while in females it was allometric (b>3). The condition factor varied significantly throughout the year only in females of A. castelnaui.

Annelida, Hirudinida, Stibarobdella moorei (Oka, 1910): new distribution and host records.

The present report is the northernmost capture of the piscicolid leech Stibarobdella moorei in the western South Atlantic Ocean. This is also the first time S. moorei is found associated to a batoid fish in the Brazilian coast, the eyespot skate Atlantoraja cyclophora. Stibarobdella moorei was found fixed in the dorsal side of a male eyespot skate, caught by bottom trawl around of the São Paulo coast, southeastern Brazil. A brief description of the morphology of the parasite and a discussion on the taxonomic status of the S. moorei are presented.

Size at maturity of Atlantoraja platana (Gunther, 1880) (Chondrichthyes : Rajidae : Arhynchobatinae) in the south-west Atlantic Ocean

The sexual development of Atlantoraja platana from the south-west Atlantic Ocean was analysed. According to the reproductive variables considered for both sexes, males were found to mature at 620 mm and females at 715 mm total length. (c) 2008 The Authors Journal compilation (c) 2008 The Fisheries Society of the British Isles.

Description of the egg capsule of Atlantoraja castelnaui (Elasmobranchii, Rajidae)

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Descrição da fauna parasitária de raias e tubarões marinhos (Elasmobranchii), fauna acompanhante da pesca comercial no litoral Sul e Sudeste do Brasil

Pós-graduação em Medicina Veterinária - FCAV