The effect of the addition of Bacillus probiotic during larvae and postlarvae culture of the white shrimp Litopenaeus vannamei was examined in three separate experiments: (I) Nauplius 4-5 to Zoea 3 , which were exposed to probiotic in the water (P w ), only in the microalgae (P m ), in the water and microalgae (P wm ) and a control with no probiotic (C); (II) Mysis 1 to Mysis 3 , which were exposed to probiotic in the water (P w ), only in Artemia (P a ), in the water and Artemia (P wa ) and a control (C); (III) PL 1 to PL 10 , which were exposed to similar treatments for mysis experiment. The use of probiotic Bacillus spp. resulted in an increase in the survival and growth of zoea and mysis phases, especially when the probiotic was added only in the water. For postlarvae, the use of the probiotic had no influence on the zootechnical parameters, however, there was a reduction in the count of presumptive Vibrio both for water and shrimp.

ABSTRACT. The present study aimed to investigate the reproductive cycle and size at first maturity of Penaeus schmitti through a macro and microscopic approach. Between August 2011 and July 2012, 1169 specimens were collected by an artisanal fishing vessel operating a double trawl off the coast of Pernambuco, northeast Brazil. The total proportion of males (42%) was significantly lower than females (58%), corresponding to the sex ratio of 1:1.38. The total body length at first ovarian maturation (TL50) in females was estimated at 14.2 cm. The ovarian development was divided into four distinct stages based on histological characteristics and visual observations. This is the first reported occurrence of vitellogenic oocytes in the spent stage of P. schmitti, indicating a rapid ovarian maturation after spawning. Furthermore, the frequency of maturation stages, diameter of oocytes and gonadosomatic index were distributed homogeneously throughout the study period, reinforce a continuous reproductive cycle for P. schmitti population in northeastern Brazil.

This study focused on the reproductive dynamics of southern pink shrimp Farfantepenaeus subtilis populations off the coast of Pernambuco, northeastern Brazil. F. subtilis specimens were collected each month between August 2011 and July 2012 by an artisanal fishing vessel. A total of 1246 specimens were collected, of which the majority (56%) were females, and which were significantly larger than the males. Ovary maturation, based on histological and visual criteria, was classified into 4 stages -I: immature, II: maturing, III: mature, and IV: spent. Mature gonads were found in the females throughout the year, but at a higher proportion during the warmer months (October−March). A higher proportion of juveniles were observed between December and April. The mean total body length at first gonadal maturation in female pink shrimp was estimated to be 11.9 cm. These findings could be used to help guide the development of fishery management policies for F. subtilis in the region.

This study describes the structure, growth, mortality and stock status of Litopenaeus schmitti in north-eastern Brazil. A total of 1169 specimens were captured (491 males and 678 females) from August 2011 to July 2012. Specimens were weighed and the length of carapace (CL) and total length were measured. The biometric relationships were estimated through regression analysis and growth was described through the von Bertalanffy model. Additionally, total mortality (Z), natural mortality (M), fishing mortality (F), length at first capture (Lc), maximum yield per recruit (ERMY) and longevity were determined. Females were larger (3.07 ± 0.51 cm) than males (2.68 ± 0.25 cm) and dominant in the largest CL classes. The biometric relationships for males, females and both sexes grouped showed a negative allometric growth. Females showed larger L∞ (asymptotic length) and k (coefficient of growth) (L∞ of 5.00–5.16 cm and k of 1.20–1.26 year−1) when compared with males (L∞ of 4.25–4.30 cm and k of 1.00–1.02 year−1). In general, the mortality of males (Z = 1.93–5.48 year−1; M = 1.59–1.61 year−1 F = 0.32–0.3.89 year−1) and longevity (1.11–2.16 years) were higher than those estimated for females (Z = 1.84–3.76 year−1; M = 1.70–1.77 year−1; F = 0.07–1.99 year−1; 1.07–1.78 years). Results indicated that L. schmitti stock is relatively close to the state of full exploitation. Moreover, the CL of first capture of females (2.44–2.51 cm) is below the length of first sexual maturation of the species. The lack of legislation governing shrimp fishing in the area makes this stock even more vulnerable.