Emanuell Felipe Silva

Scanning electron microscopic investigation of the spermatophore and spermatozoa of the shrimp Farfantepenaeus subtilis (Decapoda: Penaeidae)

Scanning electron microscopy was used to describe the structure of the spermatozoon and spermatophore of Farfantepenaeus subtilis. The spermatophore showed characteristics similar to those of members of the subgenus Farfantepenaeus. This included an extensive glandular epithelium and a lack of a wing. The sperm mass, which was distributed at the periphery of the spermatophore, was surrounded by a large amount of acellular material. The spermatozoon has a spherical main body and a well-defined acrosomal region with a single spike, which was bent in some cells. The immotile sperm cells have an average length of 7.1 ± 0.6 μm. Information on sperm location within the spermatophore will assist in the efficient extraction of the sperm mass during dissection.

POPULATION DYNAMICS OF THE PINK SHRIMP FARFANTEPENAEUS SUBTILIS (PÉREZ-FARFANTE, 1967) IN NORTHEASTERN BRAZIL

This study provides information on the population structure, growth, mortality, maximum recruitment yield, and longevity for pink shrimp Farfantepenaeus subtilis (Perez-Farfante, 1967) on the coast of Pernambuco state, northeastern Brazil. A total of 1246 specimens (545 males and 701 females) were monthly collected from August 2011 to July 2012. Mean total length of females was higher (11.42 ± 1.61 cm) than males (10.5 ± 1.62 cm) and dominated in the largest length classes. Estimation of von Bertalanffy growth parameters for total length resulted in L∞ of 19.74 cm and k of 1.06 year −1 for males, while females’ L∞ was 21.64 cm and k was 1.10 year −1 . Mortality of females was higher than males resulting higher value in the exploitation rates. The exploitation rate for maximum recruitment yield was similar between males and females with a value of 0.67, which was above the exploitation rates (0.50-0.64).

Use of Fluorescent Microscopy for Sperm Quality of Penaeids

The present study is the first attempt to evaluate the use of fluorescent microscopy as a tool for determining the sperm qualitity in penaeid shrimp species. The probes propidium iodide and 6-carboxyfluorescein diacetate (CFDA) were used in combination to assess sperm quality of Litopenaeus vannamei captive broodstock and wild stocks of Farfantepenaeus subtilis and Litopenaeus schmitti. L. vannamei showed a significant higher amount of live cells (80.87%) after 93 days in captivity, when compared to animals entering (day 0) the maturation system (61.03%). The percentages of live sperm cells for wild-caught F. subtilis and L. schmitti were above 50% over the 12-month sample period in northeastern Brazil. These results demonstrate that the fluorescent microscopy can be used as a tool to determine the sperm quality in penaeid, allowing the evaluation of male performance in aquaculture systems, as well as to determine their reproductive cycle in fisheries research.

Reproductive cycle of seabob shrimp Xiphopenaeus kroyeri (Crustacea, Penaeidea) from the northeast coast of Brazil

Abstract The reproductive cycle of Xiphopenaeus kroyeri north-eastern Brazil was described to contribute to the sustainable management of this stock in the region. Specimens were collected monthly from August 2011 to July 2012 using a local vessel of the artisanal fleet. A total of 1201 individuals were analyzed (673 females and 528 males) with a mean carapace length (CL) of 1.88 ± 0.16 cm and total length (TL) of 9.00 ± 1.22 cm. The lowest CL and TL of mature females were 1.33 and 6.5 cm, respectively, and all females above 2.44 cm (CL) and 11.5 cm (TL) were mature. Ovarian maturation was classified into four stages: I (immature), II (maturing), III (mature) and IV (spawned). Individuals of all maturational stages were present throughout the year. Considering the macro and microscopic analysis, it was suggested that this species in north-eastern Brazil has a continuous reproductive cycle, with two seasonal peaks, November/December and February (austral spring and summer). A positive correlation between the percentage of mature females and temperature was observed, and a higher percentage was reported in the warmer months of the year. This suggests that the reproductive peaks can be triggered by water temperature variation throughout the year.