The recognition response of Penaeus (Litopenaeus) vannamei against thoracic nerve cord-ganglia transplants from three species of Penaeidae: P. vannamei, P. (Litopenaeus) stylirostris, and Trachypenaeus byrdi, and one species of Palaemonidae: Macrobrachium tenellum, was evaluated. Implanted tissues were removed from recipients at the end of different incubation periods, catalogued based on three gross categories (missing, unmelanized, and melanized), and analyzed by histology. Some intraspecific implants of thoracic ganglia from P. vannamei were missing after a few weeks, without activating a haemocytic response leading to encapsulation. The same condition was observed for thoracic ganglia from P. stylirostris and T. byrdi. Unmelanized tissue sections from P. vannamei, P. stylirostris, and T. byrdi, were commonly recovered; however, most implants had a smaller size than their original length (5-6 mm). Intraspecific transplantation in P. stylirostris also generated a time-related reduction in graft size. Based on our observations, missing implants, small grafts and compacted structure of tissues indicate an absorption mechanism from the host without encapsulation. Histological analysis of unmelanized tissues from Penaeidae reveals that the structure of nerve cords is similar to controls, showing living nerve cord cells surrounded by the neurilemma, and no haemocytic encapsulation at the periphery. Neurosecretory cells were also observed alive, but the structure of ganglia was different from control ganglia. On the other hand, tissues from M. tenellum were all encapsulated, showing distinctive black depositions and the distinctive layers of haemocytes. These findings suggest that neither interspecific nor intraspecific thoracic ganglia transplants within Penaeidae keep their tissue integrity inside P. vannamei. The endocrine implications for inducing ovarian maturation have to be investigated.

Reproduction and growth of the fish Lutjanus guttatus (Pisces: Lutjanidae) in the Gulf of Nicoya, Costa Rica. The fish Lutjanus guttatus is important in the fisheries of Golfo de Nicoya, Costa Rica where they are captured with varied gear mainly by the artisanal fleet. We measured specimens from the commercial catch of 2002-2006. Gonadal state was determined macroscopically and age with otoliths The total length-total weight relationship was y = 0.0236x 2.8153 and total length-eviscerated weight y = 0.0216x 2.8129 . Simplified relationships were y = 0.0173x3 and y = 0.0162x3. There is year-round reproduction with peaks in March (dry season) and September (rainy season). Male-female sexual ratio was 1:1. The age-length key for the gulf shows availability until the 6 years of age. The von Bertalanffy growth curve is L (t) = 65,9 (1-e -0,13(t+2,66) ). Rev. Biol. Trop. 57 (1-2): 125-131. Epub 2009 June 30.

Seasonal variation of proximate composition in three commercially important species in the Gulf of Nicoya, Puntarenas, Costa Rica. Nutritional value of seafood for human consumption is worldwide recognized. Some information have been generated in other countries, nevertheless, there is limited information describing the chemical composition of some fishery important species caught in the Gulf of Nicoya. For this reason, we studied the levels of proximal components of the edible parts (fresh) of three commercially important species. The meat samples of snook Centropomus unionesis, the shrimp Trachypenaeus byrdi and the bivalve Polymesoda radiata, were collected from the Puntarenas local fish market during the fishing season of February 2009 to January 2010. Proximate composition analysis was determined according to AOAC methodology, and evaluated the moisture content, and protein and lipid composition of shellfish meats. The results indicated that the moisture content ranged from 74.6-80.6g/100g for snook 76.9-80.0g/100g for shrimp and 77.9-89.5g/100g for green mussel. After the moisture, the protein was the most abundant chemical fraction (6.8 to 21g/100g) showing the highest values in February for the shrimp and green mussel, and December for snook. The largest fluctuations in the lipid content were found in the snook, ranging from 0.7g/100g to 5.6g/100g; the highest values in this fraction were found in shrimp, green mussel and snook, for July, February and April samples respectively. Considering these results, we concluded that fish and shrimp species studied are a good alternative for human consumption as a source of protein and low lipid content.