Production yields of the marine shrimp, Litopenaeus vannamei, cultured in earthen ponds in the Gulf of Nicoya, Costa Rica were studied to evaluate the effect of diseases diagnosed during El Niño 2015 event. Two culture systems on earthen ponds were used: three short cycles (SC) per year in farms with low disease incidence and two long cycles (LC) per year in highly affected farms with high mortality. Survival was low in the 2 CL (35.3 ± 3.2%) as compared to the 3 CC (63.1 ± 3.2%). An inverse relationship between average weight at harvesting and the final culture density was obtained (20.3 ± 0.8 g in 2 CL and 15.2 ± 1.6 g in 3 CC) as well as a growth compensation (1.29 ± 0.12 and 1.08 ± 0.10 g/week in 2 CL and 3 CC, respectively). The final production was directly proportional to the survival, with an average of 717 ± 8 kg/ha in 2 CL and 941 ± 53 kg/ha in 3 CC. The production was...

Production yields of the marine shrimp, Litopenaeus vannamei, cultured in earthen ponds in the Gulf of Nicoya, Costa Rica were studied to evaluate the effect of diseases diagnosed during El Niño 2015 event. Two culture systems on earthen ponds were used: three short cycles (SC) per year in farms with low disease incidence and two long cycles (LC) per year in highly affected farms with high mortality. Survival was low in the 2 CL (35.3 ± 3.2%) as compared to the 3 CC (63.1 ± 3.2%). An inverse relationship between average weight at harvesting and the final culture density was obtained (20.3 ± 0.8 g in 2 CL and 15.2 ± 1.6 g in 3 CC) as well as a growth compensation (1.29 ± 0.12 and 1.08 ± 0.10 g/week in 2 CL and 3 CC, respectively). The final production was directly proportional to the survival, with an average of 717 ± 8 kg/ha in 2 CL and 941 ± 53 kg/ha in 3 CC. The production was...

The purpose of this study was to investigate the effect of tray type (plastic and saran) on biometric parameters and oyster growth using four mesh sizes with oysters of different sizes. A total of 5600 juvenile oysters from a pre-growing phase at the same production site were classified into four size groups: smallest, small, medium, and large, based on shell length and body mass measurements. Oysters were placed in plastic mesh bags with thicknesses appropriate for the treatments (3 mm for the smallest and smallest, 6 mm for medium, and 20 mm for large). Saran bags, traditionally used by oyster farmers in Costa Rica, were used as controls. Four replicates were used per treatment and control. The number of oysters per plastic mesh bag and saran bag was 600, 500, 200, and 100 for the smallest, small, medium, and large oysters, respectively. The study lasted 103 days. The lowest survival r...

Se presentan los hallazgos obtenidos de una serie de análisis realizados para un laboratorio de maduración de langostinos de agua dulce de Macrobrachium rosenbergii en Costa Rica. En este centro de producción larval se presentaron abortos recurrentes de hembras grávidas, así como gran mortalidad en los estadios de larvas y pos-larvas. Los resultados indican que incrementos en la presencia de materia orgánica en el agua de los tanques causaron altas prevalencias de ectoparásitos en las masas ovígeras, así como elevados conteos bacteriales en la columna de agua. Esta condición generó cuadros de bacteriosis y parasitosis en las larvas con severas reducciones en la producción.

The incidence of bacterial infections in shrimp hepatopancreas cultivated in the Gulf of Nicoya, Costa Rica, presented a high impact on yields in 2016-2017, affecting the survival of the animals and shrimp farm production. In addition, important incidences of Baculovirus penaei, detected in post-larvae used in part of the shrimp ponds, were reported. An Odds Ratio analysis was performed in an observational case-control study to determine the possible participation of this virus as a risk factor for subsequent bacterioses. The study demonstrates the active participation of Baculovirus penaei as an important risk factor. Survival data are presented by ponds infected by the virus vs free ponds.

This paper presents the findings obtained from a series of analyzes carried out for a freshwater prawn maturation of Macrobrachium rosenbergii in Costa Rica. A large larval production centre had recurrent abortions of gravid females, as well as high mortality in larval and post-larval stages. The results indicate that increases in the presence of organic matter in the water of the tanks caused high prevalence of ectoparasites in the ovigerous masses, as well as high bacterial counts in the water column. This condition generated bacterial and parasitic infections in larvae with severe reduction in production.

The incidence of bacterial infections in shrimp hepatopancreas cultivated in the Gulf of Nicoya, Costa Rica, presented a high impact on yields in 2016-2017, affecting the survival of the animals and shrimp farm production. In addition, important incidences of Baculovirus penaei, detected in post-larvae used in part of the shrimp ponds, were reported. An Odds Ratio analysis was performed in an observational case-control study to determine the possible participation of this virus as a risk factor for subsequent bacterioses. The study demonstrates the active participation of Baculovirus penaei as an important risk factor. Survival data are presented by ponds infected by the virus vs free ponds.

The determination of the degree of gregarine parasitosis in marine shrimp is performed using qualitative or semiquantitative methods, which are based on the observation of visual fields of prepared coprological samples. These methods are subjective and lack repeatability, so tests were conducted using an alternative method based on the review of the total amount of the sample processed, expressing the results as the content of parasitic agents per unit of intestine length analysed. The proposed method is simple and allows for the reduction of the randomness of the counts, which can be useful in cases where greater certainty of diagnostic results is required.