Condición nutricional de la langosta, Panulirus argus (Decapoda: Palinuridae): 60 años de índices extensivos y variación espacio-temporal en Cuba / Nutritional condition of the lobster, Panulirus argus (Decapoda: Palinuridae): 60 years of extensive indices and spatio-temporal variation in Cuba

Resumen Introducción: En el hábitat natural, el estado nutricional insatisfactorio de un número elevado de ejemplares es expresión de la influencia de factores desfavorables. Objetivo: Determinar variaciones espacio-temporales en el estado nutricional de langostas Panulirus argus, relacionarlas con variaciones reportadas en la comunidad bentónica y demostrar, mediante la aplicación de indicadores analíticos y morfométricos, que la variación de factores ambientales afecta a ambos grupos de índices; y que no todos los índices de condición nutricional evidencian por igual el impacto generalizado del proceso de deterioro ambiental en este golfo. Métodos: Las langostas se capturaron en seis áreas de pesca. La condición nutricional se estimó mediante tres índices no destructivos, poco costosos y de fácil y rápida aplicación (extensivos): índice de refracción de la hemolinfa (IRH), relación peso total / largo total = Klt, y factor de condición (FCA). Las variaciones a largo plazo (60 años) se determinaron mediante índices morfométricos (Klt y FCA). Se analizaron datos de los períodos 1963-1964 (N = 29 001), 1983-1993 (N = 3 123) y 2011-2017 (N = 3 600), separándolos en épocas de Lluvia y Seca. Resultados: En todos los períodos la condición nutricional varió significativamente entre áreas, pero sin similitudes entre períodos. Esto indica que los factores que impactan en el estado nutricional tienen una influencia estocástica más característica de factores ambientales. Aunque los tres índices fueron menores en 2017, sólo IRH disminuyó gradualmente entre 2011 y 2017, lo que sugiere que este índice, y los morfométricos, expresan diferente información. Todas las correlaciones fueron estadísticamente significativas, los coeficientes más altos se establecieron entre los índices morfométricos. El peso total y el Klt no mostraron diferencias entre Seca y Lluvia. Sin embargo, IRH y FCA resultaron mayores en Seca, hecho que se constató para cada sexo. FCA y Klt no presentaron diferencias entre el período 1963-1964 y el período 1983-1993, pero aumentaron (P < 0.05) en el período 2011-2017, lo que, dado el carácter morfométrico de estos índices, se atribuye a la presencia de langostas de mayor peso en las áreas de pesca. Conclusiones: Los menores valores en 2017 y la tendencia gradual al decrecimiento de IRH, corroboran el carácter generalizado del deterioro ambiental en el golfo de Batabanó, lo cual no fue igualmente expresado por los tres índices.

Abstract Introduction: Nutritional condition indices are morphophysiological estimators that quantify the nutritional status of organisms. In the natural habitat, unsatisfactory nutritional stage of numerous individuals is an expression of unfavorable factors. Objectives: Determine spatio-temporal variations in the nutritional condition of lobsters Panulirus argus, relate them to variations reported in the benthic community, and to demonstrate, through the application of analytical and morphometric indices, that variations of environmental factors affects both groups of indices due to its potential magnitude and its generalized nature. Methods: Lobsters were captured at six sites. Nutritional condition was estimated by three non-destructive, inexpensive and quick indices also easy to apply, which it means extensive indices: blood refractive index (BRI), relationship between total weight and total length (K), and condition factor (CFA). Because there are no historical records of BRI, long-term variations (60 years) were determined using morphometric indices (Klt and CFA). Data from the periods 1963-1964 (N = 29 001), 1983-1993 (N = 3 123) and 2011-2017 (N = 3 600) were analyzed, separating them in the rainy and dry seasons. Results: In all the periods the nutritional condition varied significantly between sites, but without similarities between periods. Despite this, it increased progressively in three sites. This indicates that factors impacting nutritional condition have a stochastic influence that is constantly changing, which is more characteristic of environmental factors than anthropogenic factors. Although the three indices showed a lower nutritional condition in 2017, only BRI gradually decreased between 2011 (16.6) and 2017 (14.2), which suggests that this index, and the morphometrics (Klt and CFA), express different information. All correlations were statistically significant but greatest coefficients were established between morphometric indices. The total weight and the Klt index did not show differences between rainy and dry seasons. However, BRI and CFA were statistically greater in dry season, a fact that was found for each sex. Both CFA and Klt decreased slightly (P > 0.05) between the first (1963-1964) and the second (1983-1993) period and then increased (P < 0.05) in the current period (2011-2017). Because they both are morphometric indices, this was attributed to the presence of greater weight lobsters. Conclusions: The lowest values in 2017 and gradually decreasing trend in BRI, corroborate the generalized nature of the environmental deterioration in the Gulf of Batabanó, but this was not equally expressed by the three indices.

[Variations of the nutritional condition of lobsters Panulirus argus (Decapoda: Palinuridae) in Eastern region of the Gulf of Batabanó, Cuba]. / Variaciones en la condición nutricional de langostas Panulirus argus (Decapoda: Palinuridae) en la región este del Golfo de Batabanó, Cuba.

Nutritional condition can affect survival and growth rate of crustaceans, and this is mostly affected by habitat conditions. This study describes the space-temporary nutritional changes in this commercially important species. With this aim, the variations in the nutritional condition (K) of lobsters from four zones (1, 2, 4 and 5) in the Gulf of Batabanó, Cuba, were determined. For this, the weight/length ratio (K=Pt/Lt) was calculated using animals captured in 1981 and 2010. The nutritional condition between areas and sexes, and years and sexes, was contrasted by a bifactorial ANOVA, and the overall length and weight of lobsters were compared using a t-Test for independent samples and unifactorial ANOVA. It was found that the nutritional condition was significantly greater in males than in females. In addition, significant variations between zones were detected for both years. Nutritional condition of lobsters from Zone five was the highest for 1981, while it was Zone two for 2010. Lobsters nutritional state showed significant variations between years, being greater in 1981 (2.34 +/- 0.84g/mm) than in 2010 (1.96 +/- 0.49g/mm). The inter-zones variations as well as the inter-annual ones seem to be related to the reported variations of the bottom type and the vegetation cover. Seasonal variations in the abundance and distribution of benthic organisms, that constitute food for lobsters, could also be influencing. The differences between sexes, however, were assumed as a consequence of the methodology used and the sexual dimorphism of the species. Due to other K estimation methods, that do not include morphometric measurements, these differences were not detected. We suggested that the P. argus nutritional condition is a good estimator of the habitat condition. Besides, according to the applied K estimation methodology, it was found that different groups of lobsters that have resemblant nutritional condition, did not necessarily observe similarities in the overall mean length or weight, so they could exist under different habitat conditions.

Variaciones en la condición nutricional de langostas Panulirus argus (Decapoda: Palinuridae) en la región este del Golfo de Batabanó, Cuba / Variations of the nutritional condition of lobsters Panulirus argus (Decapoda: Palinuridae) in Eastern region of the Gulf of Batabanó, Cuba

Variations of the nutritional condition of lobsters Panulirus argus (Decapoda: Palinuridae) in Eastern region of the Gulf of Batabanó, Cuba. Nutritional condition can affect survival and growth rate of crustaceans, and this is mostly affected by habitat conditions. This study describes the space-temporary nutritional changes in this commercially important species. With this aim, the variations in the nutritional condition (K) of lobsters from four zones (1, 2, 4 and 5) in the Gulf of Batabanó, Cuba, were determined. For this, the weight/length ratio (K=Pt/Lt) was calculated using animals captured in 1981 and 2010. The nutritional condition between areas and sexes, and years and sexes, was contrasted by a bifactorial ANOVA, and the overall length and weight of lobsters were compared using a t-Test for independent samples and unifactorial ANOVA. It was found that the nutritional condition was significantly greater in males than in females. In addition, significant variations between zones were detected for both years. Nutritional condition of lobsters from Zone five was the highest for 1981, while it was Zone two for 2010. Lobsters nutritional state showed significant variations between years, being greater in 1981 (2.34±0.84g/mm) than in 2010 (1.96±0.49g/mm). The inter-zones variations as well as the inter-annual ones seem to be related to the reported variations of the bottom type and the vegetation cover. Seasonal variations in the abundance and distribution of benthic organisms, that constitute food for lobsters, could also be influencing. The differences between sexes, however, were assumed as a consequence of the methodology used and the sexual dimorphism of the species. Due to other K estimation methods, that do not include morphometric measurements, these differences were not detected. We suggested that the P. argus nutritional condition is a good estimator of the habitat condition. Besides, according to the applied K estimation methodology, it was found that different groups of lobsters that have resemblant nutritional condition, did not necessarily observe similarities in the overall mean length or weight, so they could exist under different habitat conditions.

En Cuba, la región del Golfo de Batabanó es la más importante zona de pesca de langosta debido a que de ella se extrae anualmente alrededor del 70% de la captura nacional. Con el objetivo de determinar variaciones espacio-temporales en la condición nutricional (K) de langostas Panulirus argus del Golfo de Batabanó, Cuba, se calculó dicha condición mediante una relación pesolargo (K=Pt/Lt), para lo que se utilizaron ejemplares de cuatro zonas (uno, dos, cuatro y cinco) del este del golfo, capturados en los años 1981 y 2010. Se encontró que en todos los casos analizados la condición nutricional fue significativamente mayor en machos que en hembras. Se detectaron variaciones significativas entre zonas en 1981 y 2010. También entre años el estado nutricional de las langostas presenta variaciones significativas, de manera que en 1981 (2.34±0.84g/mm) fue mayor que en 2010 (1.96±0.49g/mm). Tanto las variaciones interzonales como las interanuales parecen estar relacionadas con variaciones reportadas en el tipo de fondo y la cobertura vegetal. Variaciones estacionales en la abundancia y distribución de organismos bentónicos que constituyen alimento para las langostas también podrían estar influyendo. Las diferencias entre sexos en cambio, se suponen consecuencia de la metodología utilizada y del dimorfismo sexual característico de esta especie, por cuanto otros métodos de estimación de K que no involucran mediciones morfométricas, no detectan estas diferencias.