ABSTRACT
Se analiza la composición de la dieta del huachinango (Lutjanus peru )y del flamenco (Lutjanus guttatus ) en la costa de Guerrero,México.Los ejemplares se obtuvieron mensualmente de las capturas comerciales en tres regiones de pesca y presentaron intervalos de talla comprendidos entre 130 y 684 mm de longitud horquilla (LH)para el caso de L.peru ,y de 120 a 550 mm para L. guttatus .A partir del número y del peso de los distintos componentes alimentarios,identificados hasta el taxon más bajo posible,se calcularon los porcentajes numéricos (%N),gravimétricos (%P)y de frecuencia de ocurrencia (%FO)que fueron sintetizados como valores de importancia relativa.En los estómagos de L.peru se identificaron 68 ítems alimentarios dentro de los cuales predominan los peces (%P =50.9),los crustáceos (%P =35.6)y los moluscos (%P =7.2)mientras que el espectro alimentario de L.guttatus estuvo integrado por 88 componentes que incluyeron principalmente peces (%P =50.8)y crustáceos (%P =43.4).Ambas especies son depredadoras generalistas,con un amplio espectro de presas.Los valores de los índices de traslape de las dietas de estas especies sugieren que no existe un alto grado de competencia intraespecífica por el alimento.Con el fin de encontrar similitudes en la dieta de estos lutjánidos en varias localidades de México y Costa Rica,se realizó un análisis de conglomerados con los valores de importancia relativa de las presas,publicados en varios trabajos.Se encontró más afinidad en la dieta de aquellas especies que habitan en una misma localidad, que entre organismos de la misma especie distribuidos en diferentes zonas.Se infiere que la disponibilidad de las presas,más que la selectividad por el alimento,determina la dieta de estas especies
Feeding habits of the fishes Lutjanus peru and Lutjanus guttatus (Pisces:Lutjanidae)of Guerrero, México.Diet composition of the Pacific snapper (Lutjanus peru )130-684 mm fork length (FL)and the spotted snapper (Lutjanus guttatus )120-550 mm FL,was analyzed.Monthly samples were obtained from commercial landings in three regions off the coast of Guerrero,Mexico.Percentage by number (%N),percentage by weight (%W),and percentage of occurrence (%O)were calculated for each prey and summarized as the index of relative importance.Both species are polyphagous predators feeding on a variety of prey:Sixty-eight prey items,mainly fish (%W =50.9),crustaceans (%W =35.6),and mollusks (%W =7.2),were found in the stomach contents of L.peru ,while 88 components were identified in the diet of L.guttatus ,the most important prey being fish (%W =50.8)and crustaceans (%W =43.4).Diet overlap between species is not significant (p<0.05),indicating that competition for food is unlikely.Based on published values of the relative importance index,the diets of these Lutjanidae were analyzed considering different regions of the Pacific coast of Mexico and Costa Rica,and similarities among sites and species were discussed.The cluster analysis showed that similarities among species inhabiting in the same area are more important than within organisms of the same species living in different zones.Results suggest that prey availability rather than food selectivity, conditions the feeding behavior of these fish species
Subject(s)
Animals , Animal Feed , Competitive Behavior , Competitive Behavior/physiology , Feeding Behavior/physiology , Feeding Behavior/physiology , Perciformes/physiology , Seawater , Food Preferences , Gastrointestinal Contents/chemistry , Mexico , Pacific Ocean , Predatory Behavior/physiology , SeasonsABSTRACT
In this paper, aspects of the reproductive biology of Lutjanus peru that can be used for the fishery management are described. Samples were taken monthly in 1993 and 1994, from commercial catches in the southern coast of Guerrero, Mexico. A global sex ratio of 1:1.37 (M:F) was found, but the sex ratio was highly variable each month. The condition factor, gonadosomatic, hepatosomatic and stomach fullness indexes were analyzed. None of the morphophysiological indexes showed any clear tendency. From 377 gonads, both male and female, five developmental stages were characterized for each sex. L. peru shows asynchronous gonad development and multiple spawning. Two spawning period were observed in 1993 (March, and August-September) and three in 1994 (April-May, July-August, and November), with a maximum in August of both years. Length at first maturity for the females of L. peru was estimated at 295 mm fork length.
Subject(s)
Animals , Male , Female , Fishes , Gonads , Sexual Maturation , Fishes , Gonads , Mexico , Reproduction , SeasonsABSTRACT
In this paper we describe the feeding habits of the Red snapper (Lutjanus peru) in the southern coast of Guerrero state, Mexico. This data could be relevant to local fisheries management. In total 385 full stomachs (206 from females and 179 from males) were collected monthly in 1993 and 1994, from commercial catches. Stomach contents were identified to species level when possible. Food items were grouped into taxonomically coherent groups, and their numbers, weight and frequency of occurrence obtained. The index of relative importance (IRI) was calculated for the total sample, by month, sex and size class. In 1993, a total of 42 different food items were obtained, and 43 in 1994. Food items consisted of fishes, crustaceans, and mollusks. The grouping of prey species, genera, or families rendered 14 food groups, as follows: Mollusks, Amphipods, Copepods, Stomatopods, Penaeus vannamei, Brachiuran Larvae, Stomatopods Larvae, Family Albuneidae Larvae, Other crustaceans, Anchoa ischana, Anchoa lucida, Other fishes, Salps and Unidentified organic matter. Anchoa ischana dominated the trophic spectrum in both years. Although, Amphipods, Anchoa lucida and Other fishes had important indexes in 1994. There was high variability in the diet composition by month. Nevertheless, in 1993, from February to August, crustaceans as a whole dominated the diet. In 1994, crustaceans only dominated in March and August. No differences in food habits were found between immature fish, males and females. The diet of the Red snapper varies as they grow, although the same food groups are found always. At the adult phase, in length classes over 261 mm FL, there is some degree of specialization, as they consume more fish, particularly engraulids.