Record of partial albino in the scalloped hammerhead Sphyrna lewini (Carcharhiniformes, Sphyrnidae) in the Mexican Pacific Ocean: Registro de albinismo parcial en el martillo común Sphyrna lewini (Carcharhiniformes, Sphyrnidae) en el océano Pacífico mexicano

This study reports the capture of a partial albino scalloped hammerhead Sphyrna lewini in Puerto Madero, Chiapas, Mexico. The specimen was a neonate female that measured 491 mm total length and had a total weight of 800 g. This is the first report of an albino scalloped hammerhead Sphyrna lewini in the Pacific Ocean and the second in the world. The presence of albinism could be the result of multifactorial events, although anthropogenic stressors such as excessive fishing pressure and marine pollution might be involved

Characteristics of population dynamics of Lutjanus guttatus (Pisces: Lutjanidae) in Bufadero Bay, Michoacán, Mexico

Analysis of scales of Lutjanus guttatus (Steindachner, 1869) allowed the identification of three growth rings. Similar data were obtained with kernel density method. Values of the von Bertalanffys growth equation are: L? = 96.60 cm, W? = 7,508 g, K = 0.22 years-1 and to = -0.10 years. Maximum values of the condition factor occur during February and June and were preceded by two months of high values of the gastric repletion index. Maximum reproductive period was during April and August. Recruitment periods were from November to January and April to June. The recruitment length is 16 cm. The highest values of the hepatosomatic index are during December to June and showed an inversely proportional relation to the gonadosomatic index. First sexual maturity length is 30.63 cm and its longevity of 13.5 years. Forty one percent of L. guttatus individuals captured in Bufadero Bay are sexually immature, therefore we suggest a minimum capture size of 45 cm (age 2.5 years) and a closed season from August to September

Age and growth of the scalloped hammerhead shark, Sphyrna lewini (Griffith & Smith, 1834) from the Southern coast of Sinaloa, México

Age and growth for the scalloped hammerhead shark (Sphyrna lewini) were determined from opaque bands (OBs) on postcephalic vertebrae from 109 organisms (44 females, 52 cm to 276 cm total length (TL) and 65 males, 47 cm to 245 cm TL) obtained bimonthly from commercial fisheries off the southern coast of Sinaloa state (23º45´25´´N and 106º05´15´´W to 21º52´N and 105º54´W) from January 2003 to February 2005. The Bowker test of symmetry and the Index of Average Percent Error, suggest that this ageing method represents an unbiased and precise age assessment. Results show that immediately after birth (in summer), the first OB was formed and in the next winter showed the second OB. Later it was observed that two OBs were formed each year, one during summer and the other during winter, influenced by the sea surface temperature (SST). Based on the comparison of five back-calculation methods, the best methods were FraserLee. The parameters of the von Bertalanffy growth function were, for females: L? = 376 cm, K = 0.1 year-1, t0 = -1.16 years, b = 3 and W? = 222 kg; for males: L? = 364 cm, K = 0.123 year-1, t0 = 1.18 years, b = 3 and W? = 193 kg. The standard index growth (?´) was 4.2 (s = 0.1). According to these results the largest sharks observed, a female of 280 cm TL would be 12.5 years old and a male of 281cm TL would be 11 years old

A new record of bony fish prey for the genus Isistius (Chondrichthyes: Dalatiidae) in a coastal zone of southeastern Mexico

The first report of bite wounds from cookiecutter shark in a specimen of cobia in the Southern Gulf of Mexico is described. The specimen was captured by artisanal fishery in the coastal zone of Tabasco, Mexico. It presented three bite wounds with 25 to 26 teeth marks per wound, major axis interval between 3.7 and 4.7 cm and all areas of less than 10 cm2. This is new record of a bony fish as prey of genus Isistius maybe of I. brasiliensis in coastal waters over the continental shelf, in the Southern Gulf of Mexico

Primeiro registro de albinismo na raia redonda anã, Urotrygon nana (Urotrygonidae: Elasmobranchii), no Pacífico Oriental

El albinismo es una condición genética en la cual la proteína melánica está ausente o no es funcional y ocasionalmente ha sido reportado en el grupo de los condrictios. En este trabajo se describe el albinismo total en una raya redonda enana, Urotrygon nana, hembra madura de 81 mm del ancho de disco y con un peso de 18.42 g, fue capturada por medio de arrastre de fondo a una profundidad de 40 m frente a Puerto Madero, Chiapas, Golfo de Tehuantepec, Pacífico oriental (14° 31ʼ 6ʼʼ N - 92° 26ʼ 75ʼʼ W). Se cuantificaron las características morfométricas del ejemplar albino y se compararon con las de un espécimen normal del mismo sexo. Este trabajo representa el primer registro de esta anormalidad en la familia Urotrygonidae.Albinism is a genetic condition in which the melanin pigment protein is either absent or nonfunctional and has occasionally been reported in chondrichthyes. Total albinism in an 18.42 g female adult dwarf stingray, Urotrygon nana, with an 81 mm disc width is described in this paper. The subject was caught using bottom trawl methods 40 m deep off Puerto Madero, Chiapas, Gulf of Tehuantepec, eastern Pacific (14° 31ʼ 6ʼʼ N - 92° 26ʼ 75ʼʼ W). The albino morphometric characteristics were compared with those of normal specimens of the same sex. This paper represents the first record of this abnormality in the family Urotrygonidae.O albinismo é uma condição genética na qual a proteína melânica está ausente ou não é funcional e, ocasionalmente, tem sido reportado no grupo dos condrictes. Neste trabalho se descreve o albinismo total em uma raia redonda anã, Urotrygon nana, fêmea madura de 81mm de largura de disco e com um peso de 18.42g, que foi capturada por meio de arrasto de fundo a uma profundidade de 40m em frente ao Puerto Madero, Chiapas, Golfo de Tehuantepec, Pacífico oriental (14° 31ʼ 6ʼʼ N - 92° 26ʼ 75ʼʼ W). Foram quantificadas as características morfométricas do exemplar albino e comparadas com as de um espécimen normal do mesmo sexo. Este trabalho representa o primeiro registro desta anormalidade na família Urotrygonidae

Primer registro de albinismo en la raya redonda enana, Urotrygon nana (Urotrygonidae: Elasmobranchii), en el Pacífico oriental

Albinism is a genetic condition in which the melanin pigment protein is either absent or nonfunctional and has occasionally been reported in chondrichthyes. Total albinism in an 18.42 g female adult dwarf stingray, Urotrygon nana, with an 81 mm disc width is described in this paper. The subject was caught using bottom trawl methods 40 m deep off Puerto Madero, Chiapas, Gulf of Tehuantepec, eastern Pacific (14° 31ʼ 6ʼʼ N - 92° 26ʼ 75ʼʼ W). The albino morphometric characteristics were compared with those of normal specimens of the same sex. This paper represents the first record of this abnormality in the family Urotrygonidae.O albinismo é uma condição genética na qual a proteína melânica está ausente ou não é funcional e, ocasionalmente, tem sido reportado no grupo dos condrictes. Neste trabalho se descreve o albinismo total em uma raia redonda anã, Urotrygon nana, fêmea madura de 81mm de largura de disco e com um peso de 18.42g, que foi capturada por meio de arrasto de fundo a uma profundidade de 40m em frente ao Puerto Madero, Chiapas, Golfo de Tehuantepec, Pacífico oriental (14° 31ʼ 6ʼʼ N - 92° 26ʼ 75ʼʼ W). Foram quantificadas as características morfométricas do exemplar albino e comparadas com as de um espécimen normal do mesmo sexo. Este trabalho representa o primeiro registro desta anormalidade na família Urotrygonidae.El albinismo es una condición genética en la cual la proteína melánica está ausente o no es funcional y ocasionalmente ha sido reportado en el grupo de los condrictios. En este trabajo se describe el albinismo total en una raya redonda enana, Urotrygon nana, hembra madura de 81 mm del ancho de disco y con un peso de 18.42 g, fue capturada por medio de arrastre de fondo a una profundidad de 40 m frente a Puerto Madero, Chiapas, Golfo de Tehuantepec, Pacífico oriental (14° 31ʼ 6ʼʼ N - 92° 26ʼ 75ʼʼ W). Se cuantificaron las características morfométricas del ejemplar albino y se compararon con las de un espécimen normal del mismo sexo. Este trabajo representa el primer registro de esta anormalidad en la familia Urotrygonidae

Aspectos biológicos de Lutjanus peru en Bahía Bufadero, Michoacán, México:: crecimiento, reproducción y factores de condición

Some biological aspects of Lutjanus peru (Pisces: Lutjanidae) collected from Bufadero Bay in Michoacan, Mexico, were analyzed. Scale analysis allowed determining four growth rings. Similar data were obtained with an indirect method (Kernel density estimates). Results of von Bertalanffy fs growth equation obtained by simple linear method were: L= 81.12 cm, W= 4,839 g, K= 0.24 years-1 and to = -0.39 years. The maximum values of the repletion index and condition factor occurred during February, April and June. Spawning peaks occurred between February and August. Recruitment periods in the area were from January to July for those born in August, and August to December for the ones born in February. Recruitment length of the fishing gear is 18 cm which occurs after age one. The gonadosomatic index is inversely proportional to the hepatosomatic index. Length of first sexual maturity is 25.45 cm. Longevity of L. peru is estimated to be at least 12 years. In Bufadero Bay, 65.84% of the catch is on sexually immature organisms, therefore we suggest that fishing captures should consider specimens larger than 45 cm (age 3 years) and a closed season for August and September.Se estudian algunos aspectos biologicos de Lutjanus peru (Pisces: Lutjanidae) recolectado en la Bahia Bufadero, Michoacan, Mexico. El analisis de escamas permitio identificar cuatro anillos de crecimiento, valores similares fueron obtenidos por medio de los estimadores de densidad de Kernel. Los resultados de la ecuacion de crecimiento de von Bertalanffy obtenidos por el metodo lineal simple fueron: L= 81,12 cm, W= 4.839 g, K= 0,24 anos-1 y to = -0,39 anos. Los maximos valores del indice de replecion y del factor de condicion ocurren durante los meses de febrero, abril y junio. Los periodos de maxima reproduccion ocurren durante los meses de febrero y agosto. Los periodos de reclutamiento al area son de enero a julio para los nacidos en agosto, y de agosto a diciembre para los nacidos en febrero. El tamano de reclutamiento al arte de pesca es de 18 cm. El indice gonadosomatico muestra una relacion inversamente proporcional en relacion al indice hepatosomatico. La longitud corporal de L. peru en su primera madurez sexual es de 25,45 cm y su longevidad es de 12 anos. El 65,84% de la pesca en Bahia Bufadero es de organismos sexualmente inmaduros, por lo que se propone como talla minima de captura una longitud de 45 cm (edad 3 anos) y un periodo de veda para agosto y septiembre