Papers by Alberto Montoya Márquez
The primary foraging areas of Green Turtle (Chelonia mydas) in the Mexican Pacific are located ne... more The primary foraging areas of Green Turtle (Chelonia mydas) in the Mexican Pacific are located near the Baja California Peninsula, although foraging areas also have been documented along the southern coast of the country. The goal of this study was to determine demographic characteristics, catch per unit of effort (CPUE), condition index (CI), and food preferences of Green Turtles in Chacahua Lagoon, Oaxaca, Mexico. This is the first study of its kind involving a foraging aggregation along the Pacific Coast of southern Mexico. Between June 2009 and May 2010, we captured 16 Green Turtles with entanglement nets and had 25 total captures. Individuals that we captured more than once spent up to six months in the lagoon. Based on size, we classified 14 turtles as adults and two as juveniles. We could not determine the sex of all turtles. The mean monthly CPUE was 0.095 turtles/100 m net/12 h, which was one to two orders of magnitude lower than those reported for Baja California foraging areas. The mean CI was 1.38, similar to that reported for other Eastern Pacific foraging sites. Eight turtles exhibited injuries, mainly on the carapace and likely from outboard engine boats. Samples of esophageal and oral cavity contents that we collected from some turtles revealed that they consumed Gracillariopsis lemaneiformis, a macroalgae species distributed in several patches throughout the lagoon. Our study provides data on a foraging aggregation of Green Turtles that may be used to guide conservation efforts and research in an under-studied region.
Daily growth increments were analyzed in otoliths of Dolphinfish in the coasts of Oaxaca and Chia... more Daily growth increments were analyzed in otoliths of Dolphinfish in the coasts of Oaxaca and Chiapas, on the central Mexican Pacific, from September 2004 to September 2005. Results showed that it is possible to count daily growth rings in the sagittae, mainly on the pararostrum zone. Seasonal growth rings were not detected, that is, longer than daily periodicity. We consider that this method is ideal to identify daily growth rings in young organisms. As specimen age and the amplitude of the growth rings diminish, these rings can be underestimated because they appear to overlap. The
Gompertz growth model best described the first growth phase (L0= 7.02, G= 3.04, g= 2.89), and the von Bertalanffy constants
were: L= 231.65 cm, W= 77.926 kg, K= 0.874, t0= 0.074. The longevity was estimated at 3.44 years. Sexual dimorphism results in differences in the weight-length relationship and the relative condition factor with males (W= 2.154 · 10-5 · L2.788, CFr= 1.04) having higher values than females (W= 4.608 · 10-5 · L2.586, CFr= 0.96), due to the presence of the bony crest in males.
An aspect to consider during the captivity of the American crocodile (Crocodylus acutus), is that... more An aspect to consider during the captivity of the American crocodile (Crocodylus acutus), is that related to the individuals growth. In order to evaluate this issue, four natural nests from La Ventanilla, Oaxaca were selected, and kept in captivity one year. Based on monthly measurements of length and weight several growth models were applied. Allometric growth was observed due to the positive relationship between length and weight. Of the two parameter growth models used, the lineal type was the most appropriated. Of the three parameter growth models used, the von Bertalanffy type was the most adequate. Mean growth for the studied individuals was 0.614 mm/day, or 1.84 cm/month. This represents low values in comparison to other studies. Therefore, we consider it important to check the conditions that prevail during captivity.
Teaching Documents by Alberto Montoya Márquez
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Papers by Alberto Montoya Márquez
Gompertz growth model best described the first growth phase (L0= 7.02, G= 3.04, g= 2.89), and the von Bertalanffy constants
were: L= 231.65 cm, W= 77.926 kg, K= 0.874, t0= 0.074. The longevity was estimated at 3.44 years. Sexual dimorphism results in differences in the weight-length relationship and the relative condition factor with males (W= 2.154 · 10-5 · L2.788, CFr= 1.04) having higher values than females (W= 4.608 · 10-5 · L2.586, CFr= 0.96), due to the presence of the bony crest in males.
Teaching Documents by Alberto Montoya Márquez
Gompertz growth model best described the first growth phase (L0= 7.02, G= 3.04, g= 2.89), and the von Bertalanffy constants
were: L= 231.65 cm, W= 77.926 kg, K= 0.874, t0= 0.074. The longevity was estimated at 3.44 years. Sexual dimorphism results in differences in the weight-length relationship and the relative condition factor with males (W= 2.154 · 10-5 · L2.788, CFr= 1.04) having higher values than females (W= 4.608 · 10-5 · L2.586, CFr= 0.96), due to the presence of the bony crest in males.