No abstract

The octopus fishery on the Campeche Bank (Yucatán, Mexico) is considered the third largest in the world. In Yucatán, two fleets target this resource: an artisanal fleet and a semi-industrial fleet. The artisanal fleet only catches Octopus maya, while the semi-industrial fleet catches two species, O. Maya and O. “vulgaris” Type II, because it operates at deeper waters ( > 30 m). Since there is no information on the abundance of O. “vulgaris” Type II, management is based only on O. Maya. In order to generate information about the abundance of this species, four fishing research cruises were carried out in the northeastern area of the continental shelf off the Yucatán Peninsula. Four methods (a stratified random method, a swept area, geostatistics and a weighted swept area) were applied and compared to determine the instantaneous abundance and biomass of both species in the study area. The lowest potential biomass was calculated with the geostatistical method, with values between 18.5% and 36.7% lower than the other three methods. O. “vulgaris” Type II showed the lowest biomass (37.8±3.36 t) during May and July and the highest (189.56±11.6 t) in December. Our findings revealed that the total abun­dance of both species was similar in the study area, with a geographic overlap whose amplitude changed throughout the year according to the geographic position: O. Maya dominated at approximately 88°W, while O. “vulgaris” Type II dominated towards the southeast at 87°W.

Summary: This study presents a bioeconomic analysis of artificial shelter performance in a fishery targeting a spiny lobster meta-population, with spatially allocated, individual exclusive benthic property rights for shelter introduction and harvest of species. Insights into fishers' short-run decisions and fishing strategies are also provided. Spatiotemporal bioeconomic performance of shelters located in ten fishing areas during four seasons was compared using two-way ANOVAs and Pearson correlations. Results show that there was spatiotemporal heterogeneity in bioeconomic variables among fishing areas, with mean catch per unit effort (CPUE, kg shelter -1 ) ranging from 0.42 kg to 1.3 kg per trip, mean quasi-profits of variable costs per shelter harvested ranging from USD6.00 to USD19.57 per trip, and mean quasi-profits of variable costs ranging from USD338 to USD1069 per trip. Positive moderate correlations between shelter density and CPUE (kg shelter -1 km -2 ) were found. Bioeconomic performance of the shelters was influenced by spatiotemporal resource abundance and distribution, fishing area location in relation to the port, shelter density, heterogeneous fishing strategies and the management system. The results provide empirical information on the spatiotemporal performance of shelters and fishing strategies and can contribute to management at the local-scale of a meta-population distributed throughout the Caribbean Sea and Gulf of Mexico.Keywords: spiny lobster; artificial shelters; quasi-profits; rights-based fishery management; individual transferable fishing grounds; small-scale fishery.Eficiencia bioeconómica espaciotemporal de refugios artificiales de una pesquería de langostas del Caribe (Panulirus argus) de pequeña escala, gestionada mediante derechos territoriales Resumen: Se presenta un análisis bioeconómico espacial sobre la eficiencia de refugios artificiales de una pesquería dirigida a una meta-población de langosta, gestionada mediante derechos de propiedad territorial exclusivos para instalar refugios artificiales y captura de langosta. También se proporciona información sobre las decisiones a corto plazo y las estrategias de los pescadores. Se comparó la eficiencia bioeconómica espacio-temporal de los refugios localizados en diez áreas de pesca durante cuatro temporadas mediante ANOVA de dos vías y correlación de Pearson. Los resultados muestran que hubo heterogeneidad espaciotemporal de las variables bioeconómicas entre las zonas de pesca, con una CPUE media de 0.42 kg por viaje a 1.3 kg por viaje; las cuasi-utilidades medias de los costos variables por refugio explotado oscilaron entre 6.00 y 19.57 USD por refugio, y las cuasi-utilidades medias de los costos variables por marea de 338 a 1069 USD por viaje. Se encontraron correlaciones positivas moderadas entre la densidad de refugios y la CPUE (kg refugio -1 km -2 ). La eficiencia bioeconómica de los refugios fue explicada por la abundancia y la distribución espaciotemporal de los recursos, la ubicación de la zona de pesca en relación con e...

Due to the heavy exploitation of holothurians over the last few decades, it is necessary to implement fishing regulations aimed at reversing this situation. Holothurians require specific regulations that take into account their biology and ecology. Their behavior to group and form patches as a strategy for feeding, defense and reproduction, makes them vulnerable to overfishing. The higher the population density, the higher the catchability coefficient, and because they are sedentary organisms, the catchability does not change significantly until the density is very low. Hence, the stock assessment of holothurians can be improved by analyzing their spatial distribution. This paper proposes a stock assessment technique that considers the spatial distribution pattern of the sea cucumber Isostichopus badionotus from Yucatan, Mexico. A bioeconomic spatial model was developed to explain the interactions between fishing effort allocation, quasi-profits and the population in the short term. Because of the high price of the species and the low production costs, artisanal fishers preferred to maximize short-term quasi-profits, rather than the long-term benefits they could gain with low fishing mortality rates.

The concept of beach morphodynamics was used to classify the swash zone of carbonate sandy beaches in the central part of the state of Yucatán (Mexico). Several topobathymetric profiles were analyzed to determine the slope of the swash zone, shape parameter A of Dean's model, and shoreline advance and recession. Grain size and wave data were also analyzed to determine the dimensionless fall velocity (Ω). The slope of the swash zone was in general greater during the tropical storm season than during the northerly wind (Nortes) season. Mean profile values according to shape parameter A ranged from-0.186 to-0.074. The Ω values indicated intermediate beaches with a reflective tendency. Shoreline change relative to beach width helped to identify and rank security levels of beach segments.