Sergio Castillo-Vargasmachuca

Effect of the initial stocking body weight on growth of spotted rose snapper Lutjanus guttatus (Steindachner, 1869) in marine floating cages

Spotted rose snapper were stocked at body weight sizes of 24.5 �} 3.7 g, 55.4 �} 3.5 g, and 110.2 �} 4.6 g in three replicated marine floating cages of 100 m3 and reared for 153 days at Santa Cruz de Miramar in Nayarit, Mexico, to determine the appropriate stocking body weight size. Caged snapper were fed twice a day with commercial pellets containing 35% crude protein during the first three months and 25% during the last two months, respectively. The water temperature of cages ranged from 25.6 to 32.3��C. Mean survival ranged from 67.5 to 74.7%. Stocking body weight sizes of snapper exerted significantly different (P.0.05) effects on the final biomass. The maximum mean weekly weight gain was 12.8 g week-1 in cages with the 110.2 �} 4.6 g body weight size. These results suggest, as a good strategy, the introduction of snappers with a total weight of 110 g for grow out in marine cages culture.

THE SIZE AT MATURITY OF THE BROWN CRAB CALLINECTES BELLICOSUS (DECAPODA, PORTUNIDAE) IN THE GULF OF CALIFORNIA

This study describes the size (carapace width, CW) at maturity of Callinectes bellicosus (Stimpson, 1859) based on samples from a coastal lagoon in the southern Gulf of California. The study was conducted since knowledge of the species in particular and the genus in general on the Pacific coast is scarce or non-existent and size at maturity is a key biological parameter for fisheries management. The collection of statistics on the crab fishery began in 1982, but landings of crab from the fishery increased exponentially until 2003. Samples were collected at the mouth of the lagoon and in the inside lagoon. A total of 651 brown crabs, including 255 females and 396 males, were processed from both sites. The crabs from the coastal lagoon showed a marked segregation of the sexes. In all, 73% of the crabs from the inside lagoon were males, and 71% of the crabs from the mouth of the lagoon were females. Immature females were predominant (78% of all females) in the inside lagoon, whereas mature females were predominant (81% of all females) at the mouth of the lagoon. Segregation according to the size at maturity was observed. The size at maturity was greater in the inside lagoon (114.08 mm CW) than at the mouth of the lagoon (103.73 mm CW). The pooled size at maturity was 107.78 mm CW. This report presents the first information on segregation by sex and maturity stage in any Callinectes species from the Mexican Pacific coast. These findings are important not only for fisheries management but also for the general biological knowledge of Callinectes species. We concluded that this study offers an improved approach for evaluating fisheries management, at least for the species studied here.

The interannual variability of size at maturity of the brown crab Callinectes bellicosus Stimpson, 1859 (Brachyura, Portunidae) in the Gulf of California

This study examines how the size at maturity (CW 50% ) of Callinectes bellicosus Stimpson, 1859 is affected by environmental variability and by the source of the data. The samples were obtained from a coastal lagoon in the eastern Gulf of California between 2000 and 2003, and in 2011. To explore for interannual variation in environmental conditions, an extended negative power-law model was used, with SSTa as the annual sum of monthly sea surface temperature anomalies and Chl-a as the monthly chlorophyll a mean in a year. The interannual variability in the CW 50% of C. bellicosus was also calculated. We found that the percent of mature female drives inter-annual variability in CW 50% and that the addition of Chl-a to the model does not contribute further to the explanation of this phenomenon. The hypothesis that environmental variations affect the reproductive dynamics of the stocks needs to be tested in this species in another area.

Analysis of crab size structure and the fishing effort applied to a crab fishery in northwest Mexico

The fishing effort of a Sinaloa crab fishery in the Gulf of California in 2014 was analysed based on fishermen’s interviews, official catches and permits, and information from a sample of fishing logbooks from five fishery cooperatives operating in four coastal lagoons that contained the daily catch from individual fishing trips. Unauthorized gear, a double-ring net (DR), was used most frequently (>70% of the fishers) for crab fishing, although authorized single-ring nets and Chesapeake traps (CT) were also used with low frequency. The estimated fishing effort was 641 boats/day in the four coastal lagoons, which was 34% more than authorized, and 818 boats/day were employed in all of Sinaloa. A total of 57 479 fishing gears were estimated for the study area, which was 49.9% greater than the maximum authorized number, and 80 822 nominal fishing gears were estimated for the entire Sinaloa crab fishery, 14.15% more than the total gear limit (70 800). The size of the mesh used in the gear was smaller than the authorized limit of 76 mm, and >50% of the catches included crabs of unlawful size. It is argued that the effort must be regulated in terms of the number of vessels, per unit time, and not the number of gears. The information from this study demonstrates a failure to monitor compliance with current regulations and thus means that other strategies for the sustainable management of the fishery, such as co-management, should be tested.

Catch—Maximum Sustainable Yield Method Applied to the Crab Fishery (Callinectes spp.) in the Gulf of California

ABSTRACT The objective of this study was to determine the maximum sustainable yield (MSY) of the crab fishery in the Gulf of California by applying the catch-MSY method. This fishery occurs in two states—Sonora and Sinaloa, along the mainland coast of the Gulf of California—and involves two species: Callinectes hellicosus and Callinectes arcuatus. The main species supporting the fishery in both states is C. bellicosus, whereas C. arcuatus accounts for 5% of crab catches in Sonora and 20%–30% in Sinaloa. The catch-MSY method uses a set of viable r–k combinations to approximate MSY. The r–k combinations are the carrying capacity k and the maximum rate of population increase r for a given stock in a given ecosystem, which are required in most production models, such as the Schaefer model, to estimate MSY. Prior carrying capacity in this study was set arbitrarily from the maximum catches in a series evaluated to 100 times the maximum catch. This range ensures the real carrying capacity could be determined if catches were at MSY sometime during the period evaluated. Maximum potential could have been realized since 2006 for the Sinaloa stock and since 1996 for the Sonora stock. The evidence for these facts is that the catch per unit of effort decreased, and reductions were observed in the mean size of individuals; these changes occurred in the Sinaloa crab fishery. All methods devoted to management procedures of fisheries stocks entail a number of criticisms, and estimations of carrying capacity and stock biomass are costly; however, because sustainable fisheries are desired and data-poor stocks are common, a simple method like catch-MSY has proved be useful in the management of the crab fishery in the Gulf of California.

Effect of organic carbon input on water and sediment quality in a lutjanid sea-cage farm

The effect of the entry of organic carbon on the sediment quality and its correlation with interfacial water and hydrographic conditions in a cage hammer farm was analyzed. The results indicate a correlation of water temperature and oxide potential Reduction in the deepest part of the water column with the organic carbon content (IOC) in the sediment. This result allows an easy access tool to know in an indirect way the organic enrichment of the sediment.

Effects of temperature and salinity on growth and survival of the spotted rose snapper Lutjanus guttatus (Pisces: Lutjanidae) juvenile.

The present study evaluates the effects of temperature (24, 29 and 34oC) and salinity (15, 25, 35 and 45 ups) on the growth and survival of L. guttatus juvenile. All experiments were performed in a recirculating system with cylindrical tanks 80 L and three replicates per treatment. A total of 360 specimens were used for the experiments. The results showed that in interaction salinity-temperature, statistically significant differences were found (P

Potential distribution of Geoduck clam Panopea globosa of the Gulf of California in a climate change Model

El cambio climatico ha roto el equilibrio natural y se ha modificado el estado de salud de las diferentes especies comerciales como la almeja de sifon. Por lo tanto, el objetivo del presente estudio fue pronosticar la distribucion de almeja de sifon Panopea globosa del Golfo de California en el ano 2050 ante un escenario de cambio climatico. Se uso el modelo de maxima entropia (MaxEnt) utilizando 12 variables ambientales que afectan la distribucion desde el punto de vista termico, quimico y biologico. El modelo de MaxEnt predijo el habitat potencial adecuado para P. globosa con altas tasas de exito ( Area Under the Curve [AUC] = 0.995). El habitat mas favorable de P. globosa se encuentra en Guaymas, Sonora, debido a la surgencia de nutrientes que benefician la produccion de clorofila-a. Para el ano 2050, el modelo MaxEnt pronostico que en Sonora se presentara una reduccion hacia la costa sur. En Santa Rosalia e Isla San Marcos, Baja California Sur, las probabilidades disminuyen de 0.70 a 0.04. Los actuales sitios de captura se notaran alterados con posibles afectaciones sociales y economicas en las comunidades litorales. La conclusion es que el estudio resulta importante para la administracion de recursos pesqueros, ya que en un escenario de cambio climatico los sitios de captura pueden modificarse.

Effect of constant temperature on growth of the arched swimming crab Callinectes arcuatus Ordway (1863) over a 360-day period

The effect of five constant temperatures (20°C, 23°C, 26°C, 29°C and 32°C) on the growth of juvenile arched swimming crabs, Callinectes arcuatus, was evaluated over a 360-day experimental period. The crabs were reared in a recirculating system. The growth rate was significantly greater (p < 0.05) at 29°C, which was close to the species-preferred temperature of 26°C. The lowest growth rate occurred at 20°C. Blue crabs grown for 360 days at 29°C were twice as large as those grown at 23°C. The findings of this study could be applied to optimise the culture conditions for this tropical crab.