. 2017. Length-weight relation for eleven demersal fish species in the artisanal shrimp fishery areas from the Bahia MagdalenaAlmejas lagoon system, Mexico. Acta Ichthyol. Piscat. 47 (3): 303-305.Abstract. The length-weight relations (L-W) for 11 demersal fish species from a lagoon system in south-western coast of the Baja California Peninsula, Mexico were estimated. The following species were studied: Occidentarius platypogon (Günther, 1864) . These species were caught in the artisanal shrimp fishery areas from the Bahia MagdalenaAlmejas lagoon system; thus the specimens were obtained with the shrimp trawl net. A total of 3824 specimens were used to estimate parameters of the relations. The slope (b) fell within 2.7 to 3.4 and the growth pattern was isometric in most cases (10 species), whereas for one species the growth was allometric. The L-W relation parameters for Occidentarius platypogon and Eucinostomus peruvianus, are not available in FishBase.

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Graceful mojarra (Eucinostomus gracilis) is an important component of the ichthyic fauna of lagoon systems but knowledge of its population aspects is scarce. Monthly samples in the Magdalena-Almejas Lagoon system (March-August, 2014-2017) were obtained with a trawling net. Abundance was estimated using the swept area method and its spatial variation; and the maturity size was determined using the logistic method. The sex ratio for mature and immature populations, and their length-weight relationship were estimated; FISAT was used to estimate the growth and recruitment parameters. Abundance ranged from 0.6 to 203 ind-Ha-1 with changes for each lagoon system areas and among years. Size at maturity (L50) was 132 mm in total length (TL) for the population, 129 mm TL females, and 135 mm TL males. Considering the population of the total organisms, L50 indicated that 18% were adults and 82% were juveniles. Juvenile dominance indicated that this lagoon system is used for grow-out. The smaller ratio of adult organisms does not allow asserting assertion that the priority of the area is for reproduction. E. gracilis showed moderate growth (K = 0.56 year-1) with longevity of 5.4 years and asymptotic length of L∞ = 195 mm.

Stock assessment of the geoduck clam Panopea globosa in Mexico has been based on data-poor without consideration of the biological traits of the species, promoting a passive management strategy without biological reference points for its harvest and conservation, which results in limited advice regarding the sustainability of the fishery. The stock assessment was supported on an integrated catch-at-size assessment model. The model described the population changes, including recruitment, selectivity, fishing mortality, individual growth patterns and survival over time, providing management quantities for the geoduck clam fishery, such as biomass-at-length (total and vulnerable) and harvest rate-at-length. The results indicated overfishing of the geoduck clam population; the harvest rate exceeded the management tactics established for this fishery, even the individuals smaller than the minimum legal size (130 mm) were harvested. Thus, declines in the total biomass (from 3,262 to 1,130 t) and recruitment (representing an 86% decrease) were observed from 2010 to 2012. Although the results showed a recovery trend in recruitment and total biomass from 2014 to 2016, this trend may have been due to the spatial relocation of fishing mortality.