Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

Information concerning Neastacilla californica is currently scarce. In fact, its distribution range is not yet well defined; this species is currently reported from Point Conception to Point Loma along the California coast, USA, and also in the Gulf of California, Mexico. In this note, we present a new zoogeographical record of N. californica with information derived from a sample of taken in July 2012 during a monitoring expedition in the area inside of the Guerrero Negro Lagoon, at Peninsula de Baja California, Mexico, at 4.3 latitudinal degrees from the southernmost point reported on the Pacific coast. Additionally, we present a comparative summary of the main diagnostic features of this species and a series of photographs that allow observing characteristics of N. californica, contributing to the knowledge of the species.

The objective of this study was to assess the L-lysine effect in silver catfish, Rhamdia voulezi female reproduction. Four hundred fish were used distributed in a random in 16 net cages (25 fish each × 4 replicates = 100 fish per treatment). The treatments consisted in four diets, isoproteic and isoenergetic (30% crude protein and 3,500 kcal kg-1 digestible energy) with different L-lysine levels: T1: 1.30; T2: 1.40; T3: 1.60 and T4: 1.95%. After 185 days of experiment 18 females per treatment were weighed, measured, and submitted to hormonal induction (0.5 and 5.0 mg kg-1 Carp Pituitary Extract). The females were then sacrificed and had their ovaries, liver and fat removed and the respective organosomatic indices were estimated. With regard to the reproductive parameters, the released oocytes, absolute fecundity and remaining ovaries were influenced (P < 0.05) by the diet, and the highest mean values were observed in the treatment with 1.95% L-lysine. Among the organosomatic indices, only the visceral fat was influenced (P < 0.05). The estradiol levels and the composition of essential amino acid in oocytes were not affected (P > 0.05). We can conclude that L-lysine affects the reproductive parameters and accumulation of visceral fat in R. voulezi.

First description of Aegla denticulata Nicolet, 1849’s predatory behavior upon Geotria australis Gray, 1851’s ammocoetes larval stage, in a confined artificial environment.

This study aimed to determine weight-size relationships and to fit the best growth model of the Cortez oyster Crassostrea corteziensis from early juvenile to adult during one single culture cycle. The morphometric data (n = 50 oysters sampled each two weeks during January 2010 to March 2011) of shell heightshell length [SH-SL], shell height-shell width [SH-SW], shell width-shell length [SW-SL], body weight-shell length [BW-SL], body weight-shell height [BW-SH] and body weight-shell-width [BW-SW] (log-transformed) were determined by regression analysis. The SL and SH measurements (R2 = 0.98) were consistently proportional to the BW, being the BW-SL and BW-SH morphometric relationships the more suitable for growth evaluation of C. corteziensis in culture. Four different equations of the Schnute model, as well as Special cases 1 and 2 (equivalent to the Von Bertalanffy growth model, VBGM, and Logistic models, respectively), were evaluated utilizing length-at-age data to estimate individual growth parameters. The parameters were obtained using the maximum likelihood algorithm and the Akaike information criterion was applied to rank the models examined. The growth curve displayed a rapid increase until the size of 41.68 ± 16.18 mm in length. In the present study, the symmetrical sigmoid curve was the best hypothesis that fit the data; however, it is assumed that the age data are sufficiently informative to describe the growth pattern of C. corteziensis, with either Schnute model Special case 2. Results from morphometry and growth model in this study represent useful tools to analyze growth performance of the Cortez oyster in culture better.

Lemna gibba freshwater macrophyte and seaweeds Ulva lactuca of the middle basin Papaloapan River, southeast of Mexico were chemically characterized in their nutrients and bioactive compounds for possible use in the formulation of functional foods. The proximate chemical analysis showed that ashes contents (g 100 g-1 sample) of L. gibba and U. lactuca were 20.10 and 33.07, crude protein 21.5 and 17.2, lipids 4.45 and 1.7, nitrogen-free extract 32.4 and 38.34, respectively. Significant differences (P < 0.05) were found in the chemical composition between the two species of aquatic plants. L. gibba resulted in a protein source, and U. lactuca resulted in an energy source. They had eight essential amino acids for fish and other aquatic species and were abundant in lysine and methionine. Both aquatic plants had an essential quantity of inulin (functional fiber) this data not been reported. Also, they had xanthophyll and variety of antioxidant (β-carotenes, lutein, lycopene and neoxanthin). L gibba had only had one polyunsaturated fatty acid (PUFA; α-linolenic (ALA) 30.31 mg g-1). U. lactuca had a variety of essential PUFA´s (ALA, LA, AA; 3.93, 6.73 and 0.41 mg g-1 of fatty acids, respectively). Based on these results, both of the aquatic plants of the middle basin Papaloapan River studied are susceptible to take advantage in the formulation of functional food, since according to the literature the compounds identified have shown beneficial effects as immunonutrients, immunostimulants, antioxidants or modulators of intestinal flora. In aquaculture production, it is suggested to prove the combined use of these two plants as functional ingredients or some particular component in the diets as prevention strategy of diseases as well as to promote aquaculture sustainable through the use of these plants in the productions.

The leopard grouper Mycteroperca rosacea is endemic to northwestern Mexico. It has been classified as vulnerable by the IUCN since 2008. M. rosacea has high commercial value and is caught yearround in Baja California Sur (BCS). Biological information on this species, especially in its natural environment, is scarce, and the objective of this study was to analyze its reproductive biology in Santa Rosalía, BCS. A total of 345 specimens were collected from March 2014 to May 2015. The sex ratio was 2.0: 1.0 (females: males, P < 0.05). Population size at first maturity (L50) was estimated at 40.77 cm TL; 37.31 cm TL for males and 42.44 cm TL for females. Gonadic development was synchronous by group, with a reproductive period occurring from March to May in 2014 and 2015 (at 20-23ºC). The gonadosomatic index achieved maximum values in May 2014 and March 2015, as did the highest frequencies of mature and spawning individuals, indicating that there was a clear seasonal pattern of reproduction, and a negative correlation with temperature for both sexes. The hepatosomatic index and the condition index indicated that M. rosacea is not a species that requires storing of energy for reproductive events, as it seems to have food available year-round.

Stock discrimination is essential for biomass population assessment and essential for the fisheries management. The analysis of shape differences in anatomical structures (e.g., body shape, otoliths, scales) has been relevant issue in the study of population structure. We evaluated the hypothesis on the existence of a stockstructured population of Pacific thread herring Opisthonema libertate in the northwestern coast of Mexico. Geometric morphometric methods were used to analyze body and otolith shape. Samples come from at three commercial fishery-landing sites: Magdalena Bay, Guaymas, and Mazatlan, Mexico. Results based on body and otolith shape support the existence of different morphotypes by location. Body shape allowed better discrimination than otolith shape. The differences observed between the phenotypic stocks suggest seasonal movements, which are linked to the marine current system in this region, particularly to the California Current and the North Equatorial Counter Current.

Hippocampus patagonicus is classified as endangered in the vulnerable category by Brazilian law (MMA, 2014), and by IUCN (International Union for Conservation of Nature) criteria. Thirteen boats from the commercial fishing fleet of southern Brazil were monitored for 17 months to supplement data for the evaluation of this species. Three seahorse collection points were established, where the fish are landed: port of Imbé/Tramandaí and port of Passo de Torres (northern coast (NC) of Rio Grande do Sul) and the port of Rio Grande (southern coast (SC) of Rio Grande do Sul). The presence of H. patagonicus was recurrent, and the collected animals were between 22 and 130 mm in height. The species was captured from 11 to 57 m deep as bycatch of significant transboundary marine resources (Brazil, Uruguay, and Argentine). In bycatch of gillnet fishing (NC), estimated capture was 0.68 ± 0.97 seahorses/month/vessel, annually, an average of 89.76 seahorses would be removed from the sea by the 11 vessels involved. In trawling (SC), it was 49.66 ± 64.86 seahorses/month/double-rig trawl. It is estimated that 8,342 seahorses are removed annually as bycatch, only in this mode of fishing. The information obtained reinforces the need to apply ecosystem management to fisheries for the recovery of stocks that are over-exploited and accompanying fauna as well, especially small species with poorly known life histories such as H. patagonicus.

The aim was to determine the growth and survival of males of the Cryphiops caementarius shrimp fed with diets supplemented with common salt. Three experimental diets supplemented with 1, 2 and 3% of common salt and a control diet without common salt were used, with three replicates, respectively. Twelve aquariums (55 L) were used and six individual culture containers (284 cm2) installed in two groups of three levels were introduced into each one. In each culture, the container stocked a shrimp, and in total six shrimp per aquarium was randomly stocked. Seventy-two male shrimps (3.87 g in weight) were used. The experiment lasted 90 days. Results indicated that the diet supplemented with 2% of common salt favored the growth in weight of shrimp males, and it was only different (P < 0.05) with the diet with 3% common salt that caused slow growth in weight. Diets with common salt did not affect shrimp survival (P > 0.05).