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

In the northwestern Atlantic the genus Lagocephalus is represented by 2 species: Lagocephalus lagocephalus, with an oceanic distribution, and Lagocephalus laevigatus, of coastal habits. In the present work the first records of the species in the Gulf of Mexico and Caribbean waters off Mexico are presented, with 18 adult and juvenile specimens being captured. The adults reached sizes of 360–484 mm standard length (SL) and weighed between 845 and 1,900 g, and the sizes of the juveniles ranged between 24 and 30 mm SL, with weight ranging between 1 and 10 g. Specimens were caught using a mid-water net (NMWT 25/25), a surface longline, and a bottom longline in neritic and oceanic waters of the exclusive economic zone in the Gulf of Mexico and the Caribbean Sea off Mexico, at depths ranging from 30 to 312 m. The presence of L. lagocephalus may be associated with the climatic conditions of the nortes season, when strong winds blow towards the coastal region, and with the reproductive phase of the species.

The effects of temperature, irradiance, and other environmental variables on photosynthesis in seagrasses are well understood. However, little information is available regarding the effects of the nitrate concentration in seawater on the photosynthetic characteristics of marine vegetation. Thus, the aim of this study was to determine the effect of the nitrate concentration in seawater on the effective quantum yield of the seagrass Cymodocea nodosa. Cymodocea nodosa shoots were incubated under different irradiance levels and with different nitrate concentrations. In contrast, a decrease in transmittance and an exponential increase in the absorptance of the shoots were observed as a function of increasing nitrate levels. Furthermore, the effective quantum yield of photosystem II (ΦPSII) in C. nodosa shoots increased exponentially as the nitrate concentration in the media increased. The ΦPSII values in the shoots decreased as irradiance increased and reached minimum values at solar noon or 2 h afterward. However, the decrease of ΦPSII values was 4-fold greater in shoots incubated under full solar radiation (100% natural incident irradiance, Eo) compared to those of shoots incubated with 20% Eo. The ΦPSII values decreased to almost zero in shoots pre-incubated with no nitrate (0 μM NO3–), whereas ΦPSII values in shoots pre incubated with 25 and 100 μM NO3– decreased by approximately 25% of their initial values. Collectively, these results indicate that nitrogen levels in seawater regulate the effective quantum yield values of C. nodosa, which suggests that the photosynthetic characteristics of this seagrass might be regulated by fluctuating nitrate levels in the water column such as those that are observed in upwelling regions.

The aim of this study was to provide a first approximation of the growth, reproduction, and length–weight relationships of Symphodus ocellatus in the southeastern Black Sea, Turkey. A total of 320 specimens (273 males, 47 females) were collected between June 2015 and May 2016, and their biological parameters were estimated for each sex and both sexes combined. Total length ranged from 6.90 to 13.70 cm and the parameters (a, b) in the power length–weight relationships were a = 0.065 and b = 2.38 for males and a = 0.102 and b = 2.20 for females. Age was successfully estimated by commonly accepted procedures for otolith analysis. The von Bertalanffy growth parameters from the otolith age estimation were L∞ = 12.66 cm, k = 0.764, and t0 = –1.151 (0–3 years) for males, and L∞ = 14.15 cm, k = 0.764, and t0 = –0.188 (1–3 years) for females. The monthly gonadosomatic index values reflected a spawning period between April and July, with a spawning peak in May–June. The present study provides the first estimate of the growth and reproduction of S. ocellatus in the southeastern Black Sea of Turkey and compares the results with those from other areas.

Sandy beaches are among the most extensive coastal ecosystems in Brazil and constitute important buffer zones between terrestrial and marine environments. The present study aimed to analyze the distribution and spatiotemporal variation of the meiofaunal community of an urban tropical sandy beach in northeastern Brazil with a particular focus on nematofauna. We set up 4 transects during 2 sampling periods to evaluate different beach zones. The meiofauna comprised 8 taxa, and the nematofauna consisted of 5 orders, 16 families, and 45 genera. The meiofaunal communities followed the qualitative-quantitative standards of those of other tropical sandy beaches in northeastern Brazil. The nematofaunal community showed variation in its composition and trophic structure between dry and rainy months, which were not significantly correlated with granulometric characteristics. This suggests that other variables may influence the structure of nematofaunal communities in Gaibu Beach. Further research on the biodiversity of the meiofaunal communities on sandy beaches in northeastern Brazil is urgently needed given the lack of available information of these environments and the extreme stress they are currently under.

The Peruvian moonfish (Selene peruviana) is an important fisheries resource that is landed in the main fishing harbors of Ecuador. At the local level, little information is available regarding the biology of this species, which hinders the development of management plans. The present study evaluates the reproductive characteristics of S. peruviana such as the size at sexual maturity and reproductive cycle. Specimens were obtained from artisanal and industrial catches from January 2017 to December 2018. The morphometric characteristics, sex, and maturity stage of 886 specimens were determined, and the gonadosomatic index (GSI), hepatosomatic index (HSI), and relative condition factor (Kn) were estimated. The length-weight relationship and length at sexual maturity (L50) were evaluated with an allometry equation and multi-model analyses, respectively. The mean capture size (total length, TL) was 23.62 cm for males and 22.97 cm for females. A sex ratio (M:F) of 0.70:1.00 (χ2 = 26.28, P < 0.05) was obtained. The allometric factor of the length-weight relationship for both sexes (b) was 2.63 (t = 12.16, P < 0.05), and the coefficient of determination (r2) was 0.89, which suggests that negative allometric growth was present. The L50 (TL) was estimated to be 22.61, 23.86, and 23.27 cm for males, females, and sexes combined, respectively. The monthly GSI, HSI, and Kn values were significantly different (K-W, P < 0.05) among study months. The maximum GSI values were observed in February and March, which constituted the period of highest reproductive activity. The HSI and Kn values exhibited similar trends. The size at sexual maturity was similar to the average catch size, which could indicate that S. peruviana is currently at the limit of its optimal catch size.

Natural spawning of the leopard grouper (Mycteroperca rosacea) was studied in captivity from 2004 to 2008 under natural photoperiod conditions. Fish spawned naturally in 2006, but only 90,000 unfertilized eggs were collected. A total of 43 and 27 spawning days were observed in 2007 and 2008, respectively. Spawning season began in March and lasted until May–June and was related to an increase in water temperature from 21.1 to 23.8 °C. The mean (SE) number of eggs released each day was 101,705 (13,876) in 2007 and 40,510 (7,874) in 2008, and the total number of eggs collected in 2007 and 2008 was 4.37 × 106 and 1.07 × 106, respectively. The number of eggs collected per month was not significantly different within each year (P > 0.05), although a significant difference was observed between 2007 and 2008 (P < 0.05). The annual relative number of eggs released was 288,750 eggs·kg–1 in 2007 and 72,919 eggs·kg–1 in 2008, and viable egg production was 184,800 eggs kg–1 in 2007 and 25,375 eggs kg–1 in 2008. The fertilization rate (%) of the eggs collected daily differed significantly throughout the spawning season of 2007 (P < 0.05). The fertilization rate also differed (P < 0.05) between 2007 (61.10%) and 2008 (32.30%). Statistical analysis of the 2 consecutive spawning seasons indicated no correlation between the fertilization rate and fecundity. The effect of the moon phase on spawning was also considered. The fish spawned at dusk before total darkness. Mean (SD) egg diameter was 864.0 ± 22.0 μm.

Ulcerative and necrotizing dermatitis (UND) is a cutaneous disease caused by traumatic skin lesions on the necks of sea turtles. In this study we report the first findings of UND in free-ranging olive ridley turtles (Lepidochelys olivacea) in La Escobilla, Oaxaca, Mexico. We found several skin injury conditions on the necks of nesting turtles in the arribada events of the 2021 nesting season. Samples from injuries were taken with sterile swabs for bacteriological analyses, and antimicrobial resistance profiles were studied. Of the 525 turtles examined, 278 had injuries on the back of the neck (52.9% prevalence). Two bacteria (Pseudomonas sp. and Staphylococcus sp.) and 1 fungus (Candida sp.) were identified in 8 turtles with UND. Ciprofloxacin was the only antibiotic with high inhibition of Staphylococcus sp. and Pseudomonas sp. We recommend initiating a continuous monitoring program to follow the occurrence of dermatitis disease in L. olivacea in subsequent years to better document prevalence and progression of skin injuries in more individuals.

Daily growth rates and pelagic larval duration were investigated in the common two-banded seabream (Diplodus vulgaris). Fish were sampled using a beach seine from the shallow waters of Gökçeada Island, Turkey, between June 2013 and June 2014. The minimum and maximum daily age estimates were 41 and 339 d, respectively. The mean daily growth rate of young-of-the-year D. vulgaris was 0.330 mm·d–1. Our results showed that D. vulgaris exhibits a Type Ia settlement-mark with a pelagic larval duration of 29 d. The hatching period occurred from November to April. The maximum hatching frequencies were observed in winter, when the water temperature was relatively low. The natural logarithm of young-of-the-year abundance data was plotted against age, and the instant mortality coefficients were estimated. The relationships between total length and otolith morphometric measurements (otolith length [OL], width [OW], and radius [OR]) were defined by linear equations. Furthermore, it was observed that this ratio exhibited a linear relationship with OL, OW, and OR and total length and daily age.