Biology of the red mullet mullus surmuletus (mullidae) off the Canary Islands, Central-East Atlantic

The biology of red mullet Mullus surmuletus was studied from collections taken off the Canary Islandsbetween January 1991 and September 1993. Total length ranged from 12 to 33 cm, mainly between 15 and 21cm. Males ranged from 14 to 26 cm and females from 14 to 33 cm. Females dominated the larger size-classes (>18 cm). The overall ratio of males to females was 1:2.3. The reproductive period extended from February toMay, spawning peaking in March and April. The total length at 50% maturity was 16.6 cm for the whole population.The length-mass relationship for all individuals can be described by the parameters a = 0.0074 and b = 3.1826. Fish aged 0.8 years were present in the samples. The parameters of the Von Bertalanffy growth equation obtained for all individuals were: L‡ = 35.71 cm and k = 0.22.year-1. Significant differences were found in the growth parameters between males and females. The rates of total mortality Z, natural mortality M and fishing mortality F were 1.25, 0.55 and 0.70.year-1 respectively. The estimated total length at first capture was 15.74 cm

Sexuality and reproduction of annular seabream Diplodus annularis (L., 1758) (Pisces, Sparidae) off Gran Canaria (Canary Islands)

A study on the sexuality and reproduction of annular seabream Diplodus annularis (L., 1758) was conducted, based on data from 792 individuals caught off Gran Canaria (Canary Islands) between January 1998 and December 1999. The size range was 79 mm to 209 mm total length. The sexual type is proterandric hermaphroditism. Males were more abundant than females (1:0.78) in the sample, with males predominating in smaller size intervals, and females in larger ones. The spawning period extended from February to May, with a peak in March-April. The length at first maturity was 102 mm for males, and 126 mm for females.Se estudia la sexualidad y la reproducción en 792 ejemplares de raspallón Diplodus annularis (L., 1758) capturados en aguas de la isla de Gran Canaria (islas Canarias) entre enero de 1998 y diciembre de 1999. El rango de tallas oscila entre 79 y 209 mm de longitud total. El tipo sexual es hermafroditismo proterándrico. Los machos son más abundantes que las hembras (1:0,78) y predominan en las tallas inferiores; las hembras prevalecen en las superiores. El periodo reproductor se extiende desde febrero hasta mayo, con un máximo de actividad en marzo-abril. La talla de primera madurez se alcanza a los 102 mm en los machos y a los 126 mm en las hembras.Instituto Español de Oceanografí

Bioencapsulation and Colonization Characteristics of Lactococcus lactis subsp. lactis CF4MRS in Artemia franciscana: a Biological Approach for the Control of Edwardsiellosis in Larviculture

Predominance of beneficial bacteria helps to establish a healthy microbiota in fish gastrointestinal system and thus to reduce emerging pathogen. In this study, the colonization efficacy of Lactococcus lactis subsp. lactis CF4MRS in Artemia franciscana and its potential as a probiotic in suppressing Edwardsiella sp. infection were investigated in vivo. The colonization extent of the bioencapsulated L. lactis was established through visualization of gfp gene-transformed L. lactis in A. franciscana. Here, we demonstrate that when A. franciscana is administrated with L. lactis at 108 CFU mL−1 for 8 h, the highest relative percentage of survival (RPS = 50.0) is observed after inoculation with Edwardsiella sp. The total counts of L. lactis entrapped in Artemia were the highest (ranged from 3.2 to 5.1 × 108 CFU mL−1), when 108–109 CFU mL−1 of L. lactis was used as starting inoculum, with the bioencapsulation performed within 8–24 h. Fluorescent microscopy showed gfp-transformed L. lactis colonized the external trunk surfaces, mid-gut and locomotion antennules of the A. franciscana nauplii. These illustrations elucidate the efficiency of colonization of L. lactis in the gastrointestinal tract and on the body surfaces of Artemia. In conclusion, L. lactis subsp. lactis CF4MRS shows a good efficacy of colonization in Artemia and has the potential for biocontrol/probiotic activity against Edwardsiella sp. infection

Determination of the state of exploitation of the common pandora Pagellus erythrinus (Linnaeus, 1758) in Gran Canaria waters using length cohort analysis

En el presente trabajo se ensaya la aplicabilidad del análisis de cohortes en longitud para determinar el estado de explotación de la breca Pagellus erythrinus (Linnaeus, 1758) en aguas de Gran Canaria. Se analizaron 61 291 individuos procedentes de pescas comerciales efectuadas entre enero de 1990 y diciembre de 1993. La breca, especie más común en las capturas demersales efectuadas por la flota artesanal en Gran Canaria, se pesca en la actualidad con nasas de orilla y palangres de forma simultánea. El palangre incide sobre los individuos de tallas mayores y la nasa sobre las primeras clases de tallas. Se advierte una acusada sobrepesca en crecimiento de la que es responsable la nasa. La sustitución de la nasa por el palangre produciría, a corto plazo, un aumento de la producción esperable y del tamaño relativo del stock.In the present study the applicability of length cohort analysis was tested to determine the state of exploitation of the common pandora Pagellus erythrinus (Linnaeus, 1758) in Gran Canaria waters. 61 291 individuals obtained from commercial catches between January 1990 and December 1993 were used in the analysis. Common pandora, the most common species in the demersal catches of the small-scale Gran Canaria fishery, is captured by traps and longlines simultaneously. The longlines catch large individuals and the traps small individuall. The traps produce an overexploitation. The substitution al the traps by the longlines would produce, in the short term, an increase in yield and biomass.Instituto Español de Oceanografí

Reproductive period and sexual maturity of the sardine Sardina pilchardus (Walbaum, 1792) in Gran Canaria waters (Canary Islands)

The present paper discusses the reproductive period and sexual maturity of a sample of sardine Sardina pilchardus (Walbaum, 1792) (N = 831) caught off the south-west coast of Gran Canaria (Canary Islands) from January 1995 to May 1996. The size range of the fish was 4.9-23.2 cm total length, and weight ranged from 0.8 to 101.5 g. Regarding sex ratio, there was no significant difference in the number of males and females. The reproductive period extended from November to March, with most gonadal activity in January-February. Mean total lengths at 50 % and 95 % of maturity were 15.0 cm and 17.8 cm, respectively, for males, and 15.2 cm and 18.4 cm for females.Se estudian 831 ejemplares de sardina Sardina pilchardus (Walbaum, 1792) capturados al suroeste de la isla de Gran Canaria (islas Canarias) durante el periodo comprendido entre enero de 1995 y mayo de 1996. El rango de tallas está comprendido entre 4,9 cm y 23,2 cm de longitud total y el de pesos entre 0,8 g y 101,5 g. La proporción entre machos y hembras no presenta diferencias significativas de la relación teórica 1:1. El periodo reproductor se extiende entre los meses de noviembre y marzo, con un máximo de actividad gonadal en enero-febrero. Las tallas medias de primera madurez sexual y de maduración masiva se alcanzan respectivamente a los 15,0 cm y 17,8 cm de longitud total en los machos y a los 15,2 cm y 18,4 cm en las hembras.Instituto Español de Oceanografí

SFRP5 hepatic expression is associated with non-alcoholic liver disease in morbidly obese women

Background and aims. Secreted frizzled-related protein 5 (SFRP5) was recently described as a new adipokine protective for hepatic steatosis and other obesity-related complications in the mouse model. To date, SFRP5 expression in non-alcoholic fatty liver disease (NAFLD) has not been fully assessed in humans. We measured circulating SFRP5 levels and its expression in liver and adipose tissue, and evaluated its association with NAFLD in morbidly obese women.Material and methods. Fifty-four morbidly obese women undergoing bariatric surgery were included in the study. Liver biopsies were used for histology and hepatic triglyceride content quantification. Circulating SFRP5 levels were measured through enzyme-linked immunoabsorbent assay, and SFRP5 expression was performed in hepatic and adipose tissue (subcutaneous and visceral).Results. Although circulating SFRP5 levels showed a tendency to decrease with NAFLD progression, no significant differences were observed among non-alcoholic steatosis, steatohepatitis, and control subjects. Hepatic SFRP5 expression showed a negative correlation with hepatic triglyceride content (r = -0.349, P = 0.016 for mRNA and r = -0.291, P = 0.040 for SRFP5 protein) and ALT serum levels (r = -0.437, P = 0.001 for SRFP5 protein). In addition, hepatic SFRP5 protein levels were significantly lower in NASH than in control subjects (P = 0.006). Conclusion. This is the first study reporting an association of hepatic SFRP5 expression with NAFLD in humans