Selectividad de red de encierro para Lisa (Mugil Incilis), Ciénaga Grande de Santa Marta

Introducción. La Ciénaga Grande de Santa Marta es uno de los ecosistemas estuarinos de mayor importancia ambiental, social y económica del Caribe colombiano. Sin embargo, sus pesquerías causan un fuerte impacto sobre las poblaciones ícticas que allí habitan. Objetivo. Se realizó un muestreo experimental de las capturas de lisa (Mugil incilis) con red de encierro “boliche”, a fin de estimar los parámetros de selección. Materiales y métodos. Se compararon y evaluaron las capturas realizada con paños de red de 2, 2½ y 3 pulgadas Los parámetros de selectividad fueron estimados a partir del método SELECT. Las curvas de selectividad se ajustaron utilizando el software estadístico R; mientras que los análisis comparativos de la captura por unidad de esfuerzo fueron realizados mediante la prueba de Kruskal Wallis. Resultados. Las redes de encierro menores a 2½ pulgadas tienen un efecto directo sobre la estructura de tamaños de lisa y consecuentemente sobre la sostenibilidad de esta pesquería.Las redes de encierro deben considerar la aplicación de medidas de manejo que prohíba el uso de redes con tamaño de malla inferiores a 2½ pulgadas. En términos de captura no hay diferencia estadística (P>0,05) entre 2 y 2½ pulgadas, lo que no genera un perjuicio económico para el pescador. Conclusión. El uso de redes de enmalle de Introduction. The Ciénaga Grande of Santa Marta is one of the estuarine ecosystems of greatest environmental, social and economic importance in the Colombian Caribbean. However, its fisheries have a strong impact on the fish populations that live there. Objective. An experimental sampling of the catches of lisa (Mugil incilis) with a “boliche” encircling gillnet was carried out to estimate the selection parameters. Materials and methods. Catches carry out with mesh size of 2, 2½ and 3-inch were compared and evaluated. The selectivity parameters were estimated from the SELECT method. The selectivity curves were adjusted using the R statistical software; while the comparative analyzes of the catch per unit effort were carried out encierro de 2 pulgadas o inferiores deben ser revisadas y su uso consensuado con los pescadores de la región. Palabras clave: pesca artesanal, selectividad, red de encierro, Mugil incilis, Ciénaga Grande de Santa Marta.

De novo assembly and characterization of the liver transcriptome of Mugil incilis (lisa) using next generation sequencing

Background Mugil incilis (lisa) is an important commercial fish species in many countries, living along the coasts of the western Atlantic Ocean. It has been used as a model organism for environmental monitoring and ecotoxicological investigations. Nevertheless, available genomic and transcriptomic information for this organism is extremely deficient. The aim of this study was to characterize M. incilis hepatic transcriptome using Illumina paired-end sequencing. Results A total of 32.082.124 RNA-Seq read pairs were generated utilizing the HiSeq platform and subsequently cleaned and assembled into 93.947 contigs (with N50 = 2.019 bp). The analysis of species distribution revealed that M. incilis contigs had the highest number of hits to Stegastes partitus (36.6%). Using a sequence similarity search against the public databases GO and KEGG, a total of 71.271 and 16.974 contigs were annotated, respectively. KEGG showed genes related to environmental information, metabolism and organismal system pathways were highly annotated. Complete or partial coding DNA sequences for several candidate genes associated with stress responses/detoxification of xenobiotics, as well as housekeeping genes, were employed to design primers that were successfully tested and validated by RT-qPCR. Conclusions This study presents the first transcriptome resources for Mugil incilis and provides basic information for the development of genomic tools, such as the identification of RNA markers, useful to analyze environmental impacts on this fish Caribbean species.

THE CONDITION FACTOR OF Mugil incilis HANCOCK (PISCES: MUGILIDAE) AND ITS SEASONAL CHANGES IN THE CIENAGA GRANDE DE SANTA MARTA (COLOMBIA)

The annual variation in condition of the mullet Mugil incilis Hancock has been studied in the Ciénaga Grande de Santa Marta (CGSM), The largest coastal lagoon on the Colombian Caribbean, with emphasis on the influence of such environmental factors as salinity, temperature and trasparence of the waters on the condition of this species of Mugilidae. Seasonal differences observed in condition of M. incilis are evidently related to gonadal development and depend on food availability. The diet of M. incilis is based on detritus and its food supply seems to be very influenced by river discharge which also accounts for the salinity changes in the lagoon, this explains the inverse correlation (r = -0.82) found between salinity and condition of the mullets expressed as C = 0.9949 - 0.0057 S (°/oo). Annual salinity variation follows a rhythmic pattern of seasonal changes, not precisely "in situ", but in distant continental regions: the headwaters of the tributaries of the CGSM. These mullets spawn in Caribbean waters adjacent to the CGSM and their migration period (Dec-March) begins with their best physical condition, returning to their feeding areas in the CGSM 2 or 4 weeks later, until the end of the migration, with their lowest condition since these mullets apparently do not feed at all during the spawning migration. No change related to temperature variations was observed, and turbid waters were the rule in M. incilis feeding sites.

EFECTOS DE LA PESCA SOBRE LA BIOLOGÍA REPRODUCTIVA DE LA LISA MUGIL INCILIS (PISCES: MUGILIDAE) EN LA CIÉNAGA GRANDE DE SANTA MARTA, CARIBE COLOMBIANO

The mullet Mugil incilis is one of the most important fish resources in the Ciénaga Grande de Santa Marta. Based on monitoring of fishery statistics collected in the periods 1994-1996 and 2000-2007 and biological aspects of the species between 2006 and 2007, we evaluated fishing effects on the reproductive biology of M. incilis. Fishery statistics revealed that catch and fish size declined with time. Peak spawning was observed to occur between November - December, when the gonadosomatic index and condition factor showed their maximum values, contrasting with water salinity that plunged in the rainy period. Male: female ratio was estimated as 1:3 after a sample of 1954 individuals, and mean maturity size (MMS) calculated as 23.8 cm total length (TL), lower than that previously reported. Mullet represented 30 % of the whole fish catch in the period 1994-2007, and 65 % of the individuals were found below their MMS, mainly caught with cast-nets at spawning time. Lower occurrence of larger fish in the catch seems to be a reasonable explanation for the reduction of MMS. No evidence was found to attribute this decrease to a species strategy. Management measures for this fishery are discussed and suggested.

RELACIONES TRÓFICAS DE CINCO ESPECIES DE PECES DE INTERÉS COMERCIAL EN LA BAHÍA DE CARTAGENA, CARIBE COLOMBIANO

Cartagena Bay is a highly productive habitat which supports important aquatic communities and is considered an estuarine environment. During the sampling season, fie commercial fih were captured: ladyfih (Elops smithi), machuelo (Opisthonema oglinum), mullet (Mugil incilis), sea bass (Centropomus ensiferus), and corvina (Cynoscion jamaicensis), all which stomach contents were analyzed. From all the fih captured, 82.6% presented contents in their stomachs, which were separated into 57 items, such as benthic microalgae, dinoflgellates, cyanophytes, sponges, mollusks, annelids, crustaceans, and fih. According to the Importance Relative Index (IRI), E. smithi, C. ensiferus, and C. jamaicensis were classifid as third order consumers, O. oglinum as a second-order consumer, and M. incilis as fist order consumer. The most contrasting result compared to other studies, is the found for O. oglinum, suggesting that this species is not only a fiter feeding, but also a scale eater (lepidophagy).

EFECTO DE LOS ARTES DE PESCA SOBRE EL TAMAÑO DE LOS PECES EN UNA PESQUERÍA ARTESANAL DEL CARIBE COLOMBIANO

As fundamental support for designing a management system for the fishery in the Ciénaga Grande de Santa Marta and Pajarales Complex (CGSM-PC), the effect of the most used fishing gears on the main five fish species was addressed. The fishes studied were: mapalé sea catfish (Cathorops mapale), striped mojarra (Eugerres plumieri), New Granada sea catfish (Ariopsis sp.), parassi mullet (Mugil incilis), and Nile tilapia (Oreochromis niloticus). Length frequency data for each species were available during 1994-1996 and 2000-2004 to the following gears: cast-nets, encircling gillnets, beach seines, longlines, and gill nets. In order to evaluate the gears’ effect, the mean fish size (MCS) was compared to the size at maturity (MMS) of each species, considered here as limit reference point (LRP). The MCS for each species changed through the years, between landing sites and gears. The five fish species showed an individual size reduction trend. The results indicate that M. incilis, C. mapale, and Ariopsis sp. are at high risk of overfishing, since in all cases their MCS surpass their MMS. Concerning E. plumieri, although its MCS slightly exceeded the MMS, it is not exempted of the jeopardy of overexploitation. Oreochromis niloticus was the only one species without any overfishing hazard. How technological changes affect fish resources is discussed, whereas some management measures for this fishery are proposed.

DESCRIPCIÓN DEL HÁBITO ALIMENTARIO DE DOCE ESPECIES DE PECES ASOCIADOS A LA CIÉNAGA GRANDE DE SANTA MARTA, COLOMBIA

Changes in food composition of 12 species of fishes from the southeastern part of the Ciénaga Grande de Santa Marta, Colombia were evaluated; a total of 2035 individuals were sampled. Significant changes in food composition with size, time and space were observed, mainly in Ariopsis sp., Cathorops mapale, Lycengraulis batesii, Astyanax magdalenae, and Aequidens pulcher. Regarding diet similarity between species, two main groups were observed. The first one was divided in three subgroups: one characterized by fish foraging on insects and zooplankton is composed by A. magdalenae and Roeboides dayi; the second one is composed by the generalists Ariopsis sp., L. batesii, and A. pulcher, and the third one by fish predators Caquetaia kraussii and C. mapale. The other group was characterized by fish feeding on phytoplankton and in a lower proportion on detritus and zooplankton (Oreochromis niloticus, Mugil incilis, M. liza, and M. curema) or on detritus (Cyphocharax magdalenae).

ESTRUCTURA DE LA COMUNIDAD ÍCTICA DE LA CIÉNAGA DE MALLORQUÍN, CARIBE COLOMBIANO

In order to evaluate the structure of the fish community in the coastal lagoon of Mallorquín, sampling was made each two weeks in nine stations widely allocated in the study area from July 1998 to April 1999. A total of 36 species corresponding to 22 fish families were analized. Based on the frequency of occurrence, 58% were classified as occasional visitors, 26% as frequent visitors, and a 16% as residents. Total abundance was 2424 individuals and 187 Kg of biomass (fresh weight). 89,3% of total abundance and the 89,6% of total biomass was represented by four families (Mugilidae, Engraulidae, Gerreidae and Ariidae. Four species (Mugil incilis, Cetengraulis edentulus, Diapterus rhombeus and Eugerres plumieri), included in three families, were dominant, representing 85,4% the whole sample. Species abundance, biomass y richness was homogeneous throughout the three climatic periods. Shannon-Weaver diversity index values oscillated between 0,13 and 0,33.