NOTAS SOBRE LA REPRODUCCIÓN, MORFOLOGÍA Y ECOLOGÍA DE Pareques acuminatus (TELEOSTEI: SCIAENIDAE), EN LA REGIÓN DE SANTA MARTA, CARIBE COLOMBIANO.

Pareques acuminatus (familia Sciaenidae) es una especie carnívora de tamaño pequeño, que se distribuye en el Atlántico occidental: Carolina del Norte y Bermudas hasta Brasil. Los estudios sobre la biología y ecología de P. acuminatus son escasos y en Colombia no se han realizados trabajos concernientes a la especie. El propósito de este estudio fue conocer la biología de la especie y determinar aspectos ecológicos con el fin de ampliar su conocimiento en el Caribe colombiano. Se hicieron capturas de la especie por medio de buceo libre y se realizaron censos visuales del hábitat donde fue observada. La morfometría y merística fue evaluada, se identificaron las fases reproductivas y se estimó la fecundidad parcial mediante el método gravimétrico. Un total de 85 individuos fueron recolectados con una LT entre 33 y 185 mm (123,7±36,3 mm) siendo más frecuentes aquellos entre 121-142 mm (42%) seguidos de los de 143-164 mm (20%). Se distinguieron 39 hembras, 34 machos y 12 fueron indeterminados debido a su pequeño tamaño. La talla de las hembras maduras fue a partir de una LT de 118 mm, siendo una especie asincrónica con dos fases reproductivas (en desarrollo y capaz de desove). La fecundidad parcial estimada fue de 8744 ± 3900 oocitos y la fecundidad relativa con relación a la talla fue de 64,15 ± 25,51 oocitos/mm con un diámetro de 0,53 ± 0,04 mm. Pareques acuminatus es una especie típica de hábitats arrecifales someros y se encontró acompañada principalmente de Myripristis jacobus, Canthigaster rostrata, Haemulon steindachneri, H. flavolineatum, Stegastes partitus y Chromis multilineata.

Characterization and Evolution of Dishevelled Genes in Paralichthys olivaceus

The study examined the key gene Dishevelled (Dvl or Dsh) in Wnt (Wingless and INT-1) signaling pathways. The gene (Dvl) was characterized in the flat fish Paralichthys olivaceus for its expression pattern structure and phylogenetics at the Ocean University of China in Qingdao, China in 2018. Three gene paralogues (Dvl1, Dvl2 and Dvl3) of the Dvl family were cloned in P. olivaceus and a N-terminal DAX domain, a central PDZ domain and a C-terminal DEP domain were discovered in all three protein paralogues. Phylogenetic analysis revealed that Dvl genes in P. olivaceus are most closely related to those in marine teleosts Larimichthys crocea and Stegastes partitus, followed by those in Cynoglossus semilaevis. For each Dvl gene, the genes in teleosts fall into a clade independent from the ones in other vertebrates, suggesting that the duplication of Dvl genes occurred prior to the divergence of vertebrates. The temporal expression patterns of the three Dvl genes were characterized during the embryonic development of teleosts. In P. olivaceus, all three Dvl genes remain at low expression levels during the early stages of development until gastrula stage, when the expression of Dvl1 was significantly up-regulated. The research revealed vastly different temporal expression patterns of Dvl genes and suggested that the structure of Dvl proteins is conserved, but the expression patterns of Dvl genes vary significantly among different classes.

ECOLOGÍA QUÍMICA DE LAS ESPONJAS EXCAVADORAS CLIONA APRICA, C. CARIBBAEA, C. DELITRIX Y C. TENUIS

The Caribbean encrusting and excavating sponges Cliona aprica, C. caribbaea, C. delitrix and C. tenuis (Porifera, Hadromerida, Clionaidae), aggresively undermine and displace live coral tissue. At San Andrés island and Islas del Rosario (Colombian Caribbean), in all 145 observed cases of direct contact of the sponges C. aprica, C. caribbaea and C. tenuis with 17 coral species, corals showed unhealthy signs in their tissue. It was also noticed that the surface of these sponges is colonized by few organisms and that they are rarely preyed upon. To establish the possible use of chemical substances by these sponges in competition for space with corals (allelopathy), as inhibitors of larval settlement (antifouling), and as feeding deterrents against generalist fish (antipredatory), the activity of crude organic extracts was experimentally evaluated. Extracts were prepared in methanol and 1:2 metanol:dichloromethane and incorporated in experimental media at the natural concentration within the sponges. Using an unpublished method being developed by J. Pawlik (University of North Caroline at Wilmington) and M. Ilan (Tel Aviv University), PhytagelTM disks with crude extracts of each of the four sponge species, placed on the coral Montastrea cavernosa, produced a greater degree of polyp mortality than control gels without extract. Gels with extracts of the sponges C. aprica and C. caribbaea + C. tenuis, served in Petri dishes and used as substratum in the field, inhibited significantly the settlement of fouling organisms, in comparison to control gels. In laboratory trials, wheat flour pellets with extracts C. delitrix and C. caribbaea + C. tenuis were significantly rejected by the omnivore reef damselfish, Stegastes partitus, whereas pellets with extract of C. aprica did not deter feeding. These results suggest that substances present in the crude organic extracts of these sponges may be responsible in part for their ability to compete for reef substrata and to defend themselves from potential aggressors.

DIVERSIDAD Y DISTRIBUCIÓN DE PECES EN EL GRADIENTE DE PROFUNDIDAD DE UNA PARED ARRECIFAL CORALINA EN LA ISLA DE SAN ANDRÉS, CARIBE COLOMBIANO

“Blue Wall”, in San Andrés Island (Colombia), is an outer reef slope with an inclination that increases with depth to nearly 90°. Such a steep gradient facilitates the identification of patterns of variation in species abundance and diversity along depth. To document such patterns in fishes associated with this habitat, 30 visual censuses were conducted along 30 x 2 m transects, located at 5 m intervals between 5-30 m depth, in which the abundance and diversity of species was estimated. A total of 2916 individuals belonging to 46 species from 21 families were recorded within transects. Ten additional species were observed outside of transects for a total richness of 56 species. The dominant species were Canthigaster rostrata, Chromis cyanea, Stegastes partitus, Thalassoma bifasciatum and Clepticus parrae, which together with four other species accounted for 92% of the total abundance. Several of these dominant species are planktivorous and abundant throughout the Caribbean and had broad ranges of vertical distribution with abundance peaks in different parts of the depth gradient. In general, there was a positive correlation between average abundance and breadth of depth distribution. Non-metric Multi-Dimensional Scaling analysis revealed distinct assemblages at each depth, which also differed significantly, but weakly, in their diversity and dominance, but not in their species richness and evenness. Shallow assemblages were clearly distinctive from deep ones, with greater differentiation between shallower than between deeper assemblages. We conclude that the fish assemblage at “Blue Wall” exhibits a structural order that can be explained, in part, by depth and that reef walls offer an excellent opportunity to examine processes responsible for patterns of community structure in coral reef fishes.

EVALUACIÓN DEL POTENCIAL ANTIDEPREDADOR DE LOS EXTRACTOS ORGÁNICOS CRUDOS DE QUINCE ESPONJAS MARINAS

Organisms have developed diverse mechanisms during their evolution, to defend themselves from predators and competitors, in order to ensure temporal permanence. One of these mechanisms is chemical defense. Chemical substances are used by some organisms to deter potential predators from devouring them. This paper evaluates the efficacy of the organic crude extracts of fifteen different marine sponges from the Colombian Caribbean to deter a potential predator, the generalist reef fish Stegastes partitus. It was found that Cribrochalina infundibulum extract acted as a feedingattractant to this particular predator, while only the extracts from Dragmacidon reticulata, Petromica cyocaliptoides, Neopetrosia proxima, Myrmekioderma gyroderma and Biemna cribaria were feeding deterrants; it was also observed that the latter three also presented apparent physical defenses, showing that chemical and physical defenses are not necessarily excluding.

Reef fish community in presence of the lionfish (Pterois volitans) in Santa Marta, Colombian Caribbean

ABSTRACT Objective. Fish species community structure and benthic organisms coverage were studied in five localities in Santa Marta where the lionfish is present. Materials and methods. Abundance of fish species, including lion fish, was established using 30 m random visual censuses and video transects; trophic guilds were established according to available references. On the other hand benthic coverage was evaluated using the software Coral Point Count (CPCe) 4.0. Results. Families with higher species numbers were Serranidae, Labridae, and Pomacentridae. Lionfish abundances were low (2.6±2.1 ind/120 m2), but in any case Pterois volitans was observed as the eleventh more abundant species, surpassing species of commercial value such as Cephalopholis cruentata. Species that were found in larger numbers (>100, Thalassoma bifasciatum, Haemulon aurolineatum, Canthigaster rostrata, Abudefduf saxatilis, Chromis cyanea, and Stegastes partitus) were mainly invertebrate eaters, planctivores, and territorial herbivores. Coral coverage showed higher coral percentages in Chengue (69.9%) and Cinto (27.4%), larger sponge percentages in Morro (32.7%); Isla Aguja and Remanso showed the larger figures for abiotic substrate (41.6 and 37%, respectively); corals, sponges, and gorgonians were the components best explaining fish community, but not for the lion fish, which inhabit all studied reef formations. Conclusions. Lion fish is ranked between the 20 more abundant species, with none commercially important species larger, hence no species may qualify as a natural control. Lion fish has as well become a relatively abundant species in Santa Marta reefs, independent of benthic coverage.

Brazilian tropical fishes in their southern limit of distribution: checklist of Santa Catarina’s rocky reef ichthyofauna, remarks and new records

We present a checklist of 278 species of reef fishes recorded along the coastline of Santa Catarina state, the southernmost limit of distribution of tropical ichthyofauna on the coast of Brazil. Twelve new species records for this state are presented: Acanthurus coeruleus, Acanthurus monroviae, Apogon americanus, Cantherhines macrocerus, Chaetodon sedentarius, Chromis flavicauda, Clepticus brasiliensis, Decapterus punctatus, Gymnothorax vicinus, Herpetoichthys regius, Muraena retifera and Stegastes partitus. Stegastes partitus and H. regius are reported for the first time, respectively, from the Southwestern Atlantic and for the coastal part of this region, while Acanthurus monroviae is reported for the second time for the Southwestern Atlantic. We present habitat distribution, trophic structure and comment on biogeographic affinities of this transitional region, discussing both remarkable species presences and absences.