Brain levels of nonapeptides in four labrid fish species with different levels of mutualistic behavior.

There is strong evidence that brain nonapeptides are implicated as modulators of a wide array of social and reproductive behaviors in fishes. However, the question remains, as to whether there is a link between the distribution of active nonapeptides across brain regions and fishes specific behavioral phenotypes. To explore this link we compared the nonapeptides' profile across the brains of fishes representing different degrees of mutualistic behavior (here: cleaning behavior).

Forebrain neuropeptide regulation of pair association and behavior in cooperating cleaner fish.

Animals establish privileged relationships with specific partners, which are treated differently from other conspecifics, and contribute to behavioral variation. However, there is limited information on the underlying physiological mechanisms involved in the establishment of these privileged ties and their relationship to individual cooperation levels. The Indo-Pacific bluestreak cleaner wrasse Labroides dimidiatus often forages in mixed-sex pairs when cleaning fish clients.

Cortisol modulates vasotocinergic and isotocinergic pathways in the gilthead sea bream.

In the present study, we assessed the responses of the vasotocinergic and isotocinergic systems to chronic stress induced by cortisol administration in the gilthead sea bream (Sparus aurata). Pituitary and plasma arginine vasotocin (AVT) and isotocin (IT) levels, as well as hypothalamic pro-vasotocin (pro-VT) and pro-isotocin (pro-IT) mRNA expression levels, were analysed. In addition, the mRNA levels of three receptors, AVTR type V1a2, AVTR type V2 and ITR, were analysed in several target organs associated with the following physiological processes: (i) integration and control (hypothalamus), (ii) metabolism and its control (liver and hypothalamus), (iii) osmoregulation (gills) and (iv) stress response (head kidney).

Distribution of small phytoflagellates along an Arctic fjord transect.

Phytoflagellates <10 μm substantially contribute to the abundance, biomass and primary production in polar waters, but information on the distribution of specific groups is scarce. We applied catalysed reporter deposition-fluorescence in situ hybridization to investigate the distribution of total phytoflagellates and of eight specific groups along a 100 km transect west off Kongsfjorden (Spitsbergen) from 29 to 31 July 2010. Phytoflagellates contributed to >75% of the depth-integrated abundance and biomass of total eukaryotes <10 μm at all stations.

Antibiotic resistance and prevalence of class 1 and 2 integrons in Escherichia coli isolated from two wastewater treatment plants, and their receiving waters (Gulf of Gdansk, Baltic Sea, Poland).

In this study, antimicrobial-resistance patterns were analyzed in Escherichia coli isolates from raw (RW) and treated wastewater (TW) of two wastewater treatment plants (WWTPs), their marine outfalls (MOut), and mouth of the Vistula River (VR). Susceptibility of E. coli was tested against different classes of antibiotics.

Changes in brain arginine vasotocin, isotocin, plasma 11-ketotestosterone and cortisol in round goby, Neogobius melanostomus, males subjected to overcrowding stress during the breeding season.

In natural spawning grounds, breeding round goby, Neogobius melanostomus, males are exposed to various social stimuli, including high density of same-sex competitors and separation from females. We hypothesize that breeding males subjected to overcrowding in the wild experience high stress that affects their socio-sexual behavior and their relationships among conspecifics. We designed an experiment to mimic natural stimulation when highly aggregated breeding males are subjected to same-sex opponents.

Age and growth of the round goby Neogobius melanostomus in the Gulf of Gdańsk several years after invasion. Is the Baltic Sea a new Promised Land?

The ages of 8 to 23·5 cm total length (L(T)) round goby Neogobius melanostomus collected monthly during 2006 and 2007 in the Gulf of Gdańsk (Baltic Sea) ranged from 2 to 6 years, with age class 4+ years dominant. Males were larger at age than females. The fastest growth occurred in the first 2 years of life in both sexes.