CARACTERIZAÇÃO DA PESCA COM REDE SERREIRA NO MUNICÍPIO DE RAPOSA-MA = CHARACTERIZATION OF FISHING WITH DRIFT GILLNET IN THE MUNICIPALITY OF RAPOSA-MA

Com o propósito de estimar a produção do peixe serra (Scomberomorus brasiliensis) e de sua fauna acompanhante, foram acompanhados desembarques de uma embarcação componente da frota serreira que atua ao longo do litoral maranhense e está sediada no município de Raposa. O controle nos desembarques caracterizou a composição e abundância dos pescados no período de janeiro de 2009 a dezembro de 2010, totalizando 17 desembarques. Um total de 27 espécies pertencentes a 16 famílias e 8 ordens, foram registradas nos desembarques. Em relação ao peso, a família Scombridae superou as demais, representando 50,02% da biomassa, seguida da Sciaenidae (21,60%) e Carangidae (11,13%). As 6 principais espécies desembarcadas, respondem por 81% do total desembarcado, destacando-se Scomberomorus brasiliensis, Cynoscion microlepidotus e Sarda sarda. Das espécies capturadas, 74,07% foram classificadas como acidentais, as espécies acessórias não ultrapassaram 14,81%, enquanto as constantes foram representadas em menos de 11,11% dos desembarques. O rendimento médio estimado das pescarias na região foi de 361 Kg/hora.AbstractTo estimate the production of Spanish mackerel (Scomberomorus brasiliensis) and its by-catch were accompanied by a landing craft fleet serreira component that acts along the coast of Maranhão and is based in the Raposa. The control landings characterized the composition and abundance of fish in the period January 2009 to December 2010, a total of 17 landings. A total of 27 species belonging to 16 families and eight orders were recorded in the landings. A total of 27 species belonging to 16 families and 8 orders were recorded in the landings. Regarding weight, the family Scombridae surpassed the others, representing 50.02% of the biomass, then the Sciaenidae (21.60%) andCarangidae (11.13%). Six species account for approximately 81% of total landings, most abundant being Scomberomorus brasiliensis, Cynoscion microlepidotus and Sarda sarda. Of the species caught, 74.07% were classified as accidental, the species accessory did not exceed 14.81%, while the constants were represented in less than 11.11% of the landings. The estimated average yield of the fisheries in the region was 361 kg / hour.

The effect of mercury, copper, and zinc on paraoxonase (PON) enzyme activity in Bonito (Sarda sarda) fish

Since heavy metal dirtiness, which we frequently encounter in environmental pollution causes harmful effects on the organism through biochemical enzyme reactions, in this study, the effects of mercury (Hg+2), copper (Cu+2), and zinc (Zn+2) heavy metal ions, which are common in environmental pollution, on PON (paraoxonase) enzyme activity in muscle tissue of bonito (Sarda sarda) were investigated. In the study, 25 bonito (S. sarda) fish muscle tissues freshly obtained from the Samsun region sea were used. The changes in PON enzyme activity were determined by adding different volumes of heavy metal solutions. PON enzyme activities of Hg+2 heavy metal ion used in different volumes were calculated as 30.9383 U/mLdak, 29.0598 U/mLdak, 26.3799 U/mLdak, 23.9443 U/mLdak, 20.6725 U/mLdak, PON enzyme activities of Cu+2 heavy metal ion used in different volumes were calculated as 19.7949 U/mLdak, 19.4807 U/mLdak 19.1864 U/mLdak, 19.1200 U/mLdak, 18.9037 U/mLdak and PON enzyme activities of Zn+2 heavy metal ion used in different volumes were calculated as 23.8305 U/mLdak, 23.0781 U/mLdak, 22.9073 U/mLdak, 22.4324 U/mLdak, 21.8159 U/mLdak. As a result of these obtained data, activity (%) values were calculated and activity (%) graphs were drawn. As a result of the study, it was determined that increasing concentrations of Cu+2 and Zn+2 heavy metal ions caused a decrease in PON enzyme activity, but there was no statistically significant difference between the different concentrations used. It was determined that increasing concentrations of Hg+2 heavy metal ion inhibited the PON enzyme activity, caused a statistically significant decrease between the activities depending on the different concentrations used (p < 0.05).

The impacts of ultrasound-assisted protein hydrolysate coating on the quality parameters and shelf life of smoked bonito fillets stored at 4±1ºC

Innovative bioactive protein hydrolysates (PH), produced from Rainbow trout (Oncorhynchus mykiss W., 1792) by-products, were used as a coating on smoked fillets of bonito (Sarda sarda) for extension of the quality and shelf life during chilled storage for 60 days. Three fillet groups were prepared as control group without coating (CG), normal hydrolysate coated group (NHCG), and ultrasound-assisted hydrolysate coated group (UHCG). Total volatile basic nitrogen (TVB-N) and TBA values exceeded the acceptable limits on the 39th and 33rd days for CG respectively; 60th day for NHCG and UHCG. However TBA of UHCG was significantly lower than NHCG. Total aerobic mesophilic bacteria (TAMB) and total aerobic psychrophilic bacteria (TAPB) loads reached 6.32±0.06 and 7.30±0.12 log cfu/g for CG on the 39th day. TAMB and TAPB values of NHCG and UHCG have remained within the limits of consumable until the end of the storage. PH coatings prolonged the storage of fillets by delaying chemical, physical, and microbial degradation. Results showed that ultrasound-assisted PH could be used as a coating for smoked bonito at refrigerated conditions, delaying oxidation and microbial degradation.

Plastic Occurrence in Commercial Fish Species of the Black Sea

The occurrence of micro- (<5 mm), meso- (5–25 mm) and macroplastics (>25mm) was investigated in seven commercial fish species of the Black Sea. Plastics were found in gastrointestinal track of all species analysed: Engraulis encrasicolus, Trachurus mediterraneus, Sarda sarda, Belone belone, Pomatus saltatrix, Merlangius merlangus and Mullus barbatus. A total of 352 plastic particles were removed from 190 individuals (29% of all individuals examined). The mean number of plastic particles per fish was 0.81±1.42 par.ind-1 (considering all fish analysed, n=650) and 2.06±1.09 par.ind-1 (considering only the fish that ingested plastic, n=190). The most common types of plastics were fibres (68.5%), followed by films (19%), fragments (11.9%), foams (0.3 %) and microbeads (0.3%). The most common plastic colour was black (39.3%) followed by blue (19.5%) and transparent (18.1%). The length of plastics ranged from 0.05 to 26.5 mm with an average of 1.84±2.80 mm. 93.2% of plastics were microplastics, 6.5 % as mesoplastics and 0.3% macroplastics. Plastic occurrence was higher in S. sarda (plastic in 70% of the analysed individuals) and lower in M. merlangus (plastic in 9% of the analysed individuals). The main synthetic polymers identified by Fourier-transform infrared (FTIR) spectroscopy were polypropylene (29.8%), polyester (17.5%), acrylic (15.8%), polyethylene (14%) and polystyrene (1.8%) and 21.1% of polymers were cellulosic. Results show that commercial fish of the Black Sea is contaminated by plastics. This might affect vital functions of fish and pose a risk to ecosystem and human health. The study contributes to a better understanding of the status of plastic pollution in the fish from different habitats of the Black Sea and provides baseline data to implement the Marine Strategy Framework Directive in the basin.

Characterization and comparison of the digestive physiology of two scombrids, Katsuwonus pelamis and Sarda sarda, in the Gulf of Cádiz

Fish and other marine animals have a unique and intimate interaction with their surrounding environment. Diet type or trophic level play significant roles in modulating species digestive physiology. However, little is known about how the trophic niche influences digestive activity and gut microbiota in scombrids species. The aim of the present study was to analyse and describe the digestive physiology of the skipjack tuna (Katsuwonus pelamis) and the Atlantic bonito (Sarda sarda) as bioindicator of the feeding ecology and trophic niche for both species in the Gulf of Cádiz (Spain). For that, fish proximate composition, pH of digestive organs and digestive enzymes activity levels were analysed in 10 individuals of each species to gain insight into the digestive physiological adaptations of the two species of scombrids. In addition, intestinal microbiota composition was determined for the skipjack tuna. The integration of the results suggested a clear trophic niche segregation between both species. Stomach pH was associated in both species with infrequent feeding events. Body proximate composition and digestive lipases activity patterns pointed to a high predominance of lipids in the Atlantic bonito diet, suggesting oily fish as main prey. On the other hand, results supported the skipjack tuna as a highly opportunistic feeder with a more varied diet, including fish but also crustaceans as preys. The gut microbial community in the latter species is dominated by Firmicutes and Tenericutes at phylum level, and by Mycoplasma, Blautia and Dorea at genus level. The present study contributes to advance the knowledge on the feeding behaviour and physiology diversity in fish species as a result of adaptation to a particular habitat.

Isolation of Phaeobacter sp. from Larvae of Atlantic Bonito (Sarda sarda) in a Mesocosmos Unit, and Its Use for the Rearing of European Seabass Larvae (Dicentrarchus labrax L.)

The target of this study was to use indigenous probiotic bacteria in the rearing of seabass larvae. A Phaeobacter sp. strain isolated from bonito yolk-sac larvae (Sarda sarda) and identified by amplification of 16S rDNA showed in vitro inhibition against Vibrio anguillarum. This Phaeobacter sp. strain was used in the rearing of seabass larvae (Dicentrarchus labrax L.) in a large-scale trial. The survival of seabass after 60 days of rearing and the specific growth rate at the late exponential growth phase were significantly higher in the treatment receiving probiotics (p < 0.05). Microbial community richness as determined by denaturing gradient gel electrophoresis (DGGE) showed an increase in bacterial diversity with fish development. Changes associated with the administration of probiotics were observed 11 and 18 days after hatching but were not apparent after probiotic administration stopped. In a small challenge experiment, seabass larvae from probiotic treatment showed increased survival (p < 0.05) after experimental infection with a mild pathogen (Vibrio harveyi). Overall, our results showed that the use of an indigenous probiotic strain had a beneficial impact on larval rearing in industry-like conditions.

Trotline hook selectivity for the Atlantic Bonito (Sarda sarda Bloch, 1793) fishery in the Çanakkale Strait (northern Aegean Sea, Turkey)

This study was conducted to determine the selectivity of hooks (galvanized, tin, carbon, nickel) used for Atlantic bonito (Sarda sarda Bloch, 1793) in the Gallipoli Peninsula and the Dardanelles during the 2015 and 2018 fishing seasons (spring and autumn). The Atlantic bonito was fished with hooks of size 1/0, 2/0, 3/0, and 4/0. A total of 604 bonitos were caught, including 201 individuals using a galvanized hook, 194 individuals using a tin hook, 158 individuals using a nickel hook and 51 individuals using a carbon hook. A lower catch was obtained with hooks of size 4/0 (42 in total). The highest catch (100 total) was obtained with hooks of size 1/0 and a lower catch (19 in total) was obtained with hooks of size 4/0 in the case of tin hooks. In the case of nickel hooks, the highest catch (63 in total) was obtained with hooks of size 1/0 and a lower catch (eight in total) was obtained with hooks of size 4/0. The optimum catch length and curve width were calculated in relation to the size of hooks. It was determined that all hooks used in the experiments catch below the length allowed for fishing. It was therefore concluded that the use of the largest hooks would be preferable, with size 4/0 being the most suitable for maintaining the continuity of the species.