DOI: 10.3897/biorisk.17.77300

Authors: Albena Alexandrova, Yordan Raev, Dimitar Dimitrov, Nesho Chipev, Elina Tsvetanova, Almira Georgieva, Violin Raykov

Abstract: The aim of the present study was to perform a pilot assessment and analysis of the oxidative stress (OS) level in four commercially important fish species (round goby, red mullet, sprat and horse mackerel) from different localities of the Bulgarian Black Sea coast. The fish were sampled during trawl selectivity experiments. The OS level in the fish was assessed by measuring lipid peroxidation (LPO), glutathione concentration (GSH), activities of superoxide dismutase (SOD), catalase (CAT), glutathione peroxidase (GPx) and glutathione-S-transferase (GST), as well as acetylcholine esterase (AChE) in gills and liver. Round goby and red mullet caught in the Nessebar Bay showed clear signs of OS with the highest levels of LPO and GST activities, accompanied by the lowest AChE activities in both liver and gills. On the contrary, round goby caught near Maslen Nos (a region with good ecological conditions) were least affected by OS with low LPO and high GSH concentrations and SOD activity. There were no significant differences in the OS bioindicators of horse mackerel from the different localities. Sprat caught in Nessebar Bay, compared to those caught from the other localities, showed presence of OS indicated by lower GSH levels and relatively higher CAT, GPx and GST activities, accompanied by low AChE activity in gills. It can be concluded that round goby and red mullet were more vulnerable to OS induced by marine environmental factors than the horse mackerel and sprat. However, their antioxidant defense system allows them to tolerate and adapt to the environment of their habitats. Further studies are needed for the assessment of OS in important fish species in the Bulgarian part of the Black Sea.

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DOI: 10.3897/biorisk.3.11

Authors: Najah Hussain, Abdul-Razak Mohamed, Sajed Al Noor, Falah Mutlak, Ibrahim Abed, Brian Coad

Abstract: The aim of the present study is to determine the species composition, the structure of the fish assemblages, and to develop ecological indices in the restored east Al-Hammar Marsh. Fish were collected from October 2005 to September 2006 at two stations (Mansoury and Burkah). Fish samples contained freshwater species, both native and alien, and marine species. Thirty-one species were collected, eleven of them marine, the rest freshwater. Native species numbered 14 (45%), alien species 6 (19%) and marine species 11 (36%). Resident species formed 32.2%, seasonal species 16.0% and occasional species 51.6% of the fauna. The abundance of species varied, Liza abu being the most dominant species, with Carassius auratus ranking second and Acanthobrama marmid ranking third, comprising 35.8%, 23.6% and 10.6% respectively. Ecological indices were as follows: diversity ranged from 1.07 in November to 2.01 in July, richness ranged from 0.74 in December to 2.83 in July, and evenness ranged from 0.48 in November to 0.84 in December. The highest monthly similarity was in May at 77% and lowest in December at 29%. Water temperature showed medium correlations (0.62 and 0.58) with both the number of species and the total catch, respectively, while salinity exhibited weak positive correlations (0.05 and 0.26) with both the number and the total catch of species, respectively. Temperature is related to species number, presumably as a surrogate for many other seasonal changes.

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DOI: 10.3897/biorisk.3.15

Authors: Ibrahim Abed, Clayton Rubec, Brian Coad

Abstract: Surveys of fish in the southern marshes of Iraq are an integral component of the Key Biodiversity Areas (KBA) Project that was initiated in 2005 by Nature Iraq. This included sampling in the January to February and June periods of 2005, 2006 and 2007. Fish species occurrence, relative abundance, and weight and length were recorded. Species of importance for local consumption were noted. An initial project report included details and photographs of the species observed in 2005. Records based on interviews with local residents are noted. Sixteen “Species of Special Concern” are proposed, considering both economic and ecological factors that may be relevant to a future national fish management strategy in Iraq.

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