The population biology, life history parameters and diet of the shorthead drum Larimus breviceps were assessed in Caraguatatuba Bight, a shallow non-estuarine environment. Two homogeneous areas, South and North, were selected, avoiding major sources of continental waters. Monthly from October 2003 to October 2004, three random samples were taken by trawling from 800 to 1600 m outward from the waterline. Larimus breviceps was the third most abundant species during the study period, and was considerably more abundant from February to May 2004. Smaller individuals were also more abundant during this period, which we therefore considered the main recruitment period of the species. The predominance of individuals of a limited size range (6–12 cm total length) seems to indicate that the area functions as a nursery for L. breviceps, sheltering late-juvenile individuals. This feature complicated the estimation of life history parameters, but by taking into account the peculiarities of the area and the identification of similar modal progressions during the sampling period, we obtained reasonable values for the parameterization of the von Bertalanffy Growth Model (L∞ = 32.25 cm, K = 0.72, tmax 4.38 y, Z = 12.104). The total mortality index does not reflect mortality rates only, but also the migration of older individuals to other, probably deeper, areas. The diet was based mainly on Crustacea, specifically Decapoda shrimps, with slight seasonal alterations.

The local population of common bottlenose dolphin in the Balearic Islands coastal waters, a mass tourism destination in the western Mediterranean subject to increasing anthropogenic pressures, was monitored over a three-year period. Photo-identification surveys provided a relatively small population estimate, even though the islands are considered to be a hotspot for the species in the Mediterranean. Dolphins showed strong site-fidelity and relatively limited mobility across the archipelago, which makes them highly dependent on waters which are severely affected by overfishing, habitat degradation and boat disturbance resulting from a continuously-growing tourism and shipping industry. Ecosystem-based management actions are urgently needed to ensure the conservation of this fragile population of bottlenose dolphins. Conservation measures should be developed within the already-existing political and legal marine biodiversity conservation framework and in collaboration with local authorities and stakeholders.

The genus Astrodia (Echinodermata: Ophiuroidea: Asteronychidae) was revised based on 34 specimens including two syntypes of Asteronyx excavata, two syntypes of Asteronyx plana and two syntypes of Ophiocreas abyssicola. We proposed a transfer of Ophiocreas abyssicola (Euryalidae) to the genus Astrodia. Consequently, Astrodia now includes four species, Astrodia abyssicola, A. excavata, A. plana and A. tenuispina. These four species are all redescribed. A taxonomic key to the species of the genus Astrodia is also provided.

The size selectivity of traditional gillnets for whiting, (Merlangius merlangus euxinus) was investigated in the eastern Black Sea between June 2010 and June 2011. Experimental fishing operations were carried out by using gillnets of 16, 17, 18, 20 and 22 mm mesh size. A total of 2038 specimens belonging to 16 different fish species were caught during the experiment. The Share Each Length's Catch Total method was used to fit gillnet selectivity curves. Gillnet selectivity was best described by a bi-modal selectivity curve. The modal catch sizes were estimated as 14.81, 15.74, 16.66, 18.51 and 20.37 cm for 16, 17, 18, 20 and 22 mm mesh sizes, respectively. Modal lengths and spread values increased with increasing mesh size. The majority of fish (71.8%) caught by 16 mm mesh size were less than the length at first sexual maturity.

Relations between fish size and otolith size of stargazer (Uranoscopus scaber) were studied in this study. A total of 268 samples were obtained from the coastal shelf of Ordu Province (south-eastern Black Sea) by commercial trawling and gillnetting operations. It was found that there were high correlations between fish size and otolith size. It was concluded that all measurable body sizes could be effectively used to estimate otolith length, width and weight. Similarly, estimation of the age of fish from otolith length and weight was also possible with high significance. The results of this research will be useful for others working on this fish, being a first study in the field. The ages of stargazer were determined between 0+ and 4+. Relationships were determined as OW = 0.001 × OWi2.76, OW = 0.35 × 10−3 × OL2.54 with high correlation coefficients of r = 0.965 and r = 0.949, respectively.

The forkbeard, Phycis phycis, is an important commercial species in Portugal; however, little information is available on its biology. Age and growth of the forkbeard from Portuguese continental waters were studied using 687 otoliths from specimens caught between May 2011 and December 2012. Otoliths were transversally sectioned, and assigned ages were validated by marginal increment analysis and edge analysis, and indices of precision were also calculated to corroborate ageing within and between readers. Validation techniques showed that an annual growth increment is formed every year, corresponding to the succession of an opaque and a translucent growth zone. Specimens ranged from 15.5 to 67.1 cm total length (TL), and their estimated ages ranged between 0 and 18 years. The forkbeard is a relatively slow growing, long lived species, that does not show sexual dimorphism in growth. The von Bertalanffy growth parameters estimated for forkbeard from the Portuguese continental waters were L∞ = 75.14 cm TL, k = 0.10 yr−1 and t0 = −2.09 yr.

Merluccius merluccius is an economically and ecologically important demersal species inhabiting the Atlantic Ocean and the Mediterranean Sea; however, reproductive knowledge about this species, along the North African coast is still missing. Monthly samples were collected from November 2010 to October 2011 along the North Tunisian coast. Morphometric parameters were measured, and histological preparations of gonadic tissues provided detailed information on the reproductive biology. Ovary maturity data showed a protracted spawning season throughout the year, with peaks in January, April and August. In females of M. merluccius, seasonal variability in weight and length were noticed, with higher values in the first part of the study period (November–April) than from May to October. Analysing separately these two periods, significant relationships were observed between gonadic maturation indices and the somatic and gonadic indices, suggesting a seasonal differential use of energy intake. From November to May the fish alternate the use of their energy for body growth and reserves for later uses (i.e fat, muscle and liver mass) or for gonadic growth. From June to October the energy is converted mainly into gonad weight and less to somatic growth. The maturity ogives obtained by macroscopic and histological maturity staging methods showed significant differences; however, in both cases the length at first maturity estimates were around 29 cm. Nonetheless, when selecting the main spawning period, the L50 estimation was heavily reduced to 24 cm, suggesting careful attention in the selection of the samples to be used specially for fishery management purposes.

As many Arctic fish species are intermediate hosts of anisakids, they are present in the diet of the ringed seal, Pusa hispida, and the bearded seal, Erignathus barbatus. Parasitic nematodes from the stomachs of 66 seals caught in the Nunavut region (Canada) from two communities (Arviat and Sanikiluaq) from October 2007 to January 2008 have been examined in order to identify the epidemiological risk for Inuit communities who consume traditional food. In Arviat 2428 anisakids were observed in 37 seals, while in Sanikiluaq 316 Anisakidae were isolated from 29 seals. The worms were treated with a host tissue, washed in deionized water and stored until analysis in 70% ethanol. The parasites were divided into three parts. The anterior and posterior parts were stored in 70% ethanol containing 5% glycerol and were examined using a light microscope by evaporation of the ethanol/glycerin mixture. The central parts were prepared for molecular identification by fixing in 70% ethanol. Using the polymerase chain reaction–restriction fragment length polymorphism (PCR–RFLP) method, the following members of the family Anisakidae were identified: Contracaecum osculatum A and C and Pseudoterranova bulbosa. In the studied material, more adult worms were noted than larval stages. The most numerous nematodes were P. bulbosa, and mixed infection was observed. The mean prevalence of anisakids infection was 43.2% in the Arviat and 37.9% in the Sanikiluaq communities.

Otolith microstructure analysis was used to determine daily growth rate and hatching periods of young of the year (YOY) annular seabream, Diplodus annularis, collected by using beach seine from Çanakkale shallow waters between January and December 2007. Total length of the YOY D. annularis was between 20 and 85 mm and the daily ages ranged between 27 and 205 d. Somatic growth rate, estimated by fitting a linear regression to the age–length data set, was calculated as 0.369 mm d−1. Seasonal changes in the growth rate of the YOY D. annularis have been found to be 0.381, 0.369, 0.357 and 0.308 mm d−1 for individuals that hatched in spring, summer, autumn and winter, respectively. Analysis of covariance indicated that there were no significant differences (P > 0.05) in the growth rates between the seasons. Hatching period of the YOY D. annularis was estimated to occur between March and September, with relatively higher hatching frequency in June.

The silver roughy, Hoplostethus mediterraneus is a benthopelagic cosmopolitan fish regularly caught as by-catch of the deep-water crustacean trawl fishery (CTF) in the central–eastern Mediterranean. Monthly samples of silver roughy were sampled from the catches of four commercial trawlers in 2004. Each trawler operated in different fishing grounds (FGs), located off Northern Tunisia, South of Sicily, Malta Islands and in South Levant, for which different exploitation levels are reported. The overall length–frequency distribution (LFD) was constructed, and fishing impact indices (length as percentage of LFD, optimum and maximum length, percentage of mega-spawners and total mortality/von Bertalanffy curvature ratio) were calculated. In spite of an overall acceptable status (juveniles, matures and mega-spawners were present in the catch), sampling data revealed significant differences in LFD shape and status indices between FGs. Those FGs traditionally considered more exploited (Northern Tunisia and South of Sicily) showed a dominance of juveniles, a rarefaction of mega-spawners, a reduction in maximum and asymptotic length and a higher Z/K ratio. Considering the general homogeneity of Mediterranean deep-water habitats, the pelagic dispersal of eggs and the poor swimming capabilities of silver roughy, the present results indicated that deep-water trawling may induce a slow and subtle, although significant, erosion of the older, late maturing and slow growing component of the stocks in the Mediterranean (so-called longevity-overfishing).

In Tunisia, elasmobranch landings have decreased substantially in recent years. Generally, species-specific information is largely unavailable for artisanal fisheries, but it is essential to increase knowledge and to ensure proper management of these species. This study analysed elasmobranch catches with longline fishery in the Gulf of Gabès. In total, 21 and 20 pelagic and bottom longline fishing trips were conducted, respectively, from July to September in 2007 and 2008. A total of eight elasmobranch species were caught: four batoids and four sharks. Pelagic longline captures were hooked externally while a high number of individuals captured with bottom longline were hooked internally. Discards due essentially to low commercial value and size represented 7.6% of total number of elasmobranch specimens caught. Longline landings in the Gulf of Gabès were principally composed of sandbar shark, Carcharhinus plumbeus, representing, respectively, 94.14% and 21.17% in number of pelagic and bottom longline captures. The importance of rhinobatids and Mustelus capture with bottom longline reflect their abundance in this area compared to other Mediterranean zones. Juveniles, including neonates with umbilical scars, dominated carcharhnids specimens, while smoothhound and guitarfish captures were dominated by mature individuals. Mitigation measures based on gear modifications, size limits and delineated nursery areas in the Gulf of Gabès should be developed to protect these vulnerable species.

The chub mackerel (Scomber japonicus) has been one of the important commercial pelagic species in the East China Sea since the decline of traditional demersal economic species. Although chub mackerel resources are suffering over-exploitation with the increase of fishing effort, their response to fishing and changing trends have not been analysed because of a shortage of data. In this paper we separated sample catches of chub mackerel from the central East China Sea during 2009 and 2010 into three age groups based on the age–fork length key. We then estimated the maximum sustainable yield (MSY) and built a spawner–recruitment relationship based on the fishery statistics of purse seine vessels, lighting purse seine vessels and deep-water purse seine vessels from 2006 to 2012. We predicted the biomass, spawning biomass, catches and the length compositions of catches when fishing at the current intensity (fishing mortality (F) = 0.7). The results showed that the MSY of chub mackerel is about 18.8 × 104t, and the fishing effort at MSY (EMSY) is about 72 standard purse seine vessels (both the lighting purse seine vessels and deep-water purse seine vessels were standardized to purse seine vessels), which is equivalent to F = 0.4. If F remains at the current level, the biomass of chub mackerel will remain at 45.3 × 104t. At the same time, more than 40% in the catch will be the individuals smaller than 200 mm, and only about 8% will be larger than 300 mm. Therefore, there is little potential for further exploitation of the chub mackerel resources in the central East China Sea, and it is better to reduce F to less than 0.4 for sustainable utilization.

This study aims to describe the spatial and temporal distribution patterns of Gobiidae larvae at a tropical estuarine system in south-east Brazil (Macaé). The samples were collected in six stations, through oblique hauls using a bongo net (330 µm mesh size), coupled to a flowmeter, during the night in the ebb and flood tides in March, July and October 2006 and in February 2007. In the Macaé River estuary was collected a total of 1,234 Gobiidae larvae, representing nine taxa. The highest densities occurred in the river mouth during the flood tide in the rainy season. The most abundant groups were: Gobiosoma parri, Gobionellus oceanicus and Ctenogobius boleosoma. Gobiosoma parri was also dominant at the Macaé estuary, which also presented higher densities in the coastal stations during the rainy season (March), both the flood as the ebb tide. Gobionellus oceanicus and Ctenogobius boleosoma were characteristic of the dry season in the mouth and river stations during the flood tide. The abiotic factors chlorophyll-a and temperature were considered biologically significant for Gobiidae larvae distribution. The spatial and seasonal variations together with the tide influence the distribution of the fish larvae Gobiidae family in the Macaé River estuary and its coastal zone.

Chromis chromis is one of the most abundant fish species on the Mediterranean rocky shores. Acting as a by-pass of nutrients from the pelagic to the rocky littoral system, it plays an important role as a resource provider and has a relevant function in the community assemblage. Chromis chromis has many of the characteristics required of an indicator species (e.g. it is easy to recognize in the field, small sized, widespread and abundant). In this study we focused on individual size, sex-ratio and body condition in a damselfish population occurring in a central Mediterranean marine protected area. Fishing trials on a monthly basis (April–November) allowed us to assess seasonal changes in population structure. Fish were measured and weighed and a subsample was aged and sexed. On average, males were larger than females. The allometric coefficient, b, for the whole population was 2.99; the maximum age recorded was 7.5 yr. Before reproduction sex-ratio was close to parity (M:F 1:0.78), while a larger proportion of females was captured during the reproductive period. In conclusion, our results show that the population dynamics of C. chromis is influenced by both sex and size. Since males and females have different behavioural strategies, and since the length of the spawning period is shorter in the smaller than in the larger-sized individuals, this is reflected in temporal changes observed in the population structure.