Fishery resources: between ecology and economy

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Spatio-temporal changes of Munida Rutllanti Zariquiey-Alvarez, 1952 (Decapoda: Galatheidae) in the North-Western Ionian Sea (Central Mediterranean)

The spatio-temporal pattern of Munida rutllanti distribution in the north-western Ionian Sea has been studied. Data were collected during 14 experimental trawl surveys conducted from 1997 to 2010 as part of the international MEDITS project. The hauls were carried out during day-light hours between depths of 10 and 800 m in the spring season. A progressive increase in the abundance index (N/km2) of M. rutllanti was observed from 2000 to 2008, then a sharp decrease was shown in the last two years. The greatest and lowest abundance indices were observed in the Apulian and central Calabrian sub-areas, respectively. The species was collected between 107 and 795 m in depth, with a significant increase and decrease over time in the maximum and minimum depth of finding, respectively. A highly significant increase over time in the mean carapace length was also observed in the whole study area. The widespread occurrence and increasing abundance of this species in the Ionian Sea could be related to the increase in temperature and the variation in hydrographic conditions which occurred in the Ionian basin during the EMT-BiOS phenomenon

IHTIOFAUNA MOČVARNOG EKOSUSTAVA BARDAČA (BOSNA I HERCEGOVINA)

The ichthyofauna composition of the wetland ecosystem in the Bardača area (Bosnia and Herzegovina) was described with the aim of indication on the richness and necessary protection of the biodiversity of this sensitive swamp region. During 2004, qualitative and quantitative fish samplings were carried out, according to seasons, in Matura and Brzaja rivers, the main tributaries of the drainage area around the Sava River. Fish samplings were carried out using an electro–generator pulse and removal method. Analysis of the sampled fishes consisted of species determination and estimation of yield for average density and biomass (N/m2 or m3 and g/m2 or m3). It could be said that during one year examinations, the presence of 24 fish species from 7 families has been determinate. In addition, the analysis of fish diversity was carried out by means of species richness, Shannon–Weaver index, evenness and Simpson index. According to analyzed data, it could be observed that 2 allochtonous pest species, Carassius auratus gibelio and Ictalurus nebulosus presents the most dominant fish species in these waters in almost all sampling seasons.U ovom je radu opisan sastav ihtiofaune močvarnog ekosustava Bardače (Bosna i Hercegovina), i to radi identifikacije bogatstva i prijeko potrebne zaštite biodiverziteta ove osjetljive močvarne regije. Tijekom godine 2004. izvršena je kvalitativno–kvantitativna analiza ribljeg naselja iz dviju rijeka, Mature i Brzaje, koje su pritoci rijeke Save na ovom području. Uzorkovanje riba provođeno je elektroagregatom za lov ribe, a izlovi su obavljani tijekom svih godišnjih doba. Analiza ulovljenih riba sastojala se od determinacije vrsta i proračuna njihove prosječne biomase i abundance (N/m2 ili m3 i g/m2 ili m3). Može se reći da je tijekom ovoga jednogodišnjeg ispitivanja utvrđena prisutnost 24 riblje vrste iz sedam porodica. Analiza diverziteta spomenutih ribljih vrsta utvrđena je računanjem sljedećih indeksa diverziteta: bogatstvo brojnosti vrsta (richness), Shannon–Weaverov indeksa, indeks ravnomjernosti distribucije vrsta (evenness) i Simpsonov indeks. Prema dobivenim podacima, zaključeno je da su dvije introducirane »korovske« vrste riba, Carassius auratus gibelio i Ictalurus nebulosus, bile najdominantnije vrste u ovim vodama, i to u gotovo svim godišnjim dobima

seafloor integrity of the mar piccolo basin southern italy quantifying anthropogenic impact

ABSTRACTThe Mar Piccolo Basin is a coastal brackish marine ecosystem located along the northern coast of the Gulf of Taranto (Southern Italy). Despite the ecological relevance of the area (Site of Community Importance IT9130004, Regional Reserve 'Palude La Vela' EUAP1189), the entire basin is subjected to intensive human usage. The main activities include extensive mussel farming, important industrial activities, a military harbor and densely populated shores. The goal of our study was to spatially quantify human pressure within the basin and its relationship with biocoenoses. A broad set of data was integrated including acoustic remote data (obtained using a multibeam echosounder and side scan sonar devices), direct observations obtained by SCUBA diving and from a trawled camera, an orthophoto and ESRI® Imagery Basemap. At least eight categories of anthropogenic infrastructure and marks of past and present-day human activities were identified within the Mar Piccolo Basin water column and on the seafloor...

Rhodolith Beds Heterogeneity along the Apulian Continental Shelf (Mediterranean Sea)

Rhodolith beds represent a key habitat worldwide, from tropical to polar ecosystems. Despite this habitat is considered a hotspot of biodiversity, providing a suite of ecosystem goods and services, still scarce quantitative information is available thus far about rhodolith beds occurrence and ecological role, especially in the Mediterranean Sea. This study reports the composition and patterns of distribution of rhodolith assemblages found in four study areas along ca. 860 km of coast in the Central Mediterranean Sea. These rhodolith beds were studied for the first time and significant differences at all spatial scales have been highlighted, documenting the high variability of this habitat. Rhodolith species composition, morphology and distribution have been discussed considering the potential role of environmental factors in driving these patterns. The need for improving their protection is discussed to complement present conservation and management initiatives, particularly in the frame of the EU Marine Strategy Framework Directive

Does the Bari Canyon (Central Mediterranean) influence the fish distribution and abundance

Abstract The objective of this study was to evaluate whether the Bari Canyon influences the distribution and abundance of fish fauna in the southern Adriatic Sea. Data were collected in the Bari Canyon and in an adjacent area on the continental slope during an experimental longline survey carried out in June 2015. A total of 19 fish species were collected (16 inside and 13 outside the canyon). Differences between the sites were evaluated by means of a set of univariate and multivariate methods (analysis of variance, permutational multivariate analysis of variance, non-metric multidimensional scaling). The abundance and biomass of the whole catch were significantly greater inside than outside the canyon. The most abundant species were the shark Galeus melastomus and the teleost fishes Conger conger, Helicolenus dactylopterus, Merluccius merluccius, Pagellus bogaraveo and Phycis blennoides. All these species were found to be more abundant in the canyon than in the adjacent area. However, a significantly greater abundance inside the canyon than outside was detected for C. conger, while P. blennoides showed both significantly greater abundance and biomass in the canyon than outside. P. bogaraveo was exclusively caught inside the canyon. C. conger and P. blennoides exhibited significant differences in their sizes between the canyon and the adjacent area: a greater number of both smaller and larger individuals were found in the canyon than on the open slope. Mature females and males were mostly observed in the canyon in all the most abundant species, with the exception of P. blennoides due to its autumn-winter spawning. The present study corroborates the role of the Bari Canyon as a refuge area and an Essential Fish Habitat for fish species exploited in the neighbouring fishing grounds, highlighting the need for conservation measures