An update on the feeding habits of fish in the Mediterranean Sea (2002-2015)

In this study we updated the previous compilation of the feeding habits and trophic levels (TROPHs) of Mediterranean fish. In total, 172 publications were retrieved and analysed. Collected data refer to 146 species, with a TROPH value ranging from 2.00 to 4.54. The analysis of TROPH distribution verified the previously proposed classification of species into functional trophic groups. Overall, information on diet composition exits for 203 fish species out of the >700 fishes from the Mediterranean, a fact clearly showing that feeding habits are understudied despite their importance in ecological applications and fisheries management. More than half (60.6%) of these species are classified as omnivores with preference to animal material, 36.5% are carnivores, 1.9% are omnivores with preference to plants, and two (i.e. Siganus luridus and S. rivulatus) are pure herbivores. Finally, towards the direction of filling in information gaps, recommendations for future research are given

Feeding and ecomorphology of three clupeoids in the N Aegean Sea

The present study examines the feeding habits of anchovy (Engraulis encrasicolus), sardine (Sardina pilchardus) and round sardinella (Sardinella aurita). The results are combined with previously published information on feeding-related morphological features (i.e. mouth area, intestine length and tail area) in order to explore morphological affinities between species and the effect of ecomorphology on their co-existence. These species were mainly zooplanktivorous and no dietary differences were found with sex and season. Anchovy preyed mainly on Crustacea larvae, whereas sardine and round sardinella on Copepoda. In the majority of cases (>90%), the individual fractional trophic level of all species ranged between 3.0 and 3.5, classifying them as omnivores with preference to animals. The feeding-related morphological features differed between anchovy and the two other species, whereas only intestine length differed between sardine and round sardinella. The fact that round sardinella’s diet and morphology show a greater resemblance to those of sardine, further support the hypothesis that is a particulate feeder as sardine. Hence the three species tend to exploit the same food resources differently throughout the year. Thus, they make best use of the environment and its resources, in order to avoid competition and achieve optimum feeding conditions throughout their life cycle

What’s on the (publication fee) menu, who pays the bill and what should be the venue?

We address the cost of access to knowledge and its ethical implications in ‘true’, ‘pseudo’ and ‘hybrid’ OA journals

Age at maturity of Mediterranean marine fishes

In this review we collected data on the age at maturity (tm) and maximum reported age (tmax) for 235 stocks of Mediterranean marine fishes, belonging to 82 species, 37 families, 12 orders and 2 classes (Actinopterygii and Elasmobranchii). Among Actinopterygii (mean tm ± SD = 2.20 ± 1.43 y, n = 215), tm ranged from 0.3 y, for the common goby Pomatoschistus microps, to 12 y, for dusky grouper Epinephelus marginatus, while among Elasmobranchii (mean tm ± SD = 5.94 ± 2.47 y, n = 20), tm ranged between 2.7 y, for brown ray Raja miraletus, and 12 y for picked dogfish Squalus acanthias. Overall, the tmax ranged between 1 y, for transparent goby Aphia minuta, and 70 y, for wreckfish Polyprion americanus. The mean tmax of Actinopterygii (tmax ± SD = 10.14 ± 9.42 y) was lower than that of Elasmobranchii (tmax ± SD = 14.05 ± 8.47 y). The tm exhibited a strong positive linear relation with tmax for both Actinopterygii (logtm = 0.58 ´ logtmax – 0.25, r2 = 0.51, P < 0.001) and Elasmobranchii (logtm = 0.67 ´ logtmax – 0.006, r2 = 0.51, P = 0.007). The mean tm/tmax did not differ significantly with sex within Actinopterygii (ANOVA: F = 0.27, P = 0.60, n = 90; females: mean ± SD = 0.276 ± 0.143; males: mean ± SD = 0.265 ± 0.138) and Elasmobranchii (ANOVA: F = 1.44, P = 0.25, n = 10; females: mean ± SD = 0.499 ± 0.166; males: mean ± SD = 0.418 ± 0.133). Finally, the dimensionless ratio tm/tmax was significantly lower (ANOVA: F = 31.04, P < 0.001) for Actinopterygii (mean ± SD = 0.270 ± 0.135, n = 180) than for Elasmobranchii, (mean ± SD = 0.458 ± 0.152, n = 20), when stocks with combined sexes were excluded from the analysis

Prehrana i hranilišta traglja Spicara maena i gire S. smaris (Pisces, Osteichthyes, Centracanthidae) u sjevernom dijelu Egejskog mora

n the present paper we studied the diet of two centracanthid species , Spicara maena and S. smaris,in the N Aegean Sea. Overall, 282 and 118 individuals were examined, respectively. Both species preyed upon zooplankton, notably Copepoda (54.3 and 63.5%, respectively). S. maena included in its diet a wider variety of food items (36 taxa) compared to S. smaris (12 taxa). The individual trophic levels for both species ranged from 3.00 to 4.50 (mean values ± strandard error: 3.21±0.058 for S. maena and 3.05±0.068 for S. smaris ). Given their trophic position and local abundance, they play a crucial role in the flux of energy from low to high trophic levels of the Aegean benthic and pelagic food webs.U ovom radu prikazani su rezultati istraživanja prehrane dviju vrsta iz porodice girovki, traglja Spicara maenai gire S. smaris, sa sjevernog područja egejskog mora. Istraženo je 282 jedinki traglja te 118 jedinki gire. Obje vrste u svojoj prehrani koriste zooplankto, osobito veslonošcec opepoda (54.3% tragalj, 63.5% gira). Tragalj u svojoj prehrani koristi znatno širi raspon organizama (36 svojti) dok gira znatno manje (12 svojti). Pojedinačna trofička razina za obje vrste se kreće od 3.00 do 4.50 (srednja ijednost±standardna pogreška: 3.21±0.058 za traglja i 3.05±0.068 za giru).glede njihove trofičke razine i lokalne brojnosti, obje vrste igraju značajnu ulogu u protoku energije od najnižih do najviših trofičkih razina u e gejskom moru u okviru pelagijskog i bentoskog lanca prehrane

Editorial note on weight–length relations of fishes

Weight-length relations of fishes are useful for estimation of biomass from length observations, e.g., in fisheries or conservation research. Here we provide some guidance to authors of such papers, in order to facilitate the publication and review process

Editorial note on reproductive biology of fishes

Fish reproductive biology (onset and duration of spawning, sex ratio, maturity stages, length and age at maturity, and fecundity) is important in fisheries research, stock assessment, and management. In this editorial note, we provide some criteria and recommendations on issues of fish reproductive biology, which may be useful in research planning, data analysis and presentation, as well as in manuscript preparation

Biomechanics (Chapter 9)

Biomechanics is a discipline. A discipline deals with understanding, predicting, and explaining phenomena within a content domain, and biomechanics is the study of the human body in motion. Kinesiology, the parent discipline of biomechanics, is a science that investigates movement. Biomechanical research in human development focuses on evaluating essential movement patterns across the human life span. Biomechanical analysis is specifically important in quantifying the developmental motor skills and movement patterns such as walking, kicking, jumping, throwing, and catching. Biomechanical research also involves studying the movement patterns of injured and disabled people. Forensic biomechanists are invited to analyze evidence, clarify some of the most important issues, and facilitate the decisions of the jury. Motion recording devices use optical lenses to capture body motion and provide permanent recorded images of movement that can be evaluated with more precision than perception with the naked eye alone

Trammel net catch species composition, catch rates and metiers in southern European waters: A multivariate approach

We identified and quantified the effect of season, depth, and inner and outer panel mesh size on the trammel net catch species composition and catch rates in four southern European areas (Northeast Atlantic: Basque Country, Spain; Algarve, Portugal; Gulf of Cadiz, Spain; Mediterranean: Cyclades, Greece), all of which are characterised by important trammel net fisheries. In each area, we conducted, in 1999-2000, seasonal, experimental fishing trials at various depths with trammel nets of six different inner/outer panel mesh combinations (i.e., two large outer panel meshes and three small inner panel meshes). Overall, our study covered some of the most commonly used inner panel mesh sizes, ranging from 40 to 140 mm (stretched). We analysed the species composition and catch rates of the different inner/outer panel combinations with regression, multivariate analysis (cluster analysis and multidimensional scaling) and other 'community' techniques (number of species, dominance curves). All our analyses indicated that the outer panel mesh sizes used in the present study did not significantly affect the catch characteristics in terms of number of species, catch rates and species composition. Multivariate analyses and seasonal dominance plots indicated that in Basque, Algarve and Cyclades waters, where sampling covered wide depth ranges, both season and depth strongly affected catch species compositions. For the Gulf of Cadiz, where sampling was restricted to depths 10-30 m, season was the only factor affecting catch species composition and thus group formation. In contrast, the inner panel mesh size did not generally affect multidimensional group formation in all areas but affected the dominance of the species caught in the Algarve and the Gulf of Cadiz. Multivariate analyses also revealed 11 different metiers (i.e., season-depth-species-inner panel mesh size combinations) in the four areas. This clearly indicated the existence of trammel net 'hot spots', which represent essential habitats (e.g., spawning, nursery or wintering grounds) of the life history of the targeted and associated species. The number of specimens caught declined significantly with inner panel mesh size in all areas. We attributed this to the exponential decline in abundance with size, both within- and between-species. In contrast, the number of species caught in each area was not related to the inner mesh size. This was unexpected and might be a consequence of the wide size-selective range of trammel nets. (c) 2006 Elsevier B.V All rights reserved