Teresa Bottari

Stock identification of Rajaclavata L. (Chondrichthyes, Rajidae) in two contiguous areas of the Mediterranean

The abundance, occurrence, biological features, growth and mortality parameters of the thornback ray, Raja clavata L. 1758 (Rajformes, Rajidae), coming from two contiguous areas of the Strait of Sicily (Central Mediterranean Sea) were analysed in order to discriminate the stocks. The two investigated areas include bottoms off southern Sicily (I-G16) and bottoms further at large (O-G16). The density indexes, biomass indexes and occurrences were substantially lower in I-G16 than O-G16. On the contrary, the biological traits were more similar, although significant differences were detected in the sex ratio, in the median total length of all specimens, in the length frequency distribution, in the estimated maximum length and in the female length-weight slope parameter. The median length of fully mature specimens did not significantly differ between the two areas. The von Bertalanffy’s asymptotic length and the ratio of total mortality/von Bertalanffy’s curvature parameter suggest a total mortality higher in the I-G16 than the O-G16 populations. This article supports the hypothesis that the investigated populations, in spite of a similar original life cycle, have evolved in two distinct unit stocks as a consequence of the different fishing efforts and the low-intermingling rate between the two areas.

Comparison of direct versus radiographic measurement of sagittal otoliths in cadavers of bogue (Boops boops)

OBJECTIVE To validate the use of radiography to determine the length of sagittal otoliths in intact bogue (Boops boops; a sparid fish [commonly called sea bream]). SAMPLE 52 bogue cadavers. PROCEDURES Weight and standard lengths (from the tip of the snout to the caudal end of the last vertebra) of fish were measured. The radiographic beam was centered over the postorbital area, and images were obtained via ventrodorsal, 30° right dorsal-left ventral oblique, and 30° left dorsal-right ventral oblique projections. Otoliths were removed from the fish; sagittae were measured directly and on radiographic images by use of a vernier caliper. The relationship between direct and radiographic measurements of sagittal otoliths was calculated. RESULTS Paired sagittal, lapillus, and asteriscus otoliths were identified. Sagittal otoliths were comma-shaped on ventrodorsal projections; in oblique projections, they appeared ovoid and pairs of otoliths were located in the same dorsal plane. Radiographic length of sagittal otoliths was significantly correlated with directly measured length, and radiographic measurements were not significantly different between ventrodorsal and oblique radiographic projections. CONCLUSIONS AND CLINICAL RELEVANCE Radiographic examination of sagittae was useful to determine the length of sagittal otoliths and, consequently, the fish length. In ecological applications, the radiographic measurement of sagittal otolith length may be useful for studies on the aquatic diet of organisms (fish, pinnipeds, and marine birds) because it allows for quick back-calculation to the size of prey.

Transplant Trials of the Fan Mussel Pinna nobilis Inside the Coastal Lagoon of Capo Peloro (Central Mediterranean, Italy)

ABSTRACT The fan mussel Pinna nobilis is threatened by several anthropogenic disturbances that are only partially mitigated by current conservation measures. In the Faro Lake Natural Reserve, the fan mussel population suffers from insufficient recruitment while, due to periodic dredging, a high larval supply within the canals does not support a stable population. In the present study, a robust number of fan mussel specimens were transplanted from a high-impact site to a guarded area to test the effects of transplantation on future conservation efforts. Over a 12-mo period, high survival and elevated growth were observed in the test population in comparison with the local population, demonstrating transplantation as a feasible and efficient method to prevent P. nobilis population decline. Such small-scale experiments provide useful indications for better management approaches for both of the threatened species and the natural hosting environment.

Anatomical evaluation of the organs in the red swamp crayfish, Procambarus clarkii, by diagnostic ultrasound examination

We describe the ultrasound examination of the cephalothorax and pleon in red swamp crayfish. Real-time B-mode, Color and Power Doppler examinations were performed on 10 crayfish, Procambarus clarkii (Girard, 1852). We envisage that use of this technique will provide baseline information for further imaging studies to investigate the cardiovascular and digestive physiology and can be applied to identify disorders in crayfish, to say nothing of use in other crustaceans.

Supplementation of Vitamins, Minerals, Enzymes and Antioxidants in Fish Feeds

The fast increase in marine aquaculture productions has generated some problems related to optimization of fish feed. Moreover, the search for alternative raw materials to supplement or replace fishmeal and fish oil has made the introduction of additives into the diet necessary. Diet additives have recently attracted attention and investments of the aquaculture industry and, consequently, researches aimed at evaluating the costs/benefits ratio and the effects on organisms and environments are increasing. In general, additives are nutritive or nonnutritive ingredients that are added to the diet alone or in combination with each other and that are present in small quantities. Their functions are different: preserve the physical and chemical features of the diet, enhance animal health and welfare, improve the quality of final product and maintain the quality of aquatic environment. This chapter provides an overview of the use of vitamins, minerals and antioxidants in fish feeds. In addition to these natural substances, also enzymes are proposed as new alternative aquafeed additives. The effects on fish growth, welfare, reproduction and health status of the above-reported additives are discussed.

Sustainable Alternatives for Dietary Fish Oil in Aquafeeds: Actual Situation and Future Perspectives

Fishmeal and fish oil have been for a long time the dominant raw materials for aquaculture feeds but these are limited and finite resources. Plant oils extracted from oilseeds are the main candidates as sustainable substitutes for fish oil in fish feeds and many studies have demonstrated the feasibility of their use. Plant oils are rich in linoleic and α-linolenic acids but lack in eicosapentaenoic and docosahexaenoic acids that belong to omega-3 long-chain polyunsaturated fatty acids and whose food consumption has been shown to have beneficial effects on human health. In the light of these considerations, it is clear that the most important problem of the replacement of dietary fish oil with plant oils is a reduction of the nutritional value of the flesh of farmed fish. This review attempts to provide an overview of the effects of the major plant lipid sources alternative to fish oil tested in studies carried out on farmed fish species.

Fishery Discard as a Source of Food for Reared or Wild Fish? The Bottom Trawling in the Mediterranean Sea as a Case Study

Fisheries products found in the landing places or markets usually represent a fraction of what has been originally taken out from the sea by fishermen. A more or less variable amount of the gross (or overall or initial) catch, in fact, is returned either dead or alive to the sea for multiple reasons. This phenomenon, generally known as ‘the discard problem’, has raised more and more global concern especially in the last decades since introducing more selectivity gears and acquiring more reliable catch data (also about the survival rate of the discarded specimens) are considered basic requirements in the current management plans for recovering and rebuilding fish stocks. To this concern, the current Common Fisheries Policy aims to reduce the discard rate in the European waters through the introduction of a landing obligation (better ‘discard ban’) according to which all the specimens of the ‘target’ stock caught must be landed. This chapter focuses on the characterization of the catch returned to the sea ‘potential’ available to be landed after the introduction of landing obligation, and the possible use as a potential food source in aquaculture (the direct use for human consumption is in fact prohibited).

Fishmeal Alternative Protein Sources for Aquaculture Feeds

Aquaculture currently accounts for approximately 50% of fish consumed by humans. The future development of aquaculture will be greatly constrained by the increasing costs of fishmeal and fish oil. To remedy this situation, scientific research and feed manufacturers have made a significant progress by looking for alternative protein sources for use in fish diets in order to develop feeds that provide adequate nutrition for animals’ growth, while reducing to minimum the use of traditional sources of protein. This chapter aims at critically reviewing recent studies, carried out worldwide, about the effects of the inclusion of new protein sources as insect, poultry by-products, meat and bone meals and other protein sources alternative to fishmeal in aquafeeds. In particular, the impacts of these protein sources in terms of growth, nutrient digestibility, fillet quality traits and sensorial perception in the most important farmed marine and freshwater fish species are evaluated.

Mass Mortality in Noah'S Ark Arca noae (Linnaeus, 1758): A Case Study from the Strait of Messina (Mediterranean Sea)

ABSTRACT Subtidal shell deposits of the edible bivalve Arca noae in the Strait of Messina (Central Mediterranean) were investigated and compared with an adjacent live population, testifying that dead and live populations were similar but distinct. The age–class structure of the two compared populations, whose lifespans ranged from 5 to 7 y, indicated that in this area unexploited Noahs ark stocks have generally low survival and recruitment. Shell morphometrics and size distributions suggested that the shell deposits were descriptive of the premortality population structure, as expected in a mass mortality episode.

New Host Records for the Marine Fish Ectoparasite Argulus vittatus (Crustacea: Branchiura: Argulidae)

ABSTRACT: The branchiuran parasite Argulus vittatus (Crustacea: Branchiura: Argulidae) was collected from the pectoral fin of the axillary bream Pagellus acarne, comber Serranus cabrilla, and greater amberjack Seriola dumerili from the northern coasts of Sicily (Mediterranean Sea), Italy. Pagellus acarne, Serranus cabrilla, and Seriola dumerili are new hosts for A. vittatus.