Eccezionale reperto di Nansenia oblita Facciola' 1887 ( pisces: Microstomatidae) catturato nel Golfo di Patti (ME)

Con la presente nota si da' notizia di un esemplare di eccezionali dimensioni di Nansenia oblita Facciola' 1887, rinvenuto nella primavera del 1991 tra il pescato di una rete a strascico convenzionalmante usata per la pesca del gambero bianco (Parapaenaeus longirostris) nel Golfo di Patti (ME) ad un profondita' di circa 400 metri. Vengono descritti i caratteri morfologici e cromatici

ANOTHER PECULIAR SITUATION FOR YOY OF BLUEFIN TUNA (THUNNUS THYNNUS) IN THE MEDITERRANEAN SEA IN 2016

The possible effects of the hottest temperatures recorded in 2016 (the hottest so far) on the bluefin tuna reproductive biology have been discussed by the SCRS in the past, but the situation in 2016 was very different. After collecting some detailed samples and data about the presence of YOY in various parts of the Mediterranean Sea, an unusual situation can be observed, showing different size-at-time by area in late summer-fall 2016, possibly mirroring early, late, fractioned and continued spawnings and different growth rates. These fish might result in future problems for age readings and ALK at least for the juveniles of bluefin tunas born in 2016. This paper provides the growth curves for the many cohorts of bluefin tuna YOY which have been detected and that were born in 2016

Spawning of bluefin tuna in the black sea: historical evidence, environmental constraints and population plasticity

<div><p>The lucrative and highly migratory Atlantic bluefin tuna, <em>Thunnus thynnus</em> (Linnaeus 1758<em>;</em> Scombridae), used to be distributed widely throughout the north Atlantic Ocean, Mediterranean Sea and Black Sea. Its migrations have supported sustainable fisheries and impacted local cultures since antiquity, but its biogeographic range has contracted since the 1950s. Most recently, the species disappeared from the Black Sea in the late 1980s and has not yet recovered. Reasons for the Black Sea disappearance, and the species-wide range contraction, are unclear. However bluefin tuna formerly foraged and possibly spawned in the Black Sea. Loss of a locally-reproducing population would represent a decline in population richness, and an increase in species vulnerability to perturbations such as exploitation and environmental change. Here we identify the main genetic and phenotypic adaptations that the population must have (had) in order to reproduce successfully in the specific hydrographic (estuarine) conditions of the Black Sea. By comparing hydrographic conditions in spawning areas of the three species of bluefin tunas, and applying a mechanistic model of egg buoyancy and sinking rate, we show that reproduction in the Black Sea must have required specific adaptations of egg buoyancy, fertilisation and development for reproductive success. Such adaptations by local populations of marine fish species spawning in estuarine areas are common as is evident from a meta-analysis of egg buoyancy data from 16 species of fish. We conclude that these adaptations would have been necessary for successful local reproduction by bluefin tuna in the Black Sea, and that a locally-adapted reproducing population may have disappeared. Recovery of bluefin tuna in the Black Sea, either for spawning or foraging, will occur fastest if any remaining locally adapted individuals are allowed to survive, and by conservation and recovery of depleted Mediterranean populations which could through time re-establish local Black Sea spawning and foraging.</p> </div

Sexual development, maturity and reproduction of dolphinfish (Coryphaena hippurus) in the western and central Mediterranean

Studies have been conducted on the sexual development, maturity and reproduction of the dolphinfish (Coryphaena hippurus L. 1758) in the Mediterranean area, with special reference to the Balearic islands and Sicily. Professional fishing, carried out from August to December 1996, uses FADs (Fish Attracting Devices) and surrounding nets. 2087 juvenile specimens of dolphinfish from the Ionian and southern Tyrrhenian seas, the Strait of Sicily and the Balearic islands were sampled. A small number of adult fish (39), which are not usually caught in surrounding nets, was sampled in the swordfish long-line by-catch. The gonads of the young fish were analysed monthly to establish the stage of development of the ovaries or testes, during the first few months of life. The gonads of the adult fish, sampled in the months of June-September only, were all mature. The specimens caught between October and December presented maturity stage V in the case of the females and I in the case of the males, indicating the end of the reproductive period. The gonado-somatic index (GSI) and condition factor (CF) were calculated for both genders. The trend of the GSI confirms the presence of immature specimens as regards the juvenile fish; the low value of GSI was obtained for the adults, probably associated with the post-reproduction conditions found in the October-December period. Most of the gonads sampled during the months between August and December belonged to young specimens born in early summer. This is confirmed by the juvenile stages (FL 2.5 to 4.3 cm) caught with plankton nets in the Strait of Messina area in July.No disponibl

Economic aspects of fishing of dolphinfish in Sicily

Dolphinfish fishing with Fish Aggregating Devices (FADs) and purseseine nets is normally practised everywhere in Sicily and the Pelagic Archipelago. The fishing season starts in July when the FADs are placed and finishes in December. In the 1996 fishing season, in 5 sample ports, catches and fishing effort were taken through interviews during landing, fishing running costs were taken by interviewing fishermen and prices per kilos paid to fishermen were taken through direct observation. Catches, costs and profits per sample port, per week and for the entire fishing season were then calculated or estimated. Though it is freshly marketed only in Sicily, the resource would appear to provide a lucrative activity.No disponibl

Sicilian dolphinfish (Coryphaena hippurus) fishery

In 1996, a census was taken of the Sicilian fisheries that engage in dolphinfish (Coryphaena hippurus L. 1758) fishing. Two different surveys were conducted; data on fishing boats were obtained from the Naval Registers and frominterviewing boat owners on the wharf. The area sampled was divided into 3 zones and 6 strata. 205 boats were recorded in the eastern zone (Tyrrhenian and Ionian seas), 57 boats located in 4 different strata were recorded in the western zone. Fishing activities in the Ionian area begin in early August and end in December. In all other areas of Sicily, dolphinfish fishing begins in early September and continues until December. A census was also taken of the equipment used by the various boats for this activity in the different areas. The surveys showed that FADs are the most commonly employed method for dolphinfish fishing. The geographical distribution, number and characteristics were recorded for each area surveyed. The catches for the 1996 fishing season distributed for strata and zone are reported.No disponibl