Novità faunistiche (Crustacea, Copepoda) da un ambiente salmastro costiero del Golfo di Taranto
Abstract
En
The artificial pond “Sette Nani” is a small, brackish basin on the Ionian coast of Apulia (southern Italy), about 50 km SE of Taranto. Its environmental (temperature, salinity, pH) and faunal characteristics were investigated (Ariani and Wittmann, 2014) in the frame of a study on ecology and breeding biology of the Mysida species Diamysis cymodoceae Wittmann and Ariani, 2012. These investigations revealed the presence of two copepod species: (1) the harpacticoid Tisbe tenera (G. O. Sars, 1905), and (2) the calanoid Calanipeda aquaedulcis Kriczaguin, 1873, first recorded here for the Ionian Sea and for the Ionian coast of the Italian peninsula, respectively. C. aquaedulcis is an invasive, essentially brackish-water element first described from the Ponto-Caspian basin and subsequently reported from several localities along the Mediterranean and the Eastern Atlantic coasts. Certain samplings of the species showed a sex-ratio near 1.0, indicative of potential genetic sex-determination, thus suggesting that the population components were born in the pond and developed there without apparent sexual selection. A sudden bloom of C. aquaedulcis was noted in January to March 2015, in accordance with the typical winter to early-spring maximum in this species, in this case coinciding with the massive appearance of a filiform green alga which quickly covered large parts of rock substrata: in fact, most fixed copepods were found inside the algal network, which they may have used for avoidance of predation. A population regression down to almost disappearance occurred in May, however followed by a further growth in August: the latter events may be explained in the light of the well-known production of resting eggs by C. aquaedulcis.
The artificial pond “Sette Nani” is a small, brackish basin on the Ionian coast of Apulia (southern Italy), about 50 km SE of Taranto. Its environmental (temperature, salinity, pH) and faunal characteristics were investigated (Ariani and Wittmann, 2014) in the frame of a study on ecology and breeding biology of the Mysida species Diamysis cymodoceae Wittmann and Ariani, 2012. These investigations revealed the presence of two copepod species: (1) the harpacticoid Tisbe tenera (G. O. Sars, 1905), and (2) the calanoid Calanipeda aquaedulcis Kriczaguin, 1873, first recorded here for the Ionian Sea and for the Ionian coast of the Italian peninsula, respectively. C. aquaedulcis is an invasive, essentially brackish-water element first described from the Ponto-Caspian basin and subsequently reported from several localities along the Mediterranean and the Eastern Atlantic coasts. Certain samplings of the species showed a sex-ratio near 1.0, indicative of potential genetic sex-determination, thus suggesting that the population components were born in the pond and developed there without apparent sexual selection. A sudden bloom of C. aquaedulcis was noted in January to March 2015, in accordance with the typical winter to early-spring maximum in this species, in this case coinciding with the massive appearance of a filiform green alga which quickly covered large parts of rock substrata: in fact, most fixed copepods were found inside the algal network, which they may have used for avoidance of predation. A population regression down to almost disappearance occurred in May, however followed by a further growth in August: the latter events may be explained in the light of the well-known production of resting eggs by C. aquaedulcis.
DOI Code:
10.1285/i15910725v37p3
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