Volume 9, Issue 4, April 2005
Volume 9, Issue 4 – April 2005
Acero, P., William J. Richards, Felipe Amaya and María M. Criales: First Caribbean record of Akko dionaea (Pisces: Gobiidae), another South American endemic , pp. 133-138
Akko dionaea Birdsong and Robins is reported here from the Colombian Caribbean, based on specimens collected at the mouth of the estuary Ciénaga Grande de Santa Marta. Ten night collections with channel nets at the mouth of the estuary yielded a total of 228 specimens representing larval to juvenile stages. Specimens were captured during the new and full moon, mainly during the dry season. Larval and juvenile stages of A. dionaea are described here for the first time. The species undergoes strong allometric changes during its development, mainly in the length of the head and eye. The species is described and the ecology and biogeography of the species are discussed.
Pre-flexion larval specimen of Akko dionaea from the Ciénaga Grande de Santa Marta: 4 mm SL Drawing by Jack Navech
Alexei M. Orlov: Bottom trawl-caught fishes and some features of their vertical distribution in the Pacific waters off the north Kuril Islands and south-east Kamchatka, 1993-1999, pp. 139-160
The species composition of demersal fishes in Pacific waters off the north Kuril Islands and south-east Kamchatka is considered. The study is based on 1275 demersal trawls carried out from 1993 to 1999 at depths between 76 and 833 m. The fishes identified in this study included 153 species, 97 genera, and 41 families; 62.1 % of the total were from the following families: snailfishes (Liparidae); sculpins (Cottidae); righteye flounders (Pleuronectidae); skates (Rajidae); eelpouts (Zoarcidae); rockfishes (Sebastidae) and poachers (Agonidae). The relative abundances of the 153 species collected were categorised as: Very rare: 79; Rare: 30; Common: 24; and Abundant: 20. Most species found off the north Kuril Islands and south-east Kamchatka were also common in the Sea of Okhotsk (74.5 %) and the western Bering Sea (80.4 %). The collected demersal fish species comprised: anadromous (1), neritic (3), mesopelagic (26), middle shelf (18), outer shelf (18), mesobenthic (62), and bathybenthic (25). Of the middle shelf species, the most abundant were northern rock sole Lepidopsetta polyxystra and Atka mackerel Pleurogrammus monopterygius. Atka mackerel Pleurogrammus monopterygius was also the most abundant fish in the outer shelf group. The mesobenthic fish fauna was dominated by the Alaska pollock Theragra chalcogramma, Pacific ocean perch Sebastes alutus, Atka mackerel Pleurogrammus monopterygius, and the northern rock sole, Lepidopsetta polyxystra. The most abundant bathybenthic fishes were the giant grenadier Albatrossia pectoralis, popeye grenadier Coryphae-noides cinereus, broadbanded thornyhead Sebastolobus macrochir, darkfin sculpin Malacocottus zonurus, and dimdisc snailfish Elassodiscus tremebundus.
Map of the study area, showing demersal trawl stations (hollow rectangles) in Pacific waters off the north Kuril Islands and south-east Kamchatka in 1993-1999. Thin lines and numbers indicate isobaths in meters
José Martins Silva-Jr, Flávio J. L. Silva and Ivan Sazima: Rest, nurture, sex, release, and play: diurnal underwater behaviour of the spinner dolphin at Fernando de Noronha Archipelago, SW Atlantic, pp. 161-176
No Arquipélago de Fernando de Noronha, Atlântico Sul Ocidental, golfinhos-rotadores (Stenella longirostris) congregam-se regularmente em grandes grupos numa baía rasa com água de boa visibilidade, o que permite sua observação a curta distância. Apresentamos aqui uma síntese sobre a atividade subaquática diurna dos rotadores de Noronha na baía. Ao lado de comportamentos bem conhecidos, como descanso, acasalamento e jogo, apresentamos e ilustramos alguns comportamentos pouco conhecidos e/ou documentados, como amamentar, defecar e vomitar. Interações e associações heteroespecíficas são também relatadas. Uma nova função ecológica para cetáceos, a de provedor de alimento para peixes recifais, é aqui proposta para os rotadores de Noronha.
A spinner dolphin voiding a cloud of particulate faeces. Note the sigmoid curve directed backwards formed by the hind-body on evacuation. Photo by J. M. Silva Jr