Couto A.,University of Lisbon |
Couto A.,University of Porto |
Queiroz N.,University of Porto |
Relvas P.,University of Algarve |
And 8 more authors.
Marine Ecology Progress Series | Year: 2017
There is a general consensus that many shark species are declining in numbers. However, effective management measures often depend on knowing how trends in abundance and distribution are influenced by environmental conditions. Several efforts to describe the occurrence and distribution of basking sharks Cetorhinus maximus have been made in northern Europe, particularly around the UK, but nothing is known regarding their occurrence in southern areas, such as the south of Portugal. Using 2 decades of observational data collected in the south of Portugal, we show that the occurrence of basking sharks in the area was highly seasonal, with individuals being observed mainly during spring. Based on in situ and satellite-derived environmental variables and climate indices, we also demonstrate that temporal trends were associated with the beginning of the upwelling season and that the inter-annual changes were related to lower values of sea surface temperature, North Atlantic Oscillation index, upwelling index, 2-mo lagged chlorophyll a and 3-mo lagged Atlantic Multidecadal Oscillation index, and higher values of 2-mo lagged upwelling index. These findings suggest that basking sharks are associated with the expansion of cold waters following upwelling events in the region, probably due to the aggregation and increase of zooplankton. Although the temperature recorded during our study years ranged from 14 to 24°C, sharks were mainly observed when temperatures were lower than 20°C, corroborating their preference for colder water. This study provides the first knowledge on the habitat use of basking sharks in southern European Atlantic areas. © Inter-Research 2017.
Rodrigues N.V.,Polytechnic Institute of Leiria |
Correia J.P.S.,Polytechnic Institute of Leiria |
Graca J.T.C.,Tunipex |
Rodrigues F.,Tunipex |
And 2 more authors.
Journal of Fish Biology | Year: 2012
A whale shark Rhincodon typus was found in a set-net in southern Portugal in October 2011. This was the first record for continental Europe and represents an increase of the species' known range. Upwelling events and increase in sea-surface temperatures are possible reasons for this occurrence. © 2012 The Fisheries Society of the British Isles.
Rodrigues N.,Flying Sharks |
Correia J.,Flying Sharks |
Pinho R.,Flying Sharks |
Graca J.,Tunipex |
And 2 more authors.
Zoo Biology | Year: 2013
Bull rays (Pteromylaeus bovinus) and Dolphinfish (Coryphaena hippurus and Coryphaena equiselis) were collected in Olhão (south of Portugal). These animals hosted multiple parasites, namely Caligus spp., and underwent a variety of treatments to remove them. Of all treatments tested, hydrogen peroxide showed the best results, although only concentrations above 100 ppm were effective in parasite removal. These high concentrations, however, proved to be highly toxic for the fish and led to the loss of some animals, especially those which had been handled before treatment. A total of 14 Bull rays were transported to Bolougne-Sur-Mer (France) by road and some animals were lost, which was attributed to excessive time in transit (>45 hr). In another transport, three Bull rays and 10 Dolphinfishes were moved to Stralsund (Germany) by road and air. The mechanical wounds suffered by one of the Bull rays during transport led to its death and, consequently, a deterioration of water quality in the tank containing two other conspecifics. This deterioration of water quality resulted in problems for the other two Bull rays, and one perished approximately 48 hr after arrival. The authors concluded that Dolphinfish can be transported with a low bioload for at least 27 hr, and Bull rays should not undergo transports longer than 35 hr. Special attention must be taken to injured animals, since this can lead to a decrease in water quality and consequently affect other animals in the same transport tank. © 2012 Wiley Periodicals, Inc.
Correia J.P.,Flying Sharks |
Graca J.T.,Flying Sharks |
Hirofumi M.,Tunipex |
Kube N.,Deutsches Meeresmuseum
Zoo Biology | Year: 2011
During the second semester of 2009, three trips were made from Olhão (Southern Portugal) to Stralsund (Northern Germany) carrying 2.122 animals, which included multiple teleosts, elasmobranchs and invertebrates. This group included scombrids, such as 1.869 Scomber japonicus and 9 Sarda sarda, which are notoriously difficult to transport. However, multiple adaptations to transport regimes adopted regularly have allowed the authors to successfully move these animals by road and air over a total of up to 25hr. Such adaptations included maintaining oxygen saturation rates at approximately 200%, and also the constant addition of AmQuel ®, sodium bicarbonate, and sodium carbonate. Different formulations were used during the three trips, with the best results corresponding to 20/30/30ppm of the three aforementioned chemicals, respectively. The authors suggest, however, that a modified formula of 20/40/40ppm will allow for an even more stable pH on future trips. © 2010 Wiley-Liss, Inc..