Salpida species off the Catalan coast (NW Mediterranean) during summer 2003 and 2004. Neustonic and epipelagic planktonic sampling

Study Extent

The study was conducted along the Catalan coast in the NW Mediterranean.

Sampling

Three oceanographic cruises were conducted during summer of two consecutive years: 18–25 July 2003, 23-30 June 2004 and 21–29 July 2004. During each survey, 65-66 stations were sampled on transects perpendicular to the shoreline, over the continental shelf and slope. Stations on each transect were 14 km apart, while the distance between transects was 18.5 km. Zooplankton was sampled both near surface, in the neustonic layer (0-1.5 m depth), and in the first 200 m of the water column. In the first case a Neustonic net with 800 μm mesh size (mouth: 0.5 m x 1 m) was used while in the second one was a Bongo net with 60 cm mouth diameters and 300 μm mesh size. Zooplankton tows were carried out during day and night. Ship speed during tows was two knots. Neuston tows were horizontal while Bongo ones were oblique from a maximum depth of 200 m to the surface (or from 5 m above the bottom to the surface at stations shallower than 200 m). The volume of water filtered by the nets was estimated using a flowmeter suspended in the centre of each net mouth. Zooplankton samples were fixed immediately after collection in 5% formaldehyde buffered with sodium tetraborate. In the laboratory, all individuals of Salpida species were counted and identified to species level and also differentiated into their life stages (oozoid, bastozooid and embryo) using a stereomicroscope.

Method steps

1. Zooplankton sampling, samples fixed immediately after collection in 5% formaldehyde buffered with sodium tetraborate. In the laboratory, all individuals of Salpida species were counted and identified to species level and also differentiated into their life stages (oozoid, bastozooid and embryo) using a stereomicroscope.

All the species and life stages (oozoid, blastozoid and embryo) of the Order Salpida found during three oceanographic surveys, of mesoscale dimensions, carried out in July 2003 (an extremely warm summer), and in June and July 2004 (an average temperature summer).

1. Salpa maxima
   rank: species
2. Thalia democratica
   rank: species
3. Soestia zonaria
   rank: species
4. Thalia
   rank: genus
5. Animalia
   rank: kingdom
6. Chordata
   rank: phylum
7. Tunicata
   rank: subphylum
8. Thaliacea
   rank: class
9. Salpida
   rank: order
10. Salpidae
    rank: family

The Catalan coast in the NW Mediterranean.