Larval fish abundance and distribution during the late winter bloom off Gran Canaria Island, Canary Islands

Abstract

AbstractThe species composition, distribution and abundance of fish larvae off Gran Canaria (Canary Islands), an oceanic island in the NE Atlantic, were studied from January to August 2005. Weekly samplings were carried out at six stations in the eastern and southern flanks of the island, at the edge of the island shelf, in order to analyze the fluctuations of the planktonic community. The highest chlorophyll a values were recorded in March, coinciding with the lowest values of temperature in the mixed layer, which gave rise to the ‘late winter bloom’. Mesozooplankton biomass peaked with only a week‐lag to phytoplankton, and its average value (13.5 ± 10.9 SD mg dry weight m−3) was typical for the area. A clear windward‐leeward distribution pattern was found for small mesozooplankton and neritic larvae, showing higher values in two stagnation points, upstream and downstream of the island. A total of 128 taxa of fish larvae were identified. Neritic and oceanic larvae appeared in quite similar proportions. Only three families accounted for half of the total larval fish collected: Myctophidae (24.9%), Sparidae (12.7%) and Clupeidae (11.9%). Sardinella aurita (8% of total larvae collected) was the most abundant species, appearing during the whole period of study and at each of the six sampled stations. Sardina pilchardus larvae were rarely captured but were always encountered with the arrival of NW African upwelling filaments to the island coast, suggesting that these larvae were transported in those mesoscale structures.