Prior to platform installation, baseline surveys were carried out in 2004 and 2005. The predominant fish species were whiting (Merlangius merlangus), haddock (Melanogramus aeglefinus), flatfish (mostly common dab, Limanda limanda) and hagfish (Myxine glutinosa) with no cod or saithe observed. Whereas maximum numbers (MaxN) of the three firsts species showed no statistical differences between the future area of the platform and the control site in 2005, after the construction (2007), there were larger numbers of Haddock, flatfish and hagfish and a decline in whiting maximum numbers. The MaxN of both whiting and flatfish was influenced by the light level but not current velocity. The effect of current speed on the MaxN of haddock (Melanogramus aeglefinus) was significant but collinear with the inter-annual effect and it was not possible to say which variable was causal. The MaxN of hagfish (Myxine glutinosa) was strongly related to current speed in a complex, non-linear way with a predicted upper current speed threshold above which MaxN declined.
Study of relationships between marine mammal and environmental variables in relation to fishing activity in Galician waters
Torres-Palenzuela J M 1, Santos-Diniz T.C2, Spyrakos E 1, & Pierce G.J3
1 Dep. Applied Physics. Science Faculty. University of Vigo. Lagoas Marcosende, 36310, Vigo, Spain
2 Instituto Español de Oceanografía.Centro Oceanográfico de Santander.Promontorio San Martín, s/n.39080 Santander.
3School of Biological Sciences (Zoology), University of Aberdeen, Tillydrone Avenue, Aberdeen AB24 2TZ – UK
This study related oceanographic and physiographic features to cetaceans’ diversity and abundance rates along Galician waters. Sea surface temperature and Chlorophyll-a concentrations estimated from space-borne remote sensors. A Geographic Information System (GIS) allowed the exploration and visualization of the nature of these relationships, and non-parametric statistics (Generalised Additive Models (GAMs)) were used to test the hypotheses generated by the GIS.