Zooplankton Fauna of Killary Harbour: the Seasonal Cycle of Abundance

Abstract

Killary Harbour is a fjord-like inlet on the west coast of Ireland and is an important site for suspended culture of mussels. As part of a study of the production ecology of the inlet, the zooplankton fauna was sampled quantitatively at two week intervals, between February 1981 and January 1982 using nets with mesh apertures of 90 and 335 μm. The dominant holozooplankton species of Killary Harbour are typical of inshore or neritic waters but there are also representatives of estuarine and oceanic faunas. Inflow of water into the bay below the surface layer of low salinity apparently maintains conditions suitable for neritic species and accounts for similarities between the zooplankton faunas inside and outside the bay. Large populations of estuarine species presumably do not develop because of the variability of freshwater discharge. During September 1981 there was evidence of an intrusion of oceanic water into the bay.

Variation in sea lice infestation on Atlantic salmon smolts in Killary Harbour, West Coast of Ireland

“…The species composition of the subsurface phytoplankton in the outer harbour was typical of coastal rather than estuarine water due to transport of these species by the landward-moving bottom current in this relatively deep area (Roden et al, 1987). Ryan et al (1986) also found that the zooplankton of Killary Harbour could be divided into two broad groups depending on their salinity preferences. Recent studies have shown that L. salmonis copepodids are found distributed within the top 6 m of the water body and that they migrate to the top 2 m during daylight (Heuch et al, in press).…”

A strategic simulation model of a fjord ecosystem

“…To test its success in this enterprise we require a reasonably spaced time series of data on the spatially averaged abundance of the three trophic levels we model, as well as free N inside the system and acceptable estimates of the external physical and biological influences on the system. Such data are not yet available for Loch Linnhe, but we have been able to assemble an acceptably complete data set for a fjordic inlet on the west coast of Ireland in 198 1 (McMahon and Patching 1984; Ryan et al 1986;Roden et al 1987;Rodhouse and Roden 1987). Killary Harbor is a shallow fjord with a maximum depth of 45 m, a mean depth of 14.5 m, and a total volume of -1.1 x 1 O8 m3 ).…”

“…Data on the species and numbers of herbivorous and gelatinous zooplankton are given by Ryan et al (1986) and converted to C concentration by Rodhouse and Roden (1987). We differ from these workers in using a C to dry weight conversion factor of 0.1 (rather than 0.2) for gelatinous zooplankton.…”

Histochemistry and histology in planktonic ecophysiological processes determination in a temperate estuary (Mondego River estuary, Portugal)

“…Available papers, concerning the interpretation of seasonal cycles, usually present a set of conclusions contemplating a complex conjunction of these factors (Castel and Courties, 1982;Davis, 1984;Deevey, 1971;Fulton, 1984;Gaughan and Potter, 1995;Herman et al, 1968;Mackas, 1992;Ryan et al, 1986), although only a limited number of them are identified as being primely responsible, being modelled, in a somewhat limited way, by the remaining others. In this situation, there are environmental parameters, such as temperature and salinity (Greenwood, 1981;Kouwenberg, 1994;Ladurantaye and Lacroix, 1980;Mallin, 1991;Tundisi, 1970;Wooldridge, 1986), nutrients (Gaughan and Potter, 1995;Herman et al, 1968) and hydrology (Castel and Courties, 1982;Mackas, 1992;Ryan et al, 1986).…”

“…In this situation, there are environmental parameters, such as temperature and salinity (Greenwood, 1981;Kouwenberg, 1994;Ladurantaye and Lacroix, 1980;Mallin, 1991;Tundisi, 1970;Wooldridge, 1986), nutrients (Gaughan and Potter, 1995;Herman et al, 1968) and hydrology (Castel and Courties, 1982;Mackas, 1992;Ryan et al, 1986). Regarding biological factors, citations range from food availability- (Deevey, 1971;Fulton, 1984;Herman et al, 1968;Ladurantaye and Lacroix, 1980;Mallin, 1991), predation and competition (Castel and Courties, 1982;Davis, 1984;Greenwood, 1981;Mackas, 1992;Morgado, 1993), growth rates (Fulton, 1984), mortality (Johnston and Nothcote, 1989) and behaviour sensu lato (Davis, 1984).…”