Copepod profile

Two Batfish profiles of chlorophyll and copepods (sampled in the eastern Canadian Arctic) were separated by volume into their component species and are shown in Figure 5. The separation shows that both Calanus finmarchicus Stage V and Calanus glacialis Stage V are situated 5 m above the chlorophyll maximum, whereas Calanus hyperboreus Stages V and VI were situated primarily at or below the chlorophyll maximum. Such examples illustrate the species identification potential of the electronic counter and the resolution capabilities of the system for isolating species in the water column. 

Figure 5. Two Batfish profiles of copepods, chlorophyll, temperature, and salinity. The chlorophyll maximum is located at the base of the thermocline...

Zooplankton. Studies of the outer edge and shelf-break region of the Scotian Shelf were also extended to the vertical and horizontal distributions of zooplankton. The most intriguing feature of these vertical profiles was the consistent location of copepods above the subsurface chlorophyll... 

Eastern Canadian Arctic. In August 1980, ecological studies were conducted in Baffin Bay near the Greenland coast bounded by 75-76° N and 68-72° W. Figure 12 shows two typical profiles of temperature, salinity, chlorophyll, and total copepods from near surface to 100-m depth. The surface-mixed-layer depth extended to only 15 m with salinity values from 31.5 to 33.0 ppt, which indicate the influence of glacial runoff. The subsurface chlorophyll maximum was situated below a sharp thermocline that ranged from 1.0 to -1.5 °C. However, copepods were mainly situated above the chlorophyll maximum within the thermocline itself. 

Figure 10. Vertical Batfish profiles taken from the transect of Figure 6 on the Scotian Shelf. The profiles are separated into the following components chlorophyll, production estimated in two Ways from a chlorophyll/ light model, small copepods (S.C.), and all stages of C. finmarchicus (13).

Figure 11. The depth of maximum chlorophyll, production relative to small copepods, and C. finmarchicus. The tow began in coastal waters of the Scotian Shelf (left side of plot) and the course was reversed at the front. There are -- 90 vertical Batfish profiles in the transect (13).

Separation of the vertical interactions of copepods and chlorophyll requires a measurement resolution of — 1 m. Such a requirement was apparent in the Arctic data, which indicated small vertical separations of — 3-4 m between copepods and chlorophyll. Continuous profiling with the Batfish provides adequate statistical sampling of a large number of profiles... 

Figure 15. Copepod and chlorophyll profiles sampled at 1900 h (a) and the corresponding estimated production profiles (b) from the Peruvian shelf at 9° S. The vertical chlorophyll structure shows both a surface and subsurface...

The in situ Batfish sampler does not provide seawater samples for on-deck analysis. Therefore, we have also developed a continuous profiling pumping system (11) that measures biological profiles of copepods and chlorophyll and temperature while on station. Copepods and chlorophyll are measured on deck from the hose effluent with a deck-mounted electronic zooplankton counter and Turner 111 fluorometer. Measured profiles of copepods and chlorophyll indicate a vertical resolution of 3-4 m while the pumping system delivers — 50-60 L/min of seawater on deck. 

Although Anemia is well accepted and, when enriched, can produce good survival rates up to the first month of life, it does not have a suitable biochemical profile to meet the nutritional requirements of octopus larvae. This is very evident in relation to the level of PUFAS, particularly EPA and DHA (Navarro et al, 1992, 1993), which are found to be almost non-existent in newly hatched nauplii. Crustacean zoeae from the natural environment have a higher content of PUFA, particularly DHA (Navarro and Villanueva, 2000 Moxica et al, 2002). Other authors use frozen flakes of A. personatus (Okumura et al, 2005), cultured copepods Bersano (2003) or wild zooplankton (Estevez et al, 2009 Fuentes et a/., 2009) to provide an adequate nutritional profile. 

In light of the previous discussion on the hpid composition of both Anemia and rotifers, another major beneht of copepods as a food item for tuna larvae is their hpid profile. Like yolk sac larvae, copepods are dominated by polar hpids (8(L90 % of total hpid) and have both a high DHA concentration and high DFIA to EPA ratio (McKinnon et al, 2003). The... 

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