Baseline study Fish, fry and commercial fishery Nysted Offshore ...

Bio/consult as Page 94
In biology similar grouping are most often used in examine plankton communities as
well as benthic invertebrate communities. In relation to fish, grouping has been used in
measuring energy flow through a system, by grouping into feeding guilds.
The species caught in this study have been grouped into six different descriptive groups
(Table 3.10.2). Some of the fish species occur in two groups if they fulfil the criterions
for both groups. The groups are made by viewing the biology of the species and to a
minor degree with respect to their trophic level. These groups have been used in both
the fish study and fry study.
Stationary species: Eelpout (Zoarces viviparous)
Short-spined sea scorpion (Myoxocephalus scorpius)
Longspined bullhead (Taurulus bubalis)
Hooknose (Agonus cataprachtus)
Sand lances: Small sandeel (Ammodytes tobianus)
Great sandeel (Hyperoplus lanceolatus)
Prey species: Sand goby (Pomatoschistus minutus)
Two-spotted goby (Gobiusculus flavescens)
Fifteen-spined stickleback (Spinachia spinachia)
Black goby (Gobius niger)
Pelagic species: Baltic herring (Clupea harengus)
Brisling (Sprattus sprattus)
Hornfish (Belone belone)
Commercial species: Turbot (Psetta maxima)
Atlantic cod (Gadus morhua)
Flounder (Platichthys flesus)
Reef species: Eelpout (Zoarces viviparous)
Common eel (Anguilla anguilla)
Atlantic cod (Gadus morhua)
Turbot (Psetta maxima)
Short-spined sea scorpius (Myoxocephalus scorpius)
Table 3.10.2. Fish species caught in the baseline studies classified into descriptive groups. Rare
occurring species are not included.
To evaluate the groups a power analysis was used. Results of the power analysis within
the groups are presented in Table 3.10.3. At least one individual from each group was
caught in at least 50% of sample efforts (One effort being: one pelagic, one benthic, one
fyke net and one fry fyke net.). The lowest values were obtained for the groups of sand
lances and the commercial species.
According to table 3.10.3 a power of 80% can be achieved if the number of sampling
stations are increased from 12 to 26 in each area. Since the variance between replicates
differ only slightly compared to differences between stations it is recommended to
redistribute the replicates into 12 new samplings stations and adding at least 2 new
sampling stations in each areas.
SEAS. Baseline study – Fish, fry and commercial fishery Dok. nr. 2148-03-001-rev3 2P.doc