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

Bio/consult as Page 19
• Wind direction
• Wind velocity
• Current direction
• Current velocity
3.6. Data processing
Information about the nets and related parameters along with catch results were entered
into Bio/consult’s database, FISKSYS. All parameters and results were geographically
oriented in relation to the Geographical Information System (GIS) Map Info.
Figure 3.6.1. Identification of some species were time consuming because of less morphological
differences between close related species. Pictures show identification of a longspined
bullhead (Left) and a short-spined sea scorpion (Right).
Catch Per Unit Effort (CPUE) for number and weight was calculated as the average
catch per sample for a given species at a given station.
In the fish study, one sample consisted of one pelagic gill net, one benthic gill net, one
turbot gill net, one standard fyke net and one fry fyke net.
In the fry study, one sample consisted of one standard fyke net and one fry fyke net.
The unit of effort was one night of fishing with the sampling units mentioned above.
Average values were calculated with regards to length, weight and condition factor. The
condition factor (CF) was calculated for every fish as:
CF = 100 · W/L 3
where W = the weight of the fish
L = the length of the fish
In addition, the average weight of gonads was recorded along with their stage of
development, broken down into five levels (the gonad index).
SEAS. Baseline study – Fish, fry and commercial fishery Dok. nr. 2148-03-001-rev3 2P.doc