Technical problems of slowing the video playback speed and still maintain high resolution. Problems with tracking towed sleds accurately. Cannot reliably collect biomass data with video. Estimates can be generated by determining length of fish with laser dots and using length-weight relationship. Difficult to accurately identify taxa to the species level.
Poor resolution makes it necessary to lump several taxa together.
Sample area tends to be small and variable due to changes in visibility. Limitations of trawl Lack of exact information on where animals came from. Only get an average over the total area sampled. Difficult to follow a prior trawl track with a trawl in seabed impact studies. Trawl is ineffective at sampling the benthos.