Biological Invasions of Cold-Water Coastal Ecosystems - Aquatic ...

Chapt 3. Biological Characteristics of Ballast Water, page 3- 12
Figure 3.3. Densities of organisms in ballast water arriving to Port Valdez for each source port. The
estimated mean densities (#/m³ and standard errors) are shown for all organisms by source port. The data include all
sample dates (sample size indicated above bars) but exclude chain-forming diatoms. Source ports include: Puget
Sound, WA (PS); San Francisco Bay, CA (SF); Long Beach, CA (LB); Foreign port with open-ocean exchange
(EX); Columbia River, Oregon (OR); and Barbers Point, Hawaii (HI).
DENSITY (#m³)
1.E+05
1.E+04
1.E+03
1.E+02
1.E+01
48
50
46 19 2
4
1.E+00
PS SF LB EX OR HI
SOURCE
The average total densities among domestic source ports corresponded to voyage
duration, with densities decreasing with voyage duration (see Fig. 2.7 of Chapt 2). Arrivals from
Puget Sound and San Francisco Bay had the shortest voyage duration (average of 4.3 and 6.0
days, respectively) and highest densities. Tankers arriving from Hawaii had the longest voyage
duration (average of 10.2 days) and lowest densities, whereas arrivals from Oregon and Long
Beach were intermediate to the other domestic ports in both respects.
(b) Density by Taxonomic Group and Source
All ballast water samples contained living organisms, but the prevalence and density
varied among taxonomic groups (Table 3.1). Copepods and diatoms were detected in ballast
water from 100% of the ships sampled, and protozoans (primarily tintinnids) were found in
nearly all samples. These three groups also exhibited the highest densities, dominating the
plankton community in ballast water (see below).
As with the total density measures, most taxonomic groups also occurred at greater
average densities in ballast water from domestic sources, when pooled, compared to that from
foreign sources (Table 3.1 and Fig 3.4). For most groups, this difference was 10- to 100-fold.
The magnitude of density differences between domestic and foreign sources were much less for
crustaceans, primarily due to the presence of copepods (see Table 3.1) and solitary diatoms.
Dinoflagellates were a notable exception to the general pattern, as average density was greatest
in ballast water of the foreign arrivals.