Marine Fungi from Central Pacific — Steele 
species per offshore sample in the Atlantic was 
6. In the Pacific the number ranged from 1 to 
11. Although the maximum number of species 
per Pacific sample exceeds that reported for the 
Atlantic, the total number of species found in 
each area is approximately the same: 133 species 
in the Atlantic compared with 127 in the Pa- 
cific. The diversity of genera is notably higher 
in the Pacific samples. Samples from both areas 
yielded fungi that were not identified. 
There are both differences and similarities 
between the kinds of fungi obtained from the 
two regions. A total of 30 species were common 
to Atlantic and Pacific waters. Neither Asco- 
mycetes nor Basidiomycetes were reported for 
the Atlantic. From the Pacific water 2 Ascomy- 
cetes and 1 Basidiomycete were recovered. Roth 
et al noted the low incidence of Phycomycetes, 
reporting only 6. Five species were identified in 
this Pacific study, but only 2 were from water 
samples. Species of Sphaeropsidales occurred in 
similar numbers in both oceans: 7 in the At- 
lantic and 5 in the Pacific, but only 2 species 
were common to both. In comparing the species 
of fungi which are predominant in each area, 
some species are found on both lists. Roth et al. 
distinguished 8 fungi each from the eulittoral 
and oceanic water samples as their dominant 
species. Of these, Aureohasidium pullulans was 
most common in the oceanic zone and it did not 
occur in their eulittoral list. In the Pacific, this 
fungus was common in water but ranked sev- 
enth among 18 species. Cladosporium species 
(sic) were the most common fungi in the At- 
lantic eulittoral samples, and occupied second 
place in the oceanic list. Two species, Clado- 
sporium cladosporioides and C. epiphyllum, 
ranked high among those frequent in both wa- 
ter and sand samples of the Pacific. Tricho- 
derma lignorum, the last species on the Atlantic 
list of eulittoral dominants, is absent from the 
corresponding oceanic list. In the Pacific it oc- 
curred in both water and sand samples, although 
much more frequently in water than in sand. 
In summary, the differences suggest that the 
Pacific fungus population is different from that 
of the Atlantic. 
Having established the fact that fungi can 
be isolated from Pacific as well as Atlantic 
water and shores, there still remains the prob- 
lem of how one determines whether or not a 
329 
certain isolate is a marine fungus. There is no 
single diagnostic test. The criteria which have 
been suggested are summarized by Roth et al. 
(1964) and may be stated as: (1) the isolate 
must grow and reproduce exclusively or pre- 
dominantly in the sea or on intertidal substrata, 
or (2) the isolate must grow and reproduce at 
an optimal level in the normal salinity of the 
oceans. None of these criteria can be supported 
without qualification. There is still no means of 
concrete demonstration of growth and repro- 
duction of a fungus in vivo in marine environ- 
ments except for those fungi growing on nat- 
ural (and introduced) substrata. If growth and 
reproduction at normal salinity levels is ac- 
cepted as a criterion, this allows for the inclu- 
sion of fungi found in salt lakes (Anastasiou, 
1963). Moreover, Gray (1963) has shown that 
many fungi of terrestrial origin are capable of 
better growth in sea water media than in fresh 
water media. If growth is limited to natural 
substrata, then the possibility of free-living ma- 
rine fungi is excluded. 
As more investigations of marine habitats 
are undertaken, the number of genera and spe- 
cies isolated from them will undoubtedly in- 
crease. Many of the genera found in the Pacific 
are known from other marine locations, e.g., 
species of Aureohasidium, Macrophoma, Phoma , 
Diplodina, Diplodia, Epicoccum, Fusidium, 
Cladosporium, Alternaria, and Macro sporium 
(Johnson and Sparrow, 1961). Repeated isola- 
tion, however, is not confirmatory evidence, but 
is only suggestive. Roth et al. (1964) contend 
that, until further distributional and physiolog- 
ical data are obtained, fungi so isolated should 
be regarded as of incidental occurrence in the 
sea. Nor is the rare isolation of a species from 
only marine habitats reliable evidence, as this 
may reflect only the randomness of the sam- 
pling and the samplers. Curiously, Dendry- 
phyiella arenaria Nicot, which is dominant in 
Atlantic eulittoral samples and known only 
from marine sources, was not among the Pa- 
cific isolates. Conversely, Botryophialophora 
marina, also known only from marine sources, 
was found in the Pacific but not in the Atlantic. 
In conclusion, a working definition for a 
marine fungus is proposed: A marine fungus 
is one which is capable of producing successive 
generations by sexual and/or asexual means in 
