one follows the food web from man through fishes one may eventually reach the
plankton of fresh- and brackish waters. Of the plankton organisms the
zooplanktons are important for many fishes, including some of the species that
are cultivated in ponds, pens and cages all over the Philippines (Aquino, 1982, Aquino et
1983, Fernando, 2002a, Hartmut, 2003, Nielsen,
1974, Papa, 2008a) -
just take a view over Laguna de Bay and bee convinced
in the food chain.
constitutes the main food of most fish species when these are at their young,
post-larval stage. Insects and other organisms from the littoral zone
supplement the zooplankton. Some fishes like the herbivorous cichlids switch
from being zooplanktivory to plant diet at a very early age (Fernando, 2002a).
. The invasive Mosquito fish, Gambusia
affinis, is widespread and common in canals, creeks, swamps,
ponds and shallow areas of lakes. It feeds on zooplanktons, small insects and
of the major reasons why larger fish abandon this food source is that it
becomes too small relative
to their body size and is too dispersed in the water to be profitable.
Practically the only way for larger fish to obtain sufficient quantities is by
filter feeding (e.g. bighead carp). Nevertheless, the larger plankters are
normally scarce in or absent from the diets of phytoplanktivorous fish such as
milkfish and tilapia. These fish move to slowly through the water when
filtering than zooplanktivorous fish do, allowing the larger plankton to
escape (Richter, 2001).
development thus partly depends on the availability of adequate zooplankton as
principal food items of early life history stages of economically important
fish species as well as of the adults of some species (Mamaril, 2001a). The
cultured bighead carp, Hypophthalmichthys nobilis (Richardson, 1845)
feed on zooplankton
mechanical filtering of the water through the gillrakers with an interrraker
distance of 60-100 µm, it is able to select
especially copepodits from the water in Laguna de Bay, shown by Petersen (1981e) and Santiago (2004). The
catadromous milkfish Chanos chanos (Forsskål,
1775), that breed in
the sea, feed on the abundant zooplankton there and then enter freshwater to
take advantage directly or indirectly of the year round food supply and the
high primary production (Gross et al. in Fernando, 2002a).
Lake Taal in Batangas the clupeid freshwater sardine Sardinella
tawilis (HERRE 1927) exhibit surface filter feeding with particulate
filtering capacity. Periodically it has a planktivorous diet of
zooplankton such as ostracods, cladocerans (Bosmina sp., Moina sp.,
Diaphanosoma sp., Ceriodaphnia sp. and Simocephalus sp.)
copepods (Cyclopoids and Calanoids), and rotifers (Brachionus spp.). In
a more recent study Bosmina sp. had the highest occurrence items in the
stomachs of tawilis purchased from the market.
“Tawilis” sold at the Binangonan Market.
Photo Flemming Petersen, 2013
Planktivorous fishes may
have a direct effect on these large zooplankton groups (Papa, 2008a,
Papa et al. 2011b)
and the cladocerans even almost eliminated by fish (Fernando, 2002a). The
freshwater sardine is thus an important example of the importance of
zooplankton as a trophic link between phytoplankton and fishes. Visually
guided planktivorous fish can thus exert strong predation pressure, which
zooplankton avoid by migrating downwards to a depth where low irradiance
prevents detection (Papa, 2008a,
of a food web in a lake. After Petersen 1981e
In at study
of vertical distribution during daylight, copepods with eggs where thus
primarily found near the bottom of the shallow, but turbid lake Laguna de Bay,
invisible for the zooplanktivorous fishes (Petersen, 1981e). The high predation from zooplanktivorous fishes and
fish-larvae, the competition from phytoplanktivorous fishes are reducing the
diversity of zooplankton of tropical freshwater (compared with temperate
waters), the size of zooplankton animals and the total biomass. As a
consequence the zooplankton of the tropical lakes does not control
phytoplankton biomass (Fernando, 2002a) as seen in many temperate lakes. In
the Danish Lake Esrom, Daphnia sp., which is rare in the tropical freshwaters,
controlled the phytoplankton-biomass in the warm summer period (Petersen,
Other factors can influence
the composition of zooplankton in a lake.
Other factors can influence
the composition of zooplankton in a lake. In general the zooplankton
community structure, population dynamics, and production are strongly
influenced by lake productivity, and zooplankton is of this reason a useful
indicator of eutrophication of lakes. (Papa et al. 2011b). Difference in
diversity and distribution of the zooplankton within a lake may be
influenced by anthropogenic eutrophication, like the 10.000 fish cages in the
Northern basin of Taal lake (Gulati
2009). Further weather conditions can have an impact on the zooplankton
distribution, this is especially the case for tropical zooplanktons, since
their relatively smaller size (Papa
et al. 2011b). Studies have shown that
physico-chemical parameters can
be correlated to zooplankton abundance, species number and diversity. The
study by the Papa and his group (Lazo, 2009) has revealed a moderate to
high correlation to rotifers population in Pasig River to the dissolved
oxygen in the river.
The most dominate zooplankton in Laguna
de Bay before 1980 was cladocerans followed by copepods and then rotifers.
This was about the time when the total fish pen area was at its maximum (ca.
30,000 ha). Declining zooplankton biomass has been marked between 1982 and
1983. The expanding fish pen industry, the operation of the Hydraulic Control
Structure (HCS) across the Napindan channel had become operational in
regulating the flow of water in and out of the lake via the Pasig River, and
lake pollution had separate adverse effects on the zooplankton. Shifts
in the structural features of zooplankton communities became apparent seven
year after the operation of the HCS, or 4 to 5 yr after the demolition of fish
pens. Copepods became dominant over the cladocerans and rotifers in that order
1983, Tamayo-Zafaralla et al., 2002).
is no doubt that zooplankton enters into the diet of different species and
stages of fish, but the role of Cladocera, Copepoda and Rotifera in the food
of these fishes is only recently being investigated. (Fernando, 2002a, Papa
2008a, Petersen, 1981e, Richter,
H. 2001, Santiago et al., 2004). It is the hope of the author that this key
will help in intensifying the research about this problem, finding the per
capita ration of zooplankton (and other animals) necessary for raising a fish
to recruitment stage in fishery or to fingerling stage for fish culture, as on
of the most important ways of getting more animal protein at less cost.
Zooplankton studies of
secondary production has been done in Laguna de Bay (Petersen 1981e, Nielsen
1983). These studies were a part of ecological investigations including
measurement of primary production and important physical and chemical
parameters and gave a further insight in the factors determining
the fish production, modifying the conclusions from the SOGREAH-report
(1974). As pointed out in Nielsen et al. (1981) and Nielsen (1981), the
limiting factors for fish production varied between inorganic turbidity
(November-May), self shading (May-August) and phosphorous (not nitrogen as
stated in the SOGREA-report (1974))
in September to October. The period of self shading
of phytoplankton, was the
period of high primary production, followed by a period of high biomass and
secondary production of zooplankton.
And a documented maximum in growth rate of Tilapia in fish pens from May to
August. The total annual primary production was
found to be 5 g*L-1*yr-1 (wet weight) giving raise to
a secondary production of zooplankton of 0.38 g*L-1*yr-1
(Divided by Rotifers: 17 %, Cladocera: 19 % and Copepods: 64 %).
In order to make decisions about
sustainable aquaculture management in the Philippine Freshwaters,
research projects like these,
has to be considered in the future.
productivity of plankton in a lake. Here Laguna de Bay 1980. (after Petersen
the earliest report of a Philippine rotifer zooplankton species (Semper, 1872,
1875), the first publications about systematics of about Philippine
are mainly written in the German language (Brehm 1933a, 1937, 1938, Kiefer 1928b,
1930a, 1939a, 1939b, Woltereck 1941a) and a few
in English (Marsh 1932, Wright 1928a, 1928c, 1937). Woltereck's paper
(1941a) is very extensive, including zooplankton as well as records of
phytoplankton, molluscs, some macro crustaceans, and fishes from major lakes
in the Philippines, together with Hydrobiological notes. Ueno (1966) included
further 6 species to the list from his collections in Luzon.
The first comprehensive papers are the studies
by Mamaril and Fernando (1978a,b, 1986a) who noted that there are around 125
species of freshwater zooplankton belonging to Rotifera, Cladocera and
Copepoda. Of the total, 61 species belong to Rotifera, 49 to Cladocera and 15
to Copepoda. Mamaril
's papers mainly describe species collected from the shorelines of the sampling localities. In this way of sampling, primarily
species found in ponds and the littoral zone of lakes have been recorded and
some pelagical zooplankton species was not included.
Laguna de Bay, Fish pens and Manila Skyline, 2013
Lai, Mamaril and Fernando (1979a) had revised the
freshwater calanoid copepods of the Philippines and created a new genus (Filipinodiaptomus)
for an endemic species of the Philippines. My
own studies revealed a few more records for the Philippines through a one-year
ecological study of Laguna de Bay, mainly (Petersen 1981e, Petersen and Carlos 1984a).
Korovchinsky (1913) review the research on Cladocera exploration of taxon
richness in the Philippines in the following matter:
“A more extensive, though rather routine, investigation was made on the
Cladocera of the Philippines, with 49 species recorded by Mamaril and
Fernando (1978).This survey was the last for these islands (for
cladocerans). The species list published later (Mamaril, 2001), fully
repeated the list from the previous publication. Other studies concerned
only individual water bodies (Papa et al., 2011, 2012).”
The paper by Pascual et al. (1914) implies that research on Cladocera is
still going strong.
The planktonic cyclopoid copepods of the Philippines has recently been
studied and revised by
Papa and Hołyńska (2013).
A new species was found in Lake Siliton (Mindanao) and named Mesocyclops
augusti, after the Philippine nestor of zooplankton studies: Augustus
Recently the Rotifers have
been further studied (Tuyor and Segers, 1999). In
a study by Berbano et al (2001c) 6 species of Rotifera, 8 species of
cladocerans and 6 species of copepods were found in Lake Taal where the
Keratella procurva, Diaphanosoma sarsi and Eucyclops "serrulatus"
were the most abundant rotifer, cladoceran and copepod, respectively.
The literature about Taal Lake has just been reviewed by Papa and Mamaril
and species composition updated by Papa et al. (2012b).
Further the composition, abundance and distribution in space and in time of
the rotifers of Pasig River has been investigated by Papa and his team (Lazo
et al, 2009a). Factors as dissolved oxygen, temperature and salinity affected
the abundance of the species, among which pollution tolerant and indicator
species from Brachionus (e.g. B. caudatus), Keratella (e.g. K.
tropica) and Filinia were among the most common rotifers. The
Philippine species of Diaphanosoma are investigated and revised by
Korovchinsky (1986, 1991, 1998a, 2000a+b)). The mainly marine Calanoid
copepods of the genus Pseudodiaptomus was studied by Walter (1986b)
and Walter et al (2006).
Very recently samples
of cladocerans collected from 86 freshwater ecosystems in 2006 to 2013 were
investigated with modern anatomical techniques revealed of 16 species.
Bosminids were mainly collected from the islands of Luzon and Mindanao,
rarely in the Visayans, while Sididae and Chydoridae were distributed
throughout the archipelago (Pascual et al. 2014).
writes about the characteristics of tropical zooplankton: “A contrast
between temperate and tropical Cladocera, Copepoda and Rotifera zooplankton
fauna shows a markedly different size composition and species diversity.
There are fewer species, and these are generally smaller in the tropics than
in either the North or South Temperate Zones. Larger species of the genera
Daphnia and Simocephalus are relatively rare [or absent] in
the tropics, while members of Eurycercus and Saycia are
absent. The genera Diaphanosoma
and Moina substitute these species in the limnetic niche in the
tropic waters of the Philippine like Taal Lake (Papa et al., 2012b).
Members of the families Holopedidae, Leptodoridae and Polyphemidae increase
in abundance toward the temperate regions. Two small cyclopoid copepods are
common in tropical zooplankton, while many of the common larger species of
other regions are absent or very rare. The chief rotifer components are
Keratella tropica and species of Brachionus.
Species of non-indigenous zooplankton like
havanaensis and Arctodiaptomus dorsalis have recently
been introduced to the Philippine lakes. One factor favoring this
introduction of invasive species is the introduction of aquacultures as seen
in Laguna de Bay and Lake Taal (Papa et al., 2012b) who states: “As the
under-regulated aquaculture practices and the introduction of alien [fish-]
species continue in many lakes in the archipelago, more alterations to the
native limnetic fauna may occur”.
Papa et al. discovered an invasion by the Neotropical Arctodiaptomus
dorsalis in 18 out of 27 lakes in the archipelago. Further they only
found four of the 12 previously recorded native and endemic calanoids in the
lakes. This may indicate a displacement by A. dorsalis eventually
boosted by a general deterioration of water quality of the lakes.
The aim of this
work is to give the researcher of the Philippines a key
is to overcome one of the
main constraints in doing ecological-aquaculture studies of zooplankton in the Philippine freshwaters
- the key literature for
determination of species.
of the key outside the Philippines shouldn’t be done isolated from keys for
the local areas (e.g.
Jose & Sanalkumar (2012).
A good supplement would be
The key will hopefully be useful in
zooplankton studies, which might be planned in ecological
and limnological studies in connection with
aquaculture. Although primarily a systematic paper, rather it is intended as a
handbook of the freshwater zooplankton
ecologist, and is though included some ecological
notes. For further reading se Fernando (2002a).
The key include information from the published
literature to which I have access to (see list of
literature) and personal observations about the
zooplankton done during own ecological studies in the
Philippines, primarily at SEAFDEC BRS in 1979-81
sponsored by the Danish Foreign Ministry, DANIDA-department.
The list of species of zooplankton in the Philippines
is still expanded with new records for the Philippines.
Further research will, without doubt, recover
more species to be added to the list. This
is said to warn against not being open-minded for the possibility of finding still unknown species of zooplankton for
the Philippines. In other words do not try to fit not described species
into the key. Some benthos species may also occasionally be sampled. See Fernando,
2002a for worldwide keys of tropical zooplankton.
Rey Donne S. Papa studying zooplankton in microscope.
in the key are more than 80 species of euzooplankton, holoplankton or
true zooplankton adapted to live in the limnetic or pelagic zone (Pelagic zone
refers to the free water mass in the sea and in lakes, while limnetic zone
refers to lakes only) of the lakes and those littoral forms, which are often
found among the euzooplankton as visitors or tychozooplankton.
The recent paper by Papa and Mamaril (2008c): Methods in Zooplankton
Sampling, Ecology and Identification for General Biology Teachers included
this paper; gives a review of the basic methods of sampling zooplankton
ecological studies of zooplankton a Sedgwick-Rafter counting chamber is a
must, or better (and more expensive) settling chambers used with an inverted
microscope. Only if very large species (e.g. Diaphanosoma) are studied, stereo
lupe will be sufficient in counting and measurements (Petersen 1983).
order to determine the species, the animals have to be studied under
microscope. Rotifers should be studied alive. They can be kept alive in a
refrigerator for considerable periods of time. Some species, however, can be
determined when preserved in 5% formalin (those with stiff shell). The
diagnosis of some species is based on the detailed structure of the trophi (jaws).
To study the trophi the specimen is irrigated with a dilute sodium
hypochlorite under a cover slip on a glass microscope slide. The other tissues
are dissolved away and the trophi can be conveniently studied.
cladocerans, which are transparent, can be studied without dissection, while
the copepods have to be dissected to determine the species. The 5th leg from
the adult copepod (male or female) is an important morphological character.
The use of the biological reagent “Polyvinyl Lactophenol” coloured red
with the biological stain Lignin Pink is often used for preparation of short time objects
Se Brandl (2002a) for more information about methodology.
At the University of Santo Thomas,
Manila, Rey D. S. Papa at the Research Center for the Natural and Applied
Sciences, has established
a Zooplankton reference Collection
from the Philippines. He and his students
are in a process of collecting from lakes,
rivers and other freshwater ecosystems and making systematic, and
ecological, studies of the
Philippine zooplankton, see UST (2013). The materials from these studies are
assembled in a special laboratory for this purpose.
analyse the data.
collection, counting etc. of the zooplankton, the data should be analysed
statistically. Papa et al (2011a) gives example of both simple at more
complicated methods of analysing the data. Here only two simple methods will
Sládeček (1983) found that the ratio between the number of species presents
of the genera Brachionus and Trichocerca (i.e. Brachionus: Trichocerca
quotient, QB/T) should be considered as an index of trophic
levels – since Brachionus species mainly are found in eutrophic waters,
while Trichocerca species prefer oligotrophic waters. The lake can thus be
oligotrophic when QB/T < 1,
mesotrophic when QB/T is between 1—2, and
eutrophic when QB/T > 2.
Papa et al (2011a)
found a QB/T of 7 in Taal Lake in 2008, clearly indicating the
lake as eutrophic.
Gannon & Stemberger (1978)
found that cladocerans and cyclopoid copepods are
more abundant (in numbers) in eutrophic lakes, while calanoid copepods
dominate oligotrophic lakes.
They found, from studies in the Great Lakes (North America), that a density
of calanoid copepods comprises over 50% of the crustacean zooplankton or a
ratio calanoids/ (cyclopoids + cladocerans) greater than 1 (QCal/(Cla+Cyc)
> 1) could be correlated with oligotrophy.
“But caution must
be exercised in establishing one-to-one causal relationships between
zooplankton composition and trophic conditions since other factors,
especially toxic pollutants and size-selective predation, may exert
considerable influence on changes in the community composition” (Gannon
Papa et al (2011a)
found a QCal/(Cla+Cyc)
< 0.5 in Taal lake, thus computed to quantify a zooplankton community
characteristic for the eutrophic status found of the lake.
to use the key.
The presented key is
ordinary "two-choose" (dichotomous) - rarely three-choose - key and
is arranged, as much as possible, systematically according to the literature.
The main morphological and some ecological information are included in the key.
It has to be said that most investigations of the ecology of zooplankton has
taken place outside the tropical region, and can only be applied tentatively
to the Philippine region. Exception is first of all the Lewis’ (1979) opus
on Lake Lanao zooplankton, a comprehensive analysis of the zooplankton
community of a tropical lake. It is advised as inspiration in the planning of
any ecological zooplankton study. Petersen (1981e) estimated secondary
productions of all major zooplanktons through one year in Laguna de Bay. Papa
et al. (2007a,
studied in a five-month
monitoring of Paoay Lake the
Impact of blooms of
the colonial green algae Botryococcus
braunii on the Zooplankton of Paoay Lake founding that both
the composition and the abundance of zooplankton in Paoay Lake were negatively affected by the occurrence of B.
The localities of occurrence are primarily only mentioned for major lakes of
the 59-70 Philippine lakes (Papa and
Mamaril, 2011a). A
figure of the location of some major Philippine freshwater lakes is modified
information can be found in the literature (Woltereck 1941a, Mamaril and
Fernando 1978b). The illustrations, following the key, are from two sources:
Firstly by copying from the literature by simple tracing technique (Flössner
1972, Kiefer 1978, Mamaril 1978a, Pontin 1978c, Ruttner-Kolisko 1972 (R-K))
and secondly from the original drawings by the author (1980, marked FP80).
The black bars in the illustrations equal 100 microns or 100 μm or 0.1 mm if no other measure is noted. Most of
the original drawings are copied in the same scale in order to give the "beginner"
in zooplankton studies a good chance to recognize the species and compare the
dimensions relatively to the other species found in the samples. In some
figures preserved specimens are included to show how they appear in fixed
condition (e.g. 76a) and some are shown at different
angles as might be observed in the counting chambers. Finally some photos are
added to the key to give a more visual impression of the animal as seen in the
microscope. These photos are all original photos.
The numbers in the key (la, lb, 2a, 2b, etc.) correspond to the numbers in the
illustrations. The key and the illustrations, therefore, can be crosschecked
The literature quoted in the key (after the species name)
is given only as year of publication.
To find the the reference it is necessary to find the author name in the chronological list of literature,
and there upon enter the alphabetical list of literature. The index gives key and illustration numbers for
all species and groups. It has to be noted that information about a species also can be found in the key for the
genera. The Internet can often give further information about the species – use the scientific
name as key words for the search.
The Binangonan Freshwater Research Station (SEAFDEC) at
Tapao Point, Binangonan, Rizal, has given me a good
opportunity to study the zooplankton populations in Laguna de Bay and
other lakes (se 1984a) and made me realize the importance of
zooplankton studies in aquaculture research.
of SEAFDEC Aquaculture Department) for
full-hearted support and to Mr. Andy Santiago
organization of the ecological/limnological teamwork. A special thank to Mr. Manuel Carlos for being a
and inspiring counterpart. Mr. H.
Segers (Belgium) for personal
correspondence about the Philippine rotifers.
Further thanks to following persons
involved in different ways of the publishing of the key:
Dr. J. B. Pantastico (SEAFDEC),
Director Roger S. V. Pullin (ICLARM),
Donne S. Papa (University of
Hanne Kamstrup, Mr. B
. H. Nielsen (Denmark), Ole
P. Udvang (Norway).
This edition has not been, if not for the interest, discussions and comments
Rey Donne S. Papa
(MS), a leading researcher in Philippine zooplankton, with a wide
international network being mentor for a new generation af zooplankton
Finally a very special thanks to
(University of the Philippines) for reviewing the manuscript
of the 1st edition of the key and for giving many
good and professional advices and suggestions. This work would not be
his great expertise on what he calls "the
beasts" of the Philippine Lakes. They are
Augustus Mamaril, Sr.
Rey Donne S. Papa –2008
May 1979 - Philippines