Title: Zooplankton, fish communities and the role of planktivory in nine Ethiopian lakes

Journal: Hydrobiologia

Jacobus Vijverberg1,*, Eshete Dejen2, 3, Abebe Getahun4 and Leopold A.J. Nagelkerke5

1Netherlands Institute of Ecology (NIOO-KNAW), Droevendaalsesteeg 10, 6708 PB Wageningen, the Netherlands.

2Amhara Region Agricultural Research Institute, P.O. Box 527, Bahir Dar, Ethiopia.

3Present address: FAO, Sub Regional Office for Eastern Africa, P.O. Box 5536, Addis Ababa, Ethiopia.

4Department of Zoological Sciences, Addis Ababa University, P.O. Box 1176, Addis Ababa, Ethiopia.

5Wageningen University, Aquaculture and Fisheries Group, Wageningen Institute of Animal Sciences (WIAS), De Elst 1, 6708 WD Wageningen, the Netherlands

*) Corresponding author; e-mail:

Online Resource 1

Description

Additional background information on zooplankton and zooplanktivorous fish species from Ethiopia.

Tables 1, 2 and 3

Table 1 Length-weight relationships of zooplankton taxa used for the calculation of biomass of zooplankton in the environment. The length-weight relationship is W=a · Lb , where L is the length of the zooplankter in mm, and W is the individual carbon weight in µg. *= measured in dry weight and converted by the present authors in carbon weight assuming carbon weight 50 % of dry weight

Taxon
Present study / Taxon
Length-Weight est. / a / b / Reference
Bosmina longirostris / B. longirostris* / 3.93 / 1.79 / Culver et al., 1985
Ceriodaphnia spp. / C. cornuta / 0.93 / 1.21 / Amarasinghe et al., 1997
Diaphanosoma spp. / D. excisum / 0.71 / 1.34 / Amarasinghe et al., 1997
Daphnia hyalina
Daphnia barbata / D. galeata* / 4.47 / 2.03 / Culver et al., 1985
Daphnia magna / D. magna* / 3.115 / 2.785 / Bottrell et al., 1976
Moina micrura / M. micrura / 1.21 / 2.70 / Amarasinghe et al., 1997
Calanoid copepodites / Calanoid copepodites / 3.36 / 1.69 / Amarasinghe et al., 1997
Cyclopoid copepodites / Cyclopoid copepodites / 1.50 / 1.85 / Amarasinghe et al., 1997

Table 2 List of zooplankton species with maximum length (mm) and lakes where they were collected. Samples were taken in the open water zone in the period November 2004 to January 2005. For abbreviations of Lakes see Table 1, * = temperate species

Species/Taxa / Max. length (mm) / Lakes
CLADOCERANS
Bosmina longirostris (O.F. Müller)* / 0.4 / TA, KO
Ceriodaphnia cornuta Sars / 0.5 / TA, KO, ZW, AW, AB, CH
Ceriodaphnia dubia Richard* / 1.0 / AS, HA, TA, AB
Daphnia barbata Weltner / 1.5 / KO, ZW, LG, AB, CH
Daphnia hyalina Leydig* / 1.2 / TA
Daphnia magna Straus* / 2.9 / AS, HA, CH
Diaphanosoma excisum Sars / 1.1 / TA, KO, ZW, AW,AB, CH
Diaphanosoma sarsi Richard / 1.2 / HA, TA, AB, CH
Diaphanosoma lacustris Kořinek* / 1.4 / AS, HA, AW
Moina micrura Kurz / 0.9 / TA, KO, ZW, LG, AW, AB, CH
COPEPODS
Mesocyclops aequatorialis similis Van de Velde / 1.3 / HA, TA, KO, ZW, AW, CH
Megacyclops viridisviridis (Jurine)* / 2.5 / AS
Thermocyclops spp. / 0.9 / AS, HA, TA, KO, ZW, AW, CH
Thermodiaptomus galebi lacustris Defaye / 1.4 / TA
Tropodiaptomus processifer friedae Verheye & Dumont / 1.9 / KO
Tropodiaptomus kraepelini (Poppe & Mrázek) / 1.4 / AB

1

Table 3 Fish species with abbreviations and feeding habits (present study), caught in the nine study lakes indicating in how many lakes a species was observed and in which lakes. Abbreviations used: * = endemic species, ♦ = introduced exotic species, HB = herbivores, OZ = obligate zooplankton feeders, FZ = facultative zooplankton feeders, BE = benthivores, MA = macrofauna feeders, PV = piscivores. For abbreviations of Lakes see Table 1. Obligate and facultative zooplanktivores in Lake Tana according to Dejen et al. (2006)

Species / Abbr. / Family / Feeding / Lakes
Bagrus docmak / BD / Bagridae / MA / CH, AB
Barbus humilis / BH / Cyprinidae / FZ / TA
Barbus paludinosus / BP / Cyprinidae / MA / ZW, LG, AW
Barbus tanapelagius* / BT / Cyprinidae / OZ / TA
Clarias gariepinus / CF / Clariidae / FZ / HA, TA, KO, ZW, LG, AW
Cyprinus carpio♦ / CC / Cyprinidae / BE / HA. KO, ZW
Garra dembecha / GD / Cyprinidae / HB / HA, TA, KO, AW, LG, ZW
Garra ignestii / GI / Cyprinidae / FZ / AS
Garra regressus* / GR / Cyprinidae / HB / TA
Garra tana* / GT / Cyprinidae / HB / TA
Hydrocynus forskahlii / TF / Characidae / FZ / AB, CH
Labeobarbus acutirostris* / LA / Cyprinidae / MA / TA
Labeobarbus brevicephalus* / LB / Cyprinidae / FZ / TA
Labeobarbus gorgorensis* / LG / Cyprinidae / PV / TA
Labeobarbus intermedius / LI / Cyprinidae / MA, BE, PV / TA, KO, ZW, LG, AW, AB, CH
Labeobarbus longissimus* / LL / Cyprinidae / MA / TA
Labeobarbus macrophtalmus* / LMA / Cyprinidae / MA / TA
Labeobarbus megastoma* / LME / Cyprinidae / MA / TA
Labeobarbus nedgia* / LN / Cyprinidae / MA / TA
Labeobarbus truttiformis* / LT / Cyprinidae / MA, BE / TA
Lates niloticus / NP / Centropomidae / MA / AB
Oreochromis niloticus / ON / Cichlidae / FZ / AS, HA, TA, KO, ZW, LG, AW, CH
Schilbe intermedius / SI / Schilbeidae / MA / AB
Synodontis schall / SS / Mochokidae / FZ / CH, AB
Tilapia zillii♦ / TZ / Cichlidae / HB, MA / ZW
Varicorhinus beso / VB / Cyprinidae / HB / TA

References

Bottrell, H. H., A. Duncan, Z. M. Gliwicz, E. Grygierek, A. Herzig, A. Hillbricht-Ilkowska, H. Kurasawa, P. Larsson & T. Weglenska, 1976. A review of some problems in zooplankton production studies. Norwegian Journal of Zoology 24: 419-456.

Culver, D.A., M.M. Boucherle, D.J. Bean & J.W. Fletcher, 1985. Biomass of freshwater crustacean zooplankton from lengthweight regressions. Canadian Journal of Fisheries and Aquatic Sciences 42: 13801390.

5