Showing papers in "African Journal of Aquatic Science in 2005"

Marine Reserves: A Guide to Science, Design, and Use

Abstract: Island Press, Washington, USA Paperback, 336 pages ISBN 1-55963-841-9; price: US$35 African Journal of Aquatic Science 2005, 30(2): 215–216

Recommendations for the collection, preparation and enumeration of diatoms from riverine habitats for water quality monitoring in South Africa

Abstract: Diatoms have become important organisms for monitoring freshwaters and their value has been recognised for cross-border water quality monitoring in the European Union If South Africa is to include diatoms in the current suite of bioindicators, then thorough testing of diatom-based techniques is required This paper provides guidance on methods through all stages of diatom collection, preparation and examination for the purposes of water quality assessment

The predatory impact of invasive alien smallmouth bass, Micropterus dolomieu (Teleostei: Centrarchidae), on indigenous fishes in a Cape Floristic Region mountain stream

Abstract: Fish populations in the Rondegat River, a mountain stream in the Olifants-Doring system in the Cape Floristic Region, South Africa were surveyed to assess the impact of predatory alien invasive smallmouth bass Micropterus dolomieu (Lacepede) on the indigenous fishes. This was the first such attempt to quantify the predatory impacts of M. dolomieu within this region. The Rondegat River is home to five species of indigenous fish and is partially invaded by M. dolomieu, which has penetrated the lower river up to a waterfall barrier. Seasonal surveys were conducted at five sites above, and five below, the waterfall. Physical habitat was measured at each site. Four of the five indigenous fish species were absent at bass-invaded sites. Labeobarbus capensis (Smith), while still present below the waterfall, appeared to have suffered a near-total loss of post-spawning recruits. Analyses of physical habitat quality failed to explain the loss of indigenous fish below the waterfall, although sedimentation may have in...

Aquaculture: Farming Aquatic Animals and Plants

Abstract: Blackwell Publishing, Oxford, UK Paperback, 502 pages ISBN 0-85238-222-7; price: £45.00 African Journal of Aquatic Science 2005, 30(2): 213–214

Stock Enhancement and Sea Ranching: Developments, Pitfalls and Opportunities

Abstract: Second edition, Blackwell Publishing, 9600 Garsington Road, Oxford, OX4 2DQ, UK Hardback, 584 pages, 88 illustrations ISBN 1–4051–1119–4; price AU$383, £99.50 African Journal of Aquatic Science 2005, 30(1): 89–90

Oualidia lagoon, Morocco: an estuary without a river

Abstract: This study describes some physical oceanography features of an estuary maintained by fresh groundwater inflow. The mesoscale variability of currents, temperature and salinity are documented from moored current meter observations of 12 days duration at three stations. Current speeds exceeded 0.7m.s−1 during spring tides and decrease to 0.1m.s−1 during neap tides. Current directions followed the major channel axes, reversing by 180 degrees between the flood and the ebb tides. Harmonic analysis indicated that tidal currents were mainly semi-diurnal, with a predominance of the M2 harmonic, but included M4 and M6 sub-harmonics, possibly resulting from non-linear interactions of the flow with the shallow bottom and channel curvatures. Close to the lagoon entrance the water is of marine character but, further upstream, salinity decreased significantly. In the absence of river runoff, this decrease must result from some yet undisclosed underground freshwater inflow. The water renewal time estimated using the tida...

Diel and tidal variations in larval fish exchange in the mouth region of the Gamtoos Estuary, South Africa

Abstract: Diel and tidal variations in density of larval fishes were monitored over one neap and one spring tidal cycle in the mouth region of the warm temperate Gamtoos Estuary, South Africa. Data were collected over two 24h periods, using mixed method sampling with WP2 nets and a pushnet to sample both channel and margin waters. Larval fishes collected included 20 species from 12 families. Density varied with tide and diel state during the study period, with significantly higher catches recorded on the spring tide. Density of larval fishes peaked after the onset of darkness, predominantly associated with the nocturnal ebb tide. Large numbers of preflexion gobiid larvae were recorded on this tide state, this behaviour serving to facilitate movement out of the estuary for gobies that undergo a marine phase in their development. Spatial variations in larval fish distribution were also noted. Preflexion larvae were caught mainly in mid-channel waters, whilst postflexion larvae were more often encountered in the slowe...

Louisiana crayfish (Procambarus clarkii) (Crustacea: Cambaridae) in Kenyan ponds: non-target effects of a potential biological control agent for schistosomiasis

Abstract: The Louisiana crayfish (Procambarus clarkii) has been proposed as a biological control agent for the intermediate snail hosts (Bulinus and Biomphalaria spp.) of human schistosomes (Schistosoma haematobium and S. mansoni) in Kenya. Using laboratory and field experiments, we examined the potential non-target effects such introductions might have on native Kenyan aquatic biota. In an eight-week laboratory mesocosm experiment, crayfish decreased water clarity and reduced populations of slow-moving, benthic invertebrates including non-target snails, chironomid larvae and oligochaetes. Similar declines in invertebrates occurred in an unreplicated 35-day whole-pond experiment. In addition, water lilies disappeared from the pond into which crayfish were introduced, while water lilies remained abundant in the pond without crayfish. Given the large impacts of crayfish on native invertebrate and macrophyte communities in our experiments, promotion of this crayfish as a biological control agent should not proceed wit...

The impact of dredging on macrobenthic invertebrates in a tributary of the Warri River, Niger delta

Abstract: The macrobenthic invertebrates of a canal, created from a tributary of the Warri River in the mangrove swamp of the Niger Delta, Nigeria, were studied before and after dredging. In the canal dredging resulted in at least a 93% decrease in the benthic population while the Margalef's diversity index reduced from 3.8 to 1.4. Of the 15 species identified during the pre-dredging studies, only Nereis operta and Baetis sp. were recovered after dredging. The site 500m downstream of the canal was also slightly impacted, showing a 31% decrease in population. We conclude that the drastic reduction of benthic species is due to the direct destruction of benthic species, larvae and habitat, as well as settling turbidity plumes, reduction of sediment nutrients, physical disturbance and, physiological and toxic stress. To conserve biodiversity it is recommended that mitigation measures should be put in place by stakeholders involved in dredging and that long-term monitoring of dredged canals is carried out to ensure that...

The effect of some environmental factors on zooplankton community biodiversity in Lake Qarun, Egypt

Abstract: The zooplankton of Lake Qarun was studied January–December 2003. A total of 26 species was recorded, amongst which protozoa, primarily ciliophora, were most abundant (79% of the species total), followed by rotifera (13%) and copepoda (8%). The average density ranged from 965–1 452 l–1. The highest density (2 884 l–1) was recorded during April and the lowest density (231/l) in May. Protozoa were represented by 16 taxa. Euplotes, Tintinnopsis and Helicostomella were the most abundant genera (47%, 34% and 16% of the total protozoa, respectively), amongst which eight taxa were recorded for the first time. Rotifera were represented by seven species, with Brachionus and Synchaeta being the most abundant genera (89% and 11% of the total rotifers, respectively). Copepoda were represented by Paracartia latisetosa, which comprised 93% of the total number of adult copepods, Apocyclops banamensis and Mesochra heldti. Lake Qarun is highly eutrophic and is suitable for the ranching of marine fishes, particularly plankton-feeding species which can consume the high quantities of plankton present which otherwise would not be utilised. Keywords: biodiversity, environmental parameters, Lake Qarun, zooplanktonAfrican Journal of Aquatic Science 2005, 30(2): 195–200

Africa's Clarias gariepinus (Teleostei: Clariidae) appears in rivers in Brazil

Abstract: (2005). Africa's Clarias gariepinus (Teleostei: Clariidae) appears in rivers in Brazil. African Journal of Aquatic Science: Vol. 30, No. 2, pp. 201-202.

Langebaan – A new type of estuary?

Abstract: A detailed study of the Langebaan system by Day (1959) indicated that Langebaan Lagoon (Figure 1) was a sheltered inlet of the sea and not an estuary. Consequently, this system was not included in an analysis of South African estuarine types (Whitfield 1992) and it was also omitted from the bibliographic database on South African estuaries (Whitfield 2000). However, estuarine research — as with all scientific disciplines — is continually evolving and placing new perspectives on previously-accepted paradigms. In the light of recent aquifer research in and around Langebaan it is perhaps appropriate to review the earlier conclusion about the classification of this system. Hilmi et al. (2005) described the physical oceanographic features of the Oualidia Lagoon in Morocco and suggested that groundwater inflow of approximately 0.25m s was a valid reason for classifying this system as an estuary. The waters close to the mouth are of ‘marine character’, whereas further upstream the salinity decreases ‘significantly’. In the absence of river run-off, these authors concluded that this salinity decrease must result from an underground freshwater supply that has yet to be located. The original definition of an estuary by Pritchard (1967) was as follows: ‘An estuary is a semi-enclosed body of water which has a free connection with the open sea and within which sea water is measurably diluted with fresh water derived from land drainage’. This definition was later modified by Day (1980) to cater for those estuaries that are sometimes closed by sand bars forming across the mouth, i.e. ‘An estuary is a partially enclosed coastal body of water which is either permanently or periodically open to the sea and within which there is a measurable variation of salinity due to the mixture of sea water with fresh water derived from land drainage’. Both the above definitions refer to ‘...fresh water derived from land drainage’ in order to differentiate between the dilution of sea water caused by direct precipitation, and dilution originating from land drainage. Neither definition mentions or distinguishes between fresh water received via a river or groundwater inputs, both of which are technically derived from land drainage. Indeed, it is highly probable that most, if not all, water bodies currently recognized as estuaries receive fresh water from both sources. However, apart from systems such as Lake St Lucia, where groundwater seepage is vital to the creation of reduced salinity refuge areas during extreme hypersaline conditions (Hutchison and Midgley 1978), South African researchers have tended to focus only on the impact of riverine inflows into estuaries (Whitfield and Wooldridge 1994). Day (1959) outlined the ecology of Langebaan Lagoon and stressed that it is not an estuary but a sheltered arm of the sea. The proceedings of a major research symposium in 1976 on Saldanha Bay and Langebaan Lagoon were subsequently published as a series of formal papers (inter alia Grindley 1977, Henry and Mostert 1977, Puttick 1977, Shannon and Stander 1977) but no mention was made of the possibility that Langebaan was a unique type of estuary. However, in 1981 an entire chapter in the book Estuarine Ecology with Particular Reference to Southern Africa (Christie 1981) was devoted to primary production in Langebaan Lagoon, and this system was also included in a review chapter on knowledge of estuaries in the region (Day 1981). The reason given for the inclusion of Langebaan Lagoon in the above book was the extensive list of typically estuarine species occurring in this system. More recently, the Langebaan system received considerable coverage by a number of contributors in the book Estuaries of South Africa (Allanson and Baird 1999). Typical Short Note

The influence of downstream changes in water quality on phytoplankton composition in the Vaal River, South Africa

Abstract: Links between spatial differences in phytoplankton composition and changes in environmental variables in the Vaal River, South Africa, were investigated. Multivariate analysis showed that the most important environmental variables influencing algal abundance were turbidity, conductivity, nutrient concentrations and temperature. Of these variables conductivity, phosphorus, nitrogen and SiO2-Si showed spatial differences in concentration. The average nutrient concentrations (phosphorus, nitrogen and SiO2-Si) showed downstream decreases, while the average conductivity increased in a downstream direction. Spatial changes in phytoplankton composition could also be illustrated and were especially apparent when the contribution of Cyanobacteria (blue-green bacteria or blue-green algae), Bacillariophyceae and Euglenophyceae to the total algal composition was taken into account.

Fish communities along environmental gradients within the Comoé River basin, Côte d'Ivoire

Abstract: Eighty-four sites in the Comoe basin (Cote d'Ivoire, West Africa) were sampled to identify fish assemblages and their relationships with some environmental variables. Seventy-six freshwater fish species were collected from 22 families and 44 genera: 11 marine and/or brackish water species, one introduced species, and one hybrid form. Nine species were reported for the first time in this basin. Seventeen species collected previously were not detected. Among the fishes sampled, characids were the most abundant. Statistical analysis identified four groups of sites characterised by distinct fish assemblages within the Comoe basin. Assemblages from Comoe National Park were characterised by a higher proportion of Mormyridae. In the upper catchment, Cyprinidae were predominant. Downstream, assemblages were distinguished by the presence of marine and/or brackish-water fish species and the absence of Mochokidae. The middle catchment was characterised by the presence of more Characidae, Clariidae and Cichlidae than...

Namibia's Marine Environment

Abstract: (2005). Namibia's Marine Environment. African Journal of Aquatic Science: Vol. 30, No. 2, pp. 217-217.

Interactions between fish and snails in a Zimbabwe pond, with particular reference to Sargochromis codringtonii (Pisces: Cichlidae)

Abstract: The impact of fishes on snail densities in a 100 x 12m pond was assessed from October 2000 to May 2002, using a fish exclosure experiment. Snail species included numerically dominant Bulinus globosus (ca 85%) as well as B. tropicus , Biomphalaria pfeifferi , Lymnaea natalensis and Melanoides tuberculata . Six fish species were present in the ponds prior to the start of the experiment; these were Tilapia rendalli , Oreochromis mossambicus , O . macrochir , Clarias gariepinus , Kneria auriculata and an unidentified Labeo species. At the beginning of the experiment 85 Sargochromis codringtonii were introduced into the pond. All fish species were periodically monitored by seine netting and the stomach contents of a sample of these was analysed. For the first five months of the experiment Bulinus globosus numbers were low, both inside the fish exclosures and in the adjacent control areas but, from April 2001 onwards, snail numbers inside the exclosures were consistently higher than those in the control areas. At the end of the experiment the density of B. globosus was 150.5snails m –2 in the exclosures and 4.7snails m –2 in the control areas. The other snail species showed the same trend, but the differences were less pronounced. Sargochromis codringtonii was the only fish species that was found to feed on snails and since this species became successfully established in the pond it was assumed to be responsible for the snail mortality outside the exclosures. Whilst this experimental design did not separate the effects of S . codringtonii from those of the other fish species, it does provide strong evidence that fish are important in the control of B . globosus , an intermediate host for schistosomiasis. African Journal of Aquatic Science 2005, 30(1): 45–48

Zooplankton community changes in Nhlabane estuary, South Africa, induced by man-made structures and drought

Abstract: The Nhlabane estuary and coastal lake system has suffered a number of man-made impacts since 1977, when the lake and estuary were separated by the construction of a barrage. More recent man-made events included the construction of temporary sand walls, mid-way along the estuary, to allow crossing of a mining dredger during 1993. These walls remained in place until 1996, coinciding with a local drought period between 1991 and late 1995, during which time the estuary mouth remained closed. The present study investigates changes in the zooplankton community of Nhlabane estuary between February 1992 and October 1996. Due to continuous freshwater inputs from groundwater seepage, the then closed estuary soon became fresh. This led to significant changes in the zooplankton community, including the appearance of freshwater taxa such as rotifers, cyclopoids ( Mesocyclops sp. and Thermocyclops sp. ), freshwater cladocerans and insect larvae, reflecting the freshwater conditions. Most estuarine species became less abundant or were absent two years after mouth closure. The estuarine copepod Pseudodiaptomus hessei was least affected and remained dominant. The copepod Acartia natalensis was absent after the first two sampling sessions and only reappeared after the mouth was breached in August 1995. Other taxa that were adversely affected included the mysid Mesopodopsis africana , and larval stages of polychaetes, decapods and fish. Some meroplankton taxa recovered after the mouth reopened. African Journal of Aquatic Science 2005, 30(1): 29–35

The use of multivariate analysis as a tool to illustrate the influence of environmental variables on phytoplankton composition in the Vaal River, South Africa

Abstract: The highly eutrophic Vaal River system is subjected to algal blooms that cause problems ranging from aesthetically unacceptable conditions to the release of toxins. In order to understand how environmental variables influence one another and to determine the key environmental variables that affect phytoplankton composition, multivariate analyses were applied. Results showed that the most important environmental variables influencing one another, as well as phytoplankton composition, were turbidity, temperature, conductivity and nutrients, such as SiO2-Si. Turbidity influenced phytoplankton biomass through its effect on light availability in the water column. In general, Cyanobacteria, Euglenophyceae and the filamentous centric diatom Aulacoseira granulata were favoured by high temperatures, low inorganic N:P ratios and low conductivity levels, while the unicellular centric diatoms were favoured by the opposite conditions. Green algae were capable of tolerating wider environmental variability than other al...

Growth, reproduction and population structure of Diplotaxodon limnothrissa in the southeast arm of Lake Malawi

Abstract: Diplotaxodon limnothrissa is a widely distributed species occurring throughout Lake Malawi from the surface to a depth of at least 220m. It is probably the most abundant cichlid in the lake, with biomass estimates of around 87 000t in the pelagic zone alone. The species is exploited commercially in the southern part of the lake but, since its inception, this fishery has never been assessed. Analysis of sectioned sagittal otoliths revealed that D. limnothrissa is a slow-growing and relatively long-lived species, attaining ages in excess of 10 years. Length-at-age was described using the von Bertalanffy growth model, with combined-sex growth described as Lt = 211.21(1 − exp(−0.24(t + 1.36)))mm TL. Females matured at 139mm TL at an estimated age of 3.18 years. Total, natural and fishing mortalities were estimated at 0.63yr−1, 0.38yr−1 and 0.25yr−1 respectively.

Modelling highly variable daily maximum water temperatures in a perennial South African river system

Abstract: Thirty-three months of observed hourly water temperatures were used to calculate daily maximum water temperatures for nine sites within the Sabie-Sand River system, Mpumalanga Province, South Africa. A suite of statistical models for simulating daily maximum water temperatures, of differing complexity and using inputs of air temperature, flow rates, rainfall and relative humidity, were developed and verified. Whilst all models performed well, the most suitable was a site-specific multiple linear regression model using inputs of mean daily air temperature, minimum daily air temperature and relative humidity. The inclusion of a flow rate term would greatly enhance the utility value of such models, but insufficient flow rate data is often a limiting factor. For pragmatic purposes, a simple non-linear regression model using mean daily air temperatures is probably adequate for many areas of South Africa. A generic statistical water temperature model at a daily time step is difficult to achieve, whereas catchme...

Fecundity and sexual maturity of the crab Macrophthalmus depressus (Brachyura: Ocypodidae) from Inhaca Island, Mozambique

Abstract: Some reproductive aspects of the ocypodid crab Macrophthalmus depressus, were investigated, with emphasis on fecundity and sexual maturity. Random intertidal crab samples taken in October 2002 were identified, sexed, measured, checked for the presence of eggs on female pleopods, dissected for gonad analysis and their egg numbers were determined. Fecundity averaged 1249.86 ± 991.96 eggs, ranging from 100 to 5000 eggs, increasing in accordance with female size. A very low variation in number of eggs was observed within the same size class, probably indicating synchronous spawning within the same reproductive season. Gonad analysis suggested that females and males become mature at carapace widths of 13.4 and 13.6mm, respectively. The potential effects of variations in fecundity in this species, and in the Ocypodidae family, were compared and discussed.

Comparing macrophyte herbivory by introduced Louisiana crayfish ( Procambarus clarkii ) (Crustacea: Cambaridae) and native Dytiscid beetles ( Cybister tripunctatus ) (Coleoptera: Dytiscidae), in Kenya

Abstract: The omnivorous Louisiana crayfish, Procambarus clarkii, has caused significant changes to macrophyte communities worldwide and may have similar negative effects in Kenya if used as a biological control agent for snails harbouring human schistosomes. Here we examine how herbivory by the introduced Louisiana crayfish might change macrophyte abundance and species composition relative to herbivory by a prevalent native beetle Cybister tripunctatus. Our observations are thought to be the first on the consumption of live macrophytes by adult dytiscid beetles, which are commonly known as predaceous diving beetles. In a laboratory experiment, we compare herbivory rates and macrophyte species-selectivity between the beetle and the crayfish. Combining the herbivory rates with population estimates of crayfish and beetles in a local pond, we estimate that herbivory in the natural environment is of the same order of magnitude. Preferences among macrophyte species are also similar between herbivores, except that crayfi...

Fish migrations in two seasonal streams in Zimbabwe

Abstract: Fish migrations into the streams of seasonally-flooded depressions (or dambos) that cover the central plateaus of Africa are a well-known phenomenon to scientists and lay people alike. However, the factors causing seasonal migrations are poorly understood and most scientific references to them are anecdotal, lacking rigorous description. Fish migrations in two dambos in Zimbabwe were investigated during the 1999/2000 rainy season, by electrofishing and using traps. The fish fell into two categories: those that used the dambo, and those that remained in the main river. At the beginning of the rainy season Barbus paludinosus, B. lineomaculatus, Clarias gariepinus and Tilapia sparrmanii moved from the perennial river into the small dambo streams and spawned there, then moved back to the perennial river, leaving their young in the dambo, which acted as a nursery area. Barbus spp. were the most numerous migrants and they moved mainly during daylight hours. Other fish species present in the system included Opsa...

Artisanal gill-net fishery catches of the catfish, Schilbe intermedius (Teleostei: Schilbeidae), in two tributaries of the Ouémé River, Bénin, West Africa

Abstract: Artisanal fishery gill-net catches of the catfish Schilbe intermedius were studied in the Okpara and Zou tributaries of the Oueme River, Benin in 1999 and 2000. The largest fish caught at the Toue and Kpassa stations measured 26.2cm and 24.5cm (TL) respectively. The success of artisanal fishing for schilbeids varied during the day, with the highest fish catches being recorded at approximately 22h00 and at 07h00 and the lowest between 13h15 and 16h15. The monthly production at Kpassa varied between 9.0g and 900.0g (average 206.3g) and between 3.3g and 17 320g (average 2 603.4g) at Toue. The monthly production fluctuated considerably. At the two stations, fewer fish were caught each month in the second year than in the same months in the first year. Nets of between 10 and 15mm stretch mesh were the most efficient. Above 15mm, gill-net fishing became less effective. Large fish were often taken with gill-nets of 20–30mm stretch mesh. Beyond these mesh sizes, the gill-net yield and catch decreased.

Management advice for the Diplotaxodon limnothrissa (Teleostei: Cichlidae) resource in the south-east arm of Lake Malawi, based on per-recruit analysis

Abstract: Diplotaxodon limnothrissa is a widely distributed species occurring throughout Lake Malawi and is probably the most abundant cichlid in the pelagic zone of the lake. The species is exploited commercially in the south-east arm of the lake, but since the fishery's inception the resource has never been assessed. Per-recruit analysis indicated that the resource is under-exploited, with current spawner biomass per-recruit between 55% and 74% of pristine levels.

Assessing the true status of the fish species Labeo cylindricus (Peters 1868) (Teleostei: Cyprinidae) in Lake Baringo, Kenya

Abstract: No Abstract Keywords: endangered species, gill-net, Labeo cylindricus, Lake Baringo African Journal of Aquatic Science 2005, 30(2): 203–205

Reproductive biology of a riverine cyprinid, Labeo umbratus (Teleostei: Cyprinidae), in small South African reservoirs

Abstract: The reproductive and recruitment characteristics of moggel, Labeo umbratus, populations were examined in four small South African reservoirs. Reproduction, characterised by an extended spawning season, high fecundity, short incubation time and rapid larval development, appears to be ideally suited to the highly variable environment of small reservoirs. Evidence suggested that L. umbratus spawns in the reservoirs. In two reservoirs where samples were conducted monthly, GSI (gonado-somatic index) was positively correlated with both water temperature and day length, whilst the CPUE (catch per unit effort) of juveniles was not related to any environmental variable. The success of moggel spawning appeared to increase when there was early spring and consistent summer rainfall.

Remarkable Shrimps: Adaptations and Natural History of the Carideans

Abstract: University of Oklahoma Press, Norman, Oklahoma Hardback, 316 pages ISBN 0-8061-3555-7; price: US$59.95MT African Journal of Aquatic Science 2005, 30(2): 211–212

Susceptibility of schistosome host snails to predation by sciomyzid flies (Diptera: Sciomyzidae) in South Africa

Abstract: Afrotropical sciomyzids are predators of freshwater pulmonate snails. Studies have indicated that these flies may play a role in controlling medically important (target) snail populations, especially snail intermediate hosts of schistosomes. This study investigated the preferential feeding of Sepedon scapularis and S. neavei on four commonly-occurring molluscs in South Africa. The feeding behaviour of these flies was observed on a polyphagous diet consisting of Bulinus tropicus, Bu. forskalii, Bu. africanus and Biomphalaria pfeifferi. Laboratory experiments were set up with a constant number of 12 live snails per petri dish. Snail mortality was recorded daily for the duration of the larval period. Preliminary results show that both fly species fed preferentially upon Bu. africanus and Bi. pfeifferi. Overall, S. neavei killed more target snails than S. scapularis did. The preference of both fly species was Bi. pfeifferi, followed by Bu. africanus, Bu. tropicus and Bu. forskalii. These sciomyzid species are...