DOCSLIB.ORG

The Potential for Mozambique Tilapia Oreochromis Mossambicus to Invade the Murray–Darling Basin and the Likely Impacts: a Review of Existing Information

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
The Potential for Mozambique Tilapia Oreochromis Mossambicus to Invade the Murray–Darling Basin and the Likely Impacts: a Review of Existing Information Mozambique tilapia The potential for Mozambique tilapia Oreochromis mossambicus to invade the Murray–Darling Basin and the likely impacts: a review of existing information Illustration: Marjorie Crosby-Fairall Michael Hutchison, Zafer Sarac and Andrew Norris Department of Employment, Economic Development and Innovation www.mdba.gov.au Murray–Darling Basin Authority The MDBA’s preference is that you attribute this publication (and any material sourced from it) using the following wording: Title: Mozambique tilapia: The potential for Mozambique Published by the Murray–Darling Basin Authority. tilapia Oreochromis mossambicus to invade the MDBA publication number: 153/11 Murray–Darling Basin and the likely impacts: a review of ISBN: 978-921914-19-5 (on-line) existing information ISBN: 978-921914-20-1 (print) Source: Licensed from the Murray–Darling Basin Authority under a Creative Commons Attribution 3.0 Australia Licence © Murray–Darling Basin Authority for and on behalf of the Commonwealth of Australia, 2011. Authors: Michael Hutchison, Zafer Sarac and Andrew Norris – Department of Employment, Economic With the exception of the Commonwealth Coat of Arms, Development and Innovation the MDBA logo, all photos, graphics and trade marks, this publication is provided under a Creative Commons The Murray–Darling Basin Authority does not necessarily Attribution 3.0 Australia Licence. endorse the content of this publication. The MDBA provides this information in good faith but to the extent permitted by law, the MDBA and the Commonwealth exclude all liability for adverse consequences arising directly or indirectly from using any information or material http://creativecommons.org/licenses/by/3.0/au contained within this publication. Contents Contents Executive summary............ 5 Introduction............ 8 Tolerance of Mozambique tilapia to high and low temperatures and other physico-chemical parameters ............ 10 Reproduction ............ 23 Other important biological attributes of tilapia............ 28 Climate change and its potential influence on tilapia in the Murray–Darling Basin............ 31 Reported and potential impacts of tilapia............ 33 Conclusions............ 50 Acknowledgements............ 50 References............ 51 3 Murray–Darling Basin Authority Recommendations From an ecological perspective, it is recommended that programs that promote early detection of tilapia and prevention of infestation in the Murray–Darling Basin be made a high priority. The best way of protecting aquatic ecosystems and native fish populations from the possible impacts is to make sure tilapia do not enter the Murray–Darling Basin system. A key facet of any prevention program for tilapia must be education and awareness, as people are a primary factor in the spread of this species in Australia. In order to estimate the potential range of Executive summary tilapia in the Murray–Darling Basin, this report Mozambique tilapia (Oreochromis mossambicus) attempts to: is a major pest fish species in Australia. • predict the range in the Basin where A successful invader, it has managed to tilapia may survive through colder dominate natural waterways into which it has winter temperatures been introduced. It is not currently found in • determine the length of the feasible breeding the Murray–Darling Basin; however, it has season (including the number of broods established thriving populations in catchments possible in that time) in different ranges neighbouring the Basin. In some places, it is only • determine the portion of the year in which a short distance from the northern headwaters. tilapia may feed and is therefore likely to have There is a high risk that this species will be impacts on ecological processes through the introduced to the Basin. food web. Despite the high risk of introduction, little work This includes: has been done to estimate the potential range • estimating the lower temperature tolerance tilapia might occupy in the Basin, or to predict its for tilapia based on literature and survival possible impacts on natural, economic or social rates of populations already infesting assets. This report provides a literature review locations in Queensland and impact assessment in an attempt to provide some information about these potential threats. • identifying the minimum winter temperatures recorded at different locations throughout ESTIMATING THE POTENTIAL the Basin RANGE OF MOZAMBIQUE TILAPIA • using the distribution of native fish with similar temperature tolerances to tilapia as IN THE MURRAY–DARLING BASIN a surrogate. An important factor in determining the extent of The literature shows varying lower temperature impacts of Mozambique tilapia is to estimate the tolerances of tilapia, including evidence that potential range it could occupy in the Murray– saline waters can enhance this species’s cold Darling Basin. Tilapia has a wide and varied diet tolerance. After investigating lower thermal and can occupy a diverse range of habitats, from tolerances, this report took the view that: freshwater to hypersaline conditions; therefore, • conservatively, a location with a water its distribution is unlikely to be limited by many temperature minimum of 10°C can be viewed environmental, physical or chemical conditions. as a place where tilapia is highly likely to However, the one factor that appears to affect survive the winter tilapia is its vulnerability to cold temperatures. Tilapia is traditionally viewed as a tropical to • between 8.0 and 9.9°C, there is still a warm-temperate species; therefore, its survival reasonable probability that tilapia would and potential distribution in the Basin is likely survive the winter to be governed by its ability to survive lower • below 7.9°C, the survival of tilapia in the water temperatures and to live through winter Basin would be compromised. periods (overwinter). Similarly, the likelihood of Based upon these suppositions and the minimum tilapia populations reaching numbers significant water temperature data available, Mozambique enough to cause impacts in waterways also tilapia have the potential to infest the northern relates to temperature suitability. In essence, Basin in Queensland and parts of New South water temperatures in the Basin must remain Wales, through the western inland catchments warm enough to permit feeding and to allow of NSW and down to the Lower Lakes and lower sufficient time for breeding. Murray in South Australia. This equates to a core distribution occupying approximately 50% of the Basin. 5 Murray–Darling Basin Authority Most of the Darling River is therefore capable were to be introduced. Experiences in both of supporting overwintering populations of north Queensland and Western Australia have tilapia. Water temperatures of rivers flowing demonstrated rapid dispersal of tilapia. The rate from Victoria into the River Murray and most of spread has been exacerbated where human- of the rivers in southern New South Wales are assisted dispersal is combined with the natural likely to be too cold to support overwintering abilities of tilapia to move up and downstream tilapia. However, it is possible that there will be of an introduction site. Dispersal rates of up some pockets of warmer water, or some years in to 250 km per year have been recorded in which sites may permit overwintering of tilapia such cases. in parts of southern and central New South Tilapia are highly adaptable and have been Wales. These warm water refuges may also reported to aestivate (maintain a prolonged state allow tilapia to have temporary expansions and of inactivity) in wet river sands in their native extend the range in which impacts are felt from African habitat. This enables them to survive invasion of this species in the Basin. However, as river pools dry. This would enable tilapia to it is important to note that an increase in winter rapidly recolonise areas when dry periods end. minima of only around 2°C could enable tilapia Under adverse conditions such as drought, to overwinter in most of the lowland areas of tilapia can switch from a normal growth and the Basin. This would be entirely feasible under maturation rate (where fish first breed at two moderate climate change scenarios. In addition, or three years old and at a size of 25–35 cm), to this report used the best estimates of water stunted populations where fish mature at very temperature it could find. Therefore, it would be small sizes (9–10 cm) and breed at only a few possible to extend or contract these distribution months old. As noted above, tilapia can produce range estimates with more comprehensive 4–6 broods over a summer season. Tilapia also temperature records. provide parental care, where the female broods Tilapia is capable of sustaining viable populations eggs and young in her mouth to protect them under the conditions found in much of the from predation. These traits and behaviours Murray–Darling Basin, as breeding and feeding mean tilapia have the capacity to rapidly increase can occur for significant portions of the year. their numbers and dominate waterways. In the northern parts of the Basin, and many southern parts, median water temperatures THE POTENTIAL IMPACTS could see a breeding season of at least OF TILAPIA IN THE 3–6 months in duration with around 4–6 broods for each female in each breeding season. Tilapia MURRAY–DARLING BASIN would remain prolific breeders under such Tilapia impacts have been recorded in a conditions. It could be expected that tilapia may number of locations both in Australia and
Load more

Recommended publications
  • MANAGEMENT and VALUE CHAIN of NILE TILAPIA CULTURED in PONDS of SMALL-SCALE FARMERS in MOROGORO REGION, TANZANIA Sebastian W. Ch
    MANAGEMENT AND VALUE CHAIN OF NILE TILAPIA CULTURED IN PONDS OF SMALL-SCALE FARMERS IN MOROGORO REGION, TANZANIA Sebastian W. Chenyambuga , Nazael A. Madalla and Berno V. Mnembuka Department of Animal Science, Sokoine University of Agriculture, P.O. Box 3004, Morogoro, Tanzania. Abstract A study was carried out to assess production performance and value chain of Nile tilapia grown in ponds of small-scale farmers in Morogoro region, Tanzania. Information was collected through individual interviews of 30 fish farmers. The main reasons for culturing fish were provision of animal protein food for home consumption (66.7%) and generation of income (23.3%). Fish farming contributed 10.6% of household annual income and was ranked second to crop production (50%). The majority of the farmers were fertilizing their ponds with chicken manure (30.0%) and cattle manure (23.3%). Most farmers (73.3%) cultured pure stand of Nile tilapia and only few (26.7%) practiced polyculture of Nile tilapia and African catfish. All farmers depended on natural food as a source of feed for their fish. Moreover, the farmers were feeding maize bran (96.7%), vegetables (66.7%), and kitchen leftovers (13.3%) as supplementary feeds. Men were responsible for purchasing and stocking fingerlings (60.0%), feeding (40.0%), pond maintenance (53.3%), harvesting (60.0%) and selling (43.3%). Women were mainly involved in fish processing (76.7%). The average period from stocking to harvesting was 5.75 ± 0.18 months for Nile tilapia and the mean yield was 6,946.2 kg/ha per year. About 22.2% of the harvested fish were consumed at home and the remaining (77.8%) were sold.
    [Show full text]
  • Disease List for Aquaculture Health Certificate
    Quarantine Standard for Designated Species of Imported/Exported Aquatic Animals [Attached Table] 4. Listed Diseases & Quarantine Standard for Designated Species Listed disease designated species standard Common name Disease Pathogen 1. Epizootic haematopoietic Epizootic Perca fluviatilis Redfin perch necrosis(EHN) haematopoietic Oncorhynchus mykiss Rainbow trout necrosis virus(EHNV) Macquaria australasica Macquarie perch Bidyanus bidyanus Silver perch Gambusia affinis Mosquito fish Galaxias olidus Mountain galaxias Negative Maccullochella peelii Murray cod Salmo salar Atlantic salmon Ameirus melas Black bullhead Esox lucius Pike 2. Spring viraemia of Spring viraemia of Cyprinus carpio Common carp carp, (SVC) carp virus(SVCV) Grass carp, Ctenopharyngodon idella white amur Hypophthalmichthys molitrix Silver carp Hypophthalmichthys nobilis Bighead carp Carassius carassius Crucian carp Carassius auratus Goldfish Tinca tinca Tench Sheatfish, Silurus glanis European catfish, wels Negative Leuciscus idus Orfe Rutilus rutilus Roach Danio rerio Zebrafish Esox lucius Northern pike Poecilia reticulata Guppy Lepomis gibbosus Pumpkinseed Oncorhynchus mykiss Rainbow trout Abramis brama Freshwater bream Notemigonus cysoleucas Golden shiner 3.Viral haemorrhagic Viral haemorrhagic Oncorhynchus spp. Pacific salmon septicaemia(VHS) septicaemia Oncorhynchus mykiss Rainbow trout virus(VHSV) Gadus macrocephalus Pacific cod Aulorhynchus flavidus Tubesnout Cymatogaster aggregata Shiner perch Ammodytes hexapterus Pacific sandlance Merluccius productus Pacific
    [Show full text]
  • Oreochromis Rukwaensis) Ecological Risk Screening Summary
    Lake Rukwa Tilapia (Oreochromis rukwaensis) Ecological Risk Screening Summary U.S. Fish & Wildlife Service, March 2012 Revised, July 2018 Web Version, 6/4/2020 Organism Type: Fish Overall Risk Assessment Category: Uncertain 1 Native Range and Status in the United States Native Range From Froese and Pauly (2018): “Africa: Lake Rukwa in Tanzania.” From Shechonge et al. (2019): “Oreochromis rukwaensis (Hilgendorf & Pappenheim 1903) previously known only from Lake Rukwa was present in an upstream section of the Ruaha river system, where a major exploited population was recorded at the Mtera Dam Lake [Tanzania].” Status in the United States No records of Oreochromis rukwaensis occurrences in the United States were found. No information on trade of O. rukwaensis in the United States was found. 1 The Florida Fish and Wildlife Conservation Commission has listed the tilapia, Oreochromis rukwaensis as a prohibited species. Prohibited nonnative species (FFWCC 2020), "are considered to be dangerous to the ecology and/or the health and welfare of the people of Florida. These species are not allowed to be personally possessed or used for commercial activities." Means of Introductions in the United States No records of Oreochromis rukwaensis occurrences in the United States were found. Remarks No additional remarks. 2 Biology and Ecology Taxonomic Hierarchy and Taxonomic Standing According to Eschmeyer et al. (2018), Oreochromis rukwaensis (Hilgendorf and Pappenheim 1903) is the current valid name of this species. From ITIS (2018): Kingdom Animalia
    [Show full text]
  • Reintroduction Plan for the Purple- Spotted Gudgeon in the Southern Murray–Darling Basin
    Reintroduction plan for the Purple- spotted Gudgeon in the southern Murray–Darling Basin Photo: Arthur Mostead Authors - Michael Hammer, Thomas Barnes, Leanne Piller & Dylan Sortino Aquasave Consultants, Adelaide Published by Murray–Darling Basin Authority. MDBA Publication No 45/12 ISBN 978-1-922068-54-5 (online) © Murray–Darling Basin Authority for and on behalf of the Commonwealth of Australia, 2012. With the exception of the Commonwealth Coat of Arms, the MDBA logo, all photographs, graphics and trademarks, this publication is provided under a Creative Commons Attribution 3.0 Australia Licence. http://creativecommons.org/licenses/by/3.0/au The MDBA’s preference is that you attribute this publication (and any material sourced from it) using the following wording: Title: Reintroduction Plan for the Southern Purple-spotted Gudgeon in the southern Murray— Darling Basin Source: Licensed from the Murray–Darling Basin Authority, under a Creative Commons Attribution 3.0 Australia Licence. Authors: Michael Hammer, Thomas Barnes, Leanne Pillar and Dylan Sortino. Editor: Jane Tuckwell The MDBA provides this information in good faith but to the extent permitted by law, the MDBA and the Commonwealth exclude all liability for adverse consequences arising directly or indirectly from using any information or material contained within this publication. Cover Image: Lower Murray Southern Purple-spotted Gudgeon in captivity–adults, eggs and juveniles. Photos by Michael Hammer i Reintroduction plan for the Southern Purple-spotted Gudgeon in the southern Murray—Darling Basin. Summary The Southern Purple-spotted Gudgeon is a small, colourful freshwater fish with a distinct genetic conservation unit in the southern Murray–Darling Basin (MDB).
    [Show full text]
  • Lake Chala Tilapia (Oreochromis Hunteri) Ecological Risk Screening Summary
    Lake Chala Tilapia (Oreochromis hunteri) Ecological Risk Screening Summary U.S. Fish & Wildlife Service, March 2012 Revised, June 2018 Web Version, 12/15/2020 Organism Type: Fish Overall Risk Assessment Category: Uncertain Photo: D. H. Eccles. Licensed under Creative Commons BY-NC 3.0. Available: http://www.fishbase.org/photos/PicturesSummary.php?StartRow=0&ID=2032&what=species&T otRec=2. (June 18, 2018). 1 Native Range and Status in the United States Native Range From Froese and Pauly (2018a): “Africa: endemic to Lake Chala [Seegers et al. 2003].” 1 Status in the United States No records of Oreochromis hunteri in trade or in the wild in the United States were found. The Florida Fish and Wildlife Conservation Commission has listed the tilapia Oreochromis hunteri as a prohibited species. Prohibited nonnative species (FFWCC 2018), "are considered to be dangerous to the ecology and/or the health and welfare of the people of Florida. These species are not allowed to be personally possessed or used for commercial activities. All species in the genus Oreochromis are considered regulated Type A species in Washington. Regulated Type A species (Washington State Senate 2019) are “nonnative aquatic animal species that pose a low to moderate invasive risk that can be managed based on intended use or geographic scope of introduction, have a beneficial use, and are a priority for department-led or department-approved management of the species' beneficial use and invasive risks.” Possession of any species of tilapia is prohibited without permit in the State of Louisiana (Louisiana State Legislature 2019). O. amphimelas falls within Group I of New Mexico’s Department of Game and Fish Director’s Species Importation List (New Mexico Department of Game and Fish 2010).
    [Show full text]
  • Heavy Metals Bio-Accumulation in Tilapia and Catfish Species in Lake Rukwa Ecosystem Tanzania
    The University of Dodoma University of Dodoma Institutional Repository http://repository.udom.ac.tz Natural Sciences Journal Articles 2020 Heavy metals bio-accumulation in tilapia and catfish species in Lake Rukwa ecosystem Tanzania Mapenzi,Levinus Leonard;Shimba, Moses Joel;Moto, Edward Angelo;Maghembe, Reuben Silas;Mmochi, Aviti John Elsevier Mapenzi, L. L., Shimba, M. J., Moto, E. A., Maghembe, R. S., & Mmochi, A. J. (2020). Heavy metals bio-accumulation in tilapia and catfish species in Lake Rukwa ecosystem Tanzania. Journal of Geochemical Exploration, 208, 106413. http://hdl.handle.net/20.500.12661/2465 Downloaded from UDOM Institutional Repository at The University of Dodoma, an open access institutional repository. Journal of Geochemical Exploration 208 (2020) 106413 Contents lists available at ScienceDirect Journal of Geochemical Exploration journal homepage: www.elsevier.com/locate/gexplo Heavy metals bio-accumulation in tilapia and catfish species in Lake Rukwa ecosystem Tanzania T ⁎ Levinus Leonard Mapenzia,b, , Moses Joel Shimbaa, Edward Angelo Motoa, Reuben Silas Maghembec, Aviti John Mmochib a Department of Biology, College of Natural and Mathematical Sciences, P.O. Box 338, University of Dodoma, Tanzania b Institute of Marine Sciences, University of Dar es Salaam, P.O. Box 668, Zanzibar, Tanzania c Department of Biological and Marine Sciences, Marian University College, P.O. Box 47, Bagamoyo, Pwani, Tanzania ARTICLE INFO ABSTRACT Keywords: Investigation on accumulation of selected heavy metals of Zinc, Mercury, Copper, Lead, Chromium and Nickel in Bio-accumulation sediment, water and muscle tissues of Clarias gariepinus (African catfish) and Oreochromis esculentus (Singida Fisher folk tilapia) fish was done in Lake Rukwa, Tanzania. Samples were obtained from transects of 100 m long extending fi Cat sh from Luika and Songwe River mouths to offshore.
    [Show full text]
  • Morphological Development of Embryos and Juveniles in the Mozambique Tilapia, Oreochromis Mossambicus As a Direct Developmental Fish Under Rearing Conditions
    SUISANZOSHOKU 51(3), 295-306 (2003) Morphological Development of Embryos and Juveniles in the Mozambique Tilapia, Oreochromis mossambicus as a Direct Developmental Fish under Rearing Conditions Katsunori TACHIHARA*1,2 and Emi OBARA*1 (Accepted June 17, 2003) Abstract: The Mozambique tilapia, Oreochromis mossambicus is one of the species introduced to Okinawa Island. This species breeds widely in the rivers of the island. In order to understand the biological aspects of O. mossambicus under the natural conditions of the island, a detailed observa- tion of early morphological development was done under rearing conditions. The development of O . mossambicus was studied; it consisted of an embryonic phase of approximately 88 hours and 30 minutes, a free embryonic phase of about 12 days, followed by the juvenile period. The embryo became free-swimming on the sixth day of the free embryonic phase. The osteological develop- ment using enzyme-cleared specimens indicated that after reaching the juvenile stage, develop- ment of almost basic bones was complete 25 days after hatching. Key words: Oreochromis mossambicus; Direct development; Early life history; Okinawa Island The Mozambique tilapia, Oreochromis mos- sambicus is a freshwater fish, which has been Materials and Methods introduced to Okinawa Island1-3). The species is endemic to southern African rivers, lagoons Three mouthbreeding females (122.7 to and lakes, and ranges from the lower Zambezi 124.7 mm in standard length) harboring newly system in the north to the Bushmans River fertilized ova were collected from the Onaha in the south4). This species was introduced to River, Nishihara, Okinawa, Japan, on June 4, Okinawa Island in 1954 from Taiwan as a source 1997, using a cast net (mesh size: 1•~1 cm).
    [Show full text]
  • A BIBLIOGRAPHY of IMPORTANT TILAPIAS (PISCES: CICHLIDAE) for AQUACULTURE Oreochromisvariabilis, 0 Andersoni, 0
    AMV'__ BIBLIOGRAPHIES 6 A BIBLIOGRAPHY OF IMPORTANT TILAPIAS (PISCES: CICHLIDAE) FOR AQUACULTURE Oreochromisvariabilis, 0 andersoni, 0. esculentus, 0. leucostictus, 0. rortimer, 0. spilurus niger,Sarotherodon melanotheron and Tilapia sparnmani PETER SCHOENEN INTERNATIONAL CENTER FOR LIVING AQUATIC RESOURCES MANAGEMENT A BIBLIOGRAPHY OF IMPORTANT TILAPIAS (PISCES: CICHLIDAE) FOR AQUACULTURE Oreochromls variabilis, 0. andersoni, 0. esculentus, 0. leucostictus, 0. mortimeri, 0. spilurus niger, Saro therodon melano theron and Tilapia sparrmanii Peter Schoenen International Collection "Cichlid Papers" The Referencc Service Parkstr. 15 D-5176 Inden 4 Federal Republic of Germany 1985 INTERNATIONAL CENTER FOR LIVING AQUATIC RESOURCES MANAGEMENT MANILA, PHILIPPINES A bibliography of important tilapias (Pisces: Cichlidae) for aquaculture Oreochromis variabilis, 0. andersonii, 0. esculentus, 0. leucostictus, 0. mort/tmer, 0. spilunis niger, Sarotherodon melanothero,, ard -/ilapiasparrmanii PETER SCHOENEN Published by the International Center for Living Aquatic Resources Management, MCC P.O. Box 1501, Makati, Metro Manila, Philippines with financial assistance from the International Development Research Centre of Canada through ICLARM's Selective Information Service project. 1985 Printed in Manila, Philippins This bibliography is produced directly from the author's manuscript in oider to provide tilapia workers with a useful document in the shortest time. The author should be consulted in the event of difficulty ir verifying details of particular references or in locating sources. ISSN 0115-5997 ISBN 971-1022-19-2 Schoenen, P. 1985, A bibliography of important tilapias (Pisces: Cichlidae) for aquaculture Oreochromis variabilis, 0. andersonii, 0. esculentus, 0. leucostictus, 0. mortimeri, 0. spilurut niger, Sarotherodon mela. notheron and Tilapia sparrrnanii. ICLAHM Biblio­ graphies 6,99 p. International Center for Living Aquatic Resources Management, Manila, Philippines.
    [Show full text]
  • Implications for Management AFRICAN GREAT LAKES
    AFRICAN GREAT LAKES CONFERENCE 2nd – 5th MAY 2017, ENTEBBE, UGANDA Dynamics of Fish Stocks of Commercial Importance in Lake Victoria, East Africa: Implications for Management Robert Kayanda, Anton Taabu-Munyaho, Dismas Mbabazi, Hillary Mrosso, and Chrisphine Nyamweya INTRODUCTION • Lake Victoria with a surface area of 68,800 sqkm is the world’s second largest freshwater body • It supports one of the world’s most productive inland fisheries with the estimated total fish landings from the lake for the period of 2011 to 2014 have been about 1 million tons with a beach value increasing from about US$ 550 Million in 2011 to about US$ 840 million in 2014. • It supports about 220,000 fishers (Frame Survey 2016) • The fish stocks of Lake Victoria have changed dramatically since the introduction of Nile perch Lates niloticus during the late 1950s and early 1960s Fishery Haplochromines The Original Fish Fauna Brycinus sp Protopterus Rastrineobola Mormyrus spp Barbus spp Bagrus docmac Labeo Schilbe intermedius Oreochromis variabilis Clarias gariepinus Mormyrus spp Synodontis victoriae Oreochromis leucostictus INTRODUCTION Currently, the fisheries is dominated by four major commercial important species, these are; •Nile perch •Dagaa •Nile tilapia •Haplochromis Apart from Nile tilapia only estimated through trawl and catch surveys, the other 3 are estimated through trawl, acoustics, and catch INTRODUCTION This paper summarizes current knowledge of the status of the fish stocks and reviews the need for species specific management plans for the major commercial important fish species of Lake Victoria (Nile perch, Nile tilapia, dagaa and haplochromines). Methods • Fisheries dependent – Frame surveys – Catch assessment surveys • Fisheries independent – Acoustic – Bottom trawl Biomass and relative abundance • Total biomass from the surveys 3500 remained fairly stable over time.
    [Show full text]
  • Mozambique Tilapia)
    UWI The Online Guide to the Animals of Trinidad and Tobago Behaviour Oreochromis mossambicus (Mozambique Tilapia) Family: Cichlidae (Cichlids and Tilapias) Order: Perciformes (Perch and Cichlids) Class: Actinopterygii (Ray-finned Fish) Fig. 1. Mozambique tilapia, Oreochromis mossambicus. [http://ja.wikipedia.org/wiki/%E3%83%95%E3%82%A1%E3%82%A4%E3%83%AB:Oreochromis_mossambicus_ by_NPS.jpg, downloaded 5 October 2012] TRAITS. Oreochromis mossambicus is a medium sized, laterally compressed fish that has long dorsal fins with 10-13 rays and spines (Froese & Pauly 2007). Its scales are large along the snout and fore head and become smaller along the body (Luna 2012). The coloration is a dull greenish yellow with weak banding pattern along the body (Froese & Pauly 2007). The adults range in size from 25 cm in the female to approximately 35 cm in the male. The male has an average weight of 2.5 pounds and the female ranges from 1.8-2 pounds at its maximum weight (Froese & Pauly 2007). O. mossambicus exhibits sexual dimorphism, the best descriptors are the premaxilla width, anal fin height and snout length; traits vital for agonistic displays, nesting and fighting (Oliveira & Almeda 1995). The size and coloration vary in captivity and with its diet. Some O. mossambicus look almost black in colour; females, non-breeding males and fry/ juveniles have a silvery colour on the scales (Luna 2012). O. mossambicus can live in both brackish and salt water and can survive a wide range of temperatures (Froese & Pauly 2007), and can live up to 11 years (Luna 2012). UWI The Online Guide to the Animals of Trinidad and Tobago Behaviour ECOLOGY.
    [Show full text]
  • Blackchin Tilapia (Sarotherodon Melanotheron) Ecological Risk Screening Summary
    U.S. Fish and Wildlife Service Blackchin Tilapia (Sarotherodon melanotheron) Ecological Risk Screening Summary Web Version – 10/01/2012 Photo: © U.S. Geological Survey From Nico and Neilson (2014). 1 Native Range and Nonindigenous Occurrences Native Range From Nico and Neilson (2014): “Tropical Africa. Brackish estuaries and lagoons from Senegal to Zaire (Trewavas 1983).” Nonindigenous Occurrences From Nico and Neilson (2014): “Established in Florida and Hawaii. Evidence indicates it is spreading rapidly in both fresh and salt water around island of Oahu, Hawaii (Devick 1991b).” “The first documented occurrence of this species in Florida was a specimen gillnetted by commercial fishermen in Hillsborough Bay near Tampa, Hillsborough County, in 1959 (Springer and Finucane 1963). Additional records for the western part of the state indicate that this species is established in brackish and freshwaters in eastern Tampa Bay and in adjoining drainages in Hillsborough County, ranging from the Alafia River south to Cockroach Bay. The species has been recorded from the Alafia River from its mouth up to Lithia Springs; from the Hillsborough River, Bullfrog Creek, the Palm River, and the Little Manatee River; and from various western drainage and irrigation ditches (Springer and Finucane 1963; Finucane and Rinckey 1967; Buntz Sarotherodon melanotheron Ecological Risk Screening Summary U.S. Fish and Wildlife Service – Web Version – 10/01/2012 and Manooch 1969; Lachner et al. 1970; Courtenay et al. 1974; Courtenay and Hensley 1979; Courtenay and Kohler 1986; Lee et al. 1980 et seq.; Courtenay and Stauffer 1990; DNR collections; UF museum specimens). There are two records of this species from the west side of Tampa Bay, in Pinellas County: a collection from Lake Maggiore in St.
    [Show full text]
  • Relation of Desert Pupfish Abundance to Selected Environmental Variables
    Environmental Biology of Fishes (2005) 73: 97–107 Ó Springer 2005 Relation of desert pupfish abundance to selected environmental variables in natural and manmade habitats in the Salton Sea basin Barbara A. Martin & Michael K. Saiki U.S. Geological Survey, Biological Resources Division, Western Fisheries Research Center-Dixon Duty Station, 6924 Tremont Road, Dixon, CA 95620, U.S.A. (e-mail: [email protected]) Received 6 April 2004 Accepted 12 October 2004 Key words: species assemblages, predation, water quality, habitat requirements, ecological interactions, endangered species Synopsis We assessed the relation between abundance of desert pupfish, Cyprinodon macularius, and selected biological and physicochemical variables in natural and manmade habitats within the Salton Sea Basin. Field sampling in a natural tributary, Salt Creek, and three agricultural drains captured eight species including pupfish (1.1% of the total catch), the only native species encountered. According to Bray– Curtis resemblance functions, fish species assemblages differed mostly between Salt Creek and the drains (i.e., the three drains had relatively similar species assemblages). Pupfish numbers and environmental variables varied among sites and sample periods. Canonical correlation showed that pupfish abundance was positively correlated with abundance of western mosquitofish, Gambusia affinis, and negatively correlated with abundance of porthole livebearers, Poeciliopsis gracilis, tilapias (Sarotherodon mossambica and Tilapia zillii), longjaw mudsuckers, Gillichthys mirabilis, and mollies (Poecilia latipinna and Poecilia mexicana). In addition, pupfish abundance was positively correlated with cover, pH, and salinity, and negatively correlated with sediment factor (a measure of sediment grain size) and dissolved oxygen. Pupfish abundance was generally highest in habitats where water quality extremes (especially high pH and salinity, and low dissolved oxygen) seemingly limited the occurrence of nonnative fishes.
    [Show full text]