DOCSLIB.ORG

New Distributional Record of the Endemic Estuarine Sand Whiting, Sillago Vincenti Mckay, 1980 from the Pichavaram Mangrove Ecosystem, Southeast Coast of India

Total Page：16

File Type：pdf, Size：1020Kb

Download full-text PDF Read full-text
New Distributional Record of the Endemic Estuarine Sand Whiting, Sillago Vincenti Mckay, 1980 from the Pichavaram Mangrove Ecosystem, Southeast Coast of India Indian Journal of Geo Marine Sciences Vol. 47 (03), March 2018, pp. 660-664 New distributional record of the endemic estuarine sand whiting, Sillago vincenti McKay, 1980 from the Pichavaram mangrove ecosystem, southeast coast of India Mahesh. R1δ, Murugan. A2, Saravanakumar. A1*, Feroz Khan. K1 & Shanker. S1 1CAS in Marine Biology, Faculty of Marine Sciences, Annamalai University, Porto Novo, Tamil Nadu, India - 608 502. 2Department of Value Added Aquaculture (B.Voc.), Vivekananda College, Agasteeswaram, India - 629 701. δ Present Address: National Centre for Sustainable Coastal Management, MoEF & CC, Chennai, India - 600 025. *[E-mail: [email protected]] Received 27 December 2013 ; revised 17 November 2016 The Sillaginids, commonly known as sand whiting are one among the common fishes caught by the traditional fishers in estuarine ecosystems all along the Tamil Nadu coast. The present study records the new distributional range extension for Sillago vincenti from the waters of Pichavaram mangrove, whereas earlier reports were restricted to only the Palk Bay and Gulf of Mannar regions of the Tamil Nadu coast, whereas it enjoys a wide range of distribution both in the east and west coast of India. This study marks the additional extension of the distributional record for S. vincenti in the east coast of India. Biological information on these fishes will have ecological applications particularly on account on their extreme abundance in the mangrove waters. The present study is based on the collection of specimens from handline fishing practices undertaken in the shallow waters of Pichavaram mangroves, on the southeast coast of India. [Keywords: Sillagnids, Sillago vincenti, Pichavaram, India] Introduction Sillaginopodys and Sillaginops)8. In Indian Estuarine sand whiting, Sillago vincenti waters they are distributed both along the east McKay, 1980 belongs to the order Perciformes and west coast9,10,11,12 in various ecosystems representing the family Sillaginidae, locally which suggest the stenohaline adaptation of called as “Keelaikan” in Tamil. These fishes these fishes. As per the available literature usually inhabitant the shallow waters of around 13 valid species (Sillaginopodys brackish water ecosystems with a preference for chondropus, Sillaginopsis panijus, Sillago sandy substrata1,2. Globally, most of the species aeolus, S.argentifasciata, S.ingenuua, belonging to the family Sillaginidae are S.intermedius, S.indica, S.lutea, S.maculata, distributed in tropical and subtropical S.sihama, S.soringa, S.vincenti and S.vittata) regions1,2,3,4,5 while some species are distributed have been reported from Indian in temperate waters6,7. Around 34 species of waters11,13,14,15,16,17,18,19,20,21. Sillaginid species fishes belonging to the family Sillaginidae have have been considered as a candidate species for been recorded worldwide, which comprised of 5 brackish water aquaculture in Asia and India genus (Sillago; Sillaginopsis; Sillaginodes, MAHESH et al.: ENDEMIC ESTUARINE SAND WHITING, SILLAGO VINCENTI MCKAY, 1980 661 making them an economically important and a the head has a golden tinge and each eye has a 22 preferred food species . silver iris with a golden outer surface (Fig. 2 (a)). The snout has a dusky tinge and the Materials and Methods operculum is dark yellow to golden colour. The Fishes were caught by handlines operated by fins are hyaline, with two discontinuous dorsal fishermen in the shallow waters of Pichavaram fins, where first dorsal fin consists of 11 spines o o mangroves (Lat: 11 26.04'N; Long: 79 47.82'E) and the second dorsal fin consists of 1 spine, (Fig. 1) during July, 2012. The freshly captured followed by 23 soft rays and they bear distinct fishes (n=2), from the shallow waters, dark spots, running parallel, closer to each spine approximately 2m depth on a sandy bottom and ray shown in Fig. 2(b) and (c). The anal fin (near the estuarine mouth region) were collected is milky white with white tips which consist of 2 for the present study. spines and 24 soft rays. The pectoral fin base is golden yellow and the pelvic fin is white with a yellowish tip. There are minute discrete black spots present on the flanks of the lateral line shown in Fig. 2(c). In the case of the swim bladder outer morphology, a short bulbous projection was present anteriorly with three anterolateral lobate or recurved projections and no anterior extensions from the swim bladder but, a post coelomic extension present posteriorly with a duct like process on the ventral surface that continues to the vent shown in Fig. 2(d) and (e). They have 34 vertebrae and 74 scales on the lateral line. Five rows of scales are present between the base of the first dorsal- Fig. 1 - Map showing sampling area, Pichavaram, fin spine and lateral line. The maximum length Southeast coast of India. of the fish species from the present study was 9 The fishes were photographed and identified 17.1 cm. However, it can grow up to 30 cm . based on their morphometric, meristic and swim The present results are similar to earlier results 24 bladder characteristics22,,23,24. which recorded a length of 158 to 308mm . Results and Discussions Present study is based on detail study of two specimens of Sillago vincenti from the Pichavaram mangrove ecosystem, in the southeast coast of India. Though this species is closely related to other species like Sillago sihama; S. soringa; S. boutani of the same genus, it can be distinguished by the following characters such as, minute black dots on flanks below the lateral line, pigmentation on dorsal fins, number of rows of scales between the base of the first dorsal-fin spine and the lateral line, Fig. 2 - Sillago vincenti (McKay 1980) with dark black number of vertebrae, and importantly, its swim spots in first and second dorsal fin and its swim bladder bladder structure which consists of one post- structure 25 coelomic extension . The morphometric measurements and meristic From the present observation, the body and head values of the study specimens are presented in colour of the S. vincenti are sandy to light olive; 662 INDIAN J. MAR. SCI., VOL. 47, NO. 03, MARCH 2018 Table 1. Around three fish species belonging to Kakinada and Visakhapatnam waters10. the family Sillaginidae viz., Sillago domina, S. Recently two more species viz., S. aeolus and S. sihama and S. maculate where reported for the ingenuua was based on collections made from first time from Indian waters12. Later S. vincenti Mallipattinam waters17. was reported for the first time in India waters from its observation from Kavand, near The distributional range extension of S. vincenti Neendakara, north of Quilon, Kerala State, India in Indian waters has been reported from the 26 27 20. Afterwards seven species of Sillaginidae coast of Kerala , Karnataka , former Andhra 28 5 29,30 family (S. paryisouamis, S. macrolepis, Pradesh , Goa and Tamil Nadu . In the case S. maculata, S. argentifasciata, Sillaginopodys of the Pichavaram mangrove waters, which are 31 chandropus and Sillaginopis panijus) were rich in ichthyofauna diversity , where S. sihama 32 accounted from the Indian coast13. Subsequently is already reported and the observation of two more species namely S. soringa and S.vincenti adds to existing sand whiting S. intermedius were recorded from Chennai, diversity here. Table 1 Morphometric measurements and meristic characteristics of S.vincenti (McKay, 1980) from present study Morphometric characters value Specimen I Specimen II (mm) (mm) Total length 171 117 Standard length 149 113 Head length 48 31 Body depth 22 17 Pre orbital length 18 13 Post orbital length 17 10 1st dorsal fin base length 34 21 2nd dorsal fin base length 57 38 Pectoral fin length 22 15 Pelvic fin length 19 18 Anal fin length 46 37 Caudal fin length 22 19 1st dorsal fin spine length 31 19 2nd dorsal fin spine length 30 18 3rd dorsal fin spine length 28 17 4th dorsal fin spine length 24 16 11th dorsal fin spine length 4 4 Pectoral base length 6 5 Pelvic base length 5 3 Anal base length 52 37 Caudal peduncle length 27 18 Caudal peduncle depth 8 4 Eye diameter 7 5 Inter nasal width 5 4 Head depth 28 19 Upper jaw length 6 5 Lower jaw length 5 4 Meristic characters Number of branchiostegal rays 3 3 Number of 1st dorsal spines 11 11 Number of 2nd dorsal spine 1 1 Number of 2nd dorsal soft rays 23 23 Number of pectoral soft rays 15 15 MAHESH et al.: ENDEMIC ESTUARINE SAND WHITING, SILLAGO VINCENTI MCKAY, 1980 663 Number of pelvic soft rays 6 6 Number of anal spine rays 2 2 Number of anal soft rays 24 24 Number of rows of scales between base of first dorsal-fin 5 5 spine and lateral line Number of scales on lateral line 74 74 Number of vertebrae column 34 34 Number of post-coelomic extension in 1 1 swim bladder Some research studies claims that S.vincenti is 6. Celand K. W., Studies on the Economic Biology 33 of the Sand whiting (Sillago ciliate, C. & V). endemic to Indian waters , whereas the Proceedings of the Linnaeus Society of New observation of its occurrence has been reported South Wales. 72 (1947) 215 - 228. from Sri Lankan waters25, which suggest its 7. Hayward C. J., Distribution of External Parasites Indicates Boundaries to Dispersal of Sillaginid occurrence in the Sri Lankan part of the Gulf of Fishes in the Indo-West Pacific. Mar. Mannar or that is shared by waters of both Freshwater Res., 48 (1997) 391 - 400. 8. Froese, R. & Pauly, D. 2017. Fish Base (version nations. Although there are several reports on 10/2017). Available at www.fishbase.org the fish diversity31,32, the present record of S.
Load more

Recommended publications
  • Short Nosed Sturgeon
    Connecticut River Coordinator's Office: Fish Facts - Shortnose Sturgeon Page 1 of 3 Skip navigation links Fish Facts - Shortnose Sturgeon z Description z Life History z Distribution z Status z Restoration Efforts Download a Fact Sheet (85 KB Adobe pdf file) You will need Adobe Acrobat Reader software to open the document above. If you do not have this software, you may obtain it free of charge by following this link. Description The shortnose sturgeon (Acipenser brevirostrum) is one of two sturgeon species in the Connecticut River; the other is the Atlantic sturgeon. The shortnose is the smaller of the two, growing to be 2 to 3 feet in length and about 14 pounds in weight. Sturgeons are an ancient species with fossils dating back 65 million years. They are very distinctive, looking like a prehistoric cross between a shark and a catfish. Sturgeons lack teeth and scales but have a unique body armor of diamond-shaped bony plates called scutes. Some have been found to be over 60 years old. Life History Shortnose sturgeon are typically anadromous, migrating from the ocean to fresh water specifically to reproduce. However, of the two populations in the Connecticut River system (formed by the construction of dams), one is considered to be partially landlocked and the other is likely to be http://www.fws.gov/r5crc/Fish/zf_acbr.html 1/3/2007 Connecticut River Coordinator's Office: Fish Facts - Shortnose Sturgeon Page 2 of 3 amphidromous, moving between fresh and salt water. Shortnose reproduce in the spring. They broadcast their eggs in areas with rubble substrate.
    [Show full text]
  • And Brackish Water Environments What Is Brackish Water Brackish Water Is Water Which Contains More Sea Salts Than Freshwater but Less Than the Open Sea
    http://www.unaab.edu.ng COURSE CODE: FIS316 COURSE TITLE: Marine and Brackishwater Economic Resources NUMBER OF UNITS: 2 Units COURSE DURATION: Two hours per week COURSECOURSE DETAILS:DETAILS: Course Coordinator: Prof. Yemi Akegbejo‐Samsons Email: [email protected] Office Location: Room D210, COLERM Other Lecturers: Dr. D.O. Odulate COURSE CONTENT: Study of major marine and brackish water fin and shell fish species in relation to their development for culture, food and industrial uses. Methods of harvesting e.g. electro‐ fishing. COURSE REQUIREMENTS: This is a compulsory course for all students in Department of Aquaculture & Fisheries Management. In view of this, students are expected to participate in all the course activities and have minimum of 75% attendance to be eligible to write the final examination. READING LIST: E LECTURE NOTES 1. Study of major marine and brackish water fin and shell fish species in relation to their development for culture, food and industrial uses. 2. Methods of harvesting e.g. electro-fishing. This course is taught by Prof Yemi Akegbejo-Samsons and Dr D O Odulate. The venue for the interaction with students is on the ground floor of the College of Environmental Resources Management. Topic 1 Marine and Brackish water environments What is Brackish Water Brackish water is water which contains more sea salts than freshwater but less than the open sea. http://www.unaab.edu.ng Moreover, brackish water environments are also fluctuating environments. The salinity is variable depending on the tide, the amount of freshwater entering from rivers or as rain, and the rate of evaporation.
    [Show full text]
  • Caspian Sea, Estuarine, Zooplankton, Diversity, Physicochemical
    Advances in Life Sciences 2014, 4(3): 135-139 DOI: 10.5923/j.als.20140403.07 The Influence of Salinity Variations on Zooplankton Community Structure in South Caspian Sea Basin Estuary Maryam Shapoori1,*, Mansoure Gholami2 1Department of Fishery, College of Natural resources, Savadkooh Branch, Islamic Azad University, Savadkooh, Iran 2Department of Fishery, College of Natural resources, Sanandaj Branch, Islamic Azad University, Sanandaj, Iran Abstract In order to better understanding the impact of changes in salinity on zooplankton community structure, investigations on the physicochemical characteristics, phytoplankton, and zooplankton component of an estuarine zone in South-Eastern Caspian Sea was carried out for one year between March, 2011 and July, 2012. The study showed notable seasonal variation in the components investigated. Salinity and water flow rate regime seemed a major determinant of the composition, abundance and seasonal variation of encountered estuarine biota. Rain events associated with reducing salinities and inflow associated with decreasing salinities may be key hydro-meteorological forcing operating in the estuary. The collection of juvenile forms (Zooplankton) recorded probably points to the suitability of the estuary characteristics to serve as breeding ground and place of refuge for diverse aquatic species. Keywords Caspian Sea, Estuarine, Zooplankton, Diversity, Physicochemical levels within coastal aquatic ecosystems in south Caspian 1. Introduction Sea region. Salinity is amongst the most important environmental factors with the potential to significantly River mouths are common hydrological features of South- influence estuarine communities [11]. Therefore, Eastern features of Caspian Sea and form part of the fluctuations in salinity and other environmental factors (e.g. numerous ecological niches associated with the Caspian temperature, pH, nutrients and pigments) on both spatial and coastal environment.
    [Show full text]
  • Shortnose Sturgeon Fact Sheet
    Shortnose Sturgeon Acipenser brevirostrum Description: Facts: olive-yellow to gray or bluish on the back listed as endangered, it is unlawful to kill or possess this fish milky white to dark yellow on the belly long lived, like most sturgeon 5 rows of pale bony plates, called scutes males spawn every other year, females spawn every (one on the back, two on the belly and one on each third year side) semi anadromous (migrates from salt water to spawn scutes are pale and contrast with background in fresh water) 4 barbels in front of its large underslung mouth eat sludge worms, insect larvae, plants, snails, shrimp and crayfish short blunt conical snout use barbels to locate food Size: rarely exceeds 3.5 feet and 14 pounds SHORTNOSE STURGEON CATCH TOTALS Year Total 2004 1 Range: Grand Total 1 Atlantic seaboard in North America, from the St. *shortnose sturgeon were only caught during the John’s River in New Brunswick to the St. John River years shown in Florida NJ Department of Environmental Protection Division of Fish and Wildlife Bureau of Marine Fisheries www.NJFishandWildlife.com Shortnose Sturgeon Acipenser brevirostrum Historically, the Delaware Estuary has been an important habitat for two species of sturgeon: the shortnose sturgeon, and its cousin, the Atlantic sturgeon. Atlantic sturgeon primarily live in the ocean, and migrate through the estuary to spawn in freshwater. Shortnose sturgeon spend most of their time in the brackish water of the estuary, moving upstream to fresher water to spawn. Over the duration of the Delaware River seine survey, only one sturgeon has ever been caught.
    [Show full text]
  • Comparisons Between the Biology of Two Species of Whiting (Sillaginidiae) in Shark Bay, Western Australia
    Comparisons between the biology of two species of whiting (Sillaginidiae) in Shark Bay, Western Australia By Peter Coulson Submitted for the Honours Degree of Murdoch University August 2003 1 Abstract Golden-lined whiting Sillago analis and yellow-fin whiting Sillago schomburgkii were collected from waters within Shark Bay, which is located at ca 26ºS on the west coast of Australia. The number of circuli on the scales of S. analis was often less than the number of opaque zones in sectioned otoliths of the same fish. Furthermore, the number of annuli visible in whole otoliths of S. analis was often less than were detectable in those otoliths after sectioning. The magnitude of the discrepancies increased as the number of opaque zones increased. Consequently, the otoliths of S. analis were sectioned in order to obtain reliable estimates of age. The mean monthly marginal increments on sectioned otoliths of S. analis and S. schomburgkii underwent a pronounced decline in late spring/early summer and then rose progressively during summer and autumn. Since these trends demonstrated that opaque zones are laid down annually in the otoliths of S. analis and S. schomburgkii from Shark Bay, their numbers could be used to help age this species in this marine embayment. The von Bertalanffy growth parameters, L∞, k and to derived from the total lengths at age for individuals of S. analis , were 277 mm, 0.73 year -1 and 0.02 years, respectively, for females and 253 mm, 0.76 year -1 and 0.10 years, respectively. Females were estimated to attain lengths of 141, 211, 245 and 269 mm after 1, 2, 3 and 5 years, compared with 124, 192, 224 and 247 mm for males at the corresponding ages.
    [Show full text]
  • MODULE 1 Choice of Species Goa Ls
    MODULE 1 Choice of Species Goa ls • To provide the trainees with the knowledge to have a better understanding about the criteria used for species selection for culture. • Make trainees aware of what are the options available in the Caribbean for culture. Be aware of multiple species, local and Learning exotic options for Caribbean aquaculture. Objectives Be able to select possible species for culture based on th e crite ria ou tlin e d . What is Aquaculture? • Aquaculture, also known as aquafarming. • The farming of organisms in aquatic medium including fish, crustaceans, molluscs, aquatic plants, algae. • Aquaculture ranges from freshwater to saltwater populations under controlled conditions, and can be comparable to commercial fishing, which is the harvesting of wild fish. Criteria for Species Selection • It should be able to withstand the climate of the region in which it will be raised. • Its rate of growth must be sufficiently high. • It must be able to reproduce successfully under culture conditions. • It must accept and thrive on abundant and cheap artificial food. • It must be acceptable to the consumer. • It should support a high population density in ponds or tanks. • It must be disease -resistant. Most good aquaculture species are excellent aquatic Alien Invasive Species. Op tion al Sp ecies Su itab le for th e Carib b ean : Fish Grey mullet F= Fresh water, B= Brackish water, S= Salt water Op tion al Sp ecies Su itab le for th e Carib b ean : Fish American eel F= Fresh water, B= Brackish water, S= Salt water Op tion al Sp ecies
    [Show full text]
  • Brackish Water Community Tank
    Elmer’s Aquarium Community Tank Ideas Tank Size- 20 gal or more B rackish Water Community Tank What is a Brackish Water Tank? Brackish fish originate from areas in which freshwater and saltwater meet. Fish that have adapted to these areas typically can tolerate a wide range of salinities. Housing: Add 2-4 tablespoons of salt per gallon. We advise Seachem Brackish/Livebearer salt or Instant Ocean Marine salt. The salinity should be around 1.010 to 1.015. (The salinity of seawater is 1.025) . Keep pH 7.2-7.8. Use a marine substrate such as Aragonite sand to help maintain an alkaline pH. Maintain standard filtration and heating. Decor: Driftwood and plastic plants create hiding spots. It is a challenge to grow live plants in a brackish setup. If you want to try live plants use Java Fern. Mangrove Plants: Some interesting displays can be made with the use of Mangrove Plants. Feeding: Feed 2-3 times a day with standard foods a variety of quality foods. Use flake foods, frozen mysis shrimp, frozen bloodworms, Formula One, and plankton. Brackish Water Fish: Here is a list of some brackish water fish you may see at our store: Be sure to study the individual requirements when you are establishing your tank. Eels: Freshwater Moray Eel, ( Gymnothorax tile ) Gobies: Sand Sifting Sleeper Goby, Knight Goby, Dragonfish Goby, Bumblebee Goby, Purple Spot Goby. Others: Pike Livebearer (belonesox), Black Molly, Archer, Flounder. Cichlids: Orange Chromide. Puffers: (Typically kept in a species only tank) Spotted Puffer, Figure 8 Puffer, Fahaka Puffer Suitable for smaller tanks: (10 gal or more) Bumblebee Goby.
    [Show full text]
  • SAFS Report 2018
    STATUS OF AUSTRALIAN FISH STOCKS REPORT Sand Whiting (2018) Sand Whiting (2018) Sillago ciliata Jason McGilvray: Department of Agriculture and Fisheries, Queensland, Karina Hall: Department of Primary Industries, New South Wales STOCK STATUS OVERVIEW Jurisdiction Stock Fisheries Stock status Indicators Queensland Queensland ECIFFF Sustainable Commercial catch and CPUE, length and age, mortality rate New South Wales New South EGF, N/A, Sustainable Catch, effort and CPUE, Wales OHF length and age, mortality rate EGF Estuary General Fishery (NSW), N/A Not Applicable (NSW), OHF Ocean Hauling Fishery (NSW), ECIFFF East Coast Inshore Fin Fish Fishery (QLD) STOCK STRUCTURE Sand Whiting occur along the east coast of Australia and are most abundant in southern Queensland and northern New South Wales. Tagging studies have shown movement of adult fish between estuaries, but information on biological stock boundaries remains incomplete. The unknown nature of biological stock composition means no formal assessment of the entire biological stock has been completed. Separate assessments of Sand Whiting have been conducted in Queensland and New South Wales [Gray et al. 2000, Hoyle et al. 2000, Ochwada- Doyle et al. 2014, O’Neill 2000]. Here, assessment of stock status is presented at the jurisdictional level—Queensland and New South Wales. STOCK STATUS New South In New South Wales, Sand Whiting are mainly taken by the commercial Estuary Wales General Fishery (by the mesh netting and hauling sectors), with smaller catches reported by the Ocean Hauling Fishery [Hall 2015]. Annual commercial catches of Sand Whiting in NSW waters over the last five years have been well below the preceding 20 year average of 162 t [NSW DPI unpublished].
    [Show full text]
  • Catalogue of Protozoan Parasites Recorded in Australia Peter J. O
    1 CATALOGUE OF PROTOZOAN PARASITES RECORDED IN AUSTRALIA PETER J. O’DONOGHUE & ROBERT D. ADLARD O’Donoghue, P.J. & Adlard, R.D. 2000 02 29: Catalogue of protozoan parasites recorded in Australia. Memoirs of the Queensland Museum 45(1):1-164. Brisbane. ISSN 0079-8835. Published reports of protozoan species from Australian animals have been compiled into a host- parasite checklist, a parasite-host checklist and a cross-referenced bibliography. Protozoa listed include parasites, commensals and symbionts but free-living species have been excluded. Over 590 protozoan species are listed including amoebae, flagellates, ciliates and ‘sporozoa’ (the latter comprising apicomplexans, microsporans, myxozoans, haplosporidians and paramyxeans). Organisms are recorded in association with some 520 hosts including mammals, marsupials, birds, reptiles, amphibians, fish and invertebrates. Information has been abstracted from over 1,270 scientific publications predating 1999 and all records include taxonomic authorities, synonyms, common names, sites of infection within hosts and geographic locations. Protozoa, parasite checklist, host checklist, bibliography, Australia. Peter J. O’Donoghue, Department of Microbiology and Parasitology, The University of Queensland, St Lucia 4072, Australia; Robert D. Adlard, Protozoa Section, Queensland Museum, PO Box 3300, South Brisbane 4101, Australia; 31 January 2000. CONTENTS the literature for reports relevant to contemporary studies. Such problems could be avoided if all previous HOST-PARASITE CHECKLIST 5 records were consolidated into a single database. Most Mammals 5 researchers currently avail themselves of various Reptiles 21 electronic database and abstracting services but none Amphibians 26 include literature published earlier than 1985 and not all Birds 34 journal titles are covered in their databases. Fish 44 Invertebrates 54 Several catalogues of parasites in Australian PARASITE-HOST CHECKLIST 63 hosts have previously been published.
    [Show full text]
  • 20020011.Pdf
    Color profile: Generic CMYK printer profile Composite Default screen 1144 PERSPECTIVE Geological and evolutionary underpinnings for the success of Ponto-Caspian species invasions in the Baltic Sea and North American Great Lakes David F. Reid and Marina I. Orlova1 Abstract: Between 1985 and 2000, ~70% of new species that invaded the North American Great Lakes were endemic to the Ponto-Caspian (Caspian, Azov, and Black seas) basins of eastern Europe. Sixteen Ponto-Caspian species were also established in the Baltic Sea as of 2000. Many Ponto-Caspian endemic species are characterized by wide environmental tolerances and high phenotypic variability. Ponto-Caspian fauna evolved over millions of years in a series of large lakes and seas with widely varying salinities and water levels and alternating periods of isolation and open connections between the Caspian Sea and Black Sea depressions and between these basins and the Mediterranean Basin and the World Ocean. These conditions probably resulted in selection of Ponto-Caspian endemic species for the broad environmental tolerances and euryhalinity many exhibit. Both the Baltic Sea and the Great Lakes are geologi- cally young and present much lower levels of endemism. The high tolerance of Ponto-Caspian fauna to varying environmental conditions, their ability to survive exposure to a range of salinities, and the similarity in environmental conditions available in the Baltic Sea and Great Lakes probably contribute to the invasion success of these species. Human activities have dramatically increased the opportunities for transport and introduction and have played a cata- lytic role. Résumé : Entre 1985 et 2000, environ 70 % des espèces qui ont envahi pour la première fois les Grands-Lacs d’Amérique du Nord étaient endémiques aux bassins versants de la région pontocaspienne de l’Europe de l’Est, soit ceux de la mer Caspienne, de la mer d’Azov et de la mer Noire.
    [Show full text]
  • Fish Culture in Brackish Water
    Fish Culture in Brackish Water. Item Type Journal Contribution Authors Nzioka, R.M. Download date 01/10/2021 17:26:10 Link to Item http://hdl.handle.net/1834/7089 POST KENYA v.5 no. 2 May-August 1980 FISH CULTURE IN BRACKISH WATER R. M. Nzioka, Ketrya Marine and Fisheries Research Institute Introduction loose initial structure of the mud changes as moisture Brackish water is a mixture of fresh and salty water is diminished by evaporation and transpiration. The which usually occurs in estuaries, and has a salinity process of drying out results in the shrinking of the soil usually of between 15 and 30 per thousand, depending wItil it attains the proper physical character of pond on rainfall and freshwater run-off. barrier. Even though ponds very close to the shore are Some fish species like mullets are able to survive filled with undiluted seawater the great amount of rain­ in this environment. Most of the Mugi/idae shoal swim water trapped in the ponds during the monsoons, makes in or near the surface of the water and may be seen it not possible for salinity values equal or higher than jumping repeatedly in estuaries usually in the evenings. those of seawater to occur in the ponds at any time M. cepha/us and Liza aurata are potential species for other than during prolonged periods of drought. culture. These species occur in vast numbers and have very firm flesh of excellent flavour. They spawn in the Aquaculture tropics mostly from September to October. During this period they migrate away from estuaries.
    [Show full text]
  • 5 Brackish-Water Shrimp Cultivation Threatens Permanent Damage to Coastal Agriculture in Bangladesh
    5 Brackish-water Shrimp Cultivation Threatens Permanent Damage to Coastal Agriculture in Bangladesh Md. Rezaul Karim Urban and Rural Planning Discipline, Khulna University, Khulna, Bangladesh, e-mail: [email protected] Abstract Over the past 20 years, brackish-water shrimp cultivation in the coastal zone of Bangladesh has con- tributed increasingly to the national economy, but there is a lack of quantitative data on the effects of shrimp farming at the household and community levels. This chapter investigates the impact of shrimp cultivation on the environment and farmers’ livelihood in a typical subdistrict of the coastal zone in Bangladesh. The variables involved with shrimp cultivation and their impact on the land are also taken into consideration and an attempt is made to analyse the patterns of land-use change that occurred between 1975 and 1999. The extensive pattern of shrimp cultivation is achieved by expansion of area rather than by intensification. The expansion of shrimp farming has resulted in decreases in crop produc- tion and many environmental problems in the form of a shortage of livestock fodder, fuel scarcity and decreases in traditional labour forces. Under the present circumstances, shrimp cultivation is no doubt beneficial for a selected group of people, but it has negatively affected the livelihoods of landless and marginal farmers, making it difficult for them to survive in the area. Introduction Bagerhat), is one of the most promising areas for shrimp cultivation for two major reasons The Bangladesh coastal zone (Fig. 5.1) is a sig- (MOFL, 1997; Karim and Shah, 2001): first, its nificant maritime habitat of ecologically rich fresh- and saltwater resources are abundant and economically important natural resources.
    [Show full text]