LIFE HISTORY STRATEGY PATTERNS OF SELECTED FISH SPECIES OF THE KUJA- MIGORI RIVER BASIN IN SOUTH WEST KENYA
Abstract
Fish life history strategies are complex patterns of co-evolved traits for a given aquatic ecosystem. Fish life history strategies are responsible on the way fish populations respond to environmental changes. The information obtained from studies on life history strategies is important in the ecosystem approach to fisheries management. The objective of this study will be to describe various life history strategies of three fish species in the Kuja - Migori river system. A study will be conducted in the Kuja - Migori river basin on life history strategies and related environmental factors for three fish species namely; Barbus altianalis, Labeo victorianus and Brycinus sardileri.
Fish specimens will be collected from 5 sampling sites from the Kuja-Migori river system. Data to determine fish life history strategies for three species will be collected on the following variables: size at maturity (at 50% maturity), age at maturity, total instantaneous mortality, maximum size, fecundity, frequency of spawning, maximum age, egg size. Analysis on the relationship between life history strategies of the fishes and environmental variables will be conducted in the Kuja -Migori system. Information obtained from this
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For instance, the strategy of fish to produce a maximum number of young ones in order to cope with changes in environmental parameters will result to variable recruitment, which will in future contribute to variable annual yields. Fish life history strategies are responsible for responses of fish population to environmental changes. The information obtained from studies on life history strategies is important in the ecosystem approach to fisheries management as compared to the classical single species assessment methods (Olden and Julian
13. Species Summary for Etheostoma nianguae: Niangua darter. Page, L.M. and B.M. Burr,1991. (On-line) http://www.fishbase.org/Summary/SpeciesSummary.cfm?ID=3444
In this entertaining, search into global fish hatcheries, New York Times writer Paul Greenberg investigates our historical connection with the ever changing ocean and the wild fish within it. In the beginning of the book Paul is telling his childhood fishing stories to his friends, that night Paul discovers that that four fish dominate the world’s seafood markets in which are salmon, tuna, cod, and bass. He tries to figure out why this is and the only logical answer he could come up with is that four epochal shifts caused theses wild fish population to diminish. History shows that four epochal shifts happen within fifteen years causing certain fish species populations to diminish. He discovers for each of the four fish why this happened to
Since three-forth of the world is composed of bodies of water, it’s natural that a great number of people rely on fishing for their livelyhood or just for their recreation needs. There are numerous of fish species swimming under the lakes, seas, ponds, and rivers. Most anglers consider fishing as the delight in their purpose-driven life, a sport, as they say.
Fish habitat is the underwater world which many people do not see. It is just like the world that people live. Fish and plants reproduce, eat, and live in this environment, and even face challenges such as invasive species. It is said that “Invasive species are non-native species that threaten the diversity or abundance of native species due to their uncontrollable population growth, causing ecological or economic impacts” (“Invasive” par. 1). Vegetation plays a big role for fish habitat and for a lake itself. Aquatic habitat provides living space for not only fish but also for many aquatic insects. These insects then in turn provide fish and other species of animals with food (“Native” par. 4).
Soule, Michael E et al. “Ecological Effectiveness: Conservation Goals for Interactive Species.” Conservation Biology 17.5 (2003) : 1238-1250.
Introduction: The common carp, Cyprinus carpio is a widespread freshwater fish that belongs to the minnow family “Cyprinidae”. This species is a relatively large species with weights which range from 2-14 kg. The life span of common carp in the wild is up to 20 years. Originally, common carp is native to Europe and Asia and is now the most domesticated and cultivated carp species throughout the world.
About half of the fish species live in groups at some point in their life
The salmon fishing industry has exploited the fish for centuries. Records of the White and Barents Seas, Northern Russia, salmon catch from the 17th Century through the 20th Century show increased exploitation and the inevitable decline of biomass (Lajus et al., 2007). In Podporozh’e weir 387 salmon were caught annually at the end of the 17th Century while 1947 fish were caught annually in the beginning of the 20th Century. Similar catch was recorded in Podporozh’e district with 560 fish annually in the 17th Century and 1544 fish annually in the beginning of the 20th Century. Catch from the Onega River illustrates even more exploitation with 848 fish annually in the 17th Century compared to 2586 fish and 3141 fish annually in the 17th Century, 1820s, and beginning of the 20th Century respectively. The catches gradually decreased in numbers after the beginning of the 20th Century due to overfishing and the introduction of the timber industry to the area. The size of the fish had dropped over this span of time from an average weight of 8.09kg in the early 17th Century to 6.72kg in the beginning of the 20th Century. In 2002 the weight had gotten even smaller with an average of 4.2kg. The Varzuga district had catch values that were even more alarming with 25,151 fish caught in the 18th Century increasing to 58,484 fish the late 19th and early 20th Centuries. However, despite the amount of fish taken from the Varzuga River the population seems stable. The Varzuga River is one of the most productive salmon rivers in the world. The ability of this river to support the large harvest is believed to be due to its lack of natural resources in the area and the remoteness keeps human populations down and makes getting to the area di...
One should not think that because zebrafish (Danio rerio) are fishes that they are in some ways less than any mammalian species. They certainly are not. Zebrafish are small shoaling cyprinids, named after the prominent black and white stripes patterns of the adults. Native to the Indian subcontinent, those laterally compressed organisms are widely distributed in slow moving streams and stagnant habitats. Where existent, zebrafish are typically the most abundant species (McClure, et al., 2006, p. 562). They also have a short generation time which allows large numbers to hatch in a short period of time. The species has become popular among enthusiasts due to its hardiness, cold resistance, and facility of breeding. Over the years, selective breeding have created numerous different strands.
This time period is actually beneficial in most aspects of stream animal (vertebrate and invertebrate) health
Stewart, B. S., and S. G. Wilson. 2005. Threatened fishes of the world: Rhincodon typus (Smith 1828) (Rhincodontidae). Environ. Bio Of. Fishes. 74:184-185. (DOI:10.1007/s10641-005-2229-1).
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First, across Africa the landscape is changing, the snowy caps of Mount Kilimanjaro are melting and the shorelines of Lake Chad are receding. The once enormous Lake Chad has nearly vanished, it is now half the size it was thirty five years ago (Offor, 2008). The town of Burundi is on Lake Tanganyika, which is still a vast expanse of water, but the shoreline has retreated 50 feet in the last 4 years, and ships can no longer reach the port. Lake Victoria, the biggest of Africa's great lakes, dripped by a vertical inch a day for much of last year. The receding of these lakes along with a change in temperature of the water will now deplete the fish stock. As the fish sources decrease, this limits the amount of fish caught and sold by fisherman. When the regular food source is strained, Africans may turn to hunting wil...