Recruitment In Fish Populations Research Articles

David H. Cushing: Towards a Science of Recruitment in Fish Populations. Excellence in Ecology7, Ed. O. Kinne Ecology Institute, Oldendorf/Luhe 175 pp., 71 Figures, 6 Tables. ISSN 0932–2205 DM 58,‐

Internationale Revue der gesamten Hydrobiologie und HydrographieVolume 82, Issue 4 p. 563-563 Book Review David H. Cushing: Towards a Science of Recruitment in Fish Populations. Excellence in Ecology7, Ed. O. Kinne Ecology Institute, Oldendorf/Luhe 175 pp., 71 Figures, 6 Tables. ISSN 0932–2205 DM 58,- Hjalmar Thiel, Hjalmar ThielSearch for more papers by this author Hjalmar Thiel, Hjalmar ThielSearch for more papers by this author First published: 09 January 2007 https://doi.org/10.1002/iroh.19970820413Citations: 2AboutPDF ToolsRequest permissionExport citationAdd to favoritesTrack citation ShareShare Give accessShare full text accessShare full-text accessPlease review our Terms and Conditions of Use and check box below to share full-text version of article.I have read and accept the Wiley Online Library Terms and Conditions of UseShareable LinkUse the link below to share a full-text version of this article with your friends and colleagues. Learn more.Copy URL Share a linkShare onFacebookTwitterLinkedInRedditWechat No abstract is available for this article.Citing Literature Volume82, Issue41997Pages 563-563 RelatedInformation

A review of stock-recruitment relationships with reference to flatfish populations

The relationship between stock and recruitment in fish populations has been a subject of many studies and some controversy, even to the extent that it has been questioned whether the two can be related in any meanignful way. The denial of a meaningful stock-recruitment relationship has profound and disturbing influences on the science of fish population dynamics and would seem to be something of a policy of despair. A more constructive approach is to acknowledge the difficulties in establishing a stock-recruitment relationship from the available information but still to seek the best interpretation of the data for the purposes for which the analysis is intended. Among the models that have been developed to fit stock-recruitment curves to data sets are the well-known Beverton-Holt and Ricker curves, both of which have two parameters. Less commonly used is the two-parameter model of Cushing. These two-parameter models have been generalized to give three-parameter models whose shape can be varied by settings of the parameters so as to model a wide range of observed stock-recruitment curves. In this paper these models and their underlying assumptions are described. Statistical methods of fitting the curves to data are reviewed with emphasis on the appraisal of the fitted curve, concentrating on the use for which the fitted curve is intended. Methods of choosing between different curves are discussed. The review is illustrated with examples of stock-recruitment data derived for various flatfish stocks. Among the questions that are discussed is whether there are any features of stock-recruitment relationships for flatfish that differentiate them from those of other species. Methods for testing the null hypotheses that there is no relationship between stock and recruitment and that recruitment in flatfish is not influenced by environmental or other biological factors are described. Of the 20 flatfish stocks for which suitable stock and recruitment data are available, it is shown that in six cases there is a statistically significant relationship between stock size and recruitment. In one of these cases the relationship is significantly strengthened by the incorporation of an environmental measurement. Of the six significant stock-recruitment relationships one is strongly domed and three are the right-hand arm of a domed curve. In the other two cases average recruitment increases with increasing stock size, but it is not possible to differentiate between a domed and an asymptotic curve. This evidence of density-dependence in the stock-recruitment relationships for flatfish is further strengthened by an examination of those cases in which the model of constant recruitment, independent of stock size, is not rejected. In eight of these stocks it is shown that the model of constant recruitment is favoured in preference to a model in which recruitment is directly proportional to stock size. Although recruitment may vary about a constant average level over a restricted range of stock size, it is not biologically possible for a population to sustain a high level of recruitment at low stock sizes. Thus in these eight cases there is further evidence of an underlying, but as yet unidentified, stock-recruitment relationship.

Gravel-Pit Lakes Connected with the River Rhine as a Reserve for High Productivity of Plankton and Young Fish

During the last two decades an increasing number of sand and gravel-pits were established in the original flood plain of the River Rhine. Some of these are connected with the stream by a small canal for the transport of the spoil. Some of these dredged lakes have been studied during recent years at the ecological field station of the University of Köln, with regard to seasonal phytoplankton succession, productivity of copepods and cladocerans, occurrence of macrozoobenthos, and both spawning and recruitment of fish populations. These eutrophic lakes represent a valuable substitute biotope for lost lentic waters of the former flood plain. They offer via the canal connection an advantageous habitat to resident fish species of the Lower Rhine, (1) for reproduction and growth of the 0+-generation, and (2) for shelter during flood events. Recommendations for reclamation plans of such lakes are required.

On Competition and Temporal Variation in Temperate Freshwater Fish Populations

Recruitment in fish populations is characterized by a high temporal variability and a considerable stochasticity. It has therefore been suggested that fish populations should be likely candidates for coexistence based on the storage mechanism. Many characteristics of fish populations such as high variability in year class strength and mortality biased towards smaller (younger) individuals are also elements that make coexistence based on the storage mechanism likely. At the same time, considerable experimental evidence usually associated with deterministic competition models, such as density dependence in individual growth rates, density dependence in populations densities, and competition-related niche dynamics, is also present. We use temporal variation in temperature, an environmental variable involving both a stochastic and a regular (seasonal) component, to illustrate how both coexistence based on a storage mechanism and patterns expected from deterministic competition models may co-occur. Temperature is as important in fish as in other poikilothermic organisms, since the carrying capacity of the population will vary with temperature through the latter's effect on the metabolic requirements of individuals. Seasonal variation in temperature will, through its effect on metabolic demands, also cause favourable periods to alternate with unfavourable periods, i.e. environmental effects covary with competition effects as assumed in lottery models. We suggest that seasonal variation in temperature will promote coexistence and at the same time allow competition to be a regular event with significant evolutionary potential. Experimental and field evidence that supports the idea of a seasonal variation in resourse limitation strongly coupled to temperature is provided.