Thumbnail Image

Long and short-term trends of Mediterranean fishery resources

Year of publication 1997

Place of publication Rome, Italy ;

Pages 72

Author L. Fiorentini and J.F. Caddy and J.I. de Leiva

Product type Book (series)

ISBN 9251040257

Series title General Fisheries Commission for the Mediterranean (GFCM) - Session Reports

Series number 1020-9549 - 69

Edition 1

Synopsis (short abstract) This study makes use of the recently published (FAO 1995) 45 year time series (1950-1994) of landings now available from FAO through the program FISHSTAT-PC (Version 5094/96 of March 1996) to analyse long-term trends and separate them automatically in a number of categories using an expert system for data analysis. Landing time series of the most important commercial species and group of species of both West (148 species) and East (137 species) Mediterranean have been processed with this program written in Pascal, in order to analyse and categorize long and short-term trends in these fisheries. Species trends have been categorized following a description of the different stages a fishery could pass through in time (new, rising, stable, declining, recovering and collapsed fisheries). Species have been also arranged into ecological or biological categories (estuarine, benthic and coastal, pelagic, large pelagic, demersal and slope resources), and differences between West and East Mediter ranean trends were sought for the same and different species. A ranking of the most important commercial species using 1992 catches, as well as by 1992 total value of landings, have been carried out, and a comparison between West and East Mediterranean fisheries has been provided.

Statutory body / Meeting title General Fisheries Commission for the Mediterranean (GFCM)

Cite this content as:

Fiorentini, L.; Caddy, J.F.; de Leiva, J.I. Long and short-term trends of Mediterranean fishery resources. Studies and Reviews. General Fisheries Council for the Mediterranean. No. 69. Rome, FAO. 1997. 72p.

Language English

Also available in:
No results found.

Related items

Showing items related by metadata.

  • No Thumbnail Available
  • No Thumbnail Available
    Book (series)
    Chronicles of Marine Fishery Landings (1950-1994): Trend Analysis and Fisheries Potential 1996
    Also available in:
    No results found.
    World fishery landing statistics as disseminated by FAO have been completely revised for the period 1950-1969 and time series in the database have been extended backwards by 20 years so that the period covered is now 1950-1994. Through a preliminary analysis of trends, globally and by oceans, we attempt to demonstrate that these extended time series can be very useful in interpreting developments in the world’s fisheries and so help in assessing the present situation as well as for planning and policy-making for the future. Grouping the 200 most important resources into a few categories according to the shapes of their landings trends reveals a variety of patterns which seem to form different segments of a generalised fishery development model comprising undeveloped, developing, mature and senescent phases. The analysis demonstrates strikingly the succession of the passage of the majority of the world’s major resources through these phases, indicating the current general saturation of fisheries development and increasing overexploitation. Fisheries potential was estimated by predicting at which point the relative rate of increase of landings is zero, using the same generalised fishery development model applied to total fishery production data for marine fish and shellfish. The analysis was applied using data aggregated to three different levels, namely (1) a total for all oceans, (2) totals for each ocean, and (3) individual FAO major fishing areas. Estimated fishery potent ial for the world’s oceans increases as the level of aggregation of the data decreases, and the results indicate that marine fishery potential may be higher than has been assumed up to now. The areas and resources which might provide potential increases in production are identified.
  • Thumbnail Image
    Book (series)
    Atlas of the maturity stages of Mediterranean fishery resources 2019
    Also available in:
    No results found.
    This atlas stems from an experience on fish maturity staging carried out at the Mediterranean level. It aims to present sound approaches to maturity sampling for a wide range of Mediterranean species, based on an accurate and precise determination of the different maturity stages. It includes macroscopic photos of gonads belonging to the main species, and for some of them, a validation-based histological analysis is also presented. The main categories investigated in the atlas are bony fish, cartilaginous fish, both oviparous and viviparous, crustaceans and cephalopods. Maturity is one of the most relevant biological parameters used in stock assessment programmes. Indeed, the macroscopic stage of gonadal development is an essential feature in estimating the maturity ogive and spawning stock biomass. It is also useful for determining the spawning season of a species and for monitoring long-term changes in the spawning cycle, as well as for many other research needs related to the biology of fish. In current data collection programmes carried out in the Mediterranean which cover extensive samplings of maturity stages, some specific technical aspects have not always been taken into consideration, and collected data cannot reach the required precision levels. Also, the coding schemes in use and the uncertainty in the interpretation of particular stages can give rise to misinterpretations of the actual maturity stage leading to inaccurate spawning stock biomass estimations. Several stock assessments are therefore based on time-invariant maturity ogives and only partially cover the spatial distribution of the stocks. Hence, on several occasions, the need has been expressed to improve the identification of the macroscopic maturity stages through a standardization of operational procedures and terminology. Hence, one of the solutions for overcoming these problems was to develop an atlas of the macroscopic and histological maturity stages of the main species of commercial interest in the Mediterranean.
Show more

Users also downloaded

Showing related downloaded files

No results found.