The effect of a minimum length specification on visual estimates of density and biomass of coral reef fishes

Autor:	Angel C. Alcala, D. R. Bellwood
Rok vydání:	1988
Předmět:	Biomass (ecology) geography Oceanography geography.geographical_feature_category Coral reef fish Abundance (ecology) Size frequency Statistics Fish Environmental science Coral reef Aquatic Science
Zdroj:	Coral Reefs. 7:23-27
ISSN:	1432-0975 0722-4028
DOI:	10.1007/bf00301978
Popis:	The effects of fish length on visual estimates of fish abundance and biomass are assessed based on analyses of size frequency distributions. A 2 cm change in the specified minimum size of fish surveyed produced a calculated change of 14.5 to 126% in numerical estimates. A change of 28.4 to 411% was calculated for a 4 cm change. The extent of the change in the numerical estimate varies with the family considered but, in all cases, was most marked if the specified minimum size was decreased. The effects upon biomass estimates are less marked. In the Scaridae, for example, there is a calculated change of 4.1 to 7.4% for a 2 cm change in the minimum specified size. The changes in the estimates are discussed in relation to the use of visual survey techniques for assessing reef fish standing stocks.
Databáze:	OpenAIRE
Externí odkaz:	https://explore.openaire.eu/search/publication?articleId=doi_________::45688455b90364093f76c7c2ff6f346c https://doi.org/10.1007/bf00301978 Zobrazit plný text záznamu Full text from SpringerLink