Saturday, 10 October 2009

Identifying fish larvae and juveniles

The management of exploited Western Indian Ocean (WIO) fisheries and reefs is dependent on the reliable identification of juvenile fishes, both to understand their potential dispersal, recruitment and recovery, but also to help understand their importance as a food source to many higher order predators (through gut content analysis).
Typically, juvenile/larval identification is difficult as regional keys and guides are scarce the world over and juveniles and adults often show little resemblance to each other. The ultimate aim of this project is, therefore, to develop an illustrated identification key/database of common juvenile and larval fishes, to facilitate their reliable routine identification in the field.
The Fish Barcode of Life initiative (FISH-BOL) aims to facilitate reliable fish species diagnostics using mitochondrial DNA cytochrome oxidase I (COI) sequences that are kept on a centralised database. By comparing COI sequences from juveniles to those already available from adults, species can be matched and identified. The correctly identified juveniles may then be described and illustrated in a field guide.
The current sampling strategy provides for 10 to 16 surface trawls during this cruise, in coastal and off-shore areas close to the Comoros, Mayotte, Madagascar, Mozambique and Tanzania. To date, two surface trawls have been completed and have yielded some 42 species of juvenile/larval fishes. Once back in the laboratory, barcoding will identify these by linking their DNA sequences to those of existing sequences from a database of adult fishes.
The current study is a part of a regional (WIO) research effort that has previously been collecting samples from throughout the Mozambique Channel. Examples of identified juveniles and their corresponding adult stages are shown in the figure below.


Authors: S. Kaehler & M. Mwale












Comments: Post a Comment





<< Home

This page is powered by Blogger. Isn't yours?

Subscribe to Posts [Atom]