Juvenile bottlenecks and salinity shape grey mullet assemblages

Juvenile bottlenecks and salinity shape grey mullet assemblages in Mediterranean estuaries Author: Luis Cardona a, *, Bernat Hereu b, Xavier Torras c, 1 Reporter: 曾睦敦

環境中優勢種推論示意圖 L. Aurata L. salinity 五種地中海 河口烏魚 L. Aurata L. salinity M. Cephalus L. ramado C. labrosus >13 環境 鹽度 競爭 能力 弱 : 族群中優勢種 弱 強 L. Aurata <13 強 M. Cephalus L. ramado C. labrosus 競爭 能力 M. Cephalus L. salinity L. ramado C. labrosus 有 L. ramado 外來種 鯉魚 無 C. labrosus

INTRODUCTION 1 2 3

MATERIAL AND METHODS Samples: August and September 1997 at 42 different sites (Aiguamolls del’emporda 12, Ebro Delta 11, Minorca 19) A trammel net 135 -m long and 1. 5 -m deep, with a stretched mesh size of 25 -mm, was laid for 24 h at each site. Observer tool: Practical Salinity Scale

MATERIAL AND METHODS 分成稚魚前期及稚魚後期 (shorter than 17 cm for Liza saliens and shorter than 20 cm for the other four species) This is because early juveniles are typically 1 - or 2 years-old (Brusle, 1981; Cardona, 1999) Connectivity with the sea was also considered and sampling sites were also classified as blind (irregular and unpredictable connexions with the sea), seasonally open (connected with the sea throughout most of the rainy season, i. e. , Octobere. May) and open (connected with the sea year round).

MATERIAL AND METHODS Statistics: (1) Mann-Whitney U Test (2) Two-way ANOVA Programme: SPSS 12

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