Morphometric Relationships of the Global Invader Callinectes sapidus Rathbun, 1896 (Decapoda, Brachyura, Portunidae) from Papapouli Lagoon, NW Aegean Sea, Greece. with Notes on Its Ecological Preferences

Thodoros E Kampouris,Ioannis E Batjakas,Emmanouil Kouroupakis

doi:10.3390/fishes5010005

Abstract

Callinectes sapidus is native to the Atlantic coasts of the Americas. In the Mediterranean, it appeared around 1949 and though that it is established in East Mediterranean waters, relevant studies are limited. The aim of the present study is to report quantitative and qualitative data on the blue crab’s biology and ecology in its non-native range, that are indispensable for management purposes. Papapouli Lagoon is in Thermaikos Gulf and is ecologically impacted by the blue crabs. Fyke nets with a 20 mm mesh opening were soaked for 12 to 14 h during each survey. Abiotic environmental parameters were obtained. The length–weight relationships were expressed by the equation W = aLb. The species’ ecological preferences at Papapouli Lagoon were assessed with PERMANOVA analysis, using the abiotic parameters as factors. Student’s t-tests were used to assess the differences between sexes. The sex ratio of the blue crab’s population was assessed by a Chi-square (χ2) analysis. The sex ratio was found to be 1.28:1, in favour of males. The most dominant group size of male blue crabs was the 61–70 mm of CL and 130–139 mm of CW. Also, the dominant size group of female blue crabs was 60–69 mm of CL and 120–129 mm CW. The maximum abundance of blue crabs was recorded at a salinity range from 24‰ to 25‰ and the water temperature range was from 26 to 28 °C.

Highlights

The blue crab Callinectes sapidus Rathbun, 1896, is distributed from Nova Scotia to Argentina including the Gulf of Mexico and the Caribbean Sea
The sampling size is sufficient, and the observed differences were expected, since male blue crabs are generally larger in size [14]
Female blue crabs demonstrated negative allometry that is in accordance with earlier studies from Turkey and Egypt [10,37]

Summary

Introduction

The blue crab Callinectes sapidus Rathbun, 1896, is distributed from Nova Scotia to Argentina including the Gulf of Mexico and the Caribbean Sea. In the Mediterranean Sea, the species is exploited in Turkey [8] and, to a lesser extent, in Italy [9], Egypt [10] and Greece [11,12,13,14]. In the Mediterranean Sea, the blue crab appeared around 1949 [12,23] and is widely distributed along the coasts. Morphometrics and length–weight relationships are often used to study population characteristics and at stock assessment of commercially important species, for example, in [28,29]. The aim of the present study is to report quantitative data regarding the species’ allometric growth and qualitative data on the blue crab’s biology ecological preferences in its non-native range in the Eastern Mediterranean and Northwest Aegean Sea for the first time. Studies like the present are quite useful for scientists but for policymakers and at non-indigenous and invasive species management plans

Results

Discussion

Study Area and Sampling Methodology

Morphometric Measurements

Statistical Analyses