Estimating population size of the cave shrimp Troglocaris anophthalmus (Crustacea, Decapoda, Caridea) using mark–release–recapture data

J Jugovic,M Luznik,E V Buzan,E Praprotnik

doi:10.32800/abc.2015.38.0077

Abstract

Population size estimates are lacking for many small cave–dwelling aquatic invertebrates that are vulnerable to groundwater contamination from anthropogenic activities. Here we estimated the population size of freshwater shrimp Troglocaris anophthalmus sontica (Crustacea, Decapoda, Caridea) based on mark–release–recapture techniques. The subspecies was investigated in Vipavska jama (Vipava cave), Slovenia, with estimates of sex ratio and age distribution. A high abundance of shrimps was found even after considering the lower limit of the confidence intervals. However, we found no evidence of differences in shrimp abundances between summer and winter. The population was dominated by females. Ease of capture and abundant population numbers indicate that these cave shrimps may be useful as a bioindicator in cave ecosystems.

Highlights

IntroductionThe freshwater shrimp genus Troglocaris (Dormitzer, 1853) consists of four subgenera distributed in the Western Balkans (fig. 1A; Sket & Zakšek, 2009; Matjašič, 1956; Babić, 1922; Jugovic et al, 2011) and the Caucasus (Sadovsky, 1930; Sket & Zakšek, 2009; Marin & Sokolova, 2014) and inhabits underground karst waters flowing to the surface.Not much is known about the biology, ecology, distribution or habitat requirements of the European cave shrimp (Gottstein Matočec, 2003; Juberthie–Jupeau, 1974, 1975; Jugovic et al, 2010a)
The freshwater shrimp genus Troglocaris (Dormitzer, 1853) consists of four subgenera distributed in the Western Balkans and the Caucasus (Sadovsky, 1930; Sket & Zakšek, 2009; Marin & Sokolova, 2014) and inhabits underground karst waters flowing to the surface
81 animals were marked during the three winter sampling occasions

Summary

Introduction

The freshwater shrimp genus Troglocaris (Dormitzer, 1853) consists of four subgenera distributed in the Western Balkans (fig. 1A; Sket & Zakšek, 2009; Matjašič, 1956; Babić, 1922; Jugovic et al, 2011) and the Caucasus (Sadovsky, 1930; Sket & Zakšek, 2009; Marin & Sokolova, 2014) and inhabits underground karst waters flowing to the surface.Not much is known about the biology, ecology, distribution or habitat requirements of the European cave shrimp (Gottstein Matočec, 2003; Juberthie–Jupeau, 1974, 1975; Jugovic et al, 2010a). In this study we aimed to estimate population size for a population of Troglocaris anophthalmus sontica Jugovic et al, 2012, a subspecies of a type species of the genus. This subspecies is currently recorded from four subterranean localities (two in Slovenia and two in Italy) belonging to the Vipava–Soča River System (Jugovic et al, 2012). This river system is located on the north westernmost border of the distribution of subgenus Troglocaris s. The landscape behind the spring is an area of fractured and dissolved carbonate bedrock that stores significant quantities of groundwater

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