Influence of Seascape on Coastal Lagoon Fisheries: the Role of Habitat Mosaic in the Venice Lagoon

Luca Scapin,Fabio Pranovi,Piero Franzoi,Matteo Zucchetta

doi:10.1007/s12237-021-00986-3

Abstract

Fisheries are a staple human activity supported by coastal lagoons. Together with water quality and trophic status, lagoon morphology is acknowledged as one of the main ecological drivers of fishery yields; however, the role of lagoon seascape structure is still poorly understood. This paper investigates how morphological variables, habitat distribution and seascape diversity and complexity affect yields of artisanal fishery performed with fyke nets in the Venice Lagoon (northern Adriatic Sea, Italy). Two spatial scales were considered in the analysis, with water quality parameters (temperature, salinity, dissolved oxygen, turbidity, water residence times, N, P and chlorophyll-a concentrations) being measured at a fine, fyke-net scale and morphological (average bottom elevation and sediment grain size) and habitat features (habitat proportion, diversity and complexity) being measured at a broader, seascape scale. Generalised linear mixed models were employed to model 8 years of nekton and green crab catches, disentangling the role of broad-scale morphology and seascape from that of fine-scale water quality. Broad-scale variables clearly influenced fishery target species. Among them, lagoon residents were associated with specific morphological and habitat characteristics, while marine migrants showed a stronger link with overall habitat diversity and complexity. This evidence emphasises how artisanal fishery in the Venice Lagoon relies on the conservation of morphological and habitat heterogeneity. Moreover, it highlights how habitat restoration performed at the seascape level should also be taken into account, in addition to controlling hydrology and water quality, when managing fishery resources in coastal lagoons.

Highlights

Transitional waters are highly productive ecosystems that support a variety of fishery activities, most of which are practised at small-scale (Granzotto et al 2001; Crespi 2002; Gomez et al 2006; Pérez-Ruzafa and Marcos 2012)
The regulating and supporting role of morphological heterogeneity in the Venice Lagoon has motivated the inclusion of habitat restoration practices among the management options for the lagoon basin in more recent years (Curiel et al 2005; Facca et al 2014; Feola et al 2018; Scapin et al 2019b, c), integrating the traditional approaches based on water quality and hydraulic management (Pérez-Ruzafa et al 2011; Cataudella et al 2015)
For the purposes of this study, following the approach of Zucchetta et al (2016) six broad macroareas were identified in the lagoon based on degree of confinement (Cucco et al 2009), salinity, sediment characteristics and overall seascape features: Chioggia (CH), Ca’ Zane (CZ), Lago dei Teneri (LT), Ponte della Libertà (PL), Poveglia (PO) and San Giuliano (SG) (Fig. 1a)

Summary

Introduction

Transitional waters (estuaries and coastal lagoons) are highly productive ecosystems that support a variety of fishery activities, most of which are practised at small-scale (Granzotto et al 2001; Crespi 2002; Gomez et al 2006; Pérez-Ruzafa and Marcos 2012). The regulating and supporting role of morphological heterogeneity in the Venice Lagoon has motivated the inclusion of habitat restoration practices among the management options for the lagoon basin in more recent years (Curiel et al 2005; Facca et al 2014; Feola et al 2018; Scapin et al 2019b, c), integrating the traditional approaches based on water quality and hydraulic management (Pérez-Ruzafa et al 2011; Cataudella et al 2015). Water temperature is known to affect both reproductive investment and fishery catches of grass goby (Zosterisessor ophiocephalus) (Zucchetta et al 2012; Pranovi et al 2013), one of the primary fishery resources in the Venice Lagoon (Provincia di Venezia 2009; Provincia di Venezia 2015)

Methods

Results

Conclusion