Alternative bait trials in the Barents Sea snow crab fishery.

Tomas Araya-Schmidt,Paul D Winger,Leonore Olsen,Lasse Rindahl,Roger B Larsen

doi:10.7717/peerj.6874

Abstract

Commercial harvesting of snow crab (Chionoecetes opilio) in the Barents Sea started in 2012 by Norwegian fishing vessels. This new fishery has significant bait requirements, representing an emerging conservation challenge. In this study, we evaluate the performance of five alternative (natural) baits manufactured from the waste stream of existing and sustainably managed harp seal (Pagophilus groenlandicus) and minke whale (Balaenoptera acutorostrata) capture. Five different types of new bait were evaluated, including seal fat (SF), seal fat with skin (SFS), seal meat with bone (SMB), whale fat with skin (WFS), and whale meat with fat (WMF). A comparative fishing experiment was conducted onboard a commercial snow crab fishing vessel in the Barents Sea (May–June, 2016) to evaluate the performance of traditional bait (squid, Illexs spp.) and alternative baits at catching snow crabs. Performance of the different baits were compared on the basis of the number of commercial crab caught per trap haul catch per unit effort (CPUE) and carapace width (CW). Our results showed that SF and SFS performed equally well to traditional bait, with no statistical difference in CPUE (p-value = 0.325 and 0.069, respectively). All of the other experimental baits significantly decreased CPUE, when compared to squid. No significant effect of bait treatment on CW was detected and the cumulative distribution of CW was the same between control traps and each of the bait treatments. Overall the results indicated that SF and SFS represent a viable alternative to replace traditional bait, addressing a key conservation challenge in this bait intensive snow crab fishery.

Highlights

Snow crab (Chionoecetes opilio) is considered an invasive species in the Barents Sea
Control traps produced a median of 8.0 crabs per trap haul (Fig. 4); traps baited with seal meat with bone (SMB) captured 79.3% fewer crabs, WFS captured 75.8% fewer crabs, and WMF 57.7% fewer crabs, according to model estimates (Table 3; Fig. 4)
Results from south location indicated that seal fat (SF) (D 1⁄4 0.109, p-value 1⁄4 0.693), seal fat with skin (SFS) (D 1⁄4 0.0740, p-value 1⁄4 0.662), and SMB (D 1⁄4 0.270, p-value 1⁄4 0.354) traps had the same cumulative distribution of carapace width (CW) when compared to control traps (Fig. 7)

Summary

Introduction

Snow crab (Chionoecetes opilio) is considered an invasive species in the Barents Sea. Since the first findings in the southeastern part of the Barents Sea (Kuzmin, Akhtarin & Menis, 1988), the abundance and distribution of snow crab has increased steadily every year (Alvsvåg, Agnalt & Jørstad, 2009; Pavlov & Sundet, 2011). Snow crab colonized favorable conditions in the Barents Sea, including depths, substrates, and temperature ranges. Alternative bait trials in the Barents Sea snow crab fishery. It is currently distributed in areas with bottom temperatures ranging from -0.7 to 3.4 C and at depths between 180 and 350 m (Alvsvåg, Agnalt & Jørstad, 2009). Its preferred habitat is currently found in the northern parts of the Russian Exclusive Economic Zone and in international waters of the Barents Sea, covering an overall area more than 34% of the Barents Sea (Kaiser, Kourantidou & Fernandez, 2018)

Methods

Results

Discussion

Conclusion