Blue Shark (Prionace glauca) Distribution in the Pacific Ocean: A Look at Continuity and Size Differences

Abstract

Blue shark (Prionace glauca) is a major bycatch species in the long-line and gill-net Pacific Ocean tuna fisheries, and the population structure is critical for fishery management. We employed generalized additive models to analyze the fork lengths of blue sharks and biological data (i.e., feeding level, sex, and genetic data), as well as environmental and spatial variables (i.e., sea surface temperature, month, longitude, and latitude) collected from 2011 to 2014 by the Chinese Thunnus alalunga long-line tuna fishery observer program. Fork length was significantly affected (p < 0.05) with location (latitude and longitude) and sex, and positively effected with sea surface temperature. No relationships were found between fork length and feeding level, month, and genetic data. We detected fork length differences among blue sharks over the range of the observed data, but the genetic data implied a panmictic population. Thus, we hypothesize that the genetic similarity was so close that it could not be well separated. Based on the precautionary principle, we recommend that the blue shark in the Pacific Ocean should be managed as two independent populations to ensure its sustainable use.

Isolation and Biochemical Properties of Type II Collagen from Blue Shark (Prionace glauca) Cartilage

“…Blue shark (Prionace glauca) belongs to Eukarya, Animalia, Chordata, Chondrichthyes, Carcharhiniform, Carcharhinidae and Prionace. It is widely distributed in the coastal and oceanic regions of temperate and tropical waters [27]. Blue sharks are the main bycatch target in longline fisheries and gillnet fisheries [27,28].…”

“…It is widely distributed in the coastal and oceanic regions of temperate and tropical waters [27]. Blue sharks are the main bycatch target in longline fisheries and gillnet fisheries [27,28]. Surveys show that in many countries or regions, blue shark account for an average of a third or even more than half of the total catch in their large pelagic fisheries [29][30][31][32][33].…”

“…Surveys show that in many countries or regions, blue shark account for an average of a third or even more than half of the total catch in their large pelagic fisheries [29][30][31][32][33]. The fins of the blue shark are the traditional seafood, and its meat can be made into fish balls [27,32]. By-products from shark processing, particularly skin (10%), fin (1-3%) and cartilage (6-7%), can be used as potential source material for collagen extraction [34][35][36].…”