The Korean flagged bottom longliners, “Jung Woo No. 2” and “Jung Woo No. 3”, have participated in the exploratory fishery from 1st Dec 2010 to 10th Jan 2011 for Dissostichus spp. The fisheries took place in subarea 88.1 BCJL. During their activities, the vessels gathered scientific information on Dissostichus spp. and by-catch such as their distribution, size, sex, weight, etc. This paper presented the results from the fisheries and comparison of statistics in each SSRU.
Total catch including by-catches in 88.1 BCJL were 35,436 fishes. Dissostichus Spp. was the highest catch, contributing 99.62% to the total catches in 78 hauls while by-catches were 133 fish. The CPUEs of Dissostichus Spp. in 88.1 J and L appeared dramatic higher rate than the CPUEs in 88.1 B and C. Mean CPUE (number / km) of Dissostichus Spp. for total of 78 sets, for instance, was 16.67911. This figure was higher than the figure of 5.676294 in 88.1 B and the figure of 2.719449 in 88.1 C. On the other hand, CPUE (number / km) in both 88.1 J and L were over 19. The highest CPUEs in each SSRU were the CPUE at a depth of 1,500 to 1,600M in 88.1B and C, a depth of 600 to 700 in 88.1J and L.
The composition of the by-catch species was WGR, ANT, GRV, PGR, and NOS in subarea 88.1. WGR was the highest catch among the by-catches. WGR, ANT were found in 88.1 BC and GRV was found in 88.1 B only. In 88.1 J, PGR and NOS were caught without any WGR, ANT and GRV.
The ratio of males to females in subarea 88.1 BC was 1:0.63 (males: 363, females: 228 fishes) and it was 1:1.20 (males: 579, females: 696 fishes) in subarea 88.1 JL. The ratio of males to females in 88.1 BC is higher than the ratio in 88.1 JL. Number of males was dominated in all range of depth from 1,400 m to 2,000 m of 88.1 BC. On the other hand, females were predominant in subarea 88.1 JL. Although females were mostly predominant in 88.1 JL, at depth from 600 m to 700m in 88.1L number of males was more than that of females(male 16 : female 14).
Size of sampled fish over 120 cm was highly concentrated in 88.1 BC. On the other hand, size of sampled fish up to 120 cm was densely populated in 88.1 JL. Size of Dissostichus Spp. caught in 88.1 B was most widely distributed compared to 88.1 C, J and L. It ranged from 59 cm to 187 cm. On the other hand, Size of Dissostichus Spp. in 88.1 C was concentrated in 138 cm to 174 cm.
On the basis of spreadsheet for calculating the tag overlap statistic supported by CCAMLR Secretary (COMM CIRC 10/123SC CIRC 10/69), “Jung Woo No. 2” and “Jung Woo No. 3” have achieved 92% and 87% of tag overlap in the 2010-2011 season. In addition, tagging rates of both vessels were 1.09 and 1.04.
Abstract:
Although Spanish longline has been used in CCAMLR fisheries for a number of years, detailed information on the fishing gear and the procedures for setting/hauling has not been described in detail and is not currently included the CCAMLR gear library. In order to contribute to the assessment of potential adverse impact on VMEs and on incidental mortality of seabirds by Spanish longlines, this paper presents a gear configuration and procedures of setting/hauling for Spanish longline based on that used by the Korean flagged vessels.
Abstract:
The depletion-corrected average catch (DCAC) formula is an extension of the potential-yield formula, and it provides useful estimates of sustainable yield for data-poor fisheries on long-lived species. Over an extended period (e.g. a decade or more), the catch is divided into a sustainable yield component and an unsustainable “windfall” component associated with a one-time reduction in stock biomass. The size of the windfall is expressed as being equivalent to a number of years of sustainable production, in the form of a “windfall ratio”. The DCAC is calculated as the sum of catches divided by the sum of the number of years in the catch series and this windfall ratio. Input information includes the sum of catches and associated number of years, the relative reduction in biomass during that period, the natural mortality rate (M, which should be ,0.2 year21), and the assumed ratio of FMSY to M. These input values are expected to be approximate, and based on the estimates of their imprecision, the uncertainty can be integrated by Monte Carlo exploration of DCAC values.
