KacmhatNIRO specialists published their overview on recent pollock fishery in the Sea of Okhotsk. According to them, fishing season of 2016 proved that the Sea of Okhotsk pollock stocks are in good condition.
During January 1 till March 31 2016, the most extensive fishery in Russia took place in the northern part of the Sea of Okhotsk within Northern Sea of Okhotsk subzone (61.05.1), West-Kamchatka subzone (61.05.2) and Kamchatka-Kuril subzone (61.05.4). This year fishing season ended 9 days earlier than usual.
Specialists from the Far East fishery research institutes, in particular, from KamchatNIRO, traditionally participated in fishery activities monitoring. From the beginning of fishing season scientific observers worked on commercial trawlers harvesting pollock. By joint efforts of all Far East institutes, comprehensive data and information were collected in all areas of Pollock distribution. Great massive of fishery and bio-statistical information is to be processed and carefully analyzed, however, some results of the completed fishing season can be summarized now.
Meteorological conditions existing in the Sea of Okhotsk during entire winter season of 2015-2016 were largely contributing to intensive water cooling in the surface layer. The ice cover square area in the Sea of Okhotsk was remaining within its normal limits during the greater portion of the winter and noticeably exceeded these limits only at the end of the reporting period. In late February – early March, ice cover data for the eastern part of the sea were higher than their multi-year mean by 14-15% which can certainly be considered as one of adverse factors affecting this year’s fishing conditions. The winter season of 2015-2016 in North Sea of Okhotsk can be classified as “cold” in sea surface temperature terms.
According to the scientific data, the Sea of Okhotsk is populated by a single pollock stock within the North Sea of Okhotsk (61.05.1), West Kamchatka (61.05.2), Kamchatka–Kuril (61.05.4) subzones which has a complicated intra-population structure.
In 2016 TAC in 61.05.1 subzone has been set at 348.0 thsd tons, 61.05.2 – 348.0 thsd tons, 61.05.4 – 270.7 thsd tons, which in total exceeded level of 2015 by 62.7 thsd tons. Same as in 2010-2015, quotas in subzones 61.05.2 and 61.05.4 were based in 2016 on the total TAC of 618.7 thsd tons allocated for both subzones collectively.
Total pollock catch by mid-water trawls in a commercial fishery mode in the Russian EEZ (target fishery) amounted to approx. 766.8 thsd tons by the end of March 2016 which is larger than a year before (717.9 thsd tons). 36.1 thsd tons of pollock were taken by other fisheries (38.4 thsd tons in 2015), mostly on the Danish seine fishery off West Kamchatka. Total pollock catch in the season A amounted to 802.7 thsd tons; and TAC was taken by 83.1%.
One of reasons why catch in the season A in 2016 surpassed catch in the similar period of 2015 by 48.9 thsd tons is, first of all, a larger number of catchers and, accordingly, larger number of fishing operations (7945 and 7043 ship-days respectively) despite the fact that average catch per unit effort for trawlers was lower than in the last year (96.5 and 101.9 tons/ship-day respectively).
Daily pollock catch in the the Sea of Okotsk during the 2016 fishing season was gradually rising from 1,426 thsd tons in early January to 10,444 thsd tons in late January as the number of catchers and of their efforts was increasing. After that, daily catch varied in the range of 7,937 to 13,102 thsd tons till the last 5-day period of March averaging at 10,039 thsd tons. Maximum catch was registered on the last day of the fishing run period and amounted to 16,899 thsd tons. Such picture is quite typical of the pollock fishery in the Sea of Okhotsk and is explained by the fact that, firstly, in March pollock forms its densest aggregations of spawners migrating to future spawning areas and, secondly, fishing is most favorable in this period due to high roe output.
Fleet allocation in fishing season 2016 was different from the 2015 season as well as from multi-years average. Traditionally fishery started in area of the Lebed Bank and in area of the Ozernovsky seabed drop-off. As for West Kamchatka subzone, fishing in January was rather successful in some years in area of the Lebed Trough and in February–March – north of 58 00 N and in the mouth of the Shelikhov Bay. Fishing conditions in North Sea of Okhotsk subzone in January–February are normally worse than in other areas. In some years, fishing was rather successful on the Lebed Rise, Pritauisky area and Kashevarov Bank but the focus was traditionally placed on March–April.
Same as in 2015, pollock fisheries were concentrated in January 2016 in the North Sea of Okhotsk subzone. Total monthly catch in this area was about 125.2 thsd tons which is more than the last year’s record high of 114.9 thsd tons. On some days, the number of vessels in this area reached 59 and maximum daily catch amounted to 4.0 thsd tons.
As ice conditions critically aggravated in February, the focus of fishing activities gradually shifted to Kamchatka-Kuril subzone while in the last year, when ice conditions was considerably less severe than in this year, it shifted to West Kamchatka subzone. Up to 76 vessels of different tonnage were operating during that month in subzone 61.05.4, with maximum and mean daily catch being 6.0 and 4.8 thsd tons respectively. Total catch in this subzone in February was some 140.0 thsd tons. The North Sea of Okhotsk and West Kamchatka subzones ranked second and third with total catches of 89.2 and 44.1 thsd tons respectively.
When ice conditions improved in March 2016, pollock fishing areas somewhat expanded compared with February but Kamchatka-Kuril subzone remained the main fishing area. Total monthly catch in this area was approx. 186.6 thsd tons of pollock, with a maximum number of vessels at any one time being 91 and maximum and mean daily catch being 10.4 and 6.2 thsd tons. Catch intensity was much lower in subzones 61.05.1 and 61.05.2 where 77.2 and 72.0 thsd tons was caught respectively.
By data of scientific observers collected directly onboard of commercial fleet in the Northern Sea of Okhotsk subzone in January 2016 at the mid-water trawl pollock fishery catches varied from 10,0 to 15,0 t/hour with an average at 13,3 tons per hour of trawling. Fish size was in the range of 20 to 59 cm, with the size group of 42-45 cm dominating (53.2%) and average size being 42.4 cm. An average percentage of juvinile fish was 5.1% and its average weight was 0.588 kg. Pre-spawning individuals were absolutely dominating among spawners.
In February, pollock catches per effort in 61.05.1 subzone increased varying between 11,9 and 43,3 t/hour of trawling with 27,9 t/h in average. Fish size was completely the same as in previous month. Share of fish less then 37 cm in lenth was 5,0%, average mass – 0,585 kg. In comparison to January, in February spawning and post-spawning individuals were registered in few numbers.
In Kamchatka-Kuril subzone in February catches varied from 4,3 to 23,2 t'hour with average at 14,3 t/hour. Fish size was from 29 to 61 cm, with the size group of 38-40 cm dominating (38.1%) and mean size being 41.2 cm. In comparison with the North Sea of Okhotsk subzone, catches in this area contained more individuals 35-38 cm long belonging to the strong year-class of 2011. The percentage of undersized fish exceeded 20% in some hauls and averaged at 6.1%, with mean weight being 0.514 kg. Same as in the North Sea of Okhotsk subzone, pre-spawning individuals were dominating among spawners in February, although occasional.
Pollock size distribution in commercial catches did not undergo any considerable change in March – from 7,5 up to 28,0 tons/hour with 14,0 t/h at average. The percentage of fish under 37 cm averaged at 7.4% and its mean weight was 0.519 kg. In comparison with February, the relative number of pre-spawning individuals reduced in March and that of spawning and post-spawning individuals increased.
According to data obtained by an observer from KamchatNIRO, pollock catches on Danish seine fishery reached 27 tons per operation, but in average was about 5,4 tons per effort. Size distribution of pollock essentially differed from trawl catches. Fish length varied from 34 to 74 cm, with individuals 44-46 cm long dominating and mean size being 47.1 cm. The percentage of individuals under 37 cm was 0.3% and their mean weight was 0.752 kg. The bulk of spawners were at various stages of pre-spawning maturity, about 5.5% of males and 10.8% of females were in spawning condition and 0.1% of females were in post-spawning condition.
KamchatNIRO scientists concluded that that season A of the 2016 Sea of Okhotsk Pollock fishery in general confirmed scientists’ opinion that Sea of Okhotsk Pollock stock is in good condition. It is clearly supported with strong fishery results.
Original publication in Russian is available at the KamchatNIRO website: http://www.kamniro.ru/obzory_promysla/promysel/itogi_ohotomorskoj_mintaevoj_putiny_2016_goda_vzglyad_specialistov_kamchatniro
Full publication translated into English in available at the Publications page.