Historical evidence of the influence of climate on some commercial fish populations of the Barents and White seas Dmitry Lajus ( State University of St.Petersburg) Julia Lajus, Alexey Kraikovsky, Zoya Dmitrieva, Daniil Alexandrov ( European University at St.Petersburg RUSSIA Influence of Climate Change on North Atlantic Fish Stocks, Bergen, May 2004

HISTORY OF MARINE ANIMAL POPULATIONS (HMAP) (part of Census of Marine Life Project, Sloan Foundation) To use historical data for extracting biologically significant information Use of data for pre-statistical period (before end of 19 th century) for studying dynamics of fish populations: Problems: - little information on circumstances of fishing (for instance, no data about recruitment, little data on fishing effort etc.); - gaps in data series, - often uncertain reliability of data Advantages: - potential for obtaining long-term data series, - in pre-statistical period fish populations were not affected by overfishinig, pollution, habitat degradation etc.

Data source: recent findings from 17 th and 18 th centuries in clostrial and state archives of Moscow, St.Petersburg, Arkhangelsk.

Day of July 1770 Salmon caught Date Number Poods&foonts [weight]

Data source: recent findings from 17 th and 18 th centuries in clostrial and state archives of Moscow, St.Petersburg, Arkhangelsk. Only data sets which allow us to account for fishing effort, i.e. to analyse catch per unit effor (CPUE) have been selected. Two cases: Fisheries of Solovetsky monastery for cod and halibut at Kildin Island, 18 th century. Fisheries for Atlantic salmon in the White and Barents sea basins, th century.

Kildin Island and scheme of main currents and fish migrations in the Barents Sea Kildin Island

Fishing for cod & halibut at Murman coast by hook and line

Сod and halibut сatches (metric tonns/boat per year) at fisheries of Solovetsky monastery, Kildin Island autocorrelations: lag=1, n=22, r=0,52 (p=0,013) lag=2, n=21, r=0,36 (p=0,104)

Atlantic salmon fisheries in the basins of the White and Barents seas, th centuries

Life cycle of Atlantic salmon in the Russian North

Ancient stone drawing of salmon fishery White Sea area, 6-7 thousand years ago

Salmon fishing gear: weir at Onega River, middle of 19 th c

garva Salmon fishing gear ostroga

Studied Atlantic salmon fisheries

0 0,5 1 1,5 2 2, Onega River Vyg River Varzuga RIver Western Murman Catches of Atlantic salmon, number 0,5 1,5 2, Autocorrelations: lag=1, n=29, r=0,31, (p=0,101) lag=2, n=24, r=0,51, (p=0,010)

Significant autocorrelations tell as about non-random changes in catches. What are potential reasons of such changes? Variation in migration patterns, and therefore, in availability for coastal fisheries (cod and halibut) consequence: - negative correlation with temperature without lag-period (?) Variation in recruitment, and therefore, in abundance of adult fish consequences: - positive correlation with temperature with some lag - about ten years for cod and halibut and about five for salmon; - positive correation with abundance of other populations from the north of the distribution range; - negative correlation with populations from south of species’ distribution range

Correlation of obtained data with available relevant literature time-series for th centuries our data literature time-series Sources: Iceland temperatures (Bergtharssen, 1969), Greenland temperatures (Bol’sheianov, 2000), Norwegian herring and cod landings (Qiestad, 1994) Introduction of lags gives similar results Assessments of confidential levels accounted for autocorrelations

Catches and weight of Atlantic salmon in the Varzuga district 2,5-3,0 kg 6,3 kg in average 11,5 kg in average, Indera River, n=33

Location (fishing place) Number of fish caught Weight (poods) as appear in document Average weight (kg) BelkovaiaBol`shaia VelikaiaIzba Indera River PoplavnaiaRendoga KharovnaiaRendoga Kicha (Kitsa) River Chavanga River Strelka (Strel`nia) River Gremiachaia MalaiaOgorodnaia Number and weight of salmon, caught by Solovetsky Monastery at various fishing places in Varzuga district in 1763 ( Reference: RGADA. F Op. 5. D L. 9 back -13 back)

Conclusions Historical data show: - non-random year-to-year variation in catch sizes of cod & halibut and Atlantic salmon; - large variation in average weight of Atlantic salmon in different years. In absence of antropogenic influences these changes must be explained by variation of natural environmental conditions. Likely, catches per unit effort of cod & halibut and Atlantic salmon in th centuries are positively associated with temperature changes