Náttúrufræðingurinn

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Náttúrufræðingurinn - 2023, Qupperneq 47

Náttúrufræðingurinn - 2023, Qupperneq 47
það greindist ein til viðbótar.31 Er það sami fjöldi og er í gagnagrunninum sem hér hefur verið notaður. Ef fjöldi skráninga heldur áfram með sömu tíðni það sem eftir er 21. öld verður fjöldi steypireyða sem finnast dauðar talsvert fleiri en á 20. öld. Er það í takt við fjölgun í stofninum eins og talningar sýna. Nú á tímum finnast steypireyðar allt í kringum land en tegundin hefur verið algengust undan Vesturlandi.71,80 Eftir 2001 breyttist útbreiðslan nokkuð og fleiri dýr fóru að halda til undan Norð- austurlandi.74 Rekhvalir, íshvalir og fleiri dauðar steypireyðar hafa fundist mest frá Vestfjörðum til Austfjarða, en einnig nokkuð við Suðvesturland. Íshvalir hafa einungis fundist við norðanvert landið, frá Ísafjarðardjúpi austur í Loðmundar- fjörð eða þar sem ís hefur helst orðið landfastur við strendur landsins. Þættir sem hafa valdið dauða steypi- reyða hafa breyst frá því á 19. öld sem og ástæður fyrir hvalaströndum. Nú hafa engar veiðar verið stundaðar á steypireyðum í rúm 60 ár og hvalveiði- menn missa ekki lengur særðar steypireyðar frá sér. Steypireyðastofn- inn dróst mikið saman eftir að hvalveiðar byrjuðu fyrir alvöru og virðist ekki hafa náð fyrri hæðum og hvalaströnd færri á 20. og 21. öld. Á tímum heimstyrjaldar- innar síðari kom fyrir að steypireyðar festust í kafbátagirðingum en vænt- anlega ekki lengur. Á hinn bóginn má ætla að stórvirkari veiðarfæri og auk- inn veiðifloti hafi skapað aukna hættu fyrir hvali miðað við fyrrum. Þannig að þótt veiðar á steypireyðum séu löngu aflagðar, hafa nýjar ógnir komið í stað- inn sem geta hægt á áhrifum friðunar. ENGLISH SUMMARY The whales at Ánastaðir in 1882, other strandings and ice-locked Blue Whales in Iceland The present paper deals with four main issues, three concerning Blue Whales and one on recent methodologies for species identification of marine mammals: (1) Species determination of the whales which became ice-locked at farm Ánastaðir (N-Iceland) in 1882. Samples were taken from their bones (Fig. 2) and identified using mass spectr- ometry. All turned out to be from Blue Whales (Balaenoptera musculus) (Fig. 1). Further sampling is needed to ascer- tain whether other whale species were also part of the group of 32 that were ice-locked and killed. (2) Records of Blue Whales (in most cases as identified by finders) were ex- tracted from a database of 2082 records (per February 2023) of whale strand- ings and other whales found dead in Iceland (direct hunting excluded). Most of these records included stranded ani- mals, but other mortality factors were also involved, such as ice-locked ani- mals, whales caught in fishing gear, and animals found harpooned but had es- caped (mainly during the period of in- tense whaling by Norwegians in 1883 to 1915). In total 46 Blue Whales had been entered in the database (2,2% of the to- tal), from the period 1426 till 2011 (Tab. 1). Distribution of findings are from all around Iceland, while majority is from the northern parts of the country (Fig. 3). One of these whales was salvaged and now is its skeleton on display at the Whale Museum in Húsavík (Figs 4-5). Many other whales in the database were reported as baleen whales only (n=107). Although precise species is unknown many of these whales are believed to be Blue Whales, as indicated by the Icelan- dic names that have been used by find- ers, while others could relate to two or more species. Comparing numbers as reflected in the database about twice as many Blue Whales were recorded from the 18th century as the 19th century. This is believed to mirror the large popula- tion decline from the late 18th century to the 19th century due to whaling opera- tions by Norwegians. (3) A literature search was made of whale remains found during exca- vations of middens and ancient farm- steads. Whale bones were reported in 72% of the 110 publications examined, of which 66% were reported as uni- dentified but only 6% identified to spe- cies, some relating to the same findings. Whale bones are notoriously difficult to identify to species using morpho- logical features, except perhaps skull and teeth. Therefore, recent molecular techniques will undoubtedly revolu- tionize species identification of marine mammals found during excavations in the next years to come. (4) Molecular methods for species identification are rather recent, not the least those using collagen and mito- chondria. Not much has been written on these methods in Icelandic. Therefore, a detailed overview of these methods is given in the text for Icelandic readers. Whaling with harpoon has been car- ried out for much of the period since Iceland was settled by man shortly be- fore year 1000. Legal codes regarding stranded whales found with harpoon, has been in force since the early law books in the 12th century. Yet, the catch- ing of Blue Whales did not take off until in the late 18th century, or after the ex- plosive harpoon had been invented by the Norwegian Foyn. Many harpooned whales escaped from the whalers were later found stranded or afloat at sea. A general agreement is among whale researchers that the Blue Whale popul- ation decreased drastically during the Norwegian whaling period 1883-1915. During that period the maximum of 327 animals were killed in a year, but about 6500 in all. A world ban on killing Blue Whales has been in force since 1960. Whaling is not the only reason why greater numbers of dead whales were recorded in the 18th century versus dur- ing the 19th. Climate was particularly ad- verse during the last decades of the 18th century, with the coasts of the North and East frequently becoming ice-locked, with detrimental effects for various whale species, such as Blue Whales. Although Blue Whales (Figs 6-7) have been protected in Iceland for over 60 years, the population increase has been slow. Population size was estimated about 3000 animals in 2015, probably still well below the numbers before industrial whaling started before 1900. Although mortality factors like hunting and ice con- ditions are non-existent or less now, other factors such as modern fishing effort, large fleet and advanced gear could still deflate population recovery. 135 Ritrýnd grein / Peer reviewed
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