Tuesday, January 5, 2021

Pacific Blue eyed fish from Australia to - some history of Austria !!

Fishes are attractive ! … watching them swim is soothing to mind .. .. there are thousands of varieties in the Sea, river, ponds and more .. this is more about Aquarium fish – freshwater variety.  In general, I have seen – Guppies (with beautiful tail – some coloured); Mollies; Platys; Sword tails; Barbs, Angel fish, Cichlids, Goldfish, Carp and the like .. .. was reading something on ‘Pacific Blue eyed fish’ and the history behind this is amazing !


As the name suggests, the fish’s eyes are a beautiful luminescent blue. Pacific Blue-eyes are carnivorous fish, particularly suited for garden ponds and aquariums.  Pacific Blue-eyes, like guppies,  help control mosquitoes by feeding on the larvae. Frog friendly – does not generally eat tadpoles.  The Pacific Blue Eye has a semi-transparent body that can vary in colour from pale olive, yellow to bluish. As the common name suggests, the iris of the Pacific Blue Eye is blue. The operculum and belly region are silvery. There is often a series of pearly spots along the side of the body.

Charlotte of Belgium (1840 –  1927) was a Belgian princess who became Empress of Mexico when her husband accepted the Imperial Throne of Mexico and reigned as Maximilian I of Mexico.   Maximilian I (Ferdinand Maximilian Joseph Maria was an Austrian archduke who reigned as the only Emperor of the Second Mexican Empire from 10 April 1864 until his execution on 19 June 1867.

In 1867,  Carlota left for Miramare, Maximilian's castle near the Imperial Free City of Trieste in the Austrian Littoral, an Austrian-ruled part of north-eastern Italy. On the journey there, Carlota's mental health showed signs of worsening—passing by a farmer, she became convinced that it was an assassin after her and persistently shouted at her coachman to drive faster. She was seeking an audience  with Pope Pius IX in Rome. On the way to Rome she showed further signs of deteriorating mental health;   she felt unwell and insisted that it was due to being poisoned by spies and traitors of Napoleon III among them.  She did meet  Pope Pius IX but he was reluctant to use his influence to intervene with Napoleon III on her empire's behalf. She became despondent and distant thereafter, overwhelmed by despair and paranoia, and remained within her hotel for the next two days.  She stayed overnight in the Vatican, while she rested,  the Emperor of Austria and the King of the Belgians sent delegations to Miramare Castle.  The King sent Jan Frans Bulckens,   a Belgian psychiatrist, to his sister and a medical team decided that the empress could not be told of the execution of her husband. With medical approval, Queen Marie Henriette gave her sister-in-law a faked telegram from her husband to come back to Brussels. Historians think that after the death of the Emperor in Mexico, Charlotte only had the status of a rich dowager.  


 Charlotte Empress of Mexico (from wiki commons)

 

Approximately 30,000 copies of Karl von Scherzer's book on the circumnavigation of the world of the frigate Novara were sold, a huge number in that era. It is considered the second most successful popular scientific work in the German language in the 19th century; second only to Alexander von Humboldt's 5-volume Cosmography. SMS Novara was a sail frigate of the Austro-Hungarian Navy most noted for sailing the globe for the Novara Expedition of 1857–1859 and, later for carrying Archduke Maximilian and wife Carlota to Veracruz in May 1864 to become Emperor and Empress of Mexico.

The circumnavigation of the earth from April 1857 to August 1859 by Novara was one of the most important journeys for what became the Naturhistorisches Museum in Vienna.  A number of eminent natural scientists joined the voyage, including Georg Ritter von Frauenfeld, curator in the invertebrate department of the Imperial museums.  The Natural History Museum Vienna  is a large natural history museum located in Vienna, Austria, considered one of the most important natural history museums worldwide.  The museum's 39 exhibition rooms cover 8,460 square meters and present more than 100,000 objects. It is home to 30 million objects available to more than 60 scientists and numerous guest researchers who carry out basic research in a wide range of topics related to human sciences, earth sciences, and life sciences. 

The Pacific blue-eye (Pseudomugil signifer) is a species of fish in the subfamily Pseudomugilinae native to eastern Australia. Described by Austrian naturalist Rudolf Kner in 1866, it comprises two subspecies that have been regarded as separate species in the past and may be once again with further study. It is a common fish of rivers and estuaries along the eastern seaboard from Cape York in north Queensland to southern New South Wales, the Burdekin Gap in central-north Queensland dividing the ranges of the two subspecies. A small silvery fish averaging around 3.25 cm in total length (1⅛–1⅜ in), the Pacific blue-eye is recognisable by its blue eye ring and two dorsal fins. It forms loose schools of tens to thousands of individuals. It eats water-borne insects as well as flying insects that land on the water's surface, foraging for them by sight. The Pacific blue-eye adapts readily to captivity.

                        Austrian naturalist Rudolf Kner described the species in 1866,  from a specimen collected in Sydney in 1858 during the course of the Novara Expedition and taken to Vienna by the SMS Novara.    Variable across its range, the Pacific blue-eye is considered to be a single species, though it has been split by some into northern signata and southern signifer, with the former found from Ross River northwards and the southern from the Calliope River south.  Within the northern population, five distinct lineages (or subclades) have been identified: one from Ross River and Herbert River, a second from Johnstone, Barron and Tully Rivers, a third from Mulgrave/Russell River and Trinity Inlet, a fourth from Daintree and Mossman Rivers and a fifth from Low Isles and Cape Melville.  

The Pacific blue-eye generally reaches a total length of around 3–3.5 cm (1 1⁄8–1 3⁄8 in) long; males can reach 8.8 cm (3 1⁄2 in) and females 6.3 cm (2 1⁄2 in).   The elongate body is partly transparent and pale yellow or olive with a silver operculum and belly. The scales are relatively large and longer vertically than horizontally. The eye is large and has a blue iris. There are two dorsal fins, the first arising in line with or just posterior to the longest pectoral fin ray. The forked tail fin has rounded tips.  The Pacific blue-eye is found from Narooma in southern New South Wales north to the Rocky River in Cape York, though it is uncommon in eastern Cape York. It lives in small, generally slow moving, streams to estuaries, as well as dune lagoons and salt marshes. It is also found in brackish and marine waters on some Queensland offshore islands such as Hinchinbrook Island, Lizard Island, Low Island and Dunk Island.  

                    It can also be found in tidal pools that become isolated from rivers at low tide. The Pacific blue-eye also forages in mangroves.  These fishes are  found in loose schools of tens to thousands of fish. They  can survive in a wide range of water salinities from fresh-water to marine environments. It responds to changes in salinity (and resulting change in buoyancy) by changing the volume of its swim bladder, which takes up to 6 hours and 40 minutes when salinity is reduced and around 5 hours when it is increased. In the meantime, the fish can swim with a head-up or head-down posture, which either increases or decreases buoyancy respectively. This adaptation helps the fish in the range of salinities it encounters in its estuarine environment.  In a school of Pacific blue-eyes that is threatened, a few individuals accelerate and change direction, which initiates an escape wave that spreads through the whole cohort.

Interesting ! 

With regards – S. Sampathkumar

5.1.2021. 

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