Tag Archives: fishes

The colligative effects of solutes in seawater (around 450 mM) depresses sea water freezing point to –1.9°C , while ordinary teleost blood (much more dilute) freezes at –0.4°C. So to avoid the blood and all tissues freezing solid, marine coldwater teleosts produce small anti-freeze proteins in the scales, skin, fins, …

Different fishes have very different lifestyles, so it is not surprising that the properties of their blood vary according to metabolic demands, and the way that the fish acquires O2 and excretes CO2. For example, blood in active fishes such as scombroids must have a much higher O2 capacity than …

A remarkable variety of accessory pumps occurs in the venous circulation of different fishes. These range from the portal heart of hagfishes behind the liver which has cardiac-type muscle and resembles the atrium of the main heart, with an ECG with P and T waves; to the caudal hearts of …

Fish hearts are S-shaped and four-chambered with, from behind forwards, sinus venosus, atrium, ventricle and either a bulbus or conus leading to the ventral aorta. We have already seen that some airbreathing fishes have a double circulation (the Japanese mudfish, Channa argus, even having a double ventral aorta), but only …

The oxygen acquired (from water or air), and the carbon dioxide excreted at the gills, have to be transported around the body by the circulation of the blood. In fishes using the gills as a gas exchanger, the primary circulation is single, blood leaves the heart to pass first through …

The variety of freshwater fishes is striking, for they show radiations into different habitats with some of the most extraordinary adaptations of all fishes. The African mormyrids and the South American gymnotids, for example, have independently evolved amazingly specialized electrical signaling systems for use in crowded and turbid waters, and …

Diversity of Freshwater Fishes Despite representing only a miniscule (0.0093% according to Horn, 1972) part of the world’s aquatic habitat, freshwaters contain a disproportionate number of species (over 40%, again according to Horn, 1972). Unlike the oceans, which constitute broad, uninterrupted expanses of water, freshwater habitats tend to be much …

Epipelagic Fishes The open ocean beyond the continental shelf covers nearly two-thirds of the surface of the Earth, and some 2500 species are found there, distributed vertically from the uppermost waters to the greatest depths, about half being benthic, half pelagic. Near the surface is the euphotic zone, where light …

Warm-water Fishes By far the greatest number (80%) of the 10 000 or so species of fishes in shallow seas live in warm temperate or tropical waters, most associated with coral reefs and atolls, in waters where mean temperatures during the coldest part of the year do not fall below …

Introduction Fishes live in virtually every watery habitat found on earth. The world’s deepest living fish (Abyssobrotula galatheae) was found in the Puerto Rican Trench at a depth of 8372 meters while the Tibetan stoneloach (Triplophysa stoliczkai) lives at altitudes over 5200 meters in the Himalaya. The habitats of fishes …