Fish Anatomy

FISHERIES BIOLOGY AND counseling External angle variant The following illustration of a large oral cavity low shows some of the habitual external features that argon apply to describe the differences among angle species. Fish atomic number 18 animals that be cold- pitched, nourish quintuples and a dressingb iodin(a). Most tip puzzle scales and breathe with branchias. There be about 22,000 species of look for that began evolving roughly 480 cardinal years ago. The largemouth billustrated abovethe ordinary torp equal (fusi phase angle) shape associated with many look fores used by the fish to maintain its position, question, bespeak and eat up.They be either angiotensin-converting enzyme quintets alonthe centerline of the fish, such(prenominal) as the dorsal (back) fins, caudal (tail) fin and anal fin, or pai rubor fins, which take the pectoral (chest) and pelvic (hip) fins. Fishes such as catfish tolerate a nonher fleshy lobe behind the dorsal fin, c alled an adipose (fat) fin that is not illustrated here. The dorsal and anal fins primarily att devastation to fish to not twine over onto their grimaces. The caudal fin is the main fin for propulsion to move the fish forward. The paired fins financial aid with stee besiege, stoppingand hovering.Scales in almost boney fishes (most freshwater fishes other(a)wise than gar that brace ganoid scales, and catfish which eat no scales) are either ctenoid or rounded. Ctenoid scales have jagged edges and cycloid have smooth locomote edges. Ctenii are tiny, comblike projections on the exposed (posterior) edge of ctenoid scales. Bass and most other fish with spines have ctenoid scales represent of connective tissue covered with calcium. Most fishes too have a very significant mucous secretion layer covering the body that helps prevent infection.Anglers should be careful not to rub this slime murder when handling a fish that is to be released. free state Envirothon 1 In many f reshwater fishes the fins are supported by spines that are unbendable and whitethorn be rather scheming thus acting a defensive role. Catfish have notably hard sharp fins that anglers should be wary of. The emollient dorsal and caudal fins are composed of rays, as are portions of other fins. Rays are slight rigid and frequently branched. The gills are the breathing apparatus of fish and are passing vascularized giving them their bright red cover.An operculum (gill cover) that is a flexible bony plate protects the sensitive gills. Water is inhaled through with(predicate) the mouth, passes over the gills and exhaled from beneath the operculum. Fish see through their eyes and can detect color. The eyes are rounder in fish than mammals because of the refractive index of water and focus is achieved by mthe lens in and out, not distorting it as in mammals. water and can be quite sensitive. Eels and catfish have mathematical functionicularly well developed senses of smell. larger it is the bigger the prey it can consume.Fish hava sense of taste and may exemplification items to taste them before swallowing if they are not obvious prey items. any(prenominal) are primmostly other fish). The merchandise grass carp is one and only(a) of the few large fishes that are primarily herbivorous (eating plants). Fish may or may not have teeth depending on the species. Fishchain pickerel and gar have obvious canine-shaped teeth. early(a) fish have less obvious teeth, such as the cardiform teeth in catfish which timber like a loopy neighborhood at the campaign of the mouthor vomerine teeth that are tiny patches of teeth, for example, in the roof of a stripe bass mouth.Grass carp and other minnows have pharyngeal teeth modified from their gill arches for grinding that are fixed in the throat. that are open to the water through a series of pores (creating a line on the side of the fish). The lateral line primarily senses water currents and pressure, and movemen t in the water. immediately in front of the anal fin. are used to describe the differences in the midst of fish that are described in to a greater extent detail below. doctor Envirothon 2 front of thhollow and house and protect the fine spinal cord. SPINAL pile Cbrain, as well as in BRAIN Thbehaviors attended here.LATERAL LINEOsense reed organs detectunderwater vibrations and is capable of determinthe direction of their source. (See supply 8 of The City Fisher for m reading. ) SWIM (or AIRBLA hollow, gas-fillbalance organ a fish to conserve energyby maintaining neutral airiness (suspending) in water. Fish caught fromvery thick(p) water some snips need to have air releasreleased and return to deep water, dusurface. Species of fish that do not possess a overwhelm bladder sink to the bottom if they stop swimming. GILLS Aif the fishKIDNEY ed from their swim bladder before they can be idney is alsbody, allowing sure(p) fish species to exist in freshwater or saltwater, and in s ome cases (such assnook or tarpon) both. Maryland Envirothon 3 STOMACH AND INTESTINES Break rarify (digest) fo Fish such as tilapia that are herbivomatter is commonly tough and fibrous and more(prenominal) difficult to break down into usable components. A great commode about fish feed habits can be determined by examining stomach contents. PYLORIC CAECA This organ with fingerlike projections is located upright the junction of the stomach and theindigestion, may functio VENT The site of waste extermination from the fishs body.LIVER This important organ has a number of functions. It abrimportantas playing a role in nitrogen (waste) excretion. HEART Circulates blood throughout the body. Oxygen avakidneys an GONADS (REPRODUCTIVE ORGANS) In adult female bass, the bright oranbufertilizing the eggs, are much smaller and wh(or roe) of certain fish are considered a delicacy, as in the case of caviare from sturgeon. MUSCLES Provide movement and loco drive. This is the part of the fish that is usually eaten, and Measuring a Fish of the fish with the mouth closed and the tail fin aying along a tape amount, then pinch the tail fin closed and determine the totality distance, do NOT pull a flexible tape measure along the curve of the fish. Conversely, most marine (saltwater regulations) refer to the fork length, and scientists oftenuse standard length which is to the end of the fleshy part of t Maryland Envirothon 4 aby minor damage to the tanor does it give too much creditto a fish for the relatively light weight tail when calculatingfishs condition. childs play is best calculated with a fabric ruler, such as tailors use.It can also be determined by force a string around the fish at its widest point marking wherethe string overlaps and then mthe overlap points on a conventional ruler. Knowing the snap is important when tryingcertify a fish for a record, and provides efficacious information Using total length and girth you can get a rough estimate of a fishs weight using diverse formulas. Length-Weight Formulas to Estimate Fish Weights biologists use. The equation is Log (weight in grams)= -4. 83 + 1. 923 x Log (total length in millimeters) + 1. 57 x Log (girthmillimeters). A 22 long bass w A quick, though very rough, estimate of torpedo shaped fish like unfledged bass can be obtained by using Total Length (in inches)-squared, times girth (in inches) divide by 1200. A 22 long Another common land option used for estimating bass weights is Girth (in inches)-squared, times length (in inches) dual-lane by 800. A 22 long bass with a girth of 15 How Fish go alternately on each side first toward one side and then toward the other, results in a series of wavers travel down the fishs body.The elevate part of each wave thrusts against the water and propels the fish forward. Maryland Envirothon 5 This type of movement is quite clearly seen in the freshwater eel. Because movement of the head back and forth exerts drag, which consumes addit ional energy and slows travel, a great many fishes have modified this snakelike motion by keeping the waves very small along most of thelength of the body, in some cases showing no obvious movement at all, and then increasing them sharply in the tail region.It is the end of the traveling waves that moves the tail forcefully backand forth, providing the main propulsion for forward motion. A simpler form of tail propulsion seen in such inflexible-bodied fishes as the trunkfish, which simply alternates contractions of all the muscle blocks on one side of the body with those on the other side, causing the tail to move from side to side like a sculling paddle. Some of the predatory bony fishes are the fastest swimmers they can cruise at speeds that are between 3 and six times their body lele0. 8 km/hr (0. mph), swim very slowly others, such as the salmon, which may reach a sustainespeed of 13 km/hr (8 mph), move much express and it has been estimated that tuna may reach speeds of 80 km /hr (50 mph), and swordfish, 97 km/hr (60 mph). admission to Aging Fish What Are Otoliths? directly behind the brain of bony fishes. There are common chord types of o 1. Sagittathe largest of the 3 pairs of otoliths involved in the detection of sound and process of hear 3. Lapillusinvolved in the detection of gravitational force and sound (Popper and Lu 2000) re are many different shapes and sizes of otoliths differenOtoliths are important to scientific age and growing studies. This figure shows the growth go of a sagittal otolith segment viewed under reflective light. The darker area or translucent zone represents a period of fast growth. The whiter area or muddyzone represents a period of slower growth. The age of the fish is estimated by reckoning the annuli, or opaque plentys, of the thin sections, as one would count rings on a tree to determine its age. Maryland Envirothon 6 Before age data can be used, the mode of estimating age by counting annuli must be validated for each species to which it is applied.There are several ship canal to validate age, or read that one annulus is equal to one year. Most obvious readiness be to simply rear fish from spawn, sacrifice the fish after a few years, and contrast the number of rings to the cognize age of those fish. This process can be time consuming and expensive. It also creates the possibility of abnormal growth patterns caused by laboratory settings (Campana, 2001). Although this method may not be applicative for validating annular ring formation, a similar method is effective in validating day-to-day ring formation (Campana and Neilson, 1985).To neutralise the effects of long-term laboratory exposure, tag and release of wild fish can be useful in validating annulus deposition. This figure shows the fluorescent tag of a common snook otolith. A captured common snook was injected with oxytetracycline (OTC), a chemical that is incorporated into calcium-rich structures including otoliths. The fish w as then tag and released. Seven years later, the fish was recaptured, sacrificed, and processed for aging. The OTC, which binds to the calcium in the otolith, appears as a glowing band when the otolith is viewed using fluorescence microscopy.The number of annuli between capture and recapture is also seven. Information like this is key to linking a single annulus to one year of growth, but such information relies heavily on time and chance. The age data self-collected from otolith examinations allow scientists to model growth rates, maximum age, age at maturity, and the cause of future generations. Literature write Florida Fish and Wildlife Conservation Commission. http//www. floridamarine. org/features/view_article. asp? id=21978 and http//myfwc. com/Fishing/Fishes/anatomy. html. Fish and Wildlife ResearchFish AnatomyFISHERIES BIOLOGY AND MANAGEMENT External Fish Anatomy The following illustration of a largemouth bass shows some of the common external features that are used to d escribe the differences among fish species. Fish are animals that are cold-blooded, have fins and a backbone. Most fish have scales and breathe with gills. There are about 22,000 species of fish that began evolving around 480 million years ago. The largemouth billustrated abovethe typical torplike (fusiform) shape associated with many fishes used by the fish to maintain its position, move, steer and stop.They are either single fins alonthe centerline of the fish, such as the dorsal (back) fins, caudal (tail) fin and anal fin, or paired fins, which include the pectoral (chest) and pelvic (hip) fins. Fishes such as catfish have other fleshy lobe behind the dorsal fin, called an adipose (fat) fin that is not illustrated here. The dorsal and anal fins primarily help fish to not roll over onto their sides. The caudal fin is the main fin for propulsion to move the fish forward. The paired fins assist with steering, stoppingand hovering.Scales in most bony fishes (most freshwater fishes o ther than gar that have ganoid scales, and catfish which have no scales) are either ctenoid or cycloid. Ctenoid scales have jagged edges and cycloid have smooth rounded edges. Ctenii are tiny, comblike projections on the exposed (posterior) edge of ctenoid scales. Bass and most other fish with spines have ctenoid scales composed of connective tissue covered with calcium. Most fishes also have a very important mucus layer covering the body that helps prevent infection.Anglers should be careful not to rub this slime off when handling a fish that is to be released. Maryland Envirothon 1 In many freshwater fishes the fins are supported by spines that are rigid and may be quite sharp thus playing a defensive role. Catfish have notably hard sharp fins that anglers should be wary of. The soft dorsal and caudal fins are composed of rays, as are portions of other fins. Rays are less rigid and frequently branched. The gills are the breathing apparatus of fish and are highly vascularized givin g them their bright red cover.An operculum (gill cover) that is a flexible bony plate protects the sensitive gills. Water is inhaled through the mouth, passes over the gills and exhaled from beneath the operculum. Fish see through their eyes and can detect color. The eyes are rounder in fish than mammals because of the refractive index of water and focus is achieved by mthe lens in and out, not distorting it as in mammals. water and can be quite sensitive. Eels and catfish have especially well developed senses of smell. larger it is the bigger the prey it can consume.Fish hava sense of taste and may sample items to taste them before swallowing if they are not obvious prey items. Some are primmostly other fish). The imported grass carp is one of the few large fishes that are primarily herbivorous (eating plants). Fish may or may not have teeth depending on the species. Fishchain pickerel and gar have obvious canine-shaped teeth. Other fish have less obvious teeth, such as the cardifo rm teeth in catfish which feel like a roughened area at the front of the mouthor vomerine teeth that are tiny patches of teeth, for example, in the roof of a striped bass mouth.Grass carp and other minnows have pharyngeal teeth modified from their gill arches for grinding that are located in the throat. that are open to the water through a series of pores (creating a line along the side of the fish). The lateral line primarily senses water currents and pressure, and movement in the water. immediately in front of the anal fin. are used to describe the differences between fish that are described in more detail below. Maryland Envirothon 2 front of thhollow and house and protect the delicate spinal cord. SPINAL CORD Cbrain, as well as in BRAIN Thbehaviors processed here.LATERAL LINEOsense organs detectunderwater vibrations and is capable of determinthe direction of their source. (See Issue 8 of The City Fisher for minformation. ) SWIM (or AIRBLA hollow, gas-fillbalance organ a fish to conserve energyby maintaining neutral buoyancy (suspending) in water. Fish caught fromvery deep water sometimes need to have air releasreleased and return to deep water, dusurface. Species of fish that do not possess a swim bladder sink to the bottom if they stop swimming. GILLS Aif the fishKIDNEY ed from their swim bladder before they can be idney is alsbody, allowing certain fish species to exist in freshwater or saltwater, and in some cases (such assnook or tarpon) both. Maryland Envirothon 3 STOMACH AND INTESTINES Break down (digest) fo Fish such as tilapia that are herbivomatter is usually tough and fibrous and more difficult to break down into usable components. A great deal about fish feeding habits can be determined by examining stomach contents. PYLORIC CAECA This organ with fingerlike projections is located near the junction of the stomach and theindigestion, may functio VENT The site of waste elimination from the fishs body.LIVER This important organ has a number of funct ions. It abrimportantas playing a role in nitrogen (waste) excretion. HEART Circulates blood throughout the body. Oxygen avakidneys an GONADS (REPRODUCTIVE ORGANS) In adult female bass, the bright oranbufertilizing the eggs, are much smaller and wh(or roe) of certain fish are considered a delicacy, as in the case of caviar from sturgeon. MUSCLES Provide movement and locomotion. This is the part of the fish that is usually eaten, and Measuring a Fish of the fish with the mouth closed and the tail fin aying along a tape measure, then pinch the tail fin closed and determine the total length, do NOT pull a flexible tape measure along the curve of the fish. Conversely, most marine (saltwater regulations) refer to the fork length, and scientists oftenuse standard length which is to the end of the fleshy part of t Maryland Envirothon 4 aby minor damage to the tanor does it give too much creditto a fish for the relatively light weight tail when calculatingfishs condition. Girth is best meas ured with a fabric ruler, such as tailors use.It can also be determined by drawing a string around the fish at its widest point marking wherethe string overlaps and then mthe overlapping points on a conventional ruler. Knowing thegirth is important when tryingcertify a fish for a record, and provides useful information Using total length and girth you can get a rough estimate of a fishs weight using various formulas. Length-Weight Formulas to Estimate Fish Weights biologists use. The equation is Log (weight in grams)= -4. 83 + 1. 923 x Log (total length in millimeters) + 1. 57 x Log (girthmillimeters). A 22 long bass w A quick, though very rough, estimate of torpedo shaped fish like young bass can be obtained by using Total Length (in inches)-squared, times girth (in inches) divided by 1200. A 22 long Another common option used for estimating bass weights is Girth (in inches)-squared, times length (in inches) divided by 800. A 22 long bass with a girth of 15 How Fish Swim alternatel y on each side first toward one side and then toward the other, results in a series of waves traveling down the fishs body.The rear part of each wave thrusts against the water and propels the fish forward. Maryland Envirothon 5 This type of movement is quite clearly seen in the freshwater eel. Because movement of the head back and forth exerts drag, which consumes additional energy and slows travel, a great many fishes have modified this snakelike motion by keeping the waves very small along most of thelength of the body, in some cases showing no obvious movement at all, and then increasing them sharply in the tail region.It is the end of the traveling waves that moves the tail forcefully backand forth, providing the main propulsion for forward motion. A simpler form of tail propulsion seen in such inflexible-bodied fishes as the trunkfish, which simply alternates contractions of all the muscle blocks on one side of the body with those on the other side, causing the tail to move fro m side to side like a sculling paddle. Some of the predatory bony fishes are the fastest swimmers they can cruise at speeds that are between three and six times their body lele0. 8 km/hr (0. mph), swim very slowly others, such as the salmon, which may reach a sustainespeed of 13 km/hr (8 mph), move much faster and it has been estimated that tuna may reach speeds of 80 km/hr (50 mph), and swordfish, 97 km/hr (60 mph). Introduction to Aging Fish What Are Otoliths? directly behind the brain of bony fishes. There are three types of o 1. Sagittathe largest of the 3 pairs of otoliths involved in the detection of sound and process of hear 3. Lapillusinvolved in the detection of gravitational force and sound (Popper and Lu 2000) re are many different shapes and sizes of otoliths differenOtoliths are important to scientific age and growth studies. This figure shows the growth rings of a sagittal otolith section viewed under reflective light. The darker area or translucent zone represents a p eriod of fast growth. The whiter area or opaquezone represents a period of slower growth. The age of the fish is estimated by counting the annuli, or opaque bands, of the thin sections, as one would count rings on a tree to determine its age. Maryland Envirothon 6 Before age data can be used, the method of estimating age by counting annuli must be validated for each species to which it is applied.There are several ways to validate age, or prove that one annulus is equal to one year. Most obvious might be to simply rear fish from spawn, sacrifice the fish after a few years, and compare the number of rings to the known age of those fish. This process can be time consuming and expensive. It also creates the possibility of abnormal growth patterns caused by laboratory settings (Campana, 2001). Although this method may not be practical for validating annular ring formation, a similar method is effective in validating daily ring formation (Campana and Neilson, 1985).To avoid the effects of long-term laboratory exposure, tag and release of wild fish can be useful in validating annulus deposition. This figure shows the fluorescent tag of a common snook otolith. A captured common snook was injected with oxytetracycline (OTC), a chemical that is incorporated into calcium-rich structures including otoliths. The fish was then tagged and released. Seven years later, the fish was recaptured, sacrificed, and processed for aging. The OTC, which binds to the calcium in the otolith, appears as a glowing band when the otolith is viewed using fluorescence microscopy.The number of annuli between capture and recapture is also seven. Information like this is key to linking a single annulus to one year of growth, but such information relies heavily on time and chance. The age data gathered from otolith examinations allow scientists to model growth rates, maximum age, age at maturity, and the trend of future generations. Literature Referenced Florida Fish and Wildlife Conservation Co mmission. http//www. floridamarine. org/features/view_article. asp? id=21978 and http//myfwc. com/Fishing/Fishes/anatomy. html. Fish and Wildlife Research