Monitoring fishes is probably the hardest technique to learn because many species are highly mobile and counts can vary enormously from day to day. If divers swim into an area, especially where fishing is done, then many fish will be scared away. Some fish hide or are cryptic as a normal part of their bevhavior. If visibility is poor due to high turbidily or low light levels, then counts may not be easy to carry out. The density of fish populations at any given time will vary depending on the swimming behavior and territory of the fish. The size of the area being counted needs to be considered in context of how far that particular species of fish swims. For example, our RC surveys will present a good view of semi-sedentary fish such as grouper, but could represent a poor estimate of highly mobile fish such as tuna.
Reef Check uses 4 x 5 m wide by 20 m long by 5 m high belt (or tunnel) transects for our fish survey. Each 20 m transect is called a replicate or segment so one whole Reef Check transect line is comprised of 4 replicates. The fish survey MUST be the first survey done because fish are easily scared by divers. The ideal time to start this survey is between 9-10am and it will take up to 60 minutes to complete the 4 x 20 m replicates.
The line deployment will scare some fish into hiding, so it is important that one waits 15 minutes to allow the fish to recover and resume normal activity It is important to keep in close contact with your buddy and maintain good visual skills. If both buddies are recording data, it is important they communicate so that fish are not double counted during each transect
Remember - we wait for 1 minute at 5 m intervals to let the fish settle, but counting takes place both while swimming the transect as well as while stopped at each 5 meter mark To check belt width estimates – fully extend arms and fins to find the 2.5 m length. Careful not to disturb the fish in the next 5 m!! We recommend 2 divers both record data, but one experienced diver may record data for the whole 5 m belt. Remember to share your counting time equally across the belt. If you share the survey - communicate with your buddy you count fish that swim across the transect. Avoid double counting. Good practices involve the buddy pair splitting the transect in half, with the meter tape as the dividing line so each buddy pair counts only an area 2.5 meters wide. To determine who should count the mobile fish, a good rule of thumb is that if the fish swims from your side of the line to your buddy’s side, you count it. If a fish swims from your buddy’s side of the line to yours, your buddy counts it. This reduces double counting.
Any encounters of humphead wrasse or bumphead parrotfish are recorded, regardless if they are in the transect area or not. Make notes in the comments section if observed outside the transect perimeter Any megafauna observed is recorded as well. These counts go in the comments section at the bottom of the data sheet. We want these sightings because all these animals are now rare.
The standard Reef Check survey of 4 x 20 m long by 5 m wide replicates carried out at two depths is designed to capture a snapshot of fish populations for regional and global comparison. In order to obtain reliable estimates of Reef Check target fish families it is necessary to increase both the number of Reef Check surveys to up to 3 full Reef Check surveys, that is 24 replicates at each site, up to 4 times each year.
Example of data sheet. Column one is the list of indicators. Column two is the first 20 m of the transect. Note the 5 m gap before the next transect begins in column 3. There are a total of 4 replicate 20 meter surveys.
Notice we only count grouper and parrotfish over certain sizes. This is to aid in determining overfishing for these groups. Some species of grouper do not grow larger than 30 cm. Many fish smaller than these size classes are immature and pre-reproductive. If there are no large parrotfish or grouper then the area is most likely heavily fished.
This diagram shows the external parts of a fish that are often used to help differentiate species and families. Key ID characteristics for Reef Check indicators will also include color, body shape, head shape, lip size, and shape of the tail fin (caudal fin), pectoral and dorasl fins. Other important ID characteristics are the swimming motion used and behavior.
Scientists use scientific names so for clarity everywhere in the world. Common names tend to be different in different regions or countries. Grouper are called cod or coral trout in Australia or garupa in other locations. Most adults grow to about 30-70 cm length from their mouth to tail tip and some species can reach 2m in length. They are carnivorous fish with a thick peduncle (tail base) and large, wedge shaped tail. Bottom lip protrudes so they look as if they have an attitude problem. Their mouth contains rows of small, sharp teeth, and they feed on smaller fish and crustaceans. These fish are a highly prized food fish hence typically one of the first fish to suffer overfishing.
The underside of their body is almost flat like other bottom dwellers. They are often found motionless on the bottom and often in the mouths of barrel sponges, waiting for prey to come into their vicinity. They position themselves like this because they attack their prey from below. They have large eyes that are set at the top of their head that allow them to see above them. They have distinctive spines on their dorsal (top) fin. This fish has its mouth open for cleaning. Remember we only include fish 30 cm or larger.
When divers approach they will often swim away and duck into a hole in the reef or hide behind a rock. Their swimming style is smooth and relatively rapid. To an approaching diver, it seems as if they just flick their tail then glide away behind a rock. They are important food fish, thus, low numbers is an indication of overfishing by nets, spearfishing, blast and/or poison fishing. On a healthy reef they are very common and up to 20 large fish would be encountered on one Reef Check transect.
These fish are also known as the Humpback Grouper and juveniles are called Panther Grouper in the aquarium trade. They are characterised by having a flattened head profile (the head looks too small for the body) followed by a hump, hence the name. They are a mixture of white and beige with black spots and can grow to 70cm. Generally found in lagoon and seaward reefs, though are more common on dead or silty areas than clear offshore areas. These fish are so un-afraid of humans that they are typically quickly spearfished and hook and line fished out of a reef. They often hover in the water column using their pectoral fins to maintain position. They may hide under plate corals or shallow overhangs. Can often be found in pairs so if you see one, have a quick look for another! The adults are a highly valued food fish in the Indo-Pacific and juveniles are popular aquarium fish. They are rare nowadays as both adults and juveniles are removed.
These are medium to large fish (adults are generally between 40-80cm in length) with low set mouths (as with grouper). They have thick lips, especially the upper lip, which protrudes over the bottom (the opposite to the grouper). Their lips are probably their best distinguishing feature. To distinguish them from groupers: their foreheads slope more steeply and appear as a quarter of a circle, so that they are thicker fish from top to bottom. This shape positions their eyes in a more forward position, which is an indication towards their behaviour in that they search for food rather than wait for it to come their way. Imagine they are an upside down butter-knife – flat on the bottom and rounded on top. They are normally on the move somewhere but may seem as if they’ve not quite decided on where they are going. They swim with an undulating motion with a ripple from top to bottom in their tail fin. They often remain inactive during the day with their head facing into the current, or hiding in caves or crevasses. They are regularly encountered in groups or on their own.
On looking at their eyes, they seem as if they are trying to look behind them and as though they are a little bit alarmed about something (the eyes of grouper lie near the top of their body for upward vision while sitting motionless). Their peduncle appears much thinner than that of the grouper in relation to their body height (top to bottom) and their tails have a very slight indentation. Sweetlips are a common food fish (although not in Australia). Low numbers are an indication of overfishing.
These are very common food fishes and naturally found in large groups Low numbers are an indication of overfishing. Many species range between 20-50cm in length. To distinguish snappers from sweetlips, first consider if there is a school of fish or just a few individuals. If a school of five or more then these are not sweetlips. If there are just a few, then look at their lips. Thin lips = snapper and thick lips = sweetlips. Finally, if there is still a question, the angle formed by the head of the snapper is smaller (more acute) than typical of the sweetlips. One can also look to their behavioural differences. In small number, snapper will typically dart away when disturbed whereas sweetlips, on the other hand, will act like a friendly dog, and just hang around.
Snappers can sometimes be confused with emperor fish (Lethrinidae). Emperors tails are very fork-shaped, the top of their head forms a straight line profile, and creates a sharp-looking nose, and they have a higher profile behind the head so that they appear more hump-shaped in the dorsal area than snappers. Emperors are almost always solitary while snappers tend to form schools above the reef.
Also called the Maori or Napoleon wrasse, these are among the largest of reef fish and can grow to more than 2m in length. The adults males are distinguished by the hump on their forehead and by their thickened lips, typical of many wrasse species. They are usually solitary and may swim deep when approached by divers unless they have been fed by divers and have a reduced sense of caution. They mainly feed on molluscs but can eat other well armoured and some toxic invertebrates, such as crown-of-thorns starfish or sea hares. Thus one of their functions in the ecosystem is to help keep the abundance of these otherwise inedible invertebrates in check. Immature males and females can be identified by the irregular lines crossing the face. They are caught using fish poison, typically cyanide. These fish are one of the highest priced fishes in the live food fish trade for Asia – a large fish will sell for US$10,000.
Parrotfish are closely related to wrasse and swim - in a similar fashion with their pectoral fins - their tail fin remaining still so they appear to be flying like a bird. Parrotfish are distinguished from wrasse by their fused, beaklike teeth (Wrasse have pointy teeth). The teeth of parrotfish are fused together to form what looks like a beak, hence the name parrotfish. The strong teeth are used to scrape algae off rock and bite chunks of corals. Often observed pooping out long streams of white sand. Males are brightly coloured and tend to hang out with a large group of more drab-coloured females.
The coral rock that is ingested along with live coral and algae is crushed into sand and excreted. They are the main producers of the sandy beaches that border tropical reefs.
The Bumphead is the largest of the Parrotfish, reaching 130cm in length. They typically feed in schools and may ram the corals with their head to break them and facilitate feeding. They leave big white scars on the reef where they have broken up live hard coral. These are much darker than the humphead wrasse and the fused teeth are very prominent.
Butterflyfish are small, disc-shaped fish that have a laterally compressed body, which enables them to gracefully move in-between branching corals and other reef outcrops. For locomotion, they primarily use their pectoral fins. This trait has, however, evolved at the expense of speed. They have small protruding mouths containing small, brush-like teeth that are adapted to carefully pick food from the reef. They feed on coral polyps, small invertebrates, fish eggs, plankton and/or filamentous algae. The various species of butterfly fish tend to share certain characteristics in their colouring and patterning. They tend to be black, white and yellow, although some have pale blue and red markings also. Most species have a black stripe running across their head that ‘hides’ their eyes from predators. Predators may look for eyes to determine the front from the back of their prey and will prefer to attack from the back from where they are less likely to be seen. In addition, many species of butterflyfish will have an eyespot to the rear of their body. This, again, acts to confuse their predator as to which is the front and the back. Bannerfish are included but Moorish Idols are not.
Butterflyfish and angelfish are often confused. Angelfish typically are more colorful than butterflyfish with frequent blues, reds and oranges. Angelfish typically reach 30 cm, much larger than the maximum size of butterflyfish which is typically 15 cm. Angelfish are solitary or in pairs whereas butterflies may form large schools. Angelfish are more elongate with dorsal and anal fins that trail beyond the body. Look for back-facing cheek spines on angelfish, these are not found on butterflyfish. Also pay close attention to the mouth structures. Butterflyfish will have elongated, pointy mouths with small lips while angelfish have larger lips and less protruding mouths.
Moorish idols have elongated noses, black, white and yellow coloration and compressed bodies, but they are not butterflyfish.
Bannerfish belong to the Butterflyfish family and are counted in Reef Check fish surveys, whereas Moorish Idols are not. The main distinction between bannerfish and Moorish Idols is the nose of the Moorish Idol. The Idol’s nose is elongate with long upper and lower jaws and has a yellow bridge above the nose outlined in black. The Idol also has very fine scales and a yellow coloration on the body whereas bannerfish have apparent scales and the yellow coloration is restricted to the fins. Moorish Idols have eyelash-looking projections above their eyes that interrupt the rounded profile of the fish. Bannerfish lack these projections and some have a notch cut out just below the eye. Moorish Idols have predominantly black or clear fins whereas bannerfish have yellow, black and white fins.
Eels tend to hide in holes on the reef – you’ll rarely see them swimming around. They are important for food in many parts of the world and a tourist attraction. Please don’t aggravate them as they have a nasty bite!
Indo-Pacific Fish ID Training Reef Check EcoDiver Course
<ul><li>Diver movements can scare fish </li></ul><ul><li>Water clarity and light </li></ul><ul><li>Spatial scale of survey vs swimming range of fish </li></ul><ul><li>Fish behavior patterns e.g. cryptic </li></ul><ul><li>Swimming speed - more fish will be seen by a diver who swims slowly </li></ul>Fish monitoring: What affects reliability of fish counts?
Fish monitoring methods <ul><li>Four 5 m wide by 20 m long by 5 m high belt (or tunnel) transects </li></ul><ul><li>First survey done </li></ul><ul><li>Ideal start time 9-10 AM </li></ul><ul><li>Takes about up to 60 minutes to complete </li></ul>
<ul><li>To conduct this survey: </li></ul><ul><li>Deploy the line first </li></ul><ul><li>Wait 15 minutes until fish resume normal activity </li></ul><ul><li>Work with a buddy to conduct surveys </li></ul>Fish monitoring methods
Fish monitoring methods <ul><li>Transect methods: </li></ul><ul><li>Lay line. Exit water and wait 15 minutes. </li></ul><ul><li>At beginning of line, wait 1 minute. During this time, check width of 2.5 m belt versus your body length. </li></ul><ul><li>Check your 20 cm and 30 cm size estimates against transect line </li></ul><ul><li>Swim at a SLOW and STEADY pace while counting </li></ul><ul><li>At 5 m mark wait again for 1 minute. Continue counting while you wait if new fish enter. Check belt estimations again. Communicate with your buddy. </li></ul>
<ul><li>Other useful tips: </li></ul><ul><li>Concentrate on your buoyancy </li></ul><ul><li>Make slow and careful movements </li></ul><ul><li>Coordinate with your buddy - ensure you get frequent eye contact </li></ul><ul><li>Don’t count fish twice </li></ul><ul><li>Make notes in comments section of any off transect sightings of humphead wrasse, bumphead parrotfish, or any megafauna (sharks, rays, turtles, etc.) </li></ul>Fish monitoring methods
Long-term fish monitoring <ul><li>For a snapshot, do one Reef Check survey (4 x 20 m replicates) at two depths (2- 6 m, >6 -12 m) </li></ul><ul><li>For detailed long-term monitoring, 3 full Reef Check surveys (24 replicates), up to 4 times each year. </li></ul>
Fish Belt Transect Form 0-20m 25-45m 50-70m 75-95m Butterflyfish (Chaetodontidae) Sweetlips (Haemulidae) Snapper (Lutjanidae) Barramundi cod ( Cromileptes altivelis ) Humphead wrasse ( Cheilinus undulatus ) Bumphead parrotfish ( Bolbometopon muricatum ) Other parrotfish (Scaridae) only >20 cm Moray eel (Muraenidae) Grouper (Serranidae) sizes (cm) (count ONLY >30cm): 0-20m 25-45m 50-70m 75-95m 30-40 cm 40-50 cm 50-60 cm >60 cm Total # grouper Rare animals sighted (type/#) Comments:
<ul><li>Grouper (all species - count all individuals that are larger than 30 cm and sized to the nearest 10 cm) </li></ul><ul><li>Barramundi cod </li></ul><ul><li>Snapper (all species) </li></ul><ul><li>Sweetlips (all species) </li></ul><ul><li>Butterflyfish (all species) </li></ul><ul><li>Humphead wrasse (off the transect records also) </li></ul><ul><li>Parrotfish (all species over 20 cm) </li></ul><ul><li>Bumphead parrotfish (off the transect records also) </li></ul><ul><li>Moray Eel </li></ul>Which Fish Do We Count?
Fish Identification Areas Lower jaw (mandible) Interorbital region Eye Upper jaw Dorsal fin (and spines) Caudal peduncle Caudal fin Anal fin Suborbital region Operculum (gill cover) Gill opening Pelvic fin Pectoral fin
Grouper Serranidae <ul><li>ID TIPS </li></ul><ul><li>Look for the protruding lower jaw </li></ul><ul><li>Eyes are close to the mouth and the top of the head </li></ul><ul><li>Wedge-shaped tail </li></ul><ul><li>Grow to 30-70 cm. Some to 2 m! </li></ul><ul><li>Carnivorous fish that feed on smaller fish and crustaceans. </li></ul>Photograph by Dean Miller Photograph by Dean Miller
<ul><li>Bottom dwellers - flat underside </li></ul><ul><li>Ambush predators - wait motionless </li></ul><ul><li>Eyes on the top of their head </li></ul>Grouper Serranidae Photograph by Dean Miller Photograph by Dean Miller Distinctive spines on their dorsal (top) fin.
Count grouper over 30 cm and size them to the nearest 10 cm Grouper Serranidae Photograph by Dean Miller Photograph by Undersea Explorer Photograph by Dean Miller Photograph by Gareth Stevens Photograph by Gareth Stevens
Barramundi Cod (Grouper) Serranidae Cromileptes altivelis Photograph by Dean Miller <ul><li>ID TIPS </li></ul><ul><li>Flattened head profile followed by a hump </li></ul><ul><li>Swim with pectoral fins </li></ul><ul><li>Very friendly not shy </li></ul><ul><li>(Also known as the Humpback or Panther Grouper) </li></ul>
Sweetlips Haemulidae Photograph by Jos Hill <ul><li>ID TIPS </li></ul><ul><li>40-80cm in length </li></ul><ul><li>Low set mouths with thick lips, especially the upper lip, which protrudes over the bottom (the opposite to the grouper) </li></ul><ul><li>Foreheads slope more steeply and appear as a quarter of a circle </li></ul>Photograph by Jos Hill
Sweetlips Haemulidae Photograph by Cori Kane Photograph by Jos Hill Photograph by Jos Hill Photograph by Dean Miller <ul><li>ID TIPS </li></ul><ul><li>Thicker body (top to bottom) than a grouper </li></ul><ul><li>Top lip over bottom (opposite from grouper) </li></ul>
<ul><li>ID TIPS </li></ul><ul><li>Often found in large schools </li></ul><ul><li>Many species range between 20-50cm in length </li></ul><ul><li>Shallow sloping forehead </li></ul><ul><li>Thin lips </li></ul><ul><li>Angular shape of head </li></ul>Snapper Lutjanidae Photograph Dean Miller Photograph by Cori Kane Photograph by Jos Hill Photographs by Dean Miller Photographs by Dean Miller
Photograph by Dean Miller Photograph by Dean Miller Snapper Lutjanidae Emperors have a more sloping head and tend to be alone Photograph by Steve Cutler Photograph by Dean Miller
Humphead Wrasse Labridae Cheilinus undulatus Photograph by Dean Miller Photograph by Dean Miller <ul><li>ID TIPS </li></ul><ul><li>Huge fish - up to 2m long </li></ul><ul><li>Hump on their forehead </li></ul><ul><li>Thickened lips </li></ul><ul><li>Eyes can move independently </li></ul>Photograph by Dean Miller Off-transect sightings included ! Photograph by G. Hodgson
Parrotfish Scaridae Photograph by Jos Hill Photographs by Jos Hill Photograph by Georg Heiss <ul><li>ID TIPS </li></ul><ul><li>Large scales </li></ul><ul><li>Swim with pectoral fins </li></ul><ul><li>Fused teeth form a beak </li></ul><ul><li>Often green with blue and pink marks </li></ul>Photograph by Jos Hill
Parrotfish Scaridae Photographs by Jos Hill Photographs by Jos Hill Photographs by Jos Hill Count parrotfish over 20 cm Photographs by Jos Hill Photographs by Jos Hill
Bumphead Parrotfish Scaridae Bolbometopon muricatum Photograph from Undersea Explorer <ul><li>ID TIPS </li></ul><ul><li>Grow up to 130 cm long </li></ul><ul><li>Large bump! </li></ul><ul><li>Typically feed in schools </li></ul>Photograph by Undersea Explorer Photograph from Undersea Explorer
Bumphead Parrotfish Scaridae Bolbometopon muricatum Photographs from Undersea Explorer Off-transect sightings are included!
Photograph by Jos Hill Butterflyfish Chaetodontidae Photograph by Jos Hill <ul><li>ID TIPS </li></ul><ul><li>Small, disc-shaped, laterally compressed </li></ul><ul><li>Small protruding mouths - pick at the reef </li></ul><ul><li>Bright yellow, black, white colours </li></ul>Photograph by Undersea Explorer Photograph by Jos Hill Photograph by Jos Hill Photograph by Steve Cutler
Butterflyfish Chaetodontidae Photographs by Jos Hill Do not confuse with angelfish, which are more colorful, solitary and larger
DO NOT CONFUSE Moorish Idols ( Zanclus cornutus ) with butterflyfish. THESE SHOULD NOT BE INCLUDED IN THE SURVEY. Photograph by Undersea Explorer Photograph by Gerick Bergsma Butterflyfish Chaetodontidae
Butterflyfish Chaetodontidae Butterflyfish Butterflyfish Moorish Idol <ul><li>ID Tips for distinguishing bannerfish (butterflyfish) from Moorish Idol: </li></ul><ul><li>Moorish Idols have elongated, snooty noses with a yellow bridge </li></ul><ul><li>Bannerfish have no yellow on body, only fins </li></ul><ul><li>Moorish Idols have spine-like projections above their eyes and mostly black fins </li></ul><ul><li>Scales on Moorish Idols are not apparent, whereas opposite is true of bannerfish </li></ul>
Moray Eel Muraenidae Photograph by Dean Miller Photograph by Dean Miller Photograph by Undersea Explorer <ul><li>ID TIPS </li></ul><ul><li>Hide in holes </li></ul><ul><li>Often still with their mouths open </li></ul>