Life in Lake Atitlan (Ati Divers, La Iguana Perdida, Guatemala)

8/14/2019 Life in Lake Atitlan (Ati Divers, La Iguana Perdida, Guatemala)

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Black Crappie, Calico Bass (Pomoxis Nigromaculatus)

DescriptionCrappie is a member of the sunsh family

Centrarchidae, which includes many species

of spiny-nned, freshwater shes with deep,

attened bodies found throughout North

America.

Crappies are the largest of the sunshes,

reaching lengths of up to 30 cm/1 ft or more.

There are two species, the white crappie

(Pomoxis annularis) and the black crappie

(Pomoxis nigromaculatus), though only

black crappie are found in Lago de Atitlàn.

The black crappie has a rounded body with a

greenish back and silvery sides with mottled

black markings. It is this mottled pattern

that gives the black crappie its other com-

mon name: calico bass. Life span for

this species is about seven years.

Habitat and life cycle

Black crappie is a schooling shand lives in temperate ponds, lakes,

streams, and resevoirs.

Black crappie prefer

fertile lakes with rm

bottoms and lots of

plants and underwa-

ter structures like

logs, stumps

and rocks.

Life in the LakeBy day, crappie tend to be less active and to

concentrate around weed beds or submerged

objects. They feed especially at dawn and

dusk, moving into open water or approaching

the shore. Adults feed mainly on smaller sh

(including the young of their own predators),

insects, craysh and tadpoles. Young sh eat

zooplankton (microscopic animals and other

organisms including water eas, mosquito

larvae, paramecia, amoebas, etc.) and grow

5–7 cm/2–3 in. their rst year. Black crappie

are preyed on by any larger shes, as well as

by herons and turtles.

Due to the species’ great range, breeding

season varies by location, but breeding

temperature is from 14–20 °C (58–68 °F).Crappie are sexually mature after 2–3 years.

Black crappie spawn in the same way as blue-

gill and other members of the sunsh family:

males rst sweep out a nest in sand or gravel

in water 1–2 m/3–8 ft deep. Females then lay

up to 60 000 eggs in the nests before leav-

ing the males to guard the eggs, which hatch

after about a week. The newly hatched sh

stay in the nest a few days while they develop

a functional mouth, then move into the watercolumn. Males stay with the young until they

are able to start feeding.

The crappie’s common name (also

spelled croppie or crappé), derives

from the Canadian French “crapet.”



Bluegill sunfish, Bream

(Lepomis macrochirus)

Description

Bluegill, also commonly referred to as bream,

is a member of the sunsh family (family

Centrarchidae). It is a deep, at-sided sh

with a small mouth and long pectoral ns.

Colouration varies, but the opercular ap

(ear ap), an extension of the gill cover, is

always blue-black and bluegills have a black

spot near the back of the dorsal n. Bluegill

also have darker vertical bars along the sides

of the body, though these are not always

pronounced. The name comes from the bright

blue edging on the gill rakers.

Bluegill grow to a maximum length of

approximately 40 cm/16 in. Specimens in the

lake frequently reach 15–20 cm/7–10 in.


Bluegill’s preferred habitat is clear,

temperate lakes with some rooted vegetation.

This sh is native to a wide area of North

America, from Quebec to northern Mexico,

and has been widely introduced to stock

game sh for anglers. Bluegill was introduced

to Lago de Atitlàn along with the black bass

in 1958 as a food source for the bass.

The bluegill’s natural diet consists largely

of small invertebrates and very small sh.

Young bluegill mainly eat zooplankton or

microscopic animals. Adults feed mainly on

aquatic insects.

Life in the Lake

Bluegill is a schooling sh, with schools of

20–30 individuals. They are nest spawnersand typically build nests in large groups.

Males choose an area in shallow water (less

than 1 metre/4 feet deep) and sweep out

a saucer shaped nest with their tails. The

females then lay 10 000–60 000 eggs in

the nests, which are guarded by the males.

The eggs usually hatch in about ve days.

During the nesting period males assume a

very bold colouration. Some males assume

the colouration of the female sh so that the

males guarding the nests won’t be aggressive

towards them, allowing the “sneaker” males

to enter nests and spawn.

The cities of San Francisco, New York

and Washington have used bluegills

for monitoring their water supply

for toxins like pesticides, mercury,

cyanide, heavy metals, fuel spills

and phosphates.

Fish cough by flexing their gills

to expel unwelcome particles, like

grains of sand or chemical residues,

from their breathing surfaces; this

flexing creates tiny vibrations in

the water. Instruments in the water

supply “listen” for these vibrations

and note any unusual amounts of

coughing coming from the fish.



Convict cichlid, Zebra cichlid

(Cryptoheros nigrofasciatus, formerly

Archocentrus nigrofasciatus)

DescriptionThe convict cichlid is one of few native shes

left in Lago de Atitlàn. It is a moderately elon-

gated, laterally compressed sh with an oval

body shape. The body is white to blue grey,

with a grey head and eight or nine dark verti-

cal bars across the body. The belly may have

orange or pink scales.

Males grow to 15 cm/6 in, females to 12 cm/

5 in. Males generally have longer, more ow -

ing dorsal and anal ns, a steeper forehead

and sometimes a head hump. Females have

a rounder belly prole and are usually more

colourful, especially during spawning season,

when they develop a yellow-orange belly to

attract their young.


The convict cichlid is found within

Central America from Lake Atitlàn

and Lake Amatitlan in Guatemala south to lakes in El Salvador, Costa

Rica and Panama.

Central America’s

rocky lake habitat,

formed by volcanic

craters, provides

deep, steep, rocky

sides and hard,

alkaline water.

Life in the LakeThe convict cichlid stays close to cover like

roots, rocks and overhanging banks. Like

most Central American cichlids, it is very

territorial and aggressive. It is omnivorous,

feeding on worms, crustaceans, insects, sh

and plant matter.

Males and females form strong pair bonds,

pairing off after a mating dance. Both

parents dig a pit in the gravel around their

chosen nest site, which is usually a small

cave or grotto. Spawns range from 50–100

eggs for sh less than a year old while older

pairs may lay 300 eggs or more. Once fertil-

ized, eggs are guarded by both parents.

Females fan oxygenated water over them

while males patrol the outskirts of theterritory, chasing away intruders.

The eggs hatch in about 3 days. The wriggling

larvae may be moved by the parents to vari-

ous pits dug in the lake bottom. A week later,

the fry are free-swimming, but parents care

for them for another 3-4 weeks. Convict

cichlids are tireless parents, frequently

exhibiting the following behaviours:

Guarding: Both parents guard the fry, with

the female staying closer to the fry while the

male patrols the perimeter.

Fry retrieval and cleaning: If a fry strays

too far from the group, a parent will swim

to it, take the fry in its mouth and return it

to the school. Parents also clean fry by tak-

ing them in their mouths and “chewing” a bit

before spitting them back out.

Fin-digging and leaf-turning: Parents stir

up food for the fry by wriggling in the gravel.

They also turn over leaf litter on the bottomto expose invertebrate food items living on

the undersides.

Because the convict cichlid is very

hardy, thrives in almost any water

conditions, is easy to breed in

captivity and exhibits remarkable

parental behaviour, it is one of the

most popular cichlids for aquarium

hobbyists.



Black bass, Largemouth bass

(Micropterus salmoides)

Description

The name “black bass” is collectively used for

three species of bass: the largemouth, small-mouth and spotted bass. Lago de Atitlàn’s

black bass is the largemouth bass, Microp-

terus salmoides. The largest member of the

sunsh family Centrarchidae, it is bronze to

green with dark blotches forming a stripe

along the sides of the body. Because the

upper jaw extends behind the eye, its mouth

is relatively large, as the name suggests.

Black bass typically reach sexual maturity

at about 25 cm/10 in length, which can be assoon as one year. In two years, the bass have

attained record size, with an average weight

of 4kg/9lbs.


Black bass survives well in almost any clear-

water environment. Its original distribution

covered most of the U.S and Canada east of

the Rocky Mountains, but the species has

been introduced into most of Mexico and

Central and South America, as well as a wide

area of Europe.

The black bass spends most of its time in its

home range, a small, concealed area of deep

cover near logs, docks, underwater ridges,

submerged brush and rocks, quietly waiting

for food to come its way.

Life in the Lake

Black bass has a voracious appetite and will

feed on anything that moves, swallowing its

prey whole. In its native range, it is such a

erce predator that it has caught and killed birds such as swallows, warblers and red-

winged blackbirds as they y near the

surface of the water. Starting at about 5 cm/

2 in. length, they begin to prey on smaller

sh, frogs, snails, worms, insects, craysh,

crabs, lizards and young birds. In their na-

tive range, they contribute to the overall

health of the ecosystem by keeping bluegill

and other sh populations under control.

Introduced to Lago de Atitlàn in 1958, the

bass have eliminated many other species of

sh from the lake, and have almost certainly

played a role in the disappearance of the

giant grebe, an endemic species now extinct.

During spawning season, the male selects a

sunny spot in quiet shallows up to 2 m/8 ft

deep, courts a female, and persuades her to

deposit eggs in his nest. Each female lays up

to 40 000 eggs; once the male has fertilized

the eggs, he guards them until they hatch5–10 days later. Once hatched, the young

begin feeding on plankton and insect larvae.

In many parts of the United States,

black bass is the most popular game

fish; an estimated 26 million Ameri-

cans fish for this species. The meat

is light, flaky and tasty, with low

oil content.

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Life in Lake Atitlan (Ati Divers, La Iguana Perdida, Guatemala)