Zoogeography and Habitat Adaptations

58%

fish species are found in marine environments.

41%

fish species are found in freshwater environments.

Epipelagic Zone

Surface to 200m depth, contains 1.3% of total fish species.

Deep Pelagic Fishes

Over 1400 species inhabit depths greater than 200m.

Mesopelagic Zone

Located between 200-1000m depth.

Bathypelagic Zone

Deeper than 1000m in the ocean.

Deep Benthic Zone

Contains 6.4% of marine fish species.

Littoral Zone

Includes continental shelf fishes that inhabit shore and shelf above 200m.

Freshwater Species Distribution

Higher diversity due to genetic isolation and energy availability.

Primary Freshwater Species

Strictly confined to freshwater environments.

Secondary Freshwater Species

Species that may occasionally enter saltwater.

Peripheral Freshwater Species

Spend part of their life cycle in both fresh and saltwater.

Indo-West Pacific Region

Most diverse marine zoogeographic region.

Western Atlantic Region

One of the key marine zoogeographic regions.

Eastern Pacific Region

Another important marine zoogeographic region.

Species Richness

Higher concentration of species found in tropical areas.

Dispersal Patterns

Typical travel and speciation of fish across barriers.

Sheepshead Minnow

Example of a species with a wide salinity tolerance.

Neartic Region

One of the freshwater zoogeographic regions.

Neotropical Region

Another key freshwater zoogeographic region.

Afrotropical Region

A significant region for freshwater fish distribution.

Indo-Malay Region

A freshwater zoogeographic region with unique species.

Australian Region

Region known for its distinct freshwater fish species.

Paleartic Region

Known for freshwater species distributions in the northern hemisphere.

Vicariant Events

Events that isolate previously connected populations of fish.

Continental Drift

Movement of continents that influences fish distribution.

Scomberomorus maculatus

North Atlantic mackerel species.

Ecological Pressures

Factors like temperature and pressure affecting fish survival.

Photophores

Light-emitting organs found in some deep-sea fishes.

Bioluminescence

Light production in organisms, evolved independently in five superorders.

Deep Sea Food Chains

Originates in the euphotic zone where light penetrates.

Antarctic Water Temperatures

Range from -2 to 2 degrees Celsius.

Antifreeze Compounds

Found in Antarctic fishes to prevent freezing.

Arctic Fishes

Most are cold-tolerant species from Atlantic or Pacific waters.

Extreme Adaptations

Desert fishes tolerate extreme salinity and temperature variations.

Diapause

Life history stage allowing survival during dry periods.

Estivation

Dormancy period for adults during dry seasons.

Waterfall Climbing Fish

Example includes Sirajo goby with adaptations for high-energy environments.

Cave Fish Adaptations

Includes lack of pigmentation and blind features.

Cryptoria thamicola

Species adapted to cave environments and high-energy habitats.

Horizontal Orientation

Adaptation in pectoral fins for species in turbulent waters.

Large Mouths in Deep Sea Fishes

Adaptation to maximize feeding opportunities in a scarce environment.

Deep Sea Carnivores

Fishes that utilize lures to attract prey.

Mesopelagic Fish Behavior

Tend to migrate vertically to feed during the night.

Cold-Tolerant Species in Arctic

Fewer endemic species compared to Antarctic.

Accessing Oxygen in Arid Regions

Fishes develop accessory respiratory structures.

Reduced Squamation

Adaptation in cave fishes for a constant environment.

Expanded Lateral Line

Enhancement in cave fishes for better sensory detection.

Long Parental Care in Cave Species

Adaptation for lower reproductive rates.

Dorsal Fin Modifications

Can serve as lures in deep-sea fish.

Compensatory adaptations

Mechanisms fish develop in difficult environments.