Biology of Aquaculture Species

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Biology of Aquaculture Species Study of aquatic organisms (fish, crustaceans, mollusks, echinoderms) reared in controlled or semi-controlled environments. Focuses on their biology, habitat preferences, morphology, and reproduction methods. Food Fish Classification Fish Fin Fish Freshwater Fish Brackish water Fish Marine water Fish Invertebrates Shell Fish Crustacean Mollusk Univalve Bivalve Cephalopod Echinoderms Habitat Types Saltwater Fish Habitats Coastal fish Deep sea fish Pelagic fish Demersal fish Coral reef fish Freshwater Habitats LENTIC Ecosystems: Standing water bodies (Lakes, ponds, swamps) LOTIC Ecosystems: Flowing water bodies (rivers, canals, streams) Brackish Water Fish Species (based on life cycle pattern) Allochthonous from sea Allochthonous from freshwater Major Production Systems in Brackish Water Lagoons: Bodies of water, $\le 5m$ deep, partly separated from the ocean by sand/shingle. Estuaries: Where river meets sea, mixing freshwater and seawater. Mangroves: Coastal ecosystems. Fish Morphology External Anatomy: Nares (Nostrils) Eye Mouth Operculum (Gill Cover) Spiny Dorsal Fin Soft Dorsal Fin Caudal (Tail) Fin Peduncle Lateral Line Vent Anal Fin Pectoral Fins Pelvic Fins Scales Caudal Fin Shapes: Rounded, Truncate, Emarginate, Forked, Lunate Scales Types: Ctenoid (bass), Cycloid (salmon), Ganoid (gar), Placoid (shark) Mouth Types (based on water layer utilization): Final / Terminal Mouth Upper / Superior Mouth Bottom / Inferior Mouth Body Shapes & Locomotion: Fusiform (e.g., Tuna): Fast-swimming in open water. Compressiform (e.g., Tautog): Quick speed for short distances. Depressiform (e.g., Skate): Swims like a flying bird. Filiform (e.g., Pipefish): Slithers through water like a snake. Body Coloration: Counter Shading Cryptic Coloration Disruptive Coloration Reproductive Biology of Aquaculture Species Reproduction: Creation of new individuals from existing ones. Two primary ways in animals: Asexual reproduction Sexual reproduction (fusion of female gamete with male gamete) Common Forms of Asexual Reproduction Budding: (e.g., Hydra) New organism grows out from the body of the parent. Gemmules (Internal Buds): (e.g., Sponges) Parent releases a specialized mass of cells that can develop into a new organism. Fragmentation: (e.g., Planaria) Body breaks into two or more parts, each regenerating the missing pieces. Regeneration: (e.g., Starfish) Ability to regrow lost or damaged body parts, sometimes forming a whole new organism from a fragment. Parthenogenesis: (e.g., Rotifers, Cladocera, Copepoda) Development of an embryo from an unfertilized egg cell. Can involve amictic (asexual) or mictic (sexual) eggs. Sexual Reproduction Fusion (fertilization) of two haploid gametes (sperm and egg) to form a diploid zygote. Basic mechanism is MEIOSIS . Reproduction Modes Oviparity: Lay undeveloped eggs. Broadcast spawning. External fertilization. Release thousands to millions of tiny eggs into water column. Semelparous species: single spawning event (e.g., salmon). Iteroparous species: several breeding events. Annual single-spawners (e.g., catfishes). Annual multiple-spawners (e.g., cichlids, Tilapia). Ovoviviparity: Internal development. No direct nourishment from mother (fertilized eggs carried internally). Larval birth (e.g., guppy, molly, platies, swordtails). Viviparity: Internal development. Direct maternal nourishment (placental). Fully advanced at birth (e.g., advanced sharks, some bony fish, dolphins). Live-bearing. Mating Systems Promiscuous: Both sexes have multiple partners (e.g., mass spawning events, sailfin fish). Polygamous: One sex has multiple partners. Polygyny: Male fish has multiple partners (common). Harem formation: male has breeding rights to a group of females (e.g., wrasses). Polyandry: Female fish has multiple partners (uncommon). Monogamous: One partner (e.g., butterfly fishes, angler fishes, mouth brooders). Genders Gonochoristic: Sex is fixed, one sex (most fishes). Hermaphroditic: Contain both sex organs at some point. Simultaneous: Both sexes at once (e.g., deep water fishes, hamlets). Sequential: Changes sex. Protandrous: Male into female (e.g., moray eels, sea bass). Protogynous: Female into male (e.g., wrasses, parrotfishes). Monomorphic: No visible external differences between sexes (most fishes, e.g., sea cucumber). Sexual Strategies Female investment: "Careful" in mate selection due to Energy investment in eggs. Migration, brooding. Male investment: In reproduction includes Advertisement (colors, tubercles, kypes, secondary sexual characteristics). Mate competition. Nest building, territorial defense, migration. Parental care, brood guarding. Salmon Kype: Hook on lower jaw of mature male salmon to nip and bite other males trying to spawn/fertilize eggs. Tubercles: Small bumps on goldfish, indicator of sexual maturity. Nest Building: Cichlid fish (Lake Malawi): Build bowers to mate. Sergeant Majors: Build nests. Lamprologus callipterus males: Construct shell-nests. Fighter fish/Gourami: Bubble nests (floating masses of bubbles blown with oral secretion). Pufferfish: Male builds elaborate sand circles to attract females and oxygenate eggs. Commercial Aquaculture Species Freshwater Fish Marine Fish Shell Fish Tilapia Salmons Shrimps Carps Sea bass Prawns Trout Sea breams Mussels Eel Clams Catfish Scallops Sturgeon Lobsters Crabs Oysters Life Cycles of Aquaculture Species Fish Life Cycle Broodstock: Mature adults selected for spawning (takes 2-3 years for fry to develop). Fertilized Egg: Develops into larva. Larva: Microalgae fed to rotifers, rotifers fed to fish larvae. Live Feeds: Microalgae, rotifers, artemia. Fry: Fish larvae weaned from live feeds to artificial diets; bigger larvae fed artemia. Fingerling: Fish grow bigger, ready for transfer to farms. Adult: Matures for spawning. Mussel Life Cycle Broadcast Spawning: Adults release sperm and eggs. Fertilization: Forms a fertilized egg. Free-swimming larval stages: Trochophore D-veliger Pediveliger Settlement and Metamorphosis: Larvae settle and transform. Spat: Young mussels. Juvenile Mussels: Further growth. Adult Mussels: Growth and resettlement. Sea Cucumber Life Cycle Spawning: Adults release gametes. Fertilization: Forms a zygote. Larval Stages: 2-cell, 4-cell, 8-cell, Gastrula, Auricularia, Doliolaria, Pentactula. Settlement: Larvae settle. Seeding: Juvenile sea cucumbers. Growth: 1-year old ($\sim 40g$), 2-year old ($\sim 200g$). Eel Life Cycle Eggs Hatch: In Sargasso Sea. Eels Swim to Europe: Larvae drift across Atlantic. Enter Rivers as Glass Eels: Transparent stage. Transform into Elvers (Baby Eels): Pigmented stage. Yellow Eels: Life stage in freshwater, growing to maturity. Fully Grown Silver Eels: Return to seas and migrate to Sargasso Sea. Eels Spawn and Then Die. Brown Trout Life Cycle Spawning (Nov-Feb): Female digs redds, lays eggs, male fertilizes. Eggs covered with gravel. Eggs: 2-5mm, hatch into alevins in a few months. Alevins: Stay in gravel, live off yolk sac, then emerge as fry. Parr: Fry grow into parr; territorial, solitary; need cover and shallow, flowing water. Adults: Develop territory, hide from predators, prefer deeper pools. Migrate to spawn in winter. Live 5-20 years. Green Sturgeon Life History Adults Migrate Upstream (March-April): For spawning. Adults Spawn (April-July): In deep pools, laying thousands of adhesive eggs. Adults Remain (Summer): Leave during first rains in fall. Eggs Hatch: Into larvae, remain upstream. Small Juveniles: Stay upstream or migrate downstream. Large Juveniles: Move between estuary and ocean. Over-winter: North of Vancouver and south of Cape Spencer, Alaska. Adults Migrate Northward (Fall) and Southward (Spring). Salmon Life Cycle Spawning Adults: In river. Eggs: Laid in river. Alevin: Hatched eggs, remain in gravel. Fry: Emerge from gravel, grow in river. Parr: Grow larger in river. Smolt: Transform, migrate to ocean. Adults: Mature in ocean. Return to River: Adults return to spawn.