-

1.2.3.4.5.6.7.

1.

Important Resource Species - Fishes 42% 58%

(1) Marine fishes a. Pelagic Coastal mackerel (Scombridae) sardine, herring (Clupeidae) Oceanic tuna (Scombridae) b. Bottom cod and hake (Gadidae) croaker (Scianeidae)

(3) Diadromous fishes a. Anadromous fishes salmon (Salmoniformes) b. Catadromous fishes eel (Anguilliformes) c. Amphidromous fishes goby (Gobiidae) (2) Freshwater fishes carps and minnows (Cyprinidae)carpeelsalmongoby

Northern (California) anchovyEngraulis mordax

Southern (Peruvian) anchovyEngraulis ringens (Anchovy) v.s. (Upwelling)

2.

(1) 200 8865

(2) 12200 15-25

(3) (12) 4

(4) () () () () ()625

3.

(1) Stock identification () a.

b. Allozyme Nuclear DNA Cytoplasmic DNA

(2) Migration ()A generalized life history triangle for marine species; not all species have geographically separate spawning and nursery areas

a. ()

1.

2.

b. Skipjack tuna ()

c. Atlantic salmon ()

Life cycle of the eelGlass eel Yellow eel LeptocephalusSpawningSilver eel OceanContinentEggd. Japanese eels ()

160

e. Goby ()AdultEggLarvaPostlarvaJuvenileRIVERNEARSHORE OCEAN

Diadromy () B: birth, G: growth, R: reproduction

Why migrate?

a. To increase the evolutionary fitness (W)

Wlx bx lx: survival rate at age x bx: fecundity and breeding success at age x

W (D)W (ND)

D: diadromous population ND: non-diadromous population

b. Selection gradient (food or temperature) Northern fishes: sea direction Southern fishes: freshwater direction

(3) Reproduction and Recruitment a. Age at first maturity (biological minimal size) () (salmon, eel) 1/4 1/3

b. Gonadosomatic index (GSI,) Gonad weight / body weight 100 %SETSSETSSE: southern area of East China SeaTS: Taiwan strait

c. Fecundity () Number of eggs being readied for the next spawning by a female

Larger cod or flounders produce more than 1,000,000 eggs at one spawning. Oysters: tens of millions of eggs at one spawningDominant year class () more fecund species fluctuate more in abundance than the less fecund species.Fluctuation of population () natural causes or the effects of fishing

(4) Age and Growtha. Mark and recapture

b. Length frequency analysisTotal length (cm)Frequency (%)Frequency (%)Carapace length (mm) Mackerel Scomber sp. Banana prawns Penaeus merguiensis

c. Age marks in hard tissuesc-1. Scale ()

c-2. Otoliths () - Sagitta, Lapillus, and Asteriscus (1) Translucent and Opaque zones (2) Daily growth increments (rings)(1)(2)

c-3. Vertebrate ()

a. Maximum age and size b. Growth rate c. Factors affecting growth rate 1. Inheritance (endogenous factors) - Growth hormone - Sexual differences in growth rate - Larval period rapid rates of growth and sudden changes in food and body shape 2. Environmental factor (exogenous factors) - Difference stocks grow at different rates - Quantity and quality of food - Temperature - Migration - Living space(4) Growth

a. Length Weight relationship W a Lb log W log a b log L

b. Condition factor () W k L3 k W / L3

c. Allometric growth vs isometric growthLoge lengthLoge weightLength (mm)Weight (g)(5)

d. Growth equation Lt = L [1 - e -k (t - to) ]

4.

teleost fish (fecundity) (103~106 eggs per year) (mortality) (99.90~99.95 %) survival recruitment adult stock Regulation of recruitment ()

a. Starvation hypothesis Critical phase () recruitment

b. Predation hypothesis

c. Bigger-is-better hypothesis

d. Advection hypothesis

5.

Population dynamics

(1) (Surplus yield models)(MSY, maximum sustainable yield)

(2) (Yield per recruit model)

(3) (Stock-recruitment relationship)

6.

(Minamata desease)()()19531960100 Minamata ()HgCl2197724,200

Conservation method By catchTED (Trawl efficient devices)A bird scaring deviceFrom Jennings S, Kaiser MJ, Reynolds JD (2001) Marine Fisheries Biology, Fig. 4.5, p76

1.

2.

3.

4.

5. 7.