1、第一章 漁業(yè)資源數(shù)量變動的一般規(guī)律第一節(jié) 研究資源數(shù)量變動的基本單位第二節(jié) 資源數(shù)量變動的基本原因及其一般規(guī)律第三節(jié) 捕撈對魚類資源數(shù)量變動和漁獲數(shù)量與質(zhì)量所產(chǎn)生的影響第一節(jié) 研究資源數(shù)量變動的基本單位1、漁業(yè)資源總量：海洋和內(nèi)陸水域中魚類資源蘊藏量，還包括非魚類的海洋經(jīng)濟動植物2. 經(jīng)濟漁業(yè)資源：海洋與淡水中達到捕撈規(guī)格的經(jīng)濟水生動物的總量。3. 預備資源：未達到可捕規(guī)格的補充群體總量。Types of fisheries resourcesFish species: pelagic fishdemersal fish(King 2007)Types of fisheries resourc

2、esShellfish species CrustaceansMolluscs(King 2007)Types of fisheries resourcesMajor group of commercially important species漁業(yè)統(tǒng)計年鑒 2015年全國海洋捕撈產(chǎn)量 （噸）Types of fisheries resourcesMajor group of commercially important species漁業(yè)統(tǒng)計年鑒 2015年全國部分海洋魚類捕撈產(chǎn)量 （噸）漁業(yè)資源分類與管理Short-lived species with high fecundityLarg

3、e fluctuations in recruits and stock sizesDensity-independent factors more importantLarge variations in catchLong-lived species with low fecundityStrong stock-recruits relationshipDensity-dependent factors more importantMore constant yieldLife history types: r selection and K selection (Pinaka, 1970

4、)(King, 2007)Life History Types: (Winemiller 2005)Types of fisheries resourcesProtected: Marine mammals, Seabird Sea turtlesEndangered: Other long-lived speciesInvasive species 漁業(yè)資源的分布Distribution pattern:Sunlight and nutrientsPhytoplankton Primary productivityFisheriesMechanisms for high nutrients

5、in photic zonesTerrestrial sources for inshore areaConvection currentUpwelling漁業(yè)資源的分布Latitude: high species diversity but low population sizes in tropical area low species diversity but high abundance in temperate watersTemperate waters: worlds large fisheries based on relatively few cool-water spec

6、iesCoastal and tropical waters: small catches from a much greater variety of species種群（Population)種以下的分類單位，見“漁業(yè)資源生物學”定義及鑒定方 法。指在特定時間內(nèi),占據(jù)特定空間的同種有機體的集合群，是僅次于種的一個分類單位，也是漁業(yè)資源評估的單元。密度、出生率、死亡率、年齡分布、生物潛能、分散和增長型Stock亞種群或種下群（Subpopulation): 比種群范圍更小，作為數(shù)量變動的基本單位更合適。單位資源群體（Unit Stock):相同品種的一群個體，它基本是一個具有自身 產(chǎn)卵場而且

7、不會因洄游遷入遷出而變化的獨立的群體，有時多品種魚群也可作為單位資源群體。費鴻年（1990）種族、種群、群體、亞種群是物種存在的具體形式魚類群體是由可充分隨機交配的個體群所組成，具有時間或空間的生殖隔離以及獨立的洄游系統(tǒng)，在遺傳離散性上保持著個體群的生態(tài)、形態(tài)、生理性狀的相對穩(wěn)定，是水產(chǎn)資源研究和管理的基本單位。第二節(jié) 資源數(shù)量變動的基本原因及其一般規(guī)律一、資源數(shù)量變動的基本原因 內(nèi)因：生物因素 外因：環(huán)境因素（自然環(huán)境、人為環(huán)境）1. 生物因素繁殖：親體數(shù)量，成活率生長：餌料和水文條件，密度、水溫死亡：自然死亡（餌料、疾病、外界環(huán)境劇變） 卵-受精卵-仔稚魚-成魚補充死亡率達99.9% 2、

8、環(huán)境因素：水溫、鹽度、海流種間關(guān)系、敵害生物捕撈因素二、資源數(shù)量變動的基本模型1、Russell(英國，1931) 影響資源數(shù)量變動的四個因素 B2= B1 + (R+G) - (M+Y)B2= B1 + (R+G) - (M+Y)B2、B1: 時間2、1時的種群數(shù)量； R：補充量； G：生長； M：自然死亡； Y：捕撈死亡 當B2 B1，則資源處于增加狀態(tài)；當B2 = B1，則資源處于平衡狀態(tài)；當B2 B1，則資源處于減少狀態(tài)。Schaefer & Beverton(1963) dB/dt=0, 資源處于平衡狀態(tài) F(f) = r(B) + g(B) - M(B) 平衡漁獲量: Y = F(

9、f) B = r(B) + g(B) - M(B) B 把R、G、M綜合考慮：Schaefer剩余產(chǎn)量模型 把R、G、M分別考慮：Beverton-Holt動態(tài)綜合模型 漁業(yè)資源群體可分為兩部分，即補充群體（recruitment）和 剩余群體(surplus)。（1）生物學含義 （2）漁業(yè)上的含義三、補充群體和剩余群體的數(shù)量變動1. 生物學的觀點補充群體：魚類經(jīng)卵、仔魚生長為幼魚，再進入產(chǎn)卵場的群體。亦即第一次性成熟個體。（客觀的）。剩余群體： 重復產(chǎn)卵群體為剩余群體。2. 漁業(yè)的觀點補充群體：凡幼魚長大到一定規(guī)格，進入漁場與漁具相遇，并被大量捕撈的群體。（主觀的，人為的）。剩余群體：首次捕

10、撈后剩余的群體。定義的外延如果漁場只限于產(chǎn)卵場，如果漁業(yè)還利用索餌場、越冬場例如黃海鯡和藍點馬鮫：性成熟年齡為齡，大量捕撈年齡為齡和當年生魚。補充過程：補充量補充年齡補充方式： （1）一次性補充（刀刃型）。 （2）分批補充：同一世代隨生長速率不同而分 批。 （3）連續(xù)補充：隨時生長，隨時補充到成體中，主要是熱帶魚種。影響因素補充群體數(shù)量變動的原因復雜：親體數(shù)量、水文環(huán)境（溫、鹽、流）、敵害、餌料。剩余群體數(shù)量變動的原因：捕撈為主要因素，世代數(shù)量。一般補充量較產(chǎn)卵量少很多：餌料和死亡除一些中上層魚類的補充年間波動很大，一般魚類的補充量都比較穩(wěn)定，特別是壽命較長的底層魚類。第三節(jié) 捕撈對魚類資源數(shù)

11、量變動和漁獲數(shù)量與質(zhì)量所產(chǎn)生的影響表1-1，長命魚類和短命魚類年存活的比較年死亡率%年齡0123456782010008006405124103282622101687010003009027821表1-2，世代強度相同的各齡存活數(shù)（年死亡率20%） 在一年中出現(xiàn)的每一年齡的魚類數(shù)字（行，橫向）和在其生命期間連續(xù)年齡中一個世代的魚類數(shù)目（斜向）相同。在某一年中各年齡的資源數(shù)量的下降反映出魚類的死亡率。年份年齡0123419891000800640512410199010008006405124101991100080064051241019921000800640512410199310008

12、00640512410通常世代強度逐年變化不定：表1-3，每一年齡的魚類存活數(shù)及變化的世代強度（年死亡率20%）任何一年資源的年齡組成還取決于世代的波動率。若波動不大，年齡組成仍反映死亡率的平均衰減情況。年份年齡01234198910008809603074101990900800704768246199113007206405636141992600104057651245119931000480832461410自然死亡捕撈死亡Z= M+F第四節(jié) 漁業(yè)數(shù)據(jù) Catch data: commercial & recreational Age/size composition data Cat

13、ch-at-age data Fishing effort data Abundance index data Weight-length, age-length data Fecundity data Maturation data Gear selectivity data Tagging dataSome typical fisheries dataFisheries-dependent monitoring programLogbook, port sampling, sea sampling (observer program)Fisheries-independent progra

14、m (scientific survey)stratified random survey, systematic survey Surveying fishermendeveloping questionnaires to understand social problems fishing industries face.Programs to collect data for stock assessment and managementMonitoring ProgramsFisheries independent program has good representative of

15、fish stocks, but expensiveFisheries dependent program provide greater quantities of data at lower costs than fisheries independent programsExample: size measurementFisheries-dependent Monitoring ProgramTarget: fishermen, dealers, processors, buyers,Logbook: voluntary and mandatorySea and dock sampli

16、ng:Design: When, where, from whom, and how to sampleImportant considerations: randomness, efficiency, practical, cost-effective, achievable, back-up plan. To measure: biological, fisheries, and social variables A typical form for fishermen Fisheries Dependent MonitoringMultiple fisheries dependent m

17、onitoring programs are commonMultiple programs Allow several unique sampling designsHelp address problems with data qualitySpatial and temporal coverageAddress concerns of different groupsQuality of fisheries data Accuracy Precision Sampling representative Temporal and spatial coverageThe quality of

18、 information depends onCoverage of vessels with onboard observersFishing behavior of vessels(1) Type of data(2) Design of survey programs(3) Experience of technicians(4) Nature of fisheries(5) Management strategy/plan(6) Interactions of fishermen and managers(7) Environmental factors(8) Economic, so

19、cial, and/or ecological valuesFactors influencing data qualityData diversity: sources of dataLength of time seriesNumber of variablesSample sizes: effective sample sizes (lots of data from one sampling site versus a few samples per site from many sites), e.g., size composition data estimatesSample r

20、angesQuantity of the dataFactors Influencing Data Quantity(1) Economic and/or social values of fisheries(2) Stage of fisheries development(3) Ecological importance of fisheries(4) Spatial and temporal distributionsSource of Error Measurement error Model error Process error Operating errorNature of t

21、he errorsMagnitude of the errorsMethod to collect the informationon-board observer programlog-book The quality of information depends onCoverage of vessels with on-board observersFishing behavior of vesselsExample: Biased Errors in Catch dataDiscardingAt-sea discarding: discard part of the catch bac

22、k into the sea before landing10% of the total world catch discarded(e.g. 80 million cod discarded in the cod fishery off the northern coast of Norway in the 1986-87 fishing season)Factors influencing discarding:MarketHolding capacityRegulationsNature of fisheriesBiased estimates of the total catchBi

23、ased estimates of age compositionBiased estimates of stock size?Biased estimates of exploitation rate?Direction of the biases?Consequences to fisheries population dynamics study if we dont include discarded catch Sample Survey DesignsBased on statistical principle Why?Where?When?How?Types of Samplin

24、gNonprobability SamplesJudgmentUse experience to select sampleExample: sentinel fixed stationsQuotaSimilar to stratified sampling except no random samplingChunk (convenience)Use elements most availableSimple Random SampleEach population element has an equal chance of being selectedSelecting 1 subject does not affect selecting othersMay use random number table, computerSimple Ra