Recovery Potential Assessment for Fraser River을 추천으로 읽었다. CSAS 2023/003으로 프레이저강의 홍연어 복구평가에 대한 연구다. 1 지정단위별로 4평방키로미터(2키로*2키로)단위의 격자로 산란지를 구분하여 2만평방키로를 조사했고 정확도는 가장 낮은 1부터 거의 완벽한 5까지 구분했다. 22 1984년부터 2016년까지의 관측으로 2032년까지를 예측했으며 25%에서 75%가능성구간도 추가했다. 25 전체적으로 연어의 크기와 성숙연령이 감소하고 있으며 홀수해에는 더 적은 물고기가 산란여행으로 돌아오고 새끼도 더 늦게 성숙하고 있다. 33
성공적인 부화는 수온, 용존산소, 그리고 침전물에 좌우된다. 4-13도의 수온에서 부화하며 최적은 11도전후다. 최소 리터당 5미리그램의 용존산소가 필요하고 과도한 모래는 치어에게 방해된다. 유속과 결빙온도는 알의 생존에 영향을 끼친다. 부화된 치어는 노른자를 모두 소모하면 자갈에서 나와 먹이사냥에 나선다. 35 부화된 치어는 바다로 내려가 근해에서 겨울을 보내고 여름에는 원양으로 먹이를 찾아 이동하고 산란을 위해 다시 강으로 돌아오는 이주패턴을 보이고 있다. 47
외래종인 농어는 먹이경쟁을 통해 연어생존에 심각한 영향을 미칠 수있다. 또한 알이나 연어치어를 먹기도 한다. 이를 억제하기위해 하루 최대 400마리의 농어를 어획하기도 했다. 92/263
https://www.isdm-gdsi.gc.ca/csas-sccs/applications/Publications/index-eng.asp
ABSTRACT ................................................................................................................................. xiii
INTRODUCTION ...................................................................................................................... 1
SPECIES INFORMATION .................................................................................................. 1
LISTING AND RECOVERY BACKGROUND ..................................................................... 4
BIOLOGY, ABUNDANCE, DISTRIBUTION, AND LIFE HISTORY PARAMETERS ................. 5
ELEMENT 1: SUMMARY OF SOCKEYE SALMON BIOLOGY ......................................... 5
ELEMENT 2: EVALUATION OF RECENT SOCKEYE SALMON ABUNDANCE TRAJECTORY, DISTRIBUTION, AND NUMBER OF POPULATIONS .................................... 9
ELEMENT 3: RECENT LIFE HISTORY PARAMETERS ................................................. 20
HABITAT AND RESIDENCE REQUIREMENTS .................................................................... 22
ELEMENT 4: HABITAT PROPERTIES THAT SOCKEYE SALMON NEED FOR SUCCESSFUL COMPLETION OF ALL LIFE-HISTORY STAGES ......................................... 22
ELEMENT 5: INFORMATION ON THE SPATIAL EXTENT OF THE AREAS IN SOCKEYE SALMON DISTRIBUTION THAT ARE LIKELY TO HAVE THESE HABITAT PROPERTIES ............................................................... 24
ELEMENT 6: PRESENCE AND EXTENT OF SPATIAL CONFIGURATION CONSTRAINTS ....................................................................................................................... 34
ELEMENT 7: EVALUATION OF THE CONCEPT OF RESIDENCE AND DESCRIPTION FOR SOCKEYE SALMON ...................................................................................................... 35
THREATS AND LIMITING FACTORS TO THE SURVIVAL AND RECOVERY OF FRS ....... 36
ELEMENT 8: THREATS TO SURVIVAL AND RECOVERY ............................................ 36
ELEMENT 9: ACTIVITIES MOST LIKELY TO THREATEN THE HABITAT PROPERTIES IDENTIFIED IN ELEMENTS 4-5 ........................................................................................... 118
ELEMENT 10: NATURAL FACTORS THAT WILL LIMIT SURVIVAL AND RECOVERY .............................................................................................................................................. 118
ELEMENT 11: DISCUSSION OF THE POTENTIAL ECOLOGICAL IMPACTS OF THREATS FROM ELEMENT 8 TO THE TARGET SPECIES AND OTHER CO-OCCURRING SPECIES, CURRENT MONITORING EFFORTS, AND KNOWLEDGE GAPS .................... 122
ELEMENT 14: PROVIDE ADVICE ON THE DEGREE TO WHICH SUPPLY OF SUITABLE HABITAT MEETS THE DEMANDS OF THE SPECIES BOTH AT PRESENT AND WHEN THE SPECIES REACHES THE POTENTIAL RECOVERY TARGET(S) IDENTIFIED IN ELEMENT 12. ............................................................................................................................................. 123
SCENARIOS FOR MITIGATION OF THREATS AND ALTERNATIVES TO ACTIVITIES ... 125
ELEMENT 16: INVENTORY OF FEASIBLE MITIGATION MEASURES AND REASONABLE ALTERNATIVES TO THE ACTIVITIES THAT ARE THREATS TO THE SPECIES AND ITS HABITAT ............................................................................ 125
ELEMENT 17: INVENTORY OF ACTIVITIES THAT COULD INCREASE THE PRODUCTIVITY OR SURVIVAL PARAMETERS ................................................................. 147
ELEMENT 18: IF CURRENT HABITAT SUPPLY WAS INSUFFICIENT TO ACHIEVE RECOVERY TARGETS (SEE ELEMENT 14), ADVICE ON THE FEASIBILITY OF RESTORING THE HABITAT TO HIGHER VALUES................... 147
ELEMENT 22: ALLOWABLE HARM ASSESSMENT ........................................................... 147
DU2 BOWRON-ES ......................................................................................................... 149
DU10 HARRISON (U/S)-L .............................................................................................. 149
DU14 NORTH BARRIERE-ES ....................................................................................... 150
DU16 QUESNEL-S ........................................................................................................ 151
DU17 SETON-L .............................................................................................................. 152
DU20 TAKLA-TREMBLEUR-ESTU ................................................................................ 153
DU21 TAKLA-TREMBLEUR-S ....................................................................................... 154
DU22 TASEKO-ES ......................................................................................................... 155
DU24 WIDGEON-RT ...................................................................................................... 156
CONCLUSIONS ........................................................................................................... 157
REFERENCES CITED .......................................................................................................... 157
APPENDIX A. LIST OF WATERBODIES WITHIN FRS DUS (COSEWIC 2017) ..................... 189
APPENDIX B. COSEWIC THREATS TABLES ......................................................................... 194
APPENDIX C. SOURCES OF UNCERTAINTY AND RESEARCH NEEDS ............................. 248